A Case of Radiation-Induced Brachial Plexopathy Below the Tolerance Dose.

This case report details a rare instance of radiation-induced brachial plexopathy (RIBP) occurring below the typical tolerance dose in a 55-year-old woman following chemoradiotherapy for apical non-small cell lung carcinoma. Despite receiving a radiation dose considered safe (47-48 Gray in 25 fractions), she developed sensory abnormalities and motor weakness in the right upper limb. The diagnostic distinction between RIBP and tumor recurrence was achieved using MRI, which showed characteristic features of radiation-induced damage. The patient's medical history included smoking and rheumatoid arthritis, highlighting the role of patient-specific factors in the development of RIBP. The case underscores the importance of recognizing RIBP as a potential diagnosis in patients with new-onset brachial plexopathy post-radiation therapy, even when radiation exposure is within conventional safety limits. This report contributes to the literature by demonstrating that RIBP can occur at lower-than-expected radiation doses, especially in the presence of contributing factors like neurotoxic chemotherapy and individual patient risks. It emphasizes the need for careful assessment and management in such cases to distinguish between RIBP and cancer recurrence.

Intraventricular Pleomorphic Xanthoastrocytoma: A Case Report and Systemic Review.

We present a unique case of a 45-year-old male with cerebral palsy, who experienced walking difficulties and altered consciousness. The initial MRI revealed an intraventricular mass that rapidly enlarged over a month, consisting of two distinct components with different characteristics on CT and MRI, and was associated with agenesis of the corpus callosum. Despite initial treatment, surgical intervention was necessary, where preoperative imaging suggested an exophytically growing glioblastoma. However, postsurgical pathological examination identified the mass as pleomorphic xanthoastrocytoma (PXA), World Health Organization (WHO) Classification of Tumours of the Central Nervous System (CNS) grade 3. This study is notable for its rarity and complexity, challenging standard diagnostic approaches. PXA is an uncommon astrocytic tumor, and its occurrence intraventricularly is extremely rare. This study highlights its unique imaging features and the critical role of MRI in preoperative assessment, underlining the tumor's unusual intraventricular location, and its relationship with corpus callosum agenesis. Our comprehensive review of PXA's history and imaging spectrum offers valuable insights for neuroradiologists and neurosurgeons, emphasizing the diagnostic challenges of such rare tumor locations and the importance of meticulous MRI analysis for accurate diagnosis.

[18F]FDG PET/CT Findings of Mass-Forming Actinomycosis in an Uncontrolled Diabetic Patient.

We report a case of cervicofacial actinomycosis mimicking malignant sarcoma in a 78-year-old man with diabetes. High lesion uptake and decreased cerebral uptake on [18F]FDG PET/CT provide a potentially important diagnostic clue suggesting infectious disease in a poorly controlled diabetic patient.

Phase I/IIa trial of 18F-prostate specific membrane antigen (PSMA) 1007 PET/CT in healthy volunteers and prostate cancer patients.

OBJECTIVE: 18F-PSMA 1007 is a promising PET tracer for prostate cancer. We aimed to examine the safety, biodistribution, radiation dosimetry, and clinical effectiveness in Japanese healthy volunteers and patients with prostate cancer. METHODS: Part A evaluated the pharmacokinetics and exposure doses in three healthy volunteers. Part B evaluated the diagnostic accuracy in patients with untreated preoperative prostate cancer (Cohort 1, n = 7) and patients with biochemical recurrence (Cohort 2, n = 3). All subjects received a single dose of 3.7 MBq/kg 18F-PSMA 1007. Results: 18F-PSMA 1007 was found to be safe and well tolerated in all subjects. No serous AEs or drug-related AEs were identified during the present study. The average blood radioactivity concentration reached a maximum of 47.87 ± 1.05 (percentage of injected dose [%ID]/ml) at 5 min and then decreased to 1.60 ± 0.78 in 6 h. The systemic radioactivity reached a maximum of 211.05 ± 6.77 (%ID$\times$103) at 5 min and decreased to 7.18 ± 3.91 in 6 h. The sensitivity and positive predictive value were 100% and 100% based on both pathologic and imaging confirmation as gold standard. In Cohort 1, 15 primary foci (11.9%) were >5 mm in the largest diameter and identified in 39 of 126 segments (30.1%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for 60 min uptake time acquisition were 80.0, 96.5, 91.4, 91.2 and 91.3%, respectively. CONCLUSIONS: Our study revealed that 18F-PSMA 1007 was safe, well tolerated and showed high accuracy in the diagnosis of prostate cancer.

