Unenhanced Areas Revealed by Contrast-Enhanced Abdominal Ultrasonography with Sonazoidtm Potentially Correspond to Colorectal Cancer
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4012 EXPERIMENTAL AND THERAPEUTIC MEDICINE 12: 4012-4016, 2016 Unenhanced areas revealed by contrast-enhanced abdominal ultrasonography with SonazoidTM potentially correspond to colorectal cancer MINORU TOMIZAWA1, MIZUKI TOGASHI2, FUMINOBU SHINOZAKI3, RUMIKO HASEGAWA4, YOSHINORI SHIRAI4, MIDORI NORITAKE2, YUKIE MATSUOKA2, HIROAKI KAINUMA2, YASUJI IWASAKI2, KAZUNORI FUGO5, YASUFUMI MOTOYOSHI6, TAKAO SUGIYAMA7, SHIGENORI YAMAMOTO8, TAKASHI KISHIMOTO5 and NAOKI ISHIGE9 Departments of 1Gastroenterology; 2Clinical Laboratory; 3Radiology and 4Surgery, National Hospital Organization, Shimoshizu Hospital, Yotsukaido City, Chiba 284-0003; 5Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba City, Chiba 260-8670; Departments of 6Neurology; 7Rheumatology; 8Pediatrics and 9Neurosurgery, National Hospital Organization, Shimoshizu Hospital, Yotsukaido, Yotsukaido City, Chiba 284-0003, Japan Received September 18, 2015; Accepted September 22, 2016 DOI: 10.3892/etm.2016.3868 Abstract. The present study investigated the potential utility of Introduction contrast-enhanced abdominal ultrasonography (CEUS), using SonazoidTM, in colorectal cancer (CRC). Three patients were Colorectal cancer (CRC) is commonly observed in clinical subjected to CEUS with SonazoidTM. Surgical specimens were settings (1). To improve the prognosis in patients with CRC, immunostained for CD31. Numbers of blood vessels positive prompt and accurate diagnosis is essential. Screening for CRC for CD31 were analyzed in each of five fields at x400 magnifi- is performed using fecal occult blood testing, and is diagnosed cation and averaged to determine blood vessel density. Blood with colonoscopy (2). vessel density was compared between non-tumorous and Abdominal ultrasound (US) is useful for the safe and tumorous areas. Prior to the administration of SonazoidTM, easy diagnosis of patients (3-6). During US screening of the CRC was illustrated as irregular-shaped wall thickening. One abdomen, CRC is sometimes encountered (7). A thickened minute after the administration of SonazoidTM, the majority colonic wall has been reported as a criteria for the diagnosis of the thickened wall was enhanced, while some parts of the of CRC (8). Changes in stratification and contour illustrated thickened wall remained unenhanced. Blood vessel densities of with abdominal US are associated with the depth of invasion, non-tumorous and tumorous areas in patient two were 25.2±2.5 in either the subserosa or the extra subserosa (7). and 5.2±1.1 (P<0.0001). Blood vessel densities of non-tumorous Contrast-enhanced ultrasonography (CEUS) enables the and tumorous areas in patient three were 19.0±3.1 and 2.2±0.8 evaluation of tissue vascularity with low blood flow velocity (9). (P<0.0001). Tumorous areas of CRC were not enhanced 1 min Primary or metastatic liver tumors are the most common after the administration of SonazoidTM. Blood vessel density indication examined by CEUS (10,11). Regarding the alimen- was lower in tumorous areas compared with non-tumorous tary tract, guidelines put forth by the European Federation of areas, as evidenced by immunohistochemistry for CD31. These Societies for Ultrasound in Medicine and Biology recommend findings suggest that CEUS may be useful for the determina- use of CEUS in inflammatory bowel disease for diagnosis, tion of the extent of CRC. activity assessment, and examining complications such as stenosis or fistula (9). In addition, CEUS is useful for the diag- nosis of gastrointestinal bleeding (12). SonazoidTM consists of perfluorocarbon microbubbles with a median diameter ≤3 mm, which are stable during examination Correspondence to: Dr Minoru Tomizawa, Department of and act as a strong contrast agent (13). SonazoidTM is primarily Gastroenterology, National Hospital Organization, Shimoshizu used for the management of hepatocellular carcinoma, while no Hospital, 934-5 Shikawatashi, Yotsukaido City, Chiba 284-0003, TM Japan reports yet exist regarding the use of Sonazoid in CRC (14,15). E-mail: [email protected] In the present study, we analyzed CEUS images using SonazoidTM to examine its usefulness in the diagnosis of CRC. Key words: SonazoidTM, perfluorocarbon microbubbles, colorectal Blood vessel density was compared between tumorous areas cancer, cluster of differentiation 31, blood vessel, density and non-tumorous areas and supplemented by immunostaining for cluster of differentiation (CD)31, a pan-endothelial cell marker (16). TOMIZAWA et al: SONAZOIDTM FOR COLORECTAL CANCER 4013 Materials and methods and photographed under an AX80 microscope (Olympus Corporation, Tokyo, Japan). To determine blood vessel density, Patients. Between