Medical Mnemonics
Radiodiagnosis Mnemonics
Radiodiagnosis rewards a systematic eye and a firm grasp of physics, and the mnemonics here support both. They cover radiation protection, Hounsfield and Doppler conventions, the trauma and stroke signs that must be spotted quickly, and the reporting systems that standardise practice. Several hold the numeric thresholds examiners love, from Bosniak categories to the adrenal 10 HU rule. Use each acronym to organise a search pattern or a differential you already understand, not to skip the reasoning. Recognising a hyperdense middle cerebral artery or a positive trauma scan early can redirect the whole management pathway. Each entry maps to a core NMC competency.
MedNext Academy | 3 min read
Radiodiagnosis Mnemonics
Radiodiagnosis rewards a systematic eye and a firm grasp of physics, and the mnemonics here support both. They cover radiation protection, Hounsfield and Doppler conventions, the trauma and stroke signs that must be spotted quickly, and the reporting systems that standardise practice. Several hold the numeric thresholds examiners love, from Bosniak categories to the adrenal 10 HU rule. Use each acronym to organise a search pattern or a differential you already understand, not to skip the reasoning. Recognising a hyperdense middle cerebral artery or a positive trauma scan early can redirect the whole management pathway. Each entry maps to a core NMC competency.
Radiodiagnosis rewards a systematic eye and a firm grasp of physics, and the mnemonics here support both. They cover radiation protection, Hounsfield and Doppler conventions, the trauma and stroke signs that must be spotted quickly, and the reporting systems that standardise practice. Several hold the numeric thresholds examiners love, from Bosniak categories to the adrenal 10 HU rule. Use each acronym to organise a search pattern or a differential you already understand, not to skip the reasoning. Recognising a hyperdense middle cerebral artery or a positive trauma scan early can redirect the whole management pathway. Each entry maps to a core NMC competency.
Mnemonics and expansions
- **ALARA:** As Low As Reasonably Achievable. The guiding principle of radiation dose optimisation for every exposure.
- **TDS:** Time, Distance, Shielding. The three practical ways to reduce radiation exposure; dose falls with the square of distance.
- **FABC:** Fat minus 50 to minus 100, Air minus 1000, Blood (acute) 50 to 70, Cortical bone 1000. Reference Hounsfield unit anchors for reading a CT (water is 0).
- **BART:** Blue Away, Red Toward. The colour Doppler convention for flow direction relative to the transducer.
- **FAST:** Right upper quadrant, Left upper quadrant, Pelvis, Subxiphoid (pericardium). The focused trauma scan; a positive result in an unstable patient means laparotomy without waiting for CT.
- **Hyperdense MCA sign:** The occluded middle cerebral artery appears brighter than the opposite side because of thrombus. The earliest CT sign of acute MCA stroke, present before any parenchymal change.
- **Bosniak 1 to 4:** I and II benign, IIF follow up, III excise (about half malignant), IV malignant. Classifies renal cysts and guides whether to watch or resect.
- **BI-RADS 0 to 6:** 0 incomplete, 1 negative, 2 benign, 3 probably benign, 4 suspicious, 5 highly suggestive, 6 known cancer. Standardises mammography reporting; category 4 and above needs a biopsy.
- **RECIST 30-20:** Partial response is a 30 percent decrease, progression a 20 percent increase in summed target lesion diameters. The response criteria used to track solid tumours on imaging.
- **Adrenal 10 HU rule:** An adrenal nodule under 10 HU on unenhanced CT is a lipid-rich adenoma; over 10 HU needs further characterisation. The first step in working up an adrenal incidentaloma.
- **SLIPPERS:** Spermatogonia, Lymphocytes, Intestinal crypt cells, Precursors, Proliferating basal cells, Endothelium, Resting cells, Slow-turnover cells. Ranks cell types from most to least radiosensitive; lymphocytes are sensitive despite not dividing.
- **kVp quality, mA quantity:** Kilovoltage peak sets beam energy and penetration; milliamperage sets the number of photons. Explains which exposure factor changes contrast and which changes noise and dose.
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