Effect of X-ray beam energy and image reconstruction technique on computed tomography numbers of various tissue equivalent materials

IntroductionComputed tomography (CT) numbers are used in radiological diagnosis, attenuation correction and radiotherapy treatment planning. Modern CT scanners use iterative reconstruction methods instead of the traditional filtered back projection (FBP). Hence, the investigation of CT number accuracy with image reconstruction techniques and X-ray tube potential (kVp) used in CT is warranted. The aim of this study is to evaluate the effect of Sinogram Affirmed Iterative Reconstruction (SAFIRE) Technique and image acquisition at different tube potentials on CT numbers of different tissue equivalent materials.MethodsImages of the Computerised Imaging Reference System Model 062M Electron Density Phantom were acquired at different tube potentials and reconstructed using FBP and different strengths of SAFIRE. Average CT numbers, in circular regions of interest, and their standard deviations were used to investigate any dependence of CT numbers on tube potentials and/or image reconstruction technique using non-parametric statistical tests with p-values set at 0.05.ResultsStatistically significant differences in CT numbers were not observed (p > 0.091) between the different image reconstruction techniques. CT number of bone equivalent materials increased significantly (p < 0.015), by up to 400 Hounsfield Units, when tube potential was decreased. Such extent of CT number change over the tube potentials range used in this study may influence diagnostic outcomes in lung nodule, contrast enhanced and calcium score studies. For all other tissue equivalent materials, the CT number did not change significantly for different tube potentials. Linear relationship was observed between CT numbers and electron densities.ConclusionThe study concludes that the CT numbers of all tissues did not change significantly with image reconstruction methods. However, the CT numbers of bone equivalent materials increased with decreasing tube potentials, which may result in misrepresentation of clinical information obtained.Implications for practiceWhen CT images are used to extract quantitative parameters such as calcium score, to characterise lung nodules and contrast enhanced structures, the kVp used for image acquisition should be carefully selected to avoid any misrepresentation of clinical information.     

Prevalence, predictors, and outcomes of conservative medical management in non-ST-segment elevation acute coronary syndromes in Gulf RACE-2

We assessed the prevalence, predictors, and in-hospital and long-term outcomes of conservative medical management for patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) compared with percutaneous coronary intervention (PCI) and coronary artery bypass graft surgery (CABG). This prospective study conducted from October 2008 to June 2009 in 65 hospitals from 6 Arabian Gulf countries included 30-day and 1-year mortality follow-up for 3661 patients. Compared with conservative management group (2859 patients; 78.1%), the PCI group (638; 17.4%) had significantly better unadjusted and adjusted in-hospital (odds ratio [OR]: 0.40, 95% confidence interval [CI]: 0.17-0.97), 30-day (OR: 0.44, 95% CI: 0.24-0.76) and 1-year (OR: 0.58, 95% CI: 0.40-0.87) mortality rates. Comparison with the CABG group (164; 4.5%) yielded similar results with inclusion of patients scheduled for CABG after hospital discharge. Independent predictors of conservative medical management were mainly country of residence and history of prior CABG.     

Relationship between white blood cell count and in-hospital outcomes in acute coronary syndrome patients from the Middle East

We evaluated the relationship between admission white blood cell (WBC) count and in-hospital outcomes in acute coronary syndrome (ACS) patients from the Middle East. Data were analyzed from 7806 consecutive patients with ACS who were divided into 4 groups (G) according to their WBC count (× 10(9)/L; G1: < 6.00; G2: 6.00-9.99; G3: 10.00-11.99; G4: ≥ 12.00). After significant covariate adjustment, those in G4 were 68% more likely to have cardiogenic shock than those in G1 (95% confidence interval [CI]: 1.05-2.68; P = .030) and G2 (odds ratio [OR], 2.02; 95% CI: 1.51-2.71; P < .001). Those in G4 were 2.02 times (95% CI: 1.11-3.67; P = .021) and 65% (95% CI: 1.17-2.32; P = .004) more likely to die in hospital than those in G1 and G2, respectively. Admission WBC count is an independent risk factor for in-hospital cardiogenic shock and mortality, in Middle Eastern patients with ACS. Novel therapeutic agents targeting WBCs in patients with ACS may improve outcomes.     

