67Ga citrate imaging in AIDS-related Pneumocystis carinii pneumonia in Japan

Six AIDS patients with Pneumocystis carinii pneumonia (PCP) underwent 67Ga scan as part of their evaluation. Only one patient of them showed the characteristic 67Ga distribution pattern for PCP, that is, diffuse, increased, bilateral lung activity greater than liver activity. Two patients who were receiving therapy for PCP and one patient with recurrent PCP showed focal or uneven 67Ga lung uptake. In the four patients, the scan showed more extensive lesion than the chest radiograph. The other two patients who died 2 months later of cellular immunodeficiency showed no or very slight lung uptake of 67Ga. In summary, 67Ga scanning is useful diagnostic procedure in evaluation of PCP in patients with AIDS.     

Occult Candida thyroid abscess diagnosed by gallium-67 scanning

A clinically silent fungal thyroid abscess was identified by Ga-67 citrate scanning and successfully drained surgically in a young leukemic patient. Whole-body radionuclide scanning remains a valuable method to help diagnose persistent fever in the immunocompromised host.     

Pneumocystis carinii pneumonia (pneumocystosis)

In former times Pneumocystis carinii (PC) primarily affected premature infants. More recently, it has proved to be one of the major infectious complications among immunocompromised patients, particularly those with AIDS. The most frequent radiographic feature is diffuse, bilateral alveolar and interstitial perihilar shadowing, spreading in a butterfly pattern. The typical findings may mimic other infectious diseases, but the presence of large pleural effusions of hilar adenopathy is evidence against the diagnosis of PC-pneumonia.     

FDG-PET imaging in Pneumocystis carinii pneumonia

The authors present a case of a 26-year-old man, under investigation for Cushing syndrome, who presented acutely with a dry cough and fever. The blood tests were unremarkable apart from a moderate to severe leukopenia. Imaging tests were suggestive of an atypical pneumonia, which was proven to be Pneumocystis carinii pneumonia (PCP) on cytology examination of a bronchoalveolar lavage (BAL). The acute lung changes were demonstrated on a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) study. After treatment, a follow-up study showed complete resolution of these changes. The authors suggest that FDG PET may have a role to play in the diagnosis and, in particular, the monitoring of PCP in immunocompromised patients.     

Accuracy of high-resolution CT in distinguishing between Pneumocystis carinii pneumonia and non- Pneumocystis carinii pneumonia in AIDS patients

The aim of this study was to assess the value of high-resolution CT in distinguishing between Pneumocystis carinii and non-Pneumocystis carinii pneumonia (PCP) in patients HIV-positive and high risk to have PCP. We performed a prospective study in 30 patients with <200 CD4 lymphocytes, clinical symptoms of pulmonary disease and chest X-ray non-conclusive for pulmonary infection. Evaluated CT findings included ground-glass opacities, reticulation, tree-in-bud appearance, consolidation, cystic lesions, bronchiectasis and lymphadenopathies. The diagnosis of "examination suggestive of PCP" was applied to cases showing a diffuse or predominant ground-glass pattern in the upper fields, associated or not with reticulations and small cystic lesions. The sensitivity, specificity, positive predictive value and negative predictive value of high-resolution computed tomography (HRCT) for the diagnosis of PCP was 100, 83.3, 90.5 and 100%, respectively. Pneumocystis carinii pneumonia was not demonstrated in any of the cases classified as "examination not suggestive of PCP". Significant small airway disease was not observed in any of the PCP cases. We conclude that HRCT is a reliable method for differentiating PCP from other infectious processes in HIV-positive patients and a good method to rule our PCP. Its inclusion in the diagnostic algorithm of lung infections is justified in these patients. Electronic Publication     

Pulmonary disposition of gallium-67 in patients with Pneumocystis pneumonia: an analysis using bronchoalveolar lavage.

Gallium-67 localizes to the cellular fraction of bronchoalveolar lavage (BAL) fluid in patients with sarcoidosis, idiopathic pulmonary fibrosis, as well as normal subjects. To further study 67Ga disposition in BAL fluid, 11 patients with Pneumocystis carinii pneumonia (PCP) and 8 patients with a variety of other lung diseases, underwent BAL 24 hr after 67Ga injection. Compared to the non-PCP patients, PCP patients had high uptake gallium scans at 24 and 72 hr, and showed significantly increased radioactivity in both unfractionated lavage and in the acellular, supernatant fraction of BAL. The mean ratio of total supernatant/cell pellet radioactivity was also higher in patients with PCP (1.23 +/- 0.27 versus 0.24 +/- 0.05, p less than 0.01). Supernatant radioactivity correlated with the presence of neutrophil alveolitis, but not with BAL transferrin concentrations. We conclude that neutrophil alveolitis in PCP promotes 67Ga accumulation in the acellular fraction of BAL fluid. However, the high uptake 67Ga scans observed in PCP patients without neutrophil alveolitis suggest that the mechanism of pulmonary uptake of 67Ga is not fully elucidated by BAL fluid analysis alone.     

Pneumocystis carinii pneumonia: CT and HRCT observations

We examined the chest radiography, CT, and high resolution CT (HRCT) of 14 patients with proven Pneumocystis carinii pneumonia. We compared the radiographic and HRCT patterns of abnormal lung parenchyma with histologic sections obtained in those 11 patients who had had transbronchial lung biopsies. Diffuse bilateral perihilar airspace disease was the most common radiographic pattern. Both CT and HRCT showed "ground glass" opacity in the lungs, through which the vessels remained visible in all patients. No enlarged lymph nodes or pleural effusions were seen in patients without associated lymphoproliferative disorders.     

Thyroid scanning with gallium-67 and cesium-131.

The roles of 131Cs and 67Ga in the evaluation of solitary thyroid nodules were investigated. Radionuclide scans were performed with 67Ga and 131I in 27 patients and with 131Cs and 131I in 43 patients. Gallium-67 detected only two of eight malignant nonfunctioning nodules and 131Cs detected one of three such nodules. The contribution of 131Cs and 67Ga to the preoperative identification of malignant thyroid lesions is of doubtful value.     

The usefulness of gallium-67 citrate scanning in testicular seminoma

An analysis of 77 consecutive patients with a histologic diagnosis of seminoma testis, assessed and treated at the Cross Cancer Institute between 1977 and 1982, is presented. Ga-67 citrate was first used in the assessment of patients with malignant testicular tumors in 1973. Following three years of study that supported the observation of the gallium-avid nature of seminoma, gallium scans became routine in the initial staging assessment and were used also when recurrence was suspected. From 1977 through 1982, 72 patients with biopsy-proven seminoma testis were assessed initially for extent of disease by Ga-67 scanning. Comparison with intravenous pyelography and bipedal lymphography was possible for accuracy of tumor assessment. The scan sensitivity was 83%, and the specificity was 95%. During the same period, gallium was studied in nonseminomatous testicular tumors but the results were disappointing and its use was discontinued. The gallium-avid nature of seminoma testis may be useful in determining the extent of disease.