AB-Abdomen Abdomen Sonography Examination Questions and Answers

The sonographic image shows a complex fluid collection within the liver parenchyma, with internal echoes and possibly septations, consistent with an abscess. In the clinical context of post-procedural fever following a liver biopsy, a liver abscess is the most likely diagnosis.

A liver abscess appears on ultrasound as a hypoechoic or complex fluid collection that may contain internal debris, septations, or gas (which may produce reverberation artifacts). These features distinguish it from other post-procedural complications.

A cyst (Option A) typically appears as an anechoic, well-defined lesion with posterior acoustic enhancement and no internal debris—this does not match the image or clinical setting.

A biloma (Option B) is a bile collection that can appear similar to a cyst or fluid collection but typically occurs due to bile leak; however, fever and internal complexity on ultrasound more strongly suggest abscess.

A hematoma (Option D) may also appear complex but usually presents with pain and not fever unless secondarily infected. Over time, hematomas evolve in appearance but lack septations and gas unless superinfected.

The ultrasound image demonstrates a dilated duodenum with a hypoechoic soft tissue structure encircling it. This is a classic sonographic appearance suggestive of an annular pancreas. In annular pancreas, pancreatic tissue completely or partially encircles the second portion of the duodenum, which can lead to duodenal narrowing or obstruction.

Annular pancreas is a congenital anomaly that results from failure of the ventral pancreatic bud to rotate properly during embryologic development. As a result, pancreatic tissue encircles the duodenum. It may present in neonates with symptoms of duodenal obstruction or in adults with abdominal pain, pancreatitis, or vomiting.

Ultrasound Findings:

Hypoechoic pancreatic tissue encircling the duodenum

Evidence of duodenal dilatation proximal to the obstruction

“Double bubble” sign may be seen in neonates

Differentiation from other options:

A. Supernumerary kidney: Refers to an accessory kidney. It would be seen in the retroperitoneum and is unrelated to the duodenum or pancreas.

B. Pancreas divisum: A ductal anomaly best diagnosed on MRCP or ERCP. It is not typically visible on conventional ultrasound.

D. Horseshoe kidney: A renal fusion anomaly where the lower poles of the kidneys are fused. It is seen in the pelvis or lower abdomen and does not involve the duodenum or pancreas.

The spleen is almost entirely covered by visceral peritoneum, except at the hilum where vessels, nerves, and lymphatics enter and exit. This area lacks peritoneal covering to allow vascular connection to the splenic artery and vein.

According to Moore’s Clinically Oriented Anatomy:

“The spleen is entirely covered by visceral peritoneum except at its hilum where the vascular structures enter.”

A wandering spleen occurs when the spleen is not adequately anchored by its supporting ligaments, allowing it to move freely within the abdomen. This increases the risk of splenic torsion, which compromises vascular supply and may result in infarction if not corrected.

According to Rumack’s Diagnostic Ultrasound:

“The most serious complication of a wandering spleen is torsion, which may result in splenic infarction.”

Annular pancreas is a congenital anomaly in which pancreatic tissue encircles the second part of the duodenum, potentially causing partial or complete duodenal obstruction (atresia). It is due to abnormal migration of the ventral pancreatic bud.

According to Rumack’s Diagnostic Ultrasound:

“Annular pancreas results from failure of the ventral pancreatic bud to rotate properly, leading to encirclement of the duodenum.”

The normal epididymis typically appears as a homogeneous structure that is either isoechoic or slightly hypoechoic compared to the testis. The most accurate description is "homogeneous compared to the testis," meaning the texture is uniform. It is not anechoic, nor does it typically show irregular borders unless pathology is present.

According to Rumack’s Diagnostic Ultrasound:

"The normal epididymis appears homogeneous and is isoechoic or slightly hypoechoic relative to the testis." (Rumack CM et al., Diagnostic Ultrasound, 5th ed.)

