CT colonography has advantages over colonoscopy for size measurement of colorectal polyps.

PURPOSE: The aim of this study was to compare the accuracy of colonoscopy (CS) and CT colonography (CTC) in the measurement of colorectal polyps using pathological size as a reference. MATERIALS AND METHODS: The analysis included 61 colorectal polyps in 28 patients who underwent preoperative CTC at our institution. All polyps were endoscopically resected. Polyp sizes were measured by CS and CTC. Endoscopic polyp size was extracted from endoscopy records written by one of two endoscopists (A with 11 and B with 6 years of endoscopic experience, respectively), who estimated the size visually/categorically without any measuring devices. After matching the location, the polyp size was measured on CTC using manual three-dimensional (3D) measurement on a workstation. The sizes of resected polyps were also measured after pathological inspection. Differences of the polyp size between CTC and histology, and between CS and histology were compared using paired t tests. Differences in measurement between the two endoscopists were also analyzed. RESULTS: The mean diameters of polyps measured using CS, CTC, and pathology were 10.5 mm, 9.2 mm, and 8.4 mm, respectively. There was a significant correlation between CS and pathology, as well as between CTC and pathology (both P < 0.0001). The correlation coefficient for CS (r = 0.86) was lower than that for CTC (r = 0.96). The correlations between CS and pathology for endoscopists A and B were 0.90 and 0.89, respectively. CONCLUSION: Measurements of polyp size using CTC were closer to the pathological measurements compared to those by CS, which exhibited greater variability. This suggests that CTC may be more suitable for polyp size measurements in the clinical setting if patients undergo CTC concurrently with colonoscopy.

A case of KIT negative extra-gastrointestinal stromal tumor arising in the greater omentum with predominant cystic formation.

We report a rare case of KIT-negative extra-gastrointestinal stromal tumor, in a 40-year-old woman. Contrast-enhanced computed tomography and magnetic resonance imaging revealed a >15-cm mass of multiple cystic lesions in the greater omentum. Histopathological findings after surgery showed a sheet-like growth of stellate tumor cells from epithelial cells, cystic degeneration, and mucus-like stroma. Immunohistochemistry was positive for discovered on GIST-1 (DOG1) but negative for CD117 (c-kit).

Histopathologic diversity of gastric cancers: Relationship between enhancement pattern on dynamic contrast-enhanced CT and histological type.

PURPOSE: To evaluate the diagnostic value of contrast-enhanced computed tomography gastrography (CE-CTG) to predict the histological type of gastric cancer. MATERIALS AND METHODS: We analyzed 47 consecutive patients with resectable advanced gastric cancer preoperatively evaluated by multiphasic dynamic contrast-enhanced CT. Two radiologists independently reviewed the CT images and they determined the peak enhancement phase, and then measured the CT attenuation value of the gastric lesion for each phase. The histological types of gastric cancers were assigned to three groups as differentiated-type, undifferentiated-type, and mixed-type. We compared the peak enhancement phase of the three types and compared the CT attenuation values in each phase. RESULTS: The peak enhancement was significantly different between the three types of gastric cancers for both readers (reader 1, p=0.001; reader 2, p=0.009); most of the undifferentiated types had peak enhancement in the delayed phase. The CT attenuation values of undifferentiated type were significantly higher than those of differentiated or mixed type in the delayed phase according to both readers (reader 1, p=0.002; reader 2, p=0.004). CONCLUSION: CE-CTG could provide helpful information in diagnosing the histological type of gastric cancers preoperatively.

Diffuse-type gastric cancer: specific enhancement pattern on multiphasic contrast-enhanced computed tomography.

PURPOSE: To evaluate the enhancement pattern of diffuse-type gastric cancers (DGCs) on multiphasic contrast-enhanced computed tomography gastrography (CECTG). METHODS AND MATERIALS: We studied 21 consecutive clinically diagnosed DGC patients who underwent CECTG. Gastric distension was obtained using effervescent granules. CT images were obtained 40 s (arterial phase) and 240 s (delayed phase) after injection of a nonionic contrast material. Two radiologists reviewed the CT images and analyzed layers and enhancement patterns. The readers evaluated the enhancement degree (mild, moderate, or marked) and calculated CT attenuation values by placing circular regions of interest (ROIs) within each layer of the lesion. The CT findings of 11 operated cases were correlated with pathological results. RESULTS: Most lesions were double-layered in the arterial phase, with a moderately enhanced inner layer and a mildly enhanced outer layer, and single-layered in the delayed phase. The mean attenuation value of the inner layer (146 ± 32.8 HU) was significantly higher than that of the outer layer (80.4 ± 15.5 HU) in the arterial phase (p = 0.0001). In the pathological analysis, wall stratification was preserved in nine cases and not preserved in two cases. CONCLUSION: Most DGCs showed a double-layered pattern in the arterial phase and a single-layered pattern with moderate enhancement in the delayed phase.

