Renal Cysts and Renal Masses Lecture Notes PDF

‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Renal cysts and renal masses‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫...

‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Renal cysts and renal masses‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Introduction: :‫المقدمة‬ Focal renal masses are commonly identified on imaging studies. Although the most commonly encountered etiology is a benign cyst, a significant subset of renal masses may represent malignant or inflammatory etiologies. Because of the possibility of more sinister etiologies, each renal lesion encountered on imaging needs to be characterized regarding its malignant potential. Ultrasound is a widely available, radiation-free, and relatively inexpensive modality that plays an important role in characterizing focal renal masses. It is used to differentiate benign cysts from solid renal neoplasms, characterize the degree of complexity of renal cysts, and identify features to help differentiate the etiologies of various lesions. In addition, the increasingly widespread availability of contrast-enhanced ultrasound (CEUS) has now provided us the ability to study the enhancement characteristics of renal lesions. When assessing a renal lesion, the first question that a radiologist needs to address is whether it is solid or cystic. The underlying reason for this bifurcation point is that most solid lesions are malignant and treated accordingly. On the other hand, all simple cysts and even most complex cysts are benign. As simple cysts far outnumber all other focal renal lesions, confident characterization of a lesion as a simple cyst can stop any further need for workup in most lesions. The ability to differentiate cysts from solid renal lesions is one of the most important strengths of ultrasound. On ultrasound, renal cysts present as spherical or ovoid anechoic lesions with thin, smooth, or imperceptible walls and posterior acoustic enhancement. The ultrasound waves traverse the fluid within the cyst exceptionally well, resulting in the anechoic appearance of the cyst. Solid lesions, such as lymphoma and renal cell carcinoma (RCC), are sometimes quite hypoechoic but not completely anechoic. Posterior acoustic enhancement is another feature of cysts (and other fluid-filled structures). After traversing the cyst, the relatively unattenuated sound beam results in increased brightness just posterior to the cyst. Pretest: :‫االختبار القبلي‬ What are the differential diagnosis of cystic lesions in the kidney? Scientific Content: :‫المحتوى العلمي‬ Renal cysts When ultrasound shows multiple, echo-free, well circumscribed areas throughout the kidney, suspect multicystic kidney. This condition is usually unilateral, whereas congenital polycystic kidney disease is almost always bilateral (although the cysts may not be symmetrical). Simple cysts can be single or multiple. On ultrasound the walls are smooth and rounded without internal echoes (Fig-11), but with a clearly defined back wall. Such cysts are usually unilocular and, when multiple, will differ in size. Rarely, these cysts become infected or haemorrhage, producing internal echoes. When this occurs or when the outline of any cyst is irregular, further investigation is required. Hydatid cysts usually contain debris and are often loculated or septate.When calcified, the wallappears as a bright, echogenic convex line with acoustic shadowing. Hydatid cysts may be multiple or bilateral. Scan the liver for other cysts and X-ray the chest. If there are multiple cysts in one kidney, the kidney is usually enlarged. This may indicate alveolar echinococcosis. If the patient is less than 50 years old and clinically well, check the other kidney to exclude polycystic disease: congenital cysts are echo-free and without mural calcification. Both kidneys are always enlarged. Fig-11: Longitudinal scan: multiple renal cysts. Renal masses There are two exceptions to the above statement: - In the early stages, a renal angiomyolipoma has ultrasound characteristics that allow accurate recognition. These tumours can occur at any age and may be bilateral. Ultrasound images show a well circumscribed, hyperechogenic and homogeneous mass, and as the tumour grows there will be back wall attenuation. However, some tumours will undergocentral necrosis and there will be strong back wall echoes. At this stage differentiation by ultrasound is no longer possible, but abdominal X-rays may show fat within the tumour, which is unlikely to occur in any other type of renal mass - When a renal tumour spreads into the inferior vena cava or into the perirenal tissues, there is no doubt that the tumour is malignant. Solid