FIG 2.

Comparison of manual segmentation of cerebral T2 hyperintense lesions at four NAIMS sites. 3T MRI scans on Siemens scanners from a single subject with multiple sclerosis showing T2 hyperintense lesions from sagittal fluid-attenuated inversion recovery (FLAIR) sequences from 4 different North American Imaging in Multiple Sclerosis (NAIMS) sites and scanner models: Brigham and Women’s Hospital, Skyra; National Institutes of Health (NIH), Skyra; Oregon Health & Sciences University (OHSU), Trio; Cedars-Sinai, Verio. The upper panel shows the native images. The lower panel shows zoomed and cropped images to illustrate the key findings. The green arrow (lower panel) shows a possible lesion detected and traced on the NIH scan; the red arrow shows the same lesion not detected by the expert procedure on Brigham scan; the purple arrow shows a similar tubular area that was interpreted as a blood vessel on the Cedars-Sinai scan, which was not selected as a lesion by the expert tracing; no lesion was detected on the OHSU scan in this area on this slice or any of the adjacent slices (not shown). The blue arrow shows a different lesion detected and traced on the Brigham, NIH, and Cedars-Sinai scans but not detected by the expert review on the OHSU scan, appearing hazy/subtle (white arrow). The yellow arrow (upper panel) shows a lesion on all scans; however, when adding the tracing of all slices showing the lesion, the 3D volume of the lesion differed among sites: Brigham = 0.059 ml, NIH = 0.053 ml, OHSU = 0.033 ml, Cedars-Sinai = 0.053 ml.