Description: It is difficult to make a correct diagnosis when a lesion arising from adrenohepatic fusion occurs. Also, the anatomical characteristics may lead to various radiological features so that it is frequent to under- or over-treat a lesion from adrenohepatic fusion. Adrenohepatic fusion is characterized by the close intermixture of hepatocytes and adrenocortical cells with rare or no formation of a peri-adrenal capsule. The purpose of this clinical perspective was to describe the direct and indirect imaging features of adrenohepatic fusion and show their clinical implications for patient care.

Description: Purpose The aim of this study was to determine the correlation between the liver and spleen apparent diffusion coefficient (ADC) values of patients with chronic liver disease and the presence and the degree of ascites. Materials and method In this retrospective study, we assessed 107 patients with chronic liver disease and 39 control subjects who underwent upper abdominal MR imaging including echo-planar diffusion-weighted imaging (DWI). Among the 107 cirrhotic patients, 56 were classified as group 1, 25 as group 2, and 26 as group 3 according to the absence, the presence of minimal, and the presence of massive ascites, respectively. The scores of model for end-stage liver disease (MELD) were matched between groups as the standard reference. The liver ADC, spleen ADC, and normalized liver ADC values were compared between the control group and patients’ groups. Results Patients with massive ascites had significantly higher MELD score compared with the other groups. The MELD score was also significantly higher in patient groups than in control group. The liver and normalized liver ADCs of patients’ groups were significantly lower than that of the control group. With some overlap among groups, the measured ADC values decreased as the amount of the ascites increased, and these relationships were statistically significant. Furthermore, compared to control group, patients with massive ascites had significantly higher spleen ADCs. Conclusion Our results indicate that the ADC value of the liver and spleen correlates with the presence and the degree of ascites in patients with chronic liver disease, and merits further study.

Description: Introduction Adrenal hemorrhage is an uncommon but potentially life-threatening condition, particularly in cases of bilateral adrenal hemorrhage causing primary adrenal insufficiency. It is difficult to diagnose clinically, particularly in critically ill patients, given its non-specific symptoms and signs, which include abdominal pain, vomiting, fever, weakness, hypotension, and altered conscious state. Non-traumatic adrenal hemorrhage has been observed to occur in times of physiological stress, such as post-surgery, sepsis, burns, and hypotension. This is hypothesized to be due to a combination of increased arterial blood flow to the adrenal glands, the paucity of draining adrenal venules and adrenal vein thrombosis, leading to intra-glandular vascular congestion and subsequent hemorrhage. Case series We present four cases of non-traumatic adrenal hemorrhage, which demonstrated features of preceding adrenal congestion (adrenal gland thickening and peri-adrenal fat stranding) on computed tomography (CT) imaging. Comparison was made with 12 randomly selected intensive care patients to observe if these findings were prevalent in this subgroup of patients. Conclusion Non-traumatic adrenal hemorrhage is an uncommon condition that is difficult to diagnose clinically. As such, it may be useful to recognize CT features of adrenal congestion as a sign for potential adrenal dysfunction and subsequent adrenal hemorrhage, so early steroid replacement therapy can be commenced to prevent death from adrenal insufficiency.

Description: Purpose The purpose of the study is to investigate the computed tomographic characteristic and clinical findings of gastric neuroendocrine carcinoma (G-NEC) to increase awareness of this disease. Methods Twenty-two patients with a diagnosis of G-NEC were identified through the PACS of our hospital from August 2010 to November 2014. The clinical data, computed tomography (CT) features, and pathology records were analyzed. Results Among the 22 patients, 21 were male (95.45%), and 1 was female (4.55%). The mean age was 63.5 years old. Positive rates of neuroendocrine markers were 77.28% for chromogranin A staining, 86.36% for synaptophysin staining. All cases were single lesions including 16 (72.73%) in the gastric fundus, 3 (13.64%) in the gastric body and 1 (4.55%) in the gastric angle. Additionally 2 (9.09%) were found in the gastric antrum. Gastric wall was local thickening in 15 cases, and mass formation in 7 cases, with the stenosis and deformation of the adjacent gastric cavity. The long-axis diameter of the lesions ranged from 1.2 to7.4 cm (mean diameter, 2.47 cm), and the long-axis diameter was 〈2 cm in 12 case, 2–7.4 cm in 10 cases. The radiodensity values of the lesions were homogeneous density in 15 cases ranging from 22 to 47 HU (mean 34 HU). An ulcer with an irregular base and slightly raised borders located in the stomach was seen in 19 cases. The CT images showed homogeneous enhancement in 15 cases and heterogeneous enhancement in 7 cases. Obvious enhancement was seen in two cases, moderate enhancement was seen in sixteen cases, and mildly enhancement was seen in four cases. The peak value occurred in the arterial phase in 5 cases and the peak value was seen in 17 cases in the portal phase. Eleven lesions invaded the gastric serosa, and lymphatic metastasis was observed in 21 cases, 8 of which were combined with liver metastasis. CT images revealed 2 cases of the liver metastasis had obvious enhancement. Conclusion The CT features regarding location, incidence rates of ulcer and enhancement pattern described in our findings are common in all malignant gastric tumors. Therefore, the diagnosis of G-NEC must be confirmed with pathological test.

