Canadian Association of Radiologists Cardiovascular Imaging Referral Guideline.

The Canadian Association of Radiologists (CAR) Cardiovascular Expert Panel is made up of physicians from the disciplines of radiology, cardiology, and emergency medicine, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 30 clinical/diagnostic scenarios, a rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 48 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 125 recommendation statements across the 30 scenarios (27 unique scenarios as 2 scenarios point to the CAR Thoracic Diagnostic Imaging Referral Guideline and the acute pericarditis subscenario is included under 2 main scenarios). This guideline presents the methods of development and the referral recommendations for acute chest pain syndromes, chronic chest pain, cardiovascular screening and risk stratification, pericardial syndromes, intracardiac/pericardial mass, suspected valvular disease cardiomyopathy, aorta, venous thrombosis, and peripheral vascular disease.

An Update on Acute Mesenteric Ischemia.

Acute mesenteric ischemia (AMI) is an uncommon yet highly lethal cause of acute abdomen in the emergency setting. Computed tomography (CT) imaging, in particular a biphasic protocol consisting of angiographic and venous phase scans, is widely used to corroborate non-specific clinical findings when suspicions of AMI are high. Techniques such as low kilovoltage peak scanning, dual energy acquisition, or a combined arterial/enteric phase can improve iodine conspicuity and evaluation of bowel enhancement. Biphasic CT with CT angiography is mandatory to directly assess for the 3 primary etiologies of AMI-arterial, venous, and non-occlusive mesenteric ischemia (NOMI), and the CT angiographic findings may be the first visible in the disease. In addition, numerous non-vascular CT findings have also been reported. Bowel wall thickening, mesenteric stranding, and ascites are common but non-specific findings that correlate poorly with disease severity. Pneumatosis intestinalis and portomesenteric venous gas, while not pathognomonic for ischemia, are highly specific in cases of high clinical suspicion. Bowel wall hypoenhancement is an early and specific sign but requires a protocol optimizing iodine conspicuity to confidently identify. Finally, intraperitoneal free air and solid organ infarcts are also highly specific ancillary findings in AMI. AMI occurs as a complication in 10% of small bowel obstruction (SBO) patients, and understanding imaging findings of ischemia in the context of SBO is necessary to aid in treatment planning and reduce over- and under-diagnosis of strangulation. Familiarity with the imaging features of ischemia by radiologists is vital to establish an early diagnosis before irreversible necrosis occurs.

Recommendations for the Management of Incidental Musculoskeletal Findings on MRI and CT.

The Canadian Association of Radiologists (CAR) Incidental Findings Working Group consists of both academic subspeciality and general radiologists tasked with either adapting American College of Radiology (ACR) guidelines to meet the needs of Canadian radiologists or authoring new guidelines where appropriate. In this case, entirely new guidelines to deal with incidental musculoskeletal findings that may be encountered on thoracoabdominal computed tomography or magnetic resonance imaging were drafted, focussing on which findings should prompt recommendations for further workup. These recommendations discuss how to deal with incidental marrow changes, focal bone lesions, abnormalities of the pubic symphysis and sacroiliac joints, fatty soft tissue masses, manifestations of renal osteodystrophy and finally discuss opportunistic osteoporosis evaluation.

Emergency Radiology: Evolution, Current Status, and Future Directions.

Emergency Radiology is a clinical practice and an academic discipline that has rapidly gained increasing global recognition among radiology and emergency/critical care departments and trauma services around the world. As with other subspecialties, Emergency Radiology practice has a unique scope and purpose and presents with its own unique challenges. There are several advantages of having a dedicated Emergency Radiology section, perhaps most important of which is the broad clinical skillset that Emergency Radiologists are known for. This multi-society paper, representing the views of Emergency Radiology societies in Canada and Europe, outlines several value-oriented contributions of Emergency Radiologists and briefly discusses the current state of Emergency Radiology as a subspecialty.

Recommendations for the Management of Incidental Pancreatic Findings in Adults by the Canadian Association of Radiologists Incidental Findings Working Group.

