Winzer et al used the ratio of the adrenal gland to spleen in contrast-enhanced images of the abdomen. This can help to identify a patient at increased risk of mortality within 72-hours of the imaging study. The authors are from University Hospital Carl Gustav Carus in Dresden and affiliated hospitals.
Patient selection: intensive care unit
Outcome: mortality within 72-hours
Measurement: HU units of contrast-enhanced portal venous CT images using 3 mm slices
Adrenal gland measurements:
(1) Regions of interest in center of each adrenal gland.
(2) Areas of fat are avoided.
Splenic measurements:
(1) Place 3 circular regions of interest with area 2.0 square cm on 3 different axial planes through the cranial, middle and caudal third of the spleen.
(2) Measure HU during portal venous phase.
(3) Infarcts (hypodense triangular regions at periphery) are avoided.
ratio =
= (average HU for adrenal gland) / (average HU for spleen)
Interpretation:
• A ratio > 1.37 identifies a patient at increased risk for mortality.
Performance:
• The area under the ROC curve is 0.97.
• The accuracy depends on carefully selecting the areas for HU measurement.
