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Biomedical subjects

W Jaschke

Publications and source records attributed to W Jaschke.

At least 19 recordsLinked to original sources
PubMed2000

Virtual computed tomography colonoscopy: artifacts, image quality and radiation dose load in a cadaver study.

The purpose of our study was to evaluate the interdependency of spatial resolution, image reconstruction artifacts, and radiation doses in virtual CT colonoscopy by comparing various CT scanning protocols. A pig's colon with several artificial polypoid lesions was imaged after air insufflation with helical CT scanning using 1-, 3-, and 5-mm collimation, and pitch values varying from 1.0 to 3.0. Virtual endoscopic images and "fly through" sequences were calculated on a Sun Sparc 20 workstation (Navigator Software, GE Medical Systems, Milwaukee, Wis.). Several reconstruction artifacts as well as overall image quality were evaluated by three independent reviewers. In addition, radiation doses for the different CT protocols were measured as multiple-scan average dose using a 10-cm ion chamber and a standard Plexiglass body phantom. Generally, image quality and reconstruction artifacts were less affected by pitch values than by beam collimation. Thus, narrow beam collimation at higher pitch values (e. g. 3 mm/2.0) seems to be a reasonable compromise between quality of virtual endoscopic images and radiation dose load.

Animals↗
PubMed2000

Head and neck tumors: fractionated frameless stereotactic interstitial brachytherapy-initial experience.

The authors used a frameless stereotactic navigation system, the Vogele-Bale-Hohner head holder, and a targeting device to reproducibly position brachytherapy needles for fractionated interstitial brachytherapy in 12 patients with inoperable cancers of the head and neck. In all cases, deviations of the needle relative to the planned position were within 1-15 mm depending on the location of the tumor.

Brachytherapy↗
PubMed2000

Computer-assisted neurosurgery by using a noninvasive vacuum-affixed dental cast that acts as a reference base: another step toward a unified approach in the treatment of brain tumors.

OBJECT: The purpose of the study was to evaluate the use of the Vogele-Bale-Hohner (VBH) mouthpiece, which is attached to the patient's upper jaw by negative pressure, for patient-image registration and for tracking the patient's head during image-guided neurosurgery. METHODS: A dynamic reference frame (DRF) is reproducibly mounted on the mouthpiece. Reference points, optimally distributed and attached to the mouthpiece, are used for registration in the patient's absence on the day before surgery. In the operating room, the mouthpiece and DRF are precisely repositioned using a vacuum, and the patient's anatomical structures are automatically registered to corresponding ones on the image. Experimental studies and clinical experiences in 10 patients confirmed repeated (rigid body) localization accuracy in the range of 0 to 2 mm, throughout the entire surgery despite movements by the patient. CONCLUSIONS: Because of its noninvasive, rigid, reliable, and reproducible connection to the patient's head, the VBH vacuum-affixed mouthpiece grants the registration device an accuracy comparable to invasive fiducial markers.

Adult↗
PubMed1999

Sophisticated hospital information system/radiology information system/picture archiving and communications system (PACS) integration in a large-scale traumatology PACS.

Picture archiving and communications system (PACS) in the context of an outpatient trauma care center asks for a high level of interaction between information systems to guarantee rapid image acquisition and distribution to the surgeon. During installation of the Innsbruck PACS, special aspects of traumatology had to be realized, such as imaging of unconscious patients without identification, and transferred to the electronic environment. Even with up-to-date PACS hardware and software, special solutions had to be developed in-house to tailor the PACS/hospital information system (HIS)/radiology information system (RIS) interface to the needs of radiologic and clinical users. An ongoing workflow evaluation is needed to realize the needs of radiologists and clinicians. These needs have to be realized within a commercially available PACS, whereby full integration of information systems may sometimes only be achieved by special in-house solutions.

Ambulatory Care Facilities↗
PubMed1999

Comparative reject analysis in conventional film-screen and digital storage phosphor radiography.

