Article Figures & Data
Figures
- Fig 1.
MR imaging protocol for AIS diagnosis.
- Fig 2.
Postprocessing sequences for the mMRA collateral map (left) and the MRP collateral map (right). After being loaded and stored in a 4D matrix of DICOM source images of DCE-MRA and DSC-MRP for approximately 1 minute, subtracted MIP images with both the time and spatial information are displayed. We apply ROIs on the MCA in nonischemic hemisphere and superior sagittal sinus. Arterial and venous signal intensity–time curves are generated by plotting signal changes in the ROIs, and 4 phases (arterial phase = from the beginning of arrival of the contrast in the MCA to the arterial bolus peak; capillary phase = from just past the arterial bolus peak to just before the venous bolus peak in the superior sagittal sinus; early venous phase = first half of the venous phase from the venous bolus peak to the starting point of the venous plateau; late venous phase = second half of the venous phase) of collateral maps are determined according to the signal intensity–time curves automatically. In mMRA collateral maps, an axial reformatting process for the original coronal images is added before generating the collateral map.
- Fig 3.
mMRA and MRP collateral maps at 2 hours 18 minutes and 2 hours 21 minutes after symptom onset in a 61-year-old woman with occlusion of the right MCA. The 3-month mRS score of the patient was 2. A, DCE-MRA shows occlusion of the right M1 MCA. Gray-scale (B) and color-coded (C) mMRA collateral maps. On the mMRA collateral maps, the collateral-perfusion delay involves more than one-half of the MCA territory, including the subcortical structures in the capillary phase and no collateral-perfusion delay in the early venous phase. The collateral score is 3 (intermediate to good). Gray-scale (D) and color-coded (E) MRP collateral maps. The MRP collateral map shows the same collateral score as the mMRA collateral map.
- Fig 4.
mMRA and MRP collateral maps at 5 hours 44 minutes and 5 hours 47 minutes after symptom onset in a 72-year-old man with occlusion of the left ICA and MCA. This patient died 27 days after admission. A, DCE-MRA shows occlusion of the left proximal ICA and MCA. Gray-scale (B) and color-coded (C) mMRA collateral maps. On the mMRA collateral maps, the collateral-perfusion delay involves more than one-half of the MCA territory, including the subcortical structures in the capillary phase, and persists until the late venous phase. The collateral score is 0 (very poor). Gray-scale (D) and color-coded (E) MRP collateral maps. The MRP collateral map shows the same collateral score as the mMRA collateral map.
- Fig 5.
Eight topographic regions of the MCA territory for MR collateral imaging (collateral map). I = insular ribbon; S = subcortical structures (basal ganglia and internal capsule); M1, M2, and M3 are the anterior, lateral, and posterior MCA territories, respectively, at the basal ganglia level; M4, M5, and M6 are the anterior, lateral, and posterior MCA territories, respectively, at the supraganglionic level.
- Fig 6.
A 100% stacked column chart of the functional outcomes and collateral grades of patients.
Tables
Parameter Acute Stroke MRI SS EPI-DWI SWI DCE-MRA (TWIST) DSC-MRP T2-FLAIR TR/TE (ms) 4800/71 28/20 2.62/0.95 1600/30 9000/95 TI (ms) 2500 Turbo factor 21 Flip angle 15° 21° 90° 150° Bandwidth (Hz/pixel) 1672 120 780 1446 206 Slice thickness/gap (mm) 5/2 2/0 1.2/0 5/2 5/2 FOV (mm) 240 × 240 240 × 195 400 × 300 240 × 240 240 × 217 Matrix size (mm) 130 × 130 384 × 156 320 × 182 128 × 128 256 × 174 B-value (s/mm2) 0, 1000 Measurements 1 1 30 60 1 GRAPPA 2 2 3 × 2 2 Temporal resolution (sec) 1.6 1.6 Dynamic reconstruction mode Forward share K-space sampling (center/periphery) (%) 15/20 Note:—SS indicates single-shot; TWIST, time-resolved imaging with stochastic trajectories; GRAPPA, generalized autocalibrating partially parallel acquisition.
Score Description of Collateral Status 5 (Excellent) No or smalla collateral-perfusion delay in the MCA territory in the capillary phase regardless of the collateral status in the arterial phase 4 (Good) Collateral-perfusion delay equal to or less than one-half of MCA territory in the capillary phase and no or small delay in the early venous phase 3 (Intermediate to good) 1) Collateral-perfusion delay equal to or less than one-half of the MCA territory in the capillary phase and equal or less than one-half in the early venous phase 2) Collateral-perfusion delay more than one-half of the MCA territory in the capillary phase and no or small delay in the early venous phase 2 (Intermediate to poor) Collateral-perfusion delay more than one-half of the MCA territory in the capillary phase and equal to or less than one-half in the early venous phase 1 (Poor) Collateral-perfusion delay more than one-half of the MCA territory in the early venous phase and equal to or less than one-half in the late venous phase 0 (Very poor) Collateral-perfusion delay/defect more than one-half of the MCA territory in the late venous phase regardless of perfusion status at previous phases ↵a “Small” indicates an area <1 of 8 MCA regions (Fig 5).