Description: Purpose The prognostic value of 18 F-deoxyglucose positron emission tomography ( 18 F-FDG PET) on hepatocellular carcinoma (HCC) remains inconclusive. This study aims to investigate the prognostic role of pretreatment 18 F-FDG PET on HCC patients by meta-analysis. Methods PubMed, Embase, Cochrane library, and Wanfang databases were searched until June 2015. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were synthesized by Stata 10.0, and the combined results were used as effective values. Results Twenty-two studies containing a total of 1721 patients were identified. According to random-effect model, meta-analysis results showed that high Tumor SUV/Liver SUV (Tsuv/Lsuv) ratio was significantly associated with poorer overall survival (OS) (HR = 2.04; 95% CI 1.50–2.79; P  = 0.000) and poorer disease-free survival (HR = 7.17; 95% CI 3.58–14.36; P  = 0.000); and high Tumor SUV (Tsuv) value was also correlated with poor OS (HR = 1.53; 95% CI 1.26–1.87; P  = 0.000). Meanwhile, subgroup analysis results showed that the significant association above was not altered by study sample size, parameter cutoff value, analytic method, and follow-up period, but there was no significant association between Tsuv/Lsuv ratio and OS in patients who underwent resection (HR = 1.71; 95% CI 1.00–2.92; P  = 0.052). Conclusions Both high Tsuv/Lsuv ratio and high Tsuv value are associated with poor prognosis in HCC patients. Therefore, pretreatment 18 F-FDG PET is a useful tool in predicting the prognosis of HCC patients. More studies with explicit treatment modalities are required to investigate the prognostic value of pretreatment 18 F-FDG PET on HCC patients.

Description: The prevalence of obesity is increasing, along with the number of bariatric surgical procedures performed to treat obesity. Laparoscopic sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and laparoscopic gastric banding (GB) comprise the vast majority of procedures with SG now the dominant procedure in the USA. Although multidetector computed tomography (MDCT) is not always the examination of choice for a particular suspected complication, many of these patients present with non-specific abdominal symptoms and undergo MDCT evaluation as an initial diagnostic test. This pictorial essay will review and discuss the normal post-surgical bariatric appearance on MDCT, and the appearance of common and uncommon complications associated with the common bariatric procedures on MDCT with correlative imaging. SG complications include leak/abscess, hemorrhage, splenic injury, and portomesenteric thrombosis. RYGB complications include leak/abscess, gastrogastric fistula, small bowel obstruction, internal hernia, and intussusception. Although GB is waning in popularity, radiologists continue to see the legacy of these patients and complications include gastric prolapse, band erosion, and port/tubing mechanical failures. Awareness of the characteristic findings of bariatric complications on MDCT is critical, allowing for earlier recognition and prompt intervention.

