Clinical utility of bone scan features of pleural effusion: sensitivity and specificity for malignancy based on pleural fluid cytopathology.

UNLABELLED: Asymmetric chest activity with malignant and benign pleural effusions has been described in bone scans. However, the clinical utility of this finding is not elucible from the literature. We developed specific scintigraphic criteria for malignant pleural effusion and retrospectively assessed their sensitivity and specificity in a group of patient scans. METHODS: Pleural fluid was submitted for cytopathology from 850 patients over a 5-yr period. Bone scans were done within 2 mo of the thoracentesis in 74 patients. As a consensus panel, we reread the scans and reviewed the cytology. RESULTS: The effusions were cytologically malignant in 25/74 patients (34%), indeterminate in 9/74 (12%) and benign in 40/74 (54%). Based on cytopathology, malignant pleural effusions were detected by bone scans with a sensitivity of 34%-50% and a specificity of 78%-89%; true sensitivity and specificity was somewhere in between averaging 42% (95% confidence interval 24%-60%) and 84% (95% confidence interval 73%-95%), respectively. CONCLUSIONS: The bone scan is frequently the first examination suggesting pleural metastasis, and when it is detected it should be pursued beyond pleural fluid cytology, if negative or indeterminate.

Optimized diagnostic strategy for neuroblastoma in opsoclonus-myoclonus.

Infantile myoclonic encephalopathy (opsoclonus-myoclonus or IME) is a rare clinical syndrome associated with occult neuroblastoma in 20%-50% of all cases. IME is the initial presentation of neuroblastoma in 1%-3% of children. Imaging approaches including chest radiography and abdominal computed tomography (CT) have been proposed to detect neuroblastoma in IME. Metaiodobenzylguanidine (MIBG) is highly effective in the detection of neuroblastoma. These scans can identify both soft-tissue and skeletal lesions anywhere in the body. Our purpose was to attempt to determine the best screening method for detection of occult neuroblastoma in patients with IME. Records of all neuroblastoma patients from 1983 to May 1991 were reviewed. Four cases of IME with neuroblastoma were identified in which imaging studies included an MIBG scan. All four patients had positive MIBG scans (100%) while only two had masses on initial CT (50%). In the three patients initially evaluated by traditional methods, the mean time to diagnosis and the mean number of advanced radiologic studies were 7.5 mo and 7.3 studies respectively. The patient screened with MIBG had only cranial and abdominal CT prior to surgery. Although based on a limited number of patients, results suggest that MIBG may prove to be a useful screening procedure in patients with IME. Traditional imaging modalities can then be directed to evaluate sites of disease identified by MIBG scans.

Efficacy of metaiodobenzylguanidine as a scintigraphic agent for the detection of neuroblastoma.

RATIONALE AND OBJECTIVES: Metaiodobenzylguanidine (MIBG) has been shown to be both sensitive and highly specific for the detection of neuroblastoma. However, controversy surrounds its sensitivity in detecting neuroblastoma when compared with radionuclide (technetium 99m-methylene diphosphonate [99mTc]-MDP) bone scans. Because a diagnostic test ideally should be easy to interpret in addition to being sensitive and specific, this study aims to determine the most efficacious scintigraphic agent for diagnostic use in neuroblastoma. METHODS: Twenty patients with neuroblastoma had a total of 26 paired MIBG and 99mTc-MDP bone scans obtained less than 4 weeks apart. Each study was evaluated independently of its counterpart by six separate observers (3 experienced and 3 inexperienced in MIBG scintigraphy) to determine the presence or absence of disease and the tumor burden. RESULTS: Inexperienced observers reported more confidence in their interpretations of 99mTc-MDP bone scans; however, seven false-positive bone scans were reported. Using MIBG, all true-positive and true-negative scans, as well as significantly more sites of both primary and metastatic disease, were identified by all observers. CONCLUSION: This study suggests that MIBG is the more efficacious agent for the scintigraphic evaluation of neuroblastoma.

Clofazimine crystals in alveolar macrophages from a patient with the acquired immunodeficiency syndrome.

An induced sputum specimen from a 35-year-old patient with the acquired immunodeficiency syndrome (AIDS) contained numerous bright orange-red needle-shaped crystal inclusions in his alveolar macrophages. Careful questioning revealed that he recently had been treated for 7 months with clofazimine (200 mg/d) for persistent Mycobacterium avium complex bacteremia. The striking cytologic finding observed is diagnosed easily if the characteristic morphologic appearance of the crystals and their location within the cytoplasm of macrophages and cells of the reticuloendothelial system is appreciated. Although this is the first observation at San Francisco (Calif) General Hospital of clofazimine crystals in a respiratory specimen from a patient with AIDS, the potential of more widespread therapy with clofazimine in patients with AIDS who are infected with M avium complex makes it imperative that the microscopic appearance of these crystals be recognized.

Asymmetry of salivary gland I123 metaiodobenzylguanidine (MIBG) uptake in a patient with cervical neuroblastoma and Horner's syndrome--possible etiologic mechanisms.

Horner's syndrome may be due to a variety of serious underlying disorders including cervical neuroblastoma. Horner's syndrome results from a unilateral disruption of the sympathetic innervation to the head and neck. We report a patient with cervical neuroblastoma in whom post operative metaiodobenzylguanidine (MIBG) scans showed a striking decrease in uptake in the ipsilateral salivary glands. Since the bio-distribution of I123 metaiodobenzylguanidine in the salivary glands in also dependent on sympathetic innervation, the presence of Horner's syndrome can be reflected in the MIBG scan.

Unique scintigraphic findings of bile extravasation in the presence of ascites: a complication of hepatic transplantation.

A 99mTc-HIDA scan was performed on a 4-mo-old female, six days after hepatic transplantation. Gradually, a diffuse increase in activity was seen over the peritoneal region, consistent with a slow bile leak into ascitic fluid. Although the scintigraphic appearance of a bile leak has been previously described, it is usually seen as a focal area of extrabiliary activity. In this case, we report a pattern identified when the leak occurs in conjunction with ascites.

Duration of etidronate effect demonstrated by serial bone scintigraphy.

There have been several reports of etidronate disodium (EHDP) interference upon the biodistribution of 99mTc-methylene diphosphonate (MDP). With the increasing use of etidronate for the treatment of Paget's disease, hypercalcemia, and osteoporosis, nuclear physicians can expect to encounter increasing numbers of cases in which EHDP-induced artifacts impair the diagnostic utility of bone scans. The temporal duration of this effect is unknown yet obviously important. We report serial bone scintigraphy in a patient who received a single dose of EHDP for hypercalcemia. Normal biodistribution of 99mTc-MDP was noted at 15 days, suggesting that 2 wk are sufficient before performing a bone scan after a single intravenous dose of etidronate.