Individual variability exists in parkinsonian motor symptoms despite a similar degree of nigrostriatal dopamine depletion in Parkinson’s disease (PD), called motor reserve. We enrolled 397 patients newly diagnosed with PD who underwent dual-phase ¹⁸F-FP-CIT PET upon initial assessment. Individual motor reserve was estimated based on initial parkinsonian motor symptoms and striatal dopamine transporter availability using a residual model. Patients with low motor reserve (the lowest quartile group, n = 100) exhibited decreased uptake in the occipital region compared to those with high motor reserve (the highest quartile group, n = 100) on early-phase ¹⁸F-FP-CIT PET images. Patients with high motor reserve had a lower risk of conversion to dementia than the those with low motor reserve, whereas the effect of PD groups on the risk of dementia conversion was not mediated by occipital hypoperfusion. These findings suggest that cerebral hypoperfusion in the occipital region is associated with low motor reserve in patients with PD.

Osteoradionecrosis of the chest wall after radiation therapy for breast cancer is rare; however, it is one of the most severe complications of radiation treatment. Radiologically, osteoradionecrosis can manifest as a focal lucent area in bone, periostitis, sclerosis, and cortical irregularity of bones on X-ray or computed tomography; therefore, differentiation from bone metastasis can be challenging. Associated insufficiency fractures, ulceration, and skin necrosis may also occur. We encountered a patient with osteoradionecrosis in the left anterior ribs after radiation therapy for breast cancer. Chest computed tomography revealed cortical irregularity with severe sclerotic changes of the anterior arc of the left fist to the fourth ribs. The patient's skin on the left chest wall exhibited ulceration with purulent discharge. Ultrasonography of the left chest wall revealed diffuse skin thickening with hyperechoic changes in the subcutaneous fat layer of the left chest wall with calcifications. The patient underwent rib resection and chest wall reconstruction. Recognizing characteristic imaging features of osteoradionecrosis is important for radiologists to differentiate it from bone metastasis and plan appropriate treatment.

Objective This study aims to investigate the clinical relevance of occipital hypoperfusion in patients with Parkinson’s disease (PD) with respect to clinical phenotype and the risk of dementia conversion.Methods We enrolled 349 patients with newly diagnosed PD and 48 healthy controls who underwent dual-phase 18F-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (18F-FP-CIT) positron emission tomography (PET). Patients with PD were classified into three groups based on posterior cortical perfusion patterns on early-phase 18F-FP-CIT PET images: PD with preserved posterior cortical perfusion (n=186), PD with parieto-temporal hypoperfusion (n=84), and PD with parieto-temporo-occipital hypoperfusion (n=79). Baseline clinical features and dementia conversion risk were compared across PD groups.Results Patients with preserved posterior cortical perfusion were younger than those in the other PD groups. Compared with the other groups, the parieto-temporo-occipital hypoperfusion group tended to have lower Cross-Cultural Smell Identification Test scores, a higher prevalence of rapid eye movement sleep behavior disorder, higher Unified PD Rating Scale motor scores, and more severe reductions in striatal dopamine transporter availability. The risk of dementia conversion was lower in patients with preserved posterior cortical perfusion than in those with posterior cortical hypoperfusion. However, the risk of dementia conversion did not differ between the parieto-temporal and parieto-temporo-occipital hypoperfusion groups.Conclusion Additional occipital hypoperfusion was not associated with an imminent risk of dementia conversion in patients with PD with posterior cortical hypoperfusion. Nonetheless, occipital involvement may serve as an indicator of the diffuse malignant subtype of PD.

Purpose: We aimed to investigate whether the patterns of striatal subregional dopamine loss and cerebral perfusion alterations differed between the 2 types of Parkinson’s disease (PD) (ie, brain-first and body-first PD) and had an impact on cognitive prognosis in PD. Patients and Methods: This retrospective study reviewed the data of newly diagnosed patients with PD who underwent dual-phase dopamine transporter (DAT) scans in tertiary medical centers. We classified the patients into 2 groups based on the rapid eye movement sleep behavior disorder (RBD) screening questionnaire: PD with RBD (body-first PD) and PD without RBD (brain-first PD) groups. Then, we investigated intergroup differences in subregional DAT availability, regional cerebral perfusion, and the rates of dementia conversion. Results: After adjusting for confounding variables, the body-first group exhibited lower DAT availability in the anterior putamen than the brain-first group (β=−0.10, SE=0.04, P=0.044). In comparative analyses of regional cerebral perfusion, the body-first group exhibited lower regional perfusion in the bilateral parieto-occipital area and left cerebellum than the brain-first group, and vice versa in the brainstem, left hippocampus, right pallidum, bilateral thalamus, and ventral diencephalon. The dementia conversion rate was significantly higher in the body-first group (HR=1.78, P=0.027) than in the brain-first group, which was largely mediated by DAT availability in the anterior putamen and parieto-occipital cerebral perfusion in mediation analyses. Conclusions: This study demonstrated that the patterns of striatal subregional dopamine depletion and regional cerebral perfusion differed between the brain-first and body-first PD subtypes, and these differences largely mediated inter-subtype differences in cognitive outcome.