Performance of multidetector computed tomography colonography compared with conventional colonoscopy.
(1/182)
BACKGROUND AND AIMS: This was a prospective blinded study to compare computed tomography (CT) colonography, performed with multidetector arrays CT scan (MDCT), with conventional colonoscopy for the detection of colorectal neoplasia. METHODS: Fifty patients were examined by MDCT after standard bowel preparation and rectal air insufflation in the supine and prone positions. Data sets were examined by one radiologist and one gastroenterologist blinded to the patient's history and colonoscopy results. Patients subsequently underwent colonoscopy on the same day, which served as the gold standard. RESULTS: Nine of 11 lesions >10 mm (82%), 5/15 lesions of 6-9 mm (33%), and 1/42 polyps <5 mm (3%) were detected by MDCT colonography. One false positive result for a structure larger than 10 mm was described. Nineteen of 21 patients who had no lesions during conventional colonoscopy were considered free of lesions by MDCT colonography, yielding a per patient specificity of 90%. CONCLUSION: MDCT colonography provides good data quality and has good sensitivity and specificity for the detection of colonic lesions of 10 mm or more. (+info)
Virtual endoscopy: a promising new technology.
(2/182)
Growing evidence shows that early detection of cancer can substantially reduce mortality, necessitating screening programs that encourage patient compliance. Radiology is already established as a screening tool, as in mammography for breast cancer and ultrasonography for congenital anomalies. Advanced processing of helical computed tomographic data sets permits three-dimensional and virtual endoscopic models. Such models are noninvasive and require minimal patient preparation, making them ideal for screening. Virtual endoscopy has been used to evaluate the colon, bronchi, stomach, blood vessels, bladder, kidney, larynx, and paranasal sinuses. The most promising role for virtual endoscopy is in screening patients for colorectal cancer. The technique has also been used to evaluate the tracheobronchial tree for bronchogenic carcinoma. Three-dimensional and virtual endoscopy can screen, diagnose, evaluate and assist determination of surgical approach, and provide surveillance of certain malignancies. (+info)
Computer-aided detection and diagnosis at the start of the third millennium.
(3/182)
Computer-aided diagnosis has been under development for more than 3 decades. The rate of progress appears exponential, with either recent approval or pending approval for devices focusing on mammography, chest radiographs, and chest CT. Related technologies improve diagnosis for many other types of medical images including virtual colonography, vascular imaging, as well as automated quantitation of image-derived metrics. A variety of techniques are currently employed with success, likely reflecting the variety of imagery used, as well as the variety of tasks. Most areas of medical imaging have had efforts at computer assistance, and some have even received FDA approval and can be reimbursed. We anticipate that the rapid advance of these technologies will continue, and that application will broaden to cover much of medical imaging. Acceptance of, and integration of computer-aided diagnosis technology with the electronic radiology practice is a current challenge. These challenges will be overcome, and we expect that computer-aided diagnosis will be routinely applied to medical images. (+info)
Current and evolving strategies for colorectal cancer screening.
(4/182)
BACKGROUND: Colorectal cancer is a major cause of cancer mortality and morbidity. Screening can potentially prevent most colorectal cancers by detection and removal of precursor adenomas. METHODS: The literature and clinical practice guidelines are reviewed, with an emphasis on advances of the last 10 years and evolving screening methods. RESULTS: Colonoscopy has come to be used for screening in persons at average risk for colorectal cancer because of the comparative ineffectiveness of other methods, although these methods continue to be recommended. Virtual colonoscopy and fecal DNA testing are emerging technologies with promise to be more effective than fecal occult blood testing or sigmoidoscopy in selecting those persons who should undergo colonoscopy. Next to age, family history is the most common risk factor for colorectal cancer and one that warrants more aggressive screening and, in some instances, genetic counseling and testing. Hereditary nonpolyposis colorectal cancer accounts for as many as 1 in 20 colorectal cancers, but to take advantage of recent advances in genetic testing for this disorder, a high level of clinical suspicion must be maintained. CONCLUSIONS: If we are to reduce mortality and morbidity from colorectal cancer, practicing clinicians need to be aware of current and evolving strategies for colorectal screening, and assertively recommend the appropriate strategy to their patients. (+info)
Chemotherapy and surgery: new perspectives on the treatment of unresectable liver metastases.
(5/182)
Liver metastases concern half of patients with colorectal cancer, and are frequently unresectable, jeopardizing patient outcome. Owing to increased efficacy, chemotherapy can render initially inoperable patients amenable to potentially curative resection. The 34% 5-year and 20% 10-year survival of patients resected following neoadjuvant chronomodulated chemotherapy with 5-fluorouracil, folinic acid and oxaliplatin is similar to that of patients whose disease was operable at diagnosis. Recently, a group of 16 patients were treated with irinotecan and became resectable after treatment. Their survival (56% at 3 years) matches that of patients treated with other forms of chemotherapy. The poor prognosis of patients with non-resectable hepatic metastases might now be improved by the combination of chemotherapy and surgery. (+info)
Extracolonic findings at computed tomography colonography are a challenge.
