T1-weighted hyperintensity in the Pulvinar: NOT Diagnostic of Fabry Disease Andrew C. McClelland and Alexander Mamourian Department of Radiology Perelman School of Medicine at the University of Pennsylvania Poster #: EE-11

Disclosures Andrew McClelland, MD, PhD: No disclosures Alexander Mamourian, MD: No disclosures

Purpose Fabry disease is lysosomal storage disease resulting from deficiency of hydrolase α-galactosidase A . CNS involvement can include early strokes with relatively nonspecific imaging findings secondary to large and small vessel ischemia. T1-weighted hyperintensity in the pulvinar nuclei of the thalamus has been reported as a characteristic imaging finding of Fabry Disease.

Purpose An axial T1-weighted image from the the report “T1 Hyperintensity in the Pulvinar: Key Imaging Feature for Fabry Disease”. Takanashi et al. AJNR (2003) 24(5):916.

Purpose However, there is accumulating evidence that multiple intravenous administrations of gadolinium can lead to intrinsic T1 shortening within regions of the brain that may persist long after injection. We present a case that demonstrates this effect and serves to illustrate the low specificity of intrinsic T1 shortening in the thalamus.

Case Report We report the brain imaging of a 48 year-old woman with medullary thyroid cancer. The patient had at least 28 prior MR scans with gadolinium injection in the preceding six years. These were mostly abdominal MR to evaluate liver metastasis progression as follows: 27 with gadobenate dimeglumine (cumulative dose of 108.4 g) Single administration of 1.8 g gadoxetate disodium. No history metabolic disorder such as Fabry disease, liver disease, or renal function impairment. There was no record of focal neurologic deficits. The brain MR was performed to to screen for intracranial metastatic disease.

T1-weighted axial image without intravenous contrast reveals bilateral symmetric T1 shortening in the pulvinar nuclei. Based on prior reports this could be mistaken for evidence of underlying Fabry disease.

T1- shortening also evident in the globus pallidi that could be mistaken for underlying liver disease.

More inferiorly, T1 shortening is also seen in the midbrain and cerebellar dentate nuclei.

Follow-up No signs of symptoms of Fabry disease appeared. The imaging findings are most likely due to the effects of multiple gadolinium contrast injections.

Summary The effects of accumulated contrast from enhanced MRI in the brain of patients who have regular imaging follow-up are commonly seen and can mimic other conditions such Fabry disease. We believe that since published reports about MR findings of Fabry’s disease pre-date awareness of this possibility, the literature on MR in cases of Fabry disease should be re-evaluated since it seems likely that these patients would have had multiple MR scans. Awareness of the appearance of retained Gd is essential to avoid misdiagnosis and unnecessary workup.

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