CT colonography: computer-assisted detection of colorectal cancer.

OBJECTIVES: Computer-aided detection (CAD) for CT colonography (CTC) has been developed to detect benign polyps in asymptomatic patients. We aimed to determine whether such a CAD system can also detect cancer in symptomatic patients. METHODS: CTC data from 137 symptomatic patients subsequently proven to have colorectal cancer were analysed by a CAD system at 4 different sphericity settings: 0, 50, 75 and 100. CAD prompts were classified by an observer as either true-positive if overlapping a cancer or false-positive if elsewhere. Colonoscopic data were used to aid matching. RESULTS: Of 137 cancers, CAD identified 124 (90.5%), 122 (89.1%), 119 (86.9%) and 102 (74.5%) at a sphericity of 0, 50, 75 and 100, respectively. A substantial proportion of cancers were detected on either the prone or supine acquisition alone. Of 125 patients with prone and supine acquisitions, 39.3%, 38.3%, 43.2% and 50.5% of cancers were detected on a single acquisition at a sphericity of 0, 50, 75 and 100, respectively. CAD detected three cancers missed by radiologists at the original clinical interpretation. False-positive prompts decreased with increasing sphericity value (median 65, 57, 45, 24 per patient at values of 0, 50, 75, 100, respectively) but many patients were poorly prepared. CONCLUSION: CAD can detect symptomatic colorectal cancer but must be applied to both prone and supine acquisitions for best performance.

A simple image processing approach for electronic cleansing in computed tomographic colonography.

The prevalence of colon cancer has seen strong demand in screening for colorectal neoplasia, and this has drawn considerable attention to the technological advances in Computed Tomographic Colonography (CTC). With the assistance of an oral contrast agent, an imaging technique known as Electronic Cleansing (EC), can affect virtual cleaning of the computed tomography (CT) images, to remove fecal material that is tagged by the agent. Technical problems can arise with electronic cleansing however, when the air lumen causes distortions to the tagged regions which result in partial volume effects.Combining the simple image arithmetic of an electronic cleansing algorithm, with a vertical motion filter at the fluid level of the bowel, artifacts such as those caused by an air lumen are eliminated. Essentially, the filter becomes a vector for that carries the measurement of vertical motion to neutralise the artifact that is causing partial volume effects. Results demonstrate that despite its simplicity, this technique offers accuracy and is able to successfully maintain the normal intra-colonic structure, while supporting digital leaning of tagged residual material appearing on the colon wall.

A new approach towards volumetric assessment of left ventricular function with MSCT.

Cardiovascular CT is considered the diagnostic standard for establishing the presence of a functional and dynamic imaging system. It is difficult, however, to estimate the ventricular motion and volumes that are processed using hundreds and thousands of CT images, in a few moments.The main concept and design of our work are two fold - the development of effective semi-automatic tools for measuring the sequential left ventricular volumes from the hundreds or thousands of cardiac trans-axial images, and providing a simple interface with an interactive diagnostic tool for the volumetry of left ventricle and valuable cardiac 4D visualisation.We converted ten and more sequential volume data sets of the heart acquired from retrospective ECG-gating helical scan into 3D images by volume rendering. These sequential 3D images could be displayed as a movie (4D cardiac image) file. Furthermore, we developed a method for semi-automatic calculation of ejection fraction (EF) and cardiac cycle (%)-volume (ml) curve for estimation of the motion and the volume of the left ventricle. This method involved the use an interactive selection tool in the region of interest (ROI). All 3D processing methods, such as, cutting objects, segmentation, and image fusion were based on mask processing data. We now describe the software developed for cardiac 4D imaging and the estimation of ventricular volume.

Early invasive colorectal carcinomas with submucosal invasion: radiographic characteristics with barium double contrast images.

