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Arterial Segments (arterial + segment)
Selected AbstractsDiagnosis of arterial occlusive disease of the upper extremities: Comparison of color duplex sonography and angiographyJOURNAL OF CLINICAL ULTRASOUND, Issue 8 2003Muharrem Tola MD Abstract Purpose The aim of this study was to assess the abilities of color duplex sonography (CDUS) to detect and characterize arterial occlusive disease of the upper extremities. Methods We prospectively compared the results of CDUS with those of intra-arterial digital subtraction angiography, which were considered definitive, in patients with symptomatic arterial occlusive disease of the upper extremities. In each extremity, we visualized 9 arterial segments, which were each evaluated for stenoses and occlusions. Each segment was categorized on each imaging modality as not significantly narrowed (narrowed by <50%), significantly narrowed (narrowed by ,50% but <100%), or occluded (100%). Results We examined a total of 578 segments in 57 patients (34 men and 23 women) with a mean age of 50 years (range, 20,74 years). CDUS had a sensitivity, a specificity, a positive predictive value, a negative predictive value, and an accuracy of 98%, 99%, 97%, 99.5%, and 99%, respectively, for detecting occluded lesions and 79%, 100%, 100%, 99%, and 99%, respectively, for detecting hemodynamically significantly stenotic lesions. Notably, the sensitivity of CDUS for diagnosing significantly stenotic lesions (79%) was lower than that for diagnosing occlusive disease (98%). Conclusions With high sensitivity and accuracy rates, CDUS is a reliable screening method for detecting arterial occlusive disease of the upper extremities. This modality efficiently provides anatomic and hemodynamic data that are useful in cases of such disease. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:407,411, 2003 [source] 3D nongadolinium-enhanced ECG-gated MRA of the distal lower extremities: Preliminary clinical experienceJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2008FRANZCR, Ruth P. Lim MBBS Abstract Purpose To report our initial experience implementing a noncontrast-enhanced electrocardiograph (ECG) gated fast spin echo magnetic resonance angiography (MRA) technique for assessment of the calf arteries. Materials and Methods Noncontrast MRA images of 36 clinical patients examined over a 6-month period were evaluated by two radiologists for length and degree of stenosis of arterial segments. Diagnostic confidence in the technique was also recorded. The reference standard was a consensus reading by both radiologists using the noncontrast technique combined with two gadolinium-enhanced techniques: bolus-chase and time-resolved imaging. Results For stenosis evaluation the noncontrast technique demonstrated accuracy 79.4% (1083/1364), sensitivity 85.4% (437/512), and specificity 75.8% (646/852). The sequence demonstrated high negative predictive value (92.3%, 646/700). The technique had serious artifacts leading to poor diagnostic confidence in 17 patients (47.2%). These included motion (n = 7) and artifacts specific to the sequence, including inaccurate trigger delays (n = 5), linear artifact (n = 7), and vessel blurring (n = 5). When only patients in whom there was satisfactory diagnostic confidence were considered, accuracy, sensitivity, and negative predictive value were 92.2% (661/717), 92.4% (158/171), and 97.5% (503/516), respectively. Conclusion Our results indicate that when technically successful, noncontrast-enhanced MRA using ECG-gated fast spin echo can provide accurate imaging of the calf and pedal arteries. However, further development and optimization are needed to improve the robustness of the technique. J. Magn. Reson. Imaging 2008;28:181,189. © 2008 Wiley-Liss, Inc. [source] Superficial femoral artery occlusive disease severity correlates with MR cine phase-contrast flow measurementsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2006Kiyarash Mohajer MD Abstract Purpose To evaluate how cine phase-contrast (PC) flow data correlate with the severity of peripheral vascular disease (PVD). Materials and Methods Flow waveforms were obtained in 48 patients proximal and distal to superficial femoral artery (SFA) disease using the 2D cine PC technique with velocity encoding (venc) = 100 cm/second. Flow data were correlated with SFA disease severity and compared with data from nine healthy volunteers. Results Of 96 arterial segments in 48 patients, 26 were patent or only mildly stenotic, 35 had moderate-to-severe stenosis, and 35 were occluded. The flow patterns tended to become low-resistant below severe stenoses or occlusion. The mean peak flow velocity above/below SFA lesions was significantly higher in patients with severe disease (1.9 ± 1.0, P = 0.01) or occlusion (2.0 ± 1.0, P = 0.003) compared to normal volunteers (1.4 ± 0.6). The delay in peak velocity below the lesions showed a significant positive correlation with lesion severity (r = 0.65, P < 0.001). The mean flow volume ratio above/below SFA lesions was greater in patients with occluded vessels compared to normal volunteers (3.9 and 2.3 respectively; P = 0.04). Conclusion Cine PC flow waveform changes across atherosclerotic lesions correlate with disease severity. This may help determine which lesions are hemodynamically significant. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc. [source] Quiescent-interval single-shot unenhanced magnetic resonance angiography of peripheral vascular disease: Technical considerations and clinical feasibilityMAGNETIC RESONANCE IN MEDICINE, Issue 4 2010Robert R. Edelman Abstract We performed technical optimization followed by a pilot clinical study of quiescent-interval single-shot MR angiography for peripheral vascular disease. Quiescent-interval single-shot MR angiography acquires data using a modified electrocardiographic (ECG)-triggered, fat suppressed, two-dimensional, balanced steady-state, free precession pulse sequence incorporating slice-selective saturation and a quiescent interval for maximal enhancement of inflowing blood. Following optimization at 1.5 T, a pilot study was performed in patients with peripheral vascular disease, using contrast-enhanced MR angiography as the reference standard. The optimized sequence used a quiescent interval of 228 ms, ,/2 catalyzation of the steady-state magnetization, and center-to-out partial Fourier acquisition with parallel acceleration factor of 2. Spatial resolution was 2-3mm along the slice direction and 0.7-1mm in-plane before interpolation. Excluding stented arterial segments, the sensitivity, specificity, and positive and negative predictive values of quiescent-interval single-shot MR angiography for arterial narrowing greater than 50% or occlusion were 92.2%, 94.9%, 83.9%, and 97.7%, respectively. Quiescent-interval single-shot MR angiography provided robust depiction of normal peripheral arterial anatomy and peripheral vascular disease in less than 10 min, without the need to tailor the technique for individual patients. Moreover, the technique provides consistent image quality in the pelvic region despite the presence of respiratory and bowel motion. Magn Reson Med 63:951,958, 2010. © 2010 Wiley-Liss, Inc. [source] Tail arteries from chronically spinalized rats have potentiated responses to nerve stimulation in vitroTHE JOURNAL OF PHYSIOLOGY, Issue 2 2004Melanie Yeoh Patients with severe spinal cord lesions that damage descending autonomic pathways generally have low resting arterial pressure but bladder or colon distension or unheeded injuries may elicit a life-threatening hypertensive episode. Such episodes (known as autonomic dysreflexia) are thought to result from the loss of descending baroreflex inhibition and/or plasticity within the spinal cord. However, it is not clear whether changes in the periphery contribute to the exaggerated reflex vasoconstriction. The effects of spinal transection at T7,8 on nerve- and agonist-evoked contractions of the rat tail artery were investigated in vitro. Isometric contractions of arterial segments were recorded and responses of arteries from spinalized animals (,spinalized arteries') and age-matched and sham-operated controls were compared. Two and eight weeks after transection, nerve stimulation at 0.1,10 Hz produced contractions of greater force and duration in spinalized arteries. At both stages, the ,-adrenoceptor antagonists prazosin (10 nm) and idazoxan (0.1 ,m) produced less blockade of nerve-evoked contraction in spinalized arteries. Two weeks after transection, spinalized arteries were supersensitive to the ,1 -adrenoceptor agonist phenylephrine, and the ,2 -adrenoceptor agonist, clonidine, but 8 weeks after transection, spinalized arteries were supersensitive only to clonidine. Contractions of spinalized arteries elicited by 60 mm K+ were larger and decayed more slowly at both stages. These findings demonstrate that spinal transection markedly increases nerve-evoked contractions and this can, in part, be accounted for by increased reactivity of the vascular smooth muscle to vasoconstrictor agents. This hyper-reactivity may contribute to the genesis of autonomic dysreflexia in patients. [source] Magnetic resonance angiography in reversible cerebral vasoconstriction syndromesANNALS OF NEUROLOGY, Issue 