Methods of Imaging the Urinary Tract PDF

Title: Methods of Imaging the Urinary Tract Name of the instructor: Target population: 40 Scientific Content: 1. Plain radiography 2. Excretion urography (intravenous urogram [IVU]) 3. Ultrasound (US) 4. Computed tomography (CT): (a) CT for urological diagnosis and urological cancer staging (b) CT f...

Title: Methods of Imaging the Urinary Tract Name of the instructor: Target population: 40 Scientific Content: 1. Plain radiography 2. Excretion urography (intravenous urogram [IVU]) 3. Ultrasound (US) 4. Computed tomography (CT): (a) CT for urological diagnosis and urological cancer staging (b) CT for characterization of renal lesion (c) CT adrenals (d) CT KUB (kidneys, ureters, bladder) (e) CT urography (CTU) (f) CT angiography 5. Magnetic resonance imaging (MRI): (a) MR for characterization of renal lesion (b) MR prostate (c) MR bladder (d) MR urography (e) MR adrenals (f) MR angiography 6. Micturating cystography and cystourethrography 7. Ascending urethrography 8. Retrograde pyeloureterography 9. Percutaneous renal procedures: (a) Biopsy (b) Cyst puncture (c) Antegrade pyelography (d) Nephrostomy (e) Percutaneous nephrolithotomy 41 10. Arteriography 11. Venography 12. Conduitogram 13. Radionuclide imaging: (a) Static renography (b) Dynamic renography (c) Radionuclide cystography direct and indirect. PLAIN FILM RADIOGRAPHY Indications Predominantly to evaluate renal tract calcifications recognizing that CT is significantly more sensitive (>98% compared with 60% for plain films). Technique As for preliminary films for excretion urography (discussed later). INTRAVENOUS EXCRETION UROGRAPHY The technique is less frequently used than in the past and has now been very largely replaced by US, CT or MRI or a combination. Indications 1. Haematuria 2. Renal colic (see the section on variation) 3. Recurrent urinary tract infection 4. Loin pain 5. Suspected urinary tract pathology Contraindications General contraindications to intravenous (i.v.) watersoluble contrast media and ionizing radiation. In patients with contrast medium allergies, alternative modalities such as ultrasound or MR can be considered. Patients with impaired 42 renal function, particularly those with diabetes, should be prepared with oral or i.v. hydration, or an alternative imaging modality should be considered. Contrast Medium Low osmolar contrast material (LOCM) 300 Adult dose 50 100 mL Paediatric dose 1 mL Patient Preparation 1. No food for 5 h prior to the examination. Dehydration is not necessary and does not improve image quality. 2. The routine administration of bowel preparation has been shown not to improve the diagnostic quality of the examination. Preliminary Images Supine, full-length anterior posterior (AP) of the abdomen, in inspiration. The lower border of the cassette is at the level of the symphysis pubis, and the x-ray beam is centred in the midline at the level of the iliac crests. If necessary, the location of overlying opacities may be further determined by: -ray beam is centred in the midline at the level of the lower costal margin. towards the film) The examination should not proceed further until these images have been reviewed by the radiologist or radiographer and deemed satisfactory. Technique Venous access is established. The gauge of the cannula/needle should allow the injection to be given rapidly as a bolus to maximize the density of the nephrogram. 43 Images 1. Immediate film. AP of the renal areas. This film is exposed 10 14 s after the -tomost dense show the nephrogram at its i.e. the renal parenchyma opacified by contrast medium in the renal tubules. Tomography may assist in evaluation of the renal outline or possible masses (or ultrasound if subsequently available). 2. 5-min film. AP of the renal areas. This film gives an initial assessment of pathology specifically the presence or absence of obstruction before administering compression. A compression band is then applied positioned midway between the anterior superior iliac spines i.e. over the ureters as they cross the pelvic brim. The aim is to produce pelvicalyceal distension. Compression is, however, contraindicated: (a) after recent abdominal surgery (b) after renal trauma (c) if there is a large abdominal mass or aortic aneurysm (d) when the 5-min film shows already distended calyces indicative of obstruction 3. 10-min film. AP of the renal areas. There is usually adequate distension of the pelvicalyceal systems with opaque urine by this time. Compression is released when satisfactory demonstration of the pelvicalyceal system has been achieved. If the compression film is inadequate, the compression should be checked and repositioned if necessary and a further 50 mL of contrast medium administered and a repeat film taken after 5 min. 4. Release film. Supine AP abdomen taken immediately after the release of compression. This film is taken to show the ureters. If this film is satisfactory, the patient is asked to empty the bladder. 5. After micturition film. Full-length supine AP abdomen. The aims of this film are to assess bladder emptying, to demonstrate drainage of the upper tracts, to aid the 44 diagnosis of bladder tumours, to confirm ureterovesical junction calculi, and uncommonly, to demonstrate a urethral diverticulum in females. Additional Images 1. 35° posterior oblique of the kidneys, ureters or bladder for equivocal collecting system lesions or localization of calculi 2. Tomography if renal outlines are not well seen 3. Prone abdomen following the release film may improve visualization of distal ureters 4. Delayed films at increasing (doubling of time intervals) up to 24 h after injection in renal obstruction Variation Renal colic a limited study may be performed: preliminary films; 20-min full length (no compression); postmicturition full length; delayed films up to 24 h as required to show level and cause of obstruction. ULTRASOUND OF THE URINARY TRACT Indications 1. Renal mass lesion 2. Renal parenchymal disease 3. Renal obstruction/loin pain 4. Haematuria 5. Hypertension 6. Renal cystic disease 7. Renal size measurement 8. Bladder outflow obstruction 9. Urinary tract infection 10. Bladder tumour 11. Following renal transplant: 45 (a) Obstruction (b) Patency of vessels (c) Perirenal collections. 12. To guide needle placement in interventional procedures 13. Renal vascular studies. Contraindications None. Patient Preparation Kidneys only none. Kidneys and bladder prehydrate with oral fluids, e.g. 500 1000 mL 1 h before scan; patient attends with a full bladder. This may have the disadvantage of making the collecting systems appear mildly hydronephrotic premicturition. Equipment 3.5 5-MHz transducer. Technique 1. Patient supine, right (RAO) and left anterior oblique (LAO) positions or lateral for kidneys. The kidneys are scanned longitudinally in an oblique coronal plane supplemented by transverse sections perpendicular to the axis. The right kidney may be scanned through the liver and posteriorly in the right loin. The left kidney is harder to visualize anteriorly, but can be visualized from a lateral approach. In difficult cases, the patient should lie on their side with a pillow under the loin to widen the space between the rib cage and pelvis. 