67Ga-citrate uptake by the parotid glands in sarcoidosis.

Bilateral accumulation of 67Ga-citrate by the parotid glands was observed in 9 of 27 patients (33%) with sarcoidosis and in a subgroup of 12 with systemic symptoms such as fever or clinically acute, progressive disease (75%). Asymptomatic patients or those with probable sarcoidosis associated with hilar and/or paratracheal adenopathy will not have parotid uptake. Similarly, uptake seldom occurs in normal patients or in those with untreated lymphoma or Hodgkin disease. If other inflammatory or granulomatous processes such as tuberculosis can be excluded, and if there is no history of head and neck irradiation, then this finding in acutely ill patients suggests sarcoidosis.     

Diagnosis of uveo-parotid fever by 67Ga-citrate imaging

67Ga-citrate scan from skull to mid-abdomen showed increased uptake in both parotid glands, mediastinum, lungs, uvei and/or enlarged lacrimal glands. The differential diagnosis of the positive radiogallium scan is discussed with emphasis on the value of the extrathoracic findings. Tissue diagnosis confirmed the imaging diagnosis of sarcoidosis. The case illustrates the usefulness of double radionuclide study--67Ga and 99mTc-MAA--and of the tomographic scanner in defining the spread of the active granulomatous disease.     

Possible enhancement of 67Ga-citrate imaging by iron dextran.

The whole-body retention of 67Ga-citrate was studied in intact and in abscess-bearing rabbits. The abscess-to-muscle ratio was obtained using a data processor. Administration of iron dextran lowers the whole-body retention in both the intact and abscess-bearing animals. The optimum time for administering the iron dextran was 24 hr after the 67Ga-citrate injection. At this time, the abscess-to-muscle ratio was highest and the cathode-ray screen images showed lowered back-ground activity and much better definition of the lesion.     

Gallium-67 imaging in muscular sarcoidosis

A case is presented of sarcoid myopathy in which radiogallium was seen to accumulate in the sites of muscle involvement. Uptake of the radiotracer disappeared following institution of corticosteroid therapy. The exceptional nature of this case contrasts with the high frequency of biopsy evidence of sarcoid muscle disease but is consistent with the rarity of clinical evidence of sarcoid granulomas in muscle. Gallium-67 imaging can be used to determine the extent of muscle involvement and, through evaluation of uptake intensity, the degree of disease activity before and after treatment.     

Distribution of 67Ga-citrate in abscess-induced rat by quantitative whole body autoradiography

Distribution of ⁶⁷Ga-citrate in inflammatory tissues was determined, and correlation between the ⁶⁷Ga-uptake and capillary permeability of plasma from blood vessels in the inflammatory tissue was elucidated, by quantitative whole body autoradiography and double tracer autoradiography.The distribution of ⁶⁷Ga in inflammatory tissue was similar to that of ¹³¹I-HSA and ^99mTc-HSA, which were applied as an index to the plasma element. These results showed that the capillary permeability of plasma from blood vessels in the inflammatory tissue increases, and this causes the ⁶⁷Ga-uptake.     

Muscular sarcoidosis: Ga-67 scintigraphy and magnetic resonance imaging

Ga-67 scintigraphy is helpful in the assessment of active extrapulmonary sarcoidosis. Muscular involvement of sarcoidosis is often asymptomatic or nonspecific, and laboratory examinations do not provide convincing evidence of muscular involvement. The authors report a case of muscular sarcoidosis detected by Ga-67 scintigraphy. In a patient who had fever and arthralgia of both knee joints, Ga-67 scintigraphy showed mediastinal and hilar involvement of sarcoidosis with unexpected extensive muscular uptake. Magnetic resonance imaging revealed in detail intramuscular infiltration of sarcoid granuloma. Ga-67 scintigraphy is useful in detecting inflammatory muscular involvement of sarcoidosis and other multiorgan involvement.     

Lymphoscintigraphy by SC injection of 67Ga-citrate

Lymphoscintigraphy with SC injection of ⁶⁷Ga-citrate was carried out on patients with lymph node metastasis and malignant lymphoma. The dose given at each injection site was about 200 Ci and scintigraphy was started about 5 min after injection. Metastatic lymph nodes and malignant lymphoma were successfully imaged. This positive delineation corresponded well to cold lesions detected by lymphoscintigraphy with ^99mTc-rhenium colloid in metastatic lymph nodes. Hotter lesions in malignant lymphoma were scanned positively with ^99mTc-rhenium colloid by this method. In in vitro studies, incorporation of ⁶⁷Ga-citrate in HeLa S3 cells was about 4 times that in macrophages, when the incubation time was 1 h, while colloidal uptake by macrophages was 13 times that by HeLa S3 cells. The binding of ⁶⁷Ga to transferrin in lymph and pinocytosis are suggested mechanisms of localization. A combination of colloid-and sc ⁶⁷Ga-lymphoscintigraphy would be of value in the diagnosis of lymph node disease.