5 2010Shih-Pin Chen MD Objective To investigate the evolution and clinical significance of vasoconstriction on magnetic resonance angiography (MRA) in patients with reversible cerebral vasoconstriction syndromes (RCVS). Methods Patients with RCVS were recruited and followed up with MRA examinations until normalization of vasoconstriction or for 6 months. The vasoconstriction severity of the major cerebral arterial segments (M1, M2, A1, A2, P1, P2, and basilar artery) was scored on a 5-point scale: 0 (0,<10%), 1 (10,<25%), 2 (25,<50%), 3 (50,<75%), and 4 (,75%). Subjects with at least 1 segment with a vasoconstriction score ,2 were eligible for the study. Initial mean scores of single or combined arterial segments were used to predict ischemic complications. Results Seventy-seven patients with RCVS (8 men/69 women; average age 47.7 ± 11.6 years) finished the study with a total of 225 MRAs performed. The mean number of arterial segments involved was 5.3 ± 3.0 in the initial MRA. Vasoconstriction scores reached their maximum 16.3 ± 10.2 days after headache onset, close to the average timing of headache resolution (16.7 ± 8.6 days). Vasoconstriction evolved in a parallel trend among different arterial segments. Seven (9.1%) patients developed posterior reversible encephalopathy syndromes (PRES). Six (7.8%) patients had ischemic stroke. A logistic regression model demonstrated that the M1,P2 combined score was associated with highest risk of PRES (odds ratio [OR], 11.6, p = 0.005) and ischemic stroke (OR, 3.4; p = 0.026). Interpretation MRA evaluation in patients with RCVS is valid. Vasoconstriction was pervasive and outlasted headache resolution. Vasoconstrictions in M1 and P2 are important determinants for PRES and ischemic stroke. ANN NEUROL 2010;67:648,656 [source] AT2 receptor-dependent vasodilation is mediated by activation of vascular kinin generation under flow conditionsBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2002Jun Katada Physiological roles of angiotensin II type 2 receptor (AT2) are not well defined. This study was designed to investigate the mechanisms of AT2 -dependent vascular relaxation by studying vasodilation in pressurized and perfused rat mesenteric arterial segments. Perfusion of angiotensin II in the presence of AT1 antagonist elicited vascular relaxation, which was completely dependent on AT2 receptors on endothelium. FR173657 (>1 ,M), a bradykinin (BK) B2 -specific antagonist, significantly suppressed AT2 -dependent vasodilation (maximum inhibition: 68.5% at 10 ,M). Kininogen-deficient Brown Norway Katholiek rats showed a significant reduction in AT2 -mediated vasodilatory response compared with normal wild-type Brown Norway rats. Indomethacin (>1 ,M), aprotinin (10 ,M) and soybean trypsin inhibitor (10 ,M) also reduced AT2 -dependent vasodilation. Our results demonstrated that stimulation of AT2 receptors caused a significant vasodilation through local production of BK in resistant arteries of rat mesentery in a flow-dependent manner. Such vasodilation counterbalances AT1 -dependent vasoconstriction to regulate the vascular tone. British Journal of Pharmacology (2002) 136, 484,491; doi:10.1038/sj.bjp.0704731 [source] Branches of the splenic artery and splenic arterial segmentsCLINICAL ANATOMY, Issue 5 2003A. Daisy Sahni Abstract In 200 adult autopsy specimens, the arterial supply to the pancreas and spleen was studied radiologically and by manual dissection. The splenic artery divided into two or three lobar arteries, which supplied its corresponding lobe; each lobar artery subsequently divided into two to four lobular branches. Six to twelve lobular branches were observed entering the splenic substance at the hilum. Lobar arteries did not anastomose with each other, hence, the lobes of the spleen are also termed segments. The lobules, however, were not found to be independent segments and the arteries of one lobule anastomosed with those of other lobules. The branching pattern of the splenic artery varied from one specimen to another, so much so that a prevailing pattern could not be identified. Polar arteries, particularly to the superior pole, arose quite proximal to the hilum in 51% of cases and were occasionally missed. In 45% of males and 40% of females, the posterior gastric artery arose from about the middle of the splenic artery. The splenic artery was not found to be tortuous in fetuses, newborns, and young children. Tortuosity was seen in only 10% of adults; thus, the characteristic tortuosity of the splenic artery appears to develop with age. Clin. Anat. 16:371,377, 2003. © 2003 Wiley-Liss, Inc. 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