Ga-67 uptake in the lung in sarcoidosis

Sarcoidosis in a chronic dialysis patient diagnosed by sarcoidosis-related hypercalcemia with no common systemic clinical manifestations: a case report and review of the literature

Sarcoidosis is a systemic granulomatous disease of unknown origin. We herein report a case of sarcoidosis in a chronic dialysis patient diagnosed by hypercalcemia without any common clinical manifestations. The onset of sarcoidosis in chronic dialysis patients is rare; to the best of our knowledge, only 23 cases have been reported. Evaluation of the 23 previously published cases revealed that a diagnosis of sarcoidosis was often achieved by the presence of sarcoidosis-related hypercalcemia without any common clinical presentations, as in the present case. This characteristic may arise from a specific immune deficiency and the unique physiology of 1,25-dihydroxyvitamin D3, a main cause of sarcoidosis-related hypercalcemia, in chronic dialysis patients. These clinical features may be useful to understand the pathogenesis of sarcoidosis.

Tumoral calcinosis associated with hypercalcemia in a patient with chronic renal failure

A 56-year-old male with chronic renal failure was admitted to the hospital because of progressive hip pain, appetite loss, general fatigue, and hypercalcemia. Slight pain had developed in the left hip 3 months before the initiation of hemodialysis, which subsequently developed into hyperalgesia. The patient was suspected to have sarcoidosis based on the elevated serum angiotensin-converting enzyme and lysozyme levels, and the ocular finding characterized by punched out chorioretinal scarring, although this could not be confirmed by histological evaluations. There was an abnormal uptake of gallium in the dependent portion of the tumoral calcinosis, which could have suggested either the presence of granulomatous sarcoid tissue within the calcified mass or active calcification associated with an inflammatory reaction. Elevated serum concentrations of 1,25-dihydroxyvitamin D3, which should be implicated in the development of hypercalcemia, promptly decreased after the administration of steroids. Steroid administration subsequently led to a decrease in the serum calcium and relief of the hip pain. This was a rare case of sarcoidosis associated with symptomatic tumoral calcinosis and hypercalcemia. The diagnostic significance of a gallium scan in this case will also be discussed.

[Pulmonary activity in sarcoidosis: 67Ga uptake quantification and plasma determination of 1,25-dihydroxyvitamin D)]

AIM

The aim of our study was to produce a quantitative determination of Ga-67 pulmonary intake and correlate it with plasma levels of calcitriol.

MATERIAL AND METHODS

A prospective study was conducted, and included 65 patients (29 female, 36 male) referred to our section due to suspected sarcoidosis or fibrosis of the lungs. Gammagraphic images were obtained after injecting Ga-67 citrate, and vitamin D was determined by IRMA method. The final diagnosis led to 4 groups of patients: 26 with active sarcoidosis; 5 with inactive sarcoidosis (4 with a previous gammagraphic study, included in the previous group); 8 with fibrosis of the lungs; and 30 patients with no demonstrable pathology following medical/instrumental examination. For the quantitative analysis, areas of interest were drawn around each lung, together with another region in soft tissue of the right shoulder (background). The geometric mean for each region was calculated, as well as the Ga intake rate (InGa = [lung activity-background]/background).

RESULTS

Significant differences were found (p<0.01) when comparing each group's InGa, with the highest values occurring in the active sarcoidosis group. No significant differences were found when comparing plasma levels of calcitriol. No significant correlation was demonstrated between hormone and InGa rates.

CONCLUSIONS

InGa would seem to be a useful parameter for assessing inflammatory activity in the parenchyma of the lungs. Perhaps as a result of their variability, plasma concentrations of the active vitamin D metabolite have a limited role in this assessment.

Gallium and other agents in diseases of the lung

The use of gallium for pulmonary diseases is hampered by its relative lack of specificity, typical 1- to 3-day delay between injection and imaging time, and suboptimal imaging characteristics. Other nuclear and nonnuclear imaging modalities, such as (18)F-fluorodeoxyglucose positron emission tomography (PET) and high-resolution chest computed tomography, have replaced gallium in many clinical algorithms. Yet gallium and other radiotracers, such as thallium, sestamibi, and labeled white blood cells, are useful in many specific clinical situations involving lymphoma and other neoplasias, inflammatory processes such as sarcoid and interstitial pneumonia, tuberculosis and other infections, and the acquired immune deficiency syndrome. Gallium and some of the other single-photon agents still have value in establishing a diagnosis, assessing the location and extent of disease, differentiating active disease from chronic scarring, guiding potential biopsy, and determining recurrence and response to therapy in patients with certain lung diseases, particularly when access to PET imaging is not available.

