Purpose: Knowledge of pulmonary interlobar fissure integrity is of interest in a number of clinical and investigational applications. The authors developed and tested a high resolution CT based automated computerized scheme for this purpose. Methods: The fissure integrity assessment scheme consists of the following steps: ͑1͒ Fissure detection, ͑2͒ individual fissure identification, ͑3͒ fissure type determination, ͑4͒ "complete" interlobe surface estimation, and ͑5͒ fissure integrity estimation. For evaluation purposes, 50 anonymized chest CT examinations were ascertained and the complete and "incomplete" regions of the fissures of interest were manually marked by two experienced radiologists. After applying the scheme to the same examinations, differences among fissure percent completeness estimates based on the radiologists' manual markings and the automated computerized scheme were computed and compared. Results: Average differences in estimated fissure percent completeness ͑integrity͒ between the results of the computerized scheme and that based on each of the two radiologists' markings were 6.88% Ϯ 5.86%, 9.57% Ϯ 7.77%, and 4.19% Ϯ 5.64% for the right major fissures, the right minor fissures, and the left major fissures, respectively. The differences between results based on radiologists' markings for the same fissures were 4.27% Ϯ 3.32%, 7.02% Ϯ 5.54%, and 4.23% Ϯ 4.93%, respectively. The difference among the three matched measurement sets for each fissure were statistically significant ͑Friedman's test, p Յ 0.005͒ but paired comparisons showed that much of the observed difference was related to inter-reader differences rather than reader-computerized scheme differences. Computerized estimates were correlated with each of the radiologist's estimates ͑Spear-man, p Ͻ 0.0001͒. Conclusions: While variability between readers-based estimates of fissure integrity was smaller than differences between the computerized scheme and each of the readers, the result reported here are quite encouraging in that the magnitude of these differences were in the same magnitude, demonstrating the feasibility of using a computerized scheme for this purpose.

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The power Doppler color map reflects anticipated changes in renal perfusion after alterations in blood flow by vasoactive drugs.

The goal of this study was to assess whether radiologists' search paths for lung nodule detection in chest computed tomography (CT) between different rendering and display schemes have reliable properties that can be exploited as an indicator of ergonomic efficiency for the purpose of comparing different display paradigms. Eight radiologists retrospectively viewed 30 lung cancer screening CT exams, containing a total of 91 nodules, in each of three display modes [i.e., slice-by-slice, orthogonal maximum intensity projection (MIP) and stereoscopic] for the purpose of detecting and classifying lung nodules. Radiologists' search patterns in the axial direction were recorded and analyzed along with the location, size, and shape for each detected feature, and the likelihood that the feature is an actual nodule. Nodule detection performance was analyzed by employing free-response receiver operating characteristic methods. Search paths were clearly different between sliceby-slice displays and volumetric displays but, aside from training and novelty effects, not between MIP and stereographic displays. Novelty and training effects were associated with the stereographic display mode, as evidenced by differences between the beginning and end of the study. The stereo display provided higher detection and classification performance with less interpretation time compared to other display modes tested in the study; however, the differences were not statistically significant. Our preliminary results indicate a potential role for the use of radiologists' search paths in evaluating the relative ergonomic efficiencies of different display paradigms, but systematic training and practice is necessary to eliminate training curve and novelty effects before search strategies can be meaningfully compared.