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Purpose: Nigrosome imaging using susceptibility-weighted imaging (SWI) and dopamine transporter imaging using 123 I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane ( 123 I-FP-CIT) single-photon emission computerized tomography (SPECT) can evaluate Parkinsonism. Nigral hyperintensity from nigrosome-1 and striatal dopamine transporter uptake are reduced in Parkinsonism; however, quantification is only possible with SPECT. Here, we aimed to develop a deep-learning-based regressor model that can predict striatal 123 I-FP-CIT uptake on nigrosome magnetic resonance imaging (MRI) as a biomarker for Parkinsonism., Methods: Between February 2017 and December 2018, participants who underwent 3 T brain MRI including SWI and 123 I-FP-CIT SPECT based on suspected Parkinsonism were included. Two neuroradiologists evaluated the nigral hyperintensity and annotated the centroids of nigrosome-1 structures. We used a convolutional neural network-based regression model to predict striatal specific binding ratios (SBRs) measured via SPECT using the cropped nigrosome images. The correlation between measured and predicted SBRs was evaluated., Results: We included 367 participants (203 women (55.3%); age, 69.0 ± 9.2 [range, 39-88] years). Random data from 293 participants (80%) were used for training. In the test set (74 participants [20%]), the measured and predicted 123 I-FP-CIT SBRs were significantly lower with the loss of nigral hyperintensity (2.31 ± 0.85 vs. 2.44 ± 0.90) than with intact nigral hyperintensity (4.16 ± 1.24 vs. 4.21 ± 1.35, P < 0.01). The sorted measured 123 I-FP-CIT SBRs and the corresponding predicted values were significantly and positively correlated (ρ c  = 0.7443; 95% confidence interval, 0.6216-0.8314; P < 0.01)., Conclusion: A deep learning-based regressor model effectively predicted striatal 123 I-FP-CIT SBRs based on nigrosome MRI with high correlation using manually-measured values, enabling nigrosome MRI as a biomarker for nigrostriatal dopaminergic degeneration in Parkinsonism., (© 2023. The Author(s).)

Objective: To evaluate the diagnostic performance of iron-sensitive sequences targeting the substantia nigra for distinguishing patients with Parkinson's disease from control participants and to identify factors causing heterogeneity., Methods: A systematic literature search in the Ovid-MEDLINE and EMBASE databases was performed for studies reporting the relevant topic before March 6, 2020. The pooled sensitivity and specificity values with their 95% confidence intervals were calculated using bivariate random-effects modeling. Subgroup and meta-regression analyses were also performed to determine factors influencing heterogeneity affecting the diagnostic performance among the clinical, MRI, and analytic characteristics., Results: A total of 22 articles including 1126 patients with Parkinson's disease and 933 control participants were enrolled in this systematic review and meta-analysis. Of those, 12 studies used objective analyses of quantitative susceptibility measurements, and 10 visually assessed the nigrosome-1 in subjective analyses. Iron-sensitive nigral magnetic resonance imaging showed a pooled sensitivity of 92% (95% confidence interval 88-95%) and a pooled specificity of 90% (95% confidence interval 81-95%). According to subgroup and meta-regression analyses, a longer mean disease duration in patients with Parkinson's disease (≥ 5 years), subjective analysis, a smaller size of pixel (< 0.6 mm 2 ), a larger flip angle (> 15°), a smaller slice thickness (≤ 1 mm), and specific targeting of the substantia nigra pars compacta improved the diagnostic performance., Conclusion: Iron-sensitive nigral magnetic resonance imaging had a favorable diagnostic performance in discriminating patients with Parkinson's disease from control participants. Subjective analytic methods remain superior to objective approaches. Further improvements of the spatial resolution and contrast-to-noise ratio to specifically target the nigrosome-1 with objective analytic methods will be needed., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Preoperative MRI detection of post-laminar optic nerve invasion (PLONI) offers guidance in assessing the probability of total tumor resection, an estimation of the extent of surgery, and screening of candidates for eye-preserving therapies or neoadjuvant chemotherapies in the patients with retinoblastoma (RB). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of MRI for detecting PLONI in patients with RB and to demonstrate the factors that may influence the diagnostic performance., Methods: Ovid-MEDLINE and EMBASE databases were searched up to January 11, 2020, for studies identifying the diagnostic performance of MRI for detecting PLONI in patients with RB. The pooled sensitivity and specificity of all studies were calculated followed by meta-regression analysis., Results: Twelve (1240 patients, 1255 enucleated globes) studies were included. The pooled sensitivity was 61%, and the pooled specificity was 88%. Higgins I 2 statistic demonstrated moderate heterogeneity in the sensitivity (I 2  = 72.23%) and specificity (I 2  = 78.11%). Spearman correlation coefficient indicated the presence of a threshold effect. In the meta-regression, higher magnetic field strength (3 T than 1.5 T), performing fat suppression, and thinner slice thickness (< 3 mm) were factors causing heterogeneity and enhancing diagnostic power across the included studies., Conclusions: MR imaging was demonstrated to have acceptable diagnostic performance in detecting PLONI in patients with RB. The variation in the magnetic field strength and protocols was the main factor behind the heterogeneity across the included studies. Therefore, there is room for developing and optimizing the MR protocols for patients with RB.

Purpose: Möbius syndrome is characterized by abducens and facial nerve palsy. However, the presence/absence of corresponding cranial nerves on MRI was not fully evaluated. The purpose of this study was to investigate the mechanism of Möbius syndrome by associating the presence of abducens and facial nerves on MR imagings with clinical features., Methods: We retrospectively reviewed the medical records and MR imagings of nine patients with Möbius syndrome between January 2004 and October 2015. The presence/absence of abducens and facial nerves on MR imaging, as well as corresponding neuro-ophthalmologic clinical features, was investigated., Results: Facial palsy was bilateral in six and unilateral in three patients. Abduction was limited bilaterally in five and unilaterally in four patients. The degrees of facial palsy and abduction limitation were variable, and asymmetric even in the bilateral cases. MR imaging documented bilateral absence of the abducens and facial nerves in six, absence of unilateral facial nerve and bilateral abducens nerves in one, and absence of facial and abducens nerves unilaterally on the same side in another. Both abducens and facial nerves were visualized bilaterally only in the one remaining patient., Conclusions: The absence of abducens and facial nerves on MR imaging was mostly correlated with the findings of facial palsy and abduction limitation in patients with Möbius syndrome. MR imaging aids in diagnosis of Möbius syndrome by documenting the absence or presence of abducens and facial nerves.

Aims: Our aim was to elucidate the etiology of Brown syndrome by evaluating the trochlea position, morphologic characteristics of the extraocular muscles including superior oblique muscle/tendon complex, and the presence of the cranial nerves (CN) III, IV, and VI using magnetic resonance imaging (MRI) in eight patients with unilateral congenital Brown syndrome and one patient with bilateral congenital Brown syndrome., Methods: Nine consecutive patients diagnosed with congenital Brown syndrome had a comprehensive ocular examination and MRI for the CN III, CN VI, and the extraocular muscles. Five of the nine patients underwent additional high resolution MRI for CN IV. The distance from the annulus of Zinn to the trochlea was measured., Results: Normal sized CN III, IV, and VI, as well as all extraocular muscles, could be identified bilaterally in all patients with available MRI. The distance from the annulus of Zinn to the trochlea was the same in both eyes., Conclusions: The findings for our patients, particularly in those who underwent additional high resolution MRI, did not provide evidence of a lack of CN IV as a cause of Brown syndrome.

Introduction: White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders., Methods: We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH), and we establish the I O -V WMH relationship., Results: Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners., Conclusions: The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency.