Csilla Balassy

Liver Fibrosis: Histopathologic and Biochemical Influences on Diagnostic Efficacy of Hepatobiliary Contrast-enhanced MR Imaging in Staging

PURPOSE To evaluate the diagnostic performance of gadoxetic acid-enhanced magnetic resonance (MR) imaging in the staging of liver fibrosis in patients with diffuse chronic liver diseases (CLDs) and to investigate the factors that may influence the results. MATERIALS AND METHODS With the approval of the Hospital Ethics Committee and waiver of the informed consent requirement, data in 102 patients with histologically proven liver fibrosis (classified according to the METAVIR system) of various underlying causes were retrospectively analyzed. Patients underwent 3.0-T MR imaging with gadoxetic acid. The signal intensity of the liver was defined by using region of interest measurements before contrast material injection and in the hepatobiliary phase (20 minutes after contrast material administration), and relative enhancement was calculated. Univariate and multivariate regression analyses were applied to identify variables associated with relative enhancement measurements, and the performance of relative enhancement measurements in the staging of liver fibrosis was assessed by using area under the receiver operating characteristic curve (AUC) analysis. RESULTS At analysis of the relationship between enhancement measurements and histologic parameters, the relative enhancement values correlated strongly with liver fibrosis stage (r = -0.65, P < .0001) and moderately with necroinflammatory activity grades (r = -0.41, P = .002) and the presence of iron load (r = -0.21, P = .05). In multivariate analysis, only liver fibrosis stage independently influenced relative enhancement values (P < .001). The measurements performed well in the staging of liver fibrosis, with an AUC of 0.81 for stages of F1 or greater, 0.82 for stages of F2 or greater, 0.85 for stages of F3 or greater, and 0.83 for stage F4. Increased aspartate aminotransferase, gammaglutamyl transpeptidase, and alkaline phosphatase levels were independent predictors of false-negative results. CONCLUSION The presence of hepatic fibrosis can be assessed with good discrimination by using gadoxetic acid-enhanced MR imaging, but assessment can be confounded in the setting of abnormal aspartate aminotransferase, gammaglutamyl transpeptidase, and alkaline phosphatase levels.

Noninvasive Differentiation of Simple Steatosis and Steatohepatitis by Using Gadoxetic Acid–enhanced MR Imaging in Patients with Nonalcoholic Fatty Liver Disease: A Proof-of-Concept Study

PURPOSE To determine whether gadoxetic acid-enhanced magnetic resonance (MR) imaging can be used to distinguish between simple steatosis and nonalcoholic steatohepatitis (NASH) in patients with nonalcoholic fatty liver disease (NAFLD), defined according to the steatosis activity and fibrosis (SAF) scoring system, which is based on the semiquantitative scoring of steatosis activity and liver fibrosis. MATERIALS AND METHODS The local institutional review committee approved this study and waived written informed consent. This was a retrospective study of gadoxetic acid-enhanced 3-T MR imaging performed in 81 patients with NAFLD (45 men [56%]; mean age, 56 years; range, 25-78 years). The MR images were analyzed by using the relative enhancement (the ratio of signal intensities of the liver parenchyma before and 20 minutes after intravenous administration of gadoxetic acid). Univariate and multiple regression analyses were applied to identify variables associated with relative enhancement measurements. The ability of relative enhancement to allow differentiation between simple steatosis and NASH was assessed by using area under the receiver operating characteristic (ROC) curve analysis. RESULTS Relative enhancement negatively correlated with the degree of lobular inflammation (r = -0.59, P < .0001), ballooning (r = -0.44, P < .0001), and fibrosis (r = -0.59, P ≤ .0001), but not with steatosis (r = -0.16, P = .15). Patients with NASH had a significantly lower relative liver enhancement (0.82 ± 0.22) than those with simple steatosis (1.39 ± 0.52) (P < .001). Relative enhancement measurements performed well in the differentiation between simple steatosis and NASH, with an area under the ROC curve of 0.85 (95% confidence interval: 0.75, 0.91) (cutoff = 1.24, sensitivity = 97%, specificity = 63%). CONCLUSION Gadoxetic acid relative enhancement was significantly lower in patients with NASH than in patients with simple steatosis, but further prospective studies are warranted.