The aim of this study was comparative analysis of rejected radiographs in conventional and digital radiology under the aspects number of rejected images and reasons for rejection. During 2 months waste films of conventional radiography were collected; in digital radiography each image-delete command at the postprocessing workstation was documented. Rejected images were analysed and assigned to four categories. The overall reject rate was 27.6% in the conventional and 2.3% in the digital department. Whereas in the conventional department the main reason for rejection was "exposure" and "others" (i.e. problems related to film handling), the main reason in the digital environment was "positioning". The high exposure tolerance of digital systems markedly reduces the amount of faulty images. This is not only economically rewarding, but may also reduce unnecessary X-ray exposure of patients due to image retake.

Humans↗
PubMed1998

Sonographic appearance of an appendix carcinoma.

Malignant appendix tumours are rare entities. Especially adenocarcinomas, which only appear in about 10% of appendix tumours, are very seldom. Preoperative diagnosis is very difficult due to a lack of typical clinical signs and a clinical appearance mimicking perforated appendicitis. Nevertheless, sonography is able to show indirect signs and therefore it can provide the surgeon with more information for a better operative treatment.

Adenocarcinoma↗
PubMed1998

[Doppler ultrasound determination of average blood flow velocity and flow volume in transjugular intrahepatic portosystemic shunt (TIPS)].

AIM: To determine if duplex sonographic measured Time Average Motion (TAM) is an effective parameter for screening examination in routine follow-up after TIPS implantation. PATIENTS AND METHODS: 35 patients underwent duplex sonographic examination by a 3.5 MHz transducer with a follow-up for 12.4 months. RESULTS: A reduction of TAM about 60% from baseline proved with a sensitivity of 90% and a specificity of 93.7% the presence of a hemodynamic relevant stenosis, which was confirmed with angiography. We failed to establish a threshold which pointed out with acceptable accuracy the presence of shunt dysfunction. CONCLUSION: TAM is a good parameter in colour-duplex sonography which permits an objective view of TIPS-function. Angiography should be performed only in patients with suspect duplex-results or clinical worsening. A secondary sign of shunt dysfunction is increasing ascites.

Adult↗
PubMed1998

[Ruptures of the medial gastrocnemius muscle: diagnosis with high resolution ultrasound].

AIM: Evaluation of high resolution ultrasound to diagnose rupture of the medial head of gastrocnemius muscle in patients with uncharacteristic calf pain. METHOD: 66 patients with clinically unclear calf pain were examined in a prospective study. RESULTS: Out of 66 patients, 51 showed sonographic criteria of a partial rupture of the medial gastrocnemius head. 47 ruptures were located in musculotendineus transition zone. CONCLUSION: High resolution sonography detect minimal lesions of the medial gastrocnemius muscle in patients with clinically uncharacteristic calf pain.

Adult↗
PubMed1998

[ACOnet (Austrian Academic Computer Network) as data carrier for teleradiologic consultations].

PURPOSE: To assess the feasibility of image transfer for teleradiologic consultations using the Austrian Academic Computer Network (ACOnet). The ACOnet corresponds between the main universities to a MAN (Metropolitan Area Network) with a transfer rate of 4 Mbps. Its use is free of charge for university institutions. MATERIALS AND METHODS: 1740 test image data sets and 620 image data sets for teleradiological consultations were exchanged without annotations between the Departments of Diagnostic Radiology of the universities of Innsbruck and Graz, using the ACOnet. RESULTS: Data transmission was reliable and fast with an average transfer capacity of 170.2 kBytes/s (94-341 kBytes/s). There were no major problems with image transfer during the test phase. CONCLUSION: Due to its high transfer capacity, the ACOnet is considered a reasonable alternative to the ISDN service.

Austria↗
PubMed1998

[First experiences with the trauma radiologic PACS project at the University of Innsbruck Department of Radiology].

Radiography in an emergency setting is a demanding task, in technical as well as in logistical terms. Rapid acquisition of high quality radiographs under difficult conditions, for example severely injured patients with multi-organ trauma is important. All image data and radiological reports must be transmitted to the trauma surgeon as soon as possible. To meet these needs with the promising means of modern X-ray technology, we decided to implement a completely digital X-ray division inside the new outpatient trauma department. In the setting of an outpatient emergency department digital radiography and PACS cannot be realised without problems. We present our first experience with the installation and 10 month filmless routine in the X-ray division for traumatology outpatients at the university of Innsbruck department of radiology.

