Biomedical subjects

Maarten Thomeer

Publications and source records attributed to Maarten Thomeer.

4 recordsLinked to original sources

PubMed2005

Life-threatening hemoptysis caused by chronic idiopathic pulmonary hilar fibrosis with unilateral pulmonary vein occlusion.

We present the case of a patient who has a life-threatening hemoptysis caused by occlusion of the right pulmonary vein owing to external compression by excessive fibrous tissue. Because the patient's lung was essentially nonfunctional and hemoptysis persisted, we performed a pneumonectomy on her. Pathological analysis of the lung showed severe hypertensive changes in the arterial and venous microvasculature of the lung. Parenchymal-pleural to intercostal systemic venous connections had developed, facilitating venous drainage of the lung circulation. Upon review of the patient's history and the pathological and radiological evidence, we concluded that the pathological changes were caused by a variant of mediastinal fibrosis termed chronic idiopathic pulmonary hilar fibrosis, of which only a few cases have been described in the literature. A detailed case history and review of the literature are presented.

Collateral Circulation↗

PubMed2002

Dry preparation for virtual CT colonography with fecal tagging using water-soluble contrast medium: initial results.

The purpose of this study was to evaluate the feasibility of a dry bowel preparation, i.e. without laxative fluids, for virtual CT colonography (VCTC), and its impact on patient acceptance compared with conventional colonoscopy (CC). A randomly chosen patient population scheduled for CC ( n=11) was first submitted to VCTC after a dry preparation, consisting of low-residue meals combined with a small amount of a iodinated water-soluble contrast medium during each meal 3 days before VCTC. In different colon segments and between different persons, the degree of tagging in VCTC was evaluated and graded. Patient acceptance and future preference were assessed for both preparations as well as for both investigations. The mixing of the contrast with the intestinal content results in contrast impregnated stool, the tagged feces. The degree of fecal tagging was good in the majority of the patients and the colonic segments, especially in the descending colon and sigmoid. Furthermore, patient acceptance and preference were clearly in favour of VCTC compared with CC merely because of the non-invasiveness of the dry preparation. Dry bowel preparation and VCTC is a promising approach towards a patient-friendly colon cancer-screening setup.

Adult↗

PubMed2001

Computer-aided diagnosis in virtual colonography via combination of surface normal and sphere fitting methods.

The success of CT colonography (CTC) depends on appropriate tools for quick and accurate diagnostic reading. Current advancements in computer technology have the potential to bring such tools even to personal computer level. In this paper a technique for computed-aided diagnosis (CAD) using CT colonography is described. The method uses a combination of surface normal and sphere fitting methods to label positions in the volume data, which have a strong likelihood of being polyps, and presents them in a user-friendly way. The method was tested on a study group of 18 patients and the detection rate for polyps of 10 mm or larger was 100%, comparable to that of human readers. The price paid for a high detection rate was a large number of approximately eight false-positive findings per case. Our results show that CAD is feasible, and if the number of false positives is further reduced, then this method can be useful for clinical screenings.

Algorithms↗

PubMedDate not supplied

Stool tagging applied in thin-slice multidetector computed tomography colonography.

OBJECTIVE: To compare thin-slice multidetector computed tomography colonography (CTC) that uses stool tagging with colonoscopy. METHOD: One hundred fifty patients scheduled for colonoscopy underwent high-resolution CTC. An iodinated contrast agent was added to the preparation to tag the residual colonic fluid and stool. The effect of fluid tagging was assessed first. Sensitivity and specificity were calculated for two independent readers. In addition, values were recalculated separately for the first and last 75 patients. RESULTS: Tagging was optimal in 95.3% of the cases, and reader confidence was high. Sensitivities were 64.1%-66.7% (for the 2 readers) for 5- to 9-mm polyps and 91.7% for larger polyps. The overall specificity was 94.2% and 95%. Sensitivity improved during the study for both 5- to 9-mm polyps (from 54.2%-58.3% to 80%) and polyps larger than 9 mm (from 50% to 100%). Specificity changed nonuniformly. CONCLUSION: The combination of fluid tagging and high-resolution scanning in CTC showed high sensitivity and specificity, especially concerning sensitivity for polyps of 10 mm and larger.

Colon↗