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Biomedical subjects

J Hug

Publications and source records attributed to J Hug.

At least 19 recordsLinked to original sources
PubMed2004

Detailed anatomy of the abdomen and pelvis of the visible human female.

We report on a virtual anatomical preparation of the abdomen and pelvis of the Visible Human Female (VHF) for laparoscopic surgery training. The detailed cross-sectional image data set from the U.S. National Library of Medicine was used as the basis to build an exemplary model of the female abdomen and pelvis. Segmentation software was developed to delineate organ outlines and more than 300 structures of interest, including organs, blood vessels, bones, muscles, and ligaments, have been segmented and three-dimensionally reconstructed. Analyzing the normal anatomy we found several variations and pathologies of the VHF, such as missing muscles (gemellus superior, psoas minor), additional veins as well as spondylophytes (vertebral column, pubic bone), and colon diverticula. The complete data set may be viewed on the home page of the project (http://www.vision.ee.ethz.ch/projects/Lasso/start.html).

Abdomen↗
PubMed2000

[Long-term outcome after coronary emergency intervention].

BACKGROUND AND OBJECTIVE: Coronary angioplasty (CAG) has become an acceptable method of treating an acute coronary syndrome (myocardial infarction [MI] or unstable angina [UA]). It was the aim of this study to determine whether the results of such emergency treatment differed from those after elective CAG. PATIENTS AND METHODS: Results of emergency CAG in 581 patients (aged 60 +/- 11 years; 77% males) admitted to the authors' hospital between July 1994 and December 1996 were compared with those of elective CAG in 2,460 patients (aged 61 +/- 10, admitted during the same period. Follow-up information was obtained after 22.4 +/- 11 months in 93.2% of the patients by examination, written answers to annual questionnaires, data being collected on survival, repeat cardia catheterizations, other interventions, aorto-coronary bypass, occurrence of myocardial infarction, the patients' general state and drugs received. RESULTS: 19 of 517 patients (3.7%) of the group who had undergone elective CAG had died during the follow-up period, compared with 107 of 2436 of the emergency cohort (4.4%; not significant). There were also no significant differences regarding repeat cardiac catheterization, interventions, coronary bypass or re-admission. The proportion of subsequent emergency CAG among all CAGs was 16.8% in the emergency cohort, 8.8% after elective angiography (p < 0.001). CONCLUSION: Coronary angiography performed in patients with an acute coronary syndrome has no prognostic significance regarding mortality and morbidity after the acute phase of the disease.

Aged↗
PubMed2000

Coronary arterial stents: safety and artifacts during MR imaging.

PURPOSE: To investigate the safety and imaging artifacts with different coronary arterial stents and magnetic resonance (MR) imaging sequences. MATERIALS AND METHODS: The heating, artifacts, and ferromagnetism with different stents were studied with a 1.5-T MR tomograph with ultrafast gradients by using turbo spin-echo, turbo gradient-echo, and echo-planar imaging sequences. Nineteen stents, which were 8-25 mm in length and 3.0-4.5 mm in diameter, were evaluated. Stent deviation induced by the magnetic field and during MR imaging, migration, and heating caused by the radio-frequency pulses were examined. The size of imaging artifacts was measured with all the stents under standardized conditions and with six stents after their implantation into the coronary arteries of freshly explanted pig hearts. RESULTS: All except two types of stents showed minimal ferromagnetism. No device migration or heating was induced. Turbo spin-echo images had minimal artifacts; larger artifacts were seen on the turbo gradient-echo and echo-planar images. With ultrafast gradients, the artifacts on the echo-planar images were substantially reduced. CONCLUSION: The studied coronary stents were not influenced by heating or motion during 1.5-T MR imaging. Artifact size differed according to the type and size of the stent and the MR imaging sequence used. Thus, patients with these stents can be safely examined.

Angioplasty, Balloon, Coronary↗
PubMed1999

Noninvasive determination of coronary blood flow velocity with magnetic resonance imaging: comparison of breath-hold and navigator techniques with intravascular ultrasound.