Description: Purpose The purpose of the study was to assess the inter-observer agreement on the qualitative and quantitative evaluation of relative signal intensity of liver lesions on delayed hepatobiliary phase (HBP) MRI with gadoxetate (Gd-EOB-DTPA). Methods 105 patients with liver lesions, who had delayed HPB MRI using gadoxetate were reviewed retrospectively. For each patient, four readers (two fellows in training and two attending radiologists) qualitatively assessed the relative SI of the largest representative lesion on a five point scale, and quantitatively measured the relative SI of the lesion to adjacent liver parenchyma using region of interests (ROI). Intra-class correlation (ICC) and kappa statistics with quadratic weights ( k ) analysis, and maximally selected rank statistic were performed. Results Substantial agreement between fellows ( k  = 0.719; ICC = 0.705) and almost perfect agreement between attending radiologists ( k  = 0.853; ICC = 0.849) were found for both qualitative and quantitative assessments of relative SI on delayed HPB imaging. A cut-off ratio to differentiate between hypointense and iso- to hyperintense lesions by ROI was calculated to be 0.90. Conclusion Inter-observer agreement of liver lesion relative SI on delayed HBP imaging is high and may improve with radiologist experience. A cut-off ratio of relative SI at 0.90 may be useful to quantitatively distinguish hypointense from iso- to hyperintense liver lesions.

Description: Purpose To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial administration of iodixanol, compared to non-administration. Methods We retrospectively identified 650 patients who had intravenous iodixanol-enhanced CT, 695 with intra-arterial iodixanol cardiac catheterization, 651 with unenhanced CT, and those who also had baseline and follow-up serum creatinine within 5 days of the exam. From the medical records, we recorded the gender, age, baseline and follow-up serum creatinine/eGFR; underlying renal injury risk factors; indication for imaging; contrast material administration volume, concentration, and route of administration; and use of pre-imaging prophylactic measures for CIN. Univariate and multivariate models were used to determine predictors of CIN. Results Baseline eGFR was lower for patients undergoing unenhanced CT than intravenous or intra-arterial patients (68 vs. 74.6 and 72.2, respectively, p  〈 0.01) and not different between intravenous and intra-arterial patients ( p  = 0.735). Simple logistic regression did not show a difference in the rate of CIN in patients who received intravenous vs. intra-arterial iodixanol (28 of 650, 4%, vs. 28 of 695, 4%, respectively, p  = 0.798), nor a higher rate of CIN than seen with unenhanced CT (45 of 651, 7%, p  = 0.99 and p  = 0.98 by one-sided t test). Multivariate regression modeling showed that only elevated baseline creatinine or decreased eGFR and low hematocrit/hemoglobin were associated with CIN incidence (odds ratio 1.28 and 2.5; p  〈 0.023 and 〈0.006, respectively). Conclusions Elevation in serum creatinine due to intravenous and intra-arterial iodixanol administration is infrequent and is not more common than after unenhanced CT scans.

Description: Purpose To explore whole-lesion histogram analysis of the hepatobiliary phase (HBP) defect in indeterminate hypovascular liver lesions for predicting progression to arterial-enhancing hepatocellular carcinoma (HCC). Methods Twenty patients undergoing gadoxetic acid-enhanced MRI for HCC screening with 12° and 25° flip angle (FA) HBP acquisitions demonstrating an indeterminate lesion showing HBP hypointensity but no arterial enhancement were included. Volumes-of-interest were placed on HBP defects, from which histogram metrics were obtained. Associations between these metrics and progression to arterial-enhancing HCC on follow-up imaging were investigated. Lesions were also assessed for the presence of a signal abnormality on conventional sequences. Results 40% of lesions progressed to arterial-enhancing HCC; 60% were stable at ≥6 months follow-up. Neither T2-hyperintensity increased diffusion signal nor portal/equilibrium phase washout was different between progressing and nonprogressing lesions ( p  = 1.0). Among direct signal intensity-based measures (overall mean; mean of bottom 10th, 10–25th, and 25–50th percentiles), area-under-the-curve (AUC) for prediction of progression to arterial-enhancing HCC was consistently higher at 25° (range 0.619–0.657) than at 12° (range 0.512–0.548). However, at both FAs, the four measures with highest AUC were measures related to lesion texture and heterogeneity [standard deviation (SD), coefficient of variation (CV), skewness, and entropy], having AUC of 0.655–0.750 at 12° and 0.686–0.800 at 25. The metric with highest AUC at 12° was SD (AUC = 0.750) and at 25° was CV (AUC = 0.800). Conclusion Whole-lesion histogram HBP measures of indeterminate hypovascular liver lesions may help predict progression to arterial-enhancing HCC by reflecting greater lesion heterogeneity, particularly at higher FA. Larger studies are therefore warranted.