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Biomedical subjects

R Lambert

Publications and source records attributed to R Lambert.

At least 361 records · Page 20Linked to original sources
PubMedDate not supplied

Myocardial technetium 99m-labeled sestamibi single-photon emission computed tomographic imaging in the detection of coronary artery disease: comparison between early (15 minutes) and delayed (60 minutes) imaging.

BACKGROUND: Previous studies have demonstrated that there is a "partial" myocardial redistribution of 99mTc-labeled sestamibi (MIBI) between 1 and 3 hours after intravenous injection at stress. The purpose of this prospective study was to compare MIBI single-photon emission computed tomographic (SPECT) imaging performed 15 and 60 minutes after the injection at stress in the detection of coronary artery disease. METHODS AND RESULTS: Thirty-five patients with coronary artery disease (26 underwent coronary angiography and 23 had a positive 201Tl study result) were included in this study. SPECT imaging started 15 minutes after the injection of 25 to 30 mCi MIBI at peak stress (180-degree arc, 32 angles, 25 sec/view, and high-resolution collimator). Patients underwent reimaging at 60 minutes according to the same protocol and with the same gamma camera. A rest study was obtained 75 minutes after the injection of MIBI (25 to 30 mCi) at rest, 48 hours later. Images (divided for a total of 19 segments per patient) were interpreted by two blinded observers for patient diagnosis and segmental comparison. The patient diagnosis was the same for the two protocols: normal = 3, ischemia = 27, and scar = 5. The segmental agreement (kappa = 0.90) was 632/665 (95.0%). The imaging performed at 15 minutes detected normal, ischemia, and scar in 413, 189, and 63 segments, respectively, whereas the imaging performed at 60 minutes detected 422, 180, and 63 segments, respectively (difference not significant). The early and delayed images were placed side by side for subjective comparison of the extent of the defect. Early imaging showed slightly larger defects in six patients, equal defects in 24 patients, and slightly smaller defects in five patients. Ischemic/normal wall ratios were 0.67 +/- 0.16 at 15 minutes and 0.68 +/- 0.15 at 60 minutes. CONCLUSIONS: There is no clinically significant difference between SPECT imaging performed at 15 minutes or 60 minutes after the injection of MIBI at stress. Furthermore, this study showed that it is feasible to obtain good-quality MIBI images even 15 minutes after the injection at stress.

Adult↗
PubMedDate not supplied

Obstructive hydrocephalus-induced parkinsonism. I: Decreased basal ganglia regional blood flow.

A 17-year-old male developed acute parkinsonism after obstruction of a ventriculoperitoneal shunt with subsequent hydrocephalus. Following a previous shunt replacement, he developed florid parkinsonism which was associated with Parinaud syndrome. The initial single-photon emission computed tomography of the brain using 99mTc-hexamethylpropylenamine oxime demonstrated decreased cerebral blood flow in the regions of the left caudate and putamen. The patient underwent shunt revision with minimal improvement and therefore levodopa/carbidopa (Sinemet 100/25) was administered. Subsequently, he experienced almost complete recovery which may have been correlated with probable improvement of the basal ganglia regional cerebral blood flow. Parkinsonism associated with ventriculoperitoneal shunt obstruction is a rare but reversible disorder that is responsive to shunt replacement and antiparkinsonian drug administration. Cerebral perfusion studies may prove to be of value in delineating the pathophysiology of this complication.

Adolescent↗
PubMedDate not supplied

Retrograde biliary ultrathin endoscopy enhances biopsy of stenoses and lithotripsy.

Forceps biopsies of biliary stenoses are difficult to direct under fluoroscopy and for this reason may give spurious results. In addition, fluoroscopy does not prevent the electrohydraulic lithotripsy (EHL) probe from damaging the bile duct wall. Retrograde biliary endoscopy with the ultrathin endoscope (UTE) was tested in 12 patients to guide biopsies and in 6 patients to guide EHL. Results of biopsies were confirmed by surgery or the disease course in each of the 12 patients. Only one stone could not be fragmented and removed because the EHL probe could not be properly placed. The diagnosis of biliary stenosis may be markedly enhanced by using a UTE although at the risk of an endoscopic sphincterotomy and subsequent biliary infection. EHL with UTE is difficult and time consuming but further technical development may make it more practical immediately following sphincterotomy.

Aged↗