Magnetic resonance imaging assessment of spinal inflammation in patients treated for ankylosing spondylitis.

OBJECTIVE: To compare different magnetic resonance imaging (MRI) based algorithms for assessment of spinal inflammation in patients with ankylosing spondylitis (AS) being treated with disease modifying drugs. METHODS: Eleven patients (10 men, 1 woman) who fulfilled modified New York diagnostic criteria and had severe disease [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) > 4] were given intravenous infusion of infliximab (Remicade, 5 mg/kg) for 96 weeks. Whole-spine MRI was done at 0, 24, and 54 weeks. Measurements of the Ankylosing Spondylitis Spinal MRI Activity Score (ASspiMRI), paravertebral inflammatory lesion count (pILC), contrast:noise ratio (CNR) measurements of defined inflammatory lesions, and other scores together with C-reactive protein concentration were made at each visit. Examinations were anonymized and randomly presented twice to 2 radiologists. The significance of any changes in scores, their correlation with the BASDAI, and interobserver and intraobserver correlations were calculated. RESULTS: The mean (+/- SD) BASDAI improved from 7.2 (+/- 1.5) to 1.3 (+/- 0.9) after 54 weeks (p < 0.001), and the ASspiMRI score improved from 12.0 (+/- 8.0) to 0.2 (+/- 0.5) (p < 0.001). Correlations between ASspiMRI score and BASDAI were 0.831, 0.746, and 0.369 (p < 0.001 each). The pILC improved significantly (p < 0.01). CNR showed no correlation with any clinical score. CONCLUSION: The ASspiMRI score performed best for assessment and quantification of spinal inflammation and disease activity in patients with AS, but should also quantify paravertebral inflammatory lesions, since we could show that this will significantly improve its correlation to clinical scores and increase its sensitivity to mild inflammatory processes.

Serum S-100B concentration provides additional information fot the indication of computed tomography in patients after minor head injury: a prospective multicenter study.

Ninety percent of patients with minor head injury (MHI) who have cranial computed tomography (CCT) under the present clinical decision rules have normal scans. Serum concentrations of the astroglial protein S-100B were recently found to provide useful information, but these studies were too small to provide a statistically safe basis for changing the present rule. We have investigated whether S-100B concentrations in patients with MHI can provide additional information to improve indication of the need for an initial CCT scan. One thousand three hundred nine patients with MHI were enrolled in this prospective, multicenter study. All had a CCT scan to confirm diagnosis in accordance with the present clinical decision rules. S-100B was measured in serum samples obtained upon admission. Data were analyzed using contingency table and receiver operating characteristic curve and compared with those for healthy donors (n = 540) and with those for patients with moderate to severe head injury (n = 55). Of the 1309 patients studied, 93 exhibited trauma-relevant intracerebral lesions on the CCT scan (CCT+). With a cutoff limit of 0.10-microg/L S-100B (95th percentile of values in healthy volunteers), CCT+ patients were identified with a sensitivity level of 99% (95% confidence interval, 96% - 100%) and a specificity level of 30% (95% confidence interval, 29% - 31%). Adding the measurement of S-100B concentration to the clinical decision rules for a CCT scan in patients with MHI could allow a 30% reduction in scans. A prospective study of the clinical value of S-100B measurement in such patients is now under way.

Hard disk online caches in picture archiving and communication systems archives: how big is beautiful?

The objective of our study was to support algorithmic recommendations for the appropriate sizing of picture archiving and communication system (PACS) caches. For a large PACS installation, a detailed analysis of current radiographic (CR), CT and MRI studies (n=400 consecutive studies, respectively) was performed. In this process every available prior examination was also considered. A new algorithmic procedure for appropriate sizing of PACS caches was developed and applied to the given cache implementation. The number of all priors was 7.6+/-12.3. Of them, 61% were relevant priors with an average age of 203+/-385 days. A basic cache (BC) that covers 12 months of current imaging results in a pre-fetching quote of 15.4% (8.6% for 24 months). In the PACS installation examined, a minimal threefold increase in cache capacity was recommended. Studies that are retrieved, prior to viewing, from the long-term archive require additional space in the extended cache (EC). An intimate and mutual interaction between hospital information system (HIS), radiology information system (RIS) and PACS minimizes this requirement and increases the time during which actual image material from the BC is available online. A basic cache size covering actual imaging of 12 months up to 24 months is recommended. The parameters governing the individual dimensions of both cache spaces and a mathematical algorithm are demonstrated.

High-resolution MR imaging of human atherosclerotic femoral arteries in vivo: validation with intravascular ultrasound.

PURPOSE: To establish a magnetic resonance (MR) imaging protocol for noninvasive in-vivo analysis of atherosclerotic femoral artery segments in humans and to compare the results to those of intravascular ultrasonography (IVUS). MATERIALS AND METHODS: In seven patients with peripheral arterial occlusive disease, 20 femoral arterial segments per person were examined by high-resolution (HR) MR imaging and IVUS. Comparison was possible in 123 of 140 segments. MR imaging was performed at 1.5 T with use of a three-dimensional (3D) time-of-flight sequence with an in-plane resolution of 0.78 x 0.49 mm(2). 3D contrast-enhanced MR angiography was used for exact positioning of the HR MR imaging slices. IVUS (3.5 F, 40 MHz) was performed with use of a motorized pullback system. Parameters analyzed included cross-sectional lumen area (LA), vessel area (VA), and extent of vessel wall calcification. RESULTS: Agreement between IVUS and HR MR imaging was analyzed with use of the Bland-Altman method. The paired LA measurements were in close agreement: the Bland-Altman mean bias in LA was -0.4 mm with a precision of +/-5.1 mm (P =.062). As a result of dorsal echo extinction in IVUS, VA measurements were feasible in only 74 of 140 segments. VA measurements were moderately correlated (r = 0.74; P <.0001), and a 25% overestimation by HR MR imaging compared to IVUS was observed. Intra- and interobserver comparisons for LA and VA measured with HR MR imaging did not show significant differences. Vessel wall calcifications were classified with a sensitivity of 91%, a specificity of 93%, and an accuracy of 93%. CONCLUSIONS: The MR imaging protocol introduced in the present study permits precise assessment of LA and extent of calcification in peripheral arterial occlusive disease in vivo. HR MR imaging shows high concordance with IVUS and may have the potential for noninvasive therapy monitoring.