AbdominalIntermediate 45–60 min

Complete Abdominal Ultrasound

Indication: Abdominal pain; abnormal LFTs; elevated creatinine; abdominal mass; general survey; pre-operative assessment

How to Perform

1
Patient fasting ≥4h. Position supine. Use curvilinear probe (3.5–5 MHz). Begin with gallbladder.
2
Gallbladder: intercostal oblique view (right mid-axillary line). Scan in long and short axis. Roll patient left to confirm stone mobility. Apply direct probe pressure for sonographic Murphy's sign.
3
Measure GB wall (anterior, inner-to-outer) and CBD (inner-to-inner, at porta hepatis anterior to portal vein).
4
Liver: sagittal sweep right to left — assess echogenicity (compare to right kidney cortex), surface contour, size. Measure craniocaudal span at mid-clavicular line.
5
Identify hepatic veins draining to IVC, and portal vein at porta hepatis. Note any dilation, thrombosis, or mass.
6
Pancreas: transverse view at epigastrium, angling inferiorly. Use the splenic vein as a posterior landmark. Survey head (anterior to IVC), body (anterior to aorta), and tail (anterior to left kidney). Note echogenicity and duct size.
7
Spleen: left lateral decubitus or right posterior oblique. Measure maximum craniocaudal length in long axis. Assess echogenicity and parenchymal texture.
8
Right kidney: right flank, coronal view. Measure length in long axis. Assess cortical echogenicity, cortical thickness, central sinus, and collecting system. Grade any hydronephrosis.
9
Left kidney: left flank or posterior approach. Same assessment as right — compare cortical echogenicity to spleen.
10
Aorta: midline transverse at epigastrium. Follow aorta from diaphragm (celiac axis) to bifurcation. Measure outer-to-outer diameter at widest point. Document in TRANSVERSE only.
11
IVC: longitudinal, right of midline. Assess diameter and respiratory variation (collapsed on inspiration = hypovolemia).
12
Bladder: suprapubic transverse and sagittal. Measure three dimensions if post-void volume needed. Note wall thickness and intraluminal contents.

Measurement Guide

Liver Span

Where:Right mid-clavicular line, sagittal view. Place calipers at the dome of the right lobe to the inferior tip.

Normal:≤ 15 cm (mid-clavicular line); > 17 cm = hepatomegaly

Tip:Obtain with patient in inspiration. Ensure the full craniocaudal extent is visible before measuring.

Gallbladder Wall Thickness

Where:Anterior GB wall only, in long axis. Outer wall margin to inner wall margin (where GB lumen begins).

Normal:< 3 mm (fasting); wall ≥ 3 mm + Murphy's + stones = acute cholecystitis

Tip:Measure the ANTERIOR wall only — posterior wall is artifactually thickened by acoustic enhancement from GB bile.

Common Bile Duct (CBD)

Where:At the porta hepatis, anterior to the portal vein, inner wall to inner wall. Use the widest visible lumen.

Normal:≤ 6 mm; ≤ 7–8 mm post-cholecystectomy; add ~1 mm per decade after age 60

Tip:Do not include wall. Scan in intercostal oblique or subcostal approach. If dilated, follow duct distally to identify obstruction level.

Spleen Length

Where:Maximum craniocaudal length in the long axis, coronal view. Dome to inferior tip.

Normal:≤ 12 cm (adults); > 13 cm = splenomegaly

Tip:Left lateral decubitus position improves visualization. Place probe in left posterior axillary line.

Kidney Length

Where:Long axis, maximum pole-to-pole length. Include full extent of renal parenchyma from upper to lower pole.

Normal:9–12 cm (adults); < 8 cm suggests chronic renal disease; asymmetry > 1.5 cm is significant

Tip:Measure in a single sweep from upper to lower pole. Compare both sides. Cortical thickness: normal ≥ 1 cm.

Abdominal Aortic Diameter

Where:Widest transverse diameter, outer wall to outer wall. Measure at the level of maximum dilation.

Normal:< 3 cm; 3–5.4 cm = AAA (monitor); ≥ 5.5 cm = surgical threshold in most guidelines

Tip:Always measure in TRANSVERSE — sagittal views underestimate diameter. Measure at celiac axis, SMA, and just above bifurcation.

Pancreatic Duct

Where:Body of pancreas, transverse view. Lumen of the main pancreatic duct, inner wall to inner wall.

Normal:≤ 2 mm (body); ≤ 3 mm acceptable; > 3 mm = dilation (worry: chronic pancreatitis, pancreatic mass)

Tip:Use the splenic vein as a landmark just posterior to the pancreas body. Fan the probe slightly inferior to see the duct.

Bladder Volume (Post-Void Residual)

Where:Three orthogonal dimensions: transverse width (W), anteroposterior depth (AP), and craniocaudal height (H) — all in cm.

Normal:Post-void residual < 50 mL normal; 50–100 mL borderline; > 100 mL = incomplete emptying

Tip:Formula: Volume (mL) = 0.52 × W × AP × H. Measure immediately after voiding for PVR.

Views to Obtain

Liver — right lobe sagittal (hepatic veins)
Liver — left lobe sagittal + transverse
Gallbladder — long axis
Gallbladder — short axis + Murphy's sign
Common bile duct at porta hepatis
Pancreas — transverse (head, body, tail)
Spleen — long axis (craniocaudal length)
Right kidney — long axis + transverse
Left kidney — long axis + transverse
Aorta — transverse (at celiac, SMA, bifurcation)
IVC — longitudinal
Bladder — transverse + sagittal (post-void if indicated)

What to Look For

Liver echogenicity, size, and surface contour
Gallstones (hyperechoic + posterior shadowing + mobility)
GB wall thickness and pericholecystic fluid
CBD diameter
Pancreatic duct dilation or masses
Spleen size and echogenicity
Kidney size, cortical thickness, hydronephrosis
Aortic diameter (rule out AAA)
Free fluid / ascites in all quadrants

Common Mistakes

Patient must fast ≥4h for GB assessment — contracted GB misses stones
Bowel gas commonly obscures pancreas — scan in various positions or use water as acoustic window
Always measure the aorta in TRANSVERSE — sagittal view underestimates diameter
Kidney echogenicity is relative — compare to liver (right) and spleen (left)
Absent or collapsed IVC suggests hypovolemia

Pro Tip

Start with the gallbladder in the right lateral decubitus position for best distension. Scan the aorta last — patient will often have passed more gas by then.

AI Detects

Cholelithiasis / cholecystitisCBD dilationHepatomegaly / steatosis / cirrhosisSplenomegalyHydronephrosis / renal calculiAAA (aorta >3 cm)AscitesPancreatic duct dilationBladder wall thickening

Start Scan — Abdominal US

Protocol pre-selected · AI will use this context for analysis