The Canadian Association of Radiologists Incidental Findings Working Group consists of both academic subspecialty and general radiologists and is tasked with adapting and expanding upon the American College of Radiology incidental findings white papers to more closely apply to Canadian practice patterns, particularly more comprehensively dealing with the role of ultrasound and pursuing more cost-effective approaches to the workup of incidental findings without compromising patient care. Presented here are the 2021 Canadian guidelines for the management of pancreatic incidental findings. Topics covered include anatomic variants, fatty atrophy, pancreatic calcifications, ductal ectasia, and management of incidental pancreatic cysts.

Canadian Association of Radiologists Prostate MRI White Paper.

Prostate cancer is the most common malignancy and the third most common cause of death in Canadian men. In light of evolving diagnostic pathways for prostate cancer and the increased use of MRI, which now includes its use in men prior to biopsy, the Canadian Association of Radiologists established a Prostate MRI Working Group to produce a white paper to provide recommendations on establishing and maintaining a Prostate MRI Programme in the context of the Canadian healthcare system. The recommendations, which are based on available scientific evidence and/or expert consensus, are intended to maintain quality in image acquisition, interpretation, reporting and targeted biopsy to ensure optimal patient care. The paper covers technique, reporting, quality assurance and targeted biopsy considerations and includes appendices detailing suggested reporting templates, quality assessment tools and sample image acquisition protocols relevant to the Canadian healthcare context.

Canadian Association of Radiologists Guidance on Contrast Associated Acute Kidney Injury.

Iodinated contrast media (ICM) is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after ICM administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations. This revised guidance document was developed by a multidisciplinary CAR Working Group of radiologists and nephrologists, and summarizes changes in practice related to contrast administration, screening, and risk stratification since the last guideline. It reviews the scientific evidence for contrast associated AKI and provides consensus-based recommendations for its prevention and management in the Canadian healthcare context. This article is a joint publication in the Canadian Association of Radiologists Journal and Canadian Journal of Kidney Health and Disease, intended to inform both communities of practice.

Scleraxis as a prognostic marker of myocardial fibrosis in hypertrophic cardiomyopathy (SPARC) study.

Interstitial fibrosis is a histopathological hallmark of hypertrophic cardiomyopathy (HCM). Although extracellular matrix (ECM) biomarkers, including matrix metalloproteinases, are overexpressed in HCM patients, they do not correlate with sudden cardiac death (SCD) risk. The objective of this study was to determine whether scleraxis, a transcription factor that regulates collagen gene expression, is detectable in HCM patients and correlates with disease burden. Between 2017 and 2018, a total of 46 HCM patients were enrolled (58 ± 14 years (31 males, 15 females)) with a mean 5 year SCD risk of 2.3% ± 1.3%. Cardiac MRI confirmed HCM in all patients with a mean interventricular septal thickness of 20 ± 2 mm. Late gadolinium enhancement (LGE) was present in 32 (70%) study participants occupying 18% ± 7% of the left ventricular (LV) myocardium. Serum scleraxis levels were significantly higher in the HCM patients by approximately twofold as compared to controls (0.76 ± 0.06 versus 0.32 ± 0.02 ng/mL, p < 0.05). No correlation was demonstrated between serum scleraxis levels and markers of disease severity in HCM patients, including maximum LV wall thickness, %LGE, and SCD risk factors. Serum scleraxis is elevated in the HCM population. Future studies are warranted to evaluate the prognostic value of scleraxis in identifying high-risk HCM patients who require aggressive management for prevention of SCD.

Recommendations for the Management of Incidental Hepatobiliary Findings in Adults: Endorsement and Adaptation of the 2017 and 2013 ACR Incidental Findings Committee White Papers by the Canadian Association of Radiologists Incidental Findings Working Group.

The Canadian Association of Radiologists Incidental Findings Working Group consists of both academic subspecialty and general radiologists and is tasked with adapting and expanding upon the American College of Radiology incidental findings white papers to more closely apply to Canadian practice patterns, particularly more comprehensively dealing with the role of ultrasound and pursuing more cost-effective approaches to the workup of incidental findings without compromising patient care. Presented here are the 2020 Canadian guidelines for the management of hepatobiliary incidental findings. Topics covered include initial assessment of hepatic steatosis and cirrhosis, the workup of incidental liver masses identified on ultrasound and computed tomography (with algorithms presented), incidental gallbladder findings (wall thickening, calcification, and polyps), and management of incidental biliary dilatation.

