Comparison of susceptibility-weighted imaging and susceptibility map-weighted imaging for the diagnosis of Parkinsonism with nigral hyperintensity

Abstract

To determine whether susceptibility map-weighted imaging (SMWI) was superior to conventional susceptibility-weighted imaging (SWI) in the diagnosis of Parkinson's disease (PD) and in its correlation with 123 I-2bcarbomethoxy-3b-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane single photon emission computerized tomography ( 123 I-FP-CIT SPECT). Methods: Between May 2017 and February 2018, 125 consecutive patients diagnosed with idiopathic PD, vascular pseudoparkinsonism, essential tremor, or drug-induced parkinsonism and who underwent 123 I-FP-CIT SPECT imaging and 3 T SWI on the same day or within 3 months were included in this retrospective study. In all patients, SMWI images were generated from SWI images. On both MRIs, two neuroradiologists independently evaluated the status of nigral hyperintensity on each side of substantia nigra. Inter-observer agreements for the nigral hyperintensity were tested. Using consensus reading, concordance between SWI, SMWI, and 123 I-FP-CIT SPECT were evaluated, and the diagnostic performance between SWI and SMWI for PD was compared. Results: Inter-observer agreement for the nigral hyperintensity was higher for SMWI (right, κ = 0.919; left, κ = 0.984) than for SWI (right, κ = 0.918; left, κ = 0.902). SMWI (right 67.2 %, left 68.0 %) showed a higher concordance rate with the results of 123 I-FP-CIT SPECT than SWI (right 60.0 %, left 59.2 %). SMWI (area under curve [AUC], 0.791) provided significantly higher diagnostic performance for PD than SWI (AUC, 0.720; P = 0.0005). Conclusion: SMWI may be a superior assessment tool for nigral hyperintensity than SWI and may be an improved diagnostic imaging modality for patients with suspected PD.

Dorsolateral Nigral Hyperintensity on 1.5 T Versus 3 T Susceptibility‐Weighted Magnetic Resonance Imaging in Neurodegenerative Parkinsonism

“…A direct comparison of SMWI to standard SWI in the assessment of DNH resulted in a superiority of SMWI in terms of a higher interobserver agreement, a higher concordance rate with 123 I‐FP‐CIT SPECT and a higher diagnostic performance for PD 17 . Therefore, our results and the findings of previous studies using more advanced SWI techniques 16–19 emphasize the importance of appropriate technical standards to ensure a sufficient diagnostic accuracy of DNH in neurodegenerative parkinsonism. Particularly important in imaging the SN are a sufficient spatial resolution, the slice thickness and the signal‐to‐noise‐ratio (SNR) 20 .…”

“…Notably, more advanced techniques like susceptibility‐map weighted imaging (SMWI), which can be generated from the SWI protocol by combining a magnitude image with a quantitative susceptibility mapping (QSM)‐based weighting factor, 15,16 were investigated to enhance the visibility of DNH by improving the contrast‐to‐noise ratio (CNR) 16 . A direct comparison of SMWI to standard SWI in the assessment of DNH resulted in a superiority of SMWI in terms of a higher interobserver agreement, a higher concordance rate with 123 I‐FP‐CIT SPECT and a higher diagnostic performance for PD 17 . Therefore, our results and the findings of previous studies using more advanced SWI techniques 16–19 emphasize the importance of appropriate technical standards to ensure a sufficient diagnostic accuracy of DNH in neurodegenerative parkinsonism.…”

Imaging modalities in differential diagnosis of Parkinson’s disease: opportunities and challenges

“…SWI sequences were considered to have a stronger and more accurate correlation with brain iron load than R 2 relaxation rate alone [38]. Studies have shown that this sequence is severely sensitive to mineralization and substances with magnetic susceptibility, hence, to be more sensitive than conventional gradient echo sequence in the detection of PD and parkinsonian syndromes [41,42].…”

Comparative Performance of Susceptibility Map-Weighted MRI According to the Acquisition Planes in the Diagnosis of Neurodegenerative Parkinsonism

“…Several studies have suggested that the loss of dorsolateral nigral hyperintensity on susceptibility-weighted imaging (SWI) (i.e., loss of the swallowtail appearance) indicates nigrostriatal dopaminergic degeneration and can thus be used as an imaging biomarker for IPD [ 3 4 5 6 7 ]. Furthermore, the visibility of the nigrosome 1 on MRI has been improved with “susceptibility map-weighted imaging (SMwI),” which resolves the blooming artifacts of SWI and improves the contrast-to-noise and signal-to-noise ratio [ 8 9 10 11 ] over SWI.…”

“…Prior studies have shown the high diagnostic performances of both SWI and SMwI in determining the nigral hyperintensity in the substantia nigra [ 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ]. However, these studies used heterogeneous study populations and imaging protocols, and discretionally chose different types of MR acquisition planes.…”