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Fig 1. Enlargements of 3T transversal postcontrast fat-suppressed T1-weighted SE image of the superficial temporal arteries of 4 different patients representing typical images of each grade of the 4-point ranking scale. Temporal artery biopsy is negative in cases A and B, and suspected diagnosis of giant cell arteritis is validated by histology in cases C and D. The concomitant veins (arrowheads in A and C) display homogeneous signal intensity increase because of low venous flow. A, Mural thickness <0.5 mm and no mural enhancement; rating "0." Note the intraluminal signal intensity void (light arrow) because of arterial flow. B, Mural thickness <0.5 mm with only slight contrast enhancement (light arrow), probably because of enhancing vasa vasorum; rating "1." C, Mural thickening >0.6 mm and prominent mural enhancement (arrow); rating "2." D, Strong mural thickening >0.7 mm and strong mural enhancement (arrow); rating "3." The arterial lumen is still patent, as signal intensity void consistent with flow can be seen.