The Doppler ultrasound image shows an elevated peak systolic velocity (PSV) of 637 cm/s, an elevated end-diastolic velocity (EDV) of 312 cm/s, and a low resistive index (RI) of 0.51 at the arterial anastomosis of a renal transplant. These findings are characteristic of significant renal artery stenosis (RAS) at the transplant vascular anastomosis.

Key sonographic features of renal artery stenosis:

Peak systolic velocity (PSV) > 250–300 cm/s at the stenotic segment (this case: 637 cm/s)

Post-stenotic turbulence with spectral broadening

Low resistive index (RI < 0.56 suggests downstream vasodilation)

Elevated acceleration time (AT > 0.07 sec), and reduced acceleration slope

Aliasing on color Doppler due to high velocity

In this image, the marked increase in velocity with spectral aliasing and low RI is diagnostic of transplant renal artery stenosis — the most common vascular complication post-transplant, typically occurring at the site of surgical anastomosis.

Differentiation from other options:

A. Iliac arteritis: A rare condition, not typically presenting with these Doppler changes.

C. Renal vein thrombosis: Would show reversed or absent diastolic flow, not elevated systolic velocities.

D. Arteriovenous malformation (AVM): Produces a high-velocity, low-resistance waveform but is associated with color bruit, aliasing, and pulsatile venous waveforms — not evident here.

A varicocele is an abnormal dilatation of the pampiniform plexus veins, usually seen on the left side due to the perpendicular insertion of the left testicular vein into the left renal vein, making it more susceptible to elevated venous pressure. Sonographically, varicoceles appear as multiple serpiginous anechoic tubular structures that show venous flow on color Doppler, often accentuated with Valsalva maneuver.

Hydrocele (A) is a fluid collection surrounding the testis.

Hematocele (C) is blood within the tunica vaginalis.

Spermatocele (D) is a cystic lesion arising from the epididymis.

Reference Extracts:

Dogra VS, Bhatt S. "Sonographic evaluation of testicular varicoceles." Journal of Ultrasound in Medicine. 2004;23(6): 829-838.

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

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The ultrasound image demonstrates a tubular, anechoic structure coursing anterior to the left portal vein and heading toward the anterior abdominal wall. This is consistent with a recanalized umbilical vein, which is an important collateral pathway that reopens in cases of portal hypertension.

Normally, the umbilical vein becomes obliterated after birth and forms the ligamentum teres. However, in the setting of significant portal hypertension, the umbilical vein may recanalize and serve as a collateral route to decompress the portal system.

Sonographic features of a recanalized umbilical vein:

Anechoic, tubular structure in the ligamentum teres fissure

Seen anterior to the left portal vein

Color Doppler confirms hepatofugal venous flow

Associated with signs of portal hypertension (e.g., splenomegaly, varices)

Differentiation from other options:

A. Budd-Chiari syndrome: Involves hepatic vein outflow obstruction; ultrasound shows absent or narrowed hepatic veins and may have caudate lobe hypertrophy.

B. Splenic artery aneurysm: Typically visualized near the splenic hilum as a pulsatile cystic mass; Doppler shows arterial flow.

D. Median arcuate ligament syndrome: Involves compression of the celiac axis; best assessed with Doppler showing elevated velocities on expiration.

The grayscale ultrasound image demonstrates a uniformly enlarged, hypoechoic (dark), and heterogeneous testis without signs of surrounding scrotal wall thickening or a discrete fluid collection. This pattern is highly suggestive of testicular torsion in the setting of acute scrotal pain.

Sonographic features of testicular torsion on grayscale imaging:

Enlarged testis

Diffusely hypoechoic parenchyma

Loss of normal homogeneity

Absence of internal vascular flow on Doppler imaging (not shown here but critical in confirming diagnosis)

Testicular torsion occurs due to twisting of the spermatic cord, leading to vascular compromise and eventual infarction if not promptly corrected. It is a surgical emergency and typically presents in adolescent males with sudden-onset, severe unilateral testicular pain.