2. The length of the kidney measured by US is 1 2 cm smaller than that measured at excretion urography, because there is no geometric magnification. With US measurement, care must be taken to ensure that the true longitudinal length measurement is obtained. The range of lengths of the normal kidneys is 9 12 cm, and the difference between each kidney should be less than 1 2 cm. 46 3. The bladder is scanned suprapubically in transverse and longitudinal planes. Measurements taken of the three orthogonal diameters before and after micturition enable an approximate volume to be calculated by multiplying the three diameters and applying a conversion factor. (A conversion factor [approximately 0.5] is usually preprogrammed into modern ultrasound machines.) 4. Renal transplants are usually located in the right or left iliac fossa. These lie fairly superficially and are easy to evaluate using oblique planes and gentle pressure to displace overlying bowel loops. 5. The native or transplant kidneys can be evaluated for vascular pathology using Doppler techniques. interrogation of the main renal arteries from a transabdominal approach. Elevated peak systolic velocities >200 cm suggestive of a >50% stenosis. Alternatively, as the main renal arteries in the native kidneys are often hard to visualize, the intrarenal arteries can be evaluated from a flank approach for downstream changes in waveform the tardus parvus pattern, a slow rise (tardus) to a reduced peak (parvus), producing a prolonged acceleration time (a value >70 ms is indicative of a severe stenosis). venous flow, direct visualization of thrombus within the distended vein, and a raised resistive index with reversal of arterial diastolic flow within the intrarenal arteries. 47 Title: COMPUTED TOMOGRAPHY URINARY TRACT Name of the instructor: Target population: 48 Scientific Content: Indications 1. Renal colic/renal stone disease 2. Renal tumour 3. Renal/perirenal collection 4. Loin mass 5. Staging and follow-up of renal, collecting system or prostatic cancer (local staging of prostatic cancer is performed using thin-section MRI) 6. Investigation of renal tract obstruction 7. CT angiography may be used to assess renal vessels for suspected renal artery stenosis or arteriovenous fistula or malformation. Techniques Standard diagnostic computed tomography This technique is used to stage and follow-up known renal-tract malignancy or to investigate nonspecific signs attributed to the renal tract. Examination of the thorax in addition to the abdomen and pelvis is usually performed, where pulmonary metastatic disease or mediastinal nodal spread is a possibility: 1. Venous access is obtained. 2. Patient lies supine. 3. Scanogram is taken of chest, abdomen and pelvis as appropriate. 4. 100 mL i.v. LOCM given. 5. Scans obtained approximately 70 s (portal venous phase) after i.v. contrast (arterial phase scans of the liver may be appropriate in those patients with suspected metastatic renal cancer who may have hypervascular liver metastases). Renal lesion characterization computed tomography this is used to assess renal cysts or masses identified on another imaging modality such as ultrasound. Pre- and post-i.v. contrast scans are obtained through the kidneys in order to assess precontrast attenuation and 49 subsequent enhancement patterns. Many practitioners advise the postcontrast scan be performed at 100 s (nephrographic phase) to prevent small intraparenchymal lesions being obscured by corticomedullary differentiation. Adrenal lesion characterization computed tomography Indication: Adrenal mass is suspected or needs characterization. Technique: Unenhanced CT of the abdomen to enable measurement of attenuation (HU) of any adrenal mass. A value less than 10 HU is highly specific for a benign (lipid-rich) adenoma, and is often the only test required. This may, however, be supplemented when necessary by washout CT, remeasurement of the adrenal density in Hounsfield units at 15 min following i.v. contrast. Benign adenomas (whether or not lipid-rich) typically show rapid washout of contrast; an absolute percentage washout (APW) greater than 60% or relative percentage washout (RPW) greater than 40%, on delayed images, is highly specific for a benign lesion. Computed tomography kidneys, ureters, bladder Plain CT (commonly referred to as CT KUB kidneys, ureters, bladder) is useful to assess possible stone disease. It is now used in most centres as the primary investigation of renal colic (replacing plain KUB radiograph): 1. No i.v. or oral contrast is given. 2. Patient supine. (Some authorities advise prone scanning to differentiate if stones are impacted at the vesicoureteric junction or have passed into the bladder.) 3. A low-radiation-dose technique is used to scan from the top of the kidneys to include the bladder base with a slice thickness of 5 mm or less, as determined by CT scanner. (Due to the low-dose nature of the scan and the absence of i.v. and oral contrast, the scan has a very limited role in identifying pathology other than renal tract calculus disease and should not be used indiscriminately for investigation of non-specific abdominal pain.) 50 Computed tomography urogram (CTU) This technique uses a combination of unenhanced, nephrographic and delayed scans following i.v. contrast to sequentially allow examination of renal parenchyma and collecting systems. Suggested protocol includes the following: 1. An oral water load of 500 1000 mL 45 60 min before injection is recommended to ensure a diuresis and collecting system dilatation. No positive oral contrast is given. 2. Patient supine 3. Initial low-dose unenhanced scans of urinary tract (CT KUB) to determine if renal tract calculus disease is present nously. 5. Thin-section (usually 1 mm) scans are obtained from the diaphragm to lower poles of kidneys during the nephrographic/ parenchymal enhancement phase (100 s following start of bolus injection). Alternatively, the scan may instead be acquired during the portal venous phase (70 s), but normal corticomedullary differentiation may make small tumours difficult to appreciate. 6. Delayed thin-section (1 mm) scans are acquired from upper pole of kidneys to bladder base 20 min after contrast injection, to examine collecting systems and ureters. 