Korean J Radiol.  2019 Jul;20(7):1207-1215. 10.3348/kjr.2018.0824.

CT Evaluation for Clinical Lung Cancer Staging: Do Multiplanar Measurements Better Reflect Pathologic T-Stage than Axial Measurements?

• Park S
• Lee SM
• Choe J
• Lee JG
• Lee SM
• Do KH
• Seo JB

• KMID: 2467031
• DOI: http://doi.org/10.3348/kjr.2018.0824

Abstract

OBJECTIVE
To retrospectively investigate whether tumor size assessment on multiplanar reconstruction (MPR) CT images better reflects pathologic T-stage than evaluation on axial images and evaluate the additional value of measurement in three-dimensional (3D) space.
MATERIALS AND METHODS
From 1661 patients who had undergone surgical resection for primary lung cancer between June 2013 and November 2016, 210 patients (145 men; mean age, 64.4 years) were randomly selected and 30 were assigned to each pathologic T-stage. Two readers independently measured the maximal lesion diameters on MPR CT. The longest diameters on 3D were obtained using volume segmentation. T-stages determined on CT images were compared with pathologic T-stages (overall and subgroup"”Group 1, T1a/b; Group 2, T1c or higher), with differences in accuracy evaluated using McNemar's test. Agreement between readers was evaluated with intraclass correlation coefficients (ICC).
RESULTS
The diagnostic accuracy of MPR measurements for determining T-stage was significantly higher than that of axial measurement alone for both reader 1 (74.3% [156/210] vs. 63.8% [134/210]; p = 0.001) and reader 2 (68.1% [143/210] vs. 61.9% [130/210]; p = 0.049). In the subgroup analysis, diagnostic accuracy with MPR diameter was significantly higher than that with axial diameter in only Group 2 (p < 0.05). Inter-reader agreements for the ICCs on axial and MPR measurements were 0.98 and 0.98. The longest diameter on 3D images showed a significantly lower performance than MPR, with an accuracy of 54.8% (115/210) (p < 0.05).
CONCLUSION
Size measurement on MPR CT better reflected the pathological T-stage, specifically for T1c or higher stage lung cancer. Measurements in a 3D plane showed no added value.

Keyword

Lung; Neoplasm staging; Multidetector computed tomography

MeSH Terms

Humans
Lung Neoplasms*
Lung*
Male
Multidetector Computed Tomography
Neoplasm Staging
Retrospective Studies

Figure

• 

  Fig. 1 Flow chart of patient inclusion procedure.

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  Fig. 2 Bland-Altman plots showing relationship between CT and pathologic diameters.A–D. Graphs show differences between CT diameter and pathologic size. X-axes represent pathologic size and Y-axes represent differences in size between CT diameter and pathologic size. A. axial diameter measured by reader 1. B. MPR diameter measured by reader 1. C. axial diameter measured by reader 2. D. MPR diameter measured by reader 2. MPR = multiplanar reconstruction, SD = standard deviation

• 

  Fig. 3 Correct staging using MPR in T4 stages.(A) Axial, (B) coronal, and (C) sagittal CT scans of large lobulated mass in left lower lobe of 74-year-old man. Tumor lies anterosuperiorly to posteroinferiorly, so longest dimension of tumor was captured on sagittal plane. On axial CT alone, both readers underestimated tumor size (64 mm and 62 mm), with corresponding stage being T3. On sagittal CT, diameter measured by both readers was 74 mm, which was equal to pathologic diameter and resulted in accurate clinical staging as T4. D. Longest diameter on three-dimensional was 77 mm.

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