Radiology Calculator Hub

Guideline-based reference tools · References checked 12 October 2026

Clinical decision supportVerify inputs, guideline scope and recommendations with a qualified clinician and local policy. This file has not received independent clinical validation or ACR endorsement. No patient identifiers are requested.

Adult eGFR & renal contrast guidance

CKD-EPI 2021, race-free. Select the clinical context before interpreting the estimate. This is not a complete contrast screening or authorization tool.

Combined is generally preferred when both standardized measurements are available; assess important non-GFR influences on either marker.

Check the selected unit against the laboratory report.

Kidney context
Scope, limitations and references

Adults ≥18 only. Estimates need standardized assays and clinical interpretation. One result does not establish CKD: chronicity and other kidney findings matter. Pregnancy, unusual muscle mass and other non-GFR determinants require clinician interpretation. Display rounding is separate from decision comparisons.

Group II is a risk classification, not a synonym for macrocyclic structure. Metformin instructions here follow ACR; local policy and product labeling must also be considered.

References checked 12 October 2026. Clinical deployment requires local review.

ACR TI-RADS

2017 scoring system, with the currently posted ACR chart, reporting template and FAQ checked on 12 October 2026. Enter one thyroid nodule’s ultrasound findings. Management is limited to the adult context assessed below.

Use the largest of the three measured dimensions. Thresholds use the entered size without rounding.

1. Composition

Spongiform means small cystic spaces occupy more than half the nodule. Either zero-point composition is TR1 without scoring the remaining ultrasound features.

2. Solid-component echogenicity

For mixed nodules, assess the solid component. Very hypoechoic means darker than the adjacent strap muscles.

3. Shape in the transverse plane
4. Margin
5. Echogenic foci

Add every applicable scored type, once each. For example, rim calcification plus punctate foci adds 5 points. The zero-point comet-tail pattern is large (>1 mm) in a cystic component; small tails can accompany punctate foci.

Clinical context for management

Examples: suspicious cervical nodes, known thyroid cancer, relevant symptoms, or limited life expectancy.

ACR sources and interpretation notes

ACR TI-RADS current resource page · Assessment chart · Reporting template and surveillance intervals · ACR FAQ, updated 12 January 2026.

For serial studies, compare current and earlier measurements. Significant growth is an increase of at least 20% in two dimensions with at least 2 mm absolute increase, or at least 50% in volume. Growth and changes in category require review of the surveillance plan. For multiple nodules, assess each and prioritize no more than two for biopsy by their TI-RADS category rather than size alone. ACR measure specification, TI-RADS details. Ultrasound definitions: ACR atlas.

Fleischner 2017 — Incidental Solid Nodules

Initial management reference for indeterminate solid pulmonary nodules. This is a Fleischner Society guideline, separate from ACR contrast guidance. Ground-glass and part-solid pathways are not implemented here.

Enter the radiologist's mean of long and short axes, rounded to the nearest whole millimeter. For multiple nodules, enter the largest mean diameter. The size bands are <6, 6–8 (including 8), and >8 mm. Review thin-section images and prior scans.

The most suspicious nodule can be smaller than the largest. Its individual assessment can change management.

Consider smoking, age, nodule appearance and location, exposures, family history, emphysema and fibrosis together.

Sources and scope

Fleischner Society 2017 management guideline · Measurement statement · 2024 thoracic glossary.

The Society's publication index was checked on 12 October 2026; it lists the 2017 nodule management guideline. The 2024 glossary is a terminology update.

Intervals are measured from the baseline CT. Review the complete guideline and radiology report before ordering follow-up. This tool does not diagnose malignancy or determine whether contrast is appropriate.

PI-RADS v2.1

Combine radiologist-assigned sequence scores for one lesion. ACR’s current-release link was checked on 12 October 2026 and points to version 2.1 (2019).

Official sources

ACR PI-RADS current-release page · PI-RADS v2.1 full criteria (printed pp. 10–11, 15–20, 23) · Official v2.1 changes.