The Abdomen Sonography Examination (AB-Abdomen)

A urachal cyst arises from incomplete closure of the urachus, a remnant of the fetal allantoic duct connecting the bladder to the umbilicus. It appears as a midline, anechoic, nonvascular mass located between the bladder dome and the umbilicus.

According to Rumack’s Diagnostic Ultrasound:

“A urachal cyst is a midline, anechoic structure located between the bladder and umbilicus, resulting from incomplete obliteration of the urachus.”

A normal renal artery waveform demonstrates rapid systolic upstroke (acceleration) with continuous forward flow in diastole due to the kidney's low-resistance vascular bed. Slow acceleration or blunted peaks may indicate significant renal artery stenosis.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Normal renal artery waveforms demonstrate a rapid systolic acceleration with a sharp systolic peak.”

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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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 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 ultrasound image demonstrates a classic example of ascites, shown by the anechoic (dark) fluid located between bowel loops or surrounding abdominal organs. In this case, there appears to be a small fluid collection in the peritoneal cavity.

One of the key maneuvers used to differentiate free fluid (such as ascites) from loculated fluid or other structures is to reposition the patient. Asking the patient to “turn from side to side” (Option D) can help in assessing whether the fluid shifts position — a hallmark feature of free intraperitoneal fluid. This positional change is highly useful in confirming the diagnosis and distinguishing ascites from other potential mimics (e.g., cystic masses, lymphoceles, or bowel wall thickening).

In contrast:

Drinking water (A) is often used in imaging the urinary bladder or gastrointestinal tract but not for fluid characterization.

Standing upright (B) may shift fluid but is less practical during real-time ultrasound.

Breathing quietly (C) doesn’t significantly aid in visualizing peritoneal fluid mobility.

The ultrasound image demonstrates a dilated common bile duct (CBD), measuring approximately 7.7 mm in diameter. A normal CBD should generally measure less than 6 mm in a patient under 60 years old and may increase approximately 1 mm per decade thereafter or after cholecystectomy.

In the absence of gallstones within the CBD, one of the most concerning causes of CBD dilation is distal obstruction due to an extrinsic compressive lesion. The most common and clinically significant cause of distal CBD obstruction is a mass at the head of the pancreas.

A pancreatic head mass (e.g., adenocarcinoma) may compress the distal CBD and pancreatic duct simultaneously, resulting in the “double duct sign” — dilation of both the CBD and pancreatic duct. This is a classic finding in pancreatic cancer.

Comparison of answer choices:

A. Liver mass — unlikely to cause isolated CBD dilation unless invading the porta hepatis.

B. Cystic duct stone — may cause gallbladder hydrops but typically not CBD dilation unless Mirizzi syndrome is present.

C. Pancreatic head mass — Correct. This is the most likely cause of painless progressive CBD dilation without visible intraductal stones.

D. Gallbladder stones — These may be associated with biliary colic or cholecystitis but typically do not cause CBD dilation unless the stone has migrated and obstructed the distal duct.

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 clinical presentation—tender, swollen breast with erythema and fever—in a lactating female strongly suggests acute mastitis. The sonographic findings support this diagnosis. In the image, the breast parenchyma shows diffuse, hypoechoic, and heterogeneous echotexture with increased vascularity, which is consistent with inflammatory changes typical of mastitis.

Mastitis is a common complication during lactation, particularly in the first few weeks postpartum. It results from milk stasis and subsequent bacterial infection, commonly due to Staphylococcus aureus. Ultrasound features of mastitis include:

Ill-defined, hypoechoic, edematous areas in the breast parenchyma

Increased Doppler flow due to hyperemia

Skin thickening

Ductal dilatation may also be present

If left untreated, mastitis may progress to abscess formation, which would appear as a localized, complex fluid collection with peripheral hyperemia and internal debris. However, the image does not show a well-formed fluid collection consistent with abscess.

Option B (Ductal carcinoma): Inappropriate here due to the acute clinical scenario and patient age. Ductal carcinoma typically presents as a hypoechoic mass with irregular margins and posterior shadowing, not diffuse edema or inflammatory changes.

Option D (Galactocele): This benign milk-filled retention cyst typically appears anechoic or with fluid–fluid levels but lacks signs of inflammation and systemic symptoms such as fever.

Option A (Abscess): This could be a differential, but abscesses usually present with a well-defined anechoic or complex mass. The absence of a discrete collection and the diffuse appearance makes mastitis more likely.