1,912 research outputs found
Ovarian Cancer Diagnosis and Staging
This unit presents a basic protocol for detecting and staging ovarian cancer. The techniques are similar to those used for general imaging of the liver/abdomen and the pelvis for other applications.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145251/1/cpmia2002.pd
Hepatic MRI for GE Scanners
MRI techniques continue to evolve rapidly, but the basic components of a liver examination, and the clinical role of each component, have changed little. The three most important considerations for choosing techniques for imaging the liver continue to be contrast, motion artifact, and coverage. This unit presents a for liver imaging for General Electric (GE) scanners. However, these basic approaches to hepatic MR imaging are quite similar, with most details relating to minor vendorāspecific differences.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145282/1/cpmia1502.pd
US and MR imaging features of benign cystic mesothelioma of the liver: A diagnostic dilemma
Cystic mesotheliomas are benign neoplasms, often seen in the parietal and visceral peritoneum, omentum and pelvic organs, and are exceedingly rare in the liver. It is however important to be familiar with the radiological findings of this tumour because the signal-intensity and enhancement pattern of this tumor are unusual and not typical for any of the more frequently seen mass lesions. In our patient, characteristic imaging findings on dynamic contrast-enhanced MRI and histopathological confirmation with appropriate immunohistochemical markers facilitated a correct diagnosis. We herein describe the clinical, imaging and histopathological features, pathogenesis, differential diagnosis and treatment of benign cystic mesothelioma involving posterior segment of the right lobe of the liver
Oxygen ion dynamics in the Earth's ring current: Van Allen probes observations
Oxygen (O+) enhancements in the inner magnetosphere are often observed during geomagnetically active times, such as geomagnetic storms. In this study, we quantitatively examine the difference in ring current dynamics with and without a substantial O+ ion population based on almost 6 years of Van Allen Probes observations. Our results have not only confirmed previous finding of the role of O+ ions to the ring current but also found that abundant O+ ions are always present during large storms when sym-H < -60 nT without exception, whilst having the pressure ratio () between O+ and proton (H+) larger than 0.8 and occasionally even larger than 1 when L < 3. Simultaneously, the pressure anisotropy decreases with decreasing sym-H and increasing L shell. The pressure anisotropy decrease during the storm main phase is likely related to the pitch angle isotropization processes. In addition, we find that increases during the storm main phase and then decreases during the storm recovery phase, suggesting faster buildup and decay of O+ pressure compared to H+ ions, which are probably associated with some species dependent source and/or energization as well as loss processes in the inner magnetosphere.Accepted manuscrip
Paraumbilical collateral veins on MRI as possible protection against portal venous thrombosis in candidates for liver transplantation
Background: We retrospectively evaluate the potential protective influence of patent paraumblical vein (PUV) collaterals against portal vein (PV) thrombosis and reduced PV diameter in candidates for orthotopic liver transplant (OLT)
Methods: Dynamic 3D contrast-enhanced MRI at 1.5T was obtained in 309 patients with cirrhosis without evidence of malignancy. All MR studies were reviewed by one reader for PUV collaterals, PV thrombosis and PV diameter. Statistical analysis was performed by Fisher exact tests; 50 selected studies were reviewed independently by two additional readers to determine interobserver agreement via intraclass correlation coefficient (ICC).
Results: Patent PUV was noted in 119 of 309 patients (38.5%). Mean PV diameter was 13.4 Ā± 3.0 mm in patients with PUV compared with 11.3 Ā± 3.6 mm without PUV (P \u3c 0.01). Main PV thrombosis was present in 13 of 309 patients (4.2%) and significantly more frequent in those without PUV than with PUV (6.3% vs. 0.8%, P \u3c 0.05). ICC indicated almost perfect agreement among three readers for presence of PUV collaterals (ICC = 0.91) and PV thrombosis (ICC = 0.96).
