Sunnybrook Health Sciences Centre

About: Sunnybrook Health Sciences Centre is a healthcare organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Medicine. The organization has 7689 authors who have published 15236 publications receiving 523019 citations. The organization is also known as: Sunnybrook.

Radiation dose from multidetector row CT imaging for acute stroke.

Abstract: The objective of this study was to determine the radiation dose delivered during comprehensive computed tomography (CT) imaging for acute stroke. All CT examinations performed over 18 months using our acute stroke protocol were included. Protocol includes an unenhanced CT head, CT angiography from the arch to vertex, CT perfusion/permeability, and an enhanced CT head. All imaging was acquired with a 64-MDCT. Examinations where any element of the protocol was repeated or omitted due to mistimed injection or patient motion were excluded. Dose-length products (DLP) for all components of each examination were obtained from dose reports generated at the time of acquisition, separating neck, and head calculations. Effective doses for each examination were calculated using the DLP and normalized values of effective dose per DLP appropriate for the body regions imaged. Ninety-five examinations were included. Mean DLP was 6,790.0 mGy·cm. Effective doses ranged from 11.8 to 27.3 mSv, mean effective dose of 16.4 mSv. Mean effective dose for acquisition of the unenhanced head was 2.7 mSv. Largest contribution to effective dose was the CTA with a mean effective dose of 5.4 mSv. Mean effective dose for the CT perfusion was 4.9 mSv. A comprehensive CT acute stroke protocol delivered a mean effective dose of 16.4 mSv, which is approximately six times the dose of an unenhanced CT head. These high-dose results must be balanced with the benefits of the detailed anatomic and physiologic data obtained. Centers should implement aggressive dose reduction strategies and freely use MR as a substitute.

Recall of intraoperative events after general anaesthesia and cardiopulmonary bypass.

Abstract: We wished to identify patients able to recall intraoperative events after general anaesthesia involving cardiopulmonary bypass (CPB). A balanced anaesthetic technique consisting of benzodiazepines, low dose fentanyl (15.9 +/- 8.5 micrograms.kg-1) and a volatile agent was employed. Perioperative recall was sought utilizing a structured interview on the fourth or fifth postoperative day. During 20 mo 837 patients underwent CPB. Seven hundred patients (84%) were able to respond to a structured postoperative interview. A detailed chart review was performed in patients with recall and in 60 randomly selected patients without recall. Eight patients (1.14%) reported recall of intraoperative events. We were unable to identify any differences between the two groups with respect to narcotic, benzodiazepine dosage or usage of inhalational agents. The incidence of recall in patients undergoing cardiac surgery was less in our group than previously reported. It is, however, higher than the 0.2% incidence recently reported in patients undergoing non-cardiac surgery. This is probably due to patient characteristics and intraoperative factors which make it difficult to avoid periods of relatively light anaesthesia during cardiac surgery.

Effect of PET Before Liver Resection on Surgical Management for Colorectal Adenocarcinoma Metastases: A Randomized Clinical Trial

Abstract: OBJECTIVES To determine the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases and to investigate the effect of PET-CT on survival and the association between the standardized uptake value (ratio of tissue radioactivity to injected radioactivity adjusted by weight) and survival. DESIGN, SETTING, AND PARTICIPANTS A randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months was conducted between 2005 and 2013, involving 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions. INTERVENTIONS Patients were randomized usin ga2t o 1r atio to PET-CT or control. MAIN OUTCOMES AND MEASURES The primary outcome was a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT. Survival was a secondary outcome. RESULTS Of the 263 patients who underwent PET-CT, 21 had a change in surgical management (8.0%; 95% CI, 5.0%-11.9%). Specifically, 7 patients (2.7%) did not undergo laparotomy, 4 (1.5%) had more extensive hepatic surgery, 9 (3.4%) had additional organ surgery (8 of whom had hepatic resection), and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed and the cavity was closed. Liver resection was performed in 91% of patients in the PET-CT group and 92% of the control group. After a median follow-up of 36 months, the estimated mortality rate was 11.13 (95% CI, 8.95-13.68) events/1000 person-months for the PET-CT group and 12.71 (95% CI, 9.40-16.80) events/1000 person-months for the control group. Survival did not differ between the 2 groups (hazard ratio, 0.86 [95% CI, 0.60-1.21]; P = .38). The standardized uptake value was associated with survival (hazard ratio, 1.11 [90% CI, 1.07-1.15] per unit increase; P < .001). The C statistic for the model including the standardized uptake value was 0.62 (95% CI, 0.56-0.68) and without it was 0.50 (95% CI, 0.44-0.56). The difference in C statistics is 0.12 (95% CI, 0.04-0.21). The low C statistic suggests that the standard uptake value is not a strong predictor of overall survival.