Diagnostic Accuracy of Neuromelanin Sensitive MRI in Parkinsonian Disorders: A Systematic Review and Meta-analysis
ELISA FERREIRA1, Claudia Figueredo Nascimento Salomão Santos2, Iago Vinicius Maia Hezel3, Filipe Ramos Barra, Maria Clara Merighi4, Gustavo Regus Schuster5, Rodrigo dos Reis Schevz6, Bernard Giancristoforo Campos7
1Diagnóstica Exames de Imagem, 2UNIFIG, 3Federal University of Pernambuco, 4State University of Londrina, 5Federal University of Santa Maria, 6FMABC, 7RIVOA
Objective:
This meta-analysis aimed to evaluate diagnostic accuracy of Neuromelanin-sensitive MRI (NM-MRI) in distinguishing Parkinson’s disease (PD) and related syndromes from healthy controls.
Background:
PD remains difficult to diagnose, with misdiagnosis rates of up to 25% due to symptom overlap and the absence of validated biomarkers. NM-MRI enables in vivo assessment of neuromelanin in the substantia nigra and locus coeruleus, where signal loss reflects dopaminergic neurodegeneration.
Design/Methods:
We searched PubMed, Embase, and Cochrane databases from inception to February 2025 for studies assessing the diagnostic accuracy of NM-MRI for patients with PD. Primary diagnostic accuracy measure was defined as the best-balanced sensitivity and specificity reported in each study. Subgroup analyses were conducted to evaluate diagnostic accuracy of NM-MRI in specific target regions, such as substantia nigra and locus coeruleus, according to each imaging parameter such as volume and signal intensity metrics. All statistical analyses were performed using R software, version 4.5.1.
Results:
28 studies comprising 2,268 patients were included. NM-MRI showed high diagnostic accuracy for differentiating PD from healthy controls, with pooled sensitivity and specificity of 88.0% and 84.4%, respectively. Subgroup analyses indicated that volumetric and areal assessments of the substantia nigra were highly accurate, with an area under the curve (AUC) of 0.869 and 0.857, respectively. Signal intensity performed less effectively, with an AUC of 0.848. Subjective approaches yielded the highest sensitivity (90.8%).
Conclusions:
NM-MRI demonstrates high overall diagnostic accuracy in differentiating PD from healthy controls, with pooled sensitivity of 88% and specificity of 84%. Among evaluated parameters, volumetric and areal analyses of the substantia nigra proved robust, while subjective approaches yielded the highest sensitivity but with limited reproducibility.
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