August 2011 and May 2015, 13 patients the number of blood vessels staining positive with CD31 were were diagnosed with CRC using US screening at the National counted per field at x400 magnification under the microscope. Hospital Organization Shimoshizu Hospital (Yotuskaido, The number of positive blood vessels across five fields for each Japan). Of those, three patients were subjected to CEUS with patient was examined and the average determined. SonazoidTM to examine for liver metastasis. In all cases, CRC was observed prior to examination for liver metastasis. The Statistical analysis. Blood vessel densities were compared study was approved by the National Hospital Organization between tumorous areas and corresponding non-tumorous areas Shimoshizu Hospital Ethics Committee, and written informed by using a one-factor analysis of variance. Statistical analysis consent was obtained from all three patients. All procedures was performed using JMP 10.0.2 software (SAS Institute, Cary, followed were in accordance with ethical standards put forth by NC, USA). P<0.05 was considered to indicate a statistically the responsible institutional and national committees on human significant difference. experimentation, and with the Helsinki Declaration of 1964 and later versions. Patient characteristics are listed in Table I. Results Clinical parameters analyzed by blood tests were white blood cell count, hemoglobin, C-reactive protein, carcinoembryonic Contrast-enhanced ultrasonography of colorectal cancer. Prior antigen and carbohydrate antigen 19-9. to the administration of SonazoidTM, a thickened colonic wall Patients two and three consented to further investigation, with an irregular shape was observed in patients one, two and and agreed to provide surgical specimens for analysis. three, as shown in Fig. 1A-C, respectively. One minute after administration, most of the thickened wall was enhanced in Abdominal US and administration of SonazoidTM. Abdominal patients one, two and three, as shown in Fig. 1D-F, respectively, US was performed by Senior Fellows of the Japan Society of with some parts of the thickened wall remaining unenhanced Ultrasonics in Medicine using a SSA-700A US system (Toshiba (indicated by arrows). Ten minutes after the administration of Medical Systems Corporation, Ohtawara, Japan) with a 3.75-MHz SonazoidTM, the enhanced areas of the thickened wall returned curved-array probe (PVT-375BT; Toshiba Medial Systems to a hypoechoic state in patients one, two and three, depicted Corporation) or an 8.0-MHz linear-array probe (PLT-805AT; in Fig. 1G-I, respectively. The shapes of the unenhanced areas Toshiba Medical Systems Corporation). SonazoidTM (Daiichi resembled those of tumorous areas identified in post‑surgical Sankyo Co., Ltd., Tokyo, Japan) was administered intravenously samples from patients two (Fig. 1J) and three (Fig. 1K). These at 0.015 ml/kg following the manufacturer's instruction. results suggest that areas remaining unenhanced 1 min after the administration of SonazoidTM may be tumorous. It might be Criteria for the diagnosis of CRC. The diagnostic criteria postulated that the blood vessel density was lower in tumorous for CRC used were localized irregular wall thickening or a areas compared with surrounding non-tumorous areas. hypoechoic mass mixed with hyperechoic lesions (a pseu- dokidney sign) (8). The former is a common finding in patients Vascular structure of colorectal cancer. To compare the blood with CRC (17), and the latter represents tumor tissue with air in vessel densities between tumorous areas and the surrounding the residual lumen (18). non-tumorous areas, immunostaining with an antibody to CD31 was performed. Varieties of blood vessel sections were observed Pathological analysis and immunostaining. The depth of inva- (Fig. 2A). Specimens remained negative in the absence of incu- sion by the CRC was determined by pathologists analyzing bation with anti-CD31 antibody (Fig. 2B). All positive signals specimens obtained via surgical resection, using standard observed were thought to be blood vessels. Surgical specimens histological methods. Immunostaining proceeded as follows. from patients two (Fig. 2C and D) and three (Fig. 2E and F) Serial sections were cut from formalin‑fixed paraffin‑embedded were subjected to anti-CD31 immunostaining. Non-tumorous surgical samples. The sections were deparaffinized, and auto- areas (Fig. 2C and E) exhibited more positive signals compared claved in 0.05 M citrate buffer at pH 6.0. Endogenous peroxidase with tumorous areas (Fig. 2D and F). Measurements of blood was inactivated by incubating with 0.1% hydrogen peroxide in vessel densities for non-tumorous areas and tumorous areas 100% methanol for 30 min at 4˚C. To prevent non‑specific anti- in patient two (25.2±2.5 and 5.2±1.1, respectively) were found body binding, the