Faculty Bibliography

Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

BACKGROUND: At teaching hospitals, radiology residents give preliminary reports for imaging studies requested from the Emergency Department (ED). Discrepancy rates between preliminary and final reports represent an important performance indicator. PURPOSE: To present a system for feedback and follow-up of discrepancies, identify the variables associated with the rate and severity of such discrepancies, target the weaknesses, and suggest the need of a standard reference value for comparison among institutions. MATERIAL AND METHODS: A monitoring and communication system between the Department of Diagnostic Radiology and Emergency Department was initiated to mark and follow all studies from the ED for which the official reading was different than the preliminary interpretation. Data analysis was performed on all studies from 1 June 2011 to 31 May 2012, based on the severity of the discrepancy, imaging modality, resident training level, and organ system. The distribution of the number of discrepancies among the different resident levels and imaging modalities was determined, as well as the distribution of three severity scores in correlation with other variables. RESULTS: The overall discrepancy rate was 1.62%. The discrepancy rate was higher for first and second year residents (1.62% and 1.96%) than for third and fourth year residents (1.35% and 1.24%). It was higher for computed tomography (2.13%) than for radiographs (1.29%) and ultrasound (0.8%) (P value < 0.01), and higher for musculoskeletal (1.61%) than non-musculoskeletal (0.99%) radiographs (P value = 0.0003). Discrepancies with severity score one constituted 35.5% of the total discrepancies, those with severity scores two and three constituted 22.9% and 41.6%, respectively. CONCLUSION: We have demonstrated a system for follow-up of discrepancy in interpreting emergency radiology studies, and recorded the discrepancy rate, with further analysis based on different variables. In terms of quality assurance, a periodical analysis might help to reduce the number of discrepant reports by targeted intervention.

PURPOSE: Venous thromboembolism (VTE) is a common cause of morbidity and mortality in hospitalized and surgical patients. To reduce risk, perioperative VTE prophylaxis is recommended for cancer patients undergoing surgical or interventional procedures. Magnetic resonance imaging (MRI) is increasingly used in interventional oncology when alternative imaging modalities do not adequately delineate malignancies. Extended periods of immobilization during MRI-guided interventions necessitate an MR compatible sequential compression device (SCD) for intra-procedural mechanical VTE prophylaxis. Such devices are not commercially available. MATERIALS AND METHODS: A standard SCD routinely used at our institution for VTE prophylaxis during interventional procedures was used. To satisfy MR safety requirements, the SCD controller was placed in the MR control room and connected to the compression sleeves in the magnet room through the wave guide using tubing extensions. The controller pressure sensor was used to monitor adequate pressure delivery and detect ineffective low or abnormal high pressure delivery. VTE prophylaxis was provided using the above mentioned device for 38 patients undergoing MR-guided ablations. RESULTS: There was no evidence of device failure due to loss of pressure in the extension tubing assembly. No interference with the anesthesia or interventional procedures was documented. CONCLUSION: Although the controller of a standard SCD is labeled as "MR-unsafe", the SCD can be used in interventional MR settings by placing the device outside the MR scanner room. Using serial tubing extensions did not cause device failure. The described method can be used to provide perioperative mechanical VTE prophylaxis for high risk patients undergoing MR-guided procedures.