Acute ischaemic stroke associated with SARS-CoV-2 infection in North America.

BACKGROUND: To analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome. METHODS: Multicentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications. RESULTS: A total of 216 COVID-19 patients with AIS were included. 68.1% (147/216) were older than 60 years, while 31.9% (69/216) were younger. Median [IQR] National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.5 (15.8), and 44.2% (87/197) presented with large vessel occlusion (LVO). Approximately 51.3% (98/191) of the patients had poor outcomes with an observed mortality rate of 39.1% (81/207). Age >60 years (aOR: 5.11, 95% CI 2.08 to 12.56, p<0.001), diabetes mellitus (aOR: 2.66, 95% CI 1.16 to 6.09, p=0.021), higher NIHSS at admission (aOR: 1.08, 95% CI 1.02 to 1.14, p=0.006), LVO (aOR: 2.45, 95% CI 1.04 to 5.78, p=0.042), and higher NLR level (aOR: 1.06, 95% CI 1.01 to 1.11, p=0.028) were significantly associated with poor functional outcome. CONCLUSION: There is relationship between COVID-19-associated AIS and severe disability or death. We identified several factors which predict worse outcomes, and these outcomes were more frequent compared to global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-Dimer, predicted both morbidity and mortality.

Immediate Allergic Reactions to Gadolinium-based Contrast Agents: A Systematic Review and Meta-Analysis.

Purpose To perform a systematic review and meta-analysis to determine if there are differences in rates of immediate allergic events between classes of gadolinium-based contrast agents (GBCAs). Materials and Methods PubMed and Google Scholar databases were searched for studies in which rates of immediate adverse events to GBCAs were reported. The American College of Radiology classification system was used to characterize allergic-like events as mild, moderate, or severe, and the total number of administrations of each GBCA was recorded. Where necessary, authors of studies were contacted to clarify data and eliminate physiologic reactions. Relative risks of GBCA types were estimated by using the Mantel-Haenszel type method. Results Nine studies in which immediate reactions to GBCA were recorded from a total of 716 978 administrations of GBCA met the criteria for inclusion and exclusion. The overall rate of patients who had immediate allergic-like reactions was 9.2 per 10 000 administrations and the overall rate of severe immediate allergic-like reactions was 0.52 per 10 000 administrations.. The nonionic linear chelate gadodiamide had the lowest rate of reactions, at 1.5 (95% confidence interval [CI]: 0.74, 2.4) per 10 000 administrations, which was significantly less than that of linear ionic GBCAs at 8.3 (95% CI: 7.5, 9.2) per 10 000 administrations (relative risk, 0.19 [95% CI: 0.099, 0.36]; P < .00001) and less than that for nonionic macrocyclic GBCAs at 16 (95% CI: 14, 19) per 10 000 administrations (relative risk, 0.12 [95% CI: 0.05, 0.31]; P < .001). GBCAs known to be associated with protein binding had a higher rate of reactions, at 17 (95% CI: 15, 20) per 10 000 administrations compared with the same chelate classification without protein binding, at 5.2 (95% CI: 4.5, 6.0) per 10 000 administrations (relative risk, 3.1 [95% CI: 2.4, 3.8]; P < .0001). Conclusion These data show the lowest rate of immediate allergic adverse events with use of the nonionic linear GBCA gadodiamide in comparison with those of ionic linear or nonionic macrocyclic GBCAs. A higher rate of immediate allergic adverse events was associated with ionicity, protein binding, and macrocyclic structure. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on August 31, 2017.

Dentate Nucleus Signal Intensity Decrease on T1-weighted MR Images after Switching from Gadopentetate Dimeglumine to Gadobutrol.

Purpose To determine if the increased dentate nucleus signal intensity following six or more doses of a linear gadolinium-based contrast agent (GBCA) (gadopentetate dimeglumine) changes at follow-up examinations performed with a macrocyclic GBCA (gadobutrol). Materials and Methods This retrospective study included 13 patients with increased dentate nucleus signal intensity following at least six (range, 6-18) gadopentetate dimeglumine administrations who then underwent at least 12 months of follow-up imaging with multiple (range, 3-29) gadobutrol-enhanced magnetic resonance (MR) examinations. Dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios were measured by two radiologists blinded to all patient information, and changes were analyzed by using the paired t test and linear regression. Results The mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios increased after gadopentetate dimeglumine administration, from 0.98 ± 0.03 to 1.10 ± 0.03 (P < .0001) and from 0.98 ± 0.030 to 1.09 ± 0.02 (P < .0001), respectively. With gadobutrol, the mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios decreased to 1.03 ± 0.03 and 1.02 ± 0.04, respectively (P < .0001). With use of a mixed effects model linear regression allowing for each patient to have a different y intercept, mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios decreased with follow-up time (dentate nucleus-to-pons: slope = -0.2% per month [95% confidence interval: -0.0024, -0.0015], R2 = 0.58, P < .0001 for nonzero slope; dentate nucleus-to-cerebellar peduncle: slope = -0.2% per month [95% confidence interval: -0.0024, -0.0015], R2 = 0.61, P < .0001 for nonzero slope). Conclusion Dentate signal intensity increased with at least six gadopentetate dimeglumine-enhanced MR examinations and decreased after switching from a linear (gadopentetate dimeglumine) to a macrocyclic (gadobutrol) GBCA. © RSNA, 2018 Online supplemental material is available for this article.

