Rad-dex

Recent revisions

Our editorial team continuously reviews the library against authoritative sources. Here are the notable revisions — corrections, sharper framing, and new material. Routine upkeep (dead-link fixes, duplicate merges) isn't listed.

3558

Cards in library

3505

Sources verified

2991

Reference images

0

Reviewed this week

3558

Audited to date

492

Corrections published

What do these numbers mean?
Cards in library:
Total study cards currently available across every section.
Sources verified:
Cards linked to an authoritative reference we've confirmed.
Reference images:
Cards with at least one linked teaching image (e.g. Radiopaedia).
Reviewed this week:
Cards an editor re-checked against sources in the last 7 days.
Audited to date:
Cards an independent reviewer has checked for accuracy and structure.
Corrections published:
Entries in the public updates log where we fixed or sharpened a card.
A fact, cutoff, or label fixed against the source.Framing tightened — a clearer discriminator or teaching point.Substantive new content added.Claims independently re-checked and cited.
QuizHead & NeckRe-verifiedJul 18, 2026

Neck CTA carotid plaque grading

Attached the primary citation supporting the Plaque-RADS 4c odds ratio quoted in the explanation; the figure and confidence interval were independently re-checked against the source study.

FlashcardHepatobiliaryExpandedJul 18, 2026

Radiation LR-TR categories

Completed the radiation treatment response category list to include LR-TR Nonevaluable alongside Viable, Nonviable, and Nonprogressing, and stated the enhancement criterion that separates Nonprogressing from Viable.

ProtocolPhysics & ModalitiesSharpenedJul 18, 2026

CT dose optimization (ALARA)

Added the justification-before-optimization framing and clarified that CTDIvol/DLP are phantom-referenced scanner output metrics while SSDE is the size-corrected patient metric.

QuizNon-interpretive SkillsSharpenedJul 18, 2026

Fetal radiation dose in pregnancy

Rebalanced answer choices so the correct option is no longer the longest and most detailed; answer key unchanged.

QuizNon-interpretive SkillsSharpenedJul 18, 2026

Fetal radiation effects

Rebalanced answer choices to remove length cueing and strengthened the implausible distractor; answer key unchanged.

ProtocolNuclear MedicineCorrectedJul 18, 2026

I-123 MIBG imaging for suspected pheochromocytoma/paraganglioma

Replaced a single vague drug-withdrawal window with the guideline intervals (most agents 24-72 h, labetalol about 10 days), added a preparation/dosing summary, and noted that DOTATATE PET is now the first-line localizer with MIBG reserved for therapy planning.

Source: EANM/SNMMI 2019 practice guideline for radionuclide imaging of phaeochromocytoma and paraganglioma: https://snmmi.org/common/Uploaded%20files/Web/Clinical%20Practice/Procedure%20Standards/2019/EANM%20SNMMI%20guideline%20on%20radionuclide%20imaging%20of%20phaeochromocytoma%20and%20paraganglioma.pdfView card →
ProtocolOB / GYNSharpenedJul 18, 2026

Sonographically indeterminate adnexal mass - O-RADS MRI protocol

Replaced the shorthand curve descriptions with the full O-RADS time-intensity criteria for categories 3, 4 and 5 and flagged that absence of a plateau alone does not separate low risk from high risk; added the missing protocol summary and the b-value units.

DifferentialNeuro · SpineSharpenedJul 18, 2026

Aggressive midline sacral / sacrococcygeal mass in an adult

Added the missing lead-in, which now names solitary-versus-multifocal as the feature separating chordoma from metastasis and myeloma before moving to matrix and lesion epicentre.

QuizBreastCorrectedJul 18, 2026

Benign breast calcification features

Updated the answer and explanation to the current BI-RADS rim descriptor, replacing the retired lucent-centered and eggshell terms and aligning the card with the rest of the breast calcification set.

FlashcardGenitourinarySharpenedJul 18, 2026

Renal angiomyolipoma thresholds

Relabelled the 4 cm and 5 mm figures as heuristics with their key caveat and added the tuberous sclerosis pathway, where mTOR inhibition rather than embolization is first-line.