Impact of type of thrombolytic agent on in-hospital outcomes in ST-segment elevation myocardial infarction patients in the Middle East

Little is known about the impact of thrombolytic agents on in-hospital outcomes in the Middle East. The objective of this study was to evaluate the impact of thrombolytic agents on in-hospital outcomes in ST-segment elevation myocardial infarction (STEMI) patients in six Middle Eastern countries. Gulf Registry of Acute Coronary Events was a prospective, multinational, multicentre, observational survey of consecutive acute coronary syndrome patients admitted to 65 hospitals in 2006 and 2007. Out of 1,765 STEMI patients admitted to hospitals within 12 h of symptoms onset, 25, 43, and 30% were treated with streptokinase, reteplase, and tenecteplase, respectively. Median age of the study cohort was 50 (45–59) years and majority were males (89%). The overall median symptom onset-to-presentation and median door-to-needle times were 130 min (65–240) and 45 min (30–75), respectively. Streptokinase patients had worse GRACE risk scores compared to patients who received fibrin specific thrombolytics. Academic hospitals and cardiologists as admitting physicians were associated with the use of fibrin specific thrombolytics. After significant covariate adjustment, both reteplase [odds ratio (OR), 0.38; 95% CI: 0.18–0.79; P = 0.009] and tenecteplase (OR, 0.30; 95% CI: 0.12–0.77; P = 0.012) were associated with lower all-cause in-hospital mortality compared with streptokinase. No significant differences in other in-hospital outcomes were noted between the thrombolytic agents. In conclusion, in light of the study’s limitations, fibrin specific agents, reteplase and tenecteplase, were associated with lower all-cause in-hospital mortality compared to the non-specific fibrin agent, streptokinase. However, the type of thrombolytic agent used did not influence other in-hospital outcomes.     

155 vascular injuries: a retrospective study in Kuwait, 1992-2000.

OBJECTIVES: To audit the management of vascular trauma in Kuwait, 1992-2000. DESIGN: Retrospective open study. SETTING: Vascular surgery unit, teaching hospital, Kuwait. SUBJECTS: 155 patients with vascular injuries, most of which (n = 118) involved the extremities. 21 had neck injuries, 10 abdominal, and 6 chest. INTERVENTION: Revascularisation usually using the long saphenous vein in addition to direct repair or end-to-end anastomosis. MAIN OUTCOME: Morbidity (amputation) and mortality. RESULTS: Four lower limb grafts failed, two of which (2/69, 3%) required amputation. Overall, four patients died (3%), one of pulmonary embolism and 3 of severe injuries to major abdominal vessels. 3/10 patients with abdominal vascular trauma died. Mean (SD) follow up period was 4.4 (2) years. CONCLUSIONS: Civilian violence has increased in Kuwait. Vascular trauma to abdominal vessels is associated with high mortality. Autogenous saphenous vein forms an excellent conduit for revascularisation.     

Immunological and morphological characterisation of nucleated cells other than sperm in semen of oligospermic donors

Nucleated cells other than sperm (NCOS) were obtained from semen samples of oligospermic donors. The cells, after separation from sperm, were studied by immunological and morphological techniques including electron microscopy (EM). Using an indirect immunofluorescence (IIF) test, more than 95% of the NCOS reacted with xenoantisera specific for human sperm and germ cells but showed less than 5% reactivity with monoclonal antibodies (MoAbs) directed against surface markers of different leucocyte subsets or cytokeratin. This indicated that the majority of NCOS were germ cells in origin. These results were concordant to those obtained by EM which showed the presence of germ cells at various stages of differentiation. Our data therefore show that the application of immunological techniques could help and may replace laborious EM in the identification of the different cell types among NCOS. Also, the results emphasize that germ cells and not leucocytes appear to be the major cell type among NCOS, a concept which could have therapeutic and biological implications.     

Soft tissue augmentation for implant dentistry

This article describes the soft tissue gingival augmentation techniques used in periodontal therapy and their advantages in implant dentistry. The procedures described include the free gingival graft, apically and coronally positioned grafts, the pouch procedure (or subepithelial connective tissue graft), the inverted pouch procedure or roll technique, and combination techniques. The author presents solutions that most clinicians commonly use when placing implants in the esthetic zone.     

Clinical and histologic studies of a Qatari family with myofibrillar myopathy

The current study reports the first family with confirmed myofibrillar myopathy MFM in the Middle East and the third family worldwide. This study highlights the importance of considering MFM in young patients presenting with idiopathic cardiomyopathy, arrhythmia or atrioventricular block in the Gulf states. This is the first report that presented 2 different types of cardiomyopathy and 2 different indications of permanent pacemaker placement in the same generation of a family with MFM. This report studies a Qatari family consisting of one brother and 3 sisters. The brother had restrictive cardiomyopathy at the age of 16 years. One sister underwent heart transplantation for severe hypertrophic cardiomyopathy at the age of 15 years, the other sister had permanent pacemaker for complete heart block at the age of 21 years. This report is focused mainly on the clinical presentation and investigations carried out for the brother including echocardiogram, cardiac catheterization, cardiac and skeletal muscle biopsy, and electromyography and electrophysiology studies. The study findings support the diagnosis of MFM.