7. Source images are reviewed along with multiplanar reconstructions. Postprocessing with maximum-intensity projections and surfaceshaded displays may be helpful, especially for demonstration. Variations 51 The nephrographic phase may be omitted if the scan is specifically for urothelial tumour or collecting system assessment. Some protocols use diuretics or abdominal compression bands to achieve collecting system distension. Radiation dose is a significant consideration for a triple-phase CTU (compared with an IVU), but newer iterative reconstruction techniques increasingly available are reducing this. Some authorities advocate the use of a split bolus technique, i.e. 50 mL of i.v. contrast 10 15 min before scanning, with a further 50 mL at the time of the scan, to achieve demonstration of the nephrographic and pyelographic phases in the same acquisition with consequent radiation dose saving. Computed tomography angiography Angiography principles. Indications 1. Renal artery stenosis 2. Renal artery aneurysm, arteriovenous malformation, dissection or thrombosis 3. Delineation of vascular anatomy prior to laparoscopic surgery, e.g. nephrectomy, pyeloplasty Technique 1. No oral iodinated contrast used. 2. Scan from the upper pole of the kidneys to the aortic bifurcation. Modern scanners are fast enough to produce high quality studies of the whole abdomen. 3. Narrow collimation (1 mm). 4. 100 150 mL i.v. contrast medium (LOCM 300) injected at 3 4 Ml 5. Use of bolus tracking/triggering devices or timing test injections is recommended to ensure appropriate timing. Otherwise scans are initiated after a preset empiric delay of 20 25 s from start of contrast material injection. 52 6. Source axial scans are supplemented by multiplanar reconstructions and maximum intensity projection, and volume-rendered surface shaded display postprocessing. 53 Title: MAGNETIC RESONANCE URINARY TRACT Name of the instructor: Target population: 54 Scientific Content: Indications 1. Local staging of prostatic cancer 2. Local staging of bladder cancer 3. Staging of pelvic lymph nodes 4. Renal mass 5. Screening of patients with von Hippel Lindau disease or their relatives, or other genetic conditions 6. MR urography where i.v. or CT urography contraindicated 7. MR angiography: potential living related donors, suspected renal artery stenosis Technique Technique will be tailored to the clinical indication. MR of the kidneys and upper abdomen will generally include T1 and T2 weighted sequences in axial and coronal planes with or without fat saturation; with pre- and postcontrast T1 weighted imaging at 30 and 70 s. MRI of the abdomen and pelvis can be obtained to assess retroperitoneal lymphadenopathy as part of the staging investigations for patients with bladder and prostate cancer, but CT is often used for this purpose with MRI reserved for local staging. MAGNETIC RESONANCE IMAGING OF THE PROSTATE Technique/Example Protocol 1. Patient supine. Phased array body coil. The best images will be obtained with an endorectal coil, but many authorities do not use these. 1.5T or 3T scanners are both used. 3T scanners afford better signal-to-noise ratio, but may be subject to more artifacts notably susceptibility. 2. Antiperistaltic drugs (hyoscine butyl-bromide or glucagon are recommended) 3. T1W and T2W axial scans whole pelvis 55 4. Thin-section (3 4 mm) small field of view T1-weighted spin echo (SE) scans in axial plane orthogonal to the axis of the prostate to evaluate for postbiopsy haemorrhage 5. Thin-section (3 4 mm) small field of view T2-weighted SE scans in transverse, sagittal and coronal planes orthogonal to the axis of the prostate 6. Multiparametric MRI there is increasing use of the following functional studies: (a) Diffusion weighted imaging b values 0, 100 and 800 apparent diffusion coefficient (ADC) map (b) Dynamic contrast-enhanced (DCE) T1W imaging (c) MR spectroscopy citrate, creatine, choline MAGNETIC RESONANCE UROGRAPHY Indications 1. To demonstrate the collecting system/determine level of obstruction in a poorly functioning/obstructed kidney 2. Urinary tract obstruction unrelated to urolithiasis. Suspected renal colic from underlying calculus is better imaged with CT KUB. 3. Congenital anomalies 4. Renal transplant donor assessment (combined with MR angiography) Technique The two most common MR urographic techniques are: -sensitive urography using heavily T2-weighted MRI techniques to visualize fluid-filled structures (equivalent to magnetic resonance cholangiopancreatography [MRCP]) -weighted sequences post gadolinium enhancement 1. Patient supine with an empty bladder for comfort. If the bladder is of interest, a moderately full bladder may be preferred. 56 2. Scout views are obtained. 3. Static MR urography may be performed prior to excretory urography. Thick-slab, single-shot, fast-spin echo or a similar thin-section technique, e.g. half-Fourier rapid acquisition with relaxation enhancement; single-shot, fast-spin echo; singleshot, turbo-spin echo. 3D respiratory triggered sequences may be used to obtain thinsection data sets that may be further postprocessed. 4. Oral or i.v. hydration, compression or diuretics may be used to enhance collecting system distension. 5. Excretory MR urography: a gadolinium-based contrast agent is administered i.v. using a dose of imaged during the excretory phase (10 20 min) using a breath-hold, 3D gradient echo, T1-weighted sequence. Fat suppression will improve the conspicuity of the ureters. T2* effects from a high concentration of contrast agent may reduce the signal intensity of urine and potentially obscure small masses within the collecting system. This can be overcome by using a lower volume of i.v. contrast but may compromise soft-tissue imaging.IC RESONANCE IMAGING OF THE MAGNETIC RESONANCE IMAGING OF ADRENALS Indications Characterization of adrenal mass. Technique Chemical shift imaging: based on a high proportion of intracellular lipid causing alteration of the local magnetic environment within the voxel and hence resonant frequency of protons. Lipid-rich benign adenomas can be shown to lose signal on opposed phase T1W imaging compared with in-phase studies. This is highly specific. Alternatively, unenhanced CT can be used to characterize an adrenal mass as malignant, or 18-F fluorodeoxyglucose positron emission tomography (18-F FDG-PET) can be used to characterize an adrenal mass as malignant. 57 Title: MICTURATING CYSTOURETHROGRAPHY Name of the instructor: Target population: 58 Scientific Content: Indications 1. Vesicoureteric reflux 2. Study of the urethra during micturition 3. Bladder leak post surgery or trauma 4. Urodynamic studies, e.g. for incontinence Contraindications Acute urinary tract infection. Contrast Medium Equipment 1. Fluoroscopy unit with spot film device and tilting table 2. Video recorder (for urodynamics) 3. Bladder catheter Patient Preparation The patient empties their bladder prior to the examination. Preliminary Image Coned view of the bladder. Technique To demonstrate vesico-ureteric reflux (this indication is almost exclusively confined to children): 1. Using aseptic technique, the bladder is catheterized. Residual urine is drained. supine, and bladder filling is observed by intermittent fluoroscopy. It is important that early filling is monitored by fluoroscopy in case the catheter is malpositioned, e.g. in the distal ureter or vagina. 59 3. Intermittent monitoring is also necessary to identify transient reflux. Any reflux should be recorded. 4. The catheter should not be removed until the radiologist is confident that the patient will be able to micturate, the patient does not tolerate further infusion or until no more contrast medium will drip into the bladder. 