Renal and Thyroid Ultrasound PDF

Renal cyst and renal mass Small kidney,renal calculi, trauma and peri renal fluid Prepared by Dr.Mahabad Naqishbandi ABHS(Radiology) This Photo by Unknown Author is licensed under CC BY-NC-ND Focal renal mass Focal renal masses are commonly identified on imaging studies. Although the most commonly e...

Renal cyst and renal mass Small kidney,renal calculi, trauma and peri renal fluid Prepared by Dr.Mahabad Naqishbandi ABHS(Radiology) This Photo by Unknown Author is licensed under CC BY-NC-ND Focal renal mass 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. Ultrasound is a widely available, radiation-free 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. Why to use ultrasound? 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. 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. How does simple cyst look like? 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 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 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. Renal masses Renal Angiomyolipoma 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 tumor grows there will be back wall attenuation. However, some tumors will undergo central 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 tumor, which is unlikely to occur in any other type of renal mass Malignant renal mass A complex non-homogeneous mass The differential diagnosis of complex masses can be very difficult, but when there is spread of a tumor beyond the kidney, there is no doubt that it is malignant. contained within the kidney. Both tumors and hematomas may show acoustic shadowing due to calcification. a complex ultrasound pattern( The differentiation of this from an abscess or a hematoma can be difficult.). Tumors 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 Small kidney 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 no 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 Chronic infections blockage of the kidney can also result in kidney atrophy. ref Small Kidney normal echogenicity may be due to renal artery stenosis or occlusion, or to congenital hypoplasia. normal in shape but hyperechogenic, may indicate chronic renal disease. In renal failure, both kidneys are likely to be equally affected. A small, hyperechogenic kidney with an irregular, rather "rough" outline and variable thickness of the cortex (usually bilateral but often very asymmetrical) is probably the result of chronic pyelonephritis or infection such as tuberculosis. A single, small, normally shaped but hyperechogenic kidney may be due to end - stage renal vein thrombosis. Acute renal vein thrombosis usually causes renal enlargement, with shrinkage occurring later. Chronic obstructive nephropathy can affect one kidney in the same way, but chronic glomerulonephritis is usually bilateral. Renal Calculi Urolithiasisers to the presence of calculi anywhere along the course of the urinary tracts. 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 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). Punctate echogenic foci are also known as microcalcifications. They are a strong predictor of malignancy and therefore get 3 points. Microcalcifications 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. Microcalcifications 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 Thank you Prepared by Thyroid ultrasound Dr.Mahabad Naqishbandi ABHS(Radiology) Normal anatomy Ultrasound can demonstrate the following normal structures in the neck: Carotid arteries. Jugular veins. Thyroid gland. Trachea. Surrounding muscles. Important structure to scan 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 maneuver. Thyroid look 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 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 outlines are well 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. Transverse scan: the common carotid artery, jugular vein, thyroid gland and sternocleidomastoid muscle. Transverse scan: the common carotid artery, jugular vein, and sternocleidomastoid muscle. Transverse scan: the normal thyroid gland, including the isthmus 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 hypo- or hyperechogenic; both may contain cystic components. However if the mass is well circumscribed, with a surrounding thin, hypochogenic halo, there is a 95% probability that it is a benign adenoma. When there is central necrosis, the possibility of malignancy should be considered. 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. Focal abnormality Thyroid 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. Causes: endemic goiter, lack of iodine, puberty, hyperthyroidism or hyperplasia following partial thyroidectomy. If the ultrasound density of the thyroid is heterogeneous, there are usually multiple nodules (a multinodular goitre); the nodules may be solid or complex on ultrasound. Heterogeneous enlargement In autoimmune thyroiditis, the thyroid becomes heterogeneous and may resemble a multinodular goitre. Small thyroid Asmall, homogeneous, hypochogenic thyroid may indicate acute thyroiditis. 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 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 abnormalities Hematoma echogenic masses 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. Thank you