Magnetic Resonance Neurography Can Detect TTR-FAP Nerve Lesions, Study Reports
Magnetic resonance neurography can detect nerve lesions associated with the most common form of familial amyloid polyneuropathies, or FAPs, a study reports.
It dealt with lesions stemming from transthyretin familial amyloid polyneuropathy, also known as TTR-FAP. Magnetic resonance neurography, or MRN, is the direct imaging of nerves. It is a modification of magnetic resonance imaging.
The study, “Sural nerve injury in familial amyloid polyneuropathy: MR neurography vs clinicopathologic tools,” was published in the journal Neurology.
TTR-FAP is a fatal disease whose hallmark is an accumulation of abnormal fibrils — or tiny fibers —composed of misfolded transthyretin proteins, also known as TTRs.
The condition, most commonly caused by a TTR gene mutation, leads to nerve lesions.
“Early diagnosis of TTR-FAP is crucial because available causative treatment options fail to reverse existing damage to nerves and organs in this multisystem disorder,” researchers wrote.
Previous studies used MRN to detect lesions in the sciatic, tibial and peroneal nerves of people with transthyretin gene mutations who displayed no symptoms of the disease.
Researchers wanted to know if MRN could detect lesions in the small-caliber sural nerve (SN) of TTR-FAP patients and in people with TTR gene mutations but no symptoms of the disease.
The team enrolled 25 TTR-FAP patients, 10 people with a gene mutation but no symptoms, and 35 healthy age- and gender-matched individuals.
MRN analysis showed that TTR-FAP patients had the most lesions, followed by mutation carriers with no symptoms and healthy individuals.
MRN uses what’s known as a T2w signal to detect nerve lesions. The signal was stronger in TTR-FAP patients than in the other groups.
In addition, the mean cross-sectional area of SN lesions was larger in TTR-FAP patients and mutation carriers than in healthy individuals. The area was not significantly different between patients and mutation carriers, however.
Overall, the study showed that MRN is a reliable tool for distinguishing between TTR-FAP patients, people carrying the genetic basis of the disease but with no symptoms, and the general population.
“This study shows that high-resolution MRN can non-invasively detect and quantify peripheral nerve lesions in TTR-FAP even in the small-caliber SN and thus reasonably complements SN biopsy,” researchers wrote. “With its ability to give an inside view into nerve tissue integrity,” MRN could eventually help doctors monitor microstructural nerve alterations that occur during the course of the disease.