Current imaging modalities are accurate in establishing the diagnosis and extent of thoracic Hodgkin disease. After treatment, however, it is extremely difficult to differentiate potential residual active neoplastic disease from scar tissue, or identify early recurrence. We evaluated the contribution of MRI in the assessment of the response to treatment of thoracic Hodgkin disease in the assumption that scar formation would be characterized by low signal intensity in all pulse sequences, whereas active tumor should maintain a degree of high signal intensity on T2-weighted images. In 47 occasions (23 patients) both CT and MRI were able to identify correctly active disease, but had low specificity in confirming remission because of residual tissues masses. High signal intensity on T2-weighted MR images often persisted despite remission, probably because of edema, necrosis, granulation or other factors. MRI was somewhat more specific than CT and may be quite valuable to confirm remission in patients with residual masses that no longer appear hyperintense on T2 after treatment.

The role of gallium-67 in the differentiation between active disease and fibrotic changes in patients with childhood lymphoma involving the mediastinum and neck was evaluated prospectively. Ga-67 imaging and computed tomography (CT) were correlated with clinical findings at the time of initial presentation and follow-up in 19 patients. Both modalities enabled detection of active disease on all occasions, but CT results were false-positive for residual disease in 10 patients (53%), whereas Ga-67 imaging results were false-positive in only one patient (5%). Neither modality, however, proved accurate in patients with rebound thymic hyperplasia. Ga-67 imaging is a useful tool for assessing response to therapy in children with lymphoma of the mediastinum and neck.

Pyomyositis is a Staphylococcus aureus infection of muscles reported primarily in tropical countries but seen with increasing frequency in temperate climates. Because of its rarity in the United States, the diagnosis may not be considered immediately, and involved muscles may break down and become abscessed. Diagnosis is most reliably made by the recovery of pus from a muscle aspirate. Ga-67 scan findings of an interesting case of pyomyositis involving many muscle groups in both upper and lower extremities is reported. Despite arthralgias and complicating adult respiratory distress syndrome, Ga-67 correctly localized the infection to muscles in the shoulders, upper thorax, buttocks, and thighs. A bone scan was negative, excluding the possibility of extension of the infection to bone.

Preoperative and postoperative renography with 99mTechnetium-diethylene-triamine pentaacetic acid was performed on 33 patients who were free of renal scarring, infection, and obstruction and who underwent percutaneous renal stone removal. Although there was a transient decrease in renal function postoperatively in some patients, statistically significant reductions in renal function occurred only in 1 patient with an arteriovenous malformation that was embolized and in 1 patient who had a postoperative ureteropelvic junction stricture. The creation of more than one nephrostomy tract did not affect the results. In the absence of serious complications, percutaneous nephrostomy does not have a significant effect on renal function.

Intrathoracic splenosis results from the implantation of splenic tissue in the thoracic cavity following simultaneous rupture of the spleen and diaphragm. These implants may form mass lesions that lead to an extensive, costly, and invasive series of investigations, usually resulting in unnecessary surgery. The key to diagnosis is a high index of suspicion provoked by the history of a traumatic event, possibly in the distant past. This report emphasizes that because of its ability to demonstrate the functional nature of tissue, a definitive diagnosis can be made using heat-damaged Tc-99m RBCs without the need for surgical intervention.

Lymphoid interstitial pneumonitis (LIP) is a frequent pulmonary complication in the child with the acquired immune deficiency syndrome (AIDS) and human immunodeficiency virus (HIV) infection. We report the gallium scan findings in two children with AIDS and LIP. Gallium scintigraphy in both children demonstrated increased radionuclide concentration throughout the lungs, a pattern indistinguishable scintigraphically from that of Pneumocystis carinii pneumonia (PCP). This should alert nuclear medicine practitioners and referring physicians to another cause of diffusely increased gallium uptake in the lungs of patients with AIDS.

Morphology and function of the kidney were studied before and after percutaneous stone extraction in 33 patients with unilateral calculus disease to assess damage secondary to the extraction procedures. Anatomic changes were studied using excretory urography before the procedure and at 3 to 6 months postoperatively, and using nephrostograms and noncontrast nephrotomograms several days after the procedure. Renal function was evaluated with radionuclide renography both before surgery and at either 4 to 6 weeks or about 1 year postoperatively. Six patients had early changes detected clinically and with nephrostograms, but only three of these had abnormalities on delayed excretory urography. Significant changes in renal function were found only in those patients who had clinically detectable complications (p less than 0.05), in one case before symptoms were manifest.

A simple and practical automatic device was designed and built to provide calibrated doses of radiopharmaceuticals into a syringe without the need for handling the radioactivity unnecessarily. Each radiopharmaceutical dose is loaded within the currently available calibration chamber and the amounts adjusted according to the accuracy of the commercial calibrators. This system consists of a small and compact unit which fits within the central cavity of the ionization chamber of the Capintec Radioisotope Calibrator CRC-4. At the base of the device is a lead shielded receptacle for a vial or a reservoir of radiopharmaceutical. The empty syringe is lowered into the central region of the ionization chamber where connection with the radiopharmaceutical supply reservoir is completed. A servo-motor adjusts the syringe plunger until the required quantity of radioactivity is loaded into the syringe. The amount of radioactivity in the loaded syringe is constantly displayed on the digital indicators of the calibrator. Once the proper quantity of radioactivity is loaded, the syringe is uncoupled and withdrawn between two halves of a lead shield. Radiopharmaceutical volume is indicated on the plunger rod. The use of translucent needle hubs permits the visualization of both blood and air when an intravenous injection is accomplished.more » This method reduced the radiation exposure and the need to handle the radioactive materials necessary for calibration of each dose. All operations occur within the ionization chamber of the dose calibrator minimizing radiation exposure to personnel.« less

The percutaneous removal of renal calculi is a relatively new technique which may significantly decrease the morbidity due to calculous disease of the upper urinary tract. Over two hundred such procedures have been performed in our institution over the last two years. The authors have designed a prospective study of fifty patients with non-obstructing calculi referred for percutaneous nephrolithotomy in order to determine if there is any functional change of the kidney secondary to the operation itself. Each patient is studied using a standard Tc99m DTPA renogram and computer assisted analysis both before and four to six weeks after surgery. In order to make the selection of regions of interest (ROIs) as reproducible as possible, the ROI of the entire kidney is selected on a frame early in the study, and later frames are used to outline the collecting system. Using subtractive techniques, the contribution of the cortex of the side to be operated upon to total cortical function is derived from the previously defined regions. Renogram curves are drawn for the entire kidney as well as renal cortex. The analysis post-operatively is performed using the same ROIs generated on the pre-operative study. To date, the authors have studied twentymore » patients pre-operatively and followed up seven. A small but consistent decrease in renal function is seen post-operatively in both the entire kidney and cortex. A statistical analysis of the study group will be performed after further follow up and data processing of more patients.« less