Table 1.
Imaging parameters for T2WI, EPI-DWI, and TSE-DWI.
Table 2.
Criteria of pathology and MRI images for T-staging of rectal cancer.
Fig 1.
Stage T1 rectal carcinoma in a 75-year-old woman.
From the T2WI image (A) alone, all readers misdiagnosed the stage. On the TSE-DWI image (B), an area of high signal intensity with a low signal intensity of stalk was depicted and diagnosed as stage T1. However, this finding was not presented on the EPI-DWI image (C) due to distortion artifacts, and all readers misdiagnosed the stage, as with the T2WI image alone.
Fig 2.
Stage T3 rectal carcinoma in a 69-year-old woman.
On the T2WI image (A) alone, intermediate intensity of tumor was shown beyond the muscularis propria (arrow). Higher image noise was seen on the TSE-DWI image (B) than on the EPI-DWI image (D), but this did not degrade the fusion image of TSE-DWI (C). On the fusion image of TSE-DWI (C), a colored area of diffusion restriction corresponded to the low intensity area on the T2WI-presenting tumor (arrow). On the fusion image of EPI-DWI (E), a colored area of diffusion restriction was depicted beyond the low intensity area on T2WI (arrow) due to distortion artifacts, but did not degrade the T-staging.
Fig 3.
Stage T2 rectal carcinoma in a 75-year-old woman.
On the T2WI image (A), a low intensity area extended from the mesorectal fascia into the surface of the uterus (arrow-head). Five readers misdiagnosed the stage as T4a or T4b with T2WI alone. This area did not show high intensity on the DWI image, and was considered as fibrosis. A high intensity lesion was seen on TSE-DWI (B) and EPI-DWI (D) image (arrow). On the fusion image of TSE-DWI (C), 7 readers accurately diagnosed the stage as T2. On the fusion image of EPI-DWI (E), an area of diffusion restriction was shown beyond the muscularis propria (arrow) probably due to image distortion, and the stage was misdiagnosed as T3.
Table 3.
Inter-observer agreement of T-staging in all 20 cases and agreement between respective reader’s diagnosis and pathology in 7 cases for three image sequences.
Table 4.
Comparison of visual T-staging diagnostic confidence scores and distribution of median scores for three image sequences assigned by 10 readers.
Table 5.
T-stages diagnosed by 10 readers in descending order of frequency for 7 pathologically-proven T-stages.
Table 6.
Assessment of visual image quality of EPI-DWI and TSE-DWI by 10 readers and distribution of median scores.