Evaluation of acute esophageal radiation-induced damage using magnetic resonance imaging: a feasibility study in mice

Background Thoracic and head and neck cancer radiation therapy (RT) can cause damage to nearby healthy organs such as the esophagus, causing acute radiation-induced esophageal damage (ARIED). A non-invasive method to detect and monitor ARIED can facilitate optimizing RT to avoid ARIED while improving local tumor control. Current clinical guidelines are limited to scoring the esophageal damage based on the symptoms of patients. Magnetic resonance imaging (MRI) is a non-invasive imaging modality that may potentially visualize radiation-induced organ damage. We investigated the feasibility of using T2-weighted MRI to detect and monitor ARIED using a two-phased study in mice. Methods The first phase aimed to establish the optimal dose level at which ARIED is inducible and to determine the time points where ARIED is detectable. Twenty four mice received a single dose delivery of 20 and 40 Gy at proximal and distal spots of 10.0 mm (in diameter) on the esophagus. Mice underwent MRI and histopathology analysis with esophageal resection at two, three, and 4 weeks post-irradiation, or earlier in case mice had to be euthanized due to humane endpoints. In the second phase, 32 mice received a 40 Gy single dose and were studied at two, three, and 7 days post-irradiation. We detected ARIED as a change in signal intensity of the MRI images. We measured the width of the hyperintense area around the esophagus in all mice that underwent MRI prior to and after irradiation. We conducted a blind qualitative comparison between MRI findings and histopathology as the gold standard. Results/conclusions A dose of 40 Gy was needed to induce substantial ARIED. MRI detected ARIED as high signal intensity, visible from 2 days post-irradiation. Quantitative MRI analysis showed that the hyperintense area around the esophagus with severe ARIED was 1.41 mm wider than with no damage and MRI-only mice. The overall sensitivity and specificity were 56 and 43% respectively to detect any form of ARIED. However, in this study MRI correctly detected 100% of severe ARIED cases. Our two-phased preclinical study showed that MRI has the potential to detect ARIED as a change in signal intensity and width of enhancement around the esophagus.

A Succession of MRI Scans Supports the Diagnosis of Lumbar Ligamentum Flavum Hematoma: A Case Report and Review of the Literature

Ligamentum flavum hematoma (LFH) is a rare cause of spinal nerve compression. This condition remains challenging to diagnose using MRI due to the changing intensity of the hematoma on imaging. The aim of this study was to describe the patient with LFH who had a succession of MRI scans carried out. We report on a 71-year-old woman with a mass at L4/5 and decompression surgery was performed for her left leg symptom. She had MRI carried out in a previous hospital and also had MRI again in our hospital. In a 2nd MRI of the same area, after a 2-week interval, a newly isointense mass was present within the anterior part of the previously identified lesion on T1-weighted image and the hyperintense area in the lesion was a little extended on T2-weighted imaging. Her symptoms were resolved immediately after decompression surgery. Following a review of previous cases, we suggest that consecutive MRI scanning may support the diagnostic process for LFH.

Pareidolia in Neuroendocrinology: A Pituitary Macroadenoma Resembling “Big Bird”

Context: Pareidolia is the imagined perception of a pattern, where it does not actually exist, as faces. Case Description: A 49-year-old woman presented with a pituitary macroadenoma with supra- and parasellar expansion containing two hypodense areas and one hyperintense area. On the T1W magnetic resonance imaging picture, this macroadenoma closely resembled a famous character from a children's television series. Conclusion: The imaging-phenotype in this case demonstrates that pareidolia can also be observed in neuroendocrinology and neuroradiology.

Animal experimental model of Peyronie’s disease: A pilot study

Objective: The Peyronie's disease (PD) is an idiopathic disorder of connective tissue of the penis, that involves the tunica albuginea of the corpora cavernosa and the adjacent areolar space. It is a growing clinical evidence to support the therapeutic potential of mesenchymal stem cells and histological findings has assumed a possible application of lipofilling technique in patients with PD. The objective of this experimental study is the creation of a murine experimental model of PD, evaluating with MRI the penis of the rats (feasibility study), in order to plane the application of lipofilling technique in an animal model. Methods: Four male Wistar rats were anesthetized, fixed in prone position and subjected to MRI. The animals underwent, subsequently, an injection of thrombin in the tunica albuginea and MRI images were acquired at 7 and 21 days after injection with incision of the dartos. Results: The MRI acquisitions, both in coronal and axial projection, showed an adequate visibility of the anatomical structures. At 7 days after thrombin injection with the dartos incision it was evident an oedematous portion, visible as a hyperintense area, located at the injection area. At 21 days after injection, oedema was partially resolved: the injection part of the hyperintense area remains unchanged, while the remaining area appears to be part of a re-absorption and re-organization process. Conclusions: Since none of the various treatment modalities currently available for the management of PD is able to bring healing, the researchers’ attention is increasingly directed towards innovative treatment programs, such as the use of stem cells of mesenchymal origin. At the present time, the research in PD is hampered by the lack of universally accepted animal model and this is likely attributed to the limited insight into PD mechanisms and the difficulties faced by current animal models to truly represent the complexity.

Cryptogenic Stroke in Hanging

This paper reports the unique neuroimaging findings of a 37-year-old woman who attempted suicide by hanging. To our knowledge, this is the first reported case describing neuroimaging findings of unilateral lesions instead of the well-documented bilateral lesions after a hanging event. Computed tomography demonstrated a low density area in the right thalamus and no hemorrhage. 3.0 T Magnetic resonance revealed a hyperintense area on both T2-weighted and FLAIR images on the right thalamus. Diffusion weighted images demonstrated no area of diffusivity restriction. Another smaller lesion with the same signal characteristics was found in the left cerebellum. A second relevant point of this report is the observation that the most probable cause of the documented unilateral lesions was an ischemic-arterial event.