Stereotactic body radiotherapy for metastatic sarcoma to the lung: adding to the arsenal of local therapy.

INTRODUCTION: Conventional treatment of pulmonary metastatic sarcoma primarily involves surgery, with systemic therapy added in select patients. However, broader applications of radiation therapy techniques have prompted investigation into the use of stereotactic body radiotherapy (SBRT) for treatment of metastatic sarcoma, an attractive non-invasive intervention with potential for lower rates of adverse events than surgery. Current data are limited to retrospective analyses. This study analyzed 2-year local control and overall survival and adverse events in patients prospectively treated with SBRT to pulmonary sarcoma metastases. METHODS: Patients prospectively treated with SBRT to the lung for biopsy-proven metastatic sarcoma at a single institution from 2010 to 2022 were included. SBRT dose/fractionation treatment regimens ranged from 34 to 54 Gy in 1-10 fractions using photons. Local recurrence, local progression-free survival (LPFS) and overall survival (OS) were calculated from the end of SBRT. Univariable analysis (UVA) was performed using the log-rank test. Multivariable analysis (MVA) was performed using the Cox proportional hazards model. Adverse events due to SBRT were graded based on the Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: Eighteen patients with metastatic sarcoma were treated to 26 pulmonary metastases. The median local progression-free survival was not met. The median overall survival was not met. The local control rate at 2 years was 96%. 2-year LPFS was 95.5% and OS was 74%. Three patients (16.7%) developed grade 1 adverse events from SBRT. There were no adverse events attributed to radiation that were grade 2 or higher. CONCLUSION: We report prospective data demonstrating that SBRT for sarcoma pulmonary metastases affords a high rate of local control and low toxicity, consistent with prior sarcoma SBRT retrospective data. This study adds to the wealth of information on SBRT in a radioresistant tumor. Though largely limited to retrospective reviews, current data indicate high rates of local control with favorable toxicity profiles. Therefore, SBRT for pulmonary sarcoma metastases may be considered for properly selected patients.

Analysis and Evaluation of a Deep Learning Reconstruction Approach with Denoising for Orthopedic MRI.

PURPOSE: To evaluate two settings (noise reduction of 50% or 75%) of a deep learning (DL) reconstruction model relative to each other and to conventional MR image reconstructions on clinical orthopedic MRI datasets. MATERIALS AND METHODS: This retrospective study included 54 patients who underwent two-dimensional fast spin-echo MRI for hip (n = 22; mean age, 44 years ± 13 [standard deviation]; nine men) or shoulder (n = 32; mean age, 56 years ± 17; 17 men) conditions between March 2019 and June 2020. MR images were reconstructed with conventional methods and the vendor-provided and commercially available DL model applied with 50% and 75% noise reduction settings (DL 50 and DL 75, respectively). Quantitative analytics, including relative anatomic edge sharpness, relative signal-to-noise ratio (rSNR), and relative contrast-to-noise ratio (rCNR) were computed for each dataset. In addition, the image sets were randomized, blinded, and presented to three board-certified musculoskeletal radiologists for ranking based on overall image quality and diagnostic confidence. Statistical analysis was performed with a nonparametric hypothesis comparing derived quantitative metrics from each reconstruction approach. In addition, inter- and intrarater agreement analysis was performed on the radiologists' rankings. RESULTS: Both denoising settings of the DL reconstruction showed improved edge sharpness, rSNR, and rCNR relative to the conventional reconstructions. The reader rankings demonstrated strong agreement, with both DL reconstructions outperforming the conventional approach (Gwet agreement coefficient = 0.98). However, there was lower agreement between the readers on which DL reconstruction denoising setting produced higher-quality images (Gwet agreement coefficient = 0.31 for DL 50 and 0.35 for DL 75). CONCLUSION: The vendor-provided DL MRI reconstruction showed higher edge sharpness, rSNR, and rCNR in comparison with conventional methods; however, optimal levels of denoising may need to be further assessed.Keywords: MRI Reconstruction Method, Deep Learning, Image Analysis, Signal-to-Noise Ratio, MR-Imaging, Neural Networks, Hip, Shoulder, Physics, Observer Performance, Technology Assessment Supplemental material is available for this article. © RSNA, 2021.

Multispectral diffusion-weighted imaging near metal implants.

