Gallium-67-citrate scanning of renal parenchymal malacoplakia.

UNLABELLED: The purpose of this article is to review the potential role of nuclear medicine scanning, especially with 67Ga, in the presumptive diagnosis and clinical management of patients with renal parenchymal malacoplakia (RPMP), a rare disease associated with coliform bacterial infection of the kidney and characterized by chronic unresolving inflammatory infiltrates containing von Hansemann macrophages in the renal parenchyma. METHODS: Published cases of RPMP were collected from the archival literature by searching the MEDLINE database and by reviewing bibliographic references contained in articles on malacoplakia. Data on the clinical features and radiographic evaluation of patients with RPMP were extracted from the clinical case reports. RESULTS: Forty-three cases of RPMP published over the past 20 yr were identified. Ten of the 43 patients (23%) had 67Ga scanning as a component of their diagnostic evaluation. In all 10 patients, renal uptake of 67Ga was classified as intense. Two of those 10 patients had serial 67Ga scanning performed to assess response to antibiotic treatment; both patients exhibited decreased uptake or complete resolution of abnormal renal uptake over time, a finding also exhibited by our patient. CONCLUSION: Intense renal uptake of 67Ga, typically in the clinical setting of fever, progressive renal failure and nephromegaly, strongly supports a diagnosis of RPMP. In those patients receiving prolonged antimicrobial therapy for RPMP, resolution of abnormal 67Ga uptake over time may provide an objective endpoint for treatment.

Technetium-99m-sestamibi SPECT localization of mediastinal parathyroid adenoma.

We report a case in which 99mTc-sestamibi SPECT was used to localize a middle mediastinum parathyroid adenoma that was not detected with planar sestamibi imaging on two previous occasions. Despite prior surgical exploration of the neck and mediastinum, the patient had a 20-yr history of hyperparathyroidism.

Imaging of transplanted parathyroid tissue in a patient with recurrent hyperparathyroidism.

Parathyroid scintigraphy is useful in detecting residual hyperplastic parathyroid tissue in patients who continue to have hyperthyroidism after "total parathyroidectomy." Typically, only the neck and mediastinum are imaged. The authors report a case in which images of the forearm were helpful in detecting hyperplastic autologous transplanted parathyroid tissue.

Scintigraphic findings in renal malakoplakia.

The scintigraphic findings in a rare case of bilateral renal malakoplakia are presented. Markedly increased Ga-67 activity was present in both kidneys in sites corresponding to focal cortical defects on Tc-99m gluceptate (glucoheptonate) imaging. Interestingly, there was no abnormal renal activity with In-111 leukocyte scanning.

Tc-99m sestamibi for detection of parathyroid adenoma. Comparison of single and dual tracer imaging.

Single and dual radionuclide techniques have been described in localization of parathyroid adenomas. Although single radionuclide imaging with Tc-99m sestamibi has many advantages, it can fail to demonstrate a parathyroid adenoma, which, in the case presented, is well demonstrated with dual radionuclide imaging. The authors recommend dual tracer imaging when searching for parathyroid adenoma.

Detection of medullary carcinoma of the thyroid with I-131 MIBG.

Imaging with I-131 MIBG has proved useful for the detection of pheochromocytoma, neuroblastoma, and other neoplasms of neural crest origin. The authors present a case of a patient who was initially diagnosed as having follicular carcinoma of the thyroid in which I-131 MIBG played a key role in leading to the diagnosis of medullary carcinoma of the thyroid. Local and distant metastases were detected using I-131 MIBG imaging. Uptake of I-131 MIBG by medullary carcinoma of the thyroid has both diagnostic and therapeutic implications.

Conventional radionuclide cardiac imaging.

For more than two decades, conventional radionuclide techniques have been employed for the noninvasive evaluation of cardiac function. Standardized techniques have been developed and are widely available. Extensive clinical experience has confirmed the reliability of these techniques and has established important roles in providing diagnostic and prognostic information. Conventional radionuclide cardiac imaging currently emphasizes the demonstration of abnormalities in myocardial perfusion and ventricular function. Myocardial and radionuclide studies are infrequently employed but can offer helpful information in specific clinical situations.

Mediastinal uptake of I-131 in a hiatal hernia mimicking recurrence of papillary thyroid carcinoma.

I-131 is used to image patients diagnosed with papillary or follicular carcinoma of the thyroid after thyroidectomy to observe for metastatic disease or residual thyroid tissue. I-131 is excreted in gastric mucosa and is seen in the esophagus after the swallowing of saliva. The authors describe a patient in whom radiopharmaceutical activity in the mediastinum was subsequently shown to be due to a hiatal hernia.

False-positive radionuclide hepatobiliary imaging following cystic duct stone removal.

