Henk W. Venema

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PURPOSE To investigate the sensitivity and specificity of polyp detection and the image quality of computed tomographic (CT) colonography at different radiation dose levels and to study effective doses reported in literature on CT colonography. MATERIALS AND METHODS CT colonography and colonoscopy were performed with 100 mAs in 50 consecutive patients at(More)
Results are reported of a feasibility study in which bone pixels are eliminated from computed tomographic (CT) angiographic images with a method that enables the construction of maximum intensity projection (MIP) images without interference by bone. The method proved to be successful in six patients. Two observers blinded to the bone elimination method(More)
OBJECTIVE The purpose of this study was to accurately quantify three-dimensional in vivo kinematics of all carpal bones in flexion and extension and radial and ulnar deviation. DESIGN AND METHODS The right wrists of 11 healthy volunteers were imaged by spiral CT with rotational increments of 5 degrees during ulnar-radial deviation and of five of them also(More)
The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to(More)
PURPOSE To investigate whether coronal multiplanar reconstruction (MPR) images of the petrosal bone from axial spiral computed tomographic (CT) data obtained with 0.5-mm collimation can replace direct coronal sequential CT scans obtained with 0.5- or 1.0-mm collimation. MATERIALS AND METHODS The differences in diagnostic quality between thin-section(More)
BACKGROUND AND PURPOSE Routine CT of the brain is traditionally performed with sequential CT. We assessed whether sequential CT can be replaced with thinly collimated multisection spiral CT without loss of image quality. MATERIALS AND METHODS An observer study was conducted using data from 23 patients who were scanned with both a sequential (collimation,(More)
The purpose of this study was to estimate the effective dose that is currently used in CT colonography using scan parameters that were collected for this purpose, and to investigate trends in time. PubMed was systematically searched from 1996 until January 2004 for studies investigating CT colonography. Research institutions were contacted and asked for(More)
The purpose was to evaluate low-dose CT colonography without cathartic cleansing in terms of image quality, polyp visualization and patient acceptance. Sixty-one patients scheduled for colonoscopy started a low-fiber diet, lactulose and amidotrizoic-acid for fecal tagging 2 days prior to the CT scan (standard dose, 5.8–8.2 mSv). The original raw data of 51(More)
In a feasibility study, the authors compared polyp detection and interobserver variability at computed tomographic (CT) colonography in 15 patients with doses ranging from medium to very low (12.00-0.05 mSv). At levels down to 2% of the medium dose, the mean detection of polyps 5 mm or larger remained at least 74%, while the number of false-positive results(More)
In maximum intensity projection (MIP) images of CT angiography (CTA) scans, the arteries are often obscured by bone. A bone removal method is presented that uses an additional, nonenhanced scan to create a mask of the bone by thresholding and dilation. After registration of the CTA scan and the additional scan, the bone in the CTA scan is masked. As the(More)