Comparison of answer choices:

A. Scrotal abscess appears as a complex fluid collection with irregular margins and posterior enhancement.

B. Testicular rupture would show discontinuity of the tunica albuginea, heterogeneous texture, and often a hematocele.

C. Testicular torsion — Correct. The enlarged, hypoechoic, heterogeneous testis is characteristic, particularly in the acute phase.

D. Epididymitis typically shows an enlarged, hypervascular epididymis and may extend to the testis (epididymo-orchitis), but vascularity is usually increased rather than absent.

On ultrasound, tendons appear as cord-like hyperechoic structures with linear fibrillar echotexture when imaged in long axis. The fibrils are highly reflective, creating the typical hyperechoic appearance. Posterior shadowing is not typical unless there is calcification.

According to Rumack’s Diagnostic Ultrasound:

“Tendons have a highly organized hyperechoic linear fibrillar pattern when examined along their long axis.”

The ultrasound image labeled “SAG RUQ KIDNEY” demonstrates a midline sagittal view showing a renal parenchymal structure that extends across the midline anterior to the aorta and vertebral bodies, suggesting the presence of a horseshoe kidney.

A horseshoe kidney is a congenital renal anomaly in which the lower poles of both kidneys are fused across the midline by a parenchymal or fibrous isthmus. This isthmus typically lies anterior to the aorta and inferior vena cava and can be seen as a hypoechoic band of tissue crossing the midline on ultrasound.

Ultrasound findings characteristic of a horseshoe kidney:

Abnormally low position of the kidneys in the abdomen

Renal tissue (isthmus) bridging the lower poles anterior to the great vessels

Renal axes may be more horizontal than usual

Kidneys may appear closer together or “kissing” the spine anteriorly

Differentiation from other options:

A. Duplicated collecting system: Manifests as two separate collecting systems within one kidney, often with a central renal sinus split into two — not typically midline bridging.

B. Crossed renal ectopia: Involves one kidney crossing midline and fusing with the other on the opposite side, but they do not form a midline isthmus.

D. Pelvic kidney: A single kidney located in the pelvis due to failed ascent — it does not appear as midline fusion of two kidneys.

Courvoisier sign describes the clinical finding of painless jaundice combined with a palpable, distended gallbladder. This typically results from obstruction at the distal common bile duct, often due to pancreatic head carcinoma or cholangiocarcinoma, leading to bile accumulation and gallbladder distention. In contrast, Mirizzi syndrome involves compression of the common hepatic duct by an impacted stone in the cystic duct.

According to Rumack's Diagnostic Ultrasound and standard clinical references:

“Courvoisier sign refers to a palpable, enlarged gallbladder due to obstruction of the distal bile duct, often from malignancy.”

The ultrasound image labeled “SAG LT KIDNEY MID” demonstrates a left kidney with two separate, centrally located echogenic renal sinuses separated by intervening renal parenchyma. This appearance is classic for a duplicated collecting system.

A duplicated collecting system (also known as duplex kidney) is a congenital anomaly in which a single kidney contains two separate pelvicalyceal systems. It may be complete (with two ureters) or incomplete (partial duplication of ureters). This condition is one of the most common congenital anomalies of the urinary tract.

Sonographic Features of a Duplicated Collecting System:

Two separate central echogenic renal sinus regions seen within one kidney

Intervening parenchyma between the two sinuses

May show associated findings: hydroureteronephrosis (especially of upper pole moiety), ureterocele

Best visualized in sagittal plane

Differentiation from other options:

A. Horseshoe kidney: Shows fusion of the lower poles of the kidneys, typically located anterior to the aorta in the midline—not demonstrated here.

B. Crossed renal ectopia: One kidney is located on the opposite side of the body; this image shows a normally positioned kidney.