Susceptibility-weighted MR Imaging in the Grading of Liver Fibrosis: A Feasibility Study

PURPOSE To assess the feasiblity of magnetic resonance (MR) susceptibility-weighted (SW) imaging as a tool to evaluate liver fibrosis grades in patients with chronic liver diseases (CLD) utilizing signal intensity (SI) measurements, with histopathologic findings as the reference standard. MATERIALS AND METHODS This retrospective study was approved by the local ethics committee. All subjects gave written informed consent. Eighty consecutive patients (mean age, 56.8 years), 60% of whom were male [n = 48] and 40% of whom were female [n = 32], with CLD due to various underlying causes and histopathologically proved liver fibrosis were included. Biopsies were evaluated for liver fibrosis and necroinflammatory activity (according to METAVIR scoring system), iron load, and steatosis. Two radiologists, blinded to the clinical data, assessed regions of interest in the liver and spinal muscle in consensus. Liver-to-muscle SI ratios were calculated and correlated to histopathologic findings and clinical data by using univariate and multivariate regression analysis. RESULTS Liver-to-muscle SI ratio decreased in parallel with the increasing grade of liver fibrosis and correlated strongly with liver fibrosis (r = -0.81, P < .0001) and moderately with necroinflammatory activity (r = -0.52, P < .0001) and iron load (r = -0.37, P = .0002) but did not correlate with steatosis (r = -0.18, P = .11). In multiple regression analysis, liver fibrosis and iron load independently influenced SW imaging measurements, explaining 69% of the variance of liver-to-muscle SI ratio (R(2) = 0.69, P < .001). Liver-to-muscle SI ratio performed well in grading liver fibrosis, with an area under the receiver operating characteristic curve of 0.92 for scores of F2 or higher and 0.93 for score of F4 (liver cirrhosis). CONCLUSION SW imaging is a feasible noninvasive tool to detect moderate and advanced liver fibrosis in CLD patients.

Direct detector radiography versus dual reading computed radiography : feasibility of dose reduction in chest radiography

The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality.

The skull unfolded: a cranial CT visualization algorithm for fast and easy detection of skull fractures.

PURPOSE To retrospectively assess the rate of detection of skull fractures at cranial computed tomography (CT) achieved with the use of curved maximum intensity projections (MIPs) compared with that achieved by reading transverse sections only. MATERIALS AND METHODS The institutional review board approved this research and waived informed consent. A curved thin (3-mm) MIP of the skull cap and a curved thick (50-mm) MIP of the skull base were obtained from the cranial CT data in 200 consecutive patients with head trauma. Four radiologists (two residents without experience in cranial CT and two consultants) independently evaluated all cases. Each radiologist reported findings in 100 patients by using transverse sections only and findings in the other 100 patients by using the unfolded view. The radiologists were blinded to patient names, and patient and group orders were randomized. The results were compared with a standard of reference established by two experts from all prior reading results, all reconstructions, and high-spatial-resolution multiplanar reformats. Logistic regression with repeated measurements was used for statistical analysis. RESULTS The experts found 63 fractures in 30 patients. When transverse sections only were used, the mean patient-based fracture detection rate was 43% (13 of 30) for inexperienced and 70% (21 of 30) for experienced readers; with curved MIPs, the rates were 80% (24 of 30) and 87% (26 of 30), respectively. Overall sensitivity was higher with curved MIPs (P < .001); specificity was higher with transverse sections (P < .001). CONCLUSION Curved MIPs enable a significantly higher fracture detection rate than transverse sections. They also considerably close the experience gap in fracture detection rate between residents and experts.

Neuroendocrine tumor of the common hepatic duct, mimicking a choledochal cyst in a 6-year-old child

We report a rare case of a neuroendocrine tumor of the extrahepatic biliary tree in a child. A 6-year-old girl who presented with jaundice and pruritus was found to have elevated liver enzymes along with a cystic dilatation of the common hepatic duct. After further diagnostic testing, a working diagnosis of a type I choledochal cyst was established. Laparotomy revealed hydrops of the gall bladder, an elongated and dilated cystic duct and a cystic dilatation of the common hepatic duct. An unusually thickened common bile duct was also noted at the time. Follow-up histology revealed an invasive neuroendocrine tumor which lead to a second look operation in which extended resection and lymphadenectomy was performed. No histological or gross pathological evidence of lymph node metastasis was found. Postoperatively the patient continues doing well 2 years after the original diagnosis was established. Neuroendocrine tumors of the extrahepatic bile duct are extremely rare with only 4 pediatric cases of a total of 51 cases published in the literature. To our knowledge, this is the youngest patient reported so far. The rarity of this entity made it challenging to diagnose a case of a neuroendocrine tumor in an atypical location that radiologically mimicked a choledochal cyst.