5. Older children and adults are given a urine receiver, but smaller children should be allowed to pass urine onto absorbent pads on which they can lie. Children can lie on the table, but adults will probably find it easier to micturate while standing erect. In infants and children with a neuropathic bladder, micturition may be accomplished by suprapubic pressure. 6. Spot images are taken during micturition, and any reflux is recorded. A video recording may be useful. The lower ureter is best seen in the anterior oblique position of that side. Boys should micturate in an oblique or lateral projection, so that spot films can be taken of the entire urethra. 7. Finally, a full-length view of the abdomen is taken to demonstrate any undetected reflux of contrast medium that might have occurred into the kidneys and to record the postmicturition residue. 8. Lateral views are helpful when fistulation into the rectum or vagina are suspected. 9. Oblique views are needed when evaluating for leaks. 10. Stress views are used for urodynamic studies. Aftercare 1. No special aftercare is necessary, but patients and parents of children should be warned that dysuria, possibly leading to retention of urine, may rarely be experienced. In such cases a simple analgesic is helpful, and children may be helped by allowing them to micturate in a warm bath. 2. Most children will already be receiving antibiotics for their recent urinary tract infection the dose will usually be doubled for 3 days, starting on the day prior to 60 the procedure. Children not already on antibiotics will also usually be prescribed a 3-day course (often trimethoprim). Complications 1. Urinary tract infection 2. Catheter trauma may lead to dysuria, frequency, haematuria and urinary retention. 3. Complications of bladder filling, e.g. perforation from overdistension; prevented by using a nonretaining catheter, e.g. Jacques 4. Catheterization of vagina or an ectopic ureteral orifice 5. Retention of a Foley catheter 61 Title: ASCENDING URETHROGRAPHY IN THE MALE Name of the instructor: Target population: 62 Scientific Content: Indications 1. Stricture 2. Urethral trauma 3. Fistulae or false passage 4. Congenital abnormalities Contraindications 1. Acute urinary tract infection 2. Recent instrumentation Contrast Medium LOCM 200 reduce the incidence of spasm of the external sphincter. Equipment 1. Fluoroscopy unit and spot film device 2. Foley catheter 8-F. Patient Preparation Consent. Preliminary Image Coned supine posteroanterior (PA) of the bladder base and urethra. Technique 1. Patient supine 2. The catheter is connected to a 50 mL syringe containing contrast medium and flushed to eliminate air bubbles. 3. Using aseptic technique, the tip of the catheter is inserted so that the balloon lies in the fossa navicularis (i.e. immediately proximal to the meatus within the glans), and its balloon is inflated with 2 3 mL of water to anchor the catheter and occlude the meatus. 63 4. Contrast medium is injected under fluoroscopic control, and steep (30 45°) oblique films are taken. Gentle traction on the catheter is used to straighten the penis over the ipsilateral leg and prevent urethral overlap or foreshortening from obscuring pathology. Depending on the clinical indication, ascending urethrography may be followed by descending micturating cystourethrography to demonstrate the proximal urethra and bladder, assuming there is no contraindication to bladder catheterization, e.g. false passage, stricture. It may be possible to fill the bladder retrogradely via the urethral catheter if the patient is able to relax the bladder neck (and thus avoid bladder catheterization). Aftercare None. Complications Due to the Technique 1. Acute urinary tract infection 2. Urethral trauma 3. Intravasation of contrast medium, especially if excessive pressure is used to overcome a stricture 64 Title: RETROGRADE PYELOURETEROGRAPHY& HYSTEROSALPINGOGRAPHY Name of the instructor: Target population: 65 Scientific Content: Indications 1. Demonstration of the site and nature of an obstructive lesion 2. Demonstration of the pelvicalyceal system and potential urothelial abnormalities after previous indeterminate imaging Contraindications Acute urinary tract infection. Contrast Medium HOCM or LOCM 150 small lesions) 10 mL. Equipment Fluoroscopy unit. Patient Preparation As for surgery. Preliminary Image Full-length supine AP abdomen when the examination is performed in the x-ray department. Technique In the operating theatre The surgeon catheterizes the ureter via a cystoscope and advances the ureteric catheter to the desired level. Contrast medium is injected under fluoroscopic control and spot films are exposed. Some form of hard copy or soft copy recording is recommended ideally to the hospital PACS (picture archiving and communication system). 66 In the x-ray department 1. With ureteric catheter(s) in situ, the patient is transferred from the operating theatre to the x-ray department. 2. Urine is aspirated, and under fluoroscopic control, contrast medium is slowly injected. Care should be taken to eliminate air bubbles before injection (as these may mimic pathology such as tumour or calculus). About 3 5 mL is usually enough to fill the pelvis, but if the patient complains of pain or fullness in the loin, the injection should be terminated before this. 3. Images are taken as the catheter is withdrawn. These should include frontal and oblique projections. Aftercare 1. Postanaesthetic observations 2. Prophylactic antibiotics may be used. Complications 1. Pyelosinus extravasation and pyelotubular reflux due to overfilling may result in pain, fever and rigors 2. Introduction of infection 3. Damage or perforation of the ureters or renal pelvis PERCUTANEOUS RENAL CYST PUNCTURE ANDBIOPSYY Indications 1. Diagnostic biopsy: unexplained renal failure, mass, etc. 2. Renal cyst puncture to relieve local symptoms attributable to a cyst Contraindications 1. Bleeding diathesis 2. The possibility of renal hydatid disease 67 Equipment Ultrasound or CT guidance. Patient Preparation Premedication or sedation may be needed. Technique Insertion of the needle can be controlled by either ultrasonography or CT: 1. The patient is placed in the prone position, or as appropriate depending on patient habitus and position of lesion. 2. The kidney, mass or cyst is located directly with US or CT or indirectly, after opacification of the kidneys with i.v. contrast medium. The optimum site for puncture is marked on the skin. For renal biopsy in the investigation of parenchymal disease the lower pole of the left kidney is often preferred. 3. The skin and subcutaneous tissues are infiltrated with 1% lidocaine. 4. The needle is passed directly into the lesion during suspended respiration. US or CT are used to monitor the path of the needle. For cyst puncture, the stilette is removed and the cyst contents are aspirated and examined. 