Rene P. duCret

Evaluation of the gastric retention properties of a cross-linked polymer coated tablet versus those of a non-disintegrating tablet

Abstract The gastric emptying time of tablets coated with a cross-linked polymer that enabled them to balloon and float in gastric media has been compared with that of uncoated, non-disintegrating tablets in both fasted and fed states, with healthy human volunteers using gamma camera scintigraphy. In the fed state, the balloon tablets prolonged the gastric emptying time by an average of 6 h over that of the uncoated tablets. The emptying times for both coated and uncoated tablets were much shorter in the fasting state. The balloon tablet did not significantly prolong the gastric emptying time in the fasted state.

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.

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 > 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.

CT evaluation of atypical hepatic fatty metamorphosis

Focal fatty metamorphosis of the liver is a well-recognized entity characteristically demonstrated by a nonspherical, low-density area without mass effect. We present a case of focal fatty metamorphosis of the liver that shows multiple areas of low attenuation within the liver with mass effect. Radionuclide liver-spleen scan shows multiple focal defects corresponding to the areas of fatty metamorphosis.

Reverse mismatch between perfusion and aerosol ventilation in transplanted lungs

Thirty ventilation-perfusion pulmonary scintigraphic studies were performed in 13 patients who had undergone unilateral lung transplantation. Ventilation–perfusion mismatch (ventilation better than perfusion) was judged absent, mild, moderate, or severe in the transplanted and native lungs. Ventilation-perfusion mismatch was significantly worse in the transplanted lungs (p<.0001). Findings of lung biopsies and chest roentgenograms failed to correlate with the severity of ventilation-perfusion mismatch. Hypoxic pulmonary vasoconstriction appears to be significantly impaired in most unilateral lung transplants; the mechanism for this impairment is unclear.

Comparison of Tc-99m DTPA aerosol ventilation studies with pulmonary function testing in cystic fibrosis

In 43 patients with cystic fibrosis, the results of 122 Tc-99m DTPA aerosol ventilation (DAV) studies were compared with pulmonary function tests (PFTs) that were performed within 24 hours of the DAV studies. The DAV studies were evaluated blindly for (A) number of pulmonary segments showing little or no ventilation, (B) number of foci of bronchial deposition of aerosol, and (C) subjective overall improvement, lack of change, or worsening from the previous study. (A) and (B) correlated significantly with all PFTs (ps < .001, rs = -.51 to -.73). Changes in (A) and (B) also correlated with changes in PFTs (ps ≤ .001, rs = -.37 to -.58). The three populations in (C) were significantly different from each other with respect to changes in all PFTs (p ≤ .002). Intervals between studies showing subjective improvement, no change, and worsening averaged 60, 133, and 306 days, respectively. These results suggest that DAV is an indicator of both regional and global pulmonary function and may be useful in evaluating patients with cystic fibrosis.

Ectopic splenomegaly in Felty's syndrome.

A 50-year-old woman with Feltys 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.

ALTERNATIVE DESIGN FOR RADIOLOGIC GUIDANCE IN VIDEO THORACOSCOPIC SURGERY

RATIONALE AND OBJECTIVES.Easy dislodgment and a pneumothorax rate of up to 50% have been reported with the use of mammographic hookwires for radiologic guidance in thoracoscopic surgery. An alternative design is described and preliminary in vitro results are reported. METHODS.The new design is based on the T-fastener used in percutaneous gastrostomies and can be deposited with a 20-Fr guidance needle. In vitro measurements of the anchoring capability of this design were compared with the anchoring capability of the Hawkins III (Meditech/Boston Scientific, Watertown, MA) mammographic hook wire system. RESULTS.Anchoring capabilities of the alternative anchoring design and the Hawkins III mammographic hook wire localization system are comparable. Complete dislodgement of both anchors occurs at approximately 350 gm. CONCLUSIONS.Preliminary in vitro investigation demonstrated similar anchoring capabilities of the new design and mammographic hook wires. Potential advantages of this suture-based localization device over hook wires are discussed.