Israel Medical Association Journal

Background: Coronary computed tomography angiography (CCTA) is an established modality for ruling out coronary artery disease. However, it has been suggested that CCTA may be a source of non-negligible radiation exposure.

Objectives: To evaluate the potential degradation in coronary image quality when using prospective gated (PG) CCTA as compared with retrospective gated (RG) CCTA in chest pain evaluation.

Methods: The study cohort comprised 216 patients: 108 consecutive patients in the PG CCTA arm and 108 patients matched for age, gender and heart rate in the RG CCTA arm. Scans were performed using a 64-slice multidetector CT scanner. All 15 coronary segments were evaluated subjectively for image quality using a 5-point visual scale. Dose-length product was recorded for each patient and the effective radiation dose was calculated

Results: The PG CCTA technique demonstrated a significantly higher incidence of step artifacts in the middle and distal right coronary artery, the distal left anterior descending artery, the second diagonal, the distal left circumflex artery, and the second marginal branches. Nevertheless, the diagnostic performance of these scans was not adversely affected. The mean effective radiation doses were 3.8 ± 0.9 mSv vs.17.2 ± 3 mSv for PG CCTA and RG CCTA, respectively (P < 0.0001).

Conclusions: Artifacts caused by the PG CCTA technique (64 MDCT) scanners tended to appear in specific coronary segments but did not impair the overall diagnostic quality of CCTA and there was a marked reduction in radiation exposure. We conclude that 64-slice PG CCTA is suitable for clinical use, especially for acute chest pain "fast track" evaluation targeted at relatively young subjects in a chest pain unit.
 

Background: Coronary CT angiography is an accurate imaging modality; however, its main drawback is the radiation dose. A new technology, the "step and shoot," which reduces the radiation up to one-eighth, is now available.

Objectives: To assess our initial experience using the "step-and-shoot" technology for various vascular pathologies.

Methods: During a 10 month period 125 consecutive asymptomatic patients (111 men and 14 women aged 25–82, average age 54.9 years) with various clinical indications that were appropriate for step-and-shoot CCTA[1] (regular heart rate < 65 beats/minute and body weight < 115 kg) were scanned with a 64-slice multidetector computed tomography Brilliance scanner (Philips, USA). The preparation protocol for the scan was the same as for the regular coronary CTA. All examinations were interpreted by at least one experienced radiologist and one experienced interventional cardiologist. The quality of the examinations was graded from 1 (excellent imaging quality of all coronary segments) to 4 (poor quality, not diagnostic). There were 99 patients without a history of coronary intervention, 13 after coronary stent deployment (19 stents), and 3 after coronary artery bypass graft.

Results: Coronary interpretation was obtained in 122 examinations (97.6%). The imaging quality obtained was as follows: 103 patients scored 1 (82.4%), 15 scored 2 (12%), 4 scored 3 (3.2%) and 3 scored 4 (2.4%). The grades were unrelated to cardiac history or type of previous examinations. Poor image quality occurred because of sudden heart rate acceleration during the scan (one patient), movement and respiration (one patient), and arrhythmia and bad scan timing (in one). Two patients were referred to percutaneous coronary intervention based on the CCTA findings, which correlated perfectly.

Conclusions: Step-and-shoot CCTA is a reliable technique and CCTA algorithm comparable to the regular CCTA. This technique requires the lowest radiation dose, as compared to other coronary imaging modalities, that can be used for all CCTA indications based on the inclusion criteria of low (> 65 bpm) and stable heart rate.

Background: Many patients present to the emergency department with chest pain. While in most of them chest pain represents a benign complaint, in some patients it underlies a life-threatening illness.

Objectives: To assess the routine evaluation of patients presenting to the ED[1] with acute chest pain via the utilization of a cardiologist-based chest pain unit using different non-invasive imaging modalities.

Methods: We evaluated the records of 1055 consecutive patients who presented to the ED with complaints of chest pain and were admitted to the CPU[2]. After an observation period and according to the decision of the attending cardiologist, patients underwent myocardial perfusion scintigraphy, multidetector computed tomography, or stress echocardiography.

Results: The CPU attending cardiologist did not prescribe non-invasive evaluation for 108 of the 1055 patients, who were either admitted (58 patients) or discharged (50 patients) after an observation period. Of those remaining, 445 patients underwent MDCT[3], 444 MPS[4], and 58 stress echocardiography. Altogether, 907 patients (86%) were discharged from the CPU. During an average period of 236 ± 223 days, 25 patients (3.1%) were readmitted due to chest pain of suspected cardiac origin, and only 8 patients (0.9%) suffered a major adverse cardiovascular event.