PURPOSE: The need for diffusion-weighted-imaging (DWI) near metallic implants is becoming increasingly relevant for a variety of clinical diagnostic applications. Conventional DWI methods are significantly hindered by metal-induced image artifacts. A novel approach relying on multispectral susceptibility artifact reduction techniques is presented to address this unmet need. METHODS: DWI near metal implants is achieved through a combination of several advanced MRI acquisition technologies. Previously described approaches to Carr-Purcell-Meiboom-Gill spin-echo train DWI sequences using the periodically rotated overlapping parallel lines with enhanced reconstruction are combined with multispectral-imaging metal artifact reduction principles to provide DWI with substantially reduced artifact levels. The presented methods are applied to limited sets of slices over areas of sarcoma risk near six implanted devices. RESULTS: Using the presented methods, DWI assessment without bulk image distortions is demonstrated in the immediate vicinity of metallic interfaces. In one subject, the apparent diffusion coefficient was reduced in a region of suspected sarcoma directly adjacent to fixation hardware. CONCLUSIONS: An initial demonstration of minimal-artifact multispectral DWI in the near vicinity of metallic hardware is described and successfully demonstrated on clinical subjects. Magn Reson Med 79:987-993, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Dedifferentiated chondrosarcoma of bone with prominent rhabdoid component.

Dedifferentiated chondrosarcomas (DDCS) are rare lesions, defined as tumors having a low-grade chondrosarcomatous component with an abrupt transition to a high-grade sarcoma. Although "malignant fibrous histiocytoma" (undifferentiated pleomorphic sarcoma) is the most common high grade saromatous component, many different types of sarcoma have been described. We present a case of dedifferentiated chondrosarcoma with rhabdomyosarcomatous differentiation harboring a prominent rhabdoid tumor component. To our knowledge, rhabdoid morphology in dedifferentiated chondrosarcoma has not been described in the English-language literature. The pathologic and radiologic features of this case are presented.

Glenoid avulsion of the glenohumeral ligament (GAGL): a case report and review of the anatomy.

Shoulder dislocations are frequently seen in the general population and can be a cause of instability. Instability can lead to debilitating symptoms and morbidity as a result of progressive damage to the shoulder. Anterior shoulder dislocations are the most frequent type of dislocations and have been studied extensively with MRI. The soft tissue Bankart lesion is the most well-known entity associated with anterior instability; however, additional structural lesions arising from traumatic events have been described in recent literature which also predispose to anterior shoulder instability. One of these lesions, the glenoid avulsion of the glenohumeral ligament (GAGL), involves avulsion of the inferior glenohumeral ligament from the glenoid and involves separation from an intact labrum. In contrast to the Bankart lesion, there has been limited discussion of the GAGL lesion in the literature and very few imaging examples. We report a case of a GAGL diagnosed on MRI and confirmed with arthroscopy. It is discussed in the context of the anatomy of the inferior glenohumeral ligament and the imaging findings.

The prevalence of chondrocalcinosis of the symphysis pubis on CT scan and correlation with calcium pyrophosphate dihydrate crystal deposition disease.

Calcium pyrophosphate dihydrate (CPP) crystal deposition in the articular cartilage can often be seen radiographically as chondrocalcinosis (CC). CPP crystals preferentially deposit in fibrocartilages such as the knee menisci and symphysis pubis (SP). We sought to determine the prevalence of CC in the SP on computed tomography (CT) of the abdomen and pelvis. This retrospective study involved readings on 1070 consecutive CTs of the abdomen and pelvis performed over 3 months in patients over 65 years of age. Medical records of 226 patients found to have CC were reviewed to determine age, gender, documentation of CPPD on problem lists or in medical histories, and whether radiology readings of the CTs mentioned CC. SP CC was identified in 21.1 % (226/1070) of consecutive CT scans with the mean age of CT+ patients being 78.6. Of the 226 patients with SP CC, the observation of CC was documented in only 5.3 % (12/226) of the radiology reports. Of the 12 instances in which the radiology reports mentioned CC, this observation was never (0/12) transmitted to the medical history or problem list. The prevalence of SP CC in patients older than 65 was 21.1 %. Since the majority of CTs of the abdomen and pelvis are not ordered for evaluation of musculoskeletal conditions, this is likely a true prevalence without selection bias. When CC of the SP was present on images, radiologists routinely overlooked or chose not to report CC. Even in the rare instances when it was reported, that information was not added to the medical history or problem list. There are several clinical situations (e.g., acute monoarthritis or atypical osteoarthritis) in which recognizing that a patient has CPP deposition would be useful. Taking the time to review images may yield clinically important findings that are not mentioned anywhere on the patient chart.

Iliotibial band avulsion fracture: a case report with differential diagnosis.

Avulsion injuries of the knee are common sequelae of significant trauma given the number of ligamentous and tendinous insertions around the joint. Commonly discussed avulsion fractures of the lateral knee include the Segond fracture of the lateral tibial plateau and the arcuate complex avulsion fracture of the fibular styloid process. A less common avulsion fracture is the iliotibial (IT) band avulsion fracture involving the anterolateral corner of the tibia (Gerdy's tubercle). It is crucial to identify IT band avulsion fractures because of the frequent associated internal derangements of the knee. This case report describes the imaging of an acute IT band avulsion fracture and compares these findings with other lateral knee avulsion fractures.