SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Radiology

517

 To report radiological findings observed in computed tomography (CT) and magnetic resonance imaging (MRI) scans of the first cases of congenital infection and microcephaly presumably associated with the Zika virus in the current Brazilian epidemic.

Concepts: Case series, Virtopsy, Brain, Radiography, Nuclear magnetic resonance, Magnetic resonance imaging, Radiology, Medical imaging

382

In today’s healthcare climate, Magnetic Resonance Imaging (MRI) is often perceived as a commodity - a service where there are no meaningful differences in quality and thus an area in which patients can be advised to select a provider based on price and convenience alone. If this prevailing view is correct, then a patient should expect to receive the same radiological diagnosis regardless of which imaging center he or she visits or which radiologist reviews the examination. Based on their extensive clinical experience, the authors believe that this assumption is not correct and that it can negatively impact patient care, outcomes and costs.

Concepts: Illness, X-ray, Health care, Health care provider, Nuclear magnetic resonance, Medical imaging, Radiology, Magnetic resonance imaging

324

Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)-which share many visual system properties with humans-can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds' histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task-namely, classification of suspicious mammographic densities (masses)-the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds' successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools.

Concepts: Medical physics, Mammography, X-ray, Image processing, Radiology, Medicine, Cancer, Medical imaging

219

Background Whether brain imaging can identify patients who are most likely to benefit from therapies for acute ischemic stroke and whether endovascular thrombectomy improves clinical outcomes in such patients remains unclear. Methods In this study, we randomly assigned patients within 8 hours after the onset of large-vessel, anterior-circulation strokes to undergo mechanical embolectomy (Merci Retriever or Penumbra System) or receive standard care. All patients underwent pretreatment computed tomography or magnetic resonance imaging of the brain. Randomization was stratified according to whether the patient had a favorable penumbral pattern (substantial salvageable tissue and small infarct core) or a nonpenumbral pattern (large core or small or absent penumbra). We assessed outcomes using the 90-day modified Rankin scale, ranging from 0 (no symptoms) to 6 (dead). Results Among 118 eligible patients, the mean age was 65.5 years, the mean time to enrollment was 5.5 hours, and 58% had a favorable penumbral pattern. Revascularization in the embolectomy group was achieved in 67% of the patients. Ninety-day mortality was 21%, and the rate of symptomatic intracranial hemorrhage was 4%; neither rate differed across groups. Among all patients, mean scores on the modified Rankin scale did not differ between embolectomy and standard care (3.9 vs. 3.9, P=0.99). Embolectomy was not superior to standard care in patients with either a favorable penumbral pattern (mean score, 3.9 vs. 3.4; P=0.23) or a nonpenumbral pattern (mean score, 4.0 vs. 4.4; P=0.32). In the primary analysis of scores on the 90-day modified Rankin scale, there was no interaction between the pretreatment imaging pattern and treatment assignment (P=0.14). Conclusions A favorable penumbral pattern on neuroimaging did not identify patients who would differentially benefit from endovascular therapy for acute ischemic stroke, nor was embolectomy shown to be superior to standard care. (Funded by the National Institute of Neurological Disorders and Stroke; MR RESCUE ClinicalTrials.gov number, NCT00389467 .).

Concepts: Radiology, Embolism, Traumatic brain injury, Modified Rankin Scale, Magnetic resonance imaging, Medical imaging, Brain, Stroke

177

Imaging modalities including magnetic resonance imaging and X-ray computed tomography are established methods in daily clinical diagnosis of human brain. Clinical equipment does not provide sufficient spatial resolution to obtain morphological information on the cellular level, essential for applying minimally or non-invasive surgical interventions. Therefore, generic data with lateral sub-micrometer resolution have been generated from histological slices post mortem. Sub-cellular spatial resolution, lost in the third dimension as a result of sectioning, is obtained using magnetic resonance microscopy and micro computed tomography. We demonstrate that for human cerebellum grating-based X-ray phase tomography shows complementary contrast to magnetic resonance microscopy and histology. In this study, the contrast-to-noise values of magnetic resonance microscopy and phase tomography were comparable whereas the spatial resolution in phase tomography is an order of magnitude better. The registered data with their complementary information permit the distinct segmentation of tissues within the human cerebellum.