(6/182)
AIM: Our aim was to perform a prospective evaluation of the frequency and diagnostic consequences of extracolonic findings at multidetector array computed tomography colonography (MDCTC) in asymptomatic patients undergoing surveillance for former colorectal polyps or cancer. PATIENTS AND METHODS: Seventy five consecutive patients undergoing surveillance for former colorectal cancer (CRC) or large bowel adenoma were examined with MDCTC. Two independent observers evaluated the images with regard to extracolonic findings. Patient records and radiological information systems were reviewed to determine the results and consequences of the workup derived from MDCTC. RESULTS: Sixty five per cent (95% confidence interval (CI) 55-73%) of patients had extracolonic abnormalities and in 12% (CI 7-18%) of patients additional workup was indicated. Two patients (3% (CI 1-6%)) underwent surgery because of the findings (one) or because of complications of the workup (one). CONCLUSION: MDCTC identifies a large number of extracolonic findings. Approximately 12% of asymptomatic patients undergo additional workup, of benefit to only a few. The high prevalence of extracolonic findings may make MDCTC a problematic colorectal screening tool for both ethical and economic reasons. (+info)
Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults.
(7/182)
BACKGROUND: We evaluated the performance characteristics of computed tomographic (CT) virtual colonoscopy for the detection of colorectal neoplasia in an average-risk screening population. METHODS: A total of 1233 asymptomatic adults (mean age, 57.8 years) underwent same-day virtual and optical colonoscopy. Radiologists used the three-dimensional endoluminal display for the initial detection of polyps on CT virtual colonoscopy. For the initial examination of each colonic segment, the colonoscopists were unaware of the findings on virtual colonoscopy, which were revealed to them before any subsequent reexamination. The sensitivity and specificity of virtual colonoscopy and the sensitivity of optical colonoscopy were calculated with the use of the findings of the final, unblinded optical colonoscopy as the reference standard. RESULTS: The sensitivity of virtual colonoscopy for adenomatous polyps was 93.8 percent for polyps at least 10 mm in diameter, 93.9 percent for polyps at least 8 mm in diameter, and 88.7 percent for polyps at least 6 mm in diameter. The sensitivity of optical colonoscopy for adenomatous polyps was 87.5 percent, 91.5 percent, and 92.3 percent for the three sizes of polyps, respectively. The specificity of virtual colonoscopy for adenomatous polyps was 96.0 percent for polyps at least 10 mm in diameter, 92.2 percent for polyps at least 8 mm in diameter, and 79.6 percent for polyps at least 6 mm in diameter. Two polyps were malignant; both were detected on virtual colonoscopy, and one of them was missed on optical colonoscopy before the results on virtual colonoscopy were revealed. CONCLUSIONS: CT virtual colonoscopy with the use of a three-dimensional approach is an accurate screening method for the detection of colorectal neoplasia in asymptomatic average-risk adults and compares favorably with optical colonoscopy in terms of the detection of clinically relevant lesions. (+info)
Postprocessing techniques of CT colonography in detection of colorectal carcinoma.
(8/182)
AIM: To evaluate the value of postprocessing techniques of CT colonography, including multiplanar reformation (MPR), virtual colonoscopy (VC), shaded surface display (SSD) and Raysum, in detection of colorectal carcinomas. METHODS: Sixty-four patients with colorectal carcinoma underwent volume scanning with spiral CT. MPR, VC, SSD and Raysum images were obtained by using four kinds of postprocessing techniques in workstation. The results were comparatively analyzed according to circumferential extent, lesion length and pathology pattern of colorectal carcinomas. All diagnoses were proved pathologically and surgically. RESULTS: The accuracy of circumferential extent of colorectal carcinoma determined by MPR, VC, SSD and Raysum was 100.0%, 82.8%, 79.7% and 79.7%, respectively. There was a significant statistical difference between MPR and VC. The consistent rate of lesion length was 89.1%, 76.6%, 95.3% and 100.0%, respectively. There was a statistical difference between VC and SSD. The accuracy of discriminating pathology pattern was 81.3%, 92.2%, 71.9% and 71.9%, respectively. There was a statistical difference between VC and SSD. MPR could determine accurately the circumference of colorectal carcinoma, Raysum could determine the length of lesion more precisely than SSD, VC was helpful in discriminating pathology patterns. CONCLUSION: MPR, VC, SSD and Raysum have advantage and disadvantage in detection of colorectal carcinoma, use of these methods in combination can disclose the lesion more accurately. (+info)