Progressive depletion of midbrain dopamine neurons (PDD) is associated with deficits in the initiation, speed, and fluidity of voluntary movement. Models of basal ganglia function focus on initiation ...deficits; however, it is unclear how they account for deficits in the speed or amplitude of movement (vigor). Using an effort-based operant conditioning task for head-fixed mice, we discovered distinct functional classes of neurons in the dorsal striatum that represent movement vigor. Mice with PDD exhibited a progressive reduction in vigor, along with a selective impairment of its neural representation in striatum. Restoration of dopaminergic tone with a synthetic precursor ameliorated deficits in movement vigor and its neural representation, while suppression of striatal activity during movement was sufficient to reduce vigor. Thus, dopaminergic input to the dorsal striatum is indispensable for the emergence of striatal activity that mediates adaptive changes in movement vigor. These results suggest refined intervention strategies for Parkinson’s disease.
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•A mouse model of Parkinson’s disease produces a persistent reduction in effort•The neural representation of movement vigor in striatum requires dopamine•Acute suppression of striatal activity during execution enervates movement•Dopamine repletion is sufficient to restore striatal activity and invigorate movement
Movement vigor, reduced in Parkinson’s disease, is regulated by dopamine-dependent activity in the striatum.
Male breast cancer is a rare entity consisting of less than 1% of all breast cancer diagnoses, in which pure ductal carcinoma in situ (DCIS) without an invasive component accounts for approximately ...10% of these diagnoses. Early diagnosis and appropriate management are essential to ensure favorable outcomes. We present a rare case of mammographically and sonographically occult pure DCIS in a male patient presenting with unilateral bloody nipple discharge, highlighting imaging features and the potential utility of breast MRI that aided diagnosis and management.
Cowden syndrome is a rare autosomal dominant genetic disorder characterized by a germline mutation in the phosphatase and tensin homolog gene, leading to multiple hamartomas, neurodevelopmental ...disorders, and an increased lifetime risk of multiple cancers. Malignancy is the most common cause of mortality in Cowden syndrome, with breast cancer being the most common malignancy encountered in females with the disorder. Screening guidelines for this population should address this risk at an early age. We present a case of metachronous thyroid cancer followed by synchronous breast cancer and melanoma in a young female with Cowden syndrome, highlighting diagnostic imaging, management, and screening considerations.
Annual breast magnetic resonance imaging (MRI) is recommended to screen high-risk populations for breast cancer, although costs are significant. This study assesses the performance of an abbreviated ...MRI protocol as a resource-efficient approach for screening patients at high-risk of breast cancer, and assesses whether the abbreviated protocol alters the assigned Breast Imaging Reporting and Data System (BI-RADS) category.
This is a prospective paired cohort study performed in an academic ambulatory setting. MRI images of women at high risk of breast cancer were reviewed using an abbreviated MRI protocol, followed by an immediate review of additional sequences included in a full diagnostic protocol. BI-RADS assessments, including all changes and interpretation times, were recorded for both the abbreviated and full protocol reviews. Cancer detection rate, positive predictive value 3 (PPV3), sensitivity, and specificity were calculated.
A total of 1052 MRI cases were reviewed. The cancer detection rate was 13.3 per 1000 with a PPV3 of 30.4% based on the full protocol. Review of sequences included in the full protocol resulted in a change in the final BI-RADS assessments in 3.4% of the cases, the majority of which did not change clinical management with respect to biopsy. The sensitivity and specificity of the abbreviated and full protocols were not significantly different.
This pilot study of an abbreviated MRI protocol demonstrates effective performance in cancer detection. BI-RADS assessments were rarely altered with the additional information afforded by the full protocol. The abbreviated protocol holds promise for resource-efficient breast cancer screening in high-risk women.
Invasive lobular carcinoma (ILC) in the male breast is a rare subtype of a rare disease in men, accounting for approximately 1%-2% of all male breast cancers 1,2. Only a few cases have been reported ...in the literature. The pathophysiology is uncommon due to a paucity of lobular development seen in men. We present a rare case of ILC in the male breast, highlighting imaging, pathology findings, and clinical management.
Background Digital breast tomosynthesis (DBT) has higher diagnostic accuracy than digital mammography, but interpretation time is substantially longer. Artificial intelligence (AI) could improve ...reading efficiency. Purpose To evaluate the use of AI to reduce workload by filtering out normal DBT screens. Materials and Methods The retrospective study included 13 306 DBT examinations from 9919 women performed between June 2013 and November 2018 from two health care networks. The cohort was split into training, validation, and test sets (3948, 1661, and 4310 women, respectively). A workflow was simulated in which the AI model classified cancer-free examinations that could be dismissed from the screening worklist and used the original radiologists' interpretations on the rest of the worklist examinations. The AI system was also evaluated with a reader study of five breast radiologists reading the DBT mammograms of 205 women. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and recall rate were evaluated in both studies. Statistics were computed across 10 000 bootstrap samples to assess 95% CIs, noninferiority, and superiority tests. Results The model was tested on 4310 screened women (mean age, 60 years ± 11 standard deviation; 5182 DBT examinations). Compared with the radiologists' performance (417 of 459 detected cancers 90.8%, 477 recalls in 5182 examinations 9.2%), the use of AI to automatically filter out cases would result in 39.6% less workload, noninferior sensitivity (413 of 459 detected cancers; 90.0%;
= .002), and 25% lower recall rate (358 recalls in 5182 examinations; 6.9%;
= .002). In the reader study, AUC was higher in the standalone AI compared with the mean reader (0.84 vs 0.81;
= .002). Conclusion The artificial intelligence model was able to identify normal digital breast tomosynthesis screening examinations, which decreased the number of examinations that required radiologist interpretation in a simulated clinical workflow. Published under a CC BY 4.0 license.
See also the editorial by Philpotts in this issue.
Purpose
This study assessed the upgrade rates of high-risk lesions (HRLs) in the breast diagnosed by MRI-guided core biopsy and evaluated imaging and clinical features associated with upgrade to ...malignancy.
Methods
This IRB-approved, retrospective study included MRI-guided breast biopsy exams yielding HRLs from August 1, 2011, to August 31, 2020. HRLs included atypical ductal hyperplasia (ADH), lobular carcinoma in situ (LCIS), atypical lobular hyperplasia (ALH), radial scar, and papilloma. Only lesions that underwent excision or at least 2 years of MRI imaging follow-up were included. For each HRL, patient history, imaging features, and outcomes were recorded.
Results
Seventy-two lesions in 65 patients were included in the study, with 8/72 (11.1%) of the lesions upgraded to malignancy. Upgrade rates were 16.7% (2/12) for ADH, 100% (1/1) for pleomorphic LCIS, 40% (2/5) for other LCIS, 0% (0/19) for ALH, 0% (0/18) for papilloma, and 0% (0/7) for radial scar/complex sclerosing lesion. Additionally, two cases of marked ADH bordering on DCIS and one case of marked ALH bordering on LCIS, were upgraded. Lesions were more likely to be upgraded if they presented as T2 hypointense (versus isotense, OR 6.46, 95% CI 1.27–32.92) or as linear or segmental non-mass enhancement (NME, versus focal or regional,
p
= 0.008).
Conclusion
Our data support the recommendation that ADH and LCIS on MRI-guided biopsy warrant surgical excision due to high upgrade rates. HRLs that present as T2 hypointense, or as linear or segmental NME, should be viewed with suspicion as these were associated with higher upgrade rates to malignancy.
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