Purpose: The study sought to assess the frequency and prognostic value of hyperattenuating adrenal glands on contrast-enhanced computed tomography (CT) scans of surgical intensive care unit (ICU) patients with acute clinical deterioration.Methods: Eighty-eight consecutive ICU patients (63.2 14.5 years of age) were included in this retrospective analysis. All patients underwent biphasic contrast-enhanced CT due to an acute clinical deterioration. Hyperattenuation of the adrenal glands was assessed subjectively and objectively. Subjective presence or absence of hyperattenuating adrenal glands was assessed by 2 blinded radiologists (J.B. and R.S.L.) in consensus. Hounsfield units (HU) were measured in the adrenal glands and in the inferior vena cava. Objective hyperattenuation was defined as HU (adrenal glands) > HU (inferior vena cava) with a 15-HU threshold. Death within 14 days following CT was set as endpoint and acquired from electronic patient data.Results: Thirty-eight patients (43.2%, Group Asobj) exhibited hyperattenuation of the adrenal glands, whereas 50 patients (56.8%, Group Bsobj) did not. Concerning the objective analysis, 31 patients (35.2%, Group Aobj) exhibited hyperdense adrenal glands, whereas 53 patients (64.8%, Group Bob.) did not. Overall 27 of 88 patients (30.6%) died within 14 days following the CT examination. Lethal outcome was significantly more frequent among patients in Group Asobj and Aobj (19 of 38 patients [50.0%] and 15 of 31 patients [48.4%]) as compared with patients in Group Bsobj (8 of 50 patients [16.0%]) and Group Bobj (12 of 57 patients [21.1%]; P <.05). Subjective and objective analysis correlated significantly (P <.05).Conclusions: Hyperattenuation of adrenal glands on contrast-enhanced CT of ICU patients with acute clinical deterioration is associated with a high mortality and might serve as a prognostic marker for patients' outcome.

Objective The purpose of this study was to assess the influence of liver cirrhosis and portal hypertension on diffusion coefficients of the spleen. Material and Methods We retrospectively evaluated 50 patients with liver cirrhosis and 50 patients without any history of liver disease who underwent magnetic resonance imaging of the upper abdomen, including echo planar diffusion-weighted imaging using b values of 50, 300 and 600mm2/s. Spleen apparent diffusion coefficient (ADC), liver ADC, muscle ADC and normalized spleen ADC (defined as the ratio of spleen ADC to muscle ADC) were compared between cirrhotic patients and patients in the control group and correlated with Child–Pugh stages. Reproducibility was assessed by measuring interclass correlation coefficient (n=11). Additionally, in eight patients, ADC measurements were performed 1 day before and 3 days after transjugular intrahepatic portosystemic shunt (TIPSS) implantation. Results Compared with control subjects, patients with cirrhosis and portal hypertension had significantly higher spleen ADCs (P=.0001). There was a statistically significant correlation between Child–Pugh grade and spleen ADC (Pearson correlation coefficient, observer 1 r=0.6, P=.0001; observer 2 r=0.5, P=.0001). After TIPSS implantation, we observed a reduction in spleen ADC values. Spleen ADC measurements showed a high reproducibility (interclass correlation coefficient 0.75, P=.001). Conclusion Our data suggest that different stages of liver cirrhosis and portal hypertension correlate with ADC values of the spleen. Furthermore, ADC values of the spleen decrease after TIPSS implantation. Further studies are required to understand the potential clinical values of these observations.

Background: Biexponential analysis has been used increasingly to obtain contributions of both diffusion and microperfusion to the signal decay in diffusion-weighted imaging DWI of different parts of the body.Purpose: To compare biexponential diffusion parameters of transplanted kidneys obtained with three different calculation methods.Material and Methods: DWI was acquired in 15 renal allograft recipients (eight men, seven women; mean age, 52.4 +/- 14.3 years) using a paracoronal EPI sequence with 16 b-values (b = 0-750 s/mm(2)) and six averages at 1.5T. No respiratory gating was used. Three different calculation methods were used for the calculation of biexponential diffusion parameters: F-p, ADC(P), and ADC(D) were calculated without fixing any parameter a priori (calculation method 1); ADC(P) was fixed to 12.0 mu m(2)/ms, whereas F-p and ADC(D) were calculated using the biexponential model (calculation method 2); multistep approach with monoexponential fitting of the high b-value portion (b >= 250 s/mm(2)) for determination of ADC(D) and assessment of the low b intercept for determination of F-p (calculation method 3). For quantitative analysis, ROI measurements were performed on the according parameter maps.Results: Mean ADC(D) values of the renal cortex using calculation method 1 were significantly lower than using calculation methods 2 and 3 (P < 0.001). There was a significant correlation between calculation methods 1 and 2 (r = 0.69 (P < 0.005) and calculation methods 1 and 3 (r = 0.59; P < 0.05) as well as calculation methods 2 and 3 (r = 0.98; P < 0.001). Mean F-p values of the renal cortex were higher with calculation method 1 than with calculation methods 2 and 3 (P < 0.001). For F-p, only the correlation between calculation methods 2 and 3 was significant (r = 0.98; P < 0.001).Conclusion: Biexponential diffusion parameters differ significantly depending on the calculation methods used for their calculation.

Purpose: To evaluate the feasibility of diffusion-tensor (DT) imaging at 3 T for functional assessment of transplanted kidneys.Materials and Methods: This study was approved by the local ethics committee; written informed consent was obtained. Between August 2009 and October 2010, 40 renal transplant recipients were prospectively included in this study and examined with a clinical 3-T magnetic resonance (MR) imager. An echo-planar DT imaging sequence was performed in coronal orientation by using five b values (0, 200, 400, 600, 800 sec/mm(2)) and 20 diffusion directions. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were determined for the cortex and medulla of the transplanted kidney. Relationships between FA, ADC, and allograft function, determined by the estimated glomerular filtration rate (eGFR), were assessed by using Pearson correlation coefficient. ADC and FA were compared between patients with good or moderate allograft function (group A; eGFR > 30 mL/min/1.73 m(2)) and patients with impaired function (group B; eGFR. 30 mL/min/1.73 m2) by using a student t test. P < .05 indicated a statistically significant difference.Results: Mean FA of the renal medulla and cortex was significantly higher in group A (0.39 +/- 0.06 and 0.17 +/- 0.4) compared with group B (0.27 +/- 0.05 and 0.14 +/- 0.03) (P < .001 and P = .009, respectively). Mean ADCs of renal cortex and medulla were significantly higher in group A than in group B (P = .007 and P = .01, respectively). In group B, mean medullary FA was significantly lower in patients whose renal function did not recover (0.22 +/- 0.02) compared with those with stable allograft function at 6 months (0.29 +/- 0.05, P < .001). There was significant correlation between eGFR and medullary FA (r = 0.65, P,.001), cortical ADC (r = 0.43, P = .003), and medullary ADC (r = 0.35, P = .01).Conclusion: DT imaging is a promising noninvasive technique for functional assessment of renal allografts. FA values in the renal medulla exhibit a good correlation with renal function. (R) RSNA, 2012