Deep convolutional neural network for differentiating between sarcoidosis and lymphoma based on [18F]FDG maximum-intensity projection images.

OBJECTIVES: To compare the [18F]FDG PET/CT findings of untreated sarcoidosis and malignant lymphoma (ML) and develop convolutional neural network (CNN) models to differentiate between these diseases using maximum intensity projection (MIP) [18F]FDG PET images. METHODS: We retrospectively collected data on consecutive patients newly diagnosed with sarcoidosis and ML who underwent [18F]FDG PET/CT before treatment. Two nuclear radiologists reviewed the images. CNN models were created using MIP PET images and evaluated with k-fold cross-validation. The points of interest were visualized using gradient-weighted class activation mapping (Grad-CAM). RESULTS: A total of 56 patients with sarcoidosis and 62 patients with ML were included. Patients with sarcoidosis had more prominent FDG accumulation in the mediastinal lymph nodes and lung lesions, while those with ML had more prominent accumulation in the cervical lymph nodes (all p < 0.001). For the mediastinal lymph nodes, sarcoidosis patients had significant FDG accumulation in the level 2, 4, 7, and 10 lymph nodes (all p < 0.01). Otherwise, the accumulation in ML patients tended to be in the level 1 lymph nodes (p = 0.08). The CNN model using frontal and lateral MIP images achieved an average accuracy of 0.890 (95% CI: 0.804-0.977), a sensitivity of 0.898 (95% CI: 0.782-1.000), a specificity of 0.907 (95% CI: 0.799-1.000), and an area under the curve of 0.963 (95% CI: 0.899-1.000). Grad-CAM showed that the model focused on the sites of abnormal FDG accumulation. CONCLUSIONS: CNN models based on differences in FDG accumulation sites archive high performance in differentiating between sarcoidosis and ML. CLINICAL RELEVANCE STATEMENT: We developed a CNN model using MIP images of [18F]FDG PET/CT to distinguish between sarcoidosis and malignant lymphoma. It achieved high performance and could be useful in diagnosing diseases with involvement across organs and lymph nodes. KEY POINTS: • There are differences in FDG distribution when comparing whole-body [18F]FDG PET/CT findings in patients with sarcoidosis and malignant lymphoma before treatment. • Convolutional neural networks, a type of deep learning technique, trained with maximum-intensity projection PET images from two angles showed high performance. • A deep learning model that utilizes differences in FDG distribution may be helpful in differentiating between diseases with lesions that are characteristically widespread among organs and lymph nodes.

Correlation between choline kinase alpha expression and 11C-choline accumulation in breast cancer using positron emission tomography/computed tomography: a retrospective study.

Choline kinase (CK) is reportedly overexpressed in various malignancies. Among its isoforms, CKα overexpression is presumably related to oncogenic change. Choline positron emission tomography (PET) is reportedly useful for detecting and evaluating therapy outcomes in malignancies. In this study, we investigated the correlation between CKα expression and 11C-choline accumulation in breast cancer cells. We also compared the CKα expression level with other pathological findings for investigating tumour activity. Fifty-six patients with breast cancer (mean age: 51 years) who underwent their first medical examination between May 2007 and December 2008 were enrolled. All the patients underwent 11C-choline PET/computed tomography imaging prior to surgery. The maximum standardised uptake value was recorded for evaluating 11C-choline accumulation. The intensity of CKα expression was classified using immunostaining. A significant correlation was observed between CKα expression and 11C-choline accumulation (P < 0.0001). A comparison of breast cancer mortality demonstrated that strong CKα expression was associated with a shorter survival time (P < 0.0001). 11C-choline accumulation was also negatively correlated with survival time (P < 0.0001). Tumours with strong CKα expression are reportedly highly active in breast cancer. A correlation was observed between CKα expression and 11C-choline accumulation, suggesting their role as prognostic indicators of breast cancer.

Pulmonary Vein Stenosis after Catheter Ablation for Atrial Fibrillation: An Early Diagnosis Using Unenhanced Computed Tomography.