BACKGROUND: We assessed the radiographic characteristics of early colorectal carcinomas with submucosal invasion (CCSI) with the use of double-contrast images. METHODS: From 1989 to 1997, 193 patients with 196 CCSI lesions underwent double-contrast barium enema examinations. Three gastrointestinal radiologists retrospectively reviewed the radiographic characteristics of the lesions and classified them as protruding and depressed types by consensus. Further, subclassifying the protruding into lobular and smooth types was accomplished on the basis of surface structure. Each type was compared with pathologic findings of resected specimens. RESULTS: The incidence of the protruding type was 98.0%, and that of the depressed type was only 2.0%. The proportion of smooth lesions was 49.0% for the protruding type; these had a mean diameter of 17.9 mm, which was significantly smaller than the 23.1 mm mean observed for lobular lesions (p < 0.01). Of the smooth lesions, 44.7% demonstrated massive invasion, whereas 91.8% of lobular lesions exhibited only slight or moderate invasion into the submucosa (p < 0.01). The extent of invasion of the smooth lesions was greater than that for their lobular counterparts in terms of venous and lymph node involvement. CONCLUSION: Almost all CCSIs could be identified radiologically as protruding lesions; these had a smooth rather than a lobulated surface and demonstrated greater malignancy, despite the smaller size. It is clinically important to discriminate these from other polypoid lesions in establishing patient treatment. Double-contrast imaging is useful for evaluation of the surface characteristics of CCSIs in barium enema studies.

Surgical therapy for recurrent esophageal cancers at anastomoses after esophagectomy.

BACKGROUND/AIMS: The long-term prognosis of a recurrent esophageal cancer at the anastomosis after esophagectomy is generally unfavorable. We have experienced six cases in our institute where surgical treatment resulted in a good prognosis. METHODOLOGY: Between 1962 and 1997, 1720 patients underwent esophagectomy for esophageal cancers in our institute. Anastomotic recurrence was identified in 13 and surgical therapy was performed for six of these. Their clinical and histopathological features were examined with reference to control of anastomotic recurrent esophageal cancers. RESULTS: The six patients were all males with an average age of 61.5 years. Their median disease-free interval was 5.5 months. Three patients lived more than five years after the first esophagectomy. Histopathologically, regional lymph node metastases were found in four of the cases and cervical lymph node metastases were detected in two at the initial esophagectomy. Vessel invasion was evident in three cases, intraepithelial spread in one, and multiple cancers in two. There were no cases with intramural metastasis. Radiotherapy and/or chemotherapy were added for three cases. CONCLUSIONS: After esophagectomy for esophageal cancers, frequent examination of the anastomotic site using endoscopy and long-term follow-up studies are desirable. The option of surgery should not be ignored when a recurrent cancer appears only at the anastomosis.

Diagnosis of gastric cancers: comparison of conventional radiography and digital radiography with a 4 million-pixel charge-coupled device.

PURPOSE: To evaluate the differences in accuracy and observer performance at conventional radiography and at digital radiography with a 4 million-pixel charge-coupled device (CCD) for the diagnosis of gastric cancers. MATERIALS AND METHODS: A prospective study was performed of 225 patients with suspected gastric cancer who were referred to our hospital from January 1997 through February 1997. One hundred twelve patients were examined at conventional radiography and 113 were examined at digital radiography, and 24 and 27 patients had gastric cancer, respectively. Six radiologists interpreted the images, with attention to tumor findings. They were blinded to the clinical details, and their interpretations were rated against those of three other radiologists who examined the patients and who were aware of the clinical information such as endoscopic features and/or histopathologic findings in biopsy specimens. Receiver operating characteristic (ROC) analysis was used to compare the differences in observer performance for the diagnosis of gastric cancers at conventional radiography and at digital radiography. RESULTS: The overall sensitivity was 64.6% at conventional radiography versus 75.3% at digital radiography (P =. 287); specificities were 84.5% and 90.5%, respectively (P =.011); and the positive predictive values were 53.1% and 71.3%, respectively (P =.036). ROC analysis clearly showed higher diagnostic performance at digital radiography than at conventional radiography. CONCLUSION: The data demonstrate the high diagnostic value of digital radiography with a 4 million-pixel CCD for gastric cancers. The technique has considerable potential as an alternative to conventional gastrointestinal radiography.

