Incremental value of color coding in 3D volume rendered CT images for interpretation of complex cardiothoracic vascular malformations.

Objectives: To evaluate the benefit of color coding of CT angiography images for the assessment of complex cardiovascular malformations by comparing the quality of 3D (dimensional) volume rendered (VR) images before and after vessel color coding.

Methods: Cardiothoracic CT images of 34 patients with complex vascular malformations were retrospectively selected for post processing. 3D VR images were created without and after color coding of the target vessels. Source images as well as selected 3D VR images without and with color coding were reviewed independently by 4 observers and scores were recorded on a 4-point scale for overall image quality, visualization conspicuity of target vessels, and final interpretation of target structures.

Results: Overall diagnostic advantages of color coded VR images compared with non-color coded VR images included; improved visualization of the anatomical course of vessels, improved visualization of the extent of abnormality, better understanding of the spatial relationship of structures (i.e. to right ventricle outflow tract), and improved overall quality of the images. For all comparisons the color coded score was statistically significantly better than the non-color coded score (p<0.0001). A trend showed that review speed was faster for color coded images (p=0.06). Good inter-observer agreement was achieved for the target conspicuity and final interpretation scores with weighted Kappa score of 0.66 (95% CI: 0.54, 0.79) and 0.71 (95% CI: 0.60, 0.81) respectively.

Conclusion: Color coded 3D VR images can optimize visualization of vascular structures and improve interpretation of complex vascular malformation in cardiothoracic CT studies.