Search PubMed⌕ Search

Biomedical subjects

B Schwaighofer

Publications and source records attributed to B Schwaighofer.

At least 19 recordsLinked to original sources
PubMed1998

Efficacy of thrombolytic therapy in pulmonary embolism determined by MION-enhanced MRA: an experimental study in rabbits.

RATIONALE AND OBJECTIVES: This study determined whether contrast-enhanced magnetic resonance angiography could be used as a noninvasive imaging technique to determine the therapeutic effect and endpoint in thrombolysis of acute pulmonary embolism in an animal model. METHODS: New Zealand white rabbits (n = 18) were anesthetized and mechanically ventilated. Single (n = 12 emboli) or dual (n = 12 emboli in 6 animals) pulmonary emboli were created by injecting autologous thrombi through a right internal jugular venous approach. Three-dimensional time of flight (TOF) magnetic resonance angiograms were obtained after intravenous administration of 2 mg Fe of a long circulating monocrystalline iron oxide. Animals then received 5000 IU heparin and 1.3 mg recombinant tissue plasminogen activator/kg intravenously, and magnetic resonance angiography was repeated 30 minutes and 60 minutes after initiation of thrombolytic therapy. RESULTS: MION-enhanced magnetic resonance angiography accurately detected pulmonary emboli in all rabbits. Thrombolysis during the observation period was successful in 8 of the 18 animals. In animals with a single embolus, the revascularization rate was 50% (6 of 12 emboli). The rate was 33% (4 of 12 emboli) in animals with multiple emboli. Magnetic resonance angiography allowed determination of thrombus resolution or thrombus persistence. CONCLUSIONS: It was feasible to diagnose pulmonary embolism accurately in this experimental study and to monitor thrombolysis of pulmonary emboli by MION-enhanced magnetic resonance angiography.

Acute Disease↗
PubMed1993

Difficulties in examination of the origin of the vertebral artery by duplex and colour-coded Doppler sonography: anatomical considerations.

Despite progress in ultrasonographic techniques visualisation of the origin of the vertebral arteries, particularly the left, by duplex and colour Doppler imaging, still poses a problem in a significant number of patients. In anatomical and radiological studies we demonstrated an anomalous origin in 6%, the left vertebral artery originating directly from the aorta in most cases. The origin from the subclavian artery was found to be posterior in 44% and inferior in 6%. The V1 segment of the vertebral artery (from its origin to the entry into the foramen transversarium) was tortuous in 47% of cases. These anatomical variants and variations in the course of the vessel contribute to the nonvisualisation of the origin of the vertebral artery by duplex and colour Doppler imaging. With respect to tortuosities technical modifications for better visualisation are suggested and possible implications for surgery are discussed.

Aged↗
PubMed1993

[Acute renal vein thrombosis in children. Early detection with duplex and color-coded Doppler ultrasound].

Two children with clinically suspected renal vein thrombosis were evaluated by duplex Doppler sonography and colour flow imaging. Both cases presented unspecific findings with an enlarged kidney and loss of cortico-medullary delineation on gray-scale ultrasound, but an unusual flow pattern with retrograde plateau-like frequency shifts during diastole. No venous signal could be obtained. By colour flow imaging only the main renal artery and its proximal branches could be visualised with a reverberating oscillation of blood flow. In addition, partial thrombosis of inferior vena cava in one patient and iliac vein thrombosis in the other could be demonstrated. Clinical improvement during fibrinolytic therapy in one case and nephrectomy in the other case confirmed the diagnosis.

Aortic Coarctation↗
PubMed1992

[Saphenous vein bypass stenoses, early diagnosis with color coded Doppler sonography].

In a prospective study 54 patients with 62 saphenous vein arterial bypass grafts were examined by colour-coded Doppler sonography and angiography. Five cases of graft occlusion were diagnosed by colour-coded Doppler sonography and confirmed by angiography. In comparison with angiography, colour-coded Doppler sonography showed a sensitivity of 92% and a specificity of 100% in the detection of focal graft stenosis. Only two stenoses in the region of the distal anastomosis could not be detected by colour-coded Doppler sonography. In 28 cases a marked dilatation of the proximal anastomosis was found corresponding to the surgically used patch angioplasty. Within this dilated bypass segment, turbulence and flow reversal zones were demonstrated, which might be predisposing factors for graft stenosis. Colour-coded Doppler sonography can accurately detect saphenous vein arterial bypass graft stenoses and should be routinely used in postoperative screening.

Adult↗
PubMed1991

[Vascular space-occupying lesions of the carotid artery--detection with color-coded Doppler sonography. Comparison with duplex sonography and angiography].

Nine patients with a cervical tumour, diagnosed by duplex Doppler sonography were additionally evaluated by colour-coded Doppler sonography (CCDS). The duplex Doppler diagnosis of three internal carotid artery aneurysm was confirmed by CCDS in only one patient. In the remaining two cases CCDS identified a marked coiling of the internal carotid artery. Three low echogenic lesions, interpreted as cervical lymphomas by conventional Doppler sonography were identified as two internal carotid aneurysm with partial thrombosis and a carotid body tumour in the third patient by CCDS. Duplex-Doppler sonography and CCDS agreed in the diagnosis of two AV-malformations and one carotid body tumour. Angiography confirmed the CCDS-diagnosis in 7 patients. In the two patients with coiling of the ICA angiographic evaluation was not performed. Thus, CCDS was superior to duplex Doppler sonography in the evaluation of vascular lesions of the extracranial section of the carotid artery and provided additional diagnostic information.

Aneurysm↗
PubMed1991

[The patency of the external and internal carotid arteries in patients with occlusion of the common carotid: detection using color-coded Doppler sonography].

Common carotid artery occlusion is not necessarily associated with thrombosis of the ipsilateral internal carotid artery. Noninvasive imaging of the carotid bifurcation with colour-coded Doppler sonography demonstrated patency of the external and internal carotid arteries distal to a common carotid occlusion in 4 patients which could be proven surgically. Identification of internal carotid artery patency could be demonstrated by angiography in two of the patients while in the other two cases angiography was inconclusive. Thus, CCDS provided a correct diagnosis of the internal carotid patency in these patients with common carotid occlusion.

Adult↗
PubMed1991

[Varicosis orbitalis. Its demonstration by color-coded Doppler sonography and computed tomography].

Three patients with intermittent exophthalmos were studied by computed tomography (CT) and colour-coded Doppler sonography (CCDS). By CT the possible diagnosis of an orbital varix was established. CCDS, however, with the dynamic evaluation and realtime direct imaging of flow and the possibility of examination in different positions facilitated the diagnosis of this orbital vascular disorder without the need for any contrast material. This technique may prove to be a useful adjunct to computed tomography for the evaluation of suspected vascular lesions of the orbit. Surgery confirmed the diagnosis in all patients.

Color↗
PubMed1991

Color-coded Doppler sonography of vertebral arteries.

Color-coded Doppler sonography of the vertebral arteries was performed in 86 patients who had a history of vertebrobasilar disease. The origin of the artery was visualized in 87.2% on the right and 70.9% on the left side. The inter-transverse portion of the vertebral artery was visualized in 95% on the right and 97% on the left side. The atlas loop could be visualized in 88.4% on the right and 84.9% on the left side. Pathologic findings were hypoplasia (n = 4), stenosis (n = 19), dissection (n = 2), occlusion (n = 7), kinking (n = 12), cervical tumors (n = 3), and subclavian steal syndrome (n = 3). Nine postoperative patients had subclavian and vertebral artery reimplantation to the common carotid artery. The characteristic color-coded Doppler sonographic features of these findings are presented and discussed.

Angiography↗
PubMed1990

[Velocity variance function: additional information in color-coded Doppler sonography of the carotids].

