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Biomedical subjects

R P duCret

Publications and source records attributed to R P duCret.

At least 19 recordsLinked to original sources
PubMed1996

Imaging of small airways disease.

High-resolution computed tomography (HRCT) is the most useful modality for imaging of small airways disease. Direct signs of small airways disease that appear on HRCT scans are the result of changes in the airway wall or lumen. Abnormal small airways can be seen as tubular, nodular, or branching linear structures on HRCT scans. Indirect signs of small airways disease result from changes in the lung parenchyma distal to the diseased small airway and include air trapping, subsegmental atelectasis, centrilobular emphysema, and air-space nodules. Diverse inflammatory and infectious processes, such as bronchiolitis obliterans (BO), bronchiolitis obliterans with organizing pneumonia (BOOP), smoking-related diseases, and asthma affect the small airways of the lungs. HRCT findings of BO include air trapping and bronchiectasis. The predominant findings of BOOP are consolidation and ground-glass attenuation. HRCT can show abnormalities such as small nodules and areas of ground-glass attenuation even in asymptomatic smokers, but emphysema predominates in smokers with moderate or severe obstructive disease. Patients with asthma can have thickened airway walls, plugged large and small airways, subsegmental atelectasis, and air trapping, but emphysema is rarely seen even in severe asthma patients. HRCT scans can often accurately depict disease processes in the small airways and can occasionally lead to a specific diagnosis from among several clinically relevant possibilities.

Asthma↗
PubMed1994

Pectus excavatum: abnormal exercise scintigraphy with normal coronary arteries.

Pectus excavatum is the most common congenital abnormality of the chest wall, and is frequently associated with chest pain. The invasive, as well as the ECG and echocardiographic assessment of possible coronary artery disease (CAD) in adults with moderate to severe forms of this deformity, is often complicated by the associated displacement of the heart in the chest cavity in these patients. We present findings in a 67-yr-old male that demonstrate that the predictive accuracy of positive stress radionuclide ventriculogram (RVG) and SPECT scintigraphic studies may be significantly reduced in patients with moderate to severe forms of this abnormality. Our findings also suggest, however, that either lateral or even a shallow left posterior oblique detector positioning during RVG, a significantly revised SPECT acquisition orbit, or planar imaging may provide a more accurate means to assess possible CAD in these patients. Like-wise, physician input would appear to be invaluable in determining the optimal mode of imaging and the acquisition protocol for patients with pectus excavatum.

Adult↗
PubMed1992

Liver transplant rejection and cholestasis: comparison of technetium 99m-diisopropyl iminodiacetic acid hepatobiliary imaging with liver biopsy.

To determine whether the scintigraphic evaluation of technetium-99m diisopropyl iminodiacetic acid (DISIDA) uptake and excretion can distinguish among liver transplant patients with biopsy evidence for rejection, cholestasis or neither condition, we reviewed scintigrams and biopsies in 36 patients. There were 76 scintigrams with corresponding biopsies. Uptake and excretion were graded from image data on scales reflecting normal through severely abnormal values. Biopsies were evaluated for findings of cholestasis and rejection. The majority of scintigrams demonstrated normal uptake (60/75, 80%) and delayed excretion (65/76, 85%), which was most marked immediately after transplantation. One-way analysis of variance showed that the mean excretion values significantly differed between patients with normal biopsies and those with cholestasis and/or rejection (P = 0.0003). However, mean uptake scores demonstrated no statistically significant difference between these two groups of patients (P = 0.1). These findings suggest that 99mTc-DISIDA scintigraphy can differentiate between transplants with and without rejection/cholestasis but not between rejection and cholestasis. If 99mTc-DISIDA excretion is normal, rejection and cholestasis are unlikely.

Cholestasis↗
PubMed1992

Aerosol scintigraphy in the assessment of therapy for cystic fibrosis.

Thirteen patients with cystic fibrosis (aged 11 to 32 years) who were hospitalized for exacerbation and who had sputum cultures positive for Pseudomonas organisms were treated initially for 4 days with bronchodilators and physiotherapy followed by the addition of antibiotic (14 days, n = 8) or placebo (14 days, n = 4; 7 days, n = 1). Tc-99m DTPA aerosol scintigraphy was performed on the day before bronchodilators and physiotherapy, on the day before antibiotic or placebo, and on the day after completion of antibiotic or placebo therapy. Scintigrams were evaluated for change in the number of nonventilated segments and change in the number of bronchial deposits of aerosol. Sixty-nine percent of patients showed improvement after bronchodilators and physiotherapy alone. Sixty-two percent showed further improvement after antibiotic or placebo was added; this improvement was independent of whether antibiotic or placebo was administered (P greater than 0.1). These aerosol scintigraphy results failed to demonstrate that the effectiveness of bronchodilators and physiotherapy is enhanced by antibiotics in the treatment of cystic fibrosis exacerbations.

Adult↗
PubMed1991

Ectopic splenomegaly in Felty's syndrome.

A 50-year-old woman with Felty's syndrome, who presented with "menopausal" symptoms, was found to have a large pelvic mass on physical exam. Computed tomography of the pelvis led to an incorrect diagnosis of malignancy, while radionuclide imaging using Tc-99m sulfur colloid confirmed the diagnosis of ectopic splenomegaly.

Choristoma↗
PubMed1991

Quantitative I-123-IMP brain SPECT and neuropsychological testing in AIDS dementia.

We performed I-123-IMP SPECT brain imaging on seven mildly demented AIDS patients and seven normal subjects. In an attempt to detect and quantitate regions of decreased I-123-IMP uptake, pixel intensity histograms of normalized SPECT images at the basal ganglia level were analyzed for the fraction of pixels in the lowest quartile of the intensity range. This fraction (F) averaged 17.5% (S.D. = 4.6) in the AIDS group and 12.6% (S.D. = 5.1) in the normal group (p less than .05). Six of the AIDS patients underwent neuropsychological testing (NPT). NPT showed the patients to have a variety of mild abnormalities. Regression analysis of NPT scores versus F yielded a correlation coefficient of .80 (p less than .05). We conclude that analysis of I-123-IMP SPECT image pixel intensity distribution is potentially sensitive in detecting abnormalities associated with AIDS dementia and may correlate with the severity of dementia as measured by NPT.

AIDS Dementia Complex↗
PubMed1991

Correlation of technetium-99m-DISIDA hepatobiliary studies with biopsies in liver transplant patients.

We compared 76 99mTc-DISIDA hepatobiliary studies with corresponding liver biopsies in 36 liver transplant patients to determine the histopathologic abnormalities that corresponded to scintigraphic abnormalities in uptake and excretion. Uptake was judged normal if the cardiac blood pool was barely visible or invisible on the ten minute image. Excretion was judged normal if images subsequent to the 15-min image showed a subjectively normal rate of decreasing parenchymal intensity. Biopsies were graded subjectively for hepatocyte damage and for findings of cholestasis. Uptake criteria were successful in differentiating high from low hepatocyte damage scores (p less than 0.0001), and excretion criteria were successful in differentiating high from low cholestasis scores (p = 0.002), while uptake criteria were not capable of differentiating high from low cholestasis scores, nor were excretion criteria capable of differentiating high from low hepatocyte damage scores (p's greater than 0.05). These results suggest that scintigraphy can distinguish intrahepatic cholestasis from pure hepatocyte damage.

Biopsy, Needle↗
PubMed1990

Perfusion thallium imaging of type I diabetes patients with end stage renal disease: comparison of oral and intravenous dipyridamole administration.

Eighty patients with type I diabetes and end stage renal disease were prospectively evaluated for coronary artery disease with dipyridamole-thallium-201 scintigraphy and quantitative coronary angiography. Forty patients received dipyridamole orally, and 40 received it intravenously. The prevalence of coronary artery disease was 53%. There were no significant differences in the accuracy of the two dipyridamole tests (sensitivity = 85%, specificity = 85%, accuracy = 85% for the oral group; sensitivity = 86%, specificity = 72%, accuracy = 79% for the intravenous group). Combining the 80 patients into a single group gave a sensitivity of 86%, a specificity of 79%, and an accuracy of 83% for the detection of coronary disease. Although the accuracy of this test in this patient population was similar to that previously reported for other groups, the prevalence of disease was high and resulted in a low predictive value of a negative test (83%).

Administration, Oral↗
PubMed1990

Therapeutic embolization: enhanced radiolabeled monitoring.

Radiolabeling of Ivalon (polyvinyl alcohol sponge) particles permits localization of injected particles during embolization through the use of a portable gamma camera and provides a means to prevent potentially fatal complications such as pulmonary embolization. A more efficient technique of labeling Ivalon particles with technetium-99m sulfur colloid was developed. An increase in labeling efficiency allowed more accurate determination of the distribution of injected Ivalon particles. Scanning electron microscopy demonstrated the stability of the Ivalon particles during this new labeling process. Two patients with arteriovenous malformations underwent therapeutic embolization with radiolabeled Ivalon particles; gamma camera imaging of the lesion and chest was performed throughout the procedure.

Adult↗
PubMed1989

Clinical efficacy of 99mtechnetium mercaptoacetylglycine kit formulation in routine renal scintigraphy.

99mTechnetium mercaptoacetylglycine is a promising new renal radiopharmaceutical undergoing phase III trials in the United States. In a preliminary investigation of the efficacy and safety of mercaptoacetylglycine in 30 adult patients with suspected renal disease we used simultaneous imaging with orthoiodohippurate as the physiological "gold standard". Of these patients 11 had undergone renal transplantation. Factors, such as time to peak renal activity, clearance half-life and regional functional comparison, were similar by orthoiodohippurate and mercaptoacetylglycine imaging. Visual and quantitative analysis of angiograms and renograms was markedly facilitated with the use of mercaptoacetylglycine. Several morphological abnormalities were apparent only during mercaptoacetylglycine evaluation. No adverse effects, changes in vital signs or significant changes in clinical laboratory status were encountered. Since mercaptoacetylglycine combined an excellent technetium image with the pharmacokinetics of orthoiodohippurate, mercaptoacetylglycine may supplant all other agents for routine clinical use.