renal mass Renal masses may be well circumscribed or irregular and may alter the shape of the kidney. Echogenicity may be increased or decreased. In the early stages, the majority of malignant tumours are homogeneous: if central necrosisoccurs, they become nonhomogeneous. A complex non-homogeneous mass The differential diagnosis of complex masses can be very difficult, but when there is spread of a tumour beyond the kidney, there is no doubt that it is malignant. Malignant tumours may also be contained within the kidney. Both tumours and haematomas may show acoustic shadowing due to calcification. As a tumour grows, its centre may become necrotic with a rough irregular outline and much internal debris, causing a complex ultrasound pattern. The differentiation of this from an abscess or a haematoma can be difficult. The clinical condition of the patient may indicate the correct diagnosis. Tumours can spread into the renal vein or inferior vena cava and resemble thrombosis. A rough, irregular, echogenic mass containing debris within an en- larged kidney may be malignant or a pyogenic or tuberculous abscess. The patient's clinical condition may help to differentiate :‫االختبار البعدي‬ Posttest: What are the differential diagnosis of solid masses in the kidney? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. Burgan, C. M., Sanyal, R., & Lockhart, M. E. (2019). Ultrasound of renal masses. Radiologic Clinics, 57(3), 585-600. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Small kidney, Renal calculi, Trauma, Perirenal fluid‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ :‫المقدمة‬ Introduction: Normally, kidneys are about the size of a fist or 10 to 12 cm (about 5 inches). Kidney atrophy means that the kidney is smaller than normal. This can happen for two basic reasons. The first is that part of the kidney does not develop from birth (called a congenital hypoplasia) making a small kidney. This type of kidney atrophy or small kidney usually does not need any special treatment. The second type happens after birth, which can occur in one or both kidneys. This type of kidney atrophy is due to a lower blood supply to the kidney(s)and/or loss of nephrons, the basic working units of the kidneys. Chronic infections or blockage of the kidney can also result in kidney atrophy. A kidney that is smaller in size can lead to kidney disease. A greater decrease in kidney size, especially for both kidneys, can lead to kidney failure. Urolithiasis refers to the presence of calculi anywhere along the course of the urinary tracts. For the purpose of the article, the terms urolithiasis, nephrolithiasis, and renal/kidney stones are used interchangeably, although some authors have slightly varying definitions of each. Ultrasound is frequently the first investigation of the urinary tract, and although by no means as sensitive as CT, it is often able to identify calculi. Small stones and those close to the corticomedullary junction can be difficult to reliably identify. Ultrasound compared to CT KUB reference showed a sensitivity of only 24% in identifying calculi. Nearly 75% of calculi not visualized were 60% diameter reduction. The commonest causes are atheroma and fibromuscular dysplasia of the vessel wall; other causes include aortic aneurysm, arteritis, emboli, neurofibromatosis and trauma. It is important to make the diagnosis since correction of the stenosis may allow cessation of drug therapy, or at least make therapeutic control easier. In a patient with unilateral renal artery stenosis the affected kidney is usually of normal shape and size unless the stenosis is greater than 60%, when a small decrease in size may be found References: :‫المصادر‬ Paul L. Allan, Grant M. Baxter, Michael J. Weston. Clinical Ultrsound. Elsevier, Volume one; Third edition, 2011. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Normal and abnormal Urinary bladder‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Introduction: :‫المقدمة‬ Indications Dysuria or frequency of micturition. Haematuria (wait until bleeding has stopped). Recurrent infection (cystitis) in adults; acute infection in children. Pelvic mass. Retention of urine. Pelvic pain. Preparation of the patient The bladder must be full. Give 4 or 5 glasses of fluid and examine after one hour (do not allow the patient to micturate). Alternatively, fill the bladder through a urethral catheter with sterile normal saline: stop when the patient feels uncomfortable. Avoid catheterization if possible because of the risk of infection. Normal bladder The full urinary bladder appears as a large, echo-free area arising out of thepelvis. Start by assessing the smoothness of the interior wall of the bladder and its