A prospective single centre study comparing computed tomography pneumocolon against colonoscopy in the detection of colorectal neoplasms

BACKGROUND AND AIMS: To determine the sensitivity and specificity of computed tomography (CT) pneumocolon in the detection of colorectal neoplasms. METHODS: A total of 201 consecutive patients with colorectal symptoms or requiring surveillance for colorectal neoplasms underwent both conventional colonoscopy and CT pneumocolon. RESULTS: On conventional colonoscopy 13 invasive colorectal carcinomas were detected in 13 patients, and 118 polyps in 63 patients (14 polyps were > or =1 cm in diameter, 25 were 6-9 mm, and 79 were < or =5 mm). CT pneumocolon detected all 13 cancers, two false positive cancers, but only 20 polyps (seven were > or =1 cm). This resulted in a sensitivity of 100% (95% confidence interval (CI) 87-100%) and specificity of 99% (95% CI 97-100%) for detection of invasive carcinoma, and a sensitivity of 73% (95% CI 56-90%) and specificity of 94% (95% CI 91-98%) for detection of invasive carcinoma and/or > or =1 cm polyps. CT pneumocolon also identified invasive carcinoma not seen at colonoscopy because of incomplete examination in three patients, and detected metastases in six colorectal carcinoma patients and extracolonic carcinoma in a further seven patients. CONCLUSIONS: CT pneumocolon had a high sensitivity and specificity for detection of invasive colorectal carcinoma but not colorectal polyps. CT pneumocolon may be suitable for initial investigation of patients with symptoms of colorectal malignancy.     

Multidetector CT in patients with esophageal stent as a palliative treatment for stenosing esophageal cancer: A feasibility study

Objective. The self-expanding metallic stent (SEMS) is widely used in the palliative treatment of stenosing esophageal cancer. Multidetector computed tomography (MDCT) allows volumetric investigation including virtual endoscopy. The aim of this study was to determine the feasibility of MDCT follow-up of esophageal SEMS and to describe the imaging patterns encountered as well as correlating them with fibroscopic evaluation. Material and methods. Thirteen consecutive patients (10 M, mean age 64 years) with esophageal SEMS as a palliative treatment underwent MDCT for recurrent dysphagia (n=7), chest pain and fever (n=1) or follow-up without symptoms (n=5). Patency and esophageal wall patterns were studied and compared with diagnosis by fibroscopy. Results. No metallic artefact related to the SEMS was observed. At the SEMS level, MDCT revealed a tissular lump (n=1), a thin recurrent layer of tissue (n=1), extrinsic compression (n=1), fluid stasis (n=7) and intussusception of the gastric wall into the SEMS (n=4). The esophageal wall was analyzed by MDCT (peripheral thickening around the stent (n=8), tumor overgrowth under or above the SEMS level (n=8)) and showed tracheal compression (n=3). At the level of the SEMS, fibroscopy showed tumor recurrence (n=2), a thin recurrent layer of tissue (n=1), a distorted SEMS (n=1) and a tumor overgrowth under or above the SEMS level (n=6). In comparison with fibroscopy, MDCT satisfactorily diagnosed the SEMS patency in 92% of cases and the esophageal wall in 73%. Conclusions. Morphology, patency of the SEMS and analysis of the esophageal wall can be performed by MDCT with a good degree of accuracy as compared to fibroscopy. In such patients in palliative care, a non-invasive investigation is worth promoting as a first-line procedure.     

Colorectal neoplasm in asymptomatic Asians: a prospective multinational multicenter colonoscopy survey