C. Prominent renal column (column of Bertin): May mimic a mass, but does not produce two separate sinuses as shown here.

A tumor (such as cholangiocarcinoma, pancreatic head carcinoma, or metastases) is a common cause of biliary duct obstruction. It can compress or invade the bile ducts, leading to intrahepatic and extrahepatic duct dilatation.

Cholecystitis (B) typically affects the gallbladder but may rarely cause duct obstruction if complicated.

Pneumobilia (C) refers to air in the biliary tree, not obstruction.

Hepatitis (D) causes liver inflammation but not mechanical biliary obstruction.

Reference Extracts:

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

Gore RM, Levine MS. Textbook of Gastrointestinal Radiology. 4th ed. Saunders, 2015.

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De Quervain thyroiditis (subacute granulomatous thyroiditis) is often triggered by a viral infection. Patients may present with painful thyroid enlargement, elevated inflammatory markers, and transient hyperthyroidism. Hashimoto’s and Graves' diseases are autoimmune in nature.

According to Braverman’s The Thyroid:

“Subacute (De Quervain) thyroiditis typically follows a viral upper respiratory tract infection and is characterized by thyroid pain and transient thyrotoxicosis.”

Type I choledochal cyst, characterized by fusiform dilatation of the common bile duct, is the most common form, accounting for 80-90% of cases. Other types are much less frequent.

According to Rumack’s Diagnostic Ultrasound:

“Type I fusiform dilatation of the extrahepatic bile duct is the most common type of choledochal cyst.”

Addison disease (primary adrenal insufficiency) results in insufficient production of cortisol and aldosterone. The hallmark laboratory findings include:

Hyponatremia (low sodium)

Hyperkalemia (high potassium)

Elevated liver enzymes (due to nonspecific hepatic involvement)

Fatigue, weight loss, and hypotension are common clinical features.

Conn syndrome (B) causes hyperaldosteronism, leading to hypokalemia (not hyperkalemia).

Acute pancreatitis (C) would typically show elevated amylase/lipase.

Hepatocellular carcinoma (D) may present with elevated liver enzymes but not the electrolyte pattern described.

Reference Extracts:

Nieman LK. "Diagnosis and Treatment of Primary Adrenal Insufficiency." J Clin Endocrinol Metab. 2011;96(7):1957-1966.

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

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Exudative ascites is characterized by high protein content and cellular debris, typically resulting from infections (e.g., peritonitis, tuberculosis), malignancy, or inflammatory conditions. Transudative ascites is more commonly seen in conditions such as liver failure, renal failure, and hypoproteinemia due to changes in hydrostatic or oncotic pressure.

According to Light's Criteria:

“Infection and malignancy are common causes of exudative ascites, distinguished by high protein content and elevated LDH.”

The ultrasound image shows a transverse section through the upper abdomen. The arrow is pointing to a vascular structure running posterior to the pancreas and anterior to the left kidney. This vessel is the splenic vein.

Anatomically:

The splenic vein runs along the posterior border of the pancreas.

It courses medially to join the superior mesenteric vein (SMV) and form the portal vein.

It receives tributaries from the spleen, short gastric veins (draining the stomach), and the inferior mesenteric vein.

In this case, the question asks which organ is primarily drained via the vessel marked by the arrow. The splenic vein's main tributary is from the spleen.

Comparison of answer choices:

A. Spleen — Correct. The splenic vein is the primary drainage vessel for the spleen.

B. Stomach — Some gastric veins drain into the splenic vein, but the primary drainage is via left and right gastric veins into the portal system.

C. Left kidney — Drains into the left renal vein, not the splenic vein.

D. Duodenum — Drains mainly into the superior mesenteric vein (SMV).

Budd-Chiari syndrome is caused by hepatic venous outflow obstruction, resulting in hepatomegaly, ascites, right upper quadrant pain, and liver dysfunction. It may be due to thrombosis or compression of the hepatic veins or IVC.