Pulmonary vein stenosis (PVS) is a serious complication of catheter ablation (CA) for atrial fibrillation (AF). PVS generally occurs several months after CA and presents with non-specific symptoms and imaging findings. There have been reports of delayed diagnoses due to a misdiagnosis as infection, interstitial pneumonia, or organizing pneumonia. We introduced six cases of PVS after CA, all of which showed narrowing of the unilateral pulmonary vessels with or without lobar volume loss in the left lung on unenhanced computed tomography. We report these findings as important results indicating the possibility of PVS after CA for AF and contributing to the early diagnosis and management of PVS.

Imaging Features of Ectopic Tissues and Their Complications: Embryologic and Anatomic Approach.

Ectopic tissue is an anatomic abnormality in which tissue develops in an area outside its normal location. It is primarily caused by abnormalities during the process of embryologic development. Although the majority of individuals with ectopic tissues remain asymptomatic, various symptoms and associated complications can occur. Failure in normal embryologic development leads to loss of normal physiologic function or may result in harmful functions such as ectopic hormonal secretion in the ectopic pituitary adenoma. Ectopic tissues may also frequently mimic tumors. For example, developmental abnormalities in the pharyngeal pouches may result in an ectopic parathyroid gland and ectopic thymus, both of which are frequently misdiagnosed as tumors. Adequate knowledge of embryology is essential for understanding the differential diagnoses of ectopic tissues and facilitating appropriate management. The authors summarize the embryologic development and pathogenesis of ectopic tissues by using illustrations to facilitate a deeper understanding of embryologic development and anatomy. Characteristic imaging findings (US, CT, MRI, and scintigraphy) are described for ectopic tissues of the brain, head, neck, thorax, abdomen, and pelvis by focusing on common conditions that radiologists may encounter in daily practice and their differential diagnoses. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

The potential value of thallium-201 scintigraphy in the diagnosis of squamous cell carcinoma arising from extensive pyoderma.

Squamous cell carcinoma (SCC) arises from a variety of premalignant conditions, including pyoderma. However, an accurate diagnosis of SCC is sometimes challenging due to indistinguishable inflammatory lesions. Here, we present a case of SCC arising from extensive pyoderma, which was successfully diagnosed by taking advantage of thallium-201 scintigraphy. A 49-year-old man presented with an elevated tumor on his right buttock. Computed tomography (CT) and enhanced magnetic resonance imaging (MRI) identified the tumor, but many indistinguishable lesions were also found around the tumor. Histopathology revealed an atypical proliferation of keratinocytes with cancer pearls inside the tumor nests, while histopathology of nodules around the tumor revealed inflammatory tissues. Positron emission tomography CT (PET/CT) revealed an accumulation of 2-deoxy-2-[18 F]-D-glucose at the axillae and inguinal nodes, and at subcutaneous tissues in addition to the tumor. From the CT, enhanced MRI, and PET/CT analyses it was impossible to differentiate many scattered subcutaneous nodules on the trunk from SCCs. However, thallium-201 scintigraphy identified only the tumor and found no accumulation in other nodules. This finding suggests that thallium-201 scintigraphy is useful for the diagnosis of SCC by excluding false-positive signals detected by other imaging technologies.

Enhancement of 18F-Fluorodeoxyglucose PET Image Quality by Deep-Learning-Based Image Reconstruction Using Advanced Intelligent Clear-IQ Engine in Semiconductor-Based PET/CT Scanners.

Deep learning (DL) image quality improvement has been studied for application to 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). It is unclear, however, whether DL can increase the quality of images obtained with semiconductor-based PET/CT scanners. This study aimed to compare the quality of semiconductor-based PET/CT scanner images obtained by DL-based technology and conventional OSEM image with Gaussian postfilter. For DL-based data processing implementation, we used Advanced Intelligent Clear-IQ Engine (AiCE, Canon Medical Systems, Tochigi, Japan) and for OSEM images, Gaussian postfilter of 3 mm FWHM is used. Thirty patients who underwent semiconductor-based PET/CT scanner imaging between May 6, 2021, and May 19, 2021, were enrolled. We compared AiCE images and OSEM images and scored them for delineation, image noise, and overall image quality. We also measured standardized uptake values (SUVs) in tumors and healthy tissues and compared them between AiCE and OSEM. AiCE images scored significantly higher than OSEM images for delineation, image noise, and overall image quality. The Fleiss kappa value for the interobserver agreement was 0.57. Among the 21 SUV measurements in healthy organs, 11 (52.4%) measurements were significantly different between AiCE and OSEM images. More pathological lesions were detected in AiCE images as compared with OSEM images, with AiCE images showing higher SUVs for pathological lesions than OSEM images. AiCE can improve the quality of images acquired with semiconductor-based PET/CT scanners, including the noise level, contrast, and tumor detection capability.

