THORACIC AORTIC DISEASE - EVALUATION USING A SINGLE MRA VOLUME SERIES

Objective: Use of MRA for thoracic aortic disease (TAD) evaluation has been limited. This report describes an initial experience with TAD ev aluation using a single MRA volume series. Materials and Methods: A si ngle volume series, based on sequential 2D TOF MRA, was acquired in 30 cases (28 with suspected TAD and 2 normals). Each series was processe d using multiplanar reconstruction (MPR) and maximum intensity project ion (MIP); resulting tomographic (one base and two MPR) and MIP sets w ere blindly interpreted by four reviewers to detect TAD and, if presen t, to diagnose its specific form. For cases incorrectly interpreted, t he standard MR images were subsequently interpreted. Results: The TAD categories included aneurysm (n = 13), dissection (n = 9), and arch an omalies (n = 5). Sensitivities were high for TAD overall (89-100%) and TAD in ascending and descending portions; sensitivities were lower fo r TAD of the arch (two of four reviewers greater than or equal to 90% for TAD overall and descending TAD). Specificities for TAD overall had a wider range (67-100%), but were high for ascending, arch, and desce nding portions (three to four of four reviewers greater than or equal to 90% for each). Sensitivities for aneurysms (69-92%) and dissections overall (67-100%) were comparable, as they were in ascending and arch portions; descending dissection was better detected than descending a neurysm (two of four reviewers greater than or equal to 90% for ascend ing or arch aneurysm and for descending dissection); overall specifici ties (88-100 vs. 81-95%) and specificities in ascending, arch, and des cending portions were also comparable (three to four of four reviewers greater than or equal to 90% for both in each portion; two of four re viewers greater than or equal to 90% for dissection overall). Each rev iewer achieved greater than or equal to 70% diagnostic accuracy for TA D (one of four reviewers = 85%); accuracies for each category were com parable. Interpretation of standard MR images corrected all detection and most diagnostic (greater than or equal to 63% errors.Conclusion: T his initial experience with conventional TOF MRA for TAD evaluation is encouraging, but it indicates the potential for advancements in data acquisition and/or postprocessing.