QuizOncologic StagingSharpenedJul 18, 2026

Deauville PET response scoring

Explanation now labels the score-3 rule as context-dependent and adds the response-adapted de-escalation caveat, aligning it with the topic's complete-metabolic-response card.

AnatomyNon-interpretive SkillsCorrectedJul 18, 2026

Radiation in pregnancy: fetal dose thresholds and counseling

Fetal CT dose range aligned to the ACOG Committee Opinion 723 figure, CNS dose thresholds restated to the published IQ-decrement and severe-disability values, and the "no study exceeds" claim qualified for multiphase and interventional exposures.

QuizNon-interpretive SkillsCorrectedJul 18, 2026

Incidental small solid pulmonary nodule

Explanation corrected at the size boundary: no routine follow-up applies below 6 mm, not at 6 mm or less, and the guideline exclusions were added.

FlashcardNon-interpretive SkillsExpandedJul 18, 2026

Fetal CNS radiosensitivity

One-line answer expanded with the dose thresholds that make the 8-15 week window meaningful and the counseling implication.

FlashcardNon-interpretive SkillsSharpenedJul 18, 2026

Lead-time vs length-time bias

Prompt reworded as a question distinct from the title, and the answer now names disease-specific mortality as the outcome that avoids both biases.

FlashcardNon-interpretive SkillsSharpenedJul 18, 2026

AUC and disease prevalence

Prevalence independence kept but paired with the case-mix (spectrum bias) exception and contrasted with PPV/NPV.

Board pearlNon-interpretive SkillsCorrectedJul 18, 2026

Bosniak classification of cystic renal masses (v2019)

Corrected the class II criteria: under version 2019 calcification of any type is permitted in a thin-walled cyst, replacing the outdated "fine calcification" restriction, and class I now notes that a thin wall may enhance.

FlashcardNon-interpretive SkillsExpandedJul 18, 2026

Radiation cataract lens dose limit

Added the single-year 50 mSv cap that accompanies the 20 mSv five-year average, noted the earlier 150 mSv limit for contrast, and attached the ICRP citation.

Board pearlNon-interpretive SkillsRe-verifiedJul 18, 2026

Diagnostic reference levels (DRLs)

Verified the 75th-percentile DRL and median achievable-dose figures against the ACR-AAPM US CT reference levels and attached the citation.

FlashcardNon-interpretive SkillsRe-verifiedJul 18, 2026

DRL vs achievable dose

Verified the percentile figures against the ACR-AAPM US CT reference levels and attached the citation.

Board pearlNon-interpretive SkillsRe-verifiedJul 18, 2026

Kappa statistic and interobserver agreement

Verified the Landis and Koch agreement bands against the original Biometrics paper and attached the primary citation.

FlashcardNon-interpretive SkillsRe-verifiedJul 18, 2026

Kappa 0.61-0.80

Verified the agreement bands against the original Landis and Koch paper and attached the primary citation.

Board pearlNeuro · SpineSharpenedJul 18, 2026

Fish (codfish) vertebra

Replaced the general-encyclopedia reference with peer-reviewed and case-library sources, and added the caveat that biconcave vertebrae also occur in sickle cell and other marrow-replacing disease rather than osteoporosis alone.

DifferentialGenitourinarySharpenedJul 18, 2026

Hypervascular / avidly enhancing adrenal mass

Added the missing teaser leading with the discriminator between the top two entries, ranked the differential with imaging features, and replaced a mislabeled mnemonic with a pitfalls line.

DifferentialNuclear MedicineSharpenedJul 18, 2026

Functional imaging choice in suspected pheochromocytoma/paraganglioma

Added the missing teaser leading with the SDHB decision point and shortened an unwieldy title.

FlashcardGenitourinarySharpenedJul 18, 2026

Salt-and-pepper sign

Sign is now attributed to its established entity, paraganglioma including head-and-neck lesions, with a note that it indicates hypervascularity rather than a specific tumor.

FlashcardGenitourinaryExpandedJul 18, 2026

Pheochromocytoma pre-procedure blockade

Added the boundary of the rule: alpha-blockade is required before resection but not before IV nonionic contrast CT, with a citation.