Branch-like enhancement on contrast enhanced MRI is a specific finding of cerebellar lymphoma compared with other pathologies.

Branch-like enhancement (BLE) on contrast-enhanced (CE) magnetic resonance imaging (MRI) was found to be effective in differentiating primary central nervous system lymphoma (PCNSL) from high-grade glioma (HGG) in the cerebellum. However, whether it can be applied to assessments of secondary central nervous system lymphoma (SCNSL), or other cerebellar lesions is unknown. Hence, we retrospectively reviewed cerebellar masses to investigate the use of BLE in differentiating cerebellar lymphoma (CL), both primary and secondary, from other lesions. Two reviewers qualitatively evaluated the presence and degree of BLE on CE-T1 weighted imaging (T1WI). If multiple views were available, we determined the view in which BLE was the most visible. Seventy-five patients with the following pathologies were identified:17 patients with CL, 30 patients with metastasis, 12 patients with hemangioblastoma, 9 patients with HGG, and 7 patients with others. Twelve patients presented with PCNSL and five with SCNSL. Of 17 patients with CL, 15 (88%) had BLE, whereas three (5%) out of 58 patients in the non-CL group showed BLE. In patients who underwent three-dimensional-CE-T1WI, BLE was the most visible on the sagittal image. In conclusion, BLE is a highly specific finding for CL and the sagittal image is important in evaluating this finding.

A Rare Case of Radiation-Induced Liver Disease in Treated Abdominal Lymphoma Showing High [18F]FDG Avidity and Low EOB Uptake Proportional to the Irradiation Dose.

A 44-year-old woman presented with high [18F]FDG uptake liver lesion after six courses of R-CHOP and radiotherapy for abdominal DLBCL, which was misdiagnosed as a hepatic invasion. EOB-MRI showed slight T2 hyperintensity, low-intensity DWI, and decreased EOB uptake in the hepatocellular phase. Compared with the pretreatment planning CT, the liver lesion coincided with the area of >40.5 Gy, resulting in the diagnosis of RILD. At the follow-up [18F]FDG PET/CT 7 months after irradiation, the abnormal liver uptake disappeared. Comparing [18F]FDG PET/CT, EOB-MRI, and planning CT can lead to the correct diagnosis of RILD and avoid unnecessary biopsies and treatment changes.

Safety and response after peptide receptor radionuclide therapy with 177 Lu-DOTATATE for neuroendocrine tumors in phase 1/2 prospective Japanese trial.

BACKGROUND: The present prospective phase 1/2 study aimed to elucidate the efficacy and safety of 177 Lu-DOTATATE (four cycles of 7.4 GBq) in Japanese patients with unresectable, progressive neuroendocrine tumors (NETs). METHODS: From April 2018 to October 2020, 15 patients with advanced NETs (five midgut, eight pancreatic, and two lung NETs) were enrolled. Objective response rate (ORR), progression-free survival (PFS), and adverse events (AEs) were evaluated. Pharmacokinetics and dosimetry were also evaluated in three midgut patients. RESULTS: The mean absorbed doses of 177 Lu-DOTATATE to the kidneys (20.7 Gy/29.6 GBq) and the bone marrow (0.631 Gy/29.6 GBq) were within the radiation tolerance doses. The ORR of the whole population was 53% (90% CI, 30%-76%). ORRs of the midgut and non-midgut NETs were 60% (90% CI, 19%-92%) and 50% (90% CI, 22%-78%), respectively. There was no difference in the maximum reduction rate of the sum of the target lesion diameters between patients with midgut and non-midgut NET. The median PFS was not reached; the PFS rate at 52 weeks was 80% (90% CI, 56.1%-91.7%). AEs of Grade 3 or higher were lymphopenia (47%) and leukopenia (7%). CONCLUSION: 177 Lu-DOTATATE demonstrated remarkable tumor shrinkage and tolerability in Japanese patients with advanced NETs.