A new software, called the velocity variance programme, by which flow disturbances are additionally colour-coded, was systematically applied with colour Doppler sonography in 59 patients with stenotic atheromatous lesions of different grades in the carotid bifurcation. A direct comparison with and without using this programme was made. In group 1 (n = 23) with stenosis of the internal carotid artery of more than 50% it could be demonstrated that flow disturbances were maximally in the region immediately downstream of the stenosis and complete dissipation of these effects occurred within 8-10 vessel diameters downstream. Moreover, a direct correlation between the size of the region of disturbed flow and the irregularity of the stenotic plaque surface within the stenosis could be demonstrated. Distal to the stenosis there was an inverse relationship between the extension of disturbed flow and the length of the stenosis and a direct relationship to the grade of the stenosis and the irregularity of the plaque surface. In patient group 2 (n = 36) with less than 50% diameter reduction, a local flow disturbance near the atheromatous plaque was shown in 27 patients. In eighteen of these patients the region of disturbed flow could be revealed only by using the velocity variance programme. The importance of this non-invasive in-vivo visualisation of flow disturbances in the carotid bifurcation is discussed.

Arteriosclerosis↗
PubMed1990

Is MR better than arthrography for evaluating the ligaments of the wrist? In vitro study.

The purpose of this study was to determine the relative merits of MR imaging and three-compartment digital arthrography in the assessment of carpal ligaments in vitro. We performed MR imaging and arthrography in 10 normal wrists of fresh cadavers ranging in age from 48 to 71 years, and compared the appearance of the interosseous ligaments and triangular fibrocartilage complex with findings on anatomic sections of the joints. In six of the specimens, relatively T1-weighted MR images, 800/20 (TR/TE), preceded three-compartment digital arthrography performed with standard contrast material. In the other four specimens, arthrography, using an MR solution of iodinated contrast material mixed with cupric sulfate and gelatin, was performed before MR imaging. This was done to mimic the intraarticular fluid that might be seen in an injured wrist. MR allowed accurate assessment of the triangular fibrocartilage complex and scapholunate ligament in eight of 10 cases. Consistent MR visualization of the lunotriquetral ligament was difficult. Three-compartment digital arthrography allowed accurate assessment of the triangular fibrocartilage complex and scapholunate and lunotriquetral ligaments in all 10 cases. We concluded that MR is useful but inferior to arthrography in the evaluation of interosseous ligaments and the triangular fibrocartilage complex.

Aged↗
PubMed1990

Jogging causes acute changes in the knee joint: an MR study in normal volunteers.

As MR imaging allows evaluation of soft-tissue structures not previously possible with imaging techniques, we undertook a preliminary study to evaluate the effects of a popular form of exercise (jogging) on the knee. The specific question prompting our investigation was, does repetitive impulse loading produced by jogging cause acute structural changes within the knee that are visible by MR imaging? The knees of 10 healthy subjects were examined on a 1.5-T MR system before and immediately after 30 min of continuous jogging. The same extremity was examined each time, and the imaging sequences and photographic technique (meniscal windows) were identical for both examinations. Effusions developed in five of 10 subjects after exercise. In addition, five of 10 subjects had subtle increased signal intensity within their menisci. These results suggest that jogging frequently leads to acute changes in the knee that are visible on MR imaging. The significance of these changes is unknown.

Acute Disease↗
PubMed1990

Renal osteodystrophy. Radiological diagnosis compared with a new radioimmunoassay method of parathyroid hormone.

The parathyroid hormone concentration in the blood measured by the 'two-site radioimmunoassay', which is specific for the biologically active parathyroid molecule (parathyrine), was compared with the radiological manifestations of secondary hyperparathyroidism (HPT) on magnification radiographs of the phalanges in patients undergoing maintenance hemodialysis and in patients with renal allografts. Sensitivity of radiology for the diagnosis of HPT proved to be high (88%), whereas specificity was low (30%). Statistical analysis showed that there was a good correlation between the parathyrine levels and the intensity of radiological changes in the phalanges in patients with renal allografts (coefficient of Krueger-Spearman = 0.65). In patients undergoing hemodialysis the correlation between laboratory parameters and radiological changes was poor.

