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Biomedical subjects

M C Chui

Publications and source records attributed to M C Chui.

7 recordsLinked to original sources

Association between calcific aortic stenosis and hypercholesterolemia: is there a need for a randomized controlled trial of cholesterol-lowering therapy?

BACKGROUND: Calcific aortic stenosis may have common etiological factors with atherosclerosis. HYPOTHESIS: In this retrospective, case-control study, we aimed to determine whether there is an association between hypercholesterolemia and calcific aortic valve stenosis. METHODS: Consecutive patients undergoing single aortic or mitral valve replacement in a regional cardiothoracic surgical center were reviewed and preoperative patient characteristics were recorded: demographics, comorbidity (including coronary artery disease and associated risk factors), serum total cholesterol, lipid-lowering therapy, and serum creatinine. RESULTS: Serum total cholesterol concentrations were significantly higher in patients with calcific aortic stenosis than in controls (6.2+/-1.1 vs. 5.3+/-1.1 mmol/l; p < 0.001). The significant difference in serum cholesterol concentrations remained following correction for gender and body mass index (p = 0.02) and when patients with coronary artery disease were excluded (6.3+/-1.1 vs. 5.3+/-1.4 mmol/l; p<0.001). Subgroup analysis demonstrated that the association between elevated serum cholesterol concentrations and calcific aortic stenosis was particularly strong in patients with tricuspid aortic valves (6.4+/-1.2 vs. 5.3+/-1.1 mmol/l; p < 0.001) compared with those with bicuspid valves (5.9+/-1.1 vs. 5.3+/-1.1 mmol/l; p = 0.06). CONCLUSIONS: We conclude that hypercholesterolemia is associated with calcific aortic stenosis and may be implicated in its pathogenesis and progression. We believe that there is now a need for a randomized, controlled trial of cholesterol-lowering therapy in patients with calcific aortic stenosis.

Aged↗

Extracranial and extraspinal nerve sheath tumors: computed tomographic evaluation.

Thirty-five patients with 37 peripheral nerve sheath tumors (NST) (16 schwannomas, 11 neurofibromas, 5 plexiform and 1 diffuse neurofibroma, and 4 malignant NST) were studied respectively. The benign NST usually appeared on CT as well-defined oval, spherical or fusiform masses, centered at the expected anatomic location of a cranial, spinal, autonomic or peripheral nerve with characteristic displacement of adjacent muscles and blood vessels. None of the schwannomas appeared homogeneously hypodense on IV enhanced CT, whereas close to half of neurofibromas and plexiform neurofibromas were so. This fact, which had not been reported in the past, may be related to differences in inherent vascularity and blood-nerve barrier (fenestrated blood vessels) between schwannomas and neurofibromas and may be a useful distinguishing CT feature. The most reliable, though not infallible criterion of malignant NST was poor definition of their margins. Ninety-two per cent of NST (34 out of 37) were diagnosed or included in a limited differential pre-operatively.

Female↗

Transellar intercavernous carotid anastomosis with agenesis of internal carotid artery and right-sided descending aorta: case report.

We report a patient with a transellar intercavernous carotid anastomosis associated with right-sided descending aorta and agenesis of the internal carotid artery. To our knowledge, such an association has not been reported previously. Findings at angiography, computed tomography (CT) and dynamic CT are presented. We suggest that dynamic CT is not a reliable method of excluding this anomaly, a fact that has relevance to investigation prior to transphenoidal surgery for pituitary adenoma.

Aorta, Thoracic↗

Computed tomography of sphenoid sinus mucocele.

The clinical presentation of sphenoid sinus mucocele is usually dependent on the degree of involvement of adjacent structures. Since extension can be in any direction, there is a wide spectrum of symptomatology and clinical diagnosis can be difficult. Five cases of sphenoid sinus mucocele, four of which were demonstrated by computed tomography (CT), are presented. CT with its multiplanar display capability, is the diagnostic procedure of choice. It not only demonstrates the extent of the lesions non-invasively, but its ability to demonstrate bony expansion and destruction as well as density and enhancement pattern, will obviate the need for tomography. It has the greatest potential for differentiating other sphenoid and parasellar lesions.

Adenoma↗

Conventional and CT metrizamide myelography in Arnold-Chiari I malformation and syringomyelia.

Four normal controls and 26 cases of Arnold-Chiari I malformations and/or syringomyelia were reviewed. The pathologic cases included five isolated Arnold-Chiari I malformations, nine communicating syringomyelia, five idiopathic syringomyelia, four posttraumatic syringomyelia, one syringomyelia with hemangioblastoma, and two postshunt syringomyelia. The objectives of this study were to compare the accuracy of conventional metrizamide myelography with CT metrizamide myelography and to study indirectly the hydrodynamics of CSF flow in syringomyelia by comparing the sequential enhancement patterns of the spinal cords and cord cavities in the different groups of patients. Twenty-five patients underwent conventional metrizamide myelography immediately before CT metrizamide myelography, and one patient underwent CT metrizamide myelography only. Scans were obtained 1-2 hr, 4-8 hr, and 12-24 hr after injection of metrizamide, but not all patients were scanned during all three intervals. CT metrizamide myelography was found to be more sensitive than conventional metrizamide myelography in the diagnosis of both Arnold-Chiari I malformation and syringomyelia. Performing just an immediate and a delayed scan was found to be more cost-effective than doing all three scans. Contrary to previous reports, it was found that delayed (12-24 hr) scans demonstrated more syrinx cavities than intermediate ones. In studying the sequential enhancement patterns of the spinal cords and cord cavities, some interesting trends were observed that tend to support the theories of Aboulker and of Ball and Dayan of transneural passage of CSF into cord cavities in syringomyelia.

Adult↗