Automating Perforator Flap MRA and CTA Reporting.

Surgical breast reconstruction after mastectomy requires precise perforator coordinates/dimensions, perforator course, and fat volume in a radiology report. Automatic perforator reporting software was implemented as an OsiriX Digital Imaging and Communications in Medicine (DICOM) viewer plugin. For perforator analysis, the user identifies a reference point (e.g., umbilicus) and marks each perforating artery/vein bundle with multiple region of interest (ROI) points along its course beginning at the muscle-fat interface. Computations using these points and analysis of image data produce content for the report. Post-processing times were compared against conventional/manual methods using de-identified images of 26 patients with surgically confirmed accuracy of perforator locations and caliber. The time from loading source images to completion of report was measured. Significance of differences in mean processing times for this automated approach versus the conventional/manual approach was assessed using a paired t test. The mean conventional reporting time for our radiologists was 76 ± 27 min (median 65 min) compared with 25 ± 6 min (median 25 min) using our OsiriX plugin (p < 0.01). The conventional approach had three reports with transcription errors compared to none with the OsiriX plugin. Otherwise, the reports were similar. In conclusion, automated reporting of perforator magnetic resonance angiography (MRA) studies is faster compared with the standard, manual approach, and transcription errors which are eliminated.

Varicocele Embolization Following Failure Of Varicocelectomy: A Case Series And Review Of Literature.

Varicocelectomy remains the same mainstay of treatment for varicoceles. However, with growing focus on minimally invasive techniques, recent literature has investigated the use of venous embolization for the treatment of varicoceles in patients with recurrence after surgical treatment. Embolization has many advantages, including use of local anaesthesia, lower operating time, decreased risk of hydrocele and faster recovery times. In addition to this direct visualization of the vasculature during embolization allows for identification of any anatomic variants or collateral vessel accounting for the recurrence. This permits more definitive treatment in case of prior surgical failure. We present a case series where venous embolization is successfully done following failure of varicocelectomy. For patients who experience recurrence after a varicocelectomy, we recommend consideration for varicocele embolization.

Lectures in medical educaton: what students think?

BACKGROUND: The volume of medical knowledge has increased exponentially and so has the need to improve the efficiency of current teaching practices.With increasing emphasis on interactive and problem based learning, the place of lectures in modern medical education has become a questionable issue. Objectives were to assess the perspective of undergraduate medical students regarding the role and effectiveness of lectures as a mode of instruction as well as the ways and means that can be employed to enhance the effectiveness of lectures. METHODS: A cross sectional study was carried out among 2nd to final year medical students from five medical colleges including both private and public sector institutions. A total of 347 students participated by completing a structured questionnaire. Data was analyzed using SPSS-17. RESULTS: Sixty seven percent students considered lectures as a useful mode of instruction (47% males and 77% females), whereas 83% of the students reported that clinical sessions were superior to lectures because of small number of students in clinical sessions, active student participation, enhanced clinical orientation, and interaction with patients. About 64% responded that lectures should be replaced by clinical sessions. Majority of the students (92%) reported not being able to concentrate during a lecture beyond 30 minutes, whereas 70% skipped lectures as they were boring. A significantly greater proportion of male respondents, students from clinical years, and those who skipped lectures, considered lectures to be boring, a poor utilization of time and resources, and could not concentrate for the full duration of a lecture compared to females, students from preclinical years, and those who do not skip lectures, respectively. CONCLUSION: Lecturing techniques need to be improvised. The traditional passive mode of instruction has to be replaced with active learning and inquiry based approach to adequately utilize the time and resources spent on lectures.

Bedside manners: do we care?

