Adrenal lesion characterization by washout on a three-phase CT

Characterization of adrenal masses that are less than 3cm in diameter can be achieved by calculating its washout on a three-phase CT acquisition (unenhanced, venous, and delayed phase). It does not apply to masses that have a specific appearance such as myelolipoma (fat attenuation). Lesions with attenuation ≤10HU on unenhanced scan are lipid-rich adenomas.

Estimate of spleen volume on CT or MRI, splenic index - calculator

This formula can be used to estimate volume of the spleen on crossectional imaging methods by measuring three dimensions - caudocranial (L), maximum size in axial plane (D), and maximum thickness in axial plane (T).

Splenic index = L x D x T
A normal value is considered ≤480.

Volume [mL] = 30 + 0.58 x L x D x T
A normal value is considered between 110 and 340mL

Maximum allowable contrast dose in adults - calculator of MACD

In healthy adult individuals, the maximum allowable volume of intravenous iodine contrast is:
≤300mL (with concentration 300mg I/mL).
In patients with renal insufficiency in particular, the volume of the contrast should be as low as reasonable. However, it should not exceed
440 x weight [kg] / creatinine [µmol/L] mL
5 x weight [kg] / creatinine [mg/dL] mL
(with concentration 300mg I/mL).

Estimate of liver volume on CT or MRI - calculator

This formula can be used to estimate volume of the liver on crossectional imaging methods by measuring its maximum dimension in three perpendicular axes - caudocranial (CC), latero-lateral (LL), antero-posterior (AP). A normal value is considered <2000mL.

Volume = CC x LL x AP x 0.31

Intracranial aneurysm - description of size and neck + calculator

Apart from giving the dimensions of an intracranial aneurysm, its size should be cathegorized according to this table.

Description Size
Small ≤5mm
Medium <15mm
Large <25mm
Giant ≥25mm

The diameter of the neck of the aneurysm is cathegorized as well.

Description Size

Doubling time - calculation of growth rate of a lesion or a mass

Calculating doubling time of focal lesions or massess can give a hint, whether it has a malignant or rather benign growth dynamics. Doubling time of malignant lesions is between 30 and 500 days with a median of 100 days.

Alberta Stroke Programme Early CT Score (ASPECTS)

ASPECTS is a quantitative topographic prognostic score based on unenhanced CT scan in patients with middle cerebral artery infarction. For each from 10 segments, one point is deducted from initial 10 points for each segment with detectable ischemic changes. A score ≤7 points predicts worse functional outcome at 3 months and an increased risk of symptomatic intracranial hemorrhage.



Capsula interna

Syndicate content