symmetry in transverse section. The thickness of the bladder wall will vary with the degree of distention but should always be approximately the same all around the bladder. Any local area of thickening is abnormal. Look also for trabeculation. When distended, the normal bladder wall is less than 4 mm thick. After scanning, the patient should empty the bladder. Normally, there should be no residual urine: if there is, the quantity should be estimated. Measure the transverse diameter (T) of the bladder in centimeters, multiply it by the longitudinal diameter (L) in centimeters and then by the AP diameter in centimeters. Multiply the total by 0.52. This measures the residual urine in milliliters (cubic centimeters). When the bladder has been thoroughly examined, scan the kidneys and the ureters. Longitudinal scan: normal full bladder Transverse scan: normal full bladder Transverse scan: normal empty bladder Pretest: :‫االختبار القبلي‬ What are the indications of urinary bladder scanning by ultrasound ? Scientific Content: :‫المحتوى العلمي‬ Abnormal bladder It is important to scan for: Variation of the bladder wall thickness and trabeculation. Asymmetry of the bladder. Cystic masses in or outside the bladder (ureterocele or diverticulum). Solid masses within the bladder or at the base of the bladder. Generalized thickening of the bladder wall In men, bladder wall thickening is usually the result of prostatic obstruction. Ifsuspected, check the prostate: exclude hydronephrosis by scanning the ureter and the kidneys. Search for associated diverticula: these project outwards but are only visible if over 1cm in diameter. Diverticula are usually echo-free with good sound transmission. diverticula may collapse or increase in size after micturition. Severe, chronicinfection /cystitis.The inner wall of the bladder may Hypertrophy of the wall of the bladder. Longitudinal scan: diverticulum of the bladder be thickened and irregular. Check the rest of the renal tract for dilatation. Schistosomiasis. The bladder wallsm a y be thickened, with increased echogenicity and scattered dense (bright) areas due to calcification. Very thick trabeculated bladder walls in children may result from outlet obstruction. Athickened bladder wall may occur in a neurogenic bladder and will usually be associated with uretero-hydronephrosis. Two transverse scans showing thickening and irregularity of the bladder wall of a 12-year-old child with schistosomiasis. The left ureter is also thickened (lower). Localized thickening of the bladder wall Whenever localized bladder wall thickening is suspected, multidirectional scans are needed, particularly to exclude a polyp. Moving the patient or increasing the volume of fluid in the bladder will help toidentify bladderfolds. (Folds will disappear as the bladder distends.) Localized thickening may be due to: Bladder fold due to incomplete filling. Tumour. Localized infection due to tuberculosis or to schistosomal plaques (granulomas). Acute reaction to schistosomal infection in children Hematoma following trauma. Differential diagnosis of localized bladder wall thickening Most bladder neoplasms are multiple but located in one area. Some only thicken the bladder wall, but most are also polypoid. It is essential to recognize when the tumour has spread through the bladder wall. Calcification in the tumour or wall due to associated schistosomiasis may cause bright echoes. Bladder polyps are often mobile on a stalk. Granulomas (e.g. tuberculous) cause multifocal but localized. Trauma. If there is localized thickening following trauma, scan the pelvist o exclude fluid (blood or urine) outside the bladder. Schistosomiasis. Children who are reinfected. A sessile polyp in the bladder: longitudinal (left) and transverse (right) scans. Transverse scan: pseudotumour in the bladder, caused by blood clots. Transverse scan: a large malignant tumour arising from the bladder wall. Transverse scan: following injury, there is blood lateral to the bladder, distorting and apparently thickening the bladder wall. References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫العنوان‪:‬‬ ‫المرحلة‪ :‬الرابعة‬ ‫‪Title:‬‬ ‫)‪Abnormal urinary bladder (Density within the bladder and small bladder‬‬ ‫)‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Density within the bladder - Attached to the wall Polyp. A polyp on a long stalk may appear freely mobile. Change the patient's position and rescan. Adherent calculus. Calculi can be single or multiple, small or large: they usually have acoustic shadowing. Some may become adherent to the bladder mucosa, especially when there is infection: scan with the patient in different positions to assess movement. Ureterocele. A ureterocele