A multiple-tissue-specific magnetic resonance imaging model for diagnosing Parkinson's disease: a brain radiomics study.

Brain radiomics can reflect the characteristics of brain pathophysiology. However, the value of T1-weighted images, quantitative susceptibility mapping, and R2* mapping in the diagnosis of Parkinson's disease (PD) was underestimated in previous studies. In this prospective study to establish a model for PD diagnosis based on brain imaging information, we collected high-resolution T1-weighted images, R2* mapping, and quantitative susceptibility imaging data from 171 patients with PD and 179 healthy controls recruited from August 2014 to August 2019. According to the inclusion time, 123 PD patients and 121 healthy controls were assigned to train the diagnostic model, while the remaining 106 subjects were assigned to the external validation dataset. We extracted 1408 radiomics features, and then used data-driven feature selection to identify informative features that were significant for discriminating patients with PD from normal controls on the training dataset. The informative features so identified were then used to construct a diagnostic model for PD. The constructed model contained 36 informative radiomics features, mainly representing abnormal subcortical iron distribution (especially in the substantia nigra), structural disorganization (e.g., in the inferior temporal, paracentral, precuneus, insula, and precentral gyri), and texture misalignment in the subcortical nuclei (e.g., caudate, globus pallidus, and thalamus). The predictive accuracy of the established model was 81.1 ± 8.0% in the training dataset. On the external validation dataset, the established model showed predictive accuracy of 78.5 ± 2.1%. In the tests of identifying early and drug-naïve PD patients from healthy controls, the accuracies of the model constructed on the same 36 informative features were 80.3 ± 7.1% and 79.1 ± 6.5%, respectively, while the accuracies were 80.4 ± 6.3% and 82.9 ± 5.8% for diagnosing middle-to-late PD and those receiving drug management, respectively. The accuracies for predicting tremor-dominant and non-tremor-dominant PD were 79.8 ± 6.9% and 79.1 ± 6.5%, respectively. In conclusion, the multiple-tissue-specific brain radiomics model constructed from magnetic resonance imaging has the ability to discriminate PD and exhibits the advantages for improving PD diagnosis.

Progressive brain atrophy in Parkinson's disease patients who convert to mild cognitive impairment.

AIMS: Cognitive impairment is a common symptom in the trajectory of Parkinson's disease (PD). However, the pathological underpinning is not fully known. We aimed to explore the critical structural alterations in the process of cognitive decline and its relationships with the dopaminergic deficit and the level of related cerebrospinal fluid (CSF) proteins. METHODS: Ninety-four patients with PD and 32 controls were included in this study. Neuropsychological tests were performed at baseline and after 28 months to identify which patients had normal cognition and which ones developed PD-MCI after follow-up ("converters"). Gray matter atrophy was assessed in cross-sectional and longitudinal analyses, respectively. The associations between altered GMV with dopamine transporter (DAT) results and the level of CSF proteins were assessed. RESULTS: Among the 94 patients with normal cognition at baseline, 24 (mean age, 63.1 years) developed PD-MCI after 28 months of follow-up, and 70 (mean age, 62.3 years) remained nonconverters. The converters showed significant right temporal atrophy at baseline and extensive atrophy in temporal lobe at follow-up. Progressive bilateral frontal lobe atrophy was found in the converters. Baseline right temporal atrophy was correlated with the striatal dopaminergic degeneration in the converters. No correlation was found between the right temporal atrophy and the alterations of CSF proteins. CONCLUSION: Early atrophy in temporal lobes and progressive atrophy in frontal lobes might be a biomarker for developing multidomain impairment of cognition and converting to PD-MCI. Furthermore, cognition-related temporal atrophy might be associated with dopaminergic deficit reflected by DAT scan but independent of CSF proteins in patients with PD who convert to PD-MCI.

Radiological and clinical findings of osseous peripheral primitive neuroectodermal tumors.

Peripheral primitive neuroectodermal tumor (pPNET) is a rare and highly malignant undifferentiated type of tumor. The aim of the present study was to analyze the computed tomography (CT), magnetic resonance imaging (MRI) and clinical findings of osseous pPNET. The present study retrospectively analyzed the clinical data and CT findings from 15 patients with osseous pPNET; the MRI findings from 11 of these 15 patients were confirmed by histopathological examination. The 15 patients included 9 men and 6 women. The mean patient age was 29 years (range, 16-64 years) and 11 cases were aged <30 years. A CT scan was performed in 15 cases and the findings included a lytic lesion (13 cases), a lytic lesion with irregular sclerosis and dilation (2 cases), a soft tissue mass (15 cases), calcification (2 cases) and periosteal reaction (5 cases). A total of 9 cases of soft tissue mass were heterogeneous, with different sizes of lower-density necrotic areas. An enhanced MRI scan was performed in 11 cases. On T1-weighted images (WI), the soft tissue mass was isointense (8 cases) and marginally hyperintense (3 cases). On T2WI, aggressive soft tissue masses were heterogeneous iso- or hyperintense (11 cases). On contrast-enhanced T1WI, marked heterogeneous enhancement was present in 10 cases and intermediate heterogeneous enhancement in 1 case. The results indicated that osseous pPNET mainly affects male adolescents and young adults. The CT findings of osseous pPNET were destructive lesions with a soft tissue mass and, occasionally, with periosteal reaction. The tumor was often isodense, with patchy hypodense areas. Tumor calcification was uncommon. The MRI findings were those of an aggressive soft tissue mass exhibiting isointensity on T1WI and iso- or hyperintensity on T2WI, with marked heterogeneous enhancement. Although the imaging characteristics of pPNETs may be non-specific, CT and MRI may be useful in delineating the extent of the tumor, identifying distant metastases, predicting resectability and monitoring treatment.

Rare presentation of peripheral primitive neuroectodermal tumor in the maxilla and mandible: A report of two cases.

Peripheral primitive neuroectodermal tumor (pPNET) is a rare and highly malignant undifferentiated tumor, which presents in infants and young adults. pPNETs in the head and neck region are uncommon and have a varying incidence of occurrence. Peripheral PNETs of the maxilla and mandible are particularly rare. At present, only 16 cases of pPNET of the maxilla and 13 cases of pPNET of the mandible have been reported. The present study describes a case of pPNET of the maxilla in a 16-year-old male and a case of pPNET of the mandible in another 16-year-old male. The present study reports the radiological findings and the clinical courses of the two patients.