case_images: PMC11814002_01
case_images: I Bedside scan conducted in the inpatient unit following the initiation of immune suppressive treatment. II Subsequent MRI follow-up utilizing both magnetic field strengths. The top row (A-C) displays T2-FLAIR images from HF-MRI (3 T), while the bottom row (D-F) showcases T2-FLAIR images from pULF-MRI, acquired during the initial scan after IS treatment initiation, and during inpatient/outpatient follow-ups. Minor changes without lesion progression were discernible using pULF-MRI, aligning with the findings from HF-MRI, particularly in the bilateral parieto-occipital regions (arrows). Note that a smaller satellite lesion in the left frontal area was also detectable using pULF-MRI (red arrowheads)
case_images: 415_2025_12938_Fig3_HTML.jpg
case_images: PMC11814002_01_415_2025_12938_Fig3_HTML.jpg
case_images: Fig3
case_images: Representative images showing a bedside scan in the inpatient room and PML lesions in both magnetic field strengths are shown in Fig. 3.
case_images: PMC11814002_02
case_images: Contrast enhancement and its resolution on follow up scan. 49-year-old man with PML and underlying HIV. Initial (panels A, B) and 3-month follow up (panels C, D) pULF-MRI acquired on the same day following HF-MRI are shown. Initial scans showing contrast enhancement on T1W images (yellow arrows; panel A) and extensive white matter lesion in the right cerebral hemisphere and left parietal lobe on T2-FLAIR images (red arrows; panel B) at both magnetic strength fields. On 3-month follow up, contrast enhancement areas are not visible on T1WI (yellow arrows; panel C), and lesion regression with ex vacuo enlargement of the nearby ventricle and sulci on T2-FLAIR (red arrows; panel D), are noted at both magnetic fields
case_images: 415_2025_12938_Fig2_HTML.jpg
case_images: PMC11814002_02_415_2025_12938_Fig2_HTML.jpg
case_images: Fig2
case_images: Follow-up scans in 1 and 3 months showed gradual resolution of the right hemisphere lesion and resolution of contrast enhancement, also visible on the same-day follow up pULF-MRI acquisitions (Fig. 2).
case_images: PMC11814002_03
case_images: pULF-MRI shows PML lesion progression and regression over time. 21-year-old man with PML and underlying primary immune deficiency. T2-FLAIR images acquired with pULF-MRI (64 miliTesla) (panel A) and HF-MRI (3 T) (panel B) are shown. pULF-MRI and HF-MRI were acquired within the same week in the initial scan, 1-month and 5-month follow up scans. PML lesion extending to the right deep gray matter area becomes more conspicuous in the 1-month follow up, and regression of this lesion is apparent on 5-month follow-up scans. These changes are visualized in both pULF-MRI and HF-MRI (yellow arrows, magnified view). Enlargement of the CSF spaces and Sylvian fissures (green arrows) suggesting parenchymal volume decrease is visualized on pULF-MRI during the follow-up. Arrows suggesting parenchymal volume decrease is visualized on pULF-MRI during the follow-up
case_images: 415_2025_12938_Fig4_HTML.jpg
case_images: PMC11814002_03_415_2025_12938_Fig4_HTML.jpg
case_images: Fig4
case_images: Follow-up HF-MRI after 5 months showed lesion regression in the left frontal area with the regression of the left deep gray matter lesion, reflected on the same-day pULF-MRI (both on T2-FLAIR) (Fig. 4).