Abdominal actinomycosis: barium enema and computed tomography findings.

A case of abdominal actinomycosis is described in a woman with recurrent right lower abdominal pain and low-grade fever without history of appendectomy. Past history included the use of an intrauterine device (IUD) until 10 years before manifestation of these symptoms. We followed up the patient, via diagnostic imaging, for 7 months. On initial barium enema, a polypoid lesion was visualized at the bottom of the cecum and there was constriction of the sigmoid colon; the appendix was not seen. Seven months later, poor extension at the cecum, severe constriction in the sigmoid colon, and narrowing of the terminal ileum were also visualized. On computed tomography (CT), the lesion was initially localized only in the ileocecal region adjacent to the sigmoid colon. After 7 months, the lesion had infiltrated adjacent anatomic components and showed direct infiltration of the pelvic space. Differential diagnosis was difficult, as it was not obvious whether this was a pelvic abscess due to inflammation or appendiceal carcinoma. Laparotomy was performed. Macroscopically, the lesion was not limited to the ileocecal region, but involved the right ureter, tubes the Fallopian and ovary, bladder, psoas muscle, and abdominal wall. Pathology findings showed, chronic inflammatory tissue with evidence of actinomycosis. Although previous reports have described a lack of specific findings in this disease. When actinomycosis is suspected, CT is recommended to define its extent.

Lipiodol retention and massive necrosis after lipiodol-chemoembolization of hepatocellular carcinoma: correlation between computed tomography and histopathology.

This retrospective study examined the computed tomography (CT) criteria for judging the effectiveness of transcatheter arterial Lipiodol-chemoembolization (Lp-chemo-TAE) in 35 cases with hepatocellular carcinoma (HCC). Massive necrosis, defined as involving 97% or more of the HCC nodule, was observed in 15 cases after Lp-chemo-TAE, whereas nonmassive necrosis, defined as involving < or = 96% of the HCC nodule, was observed in the remaining 20 cases. In 12 of 15 cases (80%) with massive necrosis, uniform dense retention of Lipiodol (Lp) was observed throughout the HCC nodule on CT images 3-4 weeks after Lp-chemo-TAE as opposed to only one (5%) of 20 cases with nonmassive necrosis (p < 0.01). Eight of nine cases (89%) with massive necrosis had tumor attenuation values of 365 Hounsfield units (HU) or greater on CT images 3-4 weeks after embolization, as opposed to only four (27%) of 15 cases with nonmassive necrosis (p < 0.01). We conclude that the effectiveness of the Lp-chemo-TAE can be judged on CT from the degree and duration of Lp retention in the HCC nodule and the measurement of the attenuation value of the HCC nodule.

Rupture of hepatocellular carcinoma: predictive value of CT findings.

To assess the value of CT in predicting spontaneous rupture of hepatocellular carcinoma, we reviewed CT scans obtained within 3 months before the rupture of hepatocellular carcinoma in 23 patients (rupture group) and within 3 months before death of any cause other than rupture of hepatocellular carcinoma in 20 patients with tumor contacting or protruding out of the liver margins (nonrupture group). All the carcinomas in the rupture group were located in the periphery of the liver. They protruded out of the liver margins in 18 cases and contacted the liver margins without protrusion in five cases. For the rupture and nonrupture groups, respectively, mean numbers of involved liver segments were 4.2 +/- 2.3 and 2.3 +/- 1.3 (p less than .01); mean maximal tumor areas were 102.0 +/- 57.0 cm2 and 57.7 +/- 50.9 cm2 (p less than .05); frequencies of tumor protrusion was 78% and 50% (NS); mean maximal lengths of protruded margins of the tumor were 188.1 +/- 81.4 mm and 77.2 +/- 50.3 mm (p less than .01); frequencies of extrahepatic invasion of the tumor were 44% and 20% (NS); and frequencies of ascites were 78% and 50% (NS). No significant differences in age or sex of the patients and clinical stage of the cancer were evident between the two groups. Multiple regression analysis (p less than .005, r2 = .428) indicated that, of the CT findings, maximal length of protrusion correlated best (p less than .05) with subsequent rupture. We conclude that increased tumor size and extent of extrahepatic protrusion are associated with an increased risk for rupture of hepatocellular carcinoma.