5. For biopsy, the biopsy needle is deployed following confirmation of needle position with imaging. Complications perinephric or haematuria 68 HYSTEROSALPINGOGRAPHY indication 1. Infertility to assess tubal patency 2. Recurrent miscarriages investigation of suspected incompetent cervix, suspected congenital anomaly of uterus 3. Following tubal surgery to establish tubal patency, poststerilization to confirm obstruction and prior to reversal of sterilization 4. Assessment of the integrity of a caesarean uterine scar (rare) Contraindications 1. During menstruation 2. Pregnancy or unprotected intercourse during the cycle 3. A purulent discharge on inspection of the vulva or cervix, or diagnosed pelvic inflammatory disease (PID) in the preceding 6 months 4. Contrast sensitivity (relative) Contrast Medium High osmolar iodinated contrast material (HOCM) or low osmolar iodinated contrast material (LOCM) 27 20 mL. The contrast medium Equipmentshould be prewarmed to body temperature to avoid tubal spasm. 69 Equipment 1. Fluoroscopy unit with spot film device 2. Vaginal speculum 3. Vulsellum forceps 4. Hysterosalpingography balloon catheter 5-F to 7-F. In patients with narrow cervix or stenosis of cervical os, Margolin hysterosalphingography (HSG) cannula may be used. It has a silicone tip and provides tight occlusion of the cervix for contrast injection. Patient Preparation 1. The appointment is made before day 21, or the examination can be booked between the 4th and 10th days in a patient with a regular 28-day cycle. 2. The patient should abstain from unprotected intercourse between booking the appointment and the time of the examination. 3. Apprehensive patients may need premedication. Analgesics before procedure may also help. 4. Informed consent should be obtained. Technique 1. The patient lies supine on the table with knees flexed, legs abducted. 2. The vulva can be cleaned with chlorhexidine or saline. A disposable speculum is then placed using sterile jelly, and the cervix is exposed. 3. The cervical os is identified using a bright light, and the HSG catheter is inserted into the cervical canal. It is usually not necessary to use a Vulsellum forceps to hold 70 the cervix with forceps, but occasionally this may be necessary. The catheter should be left within the lower cervical canal if cervical incompetence is suspected. 4. Care must be taken to expel all air bubbles from the syringe and cannula, as these would otherwise cause confusion in interpretation. Contrast medium is injected slowly into the uterine cavity under intermittent fluoroscopic observation. 5. Spasm of the uterine cornu may be relieved by intravenous (i.v.) Buscopan or glucagon if there is no tubal spill bilaterally. Prewarming the contrast medium to body temperature and injecting slowly may also help avoid tubal spasm. Note: Opiates increase pain by stimulating smooth muscle contraction. Images The radiation dose should be kept as low as possible. Intermittent screening should be performed to the minimal requirement. Images should demonstrate the following: 1. Endometrial cavity, demonstrating or excluding congenital abnormalities or filling defects. 2. Full view of the tubes demonstrating spill. If occluded, show the extent and level of block. 3. If there is abnormal loculation of contrast, a delayed view may be useful. Aftercare 1. It must be ensured that the patient is in no serious discomfort nor has significant bleeding before she leaves. 2. The patient must be advised that she may have spotting or occasional vaginal bleeding for 1 2 days and pain which may persist for up to 2 weeks. 71 3. Prophylactic broad-spectrum antibiotics are routinely given in several centres and are good practice. Complications Due to the contrast medium Allergic phenomena especially if contrast medium is forced into the circulation. Due to the technique 1. Pain may occur at the following times: (a) When using the speculum (b) During insertion of the cannula or inflation of balloon, some patients may have developed vasovagal syncope (c) Uterine or tubal distension proximal to a block or spasm (d) With peritoneal irritation during the following day, and up to 2 weeks 2. Bleeding from trauma to the uterus or cervix 3. Transient nausea, vomiting and headache 4. Intravasation of contrast medium into the venous system of the uterus results in a fine lace-like pattern within the uterine wall. It is of little significance when watersoluble contrast medium is used. Intravasation may be precipitated by direct trauma to the endometrium, timing of the procedure near to menstruation or curettage, tubal occlusion or congenital abnormalities. 5. Infection which may be delayed. Occurs in up to 2% of patients and is more likely when there is a previous history of pelvic infection. 72 Title: PERCUTANEOUS ANTEGRADE PYELOGRPHY AND NEPHROSTOMY Name of the instructor: Target population: 73 Scientific Content: This is the introduction of a drainage catheter into the collecting system of the kidney. Indications 1. Renal tract obstruction 2. Pyonephrosis 3. Prior to percutaneous nephrolithotomy 4. Ureteric or bladder fistulae: external drainage (i.e. urinary diversion may allow closure) Contraindications Uncontrolled bleeding diathesis. Contrast Medium As for percutaneous renal puncture. Equipment 1. Puncturing needle: coaxial needle/catheter set or sheathed 18G needle 2. Drainage catheter: at least 6-F pigtail with multiple side holes 3. Guidewires: conventional J-wire ± extra stiff wire 4. US and/or fluoroscopy usually used in combination Patient Preparation 1. Fasting for 4 h 2. Premedication as required 3. Prophylactic antibiotic Technique Patient position Patient lies prone oblique with a foam pad or pillow under the abdomen to present the kidney optimally. 74 Identifying the collecting system prior to the definitive procedure 1. Freehand or with a biopsy needle attachment; US guidance is the most common method for localizing the kidney and guiding the initial needle puncture into the collecting system. 2. Excretion urography, if adequate residual function and a nondilated system using a parallax technique. 3. Occasionally retrograde injection through an ileal conduit or a ureteric catheter may be used to demonstrate the target collecting system. Site/plane of puncture A point on the posterior axillary line is chosen below the twelfth rib. Having identified the mid/lower pole calyces with US or contrast, the plane of puncture is determined. This will be via the soft tissues and renal parenchyma avoiding direct puncture of the renal pelvis, so that vessels around the renal pelvis will be avoided and the drainage catheter will gain some purchase on the renal parenchyma. There is a relatively avascular plane between the ventral and dorsal parts of the kidney, which affords the ideal access. Techniques of puncture and catheterization The skin and soft tissues are infiltrated with local anaesthetic using a spinal needle. Puncture may then be made using one of the following systems (depending on preference): 1. An 18G sheathed needle, or Kellett needle, using the Seldinger technique for catheterization. Contrast injection is used to confirm successful siting of the needle and for preliminary demonstration of the pelvicalyceal system. On occasion, air is used as a negative contrast medium to enable targeting of a posterior nondependent calyx. Upon successful puncture, a J-guidewire is inserted and coiled within the collecting system; the sheath is then pushed over the wire, which may be exchanged for a stiffer wire. Dilatation is then performed to the size of the drainage catheter, which is then inserted. Care must be taken not to kink the guidewire within the soft 75 tissues. Sufficient guidewire should be maintained within the collecting system, ideally with the wire in the upper ureter to maintain position, and if kinking does occur, the kinked portion of the wire can be withdrawn outside the skin. 2. Coaxial needle puncture systems using a 22/21G puncturing needle that takes a 0.018 guidewire. This affords a single puncture with a fine needle, with insertion of a three-part coaxial system to allow insertion of 0.035 guidewire and then proceeding as in list item (1). 