The hollow adrenal gland sign: a newly described enhancing pattern of the adrenal gland on dual-phase contrast-enhanced CT for predicting the prognosis of patients with septic shock

Short-term mortality prediction using a combination of clinical and CT features: Refining the prognosis of critically ill patients in shock

PURPOSE

To assess the predictive value of combining CT and clinical findings for predicting 10-day mortality in critically ill patients in shock.

MATERIALS AND METHODS

From January 1, 2018, to December 31, 2021, 289 consecutives critically ill patients in shock who underwent a contrast enhanced CT were included. Variables at the time of the CT were retrospectively extracted from medical charts. CT examinations were blindly analyzed by two independent radiologists. Multivariable analysis was performed, combining clinical and CT features. A simple survival score for 10-day mortality prediction was built and validated in a further independent external cohort of 70 patients.

RESULTS

10-day mortality rate was 135/289 (47%) in the study sample. At multivariate analysis, catecholamine infusion (OR = 2.11; 95%CI [1.21-4.18], P = 0.011), lactates level > 5 mmol/l (OR = 3.54; 95%CI [1.94-6.54], P < 0.001); total bilirubin > 50 mg/l (OR = 1.79 CI 95% [1.03-3.13], P = 0.039); small bowel dilation (OR = 1.82; 95%CI [1.01-3.32], P = 0.047); diffuse kidney infarction (OR = 2.76; 95%CI [1.26-6.37], P = 0.013) and superior mesentery artery < 5 mm (OR = 1.96; 95%CI [1.10-3.49], P = 0.021) were associated with 10-days mortality. The AUC of the combined model was 0.79; 95%CI [0.74-0.85] in the study sample and 0.87; 95%CI [0.71-0.91] in the validation cohort.

CONCLUSION

The combination of CT imaging features and clinical data should emerge as a novel approach to predict short-term mortality in critically ill patients in shock.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

Renal venous density in the arterial phase of contrast-enhanced CT predicts prognosis in septic shock

OBJECTIVE

To evaluate a series of vascular parameters derived from abdominal dual-phase contrast-enhanced CT as predictors of 14-day mortality and AKI within 7 days in septic shock.

METHODS

144 patients with septic shock and 60 negative cases were included. The vascular parameters from CT were measured and calculated, including aortic density in arterial (Dena-A) and venous phase (Dena-V), renal vein density in arterial (Denrv-A) and venous phase (Denrv-V), and renal vein-to-aortic density ratio in arterial (DenRrv/a-A) and venous phase (DenRrv/a-V). The parameters were compared between patients and controls, and between patients with different clinical outcomes, and assessed for predictive value of 14-day mortality and AKI within 7 days.

RESULTS

Patients with septic shock presented significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.002) levels than the controls. In the septic shock group, patients who died had significantly lower Denrv-A (p = 0.001) and lower DenRrv/a-A (p < 0.001) than those who survived. Patients who developed AKI had significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.011) than those who did not. Multivariate analysis suggested DenRrv/a-A as an independent predictor of 14-day mortality (OR 0.012; 95% confidence interval [CI]:0.002,0.086; p < 0.001) and Denrv-A as an independent predictor of AKI (OR 0.989;95% CI:0.982,0.997; p = 0.006).

CONCLUSION

In septic shock, significant decreases in Denrv-A and DenRrv/a-A were associated with the onset of AKI and predicted higher 14-day mortality.

ADVANCES IN KNOWLEDGE

The renal vein density and renal vein-aortic density ratio in arterial phase of dual-phase contrast-enhanced CT may serve as good predictors of AKI and mortality in septic shock.

CT signs of hypovolemic shock complex in patients with non-traumatic shock

PURPOSE

To assess the frequency of hypovolemic shock complex (HSC) signs on CT in patients who presented to the emergency department (ED) with undifferentiated non-traumatic shock. Secondary aim was to assess the correlation between HSC signs and all-cause mortality.

METHODS

This retrospective, single-center study included 100 patients who underwent contrast-enhanced thoraco-abdominal CT in the ED to evaluate the etiology for non-traumatic undifferentiated shock. All patients were retrospectively assigned a shock subtype (i.e., distributive, cardiogenic, hypovolemic, obstructive, multifactorial, and unknown) based on medical records. Patients' demographics and time to all-cause mortality up to 90 days were collected. All CT studies were re-assessed for the presence of HSC signs. Correlation between HSC signs, mortality and shock subtype was assessed.

