Paul E. Fisher

Iodinated nanoparticles for indirect computed tomography lymphography of the craniocervical and thoracic lymph nodes in normal dogs.

RATIONALE AND OBJECTIVES We evaluated the imaging characteristics of an interstitially or intraperitoneally delivered iodinated particulate contrast agent for computed tomography (CT) lymphography of the craniocervical and thoracic lymph nodes. METHODS We injected 2-4 ml of 15% wt/vol iodinated nanoparticle suspension subcutaneously, submucosally, or intraperitoneally in eight normal dogs. CT and plain radiographic images were obtained prior to contrast administration and 4 hr, 24 hr, and 7 days after injection. Correlation was made to detailed postmortem assessment. RESULTS CT images showed enhancement of regional nodes draining injection sites. Mean attenuation of opacified nodes was 313 +/- 297 (mean +/- standard deviation), 536 +/- 453, and 492 +/- 372 Hounsfield units at 4 hr, 24 hr, and 7 days postinjection, respectively. Lymph node opacification on CT images correlated well with node location found at postmortem. CONCLUSION Craniocervical and thoracic lymph nodes can be effectively opacified from interstitial or intraperitoneal delivery of this iodinated nanoparticulate contrast agent.

Radiographic determination of the anatomic hip joint center: A cadaver study

We studied 31 human pelvic cadaver specimens with 57 intact hip joints. The teardrop, which represents the inferior portion of the acetabular notch, was identified as also was the center of rotation in the articulating femoral head. The pelvic height and the horizontal and vertical distances between the acetabular notch and the hip joint center were measured. We found the center of rotation of the hip joint to be 13 percent of the pelvic height lateral and 7 percent of the pelvic height superior to the teardrop. No sex difference was found.

Lung clearance of 99mTc-DTPA aerosol in conscious sheep

This study was initiated to determine the rate and characteristics of 99mTc-DTPA clearance from the whole lung in a group of 9 sheep. Submicronic aerosol droplets were delivered to unsedated sheep held in a sling-like frame. Best fits for clearance curves to single- and biexponentials were calculated. The monoexponential T50 for the aerosol clearance was 293 min +/- 74 SD. Background correction was found to have a minimal effect (approx. 10%). Biexponential fitting only marginally improved correlations in the 8 healthy sheep, but in one additional animal with clinical evidence of pneumonia, clearance was faster and biexponential fitting was substantially better. These clearance values in conscious sheep are longer than previous findings with 99mTc-DTPA in anesthetized sheep. There appears to be a wide variation of radioaerosol 99mTc-DTPA lung clearances among different species, sheep exhibiting a comparatively prolonged clearance profile.

Ozone-induced accelerated lung clearance of 99mTc-DTPA aerosol in conscious sheep

This study was initiated to determine the rate and characteristics of 99mTc-DTPA clearance from the lungs of unanesthetized sheep exposed to varying concentrations of O3 for 4 h in a whole-body exposure chamber. Four sheep exposed to 1 ppm O3 had a monoexponential T50 of 274 +/- 81 min (SD), not significantly different from sham exposures (316 +/- 150); 5 sheep exposed to 2 ppm had a T50 of 234 +/- 101 min, not significantly different from sham exposures (364 +/- 131 min). Five additional unanesthetized sheep exposed to 2 ppm for 4 h via a nasotracheal tube had a T50 of 192 +/- 55 min, significantly different from sham exposures (300 +/- 96 min). The results show that the effect of oxidant pollutants on the permeability of alveolobronchiolar epithelium may be assessed in conscious sheep.