3. The trochar-cannula system, in which direct puncture of the collecting system is made with the drainage catheter already assembled over a trocar. On removal of the trocar, the drainage catheter is advanced further into the collecting system. Having successfully introduced the catheter, it is securely fixed to the skin and drainage commenced. Antegrade pyelography is rarely performed as an isolated procedure; usually it is undertaken following placement of, and via, a nephrostomy catheter, as noted previously. Oblique and AP images are taken with gentle introduction of water-soluble contrast medium. Semierect films may be necessary to encourage contrast medium down the ureters, to show the site and nature of obstruction. Postnephrostomy studies are best performed after a delay of 1 2 days, to allow the patient to recover and be able to cooperate, blood clot to resolve and infected systems to be drained. Aftercare 1. Bed rest for 4 h 2. Pulse, blood pressure and temperature half-hourly for 6 h 3. Analgesia 4. Urine samples sent for culture and sensitivity Complications 76 1. Septicaemia 2. Haemorrhage 3. Perforation of the collecting system with urine leak 4. Unsuccessful drainage 5. Injury to adjacent organs such as lung, pleura, spleen or colon 6. Later catheter dislodgement PERCUTANEOUS NEPHROLITHOTOMY This is the removal of renal calculi through a nephrostomy track. It is often reserved for large complicated calculi, which are unsuitable for extracorporeal shock-wave lithotripsy. Indications 1. Removal of renal calculi 2. Disintegration of large renal calculi Contraindications Uncontrolled bleeding diathesis. Contrast Medium As for percutaneous renal puncture. Equipment 1. Puncturing needle (18G): Kellett (15 20 cm length) or equivalent 2. Guidewires, including hydrophilic and superstiff 3. Track dilating equipment; Teflon dilators (from 7-F to 30-F), metal coaxial dilators or a special angioplasty-type balloon catheter 4. US machine 5. Fluoroscopy facilities with rotating C arm, if possible Patient Preparation 77 1. Full discussion between radiologist/urologist concerning indications and so on 2. Imaging (IVU, CT KUB, CTU) to demonstrate position of calculus and relationship to calyces 3. General anaesthetic 4. Coagulation screen 5. Two units of blood cross matched 6. Antibiotic cover 7. Premedication 8. Bladder catheterization, as large volumes of irrigation fluid will pass down the ureter during a prolonged procedure Technique Preprocedure planning may include a CT KUB and CTU to localize stones and to choose most appropriate access. Patient position As for a percutaneous nephrostomy, usually prone. Methods of opacification of the collecting system 1. Retrograde ureteric catheterization for demonstration and distension of the collecting system may be achieved. In addition, a retrograde occlusion balloon catheter in the ureter will prevent large fragments of stone passing down the ureter 2. Intravenous excretion urography 3. Antegrade pyelography; this also enables distension of the collecting system. Puncture of the collecting system A lower pole posterior calyx is ideally chosen if the calculus is situated in the renal pelvis. Otherwise the calyx in which the calculus is situated is usually punctured. Special care must be taken if puncturing above the twelfth rib, because of the risk of perforating the diaphragm and pleura. Puncture is in an oblique plane from the posterior axillary line through the renal parenchyma. Puncture of the selected calyx 78 is made using a combination of US and a rotating C-arm fluoroscopic facility. On successful puncture, a guidewire is inserted through the cannula, and as much wire as possible is guided into the collecting system. The cannula is then exchanged for an angled catheter, and the wire and catheter are manipulated into the distal ureter. At this stage full dilatation may be performed (single stage) or a nephrostomy tube left in situ with dilatation later (two-stage procedure). Dilatation This is carried out under general anaesthesia. It is performed using Teflon dilators from 7-F to 30-F, which are introduced over the guidewire. Alternatively, metal coaxial dilators or a special angioplasty balloon (10 cm long) are used. A sheath is inserted over the largest dilator or balloon, through which the nephroscope is passed followed by removal of the calculus or disintegration. Removal/disintegration Removal of calculi of less than 1 cm is possible using a nephroscope and forceps. Larger calculi must be disintegrated using an ultrasonic or electrohydraulic disintegrator. Aftercare 1. A large bore soft nonlocking straight nephrostomy tube (sutured) is left in for 24 h following the procedure. 2. Patient care is usually determined by the anaesthetist/urologist. 3. Plain radiograph of the renal area to ensure that all calculi/ fragments have been removed. Complications Immediate 1. Failure of access, dilatation or removal 2. Perforation of the renal pelvis on dilatation 3. Inadvertent access to renal vein and IVC 79 4. Haemorrhage. Less than 3% of procedures should require transfusion. Rarely, balloon tamponade of the tract or embolization may be required. 5. Damage to surrounding structures (i.e. diaphragm, colon, spleen, liver and lung) 6. Problems related to the irrigating fluid Delayed 1. Pseudoaneurysm of an intrarenal artery 2. Arteriovenous fistula RENAL ARTERIOGRAPHY Indications 1. Renal artery stenosis prior to angioplasty or stent placement. Diagnostic arteriography has been replaced generally by MR or CT angiography (MRA or CTA). 2. Assessment of living related renal transplant donors replaced generally by MRA or CTA 3. Embolization of vascular renal tumour prior to surgery 4. Haematuria particularly following trauma, including biopsy. This may precede embolization. 5. Prior to prophylactic embolization of an angiomyolipoma (AML) or therapeutic embolization of a bleeding AML. Contrast medium Flush aortic Selective renal artery injection Equipment 80 1. Digital fluoroscopy unit 2. Pump injector 3. Catheters: injection pigtail 4-F Sidewinder or Cobra catheter Technique Femoral artery puncture For flush aortography, a pigtail catheter is placed proximal to the renal vessels (i.e. approx. T12) and AP, and oblique runs are performed (the oblique run demonstrating the renal origins). Selective catheterization as required is used with appropriate catheters for optimal demonstration of intrarenal vessels, and prior to interventional procedures. 