RESULTS

Overall, 58% (58/100) of all patients had at least one HSC sign. Flattened inferior vena cava and adrenal hyper-enhancement were the most common HSC signs (27.3%, 27/99; in both). Overall mortality was 59% (59/100). When evaluated separately, shock liver was the only HSC sign to significantly correlate with increased mortality (84.6% vs. 55.2%, p = .04). However, patients with at least two HSC signs had a significantly higher mortality rate compared to patients without any HSC signs (73.5% vs. 45.2%, p = .017).

CONCLUSION

Most patients with non-traumatic shock had at least one HSC sign. Mortality rates were significantly higher in patients with two or more HSC signs compared to patients without any signs. Patients with shock liver sign had significantly higher mortality rates.

Adrenal heterogeneity in the arterial phase of contrast-enhanced CT predicts prognosis in septic shock: comparison with hollow adrenal gland sign

PURPOSE

To evaluate the prognostic value of adrenal heterogeneity in the arterial phase in patients with septic shock, comparatively to the hollow adrenal gland sign (HAGS).

METHODS

Totally 84 consecutive patients with septic shock (group S) were assessed retrospectively, and abdominal dual-phase contrast-enhanced CT was performed after the diagnosis of septic shock within one week. The patients were divided into two groups according to clinical outcome, including the survivor (group A, 41 cases) and death (group B, 43 cases) groups. Fifty negative cases were matched as the control (group C). The incidence of the HAGS in patients with septic shock (group S) was statistically analyzed. The average values of left adrenal density (Den-A and Den-V) and their standard deviations (SD_Den-A and SD_Den-V) in dual phases were measured. The above parameters were compared between groups A and B as well as with group C. The parameters were assessed for their predictive values of mortality in septic shock, comparatively to the HAGS.

RESULTS

Compared with group C, group S presented significantly higher Den-A (P = 0.003) and SD_Den-A (P < 0.001). There were significantly higher SD_Den-A (P < 0.001) in group B compared with group A. The incidence of the HAGS was about 27.4% (23/84) in group S. The sensitivity and specificity in predicting poor prognosis in patients with septic shock were 78% and 85% with SD_Den-A, at a cut-off value of 28.64, respectively. The sensitivity and specificity were 41% and 88% for the HAGS, respectively. The area under ROC curve (AUC) was significantly greater for SD_Den-A compared with the HAGS (0.820 vs. 0.670, P < 0.001).

CONCLUSION

Adrenal heterogeneity in the arterial phase can predict prognosis in patients with septic shock; the larger the SD_Den-A, the poorer the prognosis. The predictive efficiency of adrenal heterogeneity in the arterial phase is better than the HAGS.

Abdominal atherosclerosis is not a risk factor of nonocclusive mesenteric ischemia among critically ill patients: a propensity matching study

BACKGROUND

Although risk factors of occlusive acute mesenteric ischemia are well known, triggering factors of nonocclusive mesenteric ischemia (NOMI) remain unclear. Alongside to the known risk factors for NOMI, the role of atherosclerosis is not fully elucidated. The purpose of our study was to evaluate whether abdominal atherosclerosis is a risk factor for NOMI.

METHODS

From January 2018 to December 2021, all consecutive patients admitted to the intensive care unit who underwent contrast-enhanced CT for suspicion of NOMI were evaluated for inclusion. Clinical and biological data at the time of the CT scan were retrospectively extracted from medical charts and reviewed by a single radiologist. The cohorts were matched by a 1:1 propensity score based on the patient clinical, biological data, and abdominal CT features associated with NOMI. Noncontrast CT acquisitions were used to calculate calcium scores of the abdominal aorta, celiac trunk, superior mesenteric artery (SMA), and common iliac artery according to the Agatston method. Analyses were performed before and after propensity score matching.

RESULTS

Among the 165 critically ill patients included, 59 (36%) had NOMI. Before matching analysis, the SMA and total abdominal Agatston calcium scores were not different between patients without and with NOMI (52.00 [IQR = 0, 473] vs. 137.00 [IQR = 0, 259], P = 0.857, respectively, and 7253 [IQR = 1220, 21738] versus 5802 [IQR = 2075, 15,084]; P = 0.723). The results were similar after matching 38 patients with NOMI and 38 without: 153 [IQR = 0, 665] versus 85 [IQR = 0, 240] (P = 0.312) for the SMA calcium score, and 7915 [IQR = 1812, 21561] versus 4139 [IQR = 1440, 9858] (P = 0.170) for the total abdominal Agatston calcium score.

CONCLUSION

Our results suggest that atherosclerosis is not a risk factor for NOMI in critically ill patients.

Iodine uptake of adrenal glands: A novel and reliable spectral dual-layer computed tomographic-derived biomarker for acute septic shock

OBJECTIVES

Septic shock is a potentially fatal condition. This study aims to assess whether iodine uptake and iodine density of abdominal organs on dual-layer spectral detector computed tomography (SDCT) could serve as a new imaging biomarker for patients in septic shock.

