Correlation between ABO blood groups, major risk factors, and coronary artery disease

To investigate a possible association of ABO blood groups with coronary artery disease in well-documented patients, we designed a cross-sectional study of 2026 patients, known case of coronary artery disease in angiography, who underwent coronary artery bypass graft at Tehran Heart Center, with regard to coronary artery disease major risk factors as well as ABO blood groups. Analysis did not show any significant difference between the frequency of ABO blood groups in coronary artery disease patients compared to the Iranian general population. In addition, frequency of cardiac risk factors was similar in coronary artery disease patients with different blood groups. Therefore, these finding suggest that there is no correlation between various ABO blood groups and development of coronary artery disease. Moreover, the prevalence of major risk factors was equal in patients with different blood groups, and blood groups had no impact on development of premature coronary artery disease in individual subjects.     

Volvulus of the sigmoid colon in a child

Sigmoid volvulus although a common cause of large bowel obstruction in the elderly, is considered rare in the pediatric age group. We report a case of sigmoid volvulus in a 10-year-old child with mental retardation and myopathy. The various predisposing factors for sigmoid volvulus in children are discussed, and the literature on the subject is also reviewed.     

Osteoporotic vertebral collapse: percutaneous vertebroplasty and local kyphosis correction

Forty-six cases of osteoporotic vertebral collapse (27 thoracic, 19 lumbar) were treated by means of percutaneous vertebroplasty in a hyperlordosis position. Institutional review board approval and informed consent were obtained. Kyphosis reducibility was preprocedurally estimated from the angular difference between neutral and hyperlordosis positions. Effective reduction was the angular difference in neutral positions before and after vertebroplasty. Reduction (< or =14 degrees ; mean, 6.43 degrees) was obtained in cases with estimated reducibility greater than 5 degrees (31 cases, 67%), which is a 34% (6.5 degrees of 19.1 degrees ) mean reduction. A significantly greater level of kyphosis reduction was observed in cases with intravertebral clefts (20 cases, 43%) at hyperlordosis than in those without (7.2 degrees vs 4.9 degrees ; P < .01). Vertebroplasty may reduce kyphosis due to localized collapsed vertebrae; intravertebral mobility and cleft suggest this possibility.     

Perspectives of matrix convex functions

In this paper, we generalize the main results of [Effros EG, (2009) Proc Natl Acad. Sci USA 106:1006–1008]. Namely, we provide the necessary and sufficient conditions for jointly convexity of perspective functions and generalized perspective functions.     

SPECT imaging in the diagnosis of pulmonary embolism: automated detection of match and mismatch defects by means of image-processing techniques.

SPECT of ventilation/perfusion (V/Q) lung scans not only improves the diagnostic accuracy of the method but also facilitates the application of advanced image-processing techniques. On the basis of such techniques, our study aimed at developing a procedure that automatically analyzes V/Q lung scans with regard to match and mismatch defects. METHODS: Fifty-three patients with suspected pulmonary embolism had lung scans using the SPECT technique as well as 16-slice multidetector-row spiral CT within an interval of 48 h. After iterative image reconstruction and computerized linear registration of the V/Q scans, the ventilation was normalized to the perfusion. For the automated detection of mismatch defects, the perfusion was subtracted from the ventilation, whereas for the detection of match defects, the perfusion was subtracted from the inverted ventilation. Two experienced referees assessed all images. The final diagnosis was made at a consensus meeting while taking into account all of the imaging modalities, laboratory tests, clinical data, and evaluation of a follow-up period. RESULTS: The sensitivity, specificity, and accuracy of the conventional visual assessment were 0.91, 0.97, and 0.94, respectively, compared with 0.95, 0.84, and 0.89, respectively, for the automated algorithm. Artifacts imitating mismatch defects in the pulmonary recesses accounted for the relatively low specificity of the automated analysis. Artifacts of that kind were found in 15 patients and led to a false-positive diagnosis in 5 patients. However, by combining the visual and the automated approach, all artifacts could be easily identified leading to a sensitivity, specificity, and accuracy of 0.95, 1.0, and 0.98, respectively. Additionally, in all 12 patients of the cohort with highly heterogeneous ventilation and perfusion, the automated analysis made correct diagnoses. CONCLUSION: Because of the 3-dimensional properties of the SPECT data, the analysis of lung scans can be automated and objectified. The algorithm produces images that are easy to read and well suited for demonstration. Because of artifacts in the pulmonary recesses introduced by the automated approach, its diagnostic accuracy does not reach the level of the conventional analysis yet. Could these artifacts be overcome, the efficiency of the automated algorithm would be at least equivalent to that of conventional image interpretation. At present, best results can be achieved by combining both approaches.     

Intermittent drop in blood flow velocity in the internal carotid artery and its branches

Extracranial Doppler sonography and transcranial Doppler sonography (TCD) allow the assessment and monitoring of hemodynamic and embolic events in cerebrovascular diseases. We describe an unusual hemodynamic phenomenon in a patient with intracranial carotid siphon stenosis and no clinical symptoms of stenosis. TCD examination suggested and angiography confirmed stenosis of the left internal carotid artery siphon. TCD examination revealed a sudden, intermittent drop in blood flow velocity in both the prestenotic and poststenotic segments of the internal carotid artery, whereas cardiac hemodynamic parameters were unaffected. Embolic signals were detected in the poststenotic vessels only. We speculate that such sonographic findings may be caused by intermittent vessel occlusions due to the reversible displacement of an intraluminal thrombus in relation to the cardiac cycle.