Comparison of manual and semi-automatic measuring techniques in MSCT scans of patients with lymphoma: a multicentre study.

OBJECTIVES: Multicentre evaluation of the precision of semi-automatic 2D/3D measurements in comparison to manual, linear measurements of lymph nodes regarding their inter-observer variability in multi-slice CT (MSCT) of patients with lymphoma. METHODS: MSCT data of 63 patients were interpreted before and after chemotherapy by one/two radiologists in five university hospitals. In 307 lymph nodes, short (SAD)/long (LAD) axis diameter and WHO area were determined manually and semi-automatically. Volume was solely calculated semi-automatically. To determine the precision of the individual parameters, a mean was calculated for every lymph node/parameter. Deviation of the measured parameters from this mean was evaluated separately. Statistical analysis entailed intraclass correlation coefficients (ICC) and Kruskal-Wallis tests. RESULTS: Median relative deviations of semi-automatic parameters were smaller than deviations of manually assessed parameters, e.g. semi-automatic SAD 5.3 vs. manual 6.5 %. Median variations among different study sites were smaller if the measurement was conducted semi-automatically, e. g. manual LAD 5.7/4.2 % vs. semi-automatic 3.4/3.4 %. Semi-automatic volumetry was superior to the other parameters (2.8 %). CONCLUSIONS: Semi-automatic determination of different lymph node parameters is (compared to manually assessed parameters) associated with a slightly greater precision and a marginally lower inter-observer variability. These results are with regard to the increasing mobility of patients among different medical centres and in relation to the quality management of multicentre trials of importance. KEY POINTS: • In a multicentre setting, semi-automatic measurements are more accurate than manual assessments. • Lymph node volumetry outperforms all other semi-automatically and manually performed measurements. • Use of semi-automatic lymph node analyses can reduce the inter-observer variability.

Therapy response evaluation of malignant lymphoma in a multicenter study: comparison of manual and semiautomatic measurements in CT.

PURPOSE: Comparison of manual one-/bi-dimensional measurements versus semi-automatically derived one-/bi-dimensional and volumetric measurements for therapy response evaluation of malignant lymphoma during CT follow-up examinations in a multicenter setting. MATERIALS AND METHODS: MSCT data sets of patients with malignant lymphoma were evaluated before (baseline) and after two cycles of chemotherapy (follow-up) at radiological centers of five university hospitals. The long axis diameter (LAD), the short axis diameter (SAD) and the bi-dimensional WHO of 307 target lymph nodes were measured manually and semi-automatically using dedicated software. Lymph node volumetry was performed semi-automatically only. The therapeutic response was evaluated according to lymphoma-adapted RECIST. RESULTS: Based on a single lymph node, semi-automatically derived multidimensional parameters allowed for significantly more accurate therapy response classification than the manual or the semi-automatic unidimensional parameters. Incorrect classifications were reduced by up to 9.6%. Compared to the manual approach, the influence of the study center on correct therapy classification is significantly less relevant when using semi-automatic measurements. CONCLUSION: Semi-automatic volumetry and bi-dimensional WHO significantly reduce the number of incorrectly classified lymphoma patients by approximately 9.6% in the multicenter setting in comparison to linear parameters. Semi-automatic quantitative software tools may help to significantly reduce wrong classifications that are associated with the manual assessment approach. KEY POINTS: ► Semi-automatic volumetry and bi-dimensional WHO significantly reduce the number of incorrectly classified lymphoma patients ► Manual lymph node evaluation with uni-dimensional parameters is inferior to semi-automatic analysis in a multicenter setting ► Semi-automatic quantitative software tools should be introduced in clinical study evaluation.

MSCT follow-up in malignant lymphoma: comparison of manual linear measurements with semi-automated lymph node analysis for therapy response classification.

PURPOSE: Assignment of semi-automated lymph node analysis compared to manual measurements for therapy response classification of malignant lymphoma in MSCT. MATERIALS AND METHODS: MSCT scans of 63 malignant lymphoma patients before and after 2 cycles of chemotherapy (307 target lymph nodes) were evaluated. The long axis diameter (LAD), short axis diameter (SAD) and bi-dimensional WHO were determined manually and semi-automatically. The time for manual and semi-automatic segmentation was evaluated. The ref. standard response was defined as the mean relative change across all manual and semi-automatic measurements (mean manual/semi-automatic LAD, SAD, semi-automatic volume). Statistical analysis encompassed t-test and McNemar's test for clustered data. RESULTS: Response classification per lymph node revealed semi-automated volumetry and bi-dimensional WHO to be significantly more accurate than manual linear metric measurements. Response classification per patient based on RECIST revealed more patients to be correctly classified by semi-automatic measurements, e. g. 96.0 %/92.9 % (WHO bi-dimensional/volume) compared to 85.7/84.1 % for manual LAD and SAD, respectively (mean reduction in misclassified patients of 9.95 %). Considering the use of correction tools, the time expenditure for lymph node segmentation (29.7 ± 17.4 sec) was the same as with the manual approach (29.1 ± 14.5 sec). CONCLUSION: Semi-automatically derived "lymph node volume" and "bi-dimensional WHO" significantly reduce the number of misclassified patients in the CT follow-up of malignant lymphoma by at least 10 %. However, lymph node volumetry does not outperform bi-dimensional WHO.