BACKGROUND: Colorectal neoplasm is rapidly increasing in Asia, but a guideline for screening is not available. OBJECTIVE: To evaluate the characteristics of colorectal neoplasm in asymptomatic Asian subjects. DESIGN: Prospective cohort study. SETTING: Multinational multicenters, including both primary and referral centers in Asia. PATIENTS: A total of 860 consecutive asymptomatic adults undergoing screening colonoscopy in 11 Asian cities from July 2004 to December 2004. Patients under 16 years old; those patients with a colorectal resection history, colonoscopies, or barium enema within 5 years; symptoms suggestive of colorectal diseases; and those who had undergone surveillance colonoscopy were excluded. MAIN OUTCOME MEASUREMENTS: The incidence and distribution of colorectal neoplasm and advanced neoplasm. RESULTS: The mean age (+/-SD) was 54.4+/-11.6 years; 471 were men (54.8%). The prevalence of colorectal neoplasm and advanced neoplasm was 18.5% and 4.5%, respectively. Male sex, advancing age, and a family history of colorectal cancer were risk factors for advanced neoplasm. Of the 168 patients with colorectal neoplasm, 76 had distal neoplasm only (45.2%), 66 had proximal neoplasm only (39.3%), and 26 had both proximal and distal neoplasms (15.5%). Although the presence of distal advanced neoplasm was a significant risk factor for proximal advanced neoplasm, 14 of the 758 subjects without distal neoplasm had proximal advanced neoplasm (1.8%). LIMITATIONS: The small number of enrolled subjects, especially from certain ethnic groups. CONCLUSIONS: The overall prevalence of advanced colorectal neoplasm in asymptomatic Asians is comparable with the West. Male sex, advancing age, and a family history of colorectal cancer were associated with a higher risk of advanced neoplasm.     

Clinical application of computed tomography virtual colography

OBJECTIVE : To investigate the computed tomography (CT) virtual colographic features of colonic polyps, colorectal cancer, diverticula, ulcerative colitis and other benign colonic lesions. Also, to assess the value of this method in the diagnosis of colorectal lesions. METHODS : Computed tomography colography was performed in 37 patients (26 male, 11 female) suffering from the following conditions: 20 colonic adenomas, six colon cancers, four diverticula, five ulcerative colitis and one each of melanosis coli and amyloidosis. The data from CT scanning were processed by computer with specific software and the colonic lesions were evaluated with 2‐ or 3‐D images, depending on the individual software. RESULTS : Seventeen cases of colonic adenoma, six colon cancers, four diverticula and two cases of ulcerative colitis were detected by using CT colography. However, melanosis coli and amyloidosis of the colon were not detected. CONCLUSION : Computed tomography colography can detect all colonic polyps of 0.5 cm in diameter or larger, colon cancer, diverticula and some ulcerative colitis successfully. It is quick, minimally invasive and able to be tolerated well. It has the potential to become an effective radiological tool in diagnosing colonic lesions.     

Computed tomographic virtual colonoscopy computer-aided polyp detection in a screening population

BACKGROUND & AIMS: The sensitivity of computed tomographic (CT) virtual colonoscopy (CT colonography) for detecting polyps varies widely in recently reported large clinical trials. Our objective was to determine whether a computer program is as sensitive as optical colonoscopy for the detection of adenomatous colonic polyps on CT virtual colonoscopy. METHODS: The data set was a cohort of 1186 screening patients at 3 medical centers. All patients underwent same-day virtual and optical colonoscopy. Our enhanced gold standard combined segmental unblinded optical colonoscopy and retrospective identification of precise polyp locations. The data were randomized into separate training (n = 394) and test (n = 792) sets for analysis by a computer-aided polyp detection (CAD) program. RESULTS: For the test set, per-polyp and per-patient sensitivities for CAD were both 89.3% (25/28; 95% confidence interval, 71.8%-97.7%) for detecting retrospectively identifiable adenomatous polyps at least 1 cm in size. The false-positive rate was 2.1 (95% confidence interval, 2.0-2.2) false polyps per patient. Both carcinomas were detected by CAD at a false-positive rate of 0.7 per patient; only 1 of 2 was detected by optical colonoscopy before segmental unblinding. At both 8-mm and 10-mm adenoma size thresholds, the per-patient sensitivities of CAD were not significantly different from those of optical colonoscopy before segmental unblinding. CONCLUSIONS: The per-patient sensitivity of CT virtual colonoscopy CAD in an asymptomatic screening population is comparable to that of optical colonoscopy for adenomas > or = 8 mm and is generalizable to new CT virtual colonoscopy data.     

