Red cell distribution width does not predict stroke severity or functional outcome.

INTRODUCTION: Red cell distribution width was recently identified as a predictor of cardiovascular and all-cause mortality in patients with previous stroke. Red cell distribution width is also higher in patients with stroke compared with those without. However, there are no data on the association of red cell distribution width, assessed during the acute phase of ischemic stroke, with stroke severity and functional outcome. In the present study, we sought to investigate this relationship and ascertain the main determinants of red cell distribution width in this population. METHODS: We used data from the Acute Stroke Registry and Analysis of Lausanne for patients between January 2003 and December 2008. Red cell distribution width was generated at admission by the Sysmex XE-2100 automated cell counter from ethylene diamine tetraacetic acid blood samples stored at room temperature until measurement. An χ(2) -test was performed to compare frequencies of categorical variables between different red cell distribution width quartiles, and one-way analysis of variance for continuous variables. The effect of red cell distribution width on severity and functional outcome was investigated in univariate and multivariate robust regression analysis. Level of significance was set at 95%. RESULTS: There were 1504 patients (72±15·76 years, 43·9% females) included in the analysis. Red cell distribution width was significantly associated to NIHSS (β-value=0·24, P=0·01) and functional outcome (odds ratio=10·73 for poor outcome, P<0·001) at univariate analysis but not multivariate. Prehospital Rankin score (β=0·19, P<0·001), serum creatinine (β=0·008, P<0·001), hemoglobin (β=-0·009, P<0·001), mean platelet volume (β=0·09, P<0·05), age (β=0·02, P<0·001), low ejection fraction (β=0·66, P<0·001) and antihypertensive treatment (β=0·32, P<0·001) were independent determinants of red cell distribution width. CONCLUSIONS: Red cell distribution width, assessed during the early phase of acute ischemic stroke, does not predict severity or functional outcome.

Acute Complications of Crohn's Disease: Comparison of Multidetector-Row Computed Tomographic Enterography with Magnetic Resonance Enterography.

Objective: To compare multidetector-row computed tomographic (MDCT) enterography with magnetic resonance (MR) enterography performed upon acute exacerbation of Crohn's disease. Subjects and Methods: Fifty-seven patients (mean age 33.5) with proven Crohn's disease and symptoms suggesting acute exacerbation were prospectively included. After oral administration of 1-2 liters of 5% methylcellulose, MDCT and MR enterography were performed on each patient (mean delay <24 h). Three radiologists blindly and independently evaluated each examination for technical quality and in terms of 8 pathological features of Crohn's disease. Observers' agreement, sensitivity and specificity resulted from comparison with the reference standard [surgery (n = 24), endoscopy (n = 17) and long-term follow-up (n = 16)]. Results: MDCT enterography demonstrated fewer artifacts than MR enterography (p < 0.0001). In 48 MDCT/MR enterography examinations, active disease was demonstrated: abscesses (n = 11), fistulas (n = 13), stenoses (n = 23) and/or intestinal inflammation (n = 38). Observers' agreement (range 0.56-0.87) was not significantly different between MDCT and MR enterography, neither in terms of sensitivity (range 58-95%) nor specificity (range 67-100%) for each of the 8 pathological features. Conclusion: Statistically, MR enterography is of similar diagnostic value as MDCT enterography for acute complications of Crohn's disease. Since the typical Crohn's disease patient is young and will very likely undergo life-long imaging, and given concerns about radiation exposure with MDCT, MR enterography should be the preferred modality.

CT dose optimization when changing to CT multi-detector row technology

The purpose of this article was to review the strategies to control patient dose in adult and pediatric computed tomography (CT), taking into account the change of technology from single-detector row CT to multi-detector row CT. First the relationships between computed tomography dose index, dose length product, and effective dose in adult and pediatric CT are revised, along with the diagnostic reference level concept. Then the effect of image noise as a function of volume computed tomography dose index, reconstructed slice thickness, and the size of the patient are described. Finally, the potential of tube current modulation CT is discussed.

Evaluation of peripheral arterial bypass grafts with multi-detector row CT angiography: comparison with duplex US and digital subtraction angiography.

PURPOSE: To assess the technical feasibility of multi-detector row computed tomographic (CT) angiography in the assessment of peripheral arterial bypass grafts and to evaluate its accuracy and reliability in the detection of graft-related complications, including graft stenosis, aneurysmal changes, and arteriovenous fistulas. MATERIALS AND METHODS: Four-channel multi-detector row CT angiography was performed in 65 consecutive patients with 85 peripheral arterial bypass grafts. Each bypass graft was divided into three segments (proximal anastomosis, course of the graft body, and distal anastomosis), resulting in 255 segments. Two readers evaluated all CT angiograms with regard to image quality and the presence of bypass graft-related abnormalities, including graft stenosis, aneurysmal changes, and arteriovenous fistulas. The results were compared with McNemar test with Bonferroni correction. CT attenuation values were recorded at five different locations from the inflow artery to the outflow artery of the bypass graft. These findings were compared with the findings at duplex ultrasonography (US) in 65 patients and the findings at conventional digital subtraction angiography (DSA) in 27. RESULTS: Image quality was rated as good or excellent in 250 (98%) and in 252 (99%) of 255 bypass segments, respectively. There was excellent agreement both between readers and between CT angiography and duplex US in the detection of graft stenosis, aneurysmal changes, and arteriovenous fistulas (kappa = 0.86-0.99). CT angiography and duplex US were compared with conventional DSA, and there was no statistically significant difference (P >.25) in sensitivity or specificity between CT angiography and duplex US for both readers for detection of hemodynamically significant bypass stenosis or occlusion, aneurysmal changes, or arteriovenous fistulas. Mean CT attenuation values ranged from 232 HU in the inflow artery to 281 HU in the outflow artery of the bypass graft. CONCLUSION: Multi-detector row CT angiography may be an accurate and reliable technique after duplex US in the assessment of peripheral arterial bypass grafts and detection of graft-related complications, including stenosis, aneurysmal changes, and arteriovenous fistulas.