Emergencies↗
PubMed1998

The Austrian Academic Computer Network and its usefulness for teleradiology.

To study the value of the Austrian Academic Computer Network (ACOnet) for teleradiology, 1740 test image data-sets and 620 image data-sets were exchanged between the departments of diagnostic radiology of the Universities of Innsbruck and Graz using the ACOnet service. Data transmission was reliable and fast with an average transfer capacity of 170 kByte/s (range 94-341). During the test phase, no major problems with image transfer occurred. Assuming that problems like security of patient data-sets, data compression and data verification can be solved, the ACOnet service would be a useful additional tool for telemedicine applications throughout Austria and eastern Europe.

Austria↗
PubMed1997

Virtual computed tomography gastroscopy: a new technique.

BACKGROUND AND STUDY AIMS: The aim of the present study was to establish a suitable method for virtual computed tomography (CT) gastroscopy. PATIENTS AND METHODS: Three-millimeter helical CT scans of a pig stomach were obtained after air insufflation and instillation of diluted diatrizoic acid (Gastrografin), and with double contrast. In addition, three patients with gastric tumors were studied after ingestion of an effervescent agent (Duplotrast, 6 g) and intravenous injection of hyoscine butylbromide (Buscopan, 1 ml). Virtual endoscopy images were computed on a Sun Sparc 20 workstation (128 megabytes of random access memory, four gigabytes of hard disk space), using dedicated software (Navigator, General Electric Medical System Company). The endoscopy sequences were compared with real endoscopic examinations and with anatomical specimens. RESULTS: In the cadaver studies, the best results were obtained with plain air insufflation, whereas virtual CT gastroscopy with diluted contrast and with double contrast showed artifacts simulating polyps, erosions, and flat ulcers. Patient studies showed good correlation with the fiberoptic endoscopy findings, although large amounts of retained gastric fluid substantially reduced the quality of the surface reconstruction. CONCLUSION: These preliminary results show that virtual CT gastroscopy is able to provide insights into the upper gastrointestinal tract similar to those of fiberoptic endoscopy. However, due to the limited spatial resolution of the CT protocol used, as well as inherent image artifacts associated with the Navigator program's reconstruction algorithm, the form of virtual CT gastroscopy studied was not capable of competing with the imaging quality provided by fiberoptic gastroscopy.

Animals↗
PubMed1997

Adrenal-sparing laparoscopic surgery for aldosterone-producing adenoma.

We herein present the first case in the literature of enucleation of an aldosterone-producing adenoma by laparoscopy. The indication for adrenal-sparing surgery was bilateral adrenal adenoma. The operation turned out to be easier than laparoscopic adrenalectomy. The postoperative course was uneventful, and the patient was cured; split adrenal function tests showed normal function of both adrenal glands.

Adenoma↗
PubMed1997

Fibromuscular dysplasia of the internal carotid artery in a child with alpha-1-antitrypsin deficiency.

Fibromuscular dysplasia (FMD) is a non-inflammatory segmental arteriopathy of unknown origin. Most often the renal arteries are affected, however, also mesenteric, lumbar, vertebral, or carotid arteries may be involved. FMD has frequently been reported as a cause of stroke in adults, but very rarely in children. We report the case of an 11-year-old boy who presented with an ischaemic infarction in the anterior part of the territory of the left middle cerebral artery. Angiography demonstrated a 'string of beads' lesion suggestive of FMD causing occlusion at the origin of the middle artery. Laboratory analyses revealed the protease inhibitor (Pi) phenotype SZ (PiSZ) of alpha-1-antitrypsin deficiency as well as decreased antioxidants and signs of enhanced lipid peroxidation. Such an imbalance may be associated with diminished resistance to oxidation, possibly causing direct cellular and tissue injury. Whether alpha-1-antitrypsin deficiency and an impaired status of antioxidants, as seen in our patient, might play a role in the pathogenesis of FMD is presently unclear.

Antioxidants↗