Comparison of Measured and Estimated CT Organ Doses for Modulated and Fixed Tube Current:: A Human Cadaver Study.

RATIONALE AND OBJECTIVES: The aim of this study was to compare the directly measured and the estimated computed tomography (CT) organ doses obtained from commercial radiation dose-tracking (RDT) software for CT performed with modulated tube current or automatic exposure control (AEC) technique and fixed tube current (mAs). MATERIALS AND METHODS: With the institutional review board (IRB) approval, the ionization chambers were surgically implanted in a human cadaver (88 years old, male, 68 kg) in six locations such as liver, stomach, colon, left kidney, small intestine, and urinary bladder. The cadaver was scanned with routine abdomen pelvis protocol on a 128-slice, dual-source multidetector computed tomography (MDCT) scanner using both AEC and fixed mAs. The effective and quality reference mAs of 100, 200, and 300 were used for AEC and fixed mAs, respectively. Scanning was repeated three times for each setting, and measured and estimated organ doses (from RDT software) were recorded (N = 3*3*2 = 18). RESULTS: Mean CTDIvol for AEC and fixed mAs were 4, 8, 13 mGy and 7, 14, 21 mGy, respectively. The most estimated organ doses were significantly greater (P < 0.01) than the measured organ doses for both AEC and fixed mAs. At AEC, the mean estimated organ doses (for six organs) were 14.7 mGy compared to mean measured organ doses of 12.3 mGy. Similarly, at fixed mAs, the mean estimated organ doses (for six organs) were 24 mGy compared to measured organ doses of 22.3 mGy. The differences among the measured and estimated organ doses were higher for AEC technique compared to the fixed mAs for most organs (P < 0.01). CONCLUSIONS: The most CT organ doses estimated from RDT software are greater compared to directly measured organ doses, particularly when AEC technique is used for CT scanning.

Imaging and intervention for coronary artery disease following irradiation of malignant thymoma.

Thymomas are rare malignant epithelial growths, constituting 20% of mediastinal tumours. Resection followed by irradiation may be employed in all thymomas except for stage 1 thymomas. Mediastinal irradiation is associated with coronary artery disease. The mean duration of presentation of post-irradiation coronary artery disease is 16 years (range 3-29 years). In our patient coronary artery disease was found only a year post irradiation. A 55 year old male who presented with complaints of dyspnoea, retrosternal chest pain and heaviness since one year underwent resection for malignant thymoma followed by radiotherapy. He presented with coronary artery disease a year after undergoing mediastinal irradiation. On follow-up, patient was treated successfully by coronary artery bypass graft. This case is an unusual occurrence and suggests that mediastinal irradiation may result in significant coronary artery disease as early as within one year.

Imaging and intervention of paraneoplastic effect of a right atrial myxoma on factor VII activity levels.

We present the case of a 64-year-old Pakistani man with right atrial myxoma, recently diagnosed with acquired severe factor VII (FVII) deficiency. The patient presented with a history of chronic hiccups and weight loss. Initial evaluation revealed an isolated prolonged prothrombin time, severely reduced FVII activity level, and a giant right atrial myxoma protruding into the right ventricle on computed tomographic thorax and echocardiography. After surgical resection, the patient maintained normal prothrombin time with increased FVII activity level in the immediate 24 hours postoperatively, and a dramatically high level of FVII activity at the 2-month follow-up. We believe that the paraneoplastic effect of myxoma on the FVII activity levels is previously unreported. In addition, we believe that hiccups as a presenting symptom for a myxoma with an atypical origin from the lateral wall of the right atrium has not been reported.

Trends of surgical career selection among medical students and graduates: a global perspective.

BACKGROUND: Declining trends in surgery have been well-researched in the North American region, but little is known about the international dynamics affecting this phenomenon. A comprehensive approach to this emerging issue is lacking. OBJECTIVES: Our objective in this study is to explore global trends related to medical student interest in surgical careers. We will also identify factors influencing the choice of surgery as a career and outline practical interventions to nurture interest in these fields, as described in the literature. DESIGN: We present a focused review of worldwide trends of surgical career selection among medical students of geographically distant and diverse sociocultural backgrounds. A systematic literature search was performed using PubMed. The studies were conducted over the last fifteen years with the study populations scattered over 6 continents. RESULTS: North American studies have shown a declining trend for medical students to select surgery as a career, but a recent recovery has been observed. However, surgery is still the popular choice of career among Middle Eastern and Far-Eastern Asian men. Sociocultural variants and personal satisfaction are likely influential factors with financial rewards being the least significant. Surgery is also popular in Nigeria despite their increased awareness of risk of HIV/AIDS associated with surgery. A decline in surgery has been observed in Australia, New Zealand, and South Africa. Medical students and graduates of Greece, Switzerland, and the UK mostly prefer nonsurgical careers. Multiple extrinsic and intrinsic factors appear to play a role for such a phenomenon. Specific interventions are now being used to create a rebound effect for such a declining trend observed in most of the regions worldwide. CONCLUSIONS: Global trends show a variation of interest in surgery as a career option throughout the 6 continents. Possible factors affecting this phenomenon are similar among geographically distant and diverse student cultures.

Late concomitant pseudoaneurysm and arteriovenous fistula of the subclavian artery: a developing country perspective.

Concomitant subclavian artery pseudoaneurysm and arteriovenous (AV) fistula has been rarely reported. We report a case of late concomitant pseudoaneurysm and AV fistula of the subclavian artery caused by a gunshot wound. Open surgical approach with an infraclavicular approach was used; subclavian artery was repaired with a Gortex interposition graft and subclavian vein was ligated. The postoperative course was uneventful. In developing countries, where the endovascular expertise is unavailable or if the lesion is large, open surgical approach provides similar results as an endovascular approach.