Primary Chest Wall Hydatid Disease: A Case Report with Multimodality Imaging Findings.

Primary chest wall hydatid cyst is a very rare disease in endemic areas. This case report describes a 22-year-old male patient with a 3-year history of chronic left chest pain. He had a history of close animal contact in childhood. Chest computed tomography (CT) scan showed a left upper posterior paravertebral cystic mass with peripheral and intrinsic calcifications. Fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET) scan showed no significant FDG uptake. Magnetic resonance imaging (MRI) showed a left paravertebral cystic mass with daughter cysts and a peripheral low T2 wall, compatible with hydatid disease. Medical treatment was started, and a follow-up MRI showed rupture of hydatid cysts. The patient underwent surgical resection, and a hydatid disease diagnosis was confirmed by histopathologic examination. During the postoperative hospital course, the patient developed pneumothorax which was successfully treated with a surgical procedure. The patient was discharged with medical treatment (albendazole). In conclusion, this case highlights the importance of considering hydatid disease in the differential diagnosis of chest wall cystic masses, especially in endemic regions, and the value of multimodality imaging in diagnosis and treatment planning.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: adult cardiac conditions.

BACKGROUND: Medical 3D printing as a component of care for adults with cardiovascular diseases has expanded dramatically. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness criteria for adult cardiac 3D printing indications. METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with a number of adult cardiac indications, physiologic, and pathologic processes. Each study was vetted by the authors and graded according to published guidelines. RESULTS: Evidence-based appropriateness guidelines are provided for the following areas in adult cardiac care; cardiac fundamentals, perioperative and intraoperative care, coronary disease and ischemic heart disease, complications of myocardial infarction, valve disease, cardiac arrhythmias, cardiac neoplasm, cardiac transplant and mechanical circulatory support, heart failure, preventative cardiology, cardiac and pericardial disease and cardiac trauma. CONCLUSIONS: Adoption of common clinical standards regarding appropriate use, information and material management, and quality control are needed to ensure the greatest possible clinical benefit from 3D printing. This consensus guideline document, created by the members of the RSNA 3D printing Special Interest Group, will provide a reference for clinical standards of 3D printing for adult cardiac indications.

Giant cell tumor of bone following denosumab treatment: assessment of tumor response using various imaging modalities.

BACKGROUND: Giant cell tumor (GCT) is a nonmalignant neoplasm composed of multinucleated giant and mononuclear stromal cells. This study aimed to compare imaging findings of GCT pre- and post-denosumab treatment, including lesion size, percentage of signal intensity/density change, and time of initial objective tumor response. This will have a great impact on selection of most appropriate imaging technique to accurately measure therapy response and its related complications, which would influence the physicians to tailor the treatment regimen to suit each patient. RESULTS: As per inverse Choi density/size (ICDS), 16 patients (84.2%) had an objective tumor response and 15 (78.9%) had an increase in density or decrease in signal intensity, and the mean of signal intensity decrease in the treated lesions was 32.4% (95% CI, 18-46.7). Only seven patients (36.8%) had tumors demonstrating ≥ 10% decrease in size, all of which showed a positive change in signal/density except for one. Moreover, 17 patients (89.4%) showed a clear demarcation/low signal intensity margin surrounding ≥ two third of the lesion periphery. The median time to first objective tumor response was approximately 23 weeks. CONCLUSION: Based on the ICDS criteria, most patients with giant cell tumor of bone show objective tumor response to denosumab. Modification of ICDS to include marginal sclerosis or clear demarcation of the lesions might be considered as a separate response criterion to accurately assess the treatment response in patients with GCT.

Geometric inaccuracy and co-registration errors for CT, DynaCT and MRI images used in robotic stereotactic radiosurgery treatment planning.

PURPOSE: To measure the combined errors due to geometric inaccuracy and image co-registration on secondary images (dynamic CT angiography (dCTA), 3D DynaCT angiography (DynaCTA), and magnetic resonance images (MRI)) that are routinely used to aid in target delineation and planning for stereotactic radiosurgery (SRS). METHODS: Three phantoms (one commercial and two in-house built) and two different analysis approaches (commercial and MATLAB based) were used to quantify the magnitude of geometric image distortion and co-registration errors for different imaging modalities within CyberKnife's MultiPlan treatment planning software. For each phantom, the combined errors were reported as a mean target registration error (TRE). The mean TRE's for different intramodality imaging parameters (e.g., mAs, kVp, and phantom set-ups) and for dCTA, DynaCTA, and MRI systems were measured. RESULTS: Only X-ray based imaging can be performed with the commercial phantom, and the mean TRE ± standard deviation values were large compared to the in-house analysis using MATLAB. With the 3D printed phantom, even drastic changes in treatment planning CT imaging protocols did not greatly influence the mean TRE (<0.5 mm for a 1 mm slice thickness CT). For all imaging modalities, the largest mean TRE was found on DynaCT, followed by T2-weighted MR images (albeit all <1 mm). CONCLUSIONS: The user may overestimate the mean TRE if the commercial phantom and MultiPlan were used solely. The 3D printed phantom design is a sensitive and suitable quality assurance tool for measuring 3D geometric inaccuracy and co-registration errors across all imaging modalities.

Applying Modern Virtual and Augmented Reality Technologies to Medical Images and Models.

Recent technological innovations have created new opportunities for the increased adoption of virtual reality (VR) and augmented reality (AR) applications in medicine. While medical applications of VR have historically seen greater adoption from patient-as-user applications, the new era of VR/AR technology has created the conditions for wider adoption of clinician-as-user applications. Historically, adoption to clinical use has been limited in part by the ability of the technology to achieve a sufficient quality of experience. This article reviews the definitions of virtual and augmented reality and briefly covers the history of their development. Currently available options for consumer-level virtual and augmented reality systems are presented, along with a discussion of technical considerations for their adoption in the clinical environment. Finally, a brief review of the literature of medical VR/AR applications is presented prior to introducing a comprehensive conceptual framework for the viewing and manipulation of medical images in virtual and augmented reality. Using this framework, we outline considerations for placing these methods directly into a radiology-based workflow and show how it can be applied to a variety of clinical scenarios.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios.

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Preoperative planning and tracheal stent design in thoracic surgery: a primer for the 2017 Radiological Society of North America (RSNA) hands-on course in 3D printing.

In this work, we provide specific clinical examples to demonstrate basic practical techniques involved in image segmentation, computer-aided design, and 3D printing. A step-by-step approach using United States Food and Drug Administration cleared software is provided to enhance surgical intervention in a patient with a complex superior sulcus tumor. Furthermore, patient-specific device creation is demonstrated using dedicated computer-aided design software. Relevant anatomy for these tasks is obtained from CT Digital Imaging and Communications in Medicine images, leading to the generation of 3D printable files and delivery of these files to a 3D printer.