Gallium-67 citrate scintigraphy in the pre-operative evaluation of soft tissue tumors of the extremities.

We conducted a study of 90 patients with soft tissue tumor in their arms or legs, in order to determine the usefulness of scintigraphy with gallium-67 citrate as a diagnostic means. All patients had adequate scan images, and tumor tissues had been histologically confirmed by surgical resection. The subjects consisted of 19 patients with malignant tumors, 55 patients with benign tumors, and 16 patients with other disorders in which soft tissue tumor-like lesions occurred. When the activity of the tumor was more than the activity of the normal region of the contralateral extremity, it was estimated to be positive. The positive rate was found in 78% (15/19) of patients with malignant tumors, in 25% (14/55) of patients with benign tumors and in 31% (5/16) of patients with other disorders. Classified by diseases, high positive rates were observed in liposarcoma, leiomyosarcoma, malignant lymphoma, neurinoma, extra-abdominal desmoid and sarcoidosis. Out of 7 patients in which the activity of the tumor was equal to, or higher than that of the liver, 6 patients had malignant tumors and one patient was diagnosed as having an abscess. It seemed possible to distinguish between liposarcoma and lipoma by means of a gallium-67 scan. Furthermore, the gallium-67 scan was useful in detecting lesions of sarcoidosis as well as in evaluating the response to treatment.

Leiomyosarcoma of the duodenum.

Leiomyosarcoma of the duodenum is a rare disease and its characteristics have been described previously in the literature. We present a case of duodenal leiomyosarcoma, which was diagnosed by several imaging techniques prior to operation. Findings of computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, and angiography in this case are discussed.

A case of intermittent bleeding Meckel's diverticulum.

The initial technetium-99m pertechnetate abdominal scintigraphy revealed equivocal or normal results. However, a second scintigraphy without pentagastrin demonstrated a focal area of persistently increasing radioactivity in the right lower quadrant of the abdomen. At surgery, Meckel's diverticulum was confirmed, and histological examination of the excised specimen revealed that it was lined with ectopic gastric mucosa. It has not been satisfactorily explained why the initial imaging failed to demonstrate the ectopic gastric mucosa. The necessity to perform repeated scintigraphy must be emphasized because 50 to 91 percent of bleeding Meckel's diverticula in the pediatric age group are said to contain gastric mucosa.

[A case of gastric lipoma diagnosed preoperatively].

A case of gastric lipoma seen in a 57-year-old-woman was reported. UGI, endoscope, CT, MRI and EUS revealed a tumor, which showed typical findings of this disease. Above all, EUS findings correlated well with the cut surface of the operative specimen.

[A case of hepatocellular carcinoma with a duodenal invasion from metastatic lymph node].

A 64-year-old male, who had been diagnosed as having hepatocellular carcinoma, was admitted to hospital and underwent transcatheter arterial infusion therapy. CT and US examinations revealed a large tumor with air in its center. Barium meal examination of the duodenum showed a large filling defect with a central excavation. At endoscopic examination, a dark reddish tumor was seen protruding into the duodenal lumen. A biopsy specimen from this tumor revealed a hepatocellular carcinoma. The patient subsequently died of hepatic coma following gastrointestinal bleeding. An autopsy revealed that metastatic lymph nodes had infiltrated into the adjacent duodenum. Nine previous cases of duodenal metastasis from a hepatocellular carcinoma have been reported in the Japanese literature.