Chun K. Kim

Diagnosis of Musculoskeletal Infection Using Combined In-111 Labeled Leukocyte and Tc-99m Sc Marrow Imaging

Seventy-three patients with various underlying disorders that could potentially alter distribution of bone marrow underwent in-111 labeled autologous leukocyte and Tc-99m SC marrow imaging to exclude musculoskeletal Infection. There were 22 cases of infection among the 73 patients studied. When interpreted in isolation, labeled leukocyte images were considered positive for infection when uptake of labeled cells in the region of interest exceeded uptake in the corresponding contralateral side. The sensitivity, specificity, and accuracy of the study using this criterion were 86%, 12%, and 34%, respectively. When interpreted in conjunction with sulfur colloid marrow images, studies were considered positive for infection when uptake in the region of interest on leukocyte and marrow images was spatially incongruent The sensitivity, specificity, and accuracy of this dual tracer modality were 100%, 94%, and 96%, respectively. Three patients with infection and abnormal leukocyte/marrow images underwent repeat imaging after appropriate therapy. Images were interpreted as normal in two of them; both were infection free at subsequent surgery. Images of the third patient were interpreted as consistent with persistent infection, and operative cultures grew out Staphylococcus aureus. In summary, combined leukocyte/marrow imaging is a highly accurate method for diagnosing musculoskeletal infection and overcomes certain inherent limitations of labeled leukocyte imaging alone.

Role of in-111 labeled leukocyte scintigraphy in the diagnosis of intracerebral lesions.

The differential diagnosis of intracerebral enhancing lesions on contrast computed tomography includes tumors, abscesses, and cerebrovascular accidents. Particularly important is the differentiation between tumor and abscess. While ln-111 labeled leukocyte imaging is an accurate test for identification of foci of infection in general, the role of this procedure in the evaluation of the intracranial lesion is not well established. We undertook a retrospective review of 16 patients with contrast enhancing intracerebral lesions identified on computed tomography, who were also studied with labeled leukocyte imaging. Final diagnoses were: abscess (n=2), primary brain tumor (n=6), metastasis (n=4), dermoid cyst (n=1), and cerebral infarct (n=3). There were two positive labeled leukocyte studies; both were cerebral abscesses. No labeled leukocyte activity was identified in any of the tumors or infarcts. We conclude that ln-111 labeled leukocyte imaging is an accurate method of differentiating infectious from noninfectious causes of intracerebral lesions identified on computed tomography.

Bone Scintigraphy in Pleural Metastases of Osteogenic Sarcoma

A 27-year-old woman with metastatic osteogenic sarcoma of the pleura and lungs underwent Tc-99m MDP bone scintigraphy as part of a metastatic evaluation. Extensive, intense, pleural, and pulmonary parenchymal tracer uptake in the metastatic deposits was identified.

Torsion of a testicular appendage in an adult male.

Torsion of a testicular appendage is a self-limited process: with rest and analgesics, it resolves within one week. Clinically, the patient presents with a gradual onset of mild to moderate scrotal pain localized to the upper pole of the testis. Urinary symptoms are absent. The infarcted appendage may be seen through the thin scrotal skin; this “blue dot” sign is pathognomonic of the entity. It is not always possible, on clinical grounds alone, to distinguish torsion of an appendage from torsion of a testis; under these circumstances, radionuclide scrotal scintigraphy is a paramount diagnostic modality, rapidly and accurately separating those individuals who require surgical intervention from those in whom more conservative therapy will suffice. The radionuclide presentation of torsion of a testicular appendage is most often that of a normal scan, although mildly increased perfusion as well as photopenic defects have been reported. The case presented is unusual because of the patients age (25 years old) and the striking scan appearance.

Effect of patient position on interpretation of lung images complicated by chest radiograph opacities

Lung images in which perfusion defects correspond to chest radiograph (CXR) opacities in size and location are generally classified as having an intermediate probability for pulmonary embolism, while those studies in which the perfusion defects are considerably smaller than the CXR opacities are classified as having a low probability for pulmonary embolism. A case is presented in which, by imaging a patient in both the erect and supine positions, the authors were able to change the interpretation of the study from intermediate probability (perfusion defect = CXR opacity) to low probability (perfusion defect < CXR opacity).

Osteopetrosis: nuclear medicine pathophysiologic correlation

The authors present the case of a 28-year-old woman with osteopetrosis who underwent multiple nuclear medicine procedures, making it possible for the nuclear medicine pathophysiologic correlales in this unusual disease to be studied.

Serial dacryoscintigraphy before and after treatment with pseudoephedrine

Radionuclide dacryoscintigraphy is an accurate physiologic method for evaluating the nasolacrimal drainage apparatus. The following case report illustrates the role of this procedure in the initial workup of epiphora, as well as its value in assessing response to therapy with pseudoephedrine.

In-111 leukocyte imaging in disseminated mycobacterium avium-intracellulare infection.

Radionuclide procedures such as In-111 labeled leukocyte and Ga-67 citrate scintigraphy are valuable diagnostic tools in the evaluation of patients with AIDS. The authors describe a strikingly abnormal labeled leukocyte study in a man with AIDS and disseminated Mycobacterium avium-intracellulare infection.

In-111 labeled leukocyte imaging in intrathoracic colitis.

In-111 labeled leukocyte scintigraphy correctly identified a segment of intrathoracic colon as the source of infection in a 69-year-old woman with a history of colonic interposition for esophageal perforation.

In-111 labeled leukocyte scintigraphy in a case of multifocal candidiasis

The value of indium-111 labeled leukocyte scintigraphy for the diagnosis of infection in the general population is well documented; there is less information available on its role in the evaluation of the immunocompromised patient. In this study, leukocyte scintigraphy was performed on a 31-year-old immunocompromised woman who had a possible intra-abdominal abscess. No abscess was detected, but intense oral, esophageal, gastric, and vaginal uptake was observed. Candida infection was histologically confirmed at all four sites.