Sarcoidosis activity: correlation of HRCT findings with those of 67Ga scanning, bronchoalveolar lavage, and serum angiotensin-converting enzyme assay

PURPOSE

The objective of this study was to correlate the findings of sarcoidosis on high resolution CT (HRCT) with indexes of disease activity as measured with 67Ga scan, bronchoalveolar lavage (BAL), and serum angiotensin-converting enzyme (SACE) assay.

METHOD

Twenty-nine patients with proven sarcoidosis underwent HRCT scan, 67Ga scan, BAL, and SACE assay within a 1 month period. The extent of parenchymal involvement by nodules, consolidation, ground-glass attenuation, and linear opacities was quantified to the nearest 10% of surface area affected on the CT examination. Whole-lung gallium uptake was quantified and the percentage of BAL-recovered lymphocytes (BAL-%LC) and SACE levels obtained by chart review. CT scores of disease extent were correlated with measured indexes of activity using the Spearman rank correlation coefficient.

RESULTS

The mean extent of nodules, consolidation, ground-glass attenuation, and linear opacities on HRCT images was 15.1 +/- 16.6, 1.6 +/- 4.0, 17.5 +/- 25.4, and 7.6 +/- 9.6%, respectively. The extent of nodules and consolidation correlated with the intensity of lung gallium uptake (r = 0.46, p < 0.02), BAL-%LC (r = 0.50, p < 0.01), and SACE levels (r = 0.38, p < 0.05). No significant correlation was found between extent of ground-glass attenuation or linear opacities with any indexes of disease activity.

CONCLUSION

On HRCT scan, nodules and consolidation in sarcoidosis reflect disease activity as measured by 67Ga scan, BAL, and SACE assay.

Nuclear imaging. 67Gallium, 201thallium, 18F-labeled fluoro-2-deoxy-D-glucose positron emission tomography

67Gallium scan has been used for years in sarcoidosis as a marker of activity, a determiner of the extent and distribution of the disease, a diagnostic support, and an aid in therapeutic management. Because of its limited sensitivity and specificity for sarcoidosis, however, it is currently used mainly to assist in diagnosis in difficult cases, particularly in those with isolated extrathoracic sarcoidosis. The finding of the typical lambda or panda patterns supports the diagnosis and reinforces the indication to perform an appropriate biopsy or Kveim-Siltzbach test. In addition, the detection of clinically silent extrathoracic uptake may provide sites for biopsy. 67Gallium scans' routine use in the follow-up of pulmonary sarcoidosis under treatment has decreased because that is best accomplished by means of serial chest radiographs and PFT. 201Thallium scintigraphy studies the myocardial perfusion and is complementary to echocardiography and 24-hour electrocardiographic monitoring in the assessment of sarcoid cardiac involvement. It typically shows segmental areas of decreased uptake in the ventricular myocardium that disappear or decrease in size during stress or after intravenous administration of dipyridamole. That reverse distribution is not specific for cardiac sarcoidosis, however, because it may also occur in other cardiomyopathies. PET is based on the increase of glucose metabolism in inflamed tissues. It may have great potential to assess sarcoidosis activity, but it is still largely experimental and is not routinely employed.

Pulmonary uptake in 67-gallium citrate scintigraphy-the 'negative heart' sign

Diffuse pulmonary uptake in 67-gallium citrate (67-Ga) scintigraphy occurs in a large number of neoplastic and inflammatory conditions. Discrimination between normal and abnormal 67-Ga uptake over the chest can be difficult and a simple visual method for identifying abnormal studies is described. A series of 39 gallium scintigrams was retrospectively reviewed by the authors and reported without knowledge of the patients' clinical condition. Subsequent clinical follow up was obtained to establish the accuracy of the scintigram interpretation. Comparison of pulmonary uptake with that over the cardiac area is recommended as a simple and reliable method of confirming that the level of pulmonary activity is abnormal. In highly abnormal cases the cardiac area is seen as a 'negative heart' image due to the considerably increased activity in the lungs. This sign is best seen with abnormal diffuse uptake but is also seen with abnormal focal uptake. Care must be taken, as the sign may be masked, if uptake over the cardiac area itself is increased.