Noninferiority of Microhook to Trabectome: Trabectome versus Ab Interno Microhook Trabeculotomy Comparative Study (Tram Trac Study).

PURPOSE: To elucidate the noninferiority of ab interno microhook trabeculotomy (µTLO) using a recently developed reusable stainless spatula-type microhook device to incise the trabecular meshwork to Trabectome (Neomeix, Inc) surgery in terms of the 1-year postoperative outcomes of Japanese patients with glaucoma by means of propensity score analyses. DESIGN: Multicenter, retrospective cohort study. PARTICIPANTS: We enrolled 553 and 392 patients who underwent Trabectome surgery and µTLO, respectively, between January 2014 and March 2020 at 10 facilities. METHODS: Logistic regression analysis was conducted to calculate the propensity score, which indicates the likelihood of treatment assignment (Trabectome or µTLO). We set the following factors as outcome-related covariates: age, sex, facility, glaucoma disease types, preoperative intraocular pressure (IOP), glaucoma drug score, mean deviation of Humphrey visual field test results, antithrombotic drug use, the presence or absence of combined cataract surgery, and incision range of the trabecular meshwork (1 or 2 quadrants). We analyzed 4 different methods (matching, inverse probability of treatment weighting [IPTW], stratification, and regression adjustment) using the propensity score. We set 15% as the noninferiority margin based on previous Trabectome meta-analysis results. MAIN OUTCOME MEASURES: The primary outcome was surgical success at 1 year after surgery. We defined surgical success as satisfying all 3 criteria: (1) IOP within 5 to 21 mmHg, (2) IOP reduction of 20% or more from preoperative IOP, and (3) no additional glaucoma surgery. RESULTS: The 95% confidence interval of risk difference of surgical failure in µTLO in reference to Trabectome surgery was -12.1% to +9.5% in matching, -12.7% to +11.1% in IPTW, -12.2 to +7.0 in stratification, and -9.7% to +8.1% in regression adjustment, all of which fell within the predetermined noninferiority margin of 15%. CONCLUSIONS: Surgical success of µTLO at 1 year after was not inferior to that of Trabectome surgery.

Image quality and quantification accuracy dependence on patient body mass in 89Zr PET/CT imaging.

BACKGROUND: This study was conducted to clarify how patient body mass affects the image quality and quantification accuracy of images obtained using 89Zr PET/CT. 89Zr PET/CT images from time-of-flight (TOF) PET/CT and semiconductor (SC) PET/CT were obtained using three types (M, L, LL; corresponding to increasing patient body weight) of custom-made body phantoms designed similarly to the National Electrical Manufacturers Association (NEMA) IEC body phantom. The phantom data were analyzed visually and quantitatively to derive image quality metrics, namely detectability of the 10-mm-diameter hot sphere, percent contrast for the 10-mm-diameter hot sphere (QH,10 mm), percent background variability (N10mm), contrast-to-noise ratio (QH,10 mm/N10mm), and coefficient of variation of the background area (CVBG). RESULTS: Visual assessment revealed that all the 10-mm-diameter hot spheres of the three types of phantoms were identifiable on both SC and TOF PET/CT images. The N10mm and CVBG values were within the proposed reference levels, and decreased with acquisition duration for both PET/CT types. At 10-min acquisition, the QH,10 mm/N10mm of SC PET/CT was greater than the proposed reference level in all phantoms. However, the QH,10 mm/N10mm of TOF PET/CT was greater than the proposed reference level in M-type phantom alone. All the SUVBG values were within 1.00 ± 0.05 for both PET/CT types. CONCLUSIONS: This study showed that the image quality and quantification accuracy depend on the patient's body mass, suggesting that acquisition time on 89Zr PET/CT should be changed according to the patient's body mass.

A useful case of ultrasound-guided axillary lymph node aspiration in a breast cancer patient with improved needle visibility.

Ultrasound-guided, lymph node, fine-needle aspiration cytology is important in diagnosing axillary lymph node metastasis in breast cancer. However, poor needle visibility can render the procedure difficult. We describe a case in which state-of-the-art enhancement techniques using matrix linear probes can provide better needle visibility and improve the certainty and efficiency of the examination.