Initial experience with dual-layer detector spectral CT for diagnosis of blood or contrast after endovascular treatment for ischemic stroke

Purpose: To determine whether spectral detector CT (SDCT) with a plain non-enhanced monochromatic CT, a water-weighted image after iodine removal, an iodine map, and Mono energetic images changes the diagnosis and classification of intracranial hemorrhage based on single energy CT after endovascular treatment (EVT) for ischemic stroke. Methods: Two readers evaluated single energy and SD CT data collected from 63 patients within one week after EVT. They diagnosed ICH or contrast staining, and graded ICH according to the Heidelberg and Safe Implementation of Thrombolysis in Stroke–Monitoring Study (SITS-MOST) classification. Differences in diagnosis between single energy and SD CT were tested with Pearson's chi-squared test. Diagnostic values of single energy CT were calculated. Interrater agreement was based on Cohen’s Kappa. Results: When spectral data were added to single energy CT, the diagnosis of ICH changed in 8 CT scans (13%): in 4, the diagnosis of ICH was rejected and in 4, initially undetected ICH was diagnosed. In an additional 3 patients, the ICH grade was modified. CT alone had 88% sensitivity, 87% specificity, 88% positive diagnostic value, 87% negative diagnostic value, and 87% overall accuracy for ICH compared to SDCT. Interreader agreement on the presence of ICH was 0.84 (95% CI 0.51–0.86) for spectral CT and 0.84 (95% CI 0.73–0.97) for single energy CT. Conclusion: SD CT after endovascular treatment contributes to the distinction between intracranial hemorrhage and contrast staining

Colorectal liver metastases: CT, MR imaging, and PET for diagnosis - Meta-analysis

PURPOSE: To perform a meta-analysis to obtain sensitivity estimates of computed tomography (CT), magnetic resonance (MR) imaging and fluorine 18 fluorodeoxy- , glucose (FDG) positron emission tomography (PET) for detection of colorectal liver metastases on per-patient and per-lesion bases. MATERIALS AND METHODS: MEDLINE, EMBASE, Web of Science and CANCERLIT, databases and Cochrane Database of Systematic Reviews were searched for including original articles published from January 1990 to December 2003. Criteria for inclusion of articles were as follows: Articles were reported in the English German or,, French language; CT, MR imaging, or FDG PET was performed to identify and characterize colorectal liver metastases; histopathologic analysis (surgery, biopsy, or autopsy), intraoperative observation (manual palpatation, intraoperative ultrasonography [US]), and/or follow-up US was the reference standard; and data were sufficient for calculation of true-positive or false-negative values. A random-effects linear regression model was used to obtain sensitivity estimates in assessment of liver metastases. RESULTS: Of 165 identified relevant articles, 61 fulfilled all inclusion criteria Sen. sitivity estimates on a per-patient basis for nonhelical CT, helical CT, 1.5-T MR imaging, and FDG PET were 60.2%, 64.7%, 75.8%, and 94.6%, respectively; FDG PET was the most accurate modality. On a per-lesion basis, sensitivity estimates for nonhelical CT, helical CT, 1.0-T MR imaging, 1.5-T MR imaging, and FDG PET were 52.3%, 63.8%, 66.1%, 64.4%, and 75.9%, respectively; nonhelical CT had lowest sensitivity. Estimates of gadolinium-enhanced MR imaging and superparamagnetic iron oxide (SPIO)-enhanced MR imaging were significantly better, compared with nonenhanced MR imaging (P =.019 and P <.001, respectively) and with helical CT with 45 g of iodine or less (P =.02 and P <.001, respectively). For lesions of I cm or larger, SPIO-enhanced MR imaging was the most accurate modality (P <.001). CONCLUSION: FDG PET had significantly higher sensitivity on a per-patient basis, compared with that of the other modalities, but not on a per-lesion basis. Sensitivity estimates for MR imaging with contrast agent were significantly superior to those for helical CT with 45 g of iodine or less. (c) RSNA, 200

Tailored imaging of islet cell tumors of the pancreas amidst increasing options

Pancreatic islet cell tumors are neuroendocrine tumors, which can produce hormones and can arise as part of multiple endocrine neoplasia type 1 or von-Hippel-Lindau-disease, two genetically well-defined hereditary cancer syndromes. Currently, technical innovation improves conventional and specific molecular imaging techniques. To organize the heterogeneous results described for the imaging of these tumors, we distinguished three indications (1) imaging of a patient with hormone hypersecretion, (2) search for a pancreatic primary in case of proven neuroendocrine cancer of unknown primary, and (3) screening of asymptomatic mutation carriers. We searched for publications on imaging of islet cell tumors between 1995 and January 2010 and defined a Level of Evidence (LOE) for the applicability of each technique. For each technique, data were analyzed in a Forest plot and arranged per imaging indication and tumor subtype.LOEs are weak for all imaging techniques. Analyses indicate a prominent role for endoscopic ultrasound for all three indications. (C) 2011 Elsevier Ireland Ltd. All rights reserved

Diagnosing internal herniation after Roux-en-Y gastric bypass surgery: Literature overview, cadaver study and the added value of 3D CT angiography

Purpose The purposes of the study are to outline the complexity of diagnosing internal herniation after Roux-en-Y gastric bypass (RYGB) surgery and to investigate the added value of computed tomography angiography (CTA) for diagnosing internal herniation. Materials and Methods A cadaver study was performed to investigate the manifestations of internal hernias and mesenteric vascularization. Furthermore, a prospective, ethics approved study with retrospective interpretation was conducted. Ten patients, clinically suspected for internal herniation, were prospectively included. After informed consent was obtained, these subjects underwent abdominal CT examination, including additional arterial phase CTA. All subjects underwent diagnostic laparoscopy for suspected internal herniation. The CTA was used to create a 3D reconstruction of the mesenteric arteries and surgical staples (3D CTA). The 3D CTA was interpreted, taking into account the presence and type of internal hernia that was found upon laparoscopy. Results Cadaveric analysis demonstrated the complexity of internal herniation. It also confirmed the expected changes in vascular structure and surgical staple arrangement in the presence of internal herniation. 3D CTA studies of the subjects with active internal hernias demonstrated remarkable differences when compared to control 3D CTA studies. The blood supply of herniated intestinal limbs in particular showed abnormal trajectories. Additionally, enteroenterostomy staple lines had migrated or altered orientation. Conclusion 3D CTA is a promising technique for diagnosing active internal hernias. Our findings suggest that for diagnosing internal hernias, focus should probably shift from routine abdominal CT examination towards the 3D assessment of the mesenteric vasculature and surgical staples