Development and implementation of optimized endogenous contrast sequences for delineation in adaptive radiotherapy on a 1.5T MR-linear-accelerator: a prospective R-IDEAL stage 0-2a quantitative/qualitative evaluation of in vivo site-specific quality-assurance using a 3D T2 fat-suppressed platform for head and neck cancer.

Purpose: To improve segmentation accuracy in head and neck cancer (HNC) radiotherapy treatment planning for the 1.5T hybrid magnetic resonance imaging/linear accelerator (MR-Linac), three-dimensional (3D), T2-weighted, fat-suppressed magnetic resonance imaging sequences were developed and optimized. Approach: After initial testing, spectral attenuated inversion recovery (SPAIR) was chosen as the fat suppression technique. Five candidate SPAIR sequences and a nonsuppressed, T2-weighted sequence were acquired for five HNC patients using a 1.5T MR-Linac. MR physicists identified persistent artifacts in two of the SPAIR sequences, so the remaining three SPAIR sequences were further analyzed. The gross primary tumor volume, metastatic lymph nodes, parotid glands, and pterygoid muscles were delineated using five segmentors. A robust image quality analysis platform was developed to objectively score the SPAIR sequences on the basis of qualitative and quantitative metrics. Results: Sequences were analyzed for the signal-to-noise ratio and the contrast-to-noise ratio and compared with fat and muscle, conspicuity, pairwise distance metrics, and segmentor assessments. In this analysis, the nonsuppressed sequence was inferior to each of the SPAIR sequences for the primary tumor, lymph nodes, and parotid glands, but it was superior for the pterygoid muscles. The SPAIR sequence that received the highest combined score among the analysis categories was recommended to Unity MR-Linac users for HNC radiotherapy treatment planning. Conclusions: Our study led to two developments: an optimized, 3D, T2-weighted, fat-suppressed sequence that can be disseminated to Unity MR-Linac users and a robust image quality analysis pathway that can be used to objectively score SPAIR sequences and can be customized and generalized to any image quality optimization protocol. Improved segmentation accuracy with the proposed SPAIR sequence will potentially lead to improved treatment outcomes and reduced toxicity for patients by maximizing the target coverage and minimizing the radiation exposure of organs at risk.

Extramural venous invasion: a novel magnetic resonance imaging biomarker for adverse pathology in bladder cancer.

Extramural venous invasion (EMVI) recognized on magnetic resonance imaging (MRI) is an unequivocal biomarker for detecting adverse outcomes in rectal cancer: however it has not yet been explored in the area of bladder cancer. In this study, we assessed the feasibility of identifying EMVI findings on MRI in patients with bladder cancer and its avail in identifying adverse pathology. In this single-institution retrospective study, the MRI findings inclusive of EMVI was described in patients with bladder cancer that had available imaging between January 2018 and June 2020. Patient demographic and clinical information were retrieved from our electronic medical records system. Histopathologic features frequently associated with poor outcomes including lymphovascular invasion (LVI), variant histology, muscle invasive bladder cancer (MIBC), and extravesical disease (EV) were compared to MRI-EMVI. A total of 38 patients were enrolled in the study, with a median age of 73 years (range 50-101), 76% were male and 23% were females. EMVI was identified in 23 (62%) patients. There was a significant association between EMVI and MIBC (OR = 5.30, CI = 1.11-25.36; P = 0.036), and extravesical disease (OR = 17.77, CI = 2.37-133; P = 0.005). We found a higher probability of presence of LVI and histologic variant in patients with EMVI. EMVI had a sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of 90%, 73%, 94% and 63% respectively in detecting extravesical disease. Our study suggests, EMVI may be a useful biomarker in bladder cancer imaging, is associated with adverse pathology, and could be potentially integrated in the standard of care with regards to MRI reporting systems. A larger study sample size is further warranted to assess feasibility and applicability.

Pericardial Effusion during Proton Therapy in a Patient with Chemorefractory Hodgkin Lymphoma.

We present a case of recurrent pericardial effusion presenting during proton therapy in a 24-year-old female receiving mediastinal treatment for classical Hodgkin lymphoma. Pericardial effusion is typically considered an event accompanying lymphoma diagnosis or as a subacute or late effect of radiotherapy. Rarely has it been described as occurring during radiation treatment with photon-based radiotherapy, let alone proton therapy. It is unclear what underlying cause triggered recurrent effusion in this patient. Identifying and managing pericardial effusion during treatment delivery is important to consider as it may affect radiation dosimetry, particularly with proton therapy. Doing so will help ensure patients receive optimal treatment and minimize the risks of morbidity and mortality.

