Acute rejection following lung transplantation: limitations in accuracy of thin-section CT for diagnosis.

PURPOSE: To evaluate the sensitivity, specificity, predictive values, and accuracy of thin-section computed tomography (CT) for the diagnosis of acute rejection following lung transplantation and to determine whether any individual CT abnormalities are associated with histopathologically proved acute rejection. MATERIALS AND METHODS: Thin-section CT studies from 64 lung transplant recipients were retrospectively reviewed. CT studies were temporally correlated with various grades of biopsy-proved acute rejection (n = 34); 30 other CT studies were from a control group with no histopathologic evidence of acute rejection. Acute rejection was diagnosed as present or absent, and the diagnostic was calculated. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT for the diagnosis of acute rejection were as follows: 35%, 73%, 60%, 50%, 53%, respectively. No individual CT finding was significantly associated with acute rejection. The sensitivity of CT for the detection of various grades of acute rejection was 17% for grade A1, 50% for grade A2, and 20% for grade A3. The combination of volume loss and septal thickening, with or without pleural effusion, was never seen in the absence of acute rejection. CONCLUSION: Thin-section CT has limited accuracy for the diagnosis of acute rejection following lung transplantation, and no individual CT finding is significantly associated with this diagnosis.

Multidetector-row spiral computed tomography in the diagnosis of thoracic diseases.

Since its introduction in 1992, spiral computed tomography (CT) scanners constructed with a single row of detectors have revolutionized imaging of thoracic diseases. Current state-of-the-art models use up to 16 detectors and are capable of acquiring 4 contiguous slices of data with each gantry rotation; systems with 8 data acquisition units (and more) are currently in development. The principal advantages offered by these systems are increased scanning speed and the ability to obtain volumetric data in high resolution. These features enable imaging with enhanced contrast concentration, decreased contrast load, decreased respiratory and cardiac motion artifact, and multiplanar and 3-dimensional reconstruction capabilities. Herein we first review the technical aspects of multidetector spiral CT scanning. The arrangement and various combinations of the detector rows are discussed. Key scanning variables, including collimation (slice thickness), pitch (the rate of table travel per gantry rotation divided by the beam collimation), and gantry speed, are briefly addressed in the context of their interrelationships. Comparison is made with single-detector-row systems to emphasize the superior scanning speed and resolution. We then discuss the various clinical applications of multidetector spiral CT, including CT pulmonary angiography, CT aortography, virtual bronchoscopy, and multiplanar and 3-dimensional reconstructions.