How to Dictate a Renal Ultrasound: A Model Report for Residents

Nobody formally teaches dictation. You absorb it by imitation, which means you also absorb every bad habit of whoever you happen to imitate. The renal ultrasound is the right study to learn structure on: short, common, and with a finite list of things that must be said about each organ.

The structure

Fixed subsections, every time, even when normal:

• Right kidney: size, echogenicity, cortical thickness, hydronephrosis, stones, masses
• Left kidney: the same, independently — never "kidneys are..."
• Bladder: wall, contents, post-void residual when obtained

Separate sides matter because pathology is usually asymmetric and because a reader scanning for the left kidney should find a labeled line, not a shared sentence.

The numbers that belong in every report

• Renal length, both sides, in centimeters. Normal adult range is roughly 9–12 cm; a >2 cm side-to-side discrepancy deserves a sentence even when both are "normal."
• Cortical echogenicity relative to liver (right) or spleen (left). "Echogenic kidneys" without the comparison is an opinion; "cortical echogenicity greater than the adjacent liver" is a finding.
• Post-void residual, calculated, in milliliters — with the pre-void volume if retention is the question.

Hydronephrosis: grade it, and grade it honestly

Mild — calyceal blunting with preserved cortex. Moderate — rounded calyces, medulla effaced. Severe — ballooned collecting system with cortical thinning. Two traps produce most of the overcalls:

1. An extrarenal pelvis is a normal variant: a prominent pelvis outside the renal sinus with normal calyces is not hydronephrosis.
2. Parapelvic cysts mimic a dilated collecting system on a single image; they do not connect. If the "hydro" doesn't communicate, say cysts.

And the corollary: a non-dilated system does not exclude obstruction in the acutely dehydrated or early stone patient. Correlate with the clinical question rather than declaring the ureter innocent.

Stones, cysts, and the Bosniak question

For stones, report the echogenic focus, its shadowing, and — if color Doppler was used — the twinkle artifact; give a size for anything that will need urology's attention.

For cysts, ultrasound's job is one binary: simple or not simple. A simple cyst (anechoic, imperceptible wall, posterior enhancement, no nodularity) needs nothing further and should be called benign without hedging. Anything else — septations, mural thickening, nodularity, internal echoes that aren't clearly hemorrhagic — is "not characterized by ultrasound," and the report should route it to contrast-enhanced CT or MRI, where the Bosniak 2019 classification applies. Do not assign a Bosniak class from grayscale ultrasound alone; the system is defined on contrast-enhanced imaging, and what changed in the 2019 revision makes enhancement even more central. The honest ultrasound sentence is: "Complex left renal cyst with internal septations, incompletely characterized; recommend renal-protocol CT or MRI for Bosniak classification."

The phrases attendings correct

• "Medical renal disease" as a reflex for any echogenic kidney — describe the echogenicity and cortical thickness instead, and let the impression say "findings suggest chronic renal parenchymal disease" only when they do.
• "Unremarkable" for a kidney you didn't measure.
• "Trace hydronephrosis" — grade it or don't call it.
• Repeating the findings as the impression. The impression answers the clinical question in numbered lines: is there hydronephrosis, is there a stone, is there a mass, what happens next.

A model report

EXAMINATION: Ultrasound kidneys and bladder HISTORY: 58-year-old male, flank pain. TECHNIQUE: Grayscale and color Doppler evaluation of the kidneys and bladder. COMPARISON: None. FINDINGS: Right kidney: 10.8 cm. Normal cortical echogenicity and thickness. Mild hydronephrosis with a 6 mm shadowing echogenic focus at the right ureteropelvic junction, with twinkle artifact. No mass. Left kidney: 10.4 cm. Normal echogenicity. No hydronephrosis, stone, or mass. 2.1 cm simple cortical cyst, lower pole. Bladder: Normal wall. No calculus. Post-void residual 18 mL. IMPRESSION:

1. 6 mm obstructing right UPJ calculus with mild right

hydronephrosis.

1. Simple left lower-pole renal cyst — benign, no

follow-up needed.

Every line of that model earns its place, every number is stated, and the impression makes a decision. Structure like this is also exactly what reporting software should produce for you rather than from you — watch a renal case draft itself in the live demo, or start with the free calculators your attendings will quiz you on.