According to Rumack’s Diagnostic Ultrasound:

“Budd-Chiari syndrome results from hepatic venous outflow obstruction and presents with hepatomegaly, ascites, and right upper quadrant pain.”

The ultrasound image of the thyroid clearly shows posterior shadowing originating from the lateral edges of a rounded structure, which is indicative of edge shadow artifact. Edge shadowing occurs when an ultrasound beam passes tangentially to a rounded or curved structure, such as a cyst or blood vessel. The difference in sound wave refraction and beam divergence at the edges leads to decreased echo signals deep to the edges, creating linear hypoechoic bands — which is exactly what the arrows are pointing to in the image.

Edge shadow artifact is purely a result of beam physics and not a real anatomic or pathologic finding.

Key characteristics of edge shadowing:

Appears as a narrow, linear hypoechoic (dark) shadow extending deep to the edge of a curved interface (e.g., cyst, vessel, thyroid nodule)

Caused by refraction and beam deflection, leading to reduced beam intensity distal to the edges

Most commonly seen adjacent to cysts or fluid-filled structures

Differentiation from other options:

A. Focal enhancement: Appears as increased echogenicity distal to a fluid-filled structure due to lower attenuation of the sound beam through fluid (opposite of shadowing).

C. Speed error: A less common artifact that results in displacement of structures due to variation in assumed sound speed.

D. Comet tail: A reverberation artifact that appears as a series of closely spaced bright echoes, often associated with metallic objects or cholesterol crystals in adenomyomatosis.

Before performing a paracentesis, assessment of the patient's coagulation status is crucial to minimize bleeding risk. The International Normalized Ratio (INR) is the standard lab value used to assess coagulation. Elevated INR may increase the risk of bleeding complications during the procedure. ALT, AFP, and bilirubin levels evaluate liver function or cancer progression but are not directly relevant to bleeding risk for this procedure.

As per AASLD and SIR guidelines:

“An INR and platelet count should be evaluated before paracentesis to assess bleeding risk. Minor elevations in INR (<1.5) may not contraindicate the procedure.” (AASLD Practice Guidance, 2021; SIR Consensus Guidelines, 2019).

The Duct of Santorini is the accessory pancreatic duct that drains the superior portion of the pancreatic head into the minor duodenal papilla. The main pancreatic duct (Duct of Wirsung) drains into the major papilla, often joining the common bile duct at the Ampulla of Vater.

According to Moore’s Clinically Oriented Anatomy:

“The accessory pancreatic duct (Duct of Santorini) may be present and drains into the minor duodenal papilla.”

Chronic rejection presents sonographically as cortical thinning, decreased renal size, and increased echogenicity of the renal sinus fat. Acute rejection typically causes an enlarged, edematous kidney with increased parenchymal echogenicity but preserved size early on.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“In chronic rejection, the allograft becomes smaller with cortical thinning, increased echogenicity, and prominence of the central sinus fat.”

The left lobe of the thyroid is located anterolateral to the esophagus. On transverse ultrasound imaging, the esophagus can often be seen posterior to the left thyroid lobe as a circular structure with echogenic mucosa and hypoechoic muscular layer. The longus colli muscle lies posterior to the thyroid. The thyroid is anterior to the trachea but this refers more to the isthmus or midline portion.

According to Rumack’s Diagnostic Ultrasound:

“The esophagus is seen as a target-shaped structure posterior to the left thyroid lobe; thus, the thyroid lobe is anterolateral to the esophagus.”

The superior mesenteric artery (SMA) is typically visualized surrounded by an echogenic fat pad in the mesentery, producing a characteristic "echogenic ring" appearance on ultrasound. This is a helpful landmark for identifying the SMA in the transverse abdominal aortic plane.

According to Rumack’s Diagnostic Ultrasound:

“The superior mesenteric artery is often seen as a round anechoic structure surrounded by echogenic fat at its origin from the anterior aorta.”