Conclusion: Our results suggest that patients with patent PUV appear less likely to develop main PV thrombosis or small PV diameter, suggesting a protective effect of PUV on PV patency
Liver imaging reporting and data system: An expert consensus statement
The increasing incidence and high morbidity and mortality of hepatocellular carcinoma (HCC) have inspired the creation of the Liver Imaging Reporting and Data System (LI-RADS). LI-RADS aims to reduce variability in exam interpretation, improve communication, facilitate clinical therapeutic decisions, reduce omission of pertinent information, and facilitate the monitoring of outcomes. LI-RADS is a dynamic process, which is updated frequently. In this article, we describe the LI-RADS 2014 version (v2014), which marks the second update since the initial version in 2011
Does case misclassification threaten the validity of studies investigating the relationship between neck manipulation and vertebral artery dissection stroke? No
Background: The purported relationship between cervical manipulative therapy (CMT) and stroke related to vertebral artery dissection (VAD) has been debated for several decades. A large number of publications, from case reports to caseācontrol studies, have investigated this relationship. A recent article suggested that case misclassification in the caseācontrol studies on this topic resulted in biased odds ratios in those studies. Discussion: Given its rarity, the best epidemiologic research design for investigating the relationship between CMT and VAD is the caseācontrol study. The addition of a case-crossover aspect further strengthens the scientific rigor of such studies by reducing bias. The most recent studies investigating the relationship between CMT and VAD indicate that the relationship is not causal. In fact, a comparable relationship between vertebral artery-related stroke and visits to a primary care physician has been observed. The statistical association between visits to chiropractors and VAD can best be explained as resulting from a patient with early manifestation of VAD (neck pain with or without headache) seeking the services of a chiropractor for relief of this pain. Sometime after the visit the patient experiences VAD-related stroke that would have occurred regardless of the care received. This explanation has been challenged by a recent article putting forth the argument that case misclassification is likely to have biased the odds ratios of the caseācontrol studies that have investigated the association between CMT and vertebral artery related stroke. The challenge particularly focused on one of the caseācontrol studies, which had concluded that the association between CMT and vertebral artery related stroke was not causal. It was suggested by the authors of the recent article that misclassification led to an underestimation of risk. We argue that the information presented in that article does not support the authorsā claim for a variety of reasons, including the fact that the assumptions upon which their analysis is based lack substantiation and the fact that any possible misclassification would not have changed the conclusion of the study in question. Conclusion: Current evidence does not support the notion that misclassification threatens the validity of recent caseācontrol studies investigating the relationship between CMT and VAD. Hence, the recent re-analysis cannot refute the conclusion from previous studies that CMT is not a cause of VAD.https://doi.org/10.1186/s12998-016-0124-
The Permanence of the Visual Recovery that Follows Reverse Occlusion of Monocularly Deprived Kittens
While the behavioral and physiologic effects of an early period of monocular deprivation can be extremely severe, they are not necessarily irreversible. Considerable recovery can occur if visual input is restored to the deprived eye sufficiently early, particularly if the nondeprived eye is occluded at the same time (reverse occlusion). This study examines the permanence of the visual recovery promoted by a period of reverse occlusion in kittens that were monocularly deprived from near birth for periods ranging from 3 to 18 weeks. During the period of reverse occlusion, the vision of the initially deprived eye improved from apparent blindness to good levels of acuity. However, upon restoring visual input to the formerly nondeprived eye a surprisingly rapid and reciprocal change occurred in the visual acuity of both eyes. Much of the substantial gain in the vision of the initially deprived eye that occurred during reverse occlusion was lost within 3 weeks, while at the same time the vision of the initially nondeprived eye improved substantially. Nevertheless, in many animals the acuity of the initially nondeprived eye did not recover to levels it had reached prior to reverse occlusion. These results hold important implications for the nature of the mechanisms responsible for the dramatic physiologic effects of monocular occlusion and reverse occlusion on the visual cortex. The results also may help elucidate recent observations on patching therapy in human amblyopia. Invest Ophthalmol Vis Sci 25: [908][909][910][911][912][913][914][915][916][917] 1984 The behavioral and physiologic consequences of early monocular deprivation by eyelid closure have been explored extensively in both cats and monkeys
Dilated cisternae chyli. A sign of uncompensated cirrhosis at MR imaging
Background: To retrospectively determine the frequency of dilated cisterna chyli (CC) on MR images in patients with cirrhosis, and to assess its value as a simple diagnostic imaging sign of uncompensated cirrhosis.
Methods: Study population included 257 patients (149 with pathologically proved cirrhosis and 108 control subjects without history of chronic liver diseases) who had 1.5T MR imaging. Cirrhosis patients were divided into compensated and uncompensated groups. Three independent observers qualitatively evaluated visibility of CC 2mm or greater in transverse diameter, identified as a tubular structure with fluid signal intensity (SI). CC diameters greater than 6 mm were defined as dilated. Statistical analysis was performed by Student t test and interobserver agreement via intraclass correlation coefficient (ICC).
Results: CCs with diameter 2 mm or more were recorded in 113 of 149 (76%) cirrhotic patients and 15 of 108 (14%) control subjects (P\u3c 0.001). Dilated CCs were significantly more frequent in uncompensated than compensated cirrhotic patients (54% vs 5%, P\u3c0.001). The sensitivity, specificity, accuracy, and positive predictive value of dilated CC for uncompensated cirrhosis were 54%, 98%, 80%, and 96%, respectively.
Conclusion: Dilated CC can be used as a simple and specific sign complimentary to other findings of uncompensated cirrhosis
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