FlashcardGenitourinaryCorrectedJul 18, 2026

Pheochromocytoma light-bulb sign

Corrected the stated frequency of T2 hyperintensity and its direction, replaced an unsourced range with a cited figure, and added the false-positive pitfall.

FlashcardGenitourinaryCorrectedJul 18, 2026

Pheochromocytoma rule of 10s

Card recited the rule of 10s as fact; now framed as a legacy heuristic with the hereditary and malignant limbs corrected against current genetics and WHO 2022 terminology.

FlashcardOB / GYNExpandedJul 18, 2026

O-RADS MRI 4 malignancy risk

Added the criteria that earn a category 4 score alongside the risk figure, so the card teaches assignment rather than a bare number.

FlashcardOB / GYNExpandedJul 18, 2026

O-RADS MRI enhancement

Added how the non-dynamic 30-40 s substitute maps to categories 4 and 5 and noted that it cannot separate 3 from 4.

FlashcardOB / GYNExpandedJul 18, 2026

O-RADS MRI categories

Added the published positive predictive values for categories 3, 4 and 5 to match the rest of the topic.

FlashcardOB / GYNSharpenedJul 18, 2026

O-RADS MRI time-intensity curve

Replaced the shorthand curve descriptions with the full three-curve definitions referenced to outer myometrium.

FlashcardOB / GYNSharpenedJul 18, 2026

O-RADS MRI 2 lesions

Added the exception that an endometrioma or dermoid with enhancing solid tissue is no longer category 2.

PaperGenitourinaryCorrectedJul 18, 2026

Pheochromocytoma: An Imaging Chameleon

Replaced an unsourced T2 signal range with the cited figure and corrected its direction, reframed the rule of 10s as a legacy heuristic with current hereditary rates, and added the WHO 2022 metastatic terminology.

EntityGenitourinarySharpenedJul 18, 2026

Pheochromocytoma

Summary now states that T2 signal cannot exclude the diagnosis and adds current WHO terminology and hereditary framing.

ProtocolOB / GYNCorrectedJul 18, 2026

O-RADS MRI dynamic contrast technique for a sonographically indeterminate adnexal mass

Corrected the benign solid-tissue rule to require low signal on both T2 and high-b DWI rather than DWI alone, added the missing summary, and specified how the non-dynamic substitute maps to categories 4 and 5.

PaperOB / GYNRe-verifiedJul 18, 2026

O-RADS MRI Risk Stratification System: Guide for Assessing Adnexal Lesions from the ACR O-RADS Committee

Diagnostic-performance figures re-attributed to the separate multicenter validation cohort with citation; added the curve-to-score mapping and the non-dynamic-protocol caveat.

Board pearlPhysics & ModalitiesCorrectedJul 18, 2026

CT dose metrics: CTDIvol, DLP, SSDE

Corrected the definition of effective diameter to the square root of AP x lateral, added the TG-220 water-equivalent diameter update, attached AAPM Report 96 k-factors, and clarified that SSDE is not an organ dose.

AnatomyPhysics & ModalitiesCorrectedJul 18, 2026

CT dose reference values (adult)

Replaced unsourced typical-dose ranges and an unsupported achievable-dose figure with cited ACR accreditation reference levels and ACR Dose Index Registry values, and added the phantom caveat.

FlashcardPhysics & ModalitiesRe-verifiedJul 18, 2026

Dose length product (DLP)

Attached AAPM Report 96 as the source for the DLP-to-effective-dose k-factors and stated the chest and abdomen values explicitly.

FlashcardPhysics & ModalitiesSharpenedJul 18, 2026

Size-specific dose estimate

Added the TG-220 water-equivalent diameter update and the key limits of SSDE (not an organ dose, no scan-length correction), and replaced a non-authoritative citation.

FlashcardNeuro · SpineSharpenedJul 18, 2026

Chordoma histology

Reframed physaliphorous cells as characteristic rather than diagnostic and named brachyury as the confirmatory marker.

FlashcardNeuro · SpineSharpenedJul 18, 2026

Chordoma origin and location

Softened an absolute claim about midline-only occurrence and added the practical corollary that an off-midline lesion favours chondrosarcoma.