A thyroglossal duct cyst is the most common congenital cystic anomaly in the anterior midline neck. It arises from persistent remnants of the thyroglossal duct, typically located inferior to the hyoid bone.

According to Rumack’s Diagnostic Ultrasound:

“Thyroglossal duct cysts are located in the midline anterior neck and are the most common congenital cystic neck lesions.”

Malignant lymph nodes are often round in shape (short axis/long axis ratio approaches 1), while benign lymph nodes are typically oval (short axis/long axis ratio < 0.5). Rounded shape in post-thyroidectomy patients raises suspicion for metastatic disease.

According to AIUM and ACR Thyroid Imaging Guidelines:

“A rounded lymph node shape is suspicious for malignancy, especially in patients with thyroid cancer.”

Von Hippel-Lindau (VHL) syndrome is a genetic disorder associated with multiple pancreatic cysts, pancreatic neuroendocrine tumors, and other systemic neoplasms. While cystic fibrosis can produce thickened pancreatic secretions, it rarely causes true pancreatic cysts.

According to Rumack’s Diagnostic Ultrasound:

“Multiple pancreatic cysts are strongly associated with Von Hippel Lindau syndrome.”

A common bile duct (CBD) measuring up to 5 mm is considered normal in most patients under age 60. Some references allow for up to 6 mm, especially post-cholecystectomy or in older individuals. Significant dilation (suggestive of obstruction) typically exceeds these measurements.

According to Rumack’s Diagnostic Ultrasound:

“The normal common bile duct measures up to 5–6 mm, with slight increases considered normal after cholecystectomy or with advancing age.”

A full bladder provides an acoustic window that displaces bowel gas and distends the bladder walls, allowing optimal visualization of any bladder masses or lesions. An empty bladder may collapse, obscuring masses.

According to Rumack’s Diagnostic Ultrasound:

“Bladder evaluation should be performed with the bladder optimally distended to visualize its walls and any intraluminal masses.”

The image demonstrates a characteristic "central dot sign" — a hallmark finding of Caroli disease. This is best appreciated on ultrasound as a cystic dilation of the intrahepatic bile ducts with a central echogenic dot or linear structure (which corresponds to the portal vein and fibrous tissue within the dilated duct). The arrow in the image points to one such dilated duct.

Caroli disease is a rare congenital disorder characterized by segmental, saccular dilation of intrahepatic bile ducts. It is often associated with congenital hepatic fibrosis and may predispose to cholangitis, stone formation, and even cholangiocarcinoma.

Key ultrasound features of Caroli disease:

Cystic or saccular dilations of the intrahepatic bile ducts

The "central dot sign" — echogenic focus in the center of the dilated ducts (representing portal vein radicle or fibrous tissue)

May show associated hepatosplenomegaly or signs of portal hypertension

Differentiation from other options:

A. Sclerosing cholangitis: Typically causes diffuse or segmental biliary ductal wall thickening and stricturing; does not present with cystic dilations.

B. Alagille syndrome: A multisystem disorder often characterized by a paucity of intrahepatic bile ducts, not dilation.

D. Biliary atresia: Presents in infancy with obliteration of extrahepatic bile ducts, echogenic "triangular cord" sign, and absence of a visible gallbladder. It does not cause ductal dilation.

In biliary obstruction (such as at the ampulla of Vater), dilation begins proximally and progresses peripherally. The intrahepatic peripheral bile ducts are the last to dilate because backpressure takes time to propagate. Early dilation is typically seen in the common bile duct and common hepatic duct.

According to Rumack’s Diagnostic Ultrasound:

“The intrahepatic peripheral bile ducts dilate last in the setting of progressive biliary obstruction.”

Conn syndrome (primary hyperaldosteronism) results from excessive aldosterone secretion, often due to an adrenal adenoma, leading to hypertension, hypokalemia, and metabolic alkalosis. Cushing disease involves cortisol, Addison disease involves adrenal insufficiency, and Waterhouse-Friderichsen is associated with adrenal hemorrhage.

