Pericarditis associated with ulcerative colitis and Crohn's disease

Extracolonic manifestations of inflammatory bowel disease are common and diverse. However, cardiac complications are unusual and we therefore wish to report two cases in which pericarditis occurred. The first was a patient with Crohn's disease of the colon, in whom the pericarditis developed postoperatively. In the second case an acute pericarditis came on simultaneously with the initial presentation of ulcerative colitis.     

Macrolipasemia: a rare cause of persistently elevated serum lipase

This report describes a variant form of lipase found in a patient with cryptogenic liver cirrhosis. Serum lipase in this patient showed persistently increased activity with simultaneously normal activity of amylase. Results of exclusion chromatography demonstrate that the lipase activity in the serum of this patient eluted as a macromolecule. Since macromolecular complexes were not fixed by protein A, it seems unlikely that lipase is attached to IgG. Tests of the sera from 20 patients with raised serum lipase activity in acute pancreatitis or an acute episode of chronic pancreatitis revealed, in two patients, that a small but reproducible proportion of the total lipase activity eluted in the region of the macrolipase. In addition, 10% and 18% of the total lipase activity was found in the elution region of the macrolipase in two commercial pooled sera used for quality control. The results show that, in rare cases, macrolipasemia must be considered a possible cause of raised serum lipase activity.     

Effects of Piperonyl Butoxide on Drug Metabolism in Rodents and Man

Piperonyl butoxide is a potent inhibitor of microsomal enzyme function in mice, as measured by this compound’s ability to inhibit in vivo antipyrine metabolism and to prolong the actions of pentobarbital and zoxazolamine (Flexin). in rats, however, a very high dose of piperonyl butoxide is needed for inhibition of antipyrine and benzo[a]pyrene metabolism and for potentiation of pentobarbital and zoxazolamine action. Rats require more than a hundredfold higher dose of piperonyl butox ide than mice for inhibiting antipyrine metabolism. Studies in man revealed that oral administration of 0.71 mg of piperonyl butoxide per kilogram of body weight did not influence antipyrine metabolism. Since this dose is considerably greater than the daily exposure of individuals using sprays extensively in enclosed areas, it is unlikely that environmental exposure to piperonyl butoxide inhibits human microsomal enzyme function.     

Memantine upregulates BDNF and prevents dopamine deficits in SIV-infected macaques: a novel pharmacological action of memantine.

N-methyl-D-aspartate (NMDA) receptor activation is involved in the pathogenetic cascades of neurodegenerative disorders including human immunodeficiency virus (HIV) dementia. Memantine, an uncompetitive NMDA receptor antagonist, which has been recently approved for the treatment of Alzheimer's disease, is being discussed as a potential adjunctive therapeutic substance for HIV dementia. We used simian immunodeficiency virus-infected rhesus macaques to assess the effects of memantine on brain dysfunction and brain pathology within 3-5 months after initial infection during early asymptomatic stage of disease. We had shown previously that within this time frame, marked changes were evident in the dopaminergic systems. Memantine was administered two weeks post infection, at peak viremia, in order to prevent early NMDA receptor activation due to immune mediators. We found that memantine prevented onset of dopamine deficits in the brains of SIV-infected macaques, without affecting early brain pathology or peripheral course of infection. Memantine specifically upregulated mRNA and protein expression of the neurotrophic factor brain-derived neurotrophic factor (BDNF), suggesting that the protective effect of memantine on dopamine function may be mechanistically remote from NMDA receptor antagonism. This novel pharmacological action of memantine may also be relevant for other neurodegenerative disorders and supports the involvement of neurotrophic factors in adult brain neuroprotection.     

Max CAPR: High‐resolution 3D contrast‐enhanced MR angiography with acquisition times under 5 seconds

High temporal and spatial resolution is desired in imaging of vascular abnormalities having short arterial‐to‐venous transit times. Methods that exploit temporal correlation to reduce the observed frame time demonstrate temporal blurring, obfuscating bolus dynamics. Previously, a Cartesian acquisition with projection reconstruction‐like (CAPR) sampling method has been demonstrated for three‐dimensional contrast‐enhanced angiographic imaging of the lower legs using two‐dimensional sensitivity‐encoding acceleration and partial Fourier acceleration, providing 1mm isotropic resolution of the calves, with 4.9‐sec frame time and 17.6‐sec temporal footprint. In this work, the CAPR acquisition is further undersampled to provide a net acceleration approaching 40 by eliminating all view sharing. The tradeoff of frame time and temporal footprint in view sharing is presented and characterized in phantom experiments. It is shown that the resultant 4.9‐sec acquisition time, three‐dimensional images sets have sufficient spatial and temporal resolution to clearly portray arterial and venous phases of contrast passage. It is further hypothesized that these short temporal footprint sequences provide diagnostic quality images. This is tested and shown in a series of nine contrast‐enhanced MR angiography patient studies performed with the new method. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Carotid artery: elliptic centric contrast-enhanced MR angiography compared with conventional angiography