Concepts: Medicine, Cerebellum, Radiology, Virtopsy, Brain, Radiography, Magnetic resonance imaging, Medical imaging

172

Image-guided endovascular interventions have gained increasing popularity in clinical practice, and magnetic resonance imaging (MRI) is emerging as an attractive alternative to X-ray fluoroscopy for guiding such interventions. Steering catheters by remote control under MRI guidance offers unique challenges and opportunities.

Concepts: Artificial pacemaker, Angiography, Nuclear magnetic resonance, Radiography, X-ray, Radiology, Medical imaging, Magnetic resonance imaging

170

A 46-year old male patient was admitted with a history of an extremely painful right upper arm, associated with unilateral clubbing. Duplex scanning and magnetic resonance imaging were suggestive of a pseudo-aneurysm of the brachial artery. Digital angiography showed an irregular brachial artery, associated with a small pseudo-aneurysm. The brachial artery was partially resected and reconstructed with a venous interposition graft. Pathological examination provided the final diagnosis of fibromuscular dysplasia. Although more encountered in women, this case report describes the occurrence of fibromuscular dysplasia in an unusual location in a male patient with a long-term follow-up.

Concepts: Humerus, Brachial plexus, X-ray, Radiology, Nuclear magnetic resonance, Medical imaging, Magnetic resonance imaging, Blood pressure

170

Transcatheter arterial chemoembolization (TACE) is the most widely used treatment option for unresectable hepatocellular carcinoma (HCC). Elevated serum YKL-40 level has been shown to predict poor prognosis in HCC patients undergoing resection. This study was designed to validate the prognostic significance of serum YKL-40 in patients with HCC undergoing TACE treatment.

Concepts: Prognosis, Medical terms, Radiology, Thought experiment, Lung cancer, Hepatology, Hepatocellular carcinoma, Transcatheter arterial chemoembolization

168

Purpose: Imaging features and clinical characteristics of degenerated leiomyoma in patients referred for uterine fibroid embolization (UFE) were analyzed to assess the incidence of degenerated leiomyoma. Materials and Methods: Patients referred for UFE between 2008 and 2009 were retrospectively analyzed (n=276). Patients ranged in age from 27 to 51 years (mean 38.0 years). All patients underwent screening MRI with contrast enhancement. Medical histories and clinical symptoms were evaluated. Results: Among the 276 patients who underwent MRI, 14 (5.1%) showed degenerated leiomyomas. Symptoms were abdominal pain (n=4, 26.7%), menorrhagia (n=5, 35.7%) and bulk-related symptoms (n=5, 35.7%) and no symptoms (n=5, 35.7%). Of the 14 patients with degenerated leiomyomas, 5 (42.9%) had a history of pregnancy in the past two years. For T1-weighted imaging (T1WI), a high signal intensity (SI) of the leiomyoma was the most common finding (n=9, 64.3%) and a hyperintense rim (n=4, 28.6%) was the second most common. On T2-weighted imaging (T2WI), a low SI of the leiomyoma was found in six patients (42.9%), a high SI in four (28.6%) and a heterogeneous SI in four (28.6%) patients. Conservative management was performed in 11 (78.6%) patients, surgery in 3 (21.4%) and uterine artery embolization in one (7.1%) patient. Conclusion: The incidence of degeneration of leiomyoma in patients referred for UFE was 5.1%. Patients presented with variable clinical symptoms with or without a history of pregnancy. MR imaging showed a high SI on T1WI and various SIs on T2WI without contrast enhancement. An understanding of the degeneration of leiomyomata is essential when considering UFE.

Concepts: Leiomyoma, Myometrium, Anatomical pathology, Gynecology, Radiology, Uterus, Uterine fibroids, Uterine artery embolization

168

Fever of unknown origin is a diagnostic challenge. Among its causes are of large caliber vessels vasculitis (LCVV), including Takayasu arteritis (TA) and giant cell arteritis (GCA). Early diagnosis is vital to prevent fibrosis of the vessel wall, and consequently, stenoses, aneurysms or occlusions. Imaging techniques can be of great help in recent years, highlighting the temporal artery through ultrasound, MRI and PET-CT.

Concepts: Arteritis, Blood vessel, Positron, Takayasu's arteritis, Radiology, Giant cell arteritis, Positron emission tomography, Medical imaging