| Theme |
CT colonography |
| Title |
Detection and diagnosis of superficial depressed type early colorectal cancer using CT colonography |
| Author |
Nobuyuki Shiraga |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Masaaki Hori |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Morio Shimada |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Akira Yamaguchi |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Kazunari Miyamoto |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Ken-ichi Suzuki |
Department of Radiology, Toho University Omori Medical Center |
| Author |
Ehiichi Kohda |
Department of Radiology, Toho University Ohashi Medical Center |
| Author |
Terumitsu Hasebe |
Department of Radiology, Tachikawa Hospital |
| Author |
Mutsumi Higuchi |
Department of Radiology, Tachikawa Hospital |
| Author |
Hidehiko Matsukawa |
Department of Gastroenterology, Tachikawa Hospital |
| Author |
Yoshinoni Sugino |
Department of Diagnostic Radiology, Keio University School of Medicine |
| [ Summary ] |
Advances in the number of z-axis detector-arrays in multidetector-row CT has lead to the practical use of CT colonography (CTC) screening for colorectal lesions. On the other hand, detection and assessment of superficial colorectal lesions, especially superficial depressed type lesions is still difficult using CTC.
There are two ways to detect colorectal lesions with CTC. One is the primary two-dimensional reading method, in which the reader first searches for lesions by examining axial and multiplanar images and then makes a further assessment with three-dimensional images. The other method is the primary three-dimensional reading method, which is the opposite of the two-dimensional primary method. Adenomas as well as most colorectal cancers, including early cancers, may be much more easily observed with IV administration of a contrast medium. Therefore, the sensitivity of imaging for detection of colorectal cancer, employing two-dimensional images is expected to increase with the use of contrast enhancement. In our experience, when detecting superficial depressed lesions, the three-dimensional primary method is more sensitive because these lesions often show minimal wall thickening. Therefore, they are easily overlooked in two-dimensional images even if contrast enhancement is used. With three-dimensional images, slight deformities in the mucosal plane or slight thickening of haustral folds may be clearly observed when detecting superficial depressed type cancer. However, there may be some difficulties with the use of this diagnostic procedure. It requires the reader more time, patience, and experience to eliminate false lesions. A new three-dimensional diagnostic tool, such as colon dissection, will help us to resolve these problems, and lead CTC to become one of the best diagnostic modalities for colorectal lesions. |