Virtual colonoscopy for the detection of colorectal polyps and cancers in a Chinese population

AIM: The aim of this study is to assess the sensitivity of virtual colonoscopy in detecting colorectal polyps and cancers in a Chinese population. METHODS: Seventy-one consecutive Chinese patients (38 men and 33 women) referred for diagnostic colonoscopy were recruited. Patients received a routine bowel preparation in the morning followed by a helical abdominal computed tomography (CT) scan with air insufflation of the colon. The CT images were then processed by using surface-rendered software and interpreted by a single radiologist who was blinded to the clinical information. Colonoscopy was performed in the same afternoon without knowledge of the radiology results. All polyps and cancers were proven histologically. RESULTS: Five colorectal cancers were diagnosed and all were detected by virtual colonoscopy. The sensitivity and specificity of virtual colonoscopy for the detection of patients with polyps of all sizes, and patients with polyps >/=10 mm were 59, 92, 88 and 100%, respectively. The procedure was well tolerated by all patients. CONCLUSIONS: This study was carried out in a real clinical setting without a preselection of cases. Virtual colonoscopy was satisfactory for the detection of polyps greater than 10 mm, and for the diagnosis of cancer, and it is also a promising imaging modality for colorectal neoplasm detection in a Chinese population.     

Prediction of anemia on enhanced computed tomography of the thorax using virtual non-contrast reconstructions

To determine if anemia can be predicted on enhanced computed tomography (CT) examinations of the thorax using virtual non-contrast (VNC) images, in order to support clinicians especially in diagnosing primary asymptomatic patients in daily routine.In this monocentric study, 100 consecutive patients (50 with proven anemia), who underwent a contrast-enhanced CT examination of the thorax due to various indications were included. Attenuation was measured in the descending thoracic aorta, the intraventricular septum, and the left ventricle cavity both in the conventional contrast-enhanced and in the VNC images.Two experienced radiologists annotated the delineation of a dense interventricular septum or a hyperattenuating aortic wall sign for all patients.Hemoglobin levels were then correlated with the measured attenuation values, as well as the visualization of the aortic wall or interventricular septum.Good correlation was shown between hemoglobin levels and CT attenuation values of the left ventricular cavity (r = .59), aorta (r = .56), and ratio between left ventricular cavity and the intraventricular septum (r = .57). Receiver operating characteristic curve revealed ≤ 36.5 hounsfield units (left ventricular cavity) as the threshold for diagnosing anemia. Predicting anemia by visualization of a hyperattenuating aortic wall or a dense interventricular septum yielded a specificity of 98% and 92%, respectively.Predicting anemia on enhanced CT examinations using VNC is feasible. A threshold value of ≤ 36.5 hounsfield units (left ventricular cavity) best defines anemia. Aortic wall or interventricular septum visualization on VNC is a specific anemia indicator.     

CT仿真结肠镜与电子结肠镜对结直肠疾病诊断的对照研究

目的探讨CT仿真结肠镜(CTVC)在结直肠疾病,尤其是溃疡性结肠炎诊断中的价值。方法应用螺旋CT对2004年5月至2005年1月就诊于首都医科大学附属北京友谊医院的58例疑诊结直肠病变患者进行容积扫描,获取仿真结肠镜图像,将所得结果与结肠镜结果进行比较分析。结果CTVC检查均获得成功,共检出结直肠癌14例,结直肠息肉15例,溃疡性结肠炎14例,正常者6例。CTVC对结直肠疾病总的敏感性为82.7%(43/52),特异性为100%,准确性为84.5%(49/58),阳性预测值87.8%(43/49),阴性预测值40.0%(6/15),Kappa值为0.497;CTVC对溃疡性结肠炎诊断的敏感性为70.0%(14/20),特异性为100%,准确性为76.9%(20/26),阳性预测值70.0%(14/20),阴性预测值50.0%(6/12),Kappa值为0.519。结论CTVC是一种无创的检查方法,具有一定优势,但仍存在一些弊端,因此对于溃疡性结肠炎诊断仅是一种有效的补充,尚不能完全替代常规结肠镜检查。     

Detection and differentiation of early hepatocellular carcinoma from cirrhosis using CT perfusion in a rat liver model