In vivo 1 H MRS of human gallbladder bile in understanding the pathophysiology of primary sclerosing cholangitis (PSC): Immune-mediated disease versus bile acid-induced injury.

Primary sclerosing cholangitis (PSC) has been considered to be either an "autoimmune disease" or a "bile acid-induced injury." In vitro MRS studies on PSC patients have limitations due to the contamination of bile with contrast agent (commonly administered during endoscopic retrograde cholangiopancreatography) and/or the use of patient cohorts with other diseases as controls. The objective of this study was to quantify biliary metabolites using in vivo 1 H MRS and gain insight into the pathogenesis of PSC. Biliary metabolites in 10 PSC patients and 14 healthy controls were quantified in vivo using 1 H MRS on a 3 T MR scanner. The concentrations of total bile acids plus cholesterol, glycine-conjugated bile acids, taurine-conjugated bile acids, and choline-containing phospholipids (chol-PLs) were compared between the two groups. There were statistically significant decreases in the levels of the above mentioned biliary metabolites in the PSC patients compared with controls. The reduction in bile acid secretion in bile of PSC patients indicates accumulation of bile acids in hepatocytes. Moreover, reduction in the levels of chol-PLs in bile may increase the toxic effects of bile acids. Our findings suggest that the bile duct injury in PSC patients is most likely due to "bile acid-induced injury."

Long-Term Surveillance of Complex Cystic Renal Masses and Heterogeneity of Bosniak 3 Lesions.

PURPOSE: We sought to better characterize the frequency of Bosniak cyst class changes, identify predictors of change and progression, determine the average growth rate of cysts and validate the safety of active surveillance. MATERIALS AND METHODS: Consecutive patients referred for the management of complex cysts (Bosniak 2F or greater) were included in analysis. All imaging studies were reevaluated and any stage change was reviewed with a blinded genitourinary radiologist. Bosniak 3 cysts were subclassified as 3s-septated enhancing Bosniak cysts and 3n-cysts with wall or septation-only nodularity. A multivariate Cox proportional hazards model was used to identify predictors of the Bosniak classification change. Kaplan-Meier curves were applied to analyze Bosniak cyst progression and regression. RESULTS: A total 140 lesions were included in study, necessitating review of a total of 1,011 abdominal scans in 111 patients. Median followup was 46 months (IQR 23-65.5) and patients underwent a mean of 6.8 diagnostic scans. On multivariate analysis nodular cysts progressed (HR 6.16, 95% CI 2.58-14.72, p <0.00004) and entirely endophytic cysts were less likely to progress (HR 0.21, 95% CI 0.05-0.85, p = 0.028). On Kaplan-Meier analysis Bosniak 3s cysts were more likely to regress while Bosniak 3n cysts were more likely to progress than 3s cysts (p = 0.0178 and 0.0002, respectively). The growth rate of 3n and 2F cysts was 0.19 and 0.11 cm per year (p = 0.0493 and 0.0327, respectively). Locally advanced or metastatic disease did not develop in any patient. CONCLUSIONS: A diagnostic change in Bosniak 3s and 2F cysts is common and Bosniak 3n cysts behave more like Bosniak 4 cysts. Most complex kidney cysts can be safely monitored without intervention and the interval between serial imaging procedures should be increased.

MRI evaluation of maternal cardiac displacement in pregnancy: implications for cardiopulmonary resuscitation.

