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Biomedical subjects

H Schreyer

Publications and source records attributed to H Schreyer.

At least 19 recordsLinked to original sources
PubMed2002

[Pelvic artery embolization in gynecological bleeding].

The most common reasons for gynecological bleeding are pregnancy-related disorders, fibroids of the uterus, and gynecological malignancies. Transarterial embolization is an effective treatment modality for gynecological bleeding regardless of its etiology. Depending on the underlying disease, a different technique of embolization is applied. In postpartal bleeding a temporary effect of embolization is desired, therefore gelatin sponge is used as embolizing agent. In fibroids and malignant tumors the effect should permanent, therefore PVA particles are used. Regardless the etiology, the technical and clinical success of transarterial embolization is at least 90 %. In nearly every patient a post-embolization syndrome can be observed, represented by local pain and fever. This post-embolization syndrome usually does not last longer than 3 days. If embolization is performed with meticulous attention to angiographic technique and handling of embolic material, ischemic damage of adjacent organs is rarely observed. Transarterial embolization should be an integrative modality in the treatment of gynecological bleeding.

Angiography↗
PubMed2000

[Current status of diagnostic imaging of focal nodular hyperplasia of the liver].

Ranging behind hemangiomas, focal nodular hyperplasias (FNH) are the second most common benign solid liver lesions. Women between the age of 20 and 50 years are predominantly affected. In rare cases FNH may occur in children. Etiologically, an arteriovenous vascular malformation of the liver is discussed, which causes pseudotumorous growth of the surrounding liver parenchyma. Morphological features such as the presence of a radial vascular architecture and feeding arteries within a central scar are characteristic for the presence of FNH. Imaging techniques which enable the depiction of the arterial blood supply with a characteristic centrifugal filling pattern, the contrast enhancement in the early arterial phase, the absence of calcifications and of a tumour capsule and the typical enhancement of the central scar, are of particular importance. Knowledge of these features is important in order to differentiate FNH from other hypervascular focal liver lesions with tendency of scar formation, such as hepatic adenomas, giant hemangiomas, hepatocellular and fibrolamellar carcinomas, and metastases. Diagnosis and differential diagnosis of FNH will be enabled by a combined modality approach consisting of (Doppler) sonography and triphasic CT. To confirm the diagnosis of FNH, dynamic MRI is advisable. Because of the invasiveness of angiography as well as the limited sensitivity and spatial resolution of the various scintigraphic methods, these modalities no longer play a role in the diagnostic work-up of FNH. Lesions lacking typical features diagnostic for FNH remain subjects for biopsy and histological examination.

Adult↗
PubMed1998

Value of echo-enhanced Doppler sonography in evaluation of transjugular intrahepatic portosystemic shunts.

OBJECTIVE: The value of echo-enhanced color and power Doppler sonography in the evaluation of transjugular intrahepatic portosystemic shunts (TIPS) was assessed and compared with that of unenhanced Doppler sonography and portal angiography. SUBJECTS AND METHODS: In a prospective randomized trial, 31 shunts in 30 patients underwent unenhanced conventional color and power Doppler sonography and portal venography including pressure measurements. The patients were allocated to either echo-enhanced conventional color Doppler sonography or echo-enhanced power Doppler sonography. For echo enhancement, a galactose-based suspension was administered IV. Shunt stenoses, if present, were quantified by percentage of stenosis and correlated with angiography, which was the gold standard. The diagnostic confidence of unenhanced and echo-enhanced Doppler sonography was assessed using a visual analog scale. RESULTS: In the diagnosis of shunt occlusion, echo-enhanced Doppler sonography yielded a sensitivity and a specificity of 100% and 100%, respectively, compared with 100% and 89%, respectively, for unenhanced Doppler sonography. Our evaluation of hemodynamically significant stenoses (portosystemic gradient > or = 15 mm Hg) found echo-enhanced Doppler sonography to be superior to unenhanced Doppler sonography (sensitivity and specificity of 82% and 83%, respectively, compared with 64% and 80%, respectively). In the detection of a shunt stenosis based on morphologic criteria only, echo-enhanced Doppler sonography yielded a sensitivity and a specificity of 78% and 100%, respectively, compared with 47% and 50%, respectively, for unenhanced Doppler sonography. Power Doppler imaging did not improve diagnostic accuracy but did increase diagnostic confidence for unenhanced Doppler sonography compared with conventional color Doppler sonography. The diagnostic confidence for sonographic evaluation of TIPS was significantly (p < .001) increased and the variability of hemodynamic measurements was markedly decreased with echo-enhanced sonography. CONCLUSION: Echo-enhanced Doppler sonography provides images of TIPS like those of angiography and allows morphologic assessment of the shunts, complementary to the essential pulsed Doppler waveform analysis that would be performed in a more guided manner. Also, echo-enhanced Doppler sonography significantly increases the sensitivity and specificity in the diagnosis of shunt dysfunction. The high diagnostic confidence and the diminished variability of spectral Doppler measurements may improve acceptance of sonographic evaluation of TIPS. Echo-enhanced Doppler sonography is safe and effective and may reduce the instances in which TIPS sonographic surveillance is nondiagnostic, in which case angiographic assessment is required.

Adult↗
PubMed1996

Distribution pattern of computed tomography findings in patients with bronchiolitis obliterans organizing pneumonia.