Sustained cognitive benefit 5 years after carotid endarterectomy

OBJECTIVES This study investigated the long-term effect of carotid endarterectomy (CEA) on cognitive brain function by means of P300 evoked potentials. METHODS Twenty-five consecutive patients (36% women) with a median age of 68 years underwent CEA with a median degree of stenosis of 90%. Cognitive brain function was objectively measured by means of P300 auditory evoked potentials (peak latencies in milliseconds [ms]) before CEA, at discharge, and at 1 and 5 years. Values were compared with 25 age- and sex-matched healthy individuals. RESULTS Cognitive P300 evoked potentials were prolonged (ie, impaired) in patients before CEA compared with controls (vertex [Cz], 384 +/- 52 vs 357 +/- 16 ms, P = .020]. At 1 year, P300 evoked potentials were significantly shortened (ie, improved) in patients after CEA compared with baseline values [Cz, 371 +/- 38 vs 384 +/- 52 ms, P = .010]. Furthermore, no difference between patients after CEA and controls was observed [Cz, 371 +/- 38 vs 360 +/- 14 ms, P = .21]. This effect was sustained at 5 years, and P300 evoked potentials continued to be significantly shortened (ie, improved) in patients after CEA compared with baseline values [Cz, 367 +/- 39 vs 384 +/- 52 ms, P = .040]. Continuing, no difference between patients after CEA and controls could be observed [Cz, 367 +/- 39 vs 362 +/- 17 ms, P = .58]. These results could be confirmed in repeated measures analysis of variance for Cz (P = .025) and frontal (Fz) results (P = .018). CONCLUSIONS CEA improves previously impaired cognitive brain function as shown by P300 measurements similar to normal cognitive brain function of age- and sex-matched healthy individuals. This beneficial effect is sustained up to 5 years after treatment.

Maternal smoking and fetal lung volume—an in utero MRI investigation

To investigate whether fetal lung volume and fetal lung volume growth over gestation are different in mothers who reported smoking during pregnancy compared to non‐smoking controls.

Non-occlusive mesenteric ischaemia in out of hospital cardiac arrest survivors.

Background and aim of the study: Non-occlusive mesenteric ischaemia (NOMI) is characterised by hypoperfusion of the intestines without evidence of mechanical obstruction, potentially leading to extensive ischaemia and necrosis. Low cardiac output appears to be a major risk factor. Cardiopulmonary resuscitation aims at restoring blood flow after cardiac arrest. However, post restoration of spontaneous circulation, myocardial stunning limits immediate recovery of sufficient cardiac function. Since after successful cardiopulmonary resuscitation patients are often ventilated and sedated, NOMI might be underdiagnosed and potentially life-saving treatment delayed. Material and methods: A prospectively maintained multi-purpose cohort of out of hospital cardiac arrest survivors, who had successful restoration of spontaneous circulation, was used for this retrospective database analysis. Patients’ charts were screened for clinical, radiological or pathological evidence of NOMI and clinical data were collected. Results: Between 2000 and 2014, 1780 patients who were successfully resuscitated after out of hospital cardiac arrest were screened for NOMI. Twelve patients (0.68 %) suffered from NOMI and six of those died (50 %). Patients suffering from NOMI tended to have a longer duration until restoration of spontaneous circulation (27 vs. 20 min, p=0.128) and had significantly higher lactate (14 mmol/l vs. 8 mmol/l, p=0.002) and base deficit levels at admission (−17 vs. −10, p=0.012). Median leukocyte counts in NOMI patients peaked at the day of diagnosis. Conclusion: NOMI is a rare but life-threatening and potentially curable complication following successful cardiopulmonary resuscitation. Lactate and base deficit at admission could help to identify patients at risk for developing NOMI who might benefit from increased clinical attention.

Automated tube voltage selection in pediatric non-contrast chest CT

Background Modern CT scanners provide automatic dose adjustment systems, which are promising options for reducing radiation dose in pediatric CT scans. Their impact on patient dose, however, has not been investigated sufficiently thus far. Objective To evaluate automated tube voltage selection (ATVS) in combination with automated tube current modulation (ATCM) in non-contrast pediatric chest CT, with regard to the diagnostic image quality. Materials and methods There were 160 non-contrast pediatric chest CT scans (8.7±5.4 years) analyzed retrospectively without and with ATVS. Correlations of volume CT Dose Index (CTDIvol) and effective diameter, with and without ATVS, were compared using Fisher’s z-transformation. Image quality was assessed by mean signal-difference-to-noise ratios (SDNR) in the aorta and in the left main bronchus using the independent samples t-test. Two pediatric radiologists and a general radiologist rated overall subjective Image quality. Readers’ agreement was assessed using weighted kappa coefficients. A p value <0.05 was considered significant. Results CTDIvol correlation with the effective diameter was r = 0.62 without and r = 0.80 with ATVS (CI: -0.04 to -0.60; p = 0.025). Mean SDNR was 10.88 without and 10.03 with ATVS (p = 0.0089). Readers’ agreement improved with ATVS (weighted kappa between pediatric radiologists from 0.1 (0.03–0.16) to 0.27 (0.09–0.45) with ATVS; between general and each pediatric radiologist from 0.1 (0.06–0.14) to 0.12 (0.05–0.20), and from 0.22 (0.11–0.34) to 0.36 (0.24–0.49)). Conclusion ATVS, combined with ATCM, results in a radiation dose reduction for pediatric non-contrast chest CT without a loss of diagnostic image quality and prevents errors in manual tube voltage setting, and thus protecting larger children against an unnecessarily high radiation exposure.