The aim of this study was to evaluate two different magnetic resonance (MR) techniques for the noninvasive assessment of intracoronary blood flow. Coronary blood flow velocities were measured invasively in 26 angiographically normal segments of 12 patients. Noninvasive measurements were performed in identical segments with two MR techniques using a 1.5 T MR tomograph (ACS NT, Philips). A single breath-hold technique (temporal resolution: 140 msec) and a similar non-breath-hold technique with prospective navigator correction and improved temporal resolution (45 msec) were used. Maximal coronary flow velocities determined by MR correlated closely with invasive measurements (breath-hold: r = 0.70; navigator: r = 0.86); however, a significant underestimation of the MR measurements was found (slope = 0.33 and 0.37). The relative difference from the invasive method was lower for the navigator technique compared with the breath-hold technique (P<0.02). Both MR techniques allow the determination of coronary blood flow velocities. The higher temporal resolution and shorter acquisition window of navigator-corrected non-breath-hold techniques lead to increased accuracy. This approach is a further step toward the diagnostic use of MR flow measurements in coronary artery disease.

Aged↗
PubMed1999

Optimization of realtime adaptive navigator correction for 3D magnetic resonance coronary angiography.

Breathing motion artifacts reduce the quality of MR coronary artery images. Real-time adaptive navigator correction with different correction factors (0%, 30%, 60%, 80% of diaphragmatic displacement) was used to correct for respiratory motion in 3D coronary artery imaging. Significant improvements of image quality were achieved by adaptive motion correction in comparison with conventional navigator gating. A close correlation between the correction factor, which yielded optimal image quality, and cardiac displacement relative to diaphragmatic displacement was found. The quality of coronary artery imaging can be improved using real-time adaptive navigator correction. Correction factors have to be adjusted for each segment of the coronary arteries and for each patient. Magn Reson Med 42:408-411, 1999.

Adult↗
PubMed1999

Virtual reality based surgery simulation for endoscopic gynaecology.

Virtual reality (VR) based surgical simulator systems offer very elegant possibilities to both enrich and enhance traditional education in endoscopic surgery. However, while a wide range of VR simulator systems have been proposed and realized in the past few years, most of these systems are far from able to provide a reasonably realistic surgical environment. We explore the basic approaches to the current limits of realism and ultimately seek to extend these based on our description and analysis of the most important components of a VR-based endoscopic simulator. The feasibility of the proposed techniques is demonstrated on a first modular prototype system implementing the basic algorithms for VR-training in gynaecologic laparoscopy.

Computer Graphics↗
PubMed1998

Ketamine blocks a conditioned taste aversion (CTA) in neonatal rats.

These experiments explored the effects of glutamate, N-methyl-D-aspartate (NMDA) receptor blockade on the formation, retention, and expression of conditioned taste aversion (CTA) in young rats. Previous data from our laboratory suggested that ketamine administration potentiates a CTA in E18 rat fetuses. The current studies investigated this phenomenon in neonates. High-pressure liquid chromatography (HPLC) methods were used to determine the amount of ketamine that must be injected intraperitoneally (i.p.) to achieve brain ketamine levels in neonates comparable to those found in the fetuses from our previous experiments. Then, on their day of birth, Sprague-Dawley rat pups received injections of either 0.1, 10, or 70 mg/kg of ketamine HCI, i.p. or a Sal control injection. One-half hour later, pups were injected orally with either Saccharin (Sac; 10 microL of 0.3%) or water followed by an injection of either lithium chloride (LiCl; 81 mg/kg) or Sal (i.p.). The CTA was evaluated in two different tests. Two weeks after conditioning, the dam was anesthetized and the frequency with which pups attached to Sac-painted nipples versus nipples painted with water was measured (i.e., the nipple taste test, NTT). Controls for state-dependent learning were run in which 10 mg/kg of ketamine or saline (Sal) was administered before both taste aversion conditioning and the NTT. After weaning, the CTA was also evaluated by measuring the amount of Sac (0.3%) or water consumed during a two-bottle test. Neonates that received Sal control injections before the Sac + LiCl pairing acquired CTAs and avoided Sac-painted nipples. However, the pups injected with ketamine on the conditioning day only (P0) did not avoid Sac-painted nipples (as compared to controls). Pups that had ketamine both at the time of CTA training and testing, or just before the NTT, also failed to avoid Sac-painted nipples. Ketamine's acute effects apparently influenced the outcome of the NTT of state-dependent control subjects. Rat pups that received the highest doses of ketamine (10 or 70 mg/kg) and tasted Sac on P0 later failed to show a neophobia for Sac-painted nipples. Whereas, rat pups that received the high dose of ketamine and water on P0, later exhibited a neophobic response. These data suggest that ketamine did not impair the animal's ability to taste Sac. These data reflecting a ketamine-induced blockade of neonatal CTAs may be contrasted with our previous findings in which ketamine potentiated fetal CTAs. However, they are in consonance with data from adult rats suggesting that ketamine can cause an amnesia for CTAs. NMDA receptor blockade may shape memory formation in a manner that is dependent on the stage of brain development.