BACKGROUND: Teaching bedside manner might prove to be one of the most challenging tasks in medical education as it is not easy to structure or formalise such training. Besides, the rigorous training process for acquiring clinical and technical skills often overshadows the humanistic aspect of medical care. The aim of this study was to assess the perception of final year medical students as well as the faculty regarding the teaching and practice of bedside manner including a brief evaluation of students' bedside manner. METHODS: A cross-sectional study was conducted involving final year medical students from five medical colleges (n = 193) and faculty from a single institution (n=29). Sample was selected using systematic random or convenient sampling techniques. Data was collected using self administered, anonymous, structured questionnaire. Data were analysed using SPSS-17. RESULTS: While evaluating students' bedside manner, 85% of the students reported they always take consent while interacting with a patient whereas, only 17% of the faculty members agreed with this. Only 3% of the faculty members reported that students take care of privacy of patients and none of them thought that students reassure a patient during an encounter whereas the percentages among students were 76% and 48%, respectively. Though students thought they need to improve, majority (56%) of them was confident of their bedside manner. On the other hand, 83% of the faculty members rated students' bedside manner from fair to poor. A large proportion (69%) of the faculty members were not satisfied with the quality of teaching regarding bedside manner, reporting lack of focus on this particular aspect of medical care as the most important cause. Majority of the students (87%) believed doctors have a better bedside manner in private as compared to public hospitals. CONCLUSION: Students have an inflated evaluation of their bedside manner but majority felt a need to improve. A sharp contrast exists between students' and faculty's opinion regarding the practice of bedside manner by students. An outright lack of focus on bedside manner was reported as the most important cause for inadequate emphasis on teaching this particular aspect of medical care.

Erdheim-Chester Disease With Concurrent Lung Adenocarcinoma.

Erdheim-Chester disease (ECD) is a rare type of blood cancer characterized by infiltration of the body tissues by pathologic histiocytes, leading to widespread inflammation and damage. Clinical presentations range widely, from asymptomatic infiltration of bone to multiple organ system damage and resultant dysfunction. This report describes a case of a patient with several unusual imaging findings that led to a differential diagnosis of ECD; however, a biopsy of a mediastinal mass suspected to be due to histiocyte infiltration instead revealed primary lung cancer. Ultimately, ECD could not be ruled out, and the patient was referred to dermatology for a superficial facial xanthelasma biopsy, results of which were consistent with ECD. Concurrent ECD and adenocarcinoma is highly unusual; this case demonstrates the importance of a thorough investigation and the consideration that not all findings may be attributable to a single disease process, even when the alternative is very unlikely.

A Review of Perceptual Expertise in Radiology-How it develops, How we can test it, and Why humans still matter in the era of Artificial Intelligence.

As the first step in image interpretation is detection, an error in perception can prematurely end the diagnostic process leading to missed diagnoses. Because perceptual errors of this sort-"failure to detect"-are the most common interpretive error (and cause of litigation) in radiology, understanding the nature of perceptual expertise is essential in decreasing radiology's long-standing error rates. In this article, we review what constitutes a perceptual error, the existing models of radiologic image perception, the development of perceptual expertise and how it can be tested, perceptual learning methods in training radiologists, and why understanding perceptual expertise is still relevant in the era of artificial intelligence. Adding targeted interventions, such as perceptual learning, to existing teaching practices, has the potential to enhance expertise and reduce medical error.

Comparison of MRI segmentation techniques for measuring liver cyst volumes in autosomal dominant polycystic kidney disease.

PURPOSE: To compare MRI segmentation methods for measuring liver cyst volumes in autosomal dominant polycystic kidney disease (ADPKD). METHODS: Liver cyst volumes in 42 ADPKD patients were measured using region growing, thresholding and cyst diameter techniques. Manual segmentation was the reference standard. RESULTS: Root mean square deviation was 113, 155, and 500 for cyst diameter, thresholding and region growing respectively. Thresholding error for cyst volumes below 500ml was 550% vs 17% for cyst volumes above 500ml (p<0.001). CONCLUSION: For measuring volume of a small number of cysts, cyst diameter and manual segmentation methods are recommended. For severe disease with numerous, large hepatic cysts, thresholding is an acceptable alternative.

Avoiding the Trap of Misdiagnosis: Valuable Teaching Points Derived from a Case of Longstanding Popliteal Artery Entrapment Syndrome.

Popliteal artery entrapment syndrome (PAES), a condition predominantly affecting young individuals, is a rare clinical entity that can result in significant morbidity. The presence of lower limb pain and claudication in young, physically active individuals should prompt consideration for PAES. Early diagnosis and management is crucial to prevent long-term complications; however, diagnosis is fraught with challenges due to the rarity of the disease and its similar clinical presentation with more common conditions. We present a case of a young female with PAES who was misdiagnosed and underwent a tarsal tunnel release for suspected tarsal tunnel syndrome and subsequent fasciotomies for presumed chronic exertional compartment syndrome (CECS) without any relief. We outline the insidious undiagnosed course of her condition over a period of 12 years, discuss teaching points of how to recognize key differences of PAES and associated conditions, and provide recommendations for how to make the right diagnosis.