presents as a cystic mass within the bladder, near a ureteric orifice. It will change in size fi scanned at different times. In children, the ureterocele may be so large that the opposite ureter is also obstructed. Ureteroceles are sometimes bilateral but are seldom symmetrical. If suspected, scan the kidneys and theureters for asymmetrical hydronephrosis and hydroureter, and for duplication of the ureters. Enlarged prostate.Anechogenic,non-mobilemasslocatedcentrally at the base of the bladder in a male patient is most likely an enlarged prostate. In women, an enlarged uterus can also distort the bladder. - Mobile density within the bladder Calculus. Unless they are very large, most calculi move within the bladder. However, calculi may be trapped in a diverticulum. Foreign body. Catheters must be recognized. Very rarely a foreign body is introduced into the bladder. If this is suspected, a careful history is necessary: Xrays may be helpful. Blood clot. A thrombus can resemble a calculus or a foreign body: not all blood clots are freely mobile. Air. Introduced into the bladder either through a catheter or by infection or through a fistula, air appears as an echogenic, mobile, non-dependent (floating) area. Large (overdistended) bladder When distended, thebladder walls will be smooth and evenly stretched, with or without diverticula Use measurements to confirm suspected overdistension. Always look at the ureters and check the kidneys for hydronephrosis. Ask the patient to empty the bladder and rescan to see if it is completelv empty. Common causes of bladder distention are: Enlargement of the prostate. Urethral stricture in the male. Urethral calculus in the male. Bruising of the urethra in the female ("honeymoon urethritis"). Aneurogenic bladder from damage to the spinal cord. Urethral valves or diaphragm in newborn infants. Cystocele in some patients. Small bladder A bladder may be small because of cystitis, which prevents the patient from holding urine and causes a clinical history of frequent and painful micturition. The bladder may also be small because the walls have been damaged or fibrosed, reducing the bladder capacity. Micturition will then be frequent but not painful. A small bladder may be due to: Late schistosomiasis. There may be bright echoes due to calcification. Recurrent cystitis. The rare infiltrating neoplasm. Radiotherapy or surgery for malignancy. Posttest: :‫االختبار البعدي‬ Discuss in details the density within urinary bladder? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Normal and abnormal thyroid gland‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Introduction: :‫المقدمة‬ Indications A palpable mass in the neck. Abnormalities in the carotid arteries (a bruit or symptoms of carotid insufficiency). Doppler ultrasound is needed for a complete assessment. Normal anatomy Ultrasound can demonstrate the following normal structures in the neck: Carotid arteries. Jugular veins. Thyroid gland. Trachea. Surrounding muscles. It is important that all of these structures are located when scanning the neck. Vessels. The vascular bundle (the carotid artery and the jugular vein) is behind and between the sternocleidomastoid muscle and lateral to the thyroid gland. These vessels are very accessible for ultrasonography. The carotid artery, bifurcating into the internal and external branches, will be seen as a tubular structure with hyperechogenic walls and an echo-free centre: the walls are smooth and difficult to compress with the transducer. The jugular vein is lateral to the carotid artery and the walls are more easily compressed. The veins vary in diameter during the different phases of respiration and the Valsalva manoeuvre. Thyroid. The thyroid consists of two lobes, one on either side of the trachea joined in the midline by an isthmus. The thyroid gland and the isthmus have the same homogeneous echo texture, and the lobes should be equal in size. On transverse scans, the section is usually triangular; on longitudinal scans, it is oval. The outline should be smooth and regular (Fig-13). The thyroid gland is normally 15-20 mm thick, 20-25 m m in width, and 30-50 mm in length. Muscles. The sternocleidomastoid muscle is the only muscle of particular importance in pediatric patients. The muscles are band-like structures which are less echogenic than the thyroid. On transverse scans, the outline swell defined but varies from circular to ovoid in section. Lymph nodes. Normal lymph nodes can sometimes be seen as hypoechogenic structures less than 1cm in diameter. Fig-13a: Transverse scan: the common carotid artery, jugular vein, thyroid gland and sternocleidomastoid muscle. Fig-13b: Transverse scan: the common carotid artery, jugular