PURPOSE: To determine the accuracy of elliptic centric contrast material-enhanced magnetic resonance (MR) angiography by using conventional angiography as the reference standard. MATERIALS AND METHODS: Fifty patients were examined prospectively with contrast-enhanced MR angiography and conventional angiography. The two examinations were performed within 1 week of each other. Two patients underwent conventional angiography of only one carotid artery, which yielded 98 arteries for comparison. RESULTS: With conventional angiography as the reference standard and by using a 70% threshold for internal carotid arterial diameter stenosis, maximum intensity projection (MIP) images had a sensitivity of 93.3%, specificity of 85.1%, and accuracy of 87.6%, whereas reformatted transverse source images had a sensitivity of 83.3%, specificity of 97.0%, and accuracy of 92.8%. Interobserver variability for conventional angiograms was 0.97, for MIP images was 0.91, and for source images was 0.90. The contrast-enhanced MR angiographic technique had a sensitivity of 88.9% and specificity of 58.1% for the presence of irregularity and/or ulceration. All 50 examinations were triggered appropriately so that minimal or no venous signal intensity was depicted. CONCLUSION: Contrast-enhanced elliptic centric three-dimensional MR angiography offers high-spatial-resolution, venous-suppressed images of the carotid arteries that appear to be adequate to replace conventional angiography in most patients examined prior to carotid endarterectomy.     

High-spatial-resolution contrast-enhanced MR angiography of the renal arteries: a prospective comparison with digital subtraction angiography

PURPOSE: To evaluate a high-spatial-resolution three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiographic technique for detecting proximal and distal renal arterial stenosis. MATERIALS AND METHODS: Twenty-five patients underwent high-spatial-resolution small-field-of-view (FOV) 3D contrast-enhanced MR angiography of the renal arteries, which was followed several minutes later by more standard, large-FOV 3D contrast-enhanced MR angiography that included the distal aorta and iliac arteries. For both acquisitions, MR fluoroscopic triggering and an elliptic centric view order were used. Two readers evaluated the MR angiograms for grade and hemodynamic significance of renal arterial stenosis, diagnostic quality, and presence of artifacts. MR imaging results for each patient were compared with those of digital subtraction angiograms. RESULTS: The high-spatial-resolution small-FOV technique provided high sensitivity (97%) and specificity (92%) for the detection of renal arterial stenosis, including all four distal stenoses encountered. The portrayal of the segmental renal arteries was adequate for diagnosis in 19 (76%) of 25 patients. In 12% of the patients, impaired depiction of the segmental arteries was linked to motion. CONCLUSION: The combined high-spatial-resolution small-FOV and large-FOV MR angiographic examination provides improved spatial resolution in the region of the renal arteries while maintaining coverage of the abdominal aorta and iliac arteries.     

Time‐resolved dual‐station calf–foot three‐dimensional bolus chase MR angiography with fluoroscopic tracking

Purpose:

To refine, adapt, and evaluate the technical aspects of fluoroscopic tracking for generating dual‐station high‐spatial‐resolution MR angiograms of the calves and feet using a single injection of contrast material.

Materials and Methods:

Nine subjects (seven healthy volunteers followed by two patients) were imaged using a two‐station calf–foot three‐dimensional time‐resolved bolus chase MR angiography protocol which provided <1.0 mm³ spatial resolution throughout and 2.5‐ and 6.6‐s frame times at the calf and foot stations, respectively. Real‐time reconstruction of calf station time frames allowed visually guided triggering of table advance to the foot station. The studies were independently read and scored by two radiologists in six image quality categories.

Results:

On average, overall diagnostic quality at the calf and foot stations was good‐to‐excellent, the calf arteries and all but the smallest foot arteries had good‐to‐excellent signal and sharpness, artifact and venous contamination were minor, and signal continuity across the inter‐station interface was good.

Conclusion:

The feasibility of fluoroscopic tracking has been demonstrated as an efficient approach for high spatiotemporal imaging of the arteries of the calves and feet with good‐to‐excellent diagnostic quality and low degrading venous contamination. J. Magn. Reson. Imaging 2012;36:1168–1178. © 2012 Wiley Periodicals, Inc.     

Centric phase-encoding order in three-dimensional MP-RAGE sequences: application to abdominal imaging.

Three-dimensional (3D) magnetization-prepared rapid gradient-echo imaging has been proposed as a method for improving signal-to-noise ratio (S/N) and contrast-to-noise ratio (C/N) in rapid abdominal imaging. Originally, a standard sequential phase-encoding order was proposed. In the present study, two approaches to a 3D centric phase-encoding order are presented: (a) application of the two-dimensional (2D) centric order to one of the 3D encoding directions, and (b) an interleaved square spiral order, which is the segmented 3D analog of the 2D centric order. With use of simulation, phantom, and volunteer results, the proposed 3D centric methods are compared in terms of S/N, C/N, and artifacts to the 3D sequential method and 2D magnetization-prepared methods. The second centric approach was found to be superior to the first; however, in general, the 3D technique was found to be inferior to the 2D technique for abdominal imaging because of motion artifact in the 3D image set caused by misregistration among the multiple breath holds required.