title: [On the assessment of the diagnostic accuracy of imaging diagnosis by ROC and BVC analyses--in reference to X-ray CT and ultrasound examination of liver disease].
abstract: To achieve an effective assessment of diagnostic accuracies of currently used imaging methods on liver diseases, X-ray CT (CT) and realtime ultrasound (US), ROC analysis and a new analysis method, "the bias to variance characteristics (BVC)" were applied in parallel. The survey has been carried out to assess an image interpretation accuracy on cases with established diagnosis collected on the multi-institutional basis. The images, CT and US of liver diseases including localized and diffuse lesions were selected for image reading sessions and the interpretative difficulties were geared to an appropriate grade so that it does fit to the basic requirement of ROC analysis. Consequently, 91 cases were selected from a total of 258 cases which were collected from 16 institutions. Two image reading sessions were scheduled and a total of 28 radiologists and sonologists undertook the first session. The final analysis covered 8 radiologists for CT and 9 sonologists who carried out both sessions. The image interpretation results were fed to the computer and analyses were made accordingly. Analysis of the first image reading session gave true positive ratios (TPR) of CT and US as 92.5% and 97.4%, and true negative ratios (TNR) of 50.5% and 46.8%, respectively. The second reading session, in which both CT and US images were interpreted simultaneously, gave the similar values of TPRs, 96-97% and TNRs, 44-47%. The ROC analysis of existence of liver mass and diagnosis of malignancy resulted in the higher values in US compared to CT in the first separate reading, however, the 2nd session gave almost identical values in each modality. The diagnostic accuracy for the benign tumors, mostly consisted of hemangioma, CT reading gave higher accuracy rates compared to the US. The entirely new interpretations scheme, arbitrarily named as BVC was carried ou on matrix data obtained in the same experiment. The scatterograms plotted according to the BV values, the mean and the standard deviation inherent to individual cases have demonstrated marked variations among individual cases most likely reflecting the interpretative difficulty of respective images, thus indicating the method to be well in adjunct to the ROC analysis.
authors.forename: K
authors.initials: K
authors.lastname: Fukuhisa
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: T A
authors.initials: TA
authors.lastname: Iinuma
authors.forename: Y
authors.initials: Y
authors.lastname: Tateno
authors.forename: N
authors.initials: N
authors.lastname: Moriyama
authors.forename: C
authors.initials: C
authors.lastname: Kido
authors.forename: M
authors.initials: M
authors.lastname: Fukuda
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D005260:Female; D006801:Humans; D007564:Japan; D008107:Liver Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D012372:ROC Curve; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography