Yunyan Zhang MD, PhD, Presenter: Nothing to Disclose

Luanne M. Metz, Abstract Co-Author: Nothing to Disclose

The fate of acute T1 hypointense lesions (acute black holes, ABHs) in multiple sclerosis (MS) is commonly determined by visual inspection in a followup scan. ABHs that persist (pABHs) suggest irreversible tissue damage whereas those that resolve (transient ABHs, tABHs) imply repair. Whether to increase tABH or inhibit pABH is used as a critical index to evaluate the potential of neuroprotective agents. However, following the evolution of ABHs is subjective; the real change in tissue structure is unknown. Prior data showed that MRI texture analysis, a measure of tissue regularity, is sensitive to differentiate tABHs and pABHs at onset. Our goal was to characterize texture changes in pABHs, tABHs, and chronic BHs (CBH) in comparison with in normal appearing white matter (NAWM).

Twenty MS patients were scanned at month 1, 3, 8 and 9. New enhancing ABHs were identified at month 1 or 3 (baseline), whose persistency were determined on the month 8 or 9 (followup) T1-weighted MRI. Non-enhancing BHs (CBHs), contralateral NAWM (contraNAWM) to each BH, and general NAWM in other parts of the brain were assessed simultaneously. Regions of interest (ROIs) were chosen at baseline and matched on the co-registered followup MRI. Pixel-wise, multi-resolution MRI texture was calculated for each ROI. Standard error of measurement (SEM) and changing threshold in texture were calculated in NAWM.

There were 15 ABHs (8 pABH; 7 tABH) and 10 CBH identified in 9 patients. The range of SEM and resulted threshold over 8 months was 1.5-0.2 and 4.0-0.8 from coarse to fine texture in the general NAWM; 0.9-0.4 and 2.4-1.1 in the contraNAWM to pABH, 2.9-0.5 and 7.9-1.4 to tABH, and 1.6-0.4 and 3.2-1.0 to CBH over 5-8 months. The change in texture either in pABHs or tABHs was within the SEM or threshold of the NAWM.

MS is a complex disease characterized both by multifocal pathology and diffuse NAWM abnormality. Short period evolution of ABHs may reflect a change in structure that is similar to that occurred in the occult NAWM, or simply within the SEM. Thus, the count of tABH may not represent completely tissue repair.

Quantitative assessment of ABHs or followup over a longer period than the typical 5-8 months may be a more precise way to monitor disease evolution or the efficacy of neuroprotective treatments.

Zhang, Y, Metz, L, Evolution of T1 ‘Black Holes’ in Multiple Sclerosis: Has Tissue Structure Actually Changed?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016866.html