METHODS

Here, 95 patients who received contrast-enhanced abdominal CT examinations were included and separated into two groups: group A - septic shock; group B - no shock condition. Preselected abdominal (right and left adrenal gland, right and left kidney, infrarenal inferior vena cava (IVC), pancreas, spleen, and liver) localizations were independently evaluated by two radiologists, who measured iodine concentrations (mg/ml) and Hounsfield units (HU).

RESULTS

In all, 1520 measurements of iodine concentrations in mg/ml and HU were performed, with 27 patients in group A and 68 in group B. Iodine concentrations in mg/ml and HU correlated significantly in all organs measured. The corresponding correlation coefficient (r) ranged from 0.809 (pancreas) to 0.963 (right kidney). Inter-rater reliability (IRR) was very good for mg/ml (κ = 0.8; p < 0.01) and good for HU (κ = 0.773; p < 0.01) measurements. The mean iodine concentration and HU of the adrenal glands in septic and nonseptic patients was 4.88 ± 1.16 mg/ml/153 ± 36 HU and 2.67 ± 1.07 mg/ml/112 ± 41 HU, respectively. Iodine concentrations in the adrenal glands were significantly higher in group A than in group B patients (p < 0.01). The other organs remained unaffected and no significant difference was observed between patients in group A and B. Patients in group A presented significantly more often with an iodine uptake of >3.5 mg/ml of one adrenal gland (sensitivity = 0.926, specificity = 0.849, AUC = 0.951) or/and a combined concentration of >7 mg/ml of both adrenal glands (sensitivity = 0.889, specificity = 0.836, AUC = 0.928).

CONCLUSION

SDCT-derived iodine concentration of the adrenal glands could serve as a novel imaging biomarker for patients in acute septic shock. Our data suggest that an iodine uptake of >3.5 mg/ml of at least one adrenal gland or a combined iodine uptake of >7 mg/ml in both adrenal glands identifies patients in this condition.

The Hollow Adrenal Gland Sign: An Ominous Alert

Teaching Point: The hollow adrenal gland sign is common, and may be specific, in patients with septic shock, and is a predictor of poor prognosis.

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

Background In critically ill ICU patients, initial results showed that opposite enhancement of the adrenal glands (↑) and spleen (↓) on portal venous CT scans was associated with increased mortality over the next days to a month, with short-term mortality being best predicted. The study aimed to validate the adrenal-to-spleen ratio determined in a pilot study concerning mortality prediction.

Method 371 portal venous CT scans of 203 ICU patients (127 men, age: 68.1 ± 14.4 years) were included in the retrospective analysis. Region-of-interest (ROI)-based Hounsfield units of the adrenal glands and the spleen and their density ratio were evaluated. The Matthews correlation coefficient (MCC) and ROC analysis were used to establish a threshold for the adrenal-to-spleen ratio regarding mortality within 72 hours of imaging. The quality of the classification of survivors and deceased patients in the current collective based on the threshold determined in a pilot study and on the current threshold was determined. The precision-recall curve (PRC) was used to test the influence of the addition of patients with low vital risk on the ROC.

Results The current threshold of 1.37 for the adrenal-to-spleen ratio provides good discriminatory power between those who died and those who survived (MCC: 0.87; sensitivity: 83.7 %; specificity: 99.1 %; PPV: 93.2 %; NPV: 97.6 %) and differs only slightly from the threshold of 1.41 determined in the pilot study, which consequently has comparable discriminatory power.

Conclusion As a reproducible image-based prognostic marker, the portal venous adrenal-to-spleen ratio has a high predictive power for short-term death in ICU patients. It is, therefore, suitable as an indicator of high risk of death within 72 hours after imaging.

Key Points: 

Citation Format

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

Simple Summary

Non-invasive characterization of adrenal lesions requires a rigorous approach. Although CT is the cornerstone of adrenal lesion characterization, a multimodality multiparametric imaging approach helps improve confidence in adrenal lesion characterization.