Animals↗
PubMed1998

Percutaneous closure of secundum atrial septal defect with a new self centering device ("angel wings").

OBJECTIVE: To investigate the safety, efficacy, and clinical application of a new self centering device ("angel wings") for closure of secundum atrial septal defects (ASD II) and persistent foramen ovale in all age groups. DESIGN: Multicentre, prospective, nonrandomised study. PATIENTS INCLUSION CRITERIA: defects with an occlusive diameter of < or = 20 mm and a surrounding rim of > 4 mm; body weight > 10 kg; and an indication for surgical closure of secundum atrial septal defect. Additionally, there were compassionate indications for closure in patients with persistent foramen ovale. INTERVENTIONS: Defects were closed by a transcatheter device consisting of two square frames made of superelastic nitinol wire. The frames are covered by elastic polyester fabric, which is sewn together at a central circle. All procedures, except for three interventions that were carried out under sedation, were performed under general anaesthesia using transoesophageal echocardiography and fluoroscopy to monitor intervention. RESULTS: Closure was attempted in 75 (71%) of 105 patients. An ASD II was present in 35 children and 15 adults. A persistent foramen ovale was present in 25 adults with suspected paradoxical embolism. Transcatheter closure was unsuccessful in three children and crossover to surgery was required. Residual shunts were found in 20 patients (27%) immediately after the procedure. A transient atrioventricular third degree block occurred in three patients (4%) and the right atrial disk was not fully deployed in three. A minor shunt (< 3 mm) was present in only three (4%) of 72 patients during follow up of 1-17 months. Blood clots on the right atrial disks in two patients (one required lysis) were seen during follow up transoesophageal echocardiography. Serious complications demanding surgical removal of the device occurred in three patients. One patient had haemopericardial tamponade because of an aortic lesion. Left atrial thrombus formation due to an unfolded right atrial disk was found in a second patient and dislodgement of the left atrial disk resulted in a large residual shunt in a third. CONCLUSIONS: Percutaneous closure of a central ASD with a diameter < or = 20 mm in paediatric and adult patients is feasible and effective with this new device. It is a promising alternative to surgical closure. Modifications of the design, however, seem to be mandatory as 4% of patients developed serious complications.

Adolescent↗
PubMed1996

Incomplete aspirin desensitization in an aspirin-sensitive asthmatic.

Aspirin desensitization is a valuable treatment for aspirin-sensitive sinusitis. We present a case where long-term desensitization failed. While undergoing desensitization, our patient had prolonged severe asthmatic reactions and therefore received high intravenous doses of prednisone. We hypothesize that high steroid doses administered at the time of desensitization may have raised the threshold of intolerance to a point where the administered aspirin doses were tolerated. Consequently, symptoms of intolerance subsided during the procedure. Subsequent tapering down of the daily prednisone dose caused a re-emergence of the symptoms of intolerance, apparently due to a decrease in the intolerance threshold.

Aspirin↗
PubMed1985

[Anesthesiologic problems in unsuspected extra-adrenal pheochromocytoma].

Although surgical mortality associated with pheochromocytoma has been markedly reduced in recent years, due to improvements in medical and anesthesiologic management, surgery in patients with unsuspected pheochromocytoma is still accompanied by a high fatality rate. A 20-year-old man without history of hypertension and previously in good health is reported who presented for exploratory thoracotomy and removal of a highly vascular mediastinal tumor. Intraoperatively a pheochromocytoma was suspected. Problems associated with establishing the diagnosis as well as difficulties in treating rapid changes of sympathetic adrenergic activation and hypotension following tumor resection are discussed. Despite the comparative rarety of pheochromocytoma the anaesthesiologist should be aware of unusual clinical manifestations.

Adult↗