BACKGROUND: Functional imaging such as CT perfusion can detect morphological and hemodynamic changes in he-patocellular carcinoma (HCC). Pre-carcinoma and early HCC nodules are dififcult to differentiate by observing only their hemodynamics changes. The present study aimed to investi-gate hemodynamic parameters and evaluate their differential diagnostic cut-off between pre-carcinoma and early HCC nod-ules using CT perfusion and receiver operating characteristic (ROC) curves.
METHODS: Male Wistar rats were randomly divided into con-trol (n=20) and experimental (n=70) groups. Diethylnitrosa-mine (DEN) was used to induce pre-carcinoma and early HCC nodules in the experimental group. Perfusion scanning was carried out on all survival rats discontinuously from 8 to 16 weeks. Hepatic portal perfusion (HPP), hepatic arterial frac-tion (HAF), hepatic arterial perfusion (HAP), hepatic blood volume (HBV), hepatic blood lfow (HBF), mean transit time (MTT) and permeability of capillary vessel surface (PS) data were provided by mathematical deconvolution model. The perfusion parameters were compared among the three groups of rats (control, pre-carcinoma and early HCC groups) using the Kruskal-Wallis test and analyzed with ROC curves. Histo-logical examination of the liver tissues with hematoxylin and eosin staining was performed after CT scan.
RESULTS: For HPP, HAF, HBV, HBF and MTT, there were signiifcant differences among the three groups (P<0.05). HAF had the highest areas under the ROC curves: 0.80 (control vs pre-carcinoma groups) and 0.95 (control vs early HCC groups) with corresponding optimal cut-offs of 0.37 and 0.42, respectively. The areas under the ROC curves for HPP was 0.79 (control vs pre-carcinoma groups) and 0.92 (control vs early HCC groups) with corresponding optimal cut-offs of 136.60 mL/min/100 mg and 108.47 mL/min/100 mg, respectively.
CONCLUSIONS: CT perfusion combined with ROC curve analysis is a new diagnosis model for distinguishing between pre-carcinoma and early HCC nodules. HAF and HPP are the ideal reference indices.     

Measurement of aortic diameters and detection of asymptomatic aortic aneurysms in a mass screening program using a mobile helical computed tomography unit

In a mass chest computed tomography (CT) screening using a mobile helical CT unit, we measured the aortic diameter at three segments to confirm standard values and also attempted to detect any asymptomatic aortic aneurysms. The population screened in the present study consisted of 6 971 subjects (3 847 men and 3 124 women, mean age 60.3 ± 12.1 years). They underwent a plain chest CT to screen for lung cancer and tuberculosis. The diameters of the ascending and descending aorta were measured at the level of the pulmonary artery bifurcation. The abdominal aorta was measured at the level of the celiac bifurcation, and the mean values for each measurement were calculated. In addition, we attempted to determine whether any correlation exists among aortic diameter, age, and indices of body size and investigated the frequency of asymptomatic aortic aneurysms among the general population. The mean aortic diameter of all three segments was significantly larger in men than in women and increased with age. It also correlated significantly with indices of body size (P < 0.01). A total of 11 subjects (0.16%) had asymptomatic aortic aneurysms (3 ascending, 4 descending, and 4 thoracoabdominal). The aortic diameter in each individual case was greater than the mean aortic diameter +3 standard deviations in each age group. Chest CT screening for lung cancer can thus detect asymptomatic aneurysms through simultaneous aortic measurement. Received: April 11, 2001 / Accepted: September 22, 2001     

Value of contrast-enhanced 18F-fluorodeoxyglucose positron emission tomography/computed tomography in detection and presurgical assessment of pancreatic cancer: a prospective study

Background and Aim: Positron Emission Tomography (PET) using ¹⁸F‐fluorodeoxyglucose (FDG) associated with computed tomography (CT) is increasingly used for the detection and the staging of pancreatic cancer, but data regarding its clinical added value in pre‐surgical planning is still lacking. The aim of this study is to investigate the performance of FDG PET associated with contrast‐enhanced CT in detection of pancreatic cancer. Methods: We prospectively evaluated FDG PET/CT studies obtained in patients with suspicion of operable pancreatic cancer between May 2006 and January 2008. Staging was conducted according to a standardized protocol, and findings were confirmed in all patients by surgical resection or biopsy examination. Results: Forty‐five patients with a median age of 69 (range 22–82) were included in this study. Thirty‐six had malignant tumors and nine had benign lesions (20%). The sensitivity of enhanced versus unenhanced PET/CT in the detection of pancreatic cancer was 96% versus 72% (P = 0.076), the specificity 66.6% versus 33.3% (P = 0.52), the positive predictive value 92.3% versus 80% (P = 0.3), the negative predictive value 80% versus 25% (P = 0.2), and the accuracy 90.3% versus 64% (P = 0.085). Conclusions: Our preliminary data obtained in a limited number of patients shows that contrast‐enhanced FDG PET/CT offers good sensitivity in the detection and assessment of pancreatic cancer, but at the price of a relatively low specificity. Enhanced PET/CT seems to be superior to unenhanced PET/CT. Further larger prospective studies are needed to establish its value for pre‐surgical diagnosis and staging in pancreatic cancer.     