Adult↗
PubMed1989

An improved radiolabeling technique of ivalon and its use for dynamic monitoring of complications during therapeutic transcatheter embolization.

Transcatheter embolization by Ivalon particles for treatment of arteriovenous malformations has been an accepted therapeutic technique for many years. We describe a new and efficient radiolabeling technique of Ivalon particles using [99mTc]sulfur colloid. Continuous and dynamic monitoring of injected radiolabeled Ivalon particles is made possible by viewing the persistence scope of a portable gamma camera whose head is positioned over the patient undergoing therapeutic embolization. Therefore, if inadvertent pulmonary embolism or reflux migration of radiolabeled Ivalon particles has occurred, the angiographer is immediately aware of this potentially serious or fatal complication and can take corrective action. We describe two patients, each with an arteriovenous malformation, who had therapeutic embolization with radiolabeled Ivalon particles, one resulting in reflux migration and the other resulting in inadvertent pulmonary embolism.

Adult↗
PubMed1989

Technetium-99m sulfur colloid spleen imaging following partial pancreatectomy and splenic artery and vein resection.

We retrospectively studied the records and [99mTc]sulfur colloid (TSC) spleen studies of 38 patients who underwent distal pancreatectomy with splenic artery and vein resection for donation to HLA-compatible relatives. The spleens in immediate postoperative TSC studies were normal in 11% of cases, showed no uptake in 16%, showed diffusely decreased uptake in 50%, and showed focal defects in 26%. Twenty of the patients, all with abnormal initial TSC studies, had repeat studies 2 wk to 3 yr later; 15% showed no change, 35% showed some improvement, and 45% became normal. One of six patients with no TSC uptake required splenectomy 2 days after pancreatectomy for splenic infarction. These data suggest that the spleen usually survives splenic artery and vein resection. Absent splenic TSC uptake raises the possibility of splenic infarction.

Adult↗
PubMed1986

Pancreatic sonography: enhancement by metoclopramide.

Abdominal sonograms were obtained before and after intravenous metoclopramide administration in 25 patients with a wide variety of abdominal complaints. Visualization of the pancreas was improved by this pharmacologic treatment in 44% of those patients in whom gas obscured the pancreatic bed. There was no improvement when fat was the primary prevention of visualization of the pancreas. There were no significant side effects of metoclopramide administration.

Adipose Tissue↗
PubMed1980

Delayed and recurrent intracranial hematomas related to disseminated intravascular clotting and fibrinolysis in head injury.

Twelve delayed or recurrent intracranial hematomas were seen in 340 patients with head injuries. Eleven of these hematomas were associated with clotting abnormalities suggesting disseminated intravascular clotting and fibrinolysis (DICF). Seven of 8 delayed traumatic intracerebral hematomas were associated with clotting abnormalities. Two of these were at ventriculostomy sites, which suggests an increased risk of bleeding in association with the insertion of ventricular catheters in patients with DICF. There were 2 delayed epidural hematomas, 1 under a fracture and the other on the side opposite a craniotomy that had been made to treat an intracerebral hematoma, and there were 2 postoperative epidural hematomas. No postoperative hematomas occurred in the absence of DICF. DICF is a major factor in the development of delayed and recurrent intracranial hematomas in patients with head injuries.

Brain Injuries↗
PubMedDate not supplied

Arteriohepatic dysplasia (Alagille's syndrome): unusual hepatic architecture and function.

BACKGROUND: Alagille's syndrome, also called arteriohepatic dysplasia, is a congenital anomaly consisting of hepatic, ocular, skeletal, and cardiac anomalies. The abdominal imaging findings were reviewed in eight patients with biopsy-proven Alagille's syndrome. One patient also had coexistent hepatocellular carcinoma. METHODS: Seven right upper quadrant sonograms, six hepatic CT studies, five hepatobiliary imaging studies, two hepatic MRI examinations, and two sulphur colloid liver spleen radionuclide studies were reviewed. RESULTS: The most striking abnormality was gross distortion of hepatic architecture. Five patients (63%) had marked external hepatic contour abnormalities, usually with either the entire liver or lobe having a predominately spherical shape. The portal vein was displaced by the spherical parenchymal component in four cases. Three other patients demonstrated marked hepatomegaly with no external contour abnormality. Hepatobiliary imaging studies demonstrated markedly prolonged excretion of the radiopharmaceutical in three of four patients examined. CONCLUSIONS: A diagnosis of Alagile's syndrome is suggested when a large, deformed and somewhat spherical liver is encountered, especially when hepatobiliary imaging studies demonstrate delayed excretion of radiopharmaceutical.

Adolescent↗