The authors report a case in which a radionuclide hepatobiliary image was falsely indicative of cystic duct obstruction in a patient with an indwelling cholecystostomy tube and an externalized gallbladder-duodenal stent. Cystic duct patency was demonstrated radiographically shortly before and after the radionuclide study. The authors recommend that cystic duct obstruction indicated by a radionuclide hepatobiliary image be confirmed by another means if a cholecystostomy tube is present, or if the patient recently has undergone percutaneous gallbladder or cystic duct manipulations.

Radioiodide imaging of struma cordis.

This is the first reported case in which struma cordis was demonstrated with radionuclide imaging. A 56-year-old white woman underwent surgical excision of a benign intracardiac thyroid mass (struma cordis). Subsequent radionuclide imaging with I-123 sodium iodide and Tc-99m labeled red blood cells demonstrated a normal cervical thyroid gland as well as a focus of activity in the mediastinum consistent with intracardiac thyroid.

Thyrotoxicosis caused by functioning metastatic thyroid carcinoma. A rare and elusive cause of hyperthyroidism with low radioactive iodine uptake.

A patient with progressively worsening thyrotoxicosis, refractory to medical therapy, is described. Repeated measurements of thyroidal RAI uptake over a 13 month period were low consistently and could not be explained by iodine ingestion, thyroiditis, or administration of exogenous thyroid hormone. An I-131 scan ultimately revealed striking activity at the base of the skull, reflecting ectopic excessive production of thyroid hormone by a solitary functioning metastatic thyroid carcinoma. The thyrotoxic state resolved after large doses of therapeutic I-131. Typical features of this rare cause of hyperthyroidism are discussed.

Urinoma detected by dual isotope renogram-cystogram.

A case is reported in which a urinoma developed following a renal transplant. Dual isotope renography-cystography using Tc-99m DTPA and Ga-67 citrate revealed the diagnosis after ultrasonography and radiographic cystography were nondiagnostic.

Relationship of radionuclide liquid bolus transport and esophageal manometry.

Using simultaneous esophageal manometry and radionuclide transit studies, we compared liquid bolus transport with the various parameters of esophageal contractions. Study subjects included seven normal individuals, six patients with the "nutcracker esophagus" (mean distal peristaltic amplitude greater than 180 mm Hg), and three patients with spastic motility disorders. Manometric studies were performed when the subjects were in the basal state and after intravenous administration of edrophonium and atropine. Simultaneous radionuclide studies were done with subjects in the supine position by swallows of 250 mu Ci technetium Tc 99m sulfur colloid in 10 ml water. We found that normal liquid bolus transport (less than 15 seconds) is primarily dependent on the presence of a peristaltic wave front throughout the esophagus. Above a threshold pressure of 30 mm Hg, liquid transport was not affected by amplitude (33 to 500 mm Hg) or duration (3 to 15 seconds) of esophageal contractions. Repetitive wave forms also gave normal transit times as long as the wave front was peristaltic in onset. There was a significant inverse correlation (-0.65; P less than 0.001) between liquid transit time and peristaltic velocity. Prolonged radionuclide transport (30 to less than 50 seconds) was observed only with nonperistaltic contractions and very low amplitude (15 to 30 mm Hg) peristaltic waves.

Hematologic depression following therapy with strontium-89 chloride.

Initial clinical trials using strontium-89 (Sr-89) chloride for the treatment of painful skeletal metastases have observed minimal or no hematological depression secondary to the radiostrontium. A patient with marked bone marrow depression temporally related to the administration of the Sr-89 is reported, and the need for close hematological monitoring is emphasized. Bone marrow tumor replacement may predispose patients to marrow depression from radiostrontium, and such patients should be treated with caution.

Conventional radionuclide brain imaging in the era of transmission and emission tomography.

The clinical applications for conventional radionuclide brain imaging have declined considerably since the introduction of newer imaging modalities (computerized cranial tomography [CCT], nuclear magnetic resonance [NMR]). Currently, conventional brain imaging primarily serves as a complementary test when CCT is negative or equivocal and strong clinical suspicion remains. Selected areas in which radionuclide imaging may be the preferred modality include evaluation of cerebral perfusion in assessment of brain death, detection of early viral encephalitis, evaluation of major venous sinus patency, external marking for localization of intracranial tumor, and in selected cases of suspected subdural hematoma, brain tumor, and cerebrovascular disease. The concept of conventional radionuclide brain imaging will likely undergo considerable change in the near future as newer radiopharmaceuticals are introduced and wider application is made of single photon emission computerized tomography (SPECT) and positron emission tomography (PET) imaging.

The utility of adrenal scintigraphy in Cushing's syndrome and hyperaldosteronism.

Thirty-three adrenal scintigrams in 30 patients were reviewed to determine the utility of this noninvasive imaging technique. It was found to be very accurate in distinguishing bilateral from unilateral hyperfunction in patients who have clinical and biochemical evidence of adrenal cortical hyperfunction. The technique proved correct in 12 of 12 cases of Cushing's syndrome and 14 of 19 cases of hyperaldosteronism. Specific clinical questions were also answered in three miscellaneous cases.