Validation of virtual colonoscopy in the detection of colorectal polyps and masses: rationale for proper study design

Summary Background. The clinicopathological and biological significance of the expression of iNOS in pancreatic cancer remains unclear. The goal of this study was to determine the possible roles and clinical significance of iNOS expression in pancreatic cancer. Methods. Seventy-two pancreatic adenocarcinoma tissue specimens were obtained by surgical resection. We investigated the immunohistochemical expression of iNOS in 72 patients with pancreatic cancer with respect to variable clinicopathological characteristics, proliferation activity (assessed by Ki-67 expression), apoptosis (assessed by TUNEL stain), and microvessel density (assessed by CD34 expression; angiogenesis). Results. Immunohistochemical investigations demonstrated immunolabeling of tumor cells with anti-iNOS antibody. Positivity for iNOS was observed in 48/72 (66.7%). The expression of iNOS protein did not correlate with age, bilirubin, tumor marker, location, size, AJCC stage, differentiation, distant metastasis, or patient survival. No significanct association was found between iNOS expression and proliferation or microvessel density in pancreatic cancer. Apoptotic index (AI) of positive iNOS expressions were significantly higher than negative expression (p<0.001). Conclusion. Inducible nitric oxide synthase (iNOS) is expressed by human pancreatic cancer, and its presence is positively correlated with apoptosis of cancer cells that could provide the basis for the development of therapeutic strategies in human pancreatic cancer.     

Evaluation of age-related thymic changes using computed tomography images: A retrospective observational study

We aimed to investigate if Computed tomography (CT) attenuation values can help improve the identification of age-related changes in the thymus.We assessed CT images of 405 patients aged 0 to 80 years. We measured the area of the anterior mediastinum at the level of the carina and its average CT attenuation value. We evaluated the thymic area, the ratio of the thymus area to the total thoracic area, and the CT attenuation value. Additionally, we evaluated changes in the thymus area in the 0 to 13-year age group.The area of the thymus decreased from birth to the middle 20s. After the middle 20s, the area tended to increase and plateau till after 50 years of age. The ratio of the thymic area to the thoracic area decreased from age 0 to 20 years, but remained stable after 20 years of age. The CT attenuation values were stable from birth to puberty, decreased after puberty, and were stable again in the late 50s and beyond. The thymus of children showed mass formation, but the shape changed with age. No significant differences in the CT attenuation value were found across underlying conditions for the 0 to 13-year age group.The decrease in the CT attenuation values, observed with advancing age, reflects adipose degeneration of the thymus, indicating that by the late 50s, thymic tissue is replaced completely by adipose tissue. Our data suggest that adipose degeneration of the thymus begins after puberty and advances with age.     

Computed tomography in diagnosing vascular invasion in pancreatic and periampullary cancers: a systematic review and meta-analysis

BACKGROUND: Preoperative diagnosis of local vascular invasion is very important to the selection of therapeutic protocols and prediction of the prognosis of pancreatic and periampullary cancers. This meta-analysis was designed to evaluate the accuracy of computed tomography (CT) in diagnosing vascular invasion in patients with pancreatic and periampullary cancers. DATA SOURCES: English-language articles reporting diagnostic accuracy of CT for vascular invasion in pancreatic and periampullary cancers were se...     

Virtual gastrointestinal colonoscopy in combination with large bowel endoscopy: Clinical application

Although colorectal cancer (CRC) has no longer been the leading cancer killer worldwide for years with the exponential development in computed tomography (CT) or magnetic resonance imaging, and positron emission tomography/CT as well as virtual colonoscopy for early detection, the CRC related mortality is still high. The objective of CRC screening is to reduce the burden of CRC and thereby the morbidity and mortality rates of the disease. It is believed that this goal can be achieved by regularly screening the average-risk population, enabling the detection of cancer at early, curable stages, and polyps before they become cancerous. Large-scale screening with multimodality imaging approaches plays an important role in reaching that goal to detect polyps, Crohn’s disease, ulcerative colitis and CRC in early stage. This article reviews kinds of presentative imaging procedures for various screening options and updates detecting, staging and re-staging of CRC patients for determining the optimal therapeutic method and forecasting the risk of CRC recurrence and the overall prognosis. The combination use of virtual colonoscopy and conventional endoscopy, advantages and limitations of these modalities are also discussed.