Conclusions: Utilization of the CPU enabled a rapid and thorough evaluation of the patients’ primary complaint, thereby reducing hospitalization costs and occupancy on the one hand and avoiding misdiagnosis in discharged patients on the other.
 

[1] ED = emergency department

[2] CPU = chest pain unit

[3] MDCT = multidetector computed tomography

[4] MPS = myocardial perfusion scintigraphy

Background: Obesity has become a major public health problem worldwide.

Objectives: To examine the effect of orlistat in promoting weight loss and its specific effect on the visceral adipose tissue and subcutaneous adipose tissue as evaluated by computed tomography.

Methods: A prospective case series study of 10 obese subjects was conducted. The 6 women and 4 men, age 50–67 years (mean 59 ± 8 years), had a mean body mass index of 34.1 ± 3.2 kg/m². All subjects were prescribed a mildly hypocaloric diet (600 kcal/day deficit). In addition, all subjects were treated with orlistat 120 mg 3 times a day for 20.1 ± 7 weeks.

Results: The subjects had lost approximately 8.2 kg each, or 8.4% of their initial body weight. Mean body weight decreased from 98 ± 13 to 89.8 ± 13.6 kg at the last follow-up visit (P = 0.0001) mean BMI[1] decreased from 34.1 ± 3.2 to 30.3 ± 3.9 kg/m² (P = 0.0001), and mean waist circumference from 113.8 ± 11.4 to 107.6 ± 10 cm (P = 0.0006). Mean total abdominal adipose tissue volume, evaluated by computed tomography, decreased from 426 ± 104.3 to 369.8 ± 99.6 mm³ (P = 0.0001). Mean abdominal SAT[2] volume decreased from 251.1 ± 78.8 to 224 ± 81.1 mm³ (P = 0.006), and mean abdominal VAT[3] volume decreased from 176 ± 76.7 to 141.6 ± 67 mm³ (P = 0.0001). Thus, the total abdominal adipose tissue volume for the whole group decreased by 15.4%, and most of this decrease was attributable to the reduction in VAT (24.8%) as opposed to SAT (only 12% reduction) (P = 0.03). The weight reduction that occurred during the study was accompanied by a statistically significant reduction in levels of total cholesterol, low density lipoprotein-cholesterol, triglycerides, and fasting blood glucose.

Conclusions: Our results demonstrate the effect of orlistat in reducing human visceral adipose tissue as evaluated by CT. The benefit of the treatment is further supported by the statistically significant reduction in cardiovascular risk factors.

 
[1] BMI = body mass index

[2] SAT = subcutaneous adipose tissue

[3] VAT = visceral adipose tissue

 

Background: Injury to patent grafts or cardiac chambers may occur during reoperation after coronary artery bypass grafting. Preoperative spatial localization of bypass grafts with computed tomography may improve the safety of these procedures.

Objectives: To characterize patients who undergo CT before repeat operations after previous coronary artery bypass grafting, and evaluate its benefit in terms of surgical outcome.

Methods: We compared 28 patients who underwent cardiac gated CT angiography before reoperation (CT group) to 45 re-do patients who were not evaluated with CT (no‑CT group).

Results: The two groups were similar in most preoperative and operative characteristics. The CT group, however, included more patients with patent saphenous vein grafts and fewer with emergency operations, acute myocardial infarction and need for intraaortic balloon pump support. During mid-sternotomy, there was no injury to grafts in the CT group, while there were two patent grafts and three right ventricular injuries in the no-CT group. There was no significant difference in perioperative mortality (3.6% vs. 8.9%). The overall complication rate in the CT group was 21.4% compared to 42.2% in the no‑CT group (P = 0.07). The only independent predictors of postoperative complications were diabetes mellitus, preoperative stroke and preoperative acute MI[1].

Conclusions: The patency and proximity of patent grafts to the sternum are well demonstrated by multidetector CT and may provide the surgeon with an important roadmap to avoid potential graft injury. A statistical trend towards reduced complications rate was demonstrated among patients who underwent CT angiography before their repeat cardiac operation. Larger series are required to demonstrate a statistically validated complication-free survival benefit of preoperative CT before repeat cardiac surgery.