CT texture analysis can be used to accurately differentiate fp-AML from RCC on unenhanced CT images.

Three-dimensional (3D) printing refers to a number of manufacturing technologies that create physical models from digital information. Radiology is poised to advance the application of 3D printing in health care because our specialty has an established history of acquiring and managing the digital information needed to create such models. The 3D Printing Task Force of the Radiology Research Alliance presents a review of the clinical applications of this burgeoning technology, with a focus on the opportunities for radiology. Topics include uses for treatment planning, medical education, and procedural simulation, as well as patient education. Challenges for creating custom implantable devices including financial and regulatory processes for clinical application are reviewed. Precedent procedures that may translate to this new technology are discussed. The task force identifies research opportunities needed to document the value of 3D printing as it relates to patient care.

The Association of University Radiologists Radiology Research Alliance Task Force on three-dimensional (3D) printing presents a review of the logistic considerations for establishing a clinical service using this new technology, specifically focused on implications for radiology. Specific topics include printer selection for 3D printing, software selection, creating a 3D model for printing, providing a 3D printing service, research directions, and opportunities for radiologists to be involved in 3D printing. A thorough understanding of the technology and its capabilities is necessary as the field of 3D printing continues to grow. Radiologists are in the unique position to guide this emerging technology and its use in the clinical arena.

• Five percent of AML do not demonstrate detectable fat on imaging • These AML are hyperattenuating and T2-hypointense due to abundant smooth muscle • These AML show washout enhancement without association to vessel count at histopathology • Iso-attenuating AML with microscopic fat on MRI show >25% adipocytes/HPF • The term "AML without visible fat" is proposed to reduce ambiguity.

• AMLwvf are difficult to prospectively diagnose with imaging. • MRI findings associated with AMLwvf overlap with various RCC subtypes. • T2W-SI combined with chemical-shift SI-index is specific for AMLwvf but lacks sensitivity. • T2W-SI combined with AUC CE-MRI is sensitive and specific for AMLwvf. • Models incorporating two or more findings are more accurate than univariate analysis.

Coexisting classic angiomyolipomas and the absence of calcification are associated with minimal-fat angiomyolipomas; by contrast, the hypodense rim sign is not useful for diagnosis. Minimal-fat angiomyolipomas have increased absolute and relative (normalized to renal parenchyma) density compared with RCC; however, overlap in density values limit diagnostic utility.

A minority of solid RCCs have attenuation similar to that of water on unenhanced CT. In this study, all such tumors were of the clear cell subtype and qualitatively heterogeneous, suggesting they can be distinguished from simple cysts on unenhanced CT.

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.Electronic supplementary materialThe online version of this article (10.1186/s41205-017-0022-3) contains supplementary material, which is available to authorized users.