Diffusion Weighted Imaging in Unilateral Adrenal Infarction: A Case of Colicky Right Upper Quadrant Pain in a Pregnant Female.

Diffusion weighted imaging (DWI) is a magnetic resonance imaging (MRI) non-contrast sequence that can indicate tissue ischemia or infarction. Adrenal infarct may present similarly to biliary or gallbladder pathologies, and the differential diagnosis during emergency work-up can be narrowed utilizing DWI sequences. In this paper, we describe the usefulness of DWI for urgent diagnosis in a case of non-hemorrhagic adrenal infarct of a pregnant female presenting with right upper quadrant pain. Although uncommon, adrenal infarct may occur in patients with hypercoagulability and localizing pain that is unexplained by other imaging modalities. We outline the imaging features of DWI in evaluating adrenal infarct as a safe and time effective application for patients with contraindications to imaging with ionizing radiation.

A Case of Carotid Body Tumor with Perineural Tumor Spread along the Superior Laryngeal Nerve.

We report a case of a patient with a carotid body tumor with perineural tumor spread along the right superior laryngeal nerve. Perineural spread is most commonly associated with squamous cell, adenoid cystic, and mucoepidermoid carcinoma. To the best of our knowledge, this has not been reported previously with carotid body tumor.

It's Not Always Gynecomastia: A Case of Diffuse Large B-Cell Lymphoma Presenting as Breast Mass in a Male Patient.

We report a case of diffuse large B-cell breast lymphoma that presented as a palpable breast lump in a male patient evaluated with digital mammography and targeted breast ultrasound (US) but ultimately confirmed by US-guided core needle biopsy. We will discuss the appropriate workup algorithm for a palpable breast lump in a male patient as outlined by the American College of Radiology (ACR) Appropriateness Criteria. While gynecomastia is the most common reason for a new palpable breast lump in a male patient, male breast cancer (including lymphoma and metastasis) can have a similar appearance on imaging. Our goal is to provide clarity on proper radiographic assessment protocols and imaging features of palpable breast masses in men by emphasizing the role of anatomical location and symmetry in distinguishing it from more common causes, such as gynecomastia, in future diagnostic imaging scenarios.

MRI of myositis and other urgent muscle-related disorders.

Myositis has many etiologies, and it can be encountered in the acute or chronic setting. Our goal is to increase the radiologist's knowledge of myositis and other urgent muscle disorders encountered in the emergent or urgent setting. We review the clinical presentation, the MRI appearance, and the complications that can be associated with these entities. Since myositis can affect multiple muscle compartments, we review how to differentiate the compartments of the appendicular skeletal in order to generate reports that relay important anatomic information to the treating physician. Given the poor sensitivity and positive predictive value of the clinical signs and symptoms used to diagnosing acute compartment syndrome, we discuss the potential use of MRI in cases of suspected but clinically equivocal compartment syndrome in the future.

Radiation-Induced Rib Fractures on Magnetic Resonance Imaging Following Proton Therapy for Breast Cancer With Pencil Beam Scanning.

Radiation-induced rib fractures (RIRF) are long-term complications associated with irradiation of the chest/chest wall. RIRFs are commonly seen in lung- or breast-cancer patients treated with stereotactic body radiotherapy (SBRT) or conventional external beam radiation therapy (EBRT), respectively. We report a case of a 31-year-old female presenting with pathological fractures of the third, fourth, and fifth ribs discovered on magnetic resonance imaging (MRI) as a complication from pencil beam scanning (PBS) proton therapy (PT), of the whole left breast and regional lymph nodes. To our knowledge, this presentation is the first to be initially reported on MRI in radiological literature.

Multimodality Imaging Approach in Evaluation of Post-Traumatic Bronchobiliary Fistulas.

Post-traumatic bronchobiliary fistulas (BBF) are extremely rare with high morbidity and mortality rates. Accurate and timely diagnosis of these entities is critical for appropriate treatment, which usually requires a multidisciplinary approach. We describe two post-traumatic cases using a multimodality approach including computed tomography (CT), magnetic resonance imaging (MRI)/Magnetic Resonance Cholangiopancreatography (MRCP), and hepatobiliary scintigraphy with specific emphasis on the imaging features for each modality. Management of hepatobiliary fistulas is complex, involving extensive diagnostic work up followed by a conservative and/or surgical approach.