Comparison of CT and MRI in the evaluation of therapeutic response in thoracic Hodgkin disease.

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.

Tropical pyomyositis. Demonstration of extent and distribution of disease by gallium scintigraphy.

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.

Lymphoma of the mediastinum and neck: evaluation with Ga-67 imaging and CT correlation.

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.

Renal effects of percutaneous stone removal.

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.

Gallium scanning in lymphoid interstitial pneumonitis of children with AIDS.

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.

The noninvasive diagnosis of intrathoracic splenosis using technetium-99m heat-damaged red blood cells.

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.

111Indium-tropolone labeled human PMNs: a rapid method of preparation and evaluation of labeling parameters.

Pure polymorphonuclear leukocytes (PMNs) have been isolated from a small amount of human blood by a single-step density gradient centrifugation method using a commercially available Ficoll-Hypaque mixture of density 1.114. The cells were labelled with [111In]tropolone in both buffer and plasma. Cell viability, ability to generate superoxide anion, and chemotaxis were found to be unaltered both before and after labeling. The optimum tropolone concentration for labeling was found to be 1 X 10(-4) M. Labeling efficiency was higher at 37 degrees C than at room temperature. Compared to [111In]oxine, tropolone preparation both in buffer and plasma resulted in consistently higher yields. Preliminary experiments of in vivo cell viability of the labeled PMNs were carried out in rabbits. The ability of the cells to localize in experimentally produced inflammatory lesions was found to be intact. The method of cell separation and labeling described has been found to be simple and rapid and could easily be incorporated in routine nuclear medicine laboratory practice.

Morphologic and functional changes in the kidney after percutaneous nephrosto-lithotomy.

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.