OBJECTIVE: The purpose of this study was to determine, with the use of cardiac magnetic resonance imaging, whether there is vertical displacement of the heart during pregnancy. Cardiopulmonary resuscitation guidelines during pregnancy recommend placing the hands 2-3 cm higher on the sternum than in nonpregnant individuals. This recommendation is based on the presumption that the heart is displaced superiorly by the diaphragm during the third trimester. Whether there is true cardiac displacement because of the expanding uterus in pregnancy remains unknown. STUDY DESIGN: A total of 34 healthy female volunteers 18-35 years old were enrolled prospectively from 2010-2012 at 2 tertiary care centers. The conditions of all participants were evaluated with cardiac magnetic resonance imaging in the one-half left lateral decubitus position during the third trimester of pregnancy and again at a minimum of 3 months after delivery (surrogate for the nonpregnant state). Superior displacement of the heart was determined by measurement of the distance between the inferior aspect of the clavicular heads and the coronary sinus at both time points. RESULTS: The study population included 34 women (mean age, 29 ± 3 years; body mass index, 24 ± 4 kg/m(2)). The mean gestational age at third-trimester imaging was 237 ± 16 days (34 weeks ± 16 days); the mean number of days for postpartum imaging (baseline) was 107 ± 25 days (16 weeks ± 25 days). There was no statistical difference between the cardiac position at baseline (10.1 ± 1.2 cm) and during the third trimester (10.3 ± 1.1 cm; P = .22). CONCLUSION: Contrary to popular assumption, there is no significant vertical displacement of the heart in the third trimester of pregnancy relative to the nonpregnant state. Accordingly, there is no need to alter hand placement for chest compressions during cardiopulmonary resuscitation in pregnancy.

In vivo 1H MRS of human gallbladder bile at 3 T in one and two dimensions: detection and quantification of major biliary lipids.

In vitro (1)H MRS of human bile has shown potential in the diagnosis of various hepatopancreatobiliary (HPB) diseases. Previously, in vivo (1)H MRS of human bile in gallbladder using a 1.5 T scanner demonstrated the possibility of quantification of choline-containing phospholipids (chol-PLs). However, other lipid components such as bile acids play an important role in the pathophysiology of the HPB system. We have employed a higher magnetic field strength (3 T), and a custom-built receive array coil, to improve the quality of in vivo (1)H MRS of human bile in the gallbladder. We obtained significant improvement in the quality of 1D spectra (17 healthy volunteers) using a respiratory-gated PRESS sequence with well distinguished signals for total bile acids (TBAs) plus cholesterol resonating at 0.66 ppm, taurine-conjugated bile acids (TCBAs) at 3.08 ppm, chol-PLs at 3.22 ppm, glycine-conjugated bile acids (GCBAs) at 3.74 ppm, and the amide proton (-NH) arising from GCBAs and TCBAs in the region 7.76-8.05 ppm. The peak areas of these signals were measured by deconvolution, and subsequently the molar concentrations of metabolites were estimated with good accuracy, except for that of TBAs plus cholesterol. The concentration of TBAs plus cholesterol was overestimated in some cases, which could be due to lipid contamination. In addition, we report the first 2D L-COSY spectra of human gallbladder bile in vivo (obtained in 15 healthy volunteers). 2D L-COSY spectra will be helpful in differentiating various biliary chol-PLs in pathological conditions of the HPB system.

Detection and localization of bile duct leaks after cholecystectomy using Gd-EOB-DTPA-enhanced MR cholangiography: retrospective study of 16 patients.

OBJECTIVE: To determine if gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) cholangiography can detect and localize bile duct leaks in postcholecystectomy patients. MATERIAL AND METHODS: Four blinded independent radiologists performed a retrospective review of 16 consecutive patients who underwent MR cholangiography with intravenous Gd-EOB-DTPA for the evaluation of possible biliary leak. Image quality, ductal opacification, and presence and location of any bile leak were evaluated. An independent observer determined the criterion standard using a consensus of all chart, clinical, and imaging findings. RESULTS: All 6 bile leaks confirmed at endoscopic retrograde cholangiopancreatography were diagnosed by all reviewers (sensitivity, 100%). Of the 10 patients with no leak, only one reader incorrectly diagnosed a bile leak in a single case (specificity, 98%). The accuracy for detection of the site of leak with Gd-EOB-DTPA-enhanced MR cholangiography was 80%. CONCLUSION: Gadolinium-EOB-DTPA-enhanced MR can detect bile leaks with a high sensitivity and specificity.