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Biomedical subjects

Peter Vock

Publications and source records attributed to Peter Vock.

44 records · Page 3Linked to original sources
PubMed2002

Is ileal orthotopic bladder substitution with an afferent tubular segment detrimental to the upper urinary tract in the long term?

PURPOSE: We determine long-term morphological changes of the upper urinary tract following ileal orthotopic bladder substitution with an afferent tubular segment without a flap-valve type antireflux procedure. MATERIALS AND METHODS: A consecutive series of long-term survivors (5 years or greater) following ileal orthotopic bladder substitution underwent regular radiological followup with excretory urography. Preoperative and postoperative renal size, parenchymal thickness, pelvicaliceal dilatation and upper urinary tract obstruction were assessed by 2 radiologists. RESULTS: A total of 76 patients with a median followup of 84 months (range 60 to 155) were evaluable. Four patients (2.6%) underwent unilateral nephroureterectomy during followup. Of the remaining 148 renoureteral units 141 (95%) revealed no significant changes in size or parenchymal thickness during followup. Renal size decreased in 6 (4%) and parenchymal thickness in 7 (5%) renoureteral units, 5 of which already had renal pathologies (dilatation, obstruction or hypoplastic kidney) preoperatively. De novo shrinkage of the parenchyma of a preoperatively normal kidney was observed in 2 (1%) renoureteral units associated with stenosis of the ureteroileal anastomosis. Of the 148 renoureteral units 14 (9%) presented with nonobstructive dilatation and 4 (3%) with complete obstruction. Preoperatively average serum creatinine level +/- SD was 98 +/- 19 micromol./l. and 10 years thereafter it was 83 +/- 27 micromol./l. CONCLUSIONS: These data suggest that unidirectional peristalsis of ureters and the afferent tubular ileal segment sufficiently protect the upper urinary tract following ileal bladder substitution up to a decade provided there are no preoperative renal pathology and no anastomotic stricture postoperatively. Additional antireflux flap-valve type implantation techniques are not required.

Aged↗
PubMed2002

High-speed documented experimental gunshot to a skull-brain model and radiologic virtual autopsy.

The authors documented and evaluated experimental gunshots to a skull-brain model with high-speed photography and subsequent radiographic examination for comparison of the morphologic findings in the model. The artificial skull was a polyurethane ball constructed in layers, with a porous diploe sandwiched between a tabula externa and a tabula interna. The brain itself was simulated with gelatin 10% at 4 degrees C, a material well known in wound ballistics. Gunshots were fired at the model from a distance of 10 m and documented with high-speed photography (up to 50 million frames/sec). Subsequently, a complete examination of the artificial skull was performed, including spiral computed tomography (with two-dimensional and three-dimensional reconstructions) and classic skull autopsy. The high-speed photographs clearly showed the dynamic development of the skull fracture system from an external perspective. The subsequent radiographic examination of the entire head volume created two-dimensional reformations in any plane and three-dimensional reconstructions of the gunshot injury of the polyurethane skull-brain model, especially the wound channel and the fracture system. Thanks to the model and high-speed photographs, the dynamic development of the morphology of a gunshot wound could be documented and studied. The data from computed tomography, using two-dimensional and three-dimensional postprocessing with a perspective view, were very similar to those from classic head autopsy, but derived in a hands-off and nondestructive manner. This examination method leads the way to radiographic digital autopsy or virtual autopsy.

Autopsy↗
PubMed2002

Multidetector CT virtual bronchoscopy to grade tracheobronchial stenosis.

OBJECTIVE: The purpose of this study was to compare the efficacy of noninvasive multidetector CT (virtual bronchoscopic images, axial CT slices, coronal reformatted images, and sagittal reformatted images) in depicting and allowing accurate grading of tracheobronchial stenosis with that of flexible bronchoscopy. MATERIALS AND METHODS: Multidetector CT and flexible bronchoscopy were used to examine 200 bronchial sections obtained from 20 patients (15 patients with bronchial carcinoma and five without central airways disease). Multidetector CT was performed using the following parameters: collimation, 4 x 2 mm, pitch, 1.375; and reconstruction intervals, 2 mm. Postprocessing was performed using surface rendering and multiplanar reformatted images. CT images were independently interpreted by two radiologists. The tracheobronchial stenoses revealed on flexible bronchoscopy were graded by a pulmonologist. RESULTS: Virtual bronchoscopic findings, axial CT scans, and multiplanar reformatted images were highly accurate (98% accuracy for virtual bronchoscopic images, 96% for axial slices and coronal reformatted images, and 96.5% for sagittal reformatted images) in revealing tracheobronchial stenosis. In allowing accurate grading of tracheobronchial stenosis, images from virtual bronchoscopy correlated closely (r = 0.91) with those of flexible bronchoscopy. Because use of virtual bronchoscopic images reduced the overestimation of stenosis, these images allowed better assessment of stenosis than did axial CT slices (r = 0.84) or multiplanar reformatted images (r = 0.84) alone. CONCLUSION: Multidetector CT virtual bronchoscopy is a reliable noninvasive method that allows accurate grading of tracheobronchial stenosis. However, it should be combined with the interpretation of axial CT images and multiplanar reformatted images for evaluation of surrounding structures and optimal spatial orientation.