Severe spirometric defects in systemic lupus erythematosus. A possible role for bronchoalveolar lavage and gallium scanning

Two patients with systemic lupus erythematosus (SLE) developed progressive chronic pulmonary disease. Pulmonary bronchoalveolar lavage (BAL) and Gallium-67 scanning were performed and were consistent with alveolitis. In one patient, an open lung biopsy was performed and showed the presence of several immunoreactants as well as interstitial pneumonitis. Although mild pulmonary function abnormalities are common in SLE, some patients such as the two described in this report develop progressive and incapacitating pulmonary impairment. The need for developing standardized indices of pulmonary inflammation such as BAL and gallium scanning for the purposes of diagnosis, prognostication, and monitoring treatment responses in systemic lupus erythematosus is stressed.

Quantitative gallium 67 lung scan to assess the inflammatory activity in the pneumoconioses

Gallium 67 lung scan has recently become increasingly used to evaluate the biological activity of alveolitis of interstitial lung diseases and to stage the disease process. In order to have a more precise and objective indicator of the inflammatory activity in the lung, we and others have developed computer-based quantitative techniques to process the 67Ga scan. In this report, we compare the results of three such computer-based methods of analysis of the scans of 38 normal humans and 60 patients suspected to have pneumoconiosis. Results of previous investigations on the mechanisms of 67Ga uptake in interstitial lung disease are reviewed. These data strengthen the view that quantitative 67Ga lung scan has become a standard technique to assess inflammatory activity in the interstitial lung diseases and that computer-based method of analysis of the scan provides an index of inflammatory activity of the lung disease that correlates with lung lavage and biopsy indices of inflammation in the lung tissue.

Gallium-67 activity in bronchoalveolar lavage fluid in sarcoidosis

Roentgenograms and gallium-67 scans and gallium-67 counts of BAL fluid samples, together with differential cell counts, have proved to be useful in assessing activity and lung involvement in sarcoidosis. In active pulmonary sarcoidosis gallium-67 scans are usually positive. Quantitation of gallium-67 uptake in lung scans, however, may be difficult. Because gallium-67 uptake and cell counts in BAL fluid may be correlated, we set out to investigate gallium-67 activity in BAL fluid recovered from patient of different groups. Sixteen patients with recently diagnosed and untreated sarcoidosis, nine patients with healthy lungs, and five patients with CFA were studied. Gallium-67 uptake of the lung, gallium-67 activity in the lavage fluid, SACE and LACE levels, and alpha 1-AT activity were measured. Significantly more gallium-67 activity was found in BAL fluid from sarcoidosis patients than in that from CFA patients (alpha = .001) or patients with healthy lungs (alpha = .001). Gallium-67 activity in BAL fluid could be well correlated with the number of lymphocytes in BAL fluid, but poorly with the number of macrophages. Subjects with increased levels of SACE or serum alpha 1-AT showed higher lavage gallium-67 activity than did normals, but no correlation could be established. High gallium-67 activity in lavage fluid may be correlated with acute sarcoidosis or physiological deterioration; low activity denotes change for the better. The results show that gallium-67 counts in BAL fluid reflects the intensity of gallium-67 uptake and thus of activity of pulmonary sarcoidosis.

Reassessing the standard chest radiograph for intraparenchymal activity

The results concerning the activity or inactivity of the alveolitis determined with our proposed scoring system were comparable to those determined with gallium scanning in 68.2% of the patients with biopsy-proven sarcoidosis in our study. Certainly, further evaluation of a larger series of patients over a longer period of time will be required to more adequately evaluate this classification method. We also believe this methodology is reproducible and can be utilized by experienced interpreters of chest radiographs. If we closely reevaluate the 32% of the cases in which the radiographic results disagreed with the gallium assessment of activity, two points worthy of mention become evident. In one group the gallium indices were borderline for activity whereas in the other group the radiographic criteria were most likely indicative of irreversible parenchymal changes. When the radiographs for the latter group were reevaluated for signs of fibrosis such as volume loss, cystic changes, and alteration in vascular patterns, it was possible to delineate a significant false-positive group of patients. We will be reporting the long-term results of our observations over the next several years as well as adding more groups of patients to our initial study analysis. At that time, correlation with all other measurable parameters in determining high-intensity alveolitis versus low-intensity alveolitis will be compared to these new chest radiographic profiles.