Bilateral adrenal enhancement revised—adrenal-to-spleen ratio as an appropriate mortality predictor

Abstract

Purpose To investigate whether adrenal gland radiodensities alone or set in relation to either the inferior vena cava (IVC) or the spleen can predict hospital mortality in intensive care unit patients. Methods One hundred thirty-three intensive care patients (90 males, age: 66.3 ± 14.5 years) with an acute clinical deterioration were included in this retrospective analysis. CT attenuation (Hounsfield units) of adrenal glands, IVC, and spleen was evaluated by 2 radiologists separately. Adrenal-to-IVC and adrenal-to-spleen ratios were calculated. Receiver operating characteristic (ROC) analysis, combined with the Matthews correlation coefficient (MCC) as a classifier, was used to assess which parameter is the most suitable for short-term, intermediate-term, and overall mortality prediction. Interrater agreement was assessed using intraclass correlation coefficient (ICC). Results The highest discriminative power to distinguish between deceased and survivors was found for the adrenal gland-to-spleen ratio for the 72-h mortality. A threshold of > 1.4 predicted 72-h mortality with a sensitivity of 79.31% and a specificity of 98.08% (area und the curve (AUC) = 0.94; p < 0.0001; MCCs = 0.81). The positive likelihood ratio was 41; the positive predictive value was 92.20%. Adrenal gland-to-spleen ratio was also best suited to predict the 24-h and overall mortality. ICCs of HU measurements in adrenal gland, IVC, and spleen indicated a high interrater agreement (ICC 0.95–0.99). Conclusions To conclude, the adrenal-to-spleen ratio in CT in portal venous phase may serve as an imaged-based predictor for short, intermediate, and overall mortality and as reproducible prognostic marker for patient outcome.

The Portal-Venous Enhancement Ratio of the Adrenal Glands and Spleen as a Short-Term Predictor of Mortality in Intensive Care Patients

“…We tried to limit this by averaging spleen measurements and excluding triangular, wedge-shaped, and inhomogeneous regions. The measurements in this study were performed by a single radiologist since the intraclass correlation coefficient of previous studies (0.90) [15,16] showed very high agreement among evaluators. The adrenal-to-spleen ratio takes into consideration the opposite enhancement patterns with decreasing density of the spleen and increasing density of the adrenal glands.…”

“…Im klinisch-radiologischen Alltag fielen uns bei einer Vielzahl dieser Patienten hyperdense Nebennieren in der kontrastmittelgestützten CT auf, wobei einige Patienten in den Folgetagen verstarben. Die unterschiedlichen Ansätze vorangegangener Studien bezüglich der Auswahl der Kontrastmittelphasen und der Organe bewogen uns zunächst zu einem systematischen Vergleich des Anreicherungsver-haltens in der arteriellen und portalvenösen Phase auf Grundlage ROI-basierter Messungen [15,16]. Wir fokussierten uns auf die Nebennieren und die Milz sowie die großen Abdominalgefäße.…”

“…In dieser Phase besitzen schon die Organdichten für sich einen substanziellen Vorhersagewert, innerhalb der ersten 3 Tage nach Bildgebung zu versterben [15]. Die Güte der Vorhersage wird jedoch entscheidend gesteigert, wenn die Organdichtewerte entweder in Relation zueinander oder zu den großen Abdominalgefäßen gesetzt werden [16].…”

Adrenal Mass Characterization in the Era of Quantitative Imaging: State of the Art

“…In the specific situation of circulatory shock, the adrenal glands appear to be hyperenhanced, defined as bilateral adrenal attenuation values greater than those of the inferior vena cava [15]. When quantifying this enhancement, an adrenal-to-spleen ratio of >1.41 in portal venous phase CT images is associated with a likelihood ratio of 41 for lethal outcomes [15].…”

“…In the specific situation of circulatory shock, the adrenal glands appear to be hyperenhanced, defined as bilateral adrenal attenuation values greater than those of the inferior vena cava [15]. When quantifying this enhancement, an adrenal-to-spleen ratio of >1.41 in portal venous phase CT images is associated with a likelihood ratio of 41 for lethal outcomes [15]. The "hollow adrenal gland sign", defined as peripheral enhancement during the arterial phase and whole-gland enhancement during the portal phase, is considered to be a specific pattern of septic circulatory shock compared with hemorrhagic shock [8].…”