Abstract

Detection and characterization of adrenal lesions have evolved during the past two decades. Although the role of imaging in adrenal lesions associated with hormonal secretion is usually straightforward, characterization of non-functioning adrenal lesions may be challenging to confidently identify those that need to be resected. Although many adrenal lesions can be readily diagnosed when they display typical imaging features, the diagnosis may be challenging for atypical lesions. Computed tomography (CT) remains the cornerstone of adrenal imaging, but other morphological or functional modalities can be used in combination to reach a diagnosis and avoid useless biopsy or surgery. Early- and delayed-phase contrast-enhanced CT images are essential for diagnosing lipid-poor adenoma. Ongoing studies are evaluating the capabilities of dual-energy CT to provide valid virtual non-contrast attenuation and iodine density measurements from contrast-enhanced examinations. Adrenal lesions with attenuation values between 10 and 30 Hounsfield units (HU) on unenhanced CT can be characterized by MRI when iodinated contrast material injection cannot be performed. ¹⁸F-FDG PET/CT helps differentiate between atypical benign and malignant adrenal lesions, with the adrenal-to-liver maximum standardized uptake value ratio being the most discriminative variable. Recent studies evaluating the capabilities of radiomics and artificial intelligence have shown encouraging results.

Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex". A pictorial essay

Septic shock is a medical emergency that represents one of the most important underlying causes for presentation to the Emergency Department. Sepsis is defined as organ dysfunction, life-threatening event caused by a deregulated inflammatory host response to infection, with a mortality risk ranging from 10 to 40%. Early sepsis identification is the cornerstone of management and diagnostic imaging can play a pivotal role in this clinical context. The choice of imaging modality depends on several factors, associated with the clinical condition and the presence or absence of localising signs and symptoms. The diagnostic accuracy of contrast-enhanced total-body CT has been well established during septic shock, allowing for a rapid, panoramic, and detailed study of multiple body areas, simultaneously. The aim of this article is to illustrate the controversial CT hypoperfusion complex in patients with septic shock, characterised by the following imaging features: decreased enhancement of the viscera; increased mucosal enhancement; luminal dilation of the small bowel; mural thickening and fluid-filled loops of the small bowel; the halo sign and flattening of the inferior vena cava; reduced aortic diameter; peripancreatic oedema; abnormal parenchymal perfusion; and other controversial findings that are variably associated with each other and reversible during the early stages. Increasing physicians' awareness of the significance of these findings could prompt alternative approaches to the early assessment and management of septic shock. In this perspective, CT imaging represents a useful tool for a complete, rapid and detailed diagnosis of clinically suspected septic shock, which can be used to improve patient outcomes.

Hollow adrenal gland sign on dual-phase contrast-enhanced CT in critically ill patients with sepsis

OBJECTIVE

We aimed to describe the clinical manifestations of patients with sepsis who had the hollow adrenal gland sign (HAGS) during the acute phase of resuscitation and evaluated its value in predicting in-hospital mortality.

METHODS

We performed a single-center, retrospective study of patients with sepsis who visited the emergency department (ED) from November 2015 to December 2018. The patients were categorized into the positive HAGS (pHAGS) and negative HAGS (nHAGS) groups, based on its presence in initial dual-phase contrast-enhanced abdominal computed tomography (CT). The primary outcome was in-hospital mortality. A multiple logistic regression model was developed to assess variables related to in-hospital mortality.

RESULTS

In all, 156 patients were included, and 36.5% (n = 57) was assigned to the pHAGS group. Both the maximal Sequential Organ Failure Assessment score within 24 h after ED arrival (10, interquartile range [IQR] 7-13 vs. 8, IQR 6-10, p < 0.01) and APACHE II score (24, IQR 20-31 vs. 20, IQR 17-25, p < 0.01) were significantly higher in the pHAGS than in the nHAGS group; the former group received significantly more interventions including vasopressors, renal replacement therapy, mechanical ventilation, and transfusions; in-hospital mortality was significantly higher in the former than in the latter group (29.8% vs. 10.1%, p < 0.01). pHAGS was an independent predictor of in-hospital mortality (adjusted odds ratio, 2.89; 95% confidence interval, 1.08-7.78; p = 0.04).

CONCLUSIONS

Patients with sepsis who showed the HAGS had more severe illness than those who did not, and had an increased need for organ-supportive interventions. Presence of the HAGS was independently associated with in-hospital mortality.

Mapping a mammalian adult adrenal gland hierarchy across species by microwell-seq

Recently, single-cell RNA-seq technologies have been rapidly updated, leading to a revolution in biology. We previously developed Microwell-seq, a cost-effective and high-throughput single cell RNA sequencing(scRNA-seq) method with a very simple device. Most cDNA libraries are sequenced using an expensive Illumina platform. Here, we present the first report showing combined Microwell-seq and BGI MGISEQ2000, a less expensive sequencing platform, to profile the whole transcriptome of 11,883 individual mouse adult adrenal gland cells and identify 18 transcriptionally distinct clusters. Moreover, we performed a single-cell comparative analysis of human and mouse adult adrenal glands to reveal the conserved genetic networks in these mammalian systems. These results provide new insights into the sophisticated adrenal gland hierarchy and provide a benchmark, low-cost strategy for high-throughput single-cell RNA study.