According to Rumack’s Diagnostic Ultrasound:

“Conn syndrome is due to excessive secretion of aldosterone, often secondary to adrenal cortical adenoma.”

Changing the patient's position allows evaluation of lesion mobility. Blood clots and hematomas are often mobile, while true bladder wall masses remain fixed. This technique helps differentiate between solid masses and non-adherent debris.

According to Rumack’s Diagnostic Ultrasound:

“Changing patient position may distinguish between mobile blood clots and fixed bladder wall masses.”

The mucosa is the innermost layer of the gastrointestinal wall, consisting of epithelium, lamina propria, and muscularis mucosae. It is responsible for absorption and secretion. The submucosa lies just outside the mucosa.

According to Moore’s Clinically Oriented Anatomy:

“The mucosa is the innermost layer of the gastrointestinal tract, responsible for nutrient absorption and secretion.”

Caput medusae refers to dilated paraumbilical veins due to portal hypertension. When portal venous pressure rises, collateral channels may open along the ligamentum teres and recanalized paraumbilical vein, resulting in visible dilated veins radiating from the umbilicus.

Esophageal varices (B) are gastroesophageal collaterals.

Coronary vein varices (C) involve gastric veins.

Splenic vein varices (D) are typically localized to the splenic hilum.

Reference Extracts:

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

Gore RM, Levine MS. Textbook of Gastrointestinal Radiology. 4th ed. Saunders, 2015.

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The ultrasound image shows an anechoic (black) fluid collection in the perihepatic and perirenal spaces. The fluid outlines the liver (LIV) and right kidney (RK), which is characteristic of free fluid in the peritoneal cavity — consistent with ascites.

Sonographic features of ascites:

Anechoic (or hypoechoic) fluid in dependent areas of the abdomen

Seen surrounding the liver, spleen, and intestines

Can be free-flowing or loculated

Bowel loops may be floating or displaced centrally

This image is consistent with a typical finding of ascites: free fluid in Morison’s pouch (hepatorenal recess), a common site for fluid accumulation.

Differentiation from other options:

A. Hydropic gallbladder: Refers to an enlarged gallbladder filled with clear bile; not visible in this image.

B. Hemoperitoneum: May appear similar to ascites, but usually has complex echogenicity or layering if acute; clinical context (trauma, bleeding) is essential for diagnosis.

C. Bowel obstruction: Would show dilated, fluid-filled bowel loops with peristalsis or to-and-fro motion, not evident here.

The structure indicated by the arrow is the middle hepatic vein. This is confirmed by both its anatomical location within the liver and its Doppler waveform characteristics.

Key ultrasound and Doppler features:

The middle hepatic vein runs between the right and left hepatic lobes and drains into the inferior vena cava (IVC). On grayscale imaging, it appears as a tubular anechoic structure extending toward the IVC.

On spectral Doppler, hepatic veins (including the middle hepatic vein) demonstrate a characteristic triphasic waveform due to pressure changes in the right atrium. This triphasic pattern is clearly visible in the Doppler tracing below the image.

This differs significantly from the monophasic low-resistance flow of the hepatic artery or the continuous hepatopetal flow of the portal vein.

Differentiation from other options:

A. Left portal vein: Would show continuous, hepatopetal flow (toward the liver) and lies more anterior and medial within the liver.

C. Proper hepatic artery: Small-caliber vessel with low-resistance pulsatile waveform (not triphasic).

D. Inferior vena cava: Lies posterior to the liver and demonstrates phasic flow with respiration, but this vessel is more centrally located and not shown in this field of view.

Adrenal adenomas are the most common adrenal tumors in adults. They are often discovered incidentally (adrenal incidentalomas) and are usually nonfunctioning, though some may secrete cortisol or aldosterone. Neuroblastoma is common in children, pheochromocytomas are rarer catecholamine-producing tumors, and adrenal cortical carcinoma is malignant but much less common than adenomas.

