MRA versus digital subtraction angiography in acute subarachnoid haemorrhage: a blinded multireader study of prospectively recruited patients

Abstract

We performed a blinded multireader study comparing MR angiography (MRA) with digital subtraction angiography (DSA) in 34 prospectively recruited patients who presented with acute subarachnoid haemorrhage (SAH). Two observers independently reviewed the MRA and DSA studies some months after clinical presentation. Presence of an aneurysm was rated on a 4-point confidence scale. Cases in which the initial interpretation of the observers varied were jointly reviewed to reach a consensus opinion. DSA was deliberately chosen not to represent the reference standard and the clinical course and surgical findings were used to explain significant differences between the consensus readings of MRA and DSA. Diagnostic confidence and interobserver agreement were, overall, higher on DSA than on MRA studies (kappa DSA = 0.64 versus kappa MRA = 0.52 with 95% CI for delta = kappa DSA-kappa MRA [-0.06, 0.31]). With both methods, discrepancies between observers were due to aneurysms overlooked rather than false-positive readings by one observer. Diagnostic accuracy therefore improved when the readings of the two observers were combined, particularly for MRA. Intermethod agreement was only fair and similar for both readers (kappa reader 1 = 0.37 versus kappa reader 2 = 0.32 with 95% CI for delta = kappa reader 1-kappa reader 2 [-0.02, 0.11]). Both interobserver and intermethod agreements improved when the data were analysed on a per-study (positive or negative study) rather than on a per-aneurysm basis. Differences in the consensus reading were due to five aneurysms (four single and one multiple) detected only with MRA and five (two single and three multiple) detected only with DSA. MRA and DSA should be regarded as complementary in the investigation of patients with acute SAH. DSA can no longer be regarded as the reference standard.

Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage

“…Another small prospective study suggested that digital subtraction angiography and MRA were complementary. 110 However, in a review of the available literature, Wardlaw and White 111 concluded that "quality of data testing their [MRA and CTA] accuracy is limited." Thus, until better data become available, the appropriate technique for initial screening should be individualized; however, when it is clinically imperative to know if an aneurysm exists, catheter angiography remains the gold standard.…”

Computer-Assisted Detection of Cerebral Aneurysms in MR Angiography in a Routine Image-Reading Environment: Effects on Diagnosis by Radiologists

“…The limitations of MRA compared with DSA include the limited spatial resolution and artifacts such as motion, susceptibility, and flow. 2 Nevertheless, an increasing number of recent studies suggest that DSA is no longer considered essential for establishing the diagnosis of cerebral aneurysms, 3,4 particularly when 3T MR imaging scanners are used. 2,5,6 Despite the continuing sophistication of the imaging technique, 1 important cause of the limited sensitivity of MRA is the detection failures of radiologists.…”

Diagnosing Intracranial Aneurysms With MR Angiography

“…32 This large heterogeneity in sensitivity and specificity estimates was also observed in this review, and subgroup analyses were performed in an attempt to identify potential sources of variation in study results. Three studies (Jäger et al, 17 Kouskouras et al, 18 and White et al 24 ) produced outliers in terms of sensitivity or specificity. Two of these used analog image evaluation.…”

“…Two of these used analog image evaluation. 17,24 After excluding the studies by Jäger and White that evaluated images on hard copy films, diagnostic performance increased and heterogeneity decreased. Five of the 7 missed aneurysms >5 mm came from these 2 studies.…”

“…[26][27][28][29][30][31] In total, 12 articles were included in the meta-analysis. [14][15][16][17][18][19][20][21][22][23][24][25] The study characteristics are shown in Table 1. All included studies had a consecutive design and used DSA as the reference standard.…”