vein, and sternocleidomastoid muscle. Fig-13c: Transverse scan: the normal thyroid gland, including the isthmus Pretest: :‫االختبار القبلي‬ What are the indications of thyroid gland scanning by ultrasound ? Scientific Content: :‫المحتوى العلمي‬ Abnormal thyroid Thyroid abnormalities may be local or diffuse, single or multiple. Focal masses Solid. About 70% of focal lesions are thyroid nodules and over 90% of these will be adenomas, which are very seldom malignant. The ultrasound appearance of an adenoma is variable and it may be impossible to differentiate between a benign thyroid adenoma and a malignant tumour: the ultrasound characteristics are similar, and size is not important. Both benign and malignant tumours can be hypoor hyperechogenic; both may contain cystic components. However, fi the massi swell circumscribed, with asurrounding thin, hypochogenic halo, there is a 95% probability that it is a benign adenoma. When therei s central necrosis, the possibility of malignancy should b econsidered. Cystic. True cysts of the thyroid are rare. Characteristically, they are well circumscribed, with smooth walls, and are echo-free, unless there has been haemorrhage into the cyst. Haemorrhage or an abscess may occur in the thyroid, appearing as a cystic or complex pattern with ill-defined edges. Calcification. Ultrasound shows hyperechogenic areas with distal acoustic shadowing. Thyroid calcification is commonly seen in adenomas, but may occur in malignant tumours. The calcification can be isolated or in clusters, in groups or in chains. It is important to remember that the size of the thyroid nodule and the presence or absence of calcification are not evidence for or against malignancy. Diffuse thyroid lesions Homogeneous enlargement The thyroid may be enlarged, sometimes extending retrosternally. Enlargement may affect only part of a lobe, a whole lobe, the isthmus or both lobes. Enlargement is usually hyperplastic and is ultrasonically homogeneous. It may be due to endemic goitre, lack of iodine, puberty, hyperthyroidism or hyperplasia following partial thyroidectomy. Asmall, homogeneous, hypochogenic thyroid may indicate acute thyroiditis. Heterogeneous enlargement If the ultrasound density of the thyroid is heterogeneous, there are usually multiple nodules (a multinodular goitre); the nodules may be solid o rcomplex onultrasound. I nautoimmune thyroiditis, the thyroid becomes heterogeneous and may resemble a multinodular goitre. Abscess The size and shape of a cervical abscess are very variable,and the outline is often very irregular and unclear. On ultrasound, there are usually internal echoes. In children, abscesses are most commonly in the retropharyngeal region. Adenopathy The diagnosis of enlarged lymph nodes in the neck is usually made clinically, but ultrasound is a satisfactory method of follow-up. On ultrasound, lymph nodes will appear as hypoechogenic masses with regular outlines, solitary or multiple, nodular, oval or round, and variable in size from 1 cm upwards. Ultrasound cannot determine the cause of the lymph node enlargement. Cystic hygromas (lymphangiomas) These are of variable size, are usually situated laterally in the neck, and may extend to the thorax or axilla. On ultrasound they are fluid-filled, often with septa. Less common neck masses In children, echogenic masses may be due to haematoma. In the cervical muscles, a cystic or complex mass may be a thyroglossal cyst (in the midline), a branchial cleft cyst (in the lateral neck) or a dermoid. Vascular abnormalities It is possible with ultrasound to demonstrate atheromatous plaques and show stenosis in the carotid artery, but it is not possible to evaluate blood flow without Doppler ultrasound and, in many cases, angiography. Posttest: :‫االختبار البعدي‬ What are the Less common neck masses? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. ‫لجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫المادة‪ :‬التصوير الموجات فوق الصوتية‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫)‪Thyroid Imaging Reporting and Data System (TI-RADS‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Thyroid Imaging Reporting and Data System (TI-RADS) The Thyroid Imaging Reporting and Data System (TI-RADS) of the American College of Radiology (ACR) was designed in 2017 with the intent to decrease biopsies of benign nodules and improve overall diagnostic accuracy. The five ultrasound features of thyroid nodules used in TI-RADS are as follows: Composition Echogenicity Shape Margin punctate echogenic foci Each item is given point. The points are added from all categories to determine the TI-RADS level, each with a recommendation. Nodules smaller than 5 mm do not need any