Adult↗
PubMed1990

[Flow reversal in the carotid bifurcation. Detection using color-coded Doppler sonography].

Pulsatile blood flow within the normal carotid sinus involves at least two distinct components. Beside the laminar antegrade flow, there is a boundary layer separation zone in the posterolateral aspect with transient flow reversal. This flow reversal is well known from in vitro studies. It is now possible to document these flow velocity components using color-coded Doppler sonography. It is hypothesized that if flow separation is detected, this is indicative of a normal condition of the carotid bifurcation. When atherosclerosis develops, it involves preferentially the posterolateral bulb region, obliterating the normal configuration of the sinus with consequent loss of the flow separation. Therefore, loss of flow reversal should be indicative of atherosclerosis. We have studied this flow pattern retrospectively in 156 patients (312 arteries). In 4 patients no flow reversal could be detected although no atheromatous lesions could be found at the bifurcation, but in these cases there was no bulb formation in the common carotid artery or in the internal carotid artery. On the other hand, flow reversal was demonstrable in several pathological conditions within the carotid bifurcation. These included plaque formation after the bifurcation in 7 patients, internal carotid artery occlusion at the origin in 12, common carotid artery occlusion despite a patent bifurcation in 4, and marked dilatation of the lumen forming a pseudobulb following disocclusion of the carotid artery in 11 patients.

Blood Flow Velocity↗
PubMed1990

[Color-coded Doppler sonography of the vertebral arteries].

Color-coded Doppler sonography of the vertebral arteries was performed in 86 patients with a history of vertebrobasilar disease. The origin of the artery was visualized in 87.2% on the right and 70.9% on the left side. The interforamen portion of the vertebral artery was visualized in 95% on the right and 97% on the left side. The atlas loop could be visualized in 88.4% on the right and 84.9% on the left side. Pathologic findings were hypoplasia (n = 4), stenosis (n = 19), dissection (n = 2), occlusion (n = 7), kinking (n = 12), and subclavian steal syndrome (n = 3). Nine postoperative patients had subclavian and vertebral artery reimplantation into the common carotid artery. The characteristic color-coded Doppler sonographic features of these findings are presented and discussed.

Arterial Occlusive Diseases↗
PubMed1990

[The diagnostic value of scintigraphy and x-rays in unclear arthralgias of the hands].

33 patients presenting with arthralgia of wrists and finger joints were examined by radionuclide imaging and radiography. In 22 patients clinical symptoms turned out to be caused by inflammation, 11 patients suffered from degenerative joint disorder. Radionuclide imaging proved once more to be nonspecific albeit very sensitive; plain film radiography exhibited good specificity. The combination of both methods resulted in an increase in accuracy as compared to scintiphotography alone (0.88 vs. 0.79). Radionuclide imaging and radiography should therefore always be done and interpreted simultaneously. Radionuclide imaging is mandatory to confirm or to rule out inflammatory joint disorder in case of an inconclusive x-ray (absence of erosions or degenerative changes). A negative radionuclide study rules out inflammation, even when juxta-articular demineralisation is suspected on the x-ray.

Adult↗
PubMed1989

Esophageal tracheal combitube (ETC) for emergency intubation: anatomical evaluation of ETC placement by radiography.

The esophageal tracheal combitube (ETC) is designed for emergency intubation. The ETC is inserted blindly allowing ventilation after either esophageal or endotracheal placement. A special pharyngeal balloon serves to seal the upper airways. In 10 cardiac arrest patients, emergency intubation with the ETC was performed. Blood gas analyses showed adequate ventilation. Radiography proved correct placement of the proximal and distal balloons in accordance with design theory. Hyperinflation experiments documented expansion of the proximal balloon into the oral cavity rather than towards the epiglottis.

Emergencies↗