MRI and CT contrast media extravasation: A systematic review.

BACKGROUND: This systematic review combines data from multiple papers on contrast media extravasation to identify factors contributing to increased extravasation risk. METHODS: Data were extracted from 17 papers reporting 2191 extravasations in 1,104,872 patients (0.2%) undergoing computed tomography (CT) or magnetic resonance imaging (MRI). RESULTS: Extravasation rates were 0.045% for gadolinium-based contrast agents (GBCA) and nearly 6-fold higher, 0.26% for iodinated contrast agents. Factors associated with increased contrast media extravasations included: older age, female gender, using an existing intravenous (IV) instead of placing a new IV in radiology, in-patient status, use of automated power injection, high injection rates, catheter location, and failing to warm up the more viscous contrast media to body temperature. CONCLUSION: Contrast media extravasation is infrequent but nearly 6 times less frequent with GBCA for MRI compared with iodinated contrast used in CT.

Complex liver cysts in Autosomal Dominant Polycystic Kidney Disease.

PURPOSE: To determine prevalence of complex liver cysts in Autosomal Dominant Polycystic Kidney Disease (ADPKD). METHODS: Abdominal MRI in 186 ADPKD subjects were evaluated by two independent observers to determine prevalence of complex liver cysts. RESULTS: 23 (12%) of subjects, had at least 1 complex cyst. Only 8 (4%) were reported to have a complex cyst prospectively, representing an under-reporting rate of 65%. Median total cyst volume was 66-times greater for subjects with complex cysts compared to subjects without (p<0.0001). CONCLUSION: Complex hepatic cysts were observed in 12% of ADPKD cases, occurring more frequently in livers with extensive cystic involvement.

Clinical case report: discitis osteomyelitis complicated by inferior vena cava venous thrombosis and septic pulmonary emboli.

Viridans group streptococcus is an infrequent cause of osteomyelitis that is found in association with infective endocarditis. Only a few studies report viridans osteomyelitis in the absence of endocarditis. Vertebral pyogenic osteomyelitis can sometimes be complicated by psoas or paraspinal abscesses. These intra-abdominal and/or pelvic collections can very rarely result in venous thrombosis. A paraspinal abscess resulting in inferior vena cava (IVC) thrombosis has only been reported once in the literature. We report a case of a young female with a history of polysubstance abuse and chronic back pain, who was found to have extensive vertebral osteomyelitis and discitis with epidural, paraspinal, and psoas abscesses caused by viridans streptococci. These abscesses compressed on the IVC causing IVC thrombophlebitis extending to the iliac veins distally. Imaging also demonstrated multifocal bilateral septic pulmonary emboli and pleural effusions secondary to septic IVC thrombus; a transesophageal echocardiogram showed no evidence of infective endocarditis.

Tongue base schwannoma: differential diagnosis and imaging features with a case presentation.

Schwannomas are slow growing, encapsulated neoplasms that arise from the nerve sheath. A vast majority of these benign neoplasms occur in the head and neck region, most commonly involving the 8th cranial nerve. Schwannomas arising from the base of tongue are very rare and, thus, can easily escape the list of differential diagnosis for a posterior tongue mass. A systematic approach is recommended for diagnosis of a posterior tongue mass, with neoplastic, infectious, and congenital categories. We report a case of a 24-year-old female, who presented with pressure sensation in the throat. On imaging, she was found to have a mass in the right posterior tongue with follow-up biopsy results yielding a schwannoma. Characteristic imaging features for various possible etiologies of a posterior tongue mass are also discussed.

Recurrent solitary fibrous tumor of lumbar spine with vertebral body involvement: imaging features and differential diagnosis with report of a case.

Solitary fibrous tumors (SFTs) of the spine are exceedingly rare tumors of mesenchymal origin. Most spinal SFTs arise from the thoracic spine, followed by cervical spine, and last lumbar spine with only 6 cases reported in literature. SFTs represent a wide range of neoplasms, ranging from benign to malignant. These tumors can develop a late recurrence, even after a decade or more of initial presentation, requiring long-term follow-up. We present a case of recurrent SFT of the lumbar spine with vertebral body involvement, presenting more than a decade after initial resection. It was initially misdiagnosed as a paraganglioma. To the best of our knowledge, there have been only 3 previous cases reporting SFT with vertebral body involvement.