Technical Note: Histological validation of anatomical imaging for breast modeling using a novel cryo-microtome.

PURPOSE: Precise correlation between three-dimensional (3D) imaging and histology can aid biomechanical modeling of the breast. We develop a framework to register ex vivo images to histology using a novel cryo-fluorescence tomography (CFT) device. METHODS: A formalin-fixed cadaveric breast specimen, including chest wall, was subjected to high-resolution magnetic resonance (MR) imaging. The specimen was then frozen and embedded in an optimal cutting temperature (OCT) compound. The OCT block was placed in a CFT device with an overhead camera and 50 µm thick slices were successively shaved off the block. After each shaving, the block-face was photographed. At select locations including connective/adipose tissue, muscle, skin, and fibroglandular tissue, 20 µm sections were transferred onto cryogenic tape for manual hematoxylin and eosin staining, histological assessment, and image capture. A 3D white-light image was automatically reconstructed from the photographs by aligning fiducial markers embedded in the OCT block. The 3D MR image, 3D white-light image, and photomicrographs were rigidly registered. Target registration errors (TREs) were computed based on 10 pairs of points marked at fibroglandular intersections. The overall MR-histology registration was used to compare the MR intensities at tissue extraction sites with a one-way analysis of variance. RESULTS: The MR image to CFT-captured white-light image registration achieved a mean TRE of 0.73 ± 0.25 mm (less than the 1 mm MR slice resolution). The block-face white-light image and block-face photomicrograph registration showed visually indistinguishable alignment of anatomical structures and tissue boundaries. The MR intensities at the four tissue sites identified from histology differed significantly (p < 0.01). Each tissue pair, except the skin-connective/adipose tissue pair, also had significantly different MR intensities (p < 0.01). CONCLUSIONS: Fine sectioning in a highly controlled imaging/sectioning environment enables accurate registration between the MR image and histology. Statistically significant differences in MR signal intensities between histological tissues are indicators for the specificity of correlation between MRI and histology.

The Physics of Magnetic Resonance Imaging Safety.

Magnetic resonance (MR) imaging relies on a strong static magnetic field in conjunction with careful orchestration of pulsed linear gradient magnetic fields and radiofrequency magnetic fields in order to generate images. The interaction of these fields with patients as well as materials with magnetic or conducting properties can be a source of risk in the MR environment. This article provides a basic review of the physical underpinnings of the primary risks in MR imaging to foster development of intuition with respect to both patient and risk management in the MR environment.

Endoscopic ultrasound-guided inoculation of transmissible venereal tumor in the colon: A large animal model for colon neoplasia.

BACKGROUND: To develop and evaluate the feasibility of emerging interventions, animal models with accurate anatomical environment are required. OBJECTIVES: We aimed to establish a clinically relevant colorectal tumor model with canine transmissible venereal tumor (CTVT) utilizing endoscopic ultrasound (EUS) imaging guidance. DESIGN: Survival study using a canine model. SETTING: Endoscopic animal research laboratory at a tertiary cancer center. MATERIALS AND METHODS: This study involved five canines. INTERVENTIONS: A colorectal tumor model was established and evaluated in five canines under cyclosporine immune suppression. Under endoscopic imaging guidance, saline was injected into the submucosal layer forming a bleb. Subsequently, CTVT was inoculated into the bleb under EUS guidance. Endoscopy was the primary method of assessing tumor growth. Tumors developed in 60-130 days. Upon detection of lesions >1 cm, the animals were euthanized and the tumors were harvested for histopathological characterization. MAIN OUTCOME MEASUREMENTS: Success rate of tumor growth. The presence or absence of vasculature inside tumors. RESULTS: Colorectal tumor successfully developed in three out of the five animals (60%). Among the ones with tumor growth, average inoculated CTVT volume, incubation time, and tumor size was 1.8 cc, 65.7 days, and 2.0 cm, respectively. The two animals without tumor growth were observed for >100 days. In all the tumors, vascular structure was characterized with CD31 imunohistochemical stain. LIMITATIONS: Small number of animals. CONCLUSION: We succeeded in creating a new colorectal tumor canine model with CTVT utilizing EUS.

Image-guided ablation in breast cancer treatment.

In the past 2 decades, new and improved imaging technologies and the use of breast cancer screening have led to the detection of smaller and earlier-stage breast cancers. Furthermore, there has been a trend toward less aggressive treatment of small breast cancers, which has led to the development of less invasive alternatives than surgery with promising effectiveness, and less morbidity. Many patients are not satisfied with the cosmetic outcome after breast-conservation therapy. Better cosmesis can be achieved with less invasive techniques. Moreover, less aggressive treatment options would be very useful in patients older than 70 years with comorbidities that make surgery a difficult and sometimes life-threatening treatment. Minimally invasive ablation techniques have been studied in early-stage small tumors with the goal of attaining efficacy similar to that of breast-conservation therapy. These techniques would have less scarring and pain, lower costs, better preservation of breast tissue, superior cosmesis, and faster recovery time. Breast lesions can be destroyed by thermal methods, that is, by heating or freezing the tissue. There are 5 types of thermal ablations that have been or currently are in research clinical trials: cryoablation, radiofrequency, laser, microwave, and high-intensity focused ultrasound ablation. The first 4 methods destroy cancers using percutaneous image-guided probe placement. High-intensity focused ultrasound is noninvasive, performed without any skin opening.