Validation of Highly Accelerated Wave–CAIPI SWI Compared with Conventional SWI and T2*-Weighted Gradient Recalled-Echo for Routine Clinical Brain MRI at 3T

J. Conklin; M.G.F. Longo; S.F. Cauley; K. Setsompop; R.G. González; P.W. Schaefer; J.E. Kirsch; O. Rapalino; S.Y. Huang

doi:10.3174/ajnr.A6295

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Fig 1.
Representative images comparing T2*W GRE and wave-SWI. A, Small hemorrhagic foci in the right temporal lobe are clearly seen on wave-SWI but are not well-visualized on T2*W GRE. These abnormalities fall within the radiation field of a treated right temporal lobe oligoastrocytoma and are presumed to reflect sequelae of radiation-induced vasculopathy. B, Multiple cerebral microhemorrhages in a 72-year-old man with history of cardiopulmonary bypass for aortic valve replacement and ascending aortic aneurysm repair, some of which are better seen on wave-SWI and some of which are seen only on wave-SWI (arrows). C, Hemorrhagic foci within a right anterior temporal lobe glioblastoma are clearly visualized on wave-SWI but obscured on T2*W GRE due to signal drop-out artifacts on the GRE sequence. D, Scattered foci of parenchymal (arrows) and subarachnoid (arrowheads) hemorrhage in the bilateral frontal lobes are better visualized on wave-SWI than T2*W GRE. E, Superficial hemosiderosis in the right frontoparietal region is better visualized on wave-SWI than T2*W GRE (arrows) in a patient with a history of multiple craniotomies for a recurrent anaplastic astrocytoma. F, Scattered foci of posterior predominant susceptibility effect are well-visualized on wave-SWI and not well-seen on T2*W GRE (box), in a 58-year-old man with remote radiation therapy to a posterior fossa atypical meningioma. The findings were presumed to reflect postradiation changes (microhemorrhages and/or small cavernous malformations).
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Fig 2.
Representative images comparing standard SWI and wave-SWI. A, Extensive susceptibility effect in the left temporal region in a 33-year-old woman with a history of trauma, corresponding to a combination of parenchymal contusion and subdural and subarachnoid hemorrhage. B, Focal subarachnoid hemorrhage in the left superior frontal sulcus (arrowheads). C, Scattered microhemorrhages throughout the bilateral basal ganglia in a patient with chronic poorly controlled hypertension. D, Incidental finding of a right occipital lobe developmental venous anomaly (arrows). E, Scattered foci of susceptibility effect in a patient with familial multiple cavernous malformations (arrows). F, Serpiginous foci of susceptibility effect in the left occipital region corresponding to an arteriovenous malformation (arrows), with associated rupture and extensive diffuse intraventricular hemorrhage (arrowheads). In all cases, visualization of the pathology was rated equivalent (score of 0, On-line Table 3) by both interpreting radiologists.
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Fig 3.
Balloonplot showing the results of the head-to-head comparison of T2*W GRE and wave-SWI. The size and color of each circle represent the percentage of cases that were assigned a given score, from a total of 85 cases with abnormal findings. The actual number of cases receiving a given score is indicated below each circle. Negative scores (left) favor T2*WI GRE, and positive scores (right) favor wave-SWI. The proportion of cases in which T2*W GRE was preferred over wave-SWI (P’) and the 95% confidence interval for this proportion are indicated at the right of the figure. The critical value (P_critical) is also provided, corresponding to the upper bound of the 95% confidence interval for P’. Superiority testing was performed as described in the Materials and Methods, and the corresponding P values are shown in the figure. Wave-SWI was superior to T2*W GRE for the 3 variables evaluated.
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Fig 4.
Balloonplot showing the results of the head-to-head comparison of standard SWI and wave-SWI. The size and the color of each circle represent the percentage of cases that were assigned a given score, from a total of 65 cases with abnormal findings. The actual number of cases receiving a given score is indicated below each circle. Negative scores (left) favor standard SWI, and positive scores (right) favor wave-SWI. The proportion of cases in which T2*WI GRE was preferred over wave-SWI (P’) and the 95% confidence interval for this proportion are indicated at the right of the figure. The critical value (P_critical) is also provided, corresponding to the upper bound of the 95% confidence interval for P’. Noninferiority testing was performed as described in the Materials and Methods, and the corresponding P values are shown in the figure. Wave-SWI was noninferior to standard SWI for the 3 variables evaluated.