FlashcardGenitourinaryCorrectedJul 18, 2026

AML hemorrhage risk features

Corrected the logic from "size and aneurysm" to independent risk factors, and labelled the 4 cm figure as a heuristic with its main exception.

PaperGenitourinaryCorrectedJul 18, 2026

Spectrum of Renal Angiomyolipoma with Radiologic-Pathologic Correlation

Aligned the hemorrhage-risk size threshold with the classic 4 cm figure used elsewhere in this topic and cited it; expanded the limitation noting the threshold's single-series origin and known challenges.

Board pearlBreastCorrectedJul 18, 2026

BI-RADS calcification distribution and suspicion ladder

Updated superseded descriptors (popcorn, milk of calcium) to the current BI-RADS v2025 lexicon so the card agrees with the other calcification cards, and clarified that morphology outranks distribution in the biopsy decision.

FlashcardBreastCorrectedJul 18, 2026

Suspicious calcification distribution

Removed an unsupported "roughly twice as likely" risk multiplier in favour of qualitative framing, and added the ductal-anatomy rationale.

FlashcardBreastCorrectedJul 18, 2026

DCIS calcifications

Removed a false-precision ">85%" figure; published series report a wide range, so the answer is now qualitative.

FlashcardBreastCorrectedJul 18, 2026

DCIS calcification morphology

Removed an unsourced "~40%" figure and added the defining description of fine pleomorphic plus the contrast with fine linear/branching risk.

DifferentialGenitourinarySharpenedJul 18, 2026

Fat-containing (macroscopic fat) renal mass

Added the missing teaser, leading with calcification as the feature separating angiomyolipoma from fat-containing RCC, and sharpened the liposarcoma entry to the extrarenal-epicentre discriminator.

DifferentialBreastCorrectedJul 18, 2026

Breast calcifications by morphology and suspicion

Added the missing teaser, updated the benign lexicon to BI-RADS v2025 terminology, replaced a force-fit mnemonic with a heuristic carrying its key exception, and removed fixed 4B/4C subcategory labels since BI-RADS assigns none to a morphology; malignancy rates now cited.

Imaging signBreastCorrectedJul 18, 2026

Casting (fine linear / fine linear branching) calcifications

Removed unsourced comedo-correlation figures and the claim that BI-RADS itself assigns 4C to this morphology; substituted a cited malignancy rate and clarified that subcategory is the reader's judgement.

FlashcardGenitourinaryCorrectedJul 18, 2026

Adrenal adenoma HU threshold

Added the missing sensitivity caveat: the 10 HU rule is highly specific but misses the ~30% of adenomas that are lipid-poor, so a value above 10 HU makes a nodule indeterminate rather than non-adenomatous.

FlashcardGenitourinaryExpandedJul 18, 2026

Adrenal washout for adenoma

Added the absolute and relative washout formulas and the 15-minute delayed-phase timing so the threshold is usable at the workstation.

FlashcardCardiacRe-verifiedJul 18, 2026

Cardiac sarcoidosis imaging sensitivity

Re-checked the CMR versus FDG-PET sensitivity figures against the source meta-analysis, attached the citation, and clarified that the two tests are complementary rather than ranked.

Board pearlNuclear MedicineCorrectedJul 18, 2026

Cardiac sarcoidosis FDG-PET

Removed an unsupported suppression-failure percentage in favour of qualitative language, corrected the framing that suppression failure occurs despite adherence, and replaced the vague perfusion wording with the perfusion-metabolism mismatch discriminator.

ProtocolNuclear MedicineSharpenedJul 18, 2026

Cardiac sarcoidosis FDG-PET suppression protocol

Flagged that the consensus considers the benefit of adjunctive unfractionated heparin unclear, and added that diffuse uptake usually indicates failed suppression rather than disease.

FlashcardBreastCorrectedJul 18, 2026

Rim calcifications

Replaced the retired 'lucent-centered' descriptor with the current 'rim' terminology and removed the wall-thickness distinction that BI-RADS no longer recognises.

QuizBreastCorrectedJul 18, 2026

Benign breast calcification morphology

Answer key relabelled from the retired 'lucent-centered' descriptor to the current 'rim' morphology; softened an absolute claim about benignity.