U-King-Im J M, Trivedi R A, Graves M J, Higgins N J, Cross J J, Tom B D, Hollingworth W, Eales H, Warburton E A, Kirkpatrick P J, Antoun N M, Gillard J H
University Department of Radiology, Addenbrooke's Hospital, Cambridge, UK.
Neurology. 2004 Apr 27;62(8):1282-90. doi: 10.1212/01.wnl.0000123697.89371.8d.
To compare contrast-enhanced MR angiography (CEMRA) with intra-arterial digital subtraction angiography (DSA) for evaluating carotid stenosis.
A total of 167 consecutive symptomatic patients, scheduled for DSA following screening duplex ultrasound (DUS), were prospectively recruited to have CEMRA. Three independent readers reported on each examination in a blinded and random manner. Agreement was assessed using the Bland-Altman method. Diagnostic and potential clinical impact of CEMRA was evaluated, singly and in combination with DUS.
CEMRA tended to overestimate stenosis by a mean bias ranging from 2.4 to 3.8%. A significant part of the disagreement between CEMRA and DSA was directly caused by interobserver variability. For detection of severe stenosis, CEMRA alone had a sensitivity of 93.0% and specificity of 80.6%, with a diagnostic misclassification rate of 15.0% (n = 30). More importantly, clinical decision-making would, however, have been potentially altered only in 6.0% of cases (n = 12). The combination of concordant DUS and CEMRA reduced diagnostic misclassification rate to 10.1% (n = 19) at the expense of 47 (24.9%) discordant cases needing to proceed to DSA. An intermediate approach of selective DUS review resulted in a marginally worse diagnostic misclassification rate of 11.6% (n = 22) but with only 6.8% of discordant cases (n = 13).
DSA remains the gold standard for carotid imaging. The clinical misclassification rate with CEMRA, however, is acceptably low to support its safe use instead of DSA. The appropriateness of combination strategies depends on institutional choice and cost-effectiveness issues.
比较对比增强磁共振血管造影（CEMRA）与动脉内数字减影血管造影（DSA）在评估颈动脉狭窄方面的效果。
共有167例连续的有症状患者，在经筛查性双功超声（DUS）检查后计划进行DSA检查，前瞻性地招募他们进行CEMRA检查。三名独立的阅片者以盲法和随机方式对每次检查进行报告。使用Bland-Altman方法评估一致性。单独以及联合DUS评估CEMRA的诊断和潜在临床影响。
CEMRA倾向于高估狭窄程度，平均偏差范围为2.4%至3.8%。CEMRA与DSA之间的显著差异部分直接由观察者间的变异性引起。对于严重狭窄的检测，单独使用CEMRA时，敏感性为93.0%，特异性为80.6%，诊断错误分类率为15.0%（n = 30）。然而，更重要的是，临床决策可能仅在6.0%的病例（n = 12）中发生改变。一致的DUS和CEMRA联合使用将诊断错误分类率降低至10.1%（n = 19），代价是47例（24.9%）不一致的病例需要进行DSA检查。一种选择性DUS复查的中间方法导致诊断错误分类率略高至（n = 22），但不一致的病例仅占6.8%（n = 13）。
DSA仍然是颈动脉成像的金标准。然而，CEMRA的临床错误分类率低至可接受程度，以支持其安全替代DSA使用。联合策略的适用性取决于机构选择和成本效益问题。