follow-up, even if they are TI-RADS 5. This is because it is very unlikely that nodules smaller than 5 mm will become a clinical significant malignancy. The cutoff point of 2.5 cm for fine needle aspiration (FNA) in mildly suspicious TR3 lesions is based on studies showing that thyroid carcinomas don’t have a decreased survival until they reach this threshold value. The ACR-TIRADS category has been shown to have good correlation with the malignancy risk in large studies. The risk of malignancy is: TR1: 0.3% TR2: 1.5% TR3: 4.8% TR4: 9.1% TR5: 35% Composition Cystic lesions or lesions that are almost completely cystic are benign and no further points will be added (TI-RADS 1). This is also true for spongiform lesions which are always benign and no further characterization using ultrasound features is needed. Here a typical cyst. No further evaluation is needed. Spongiform nodules have a sponge-like appearance, with at least 50% cystic composition of tiny cystic parts. No further characterization is needed. Spongiform nodules In mixed cystic/solid lesions the amount of cystic and solid parts is not important. This lesion gets 1 point for the mixed cystic/solid composition. Mixed cystic/solid lesions Solid lesions The lesion in A is almost completely solid. While there are small cystic parts, it is not considered a spongiform nodule, because the small cystic parts are far less than 50% of the total nodule. The lesion in B is completely solid. In solid nodules at least 95% of the nodule should be solid. This percentage should be an estimation, it is not needed to calculate this. Solid lesions Echogenicity An anechoic lesion should be completely black, which means that it is cystic. No further characterization is needed. Hyperechoic and isoechoic lesions both get 1 point, so for the score it does not matter. The echogenicity is compared with normal thyroid parenchyma. Hypoechoic means that a lesion is more hypoechoic than normal thyroid parenchyma. If the echogenicity cannot be assed, for example because of calcifications, 1 point is given for the echogenicity. A very hypoechoic lesion is more hypoechoic than normal muscle. Notice that the tumor is more hypoechoic in comparison to the strap muscles (arrows). Very hypoechoic , i.e. 3 points in TI-RADS. Shape The shape should be assesed in the axial plane. A taller-than-wide shape is a strong predictor of malignancy, and therefore gets 3 points. Margin The margin is often best assessed on the anterior side. Smooth: the margin is completely smooth Ill-defined: the margins of the nodule cannot be clearly defined from the thyroid parenchyma. This is a benign feature and should be distinguished from the irregular margin. Lobulated or irregular: margins are lobulated, spiculated, irregular or angulated. Extra-thyroidal extension: difficult to analyze on ultrasound, there should be clear invasion of nearby structures. Bulging of the nodule in nearby structures is not enough. Ill-defined nodule. Notice how only some small parts of the border of the nodule can be defined (arrow). Most of its margin is indistinct from the thyroid parenchyma. (0 points in TI-RADS). A nodule with irregular angulated margins. (2 points in TI-RADS). The image shows an irregular lobulated margin of the anterior surface. (2 points in TI-RADS). There is a nodule which has exophytic growth with compression of the nearby structures. However, there is no frank invasion, there this does not classify as extra thyroidal extension. Echogenic foci Comet tail artefact Echogenic foci is the only category where multiple options are possible and you have to choose all that apply. Points will be added to the total score. This means that when both punctate echogenic foci and rim calcifications are present, the TI-RADS points are 3 + 2 = 5 points 0 points is given for: No echogenic foci. Large comet tail artefacts > 1 mm (figure). Macrocalcification This nodule has large macrocalcifications with acoustic shadowing. (TI-RADS: 1 point). Rim calcification Peripheral rim calcifications can be complete or incomplete. (TI-RADS: 2 points). Microcalcifications Punctate echogenic foci are also knows as microcalcifications. They are a strong predictor of malignancy and therefore get 3 points. The ACR lexicon further defined this category, because in the normal thyroid there also may be echogenic foci visible. Punctate echogenic should be called in the situation where they are obvious and only visible within the nodule. Small comet tail artifacts with a length less than 1mm are also included in this category. (TI-RADS: 3 points). TI-RADS – Thyroid Imaging Reporting and Data System References: :‫المصادر‬ https://radiologyassistant.nl/head-neck/ti-rads/ti-rads#composition-cyst