81 Title: Methods of Imaging in the Female Reproductive system Name of the instructor: Target population: 82 Scientific Content: 1. Digital radiography 2. Hysterosalpingography 3. Ultrasonography 4. Computerized tomography (CT) 5. Magnetic resonance imaging (MRI) 6. Minimally invasive procedures (MIP) including biopsies, cyst drainage, angiography, fibroid embolization 7. Positron Emission Tomography (PET)-CT Methods of Imaging the Male Reproductive System (Scrotum and Testes) 1. Ultrasound (US) 2. MRI 3. Radionuclide imaging 4. Venography (including embolization of varices) and angiography HYSTEROSALPINGOGRAPHY Indications 1. Infertility to assess tubal patency 2. Recurrent miscarriages investigation of suspected incompetent cervix, suspected congenital anomaly of uterus 3. Following tubal surgery to establish tubal patency, poststerilization to confirm obstruction and prior to reversal of sterilization 4. Assessment of the integrity of a caesarean uterine scar (rare) S Contraindications 1. During menstruation 2. Pregnancy or unprotected intercourse during the cycle 83 3. A purulent discharge on inspection of the vulva or cervix, or diagnosed pelvic inflammatory disease (PID) in the preceding 6 months 4. Contrast sensitivity (relative) Contrast Medium High osmolar iodinated contrast material (HOCM) or low osmolar iodinated contrast 20 mL. The contrast medium should be prewarmed to body temperature to avoid tubal spasm. Equipment 1. Fluoroscopy unit with spot film device 2. Vaginal speculum 3. Vulsellum forceps 4. Hysterosalpingography balloon catheter 5-F to 7-F. In patients with narrow cervix or stenosis of cervical os, Margolin hysterosalphingography (HSG) cannula may be used. It has a silicone tip and provides tight occlusion of the cervix for contrast injection. Patient Preparation 1. The appointment is made before day 21, or the examination can be booked between the 4th and 10th days in a patient with a regular 28-day cycle. 2. The patient should abstain from unprotected intercourse between booking the appointment and the time of the examination. 3. Apprehensive patients may need premedication. Analgesics before procedure may also help. 4. Informed consent should be obtained.1 84 Technique 1. The patient lies supine on the table with knees flexed, legs abducted. 2. The vulva can be cleaned with chlorhexidine or saline. A disposable speculum is then placed using sterile jelly, and the cervix is exposed. 3. The cervical os is identified using a bright light, and the HSG catheter is inserted into the cervical canal. It is usually not necessary to use a Vulsellum forceps to hold the cervix with forceps, but occasionally this may be necessary. The catheter should be left within the lower cervical canal if cervical incompetence is suspected. 4. Care must be taken to expel all air bubbles from the syringe and cannula, as these would otherwise causeT confusion in interpretation. Contrast medium is injected slowly into the uterine cavity under intermittent fluoroscopic observation. 5. Spasm of the uterine cornu may be relieved by intravenous (i.v.) Buscopan or glucagon if there is no tubal spill bilaterally. Prewarming the contrast medium to body temperature and injecting slowly may also help avoid tubal spasm. Note: Opiates increase pain by stimulating smooth muscle contraction. Images The radiation dose should be kept as low as possible. Intermittent screening should be performed to the minimal requirement. Images should demonstrate the following: 1. Endometrial cavity, demonstrating or excluding congenital abnormalities or filling defects. 2. Full view of the tubes demonstrating spill. If occluded, show the extent and level of block. 3. If there is abnormal loculation of contrast, a delayed view may be useful. Aftercare 1. It must be ensured that the patient is in no serious discomfort nor has significant bleeding before she leaves. 85 2. The patient must be advised that she may have spotting or occasional vaginal bleeding for 1 2 days and pain which may persist for up to 2 weeks. 3. Prophylactic broad-spectrum antibiotics are routinely given in several centres and are good practice. Complications Due to the contrast medium Allergic phenomena especially if contrast medium is forced into the circulation. Due to the technique 1. Pain may occur at the following times: (a) When using the speculum (b) During insertion of the cannula or inflation of balloon, some patients may have developed vasovagal syncope (c) Uterine or tubal distension proximal to a block or spasm (d) With peritoneal irritation during the following day, and up to 2 weeks 2. Bleeding from trauma to the uterus or cervix 3. Transient nausea, vomiting and headache 4. Intravasation of contrast medium into the venous system of the uterus results in a fine lace-like pattern within the uterine wall. It is of little significance when watersoluble contrast medium is used. Intravasation may be precipitated by direct trauma to the endometrium, timing of the procedure near to menstruation or curettage, tubal occlusion or congenital abnormalities. 5. Infection which may be delayed. Occurs in up to 2% of patients and is more likely when there is a previous history of pelvic infection. ULTRASOUND OF THE FEMALE REPRODUCTIVE SYSTEM This can be performed transabdominal (TA) and/or transvaginal (TV). 86 Indications 1. Pelvic mass 2. Pregnancy normal and suspected ectopic 3. Precocious puberty or delayed puberty 4. Pelvic pain 5. Assessment of tubal patency 6. In assisted fertilization techniques 7. Postmenopausal bleeding 8. Menstrual problems, location on intrauterine device (IUD) 9. Ovarian cancer screening Contraindications None. Patient Preparation 1. Transabdominal scan Transvaginal scan full bladder empty bladder 2. Patient consent1 It is advisable to always have a chaperone. Equipment TA 4 10-MHz curvilinear transducers; TV 9 13-MHz endovaginal transducers. Reporting Gynaecological Ultrasound The following format may be useful to assess the female reproductive system: 1. Uterine size in three dimensions. Note any congenital anomalies, presence of fibroids (include size and location) or adenomyosis. 2. Endometrial thickness. Assess relationship with the timing of menstrual cycle namely, trilaminar appearance, presence of polyps. 3. Three dimensional ovarian measurements and volume. Presence of features including polycystic ovaries, significant cysts or mass lesions. Colour Doppler is 87 useful in the assessment of complex adnexal mass lesions, which helps differentiate retracted clot from solid components with blood supply. 4. Comment on adnexae for extraovarian lesions. 5. Examine the cul-de-sac for presence of endometriotic deposits or mass lesions. Note presence of free fluid or ascites. Several software enhancements are available to improve resolution. Tissue harmonic imaging is useful for more definitive evaluation of indeterminate appearances. 