According to Rumack’s Diagnostic Ultrasound:

“Adrenal adenomas are the most common adrenal masses in adults, frequently identified incidentally on imaging studies.”

The correct sequence of renal arterial branching is: renal artery → segmental arteries → interlobar arteries → arcuate arteries → interlobular arteries. This branching pattern is important for understanding renal perfusion and evaluating vascular disorders.

According to Moore’s Clinically Oriented Anatomy:

“Renal arteries divide into segmental branches, which give rise to interlobar arteries, then arcuate arteries, and finally interlobular arteries.”

The ultrasound image shows a blind-ending, non-compressible, tubular structure in the right lower quadrant with a target or bullseye appearance in transverse section — highly suggestive of the appendix.

Sonographic features of the appendix (especially in suspected appendicitis):

Blind-ending tubular structure arising from the cecum

Non-compressible on graded compression

Diameter >6 mm is suggestive of appendicitis

May demonstrate a “target sign” in transverse view (concentric ring-like appearance)

Increased echogenicity of surrounding fat in cases of inflammation

May contain an appendicolith or show hyperemia on color Doppler if inflamed

The location (right lower quadrant) and appearance in this case are classic for the normal or potentially inflamed appendix.

Differentiation from other options:

A. Fallopian tube: Located more in the adnexal regions and usually not visible unless distended (e.g., hydrosalpinx).

B. Ureter: Usually not visualized on ultrasound unless dilated due to obstruction.

D. Jejunum: Has valvulae conniventes ("keyboard sign") and peristalsis; does not present with a blind-ending tubular appearance from the cecum.

The ultrasound image demonstrates a fluid-filled structure in the posterior knee region, consistent with a Baker cyst (also called a popliteal cyst). A Baker cyst is a synovial fluid-filled sac arising from the posterior medial aspect of the knee joint, typically extending between the medial head of the gastrocnemius and the semimembranosus tendon.

The history of delayed-onset claudication (pain in the calf when walking) two weeks after this image was obtained is strongly suggestive of a ruptured Baker cyst. When a Baker cyst ruptures, synovial fluid may track inferiorly into the calf, producing pain, swelling, and clinical symptoms that mimic deep vein thrombosis (DVT) or arterial insufficiency (e.g., pseudothrombophlebitis syndrome).

Ultrasound findings consistent with a ruptured Baker cyst:

Complex fluid collection tracking along muscle fascial planes (hypoechoic to anechoic)

Posterior calf swelling and tenderness

Absence of thrombus in the deep venous system

Crescent-shaped fluid may be seen between muscle compartments

Why the other choices are incorrect:

A. Neuropathy: Would not show fluid-filled structures on ultrasound and would not present with calf swelling.

B. Infected hematoma: May appear complex, but would require a history of trauma or anticoagulation and systemic signs (fever, redness).

C. Thrombophlebitis: Involves a thrombosed superficial vein with wall thickening and surrounding inflammation, which is not seen in this image.

Power Doppler measures the amplitude (strength) of Doppler signals rather than frequency shift, making it more sensitive to low-velocity and small-vessel blood flow. Its primary advantage is an improved signal-to-noise ratio, allowing for better visualization of slow or weak flow.

A: Power Doppler is more sensitive to motion artifacts, not less.

B: It is still angle dependent, though somewhat less so than color Doppler.

D: Power Doppler does not display flow direction (a limitation).

Reference Extracts:

Kremkau FW. Sonography Principles and Instruments. 9th ed. Elsevier, 2015.

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

Urinomas are collections of urine in the retroperitoneum that result from trauma, surgery, or obstruction causing urine leakage. Trauma is a frequent cause of urinoma formation due to disruption of the urinary tract.

According to Rumack’s Diagnostic Ultrasound:

“Urinomas may develop as a complication of trauma, surgery, or obstructive uropathy with urinary extravasation into the retroperitoneum.”