Spectral presaturation with inversion recovery provides superior neuromelanin imaging for Parkinson's disease...

Neuromelanin-sensitive imaging visualizes degeneration of the substantia nigra pars compacta (SNc) and locus coeruleus (LC), characteristic features of Parkinson's disease (PD). Spectral presaturation with inversion recovery (SPIR), using fat-selective radiofrequency pulses, has been reported to provide superior delineation of the SNc and LC in healthy individuals and offers shorter acquisition times than conventional magnetization transfer (MT) imaging. This study evaluated the clinical utility of SPIR imaging for assessing PD compared with MT imaging.

Neuromelanin-sensitive images were acquired from 24 patients with PD and 24 healthy controls using MT and SPIR sequences, each with an acquisition time of approximately five minutes. Signal ratios (SRs) of the SNc and LC were automatically quantified using established brain atlases. For each sequence and brain region, diagnostic performance in distinguishing PD from controls was assessed using receiver operating characteristic curve analysis. In patients with PD, associations between SRs and nigrostriatal degeneration, as measured by dopamine transporter SPECT imaging, were investigated.

SPIR images yielded higher SRs in the SNc than MT images. Diagnostic accuracy for PD with SPIR imaging (87.50%) was significantly greater than that with MT imaging (77.08%). SRs of the SNc and LC on SPIR images were correlated with nigrostriatal degeneration on dopamine transporter SPECT, unlike MT images.

SPIR imaging demonstrated superior visualization of the SNc and LC, and outperformed MT imaging in the evaluation of PD. With shorter acquisition time and stronger correlation with nigrostriatal degeneration, SPIR represents a promising and practical tool for diagnosing and monitoring PD.