3D and 4D ultrasound are also currently widely available and mainly used in obstetric imaging. In gynaecology, 3D endometrial imaging may be useful, but generally adds little clinical value. MRI scan offers more diagnostic value. Contrast Medium Galactose monosaccharide microparticles (Echovist) were used as a specific contrast agent in the assessment of tubal patency (HyCoSy), with spillage of the microparticles into the peritoneal cavity implying patency. This product is no longer available for clinical use. Sonovue (sulphur hexafluoride microbubbles) is not currently licensed for intrafallopian use. Currently a gel containing a mixture of hydroxy ethyl cellulose and glycerol mixed with purified water is used to create a foam (ExEm foam), to perform Hysterosalpingo Foam Sonography (HyFoSy). The foam is injected into the uterine and fallopian tubes, and high-resolution ultrasound images are obtained. Fluoroscopic hysterosalpingography, however, remains the most reliable and safe investigation currently. ULTRASOUND OF THE SCROTUM Indications 1. Suspected testicular tumour 2. Suspected epididymo-orchitis 3. Hydrocele 88 4. Acute torsion. In boys or young men in whom this clinical diagnosis has been made and for whom emergency surgical exploration is planned, ultrasound should not delay the operation. Although colour Doppler may show an absence of vessels in the ischaemic testis, it is possible that partial untwisting resulting in some blood flow could lead to a false-negative examination. 5. Suspected varicocele 6. Scrotal trauma Contraindications None. Patient Preparation Explanation of procedure and verbal consent is usually obtained. Equipment 7.5 15-MHz transducer. Linear array for optimum imaging. Technique 1. Secure environment with patient privacy protected. 2. Patient supine with legs together. Some operators support the scrotum on a towel draped beneath it or in a gloved hand. 3. Both sides are examined with longitudinal and transverse scans, enabling comparison to be made. 4. Real-time scanning enables the optimal oblique planes to be examined. settings should be optimized for the normal side, especially for colour Doppler. Of note, the settings should then not be changed until both sides have been compared. 6. Patient could also be scanned standing upright and a Valsalva manoeuvre can be performed if a varicocele is suspected. 7. Testicular size and volume, echogenicity and presence of focal lesions to be noted. Epididymes are seen posterolaterally. Presence of cysts and inflammatory changes 89 needs to be noted. Also look for hydrocele, evident as free fluid outside the testes in the tunica. 90 Title: COMPUTED TOMOGRAPHY OF THE REPRODUCTIVE SYSTEM Name of the instructor: Target population: 91 Scientific Content: Indications 1. Staging ovarian, endometrial and cervical cancers 2. To evaluate causes of raised CA125 levels 3. In postoperative settings such as evaluation for intestinal obstruction or collections Technique CT staging is usually performed with oral and i.v. contrast. Imaging of the abdomen and pelvis in the portal venous phase is the usual practice in most centres. The thorax may be scanned in the arterial phase, or alternatively single run thorax, abdomen and pelvis may be obtained in the venous phase, which has become more popular in many centres with the advent of faster scanners. CT is mainly used for staging of gynaecological malignancy but also in acute pelvic emergencies. Local staging in endometrial and cervical cancers is better performed with MRI. Characterization of ovarian mass lesions is also best performed with MRI. CT of the thorax, abdomen and pelvis is indicated in endometrial cancers with advanced local disease, aggressive histology and in sarcomas. CT of the abdomen may be indicated in assessment of cephalad extent of nodal disease in cervical cancer. CT of abdomen and pelvis is generally used for staging of ovarian cancer, and to assess nodal disease, peritoneal, omental and diaphragmatic disease. If pleural effusion is present, the thorax should also be imaged. MAGNETIC RESONANCE IMAGING OF THE REPRODUCTIVE SYSTEM Indications 1. Staging of cervical and endometrial cancer 2. Characterization of complex ovarian mass 3. Suspected Müllerian tract anomalies 92 4. Investigation of endometriosis 6. Assessment of pelvic floor 7. Scrotal MRI can be used to further characterize an US-demonstrated mass as intraor extratesticular and to determine the location of intraabdominal undescended testis. 8. Localization and morphology of uterine fibroids prior to consideration for uterine artery embolization Artifacts Artifact from small-bowel peristalsis and, to a lesser extent, colonic peristalsis can occasionally be a problem in the pelvis, and Buscopan 20 mg i.v. can be used to minimize this. Respiratory motion artifact is less of a problem in the pelvis than in the upper abdomen. Movement from anterior abdominal wall fat can be suppressed using a saturation band. Pulse Sequences Multiparametric imaging is used currently in gynaecological malignancies, as in other areas of the pelvis. A combination of T2 weighted images and dynamic contrast enhanced magnetic resonance (MR) images, coupled with diffusion weighted images and apparent diffusion coefficient (ADC) mapping, increases the accuracy of diagnostic interpretation. For midline structures (uterus, cervix and vagina), sagittal T2-weighted spin-echo sequences can be supplemented with further axial sequences angled to regions of interest as required. Inclined axial images perpendicular to the long axis of the uterus or the long axis of the cervix are helpful for uterine and cervical abnormalities, respectively. This technique is also mandatory for accurate local staging of uterine and cervical cancers. The ovaries can be assessed with axial T1-weighted and T2-weighted spinecho sequences in three planes. T1-weighted fatsaturated sequences are used to identify haemorrhage (e.g. within endometriomas) and to help characterize fatcontaining masses. 93 Perfusion imaging of the uterus can be used to assess the effectiveness of uterine fibroid therapy. Diffusion weighted imaging can also be complementary to conventional T2-weighted images in assessing the extent and staging of gynaecological malignancy. Varying B values can be useful to assess restricted diffusion. Generally restricted diffusion is more suggestive of malignancy. MRI is also used to measure the pelvic outlet in pelvimetry, in order to avoid ionizing radiation. Scrotal Magnetic Resonance This is generally performed with the scrotum supported as in US, using a surface coil. High-resolution axial, sagittal and coronal T2-weighted spin echo scans are obtained with a T1-weighted scan to identify haemorrhage. Large field-of-view (FOV) scans should be performed to assess the inguinal canal for the presence of a hernia. Gadolinium i.v. can be given if necessary to assess perfusion. Scans should include the pelvis and kidneys if an undescended testis is being investigated. 94