Brazil: CBR defines kidneys and bladder as the exam scope; ureters/adrenals are reported when abnormal, and post-void residual is added by indication or request. US/Europe: interpret PVR cautiously because thresholds vary across guidance.
Measurements and reference values
Measurement
Usual value
Note
Adult kidney — bipolar length
9–12 cm
varies with height, sex, age and body habitusconsensus normal: 9–12 cmborderline/context: 8–9 ou 12–13 cmlikely abnormal: <8 ou >13 cm✓ applied automatically in the reportSource: StatPearls / Radiology Key / Rumack
Length difference between kidneys
≤ 1,5 cm
larger difference suggests unilateral disease or anatomic variation to correlatenormal: ≤1,5 cmabnormal: >1,5 cmSource: StatPearls / AccessMedicine
Renal parenchyma — thickness
1,3–2,5 cm
less than 1.0 cm is compatible with relevant thinningpreserved: ≥1,3 cmborderline: 1,0–1,2 cmthinned: <1,0 cm✓ applied automatically in the reportSource: PMC Doppler kidney disease / StatPearls
Renal cortex — thickness
7–15 mm
varies by technique; interpret with echogenicity and kidney sizepreserved: ≥10 mmtechnique/age zone: 7–9 mmmarked thinning: <7 mmSource: StatPearls / nephrology ultrasound reviews
Bladder wall — full bladder
≤ 3 mm
3–5 mm depends on filling; >5 mm with a full bladder is suspiciousnormal full: ≤3 mmborderline/filling: 3–5 mmthickened: >5 mm✓ applied automatically in the reportSource: EFSUMB bladder chapter / StatPearls
Bladder volume for evaluation
200–300 mL
partially full bladder improves wall and lesion assessmentSource: EFSUMB bladder chapter
Bladder volume calculation
comprimento × largura × profundidade × 0,52
some protocols use different coefficients depending on bladder shapeSource: StatPearls PVR / bladder volume studies
Post-void residual
<50 (elevado ≥100) mL
no formal consensus (ICS 2016; ICI-RS 2023); the most used binary cut-off is ≥100 mL, and that is what the automatic check applies. The local service protocol is stricter: >30 mL is already recorded as abnormal. Measure soon after voiding and interpret with symptoms and pre-void volume — a single measurement varies widely.normal: <50 mLcontextual zone: 50–99 mLelevated: ≥100 mLinadequate emptying: >200 mLchronic retention (AUA): >300 mL✓ applied automatically in the reportSource: ICS teaching module 2016 / ICI-RS 2023 / EAU / Lukacz 2006 / Milleman 2004 / Wong 2017 / Protocolo local
Classifications and calculators
Post-void residual — consensus reading
Range
Reading
Comment
< 50 mL
Normal
Normal in the literature. The local service protocol is stricter and already records >30 mL as abnormal.
50–99 mL
Contextual zone
Interpret with symptoms and pre-void volume. There is no formal consensus (ICS 2016; ICI-RS 2023).
≥ 100 mL
Elevated residual
Most used binary cut-off in the literature (Lukacz 2006; Milleman 2004; Wong 2017) and the one applied by the automatic check.
> 200 mL
Inadequate emptying
Suggests voiding dysfunction or obstruction, depending on context.
> 300 mL
Chronic retention
AUA uses persistent >300 mL as a volumetric definition of chronic retention.
> 400 mL
Urinary retention
Generally treated as urinary retention.
Use the calculator above with post-void volume in mL. Pre-void volume is optional and calculates residual percentage.
Source: Protocolo local / Ministério da Saúde BR 2020 / ICS teaching module / StatPearls PVR / AUA white paper
Hydronephrosis — ultrasound grading
Grade
Finding
Interpretation
Absent
Nondilated collecting system
Normal when there is no obstructive context.
Mild
Early calyceal/pelvic dilatation, papillae preserved
Real finding, but may depend on hydration, full bladder or variant.
Moderate
Rounded calyces and effaced papillae
Higher suspicion for obstruction; correlate with pain, ureter and ureteric jet.
Severe
Confluent calyces and thinned cortex (<1 cm)
Consensus important abnormality; look for obstructive cause.
Grading is partly subjective; differentiate from extrarenal pelvis and parapelvic cysts.