Yuji Nakamoto

Preoperative breast magnetic resonance imaging (MRI) is the most sensitive modality for assessing disease extent in newly diagnosed breast cancer, detecting additional ipsilateral disease in approximately 20% of patients. While its impact on patients’ prognosis is debated, MRI may refine surgical management when it is appropriately evaluated. This review provides a practical framework for optimizing MRI interpretation for individualized surgical planning, incorporating the updated American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) v2025 recommendations. Key updates in BI-RADS v2025 include the introduction of “Additional Close Findings” to streamline the management of suspicious lesions within 2.0 cm of the index cancer. For oncoplastic procedures, MRI provides critical metrics: a tumor-nipple distance of > 1.0 cm has been reported as a significant threshold under specific study conditions for predicting nipple involvement in nipple-sparing mastectomy, while an MRI-to-skin distance of 5 mm is a suggested threshold for predicting margin positivity in skin-sparing mastectomy. This review also addresses the assessment of pectoralis muscle involvement and the new BI-RADS section dedicated to lymph node evaluation. Furthermore, MRI is highlighted as an essential tool for identifying eligible candidates for radiofrequency ablation by precisely excluding multifocality and extensive intraductal components to satisfy strict clinical criteria. The integration of these standardized, surgically-relevant metrics allows radiologists to provide a detailed anatomical roadmap, which is essential to maximize cosmetic outcomes through conservative mastectomy techniques without compromising oncological safety.

Certain brain tumors exhibit cystic components. MRI is particularly effective in characterizing the location, enhancement, and morphology of these cystic regions, enabling radiologists to narrow the differential diagnosis. Cystic components are often associated with circumscribed tumors and may be linked to favorable outcomes. High-grade tumors such as glioblastoma can also occasionally exhibit cystic components. Here, we summarize the imaging characteristics of representative cystic brain intraparenchymal neoplasms, including hemangioblastoma, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, ganglioglioma, desmoplastic infantile ganglioglioma/astrocytoma, central neurocytoma, dysembryoplastic neuroepithelial tumor, ependymoma, glioblastoma, and metastases. This review aims to provide MRI features that facilitate differentiation of these tumors and support appropriate clinical management.

Recent progress in nuclear medicine has been driven by continuous advances in radiotracers, imaging technologies, and radiopharmaceutical therapies, leading to an expansion of clinical applications supported by an increasing body of evidence. In particular, systematic reviews and meta-analyses have played an important role in quantitatively evaluating the clinical value of these developments. This narrative review provides an overview of recent meta-analytic evidence in nuclear medicine, with a primary focus on oncologic applications, while briefly addressing developments in cardiology and neurology. In oncology, positron emission tomography (PET)/computed tomography (CT) using fluorodeoxyglucose (FDG) has become an established imaging modality for post-treatment assessment across various malignancies. Meta-analyses indicate that volumetric metabolic parameters, such as metabolic tumor volume and total lesion glycolysis, are more consistently associated with clinical outcomes than conventional single-voxel metrics. In addition, the interim and post-therapy metabolic response, assessed by FDG PET/CT, provides clinically relevant prognostic information and may contribute to treatment monitoring. Beyond FDG, tumor-targeted PET tracers, including prostate-specific membrane antigen and somatostatin receptor ligands, have demonstrated improved diagnostic performance in specific malignancies, and emerging tracers such as fibroblast activation protein inhibitors represent promising future directions. Radiopharmaceutical therapy has also shown notable progress, with meta-analytic evidence supporting the effectiveness and acceptable safety of peptide receptor radionuclide therapy for neuroendocrine tumors, as well as for advanced prostate cancer. In nuclear cardiology and neurology, advances in PET and single photon emission CT technologies have enabled more precise disease characterization, although their clinical roles continue to evolve. Overall, accumulating meta-analytic evidence supports the growing clinical importance of nuclear medicine. Continued methodological refinement and further evidence generation will be essential to optimize patient management in routine clinical practice.

Background: There has been growing interest in the limited resection of early-stage lung cancer. Imaging-based preoperative risk stratification is expected to improve outcomes, but has not yet been well established. This study aimed to develop an imaging-based model for predicting high-risk histopathological features in early T-stage lung adenocarcinoma to identify low-risk patients. Methods: We retrospectively enrolled patients with cTis or cT1 N0M0 resected adenocarcinomas who underwent thin-slice computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) at two institutions (Kyoto University Hospital as the training set and Hyogo Prefectural Amagasaki General Medical Center as the external test set). The thin-slice CT parameters analyzed included volume-based consolidation-to-tumor ratio (vCTR), diameter-based CTR (dCTR), tumor volume (TV), and doubling time (DT); while the FDG-PET/CT parameters comprised maximum standardized-uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Histopathological risk-positive lesions were defined as positive for pleural, vessel, or lymphatic invasion; spread through air space (STAS); and International Association for the Study of Lung Cancer (IASLC) grade 3. Logistic regression was used to develop predictive models, which were then tested on the external test set. Results: We analyzed 190 lesions in 174 patients for the training set, and 34 lesions in 28 patients for the external test set. The parameters vCTR and SUVmax showed the highest area under the receiver operating characteristics curve (AUC) values for risk-positive lesions (vCTR >58%: 0.83; SUVmax >2.0: 0.87) as independent predictors. The AUCs of our model (predictors: vCTR, SUVmax) were 0.87 and 0.85 in the training and external test sets, respectively. Conclusions: We developed and externally validated an imaging-based model for predicting high-risk histopathological features in early T-stage lung adenocarcinoma. This model may prove valuable for identifying suitable candidate patients for limited surgery.

A 14-year-old girl underwent bilateral living-donor lobar lung transplants (LDLLT) from each parent for bronchiolitis obliterans following hematopoietic stem cell transplantation (HSCT). Pulmonary perfusion scintigraphy demonstrated a marked reduction in blood flow in the father-derived graft, which subsequently collapsed and was diagnosed as chronic lung allograft dysfunction (CLAD), whereas the mother-derived graft remained stable and functional. The HSCT was performed with the mother’s stem cells, theoretically preventing rejection of the mother’s graft. This case highlights the unique immunologic dynamics arising from donor selection in HSCT and LDLLT, and underscores the usefulness of scintigraphy in the early detection of CLAD.

This correction addresses several errors identified in the original publication