Diagnosis of early colorectal cancer invasion depth by quantitative evaluation of the basal indentation in CT colonography.

OBJECTIVE: To investigate the feasibility of diagnosing the invasion depth of early colorectal cancer (CRC) by quantitatively evaluating the basal indentation (BI)-i.e., the intestinal lateral deformity-in CT colonography (CTC). MATERIALS AND METHODS: 34 early CRCs (13 Tis CRCs and 21 T1 CRCs) in 32 patients who underwent a preoperative CTC were retrospectively examined. Two radiologists calculated the depth of the BI on a computed tomographic air-contrast enema (CT enema) image, the depth of the BI due to the geometric function (BI-G) on a cross-sectional multiplanar reconstruction (CS-MPR) image, and the ratio of the BI to the BI-G (i.e., the "BI ratio") for each lesion. The BI ratios of the Tis and T1 CRCs were compared. RESULTS: The BI ratios were significantly higher in the T1 CRCs than in the Tis CRCs (p < 0.0001). The optimum cutoff value of the BI ratio for differentiating the T1 CRCs from the Tis CRCs was 1.64, with a sensitivity, specificity, and area under the curve of 90.5 %, 100 %, and 0.974, respectively. CONCLUSIONS: We have demonstrated for the first time that quantitatively evaluating the BI can improve the accuracy of diagnosis of early CRC invasion depth.

Differentiation of early gastric cancer with ulceration and resectable advanced gastric cancer using multiphasic dynamic multidetector CT.

OBJECTIVES: Early gastric cancer with ulceration (EGC-U) mimics advanced gastric cancer (AGC), as EGC-Us and ACGs often have similar endoscopic appearance to ulceration. The purpose of this retrospective study was to determine whether multiphasic dynamic multidetector CT (MDCT) can help differentiate EGC-Us from AGCs. METHODS: Patients with EGC-Us with ulcer stages Ul-III or IV and AGCs with tumour stages T2 to T4a were enrolled. MDCT images were obtained 40 s (arterial phase), 70 s (portal phase) and 240 s (delayed phase) after injection of non-ionic contrast material. Two readers independently measured the attenuation values of the lesions by placing regions of interest. We compared the EGC-Us and AGCs using the mean attenuation values in each phase and peak enhancement phase. We analysed the diagnostic performance of CT for differentiating EGC-Us from AGCs. RESULTS: Forty cases (16 EGC-Us and 24 AGCs) were analysed. The mean attenuation values of the EGC-Us were significantly lower than those of the AGCs in both the arterial and portal phases (all p < 0.0001 for each reader). The peak enhancement was significantly different between the EGC-Us and AGCs for both readers (Reader 1, p = 0.0131; Reader 2, p = 0.0006). CONCLUSION: Multiphasic dynamic contrast-enhanced MDCT can help differentiate EGC-Us from AGCs. KEY POINTS: • Early gastric cancer with ulceration and advanced gastric cancer have similar endoscopic appearances. • EGC-U shows significantly lower attenuation values in both arterial and portal phases. • Multiphasic dynamic contrast-enhanced MDCT differentiates EGC-U from AGC.

A case of pelvic schwannoma presenting prominent eggshell-like calcification.

Pelvic schwannoma typically forms a large, well-circumscribed mass in the retroperitoneum or presacral area and frequently undergoes cystic degeneration. It appears as a well-demarcated round or oval mass, often showing prominent cystic degeneration and calcification. Characteristics of these calcifications are punctate, mottled, or curvilinear and are seen along the walls of the mass. Herein, we describe a case of schwannoma presenting a huge pelvic mass with unique eggshell-like calcification.