Rationale: We report a new method to diagnose acute pulmonary embolism (PE) by single photon emission computerized tomography (SPECT) after administration of 99mTc-labeled anti-D-dimer (DI-80B3) monoclonal antibody Fab′ fragments. This novel technique provides an additional approach to diagnosing PE in patients for whom other methods are nondiagnostic or contraindicated. Objectives:We performed a prospective, multicenter study to investigate the sensitivity and specificity of 99mTc-DI-80B3/SPECT in patients with suspected acute PE. Methods: Subjects with a moderate to high clinical probability of PE or a positive D-dimer test underwent a PE-protocol contrastenhanced multidetector thoracic computed tomography (CT) scan as well as 99mTc-DI-80B3/SPECT (0.5 mg 99mTc-DI-80B3 intravenously followed by a thoracic SPECT 2.5 h later). Separate and independent adjudication committees, blinded to clinical data and other test results, interpreted the 99mTc-DI-80B3/SPECT scans (PE detected as foci of abnormally increased 99mTc uptake) and the thoracic CT scans using Prospective Investigation of Pulmonary Embolism Diagnosis II criteria. Measurements and Main Results:Of the 52 patients who were enrolled and completed both tests, 42 had both evaluable SPECT scans and thoracic CT scans. Using the criterion standard (thoracic CT scan) there were 21 patients with PE and 21 without. 99mTc-DI-80B3/ SPECT had a sensitivity of 76.2% (95% confidence interval, 52.8-91.8%) and a specificity of 90.5% (95% confidence interval, 69.8-98.8%). Treatment-related serious adverse events did not occur. Conclusions: 99mTc-DI-80B3/SPECT was sensitive and specific for acute PE in subjects with moderate to high clinical probability of PE or a positive D-dimer test. 99mTc-DI-80B3/SPECT demonstrated an acceptable safety profile and avoids exposure to contrast. Clinical trial NCT00519506 registered with www.clinicaltrials.gov.
|Number of pages||7|
|Journal||American journal of respiratory and critical care medicine|
|State||Published - Sep 15 2011|
- Pulmonary embolism
- Sensitivity and specificity
- Single photon emission computerized tomography