Adult↗
PubMed2002

MR imaging pelvimetry: a useful adjunct in the treatment of women at risk for dystocia?

OBJECTIVE: The objective of this study was to test the clinical value of MR imaging for diagnosing cephalopelvic disproportion and for predicting labor outcome in women at risk for dystocia. SUBJECTS AND METHODS: Antepartum fetal sonography and maternal MR imaging pelvimetry measurements were performed at term in 38 pregnant women at risk for dystocia with a single fetus in cephalic presentation. Various methods used to diagnose cephalopelvic disproportion were evaluated in a blinded manner for their accuracy to predict both the presence of cephalopelvic disproportion and the mode of delivery (vaginal vs cesarean). RESULTS: None of the methods tested yielded both high sensitivity (15-100%) and high specificity (24-92%) for determining the presence of cephalopelvic disproportion and high levels of accuracy for predicting labor outcome (overall predictability, 50-74%). CONCLUSION: To achieve increased reliability of MR imaging pelvimetry in the diagnosis and treatment of dystocia and in predicting labor outcome, new methods assessing fetal-pelvic compatibility, including measurements of the pelvic outlet and the shape and configuration of the pelvis, need to be established and prospectively tested before firm recommendations for clinical use can be made.

Adult↗
PubMed2002

Charred body: virtual autopsy with multi-slice computed tomography and magnetic resonance imaging.

The correct examination of a charred body is a forensic challenge. Examination, interpretation, and conclusion in respect to identification, vital reactions, toxicological analysis, and determining cause and manner of death are all more difficult than without burns. To evaluate what can be seen in the case of a charred body, we made an examination with the new radiological modalities of cross-section techniques, via multi-slice Computed Tomography (MSCT) and Magnetic Resonance Imaging (MRI), prior to performing the classical forensic autopsy. In a charred body case of a single motor vehicle/fixed object collision with a post crash fire, the radiological methods of MSCT and MRI made it possible to document the injuries caused by burn as well as the forensic relevant vital reactions (air embolism and blood aspiration). In conclusion, we think postmortem imaging is a good forensic visualization tool with a great potential for the forensic documentation and examination of charred bodies.

Autopsy↗
PubMed2001

Complex, traumatic rupture of the thoracic aorta in a child: diagnostic findings and delayed surgery.

We report the unusual case of a 4-year-old girl with traumatic aortic rupture. A conventional chest X-ray showed an enlarged mediastinum. Spiral CT and transthoracic echocardiography demonstrated a mediastinal hematoma, bilateral pleural effusion, and a rupture of the aortic arch. Semi-elective surgery, 4 days after the accident, confirmed rupture of the aortic arch with dislocation of the left carotid artery and the Ductus of Botalli. The vessels were subsequently repaired without complication. After a follow-up of 10 months, the child has fully recovered.

Accidents, Traffic↗
PubMedDate not supplied

VIRTOPSY: minimally invasive, imaging-guided virtual autopsy.

Invasive "body-opening" autopsy represents the traditional means of postmortem investigation in humans. However, modern cross-sectional imaging techniques can supplement and may even partially replace traditional autopsy. Computed tomography (CT) is the imaging modality of choice for two- and three-dimensional documentation and analysis of autopsy findings including fracture systems, pathologic gas collections (eg, air embolism, subcutaneous emphysema after trauma, hyperbaric trauma, decomposition effects), and gross tissue injury. Various postprocessing techniques can provide strong forensic evidence for use in legal proceedings. Magnetic resonance (MR) imaging has had a greater impact in demonstrating soft-tissue injury, organ trauma, and nontraumatic conditions. However, the differences in morphologic features and signal intensity characteristics seen at antemortem versus postmortem MR imaging have not yet been studied systematically. The documentation and analysis of postmortem findings with CT and MR imaging and postprocessing techniques ("virtopsy") is investigator independent, objective, and noninvasive and will lead to qualitative improvements in forensic pathologic investigation. Future applications of this approach include the assessment of morbidity and mortality in the general population and, perhaps, routine screening of bodies prior to burial.

Autopsy↗