RATIONALE AND OBJECTIVES: The authors evaluated high-resolution computed tomography (HRCT) findings in 15 patients with biopsy-proven bronchiolitis obliterans organizing pneumonia (BOOP). Special attention was paid to lobar distribution to establish a predominant distribution pattern for this disease. SUBJECTS AND METHODS: Fifteen patients (average age, 61.8 years) with BOOP underwent computed tomography examinations. The examination technique included a slice thickness of 4 mm with a 4-mm interval; matrix size was 256 x 256 pixels. In all patients, additional HRCT images with a 2-mm slice thickness and a 10-mm interval (matrix, 512 x 512 pixels) were obtained. Interpretation included assessment of pulmonary, pleural, and mediastinal involvement. Special attention was paid to the distribution pattern of pulmonary abnormalities. RESULTS: High-resolution computed tomography in all patients demonstrated areas of air space consolidation in a multifocal but peripheral distribution. The right lower lobe was involved in 60% of the patients, the left lower lobe in 53%, the middle and right upper lobes in 20%, and left upper lobe in 23%. Five patients had ground-glass opacities in addition to the areas of air space consolidation, with the incidence in these patients being 100% in the right lower lobe. 80% in the left lower and middle lobes, 60% in the right upper lobe, and 20% in the left upper lobe. Nodules were found in two patients, and the left lower and middle lobes were affected in both. In one patient, the right lower lobe was affected. The interstitium was thickened in 66%, with axial involvement in 20%, septal thickening in 30%, and peripheral regions affected in 50%. Bronchiectasis was present in 60% of all patients studied, predominantly located in the lower lobes. CONCLUSION: Bronchiolitis obliterans organizing pneumonia presents a predominant peripheral, bilateral, and nonsegmental distribution, with the lower and middle lobes affected more than the upper lobes.

Adult↗
PubMed1996

Differentiation of delayed kidney graft function with gadolinium-DTPA-enhanced magnetic resonance imaging and Doppler ultrasound.

RATIONALE AND OBJECTIVES: The authors differentiate acute tubular necrosis from transplant rejection in patients with delayed kidney graft function using gadolinium (Gd)-DTPA enhanced magnetic resonance (MR) imaging. METHODS: Twenty-four patients after renal transplantation (10 with normal graft function, 14 with delayed graft function) underwent conventional and Doppler sonography and MR imaging examination after bolus application of Gd-DTPA. Within a time period of 512 seconds, 39 single-slice MR images were obtained. Measurements of signal intensity in three regions of interests (cortex, medulla, renal pelvis) resulted in a graphic description of the dynamics of the contrast enhancement. The time between the start of the scan and the peaks of the curves was measured. RESULTS: In patients with normal graft function the curves reached the peaks between 39 and 55 seconds (cortex), 44 and 61 seconds (medulla), and between 161 and 318 seconds (renal pelvis). Six patients with acute tubular necrosis showed normal values for the curves 1 and 2 but markedly prolonged time for curve 3 (between 420 and 512 seconds). In all patients with histologically proven transplant rejection, the peaks of all curves were not reached before the ends of the scans. CONCLUSION: The authors' preliminary results suggest that MR imaging seems to be a sensitive, noninvasive diagnostic tool to differentiate acute tubular necrosis from transplant rejection in the critical early postoperative period.

Adult↗
PubMed1994

[Fluoroscopically guided percutaneous fine-needle biopsy of the lung using the ROTEX needle: results in 890 patients with focal lung lesions].

Fluoroscopically guided transthoracic fine needle biopsies were performed in 890 patients (380 female, 582 male, mean age: 56 years). In 795 patients (89.4%) the first biopsy was successful. The success rate of biopsy correlated closely with the size of the lesion and increased with larger size. Sensitivity in the diagnosis of malignant lesions was 94.6%, specificity 99.5%. Due to cytological, histological, and clinical confirmation of benign lung lesions in 300 patients (33.7% of all patients), the number of unnecessary diagnostic thoracotomies for benign disease could be reduced significantly. In 9 of 113 cases (8%) histological reclassification of the cytologic results was necessary. Reclassification was not necessary in the differentiation between benign and malignant lesions and between small cell and non-small cell carcinomas. The overall complication rate was 24.7% (220 patients). Only 36 patients (4% of all patients) required chest-tube insertion. There were no fatal complications. Percutaneous fluoroscopically guided transthoracic fine needle biopsy of the lung, performed with the Rotex needle, is a time-effective, safe, and efficient method for diagnosing focal pulmonary lesions.

Adenocarcinoma↗
PubMed1991

Laser angioplasty: results of a prospective, multicenter study at 3-year follow-up.

A prospective multicenter trial was initiated to evaluate the efficacy and safety of laser angioplasty. Laser recanalization was performed in 338 patients with arteriosclerotic femoropopliteal artery occlusions (average length, 8.5 cm). Neodymium-yttrium-aluminum-garnet lasers were used in combination with sapphire probe catheters. The initial recanalization rate was 85%. Complications were observed in 14% of the patients. Emergency surgery was required in 1.5%. The cumulative long-term patency rate of the successfully recanalized arteries was 80%, 70%, 62%, and 57% at 6 months, 1 year, and 2 and 3 years, respectively. The patency rates were not affected by the length of the occlusion and the long-term medication (platelet inhibition vs anticoagulation), but patients with a normal runoff had significantly better patency rates than those with reduced runoff (63% vs 52%, P less than .01). The study has shown that laser-assisted angioplasty is safe and at least as effective as conventional angioplasty.

Adult↗
PubMed1990

[Femoropopliteal laser recanalization--a multicenter study].

Laser-assisted angioplasty was performed in four different hospital centers, following the same treatment protocol and using an Nd-YAG laser with a sapphire-probe catheter. The initial recanalization rate of 259 femoro-popliteal occlusions with a mean length of 7.5 cm was 84%. Dissections or perforations were observed in 10%. An emergency surgical intervention was required in 1.1%. The long-term patency rate of the successfully recanalized arteries was 74% after 2 years. The cumulative cure rate of all 259 patients was 62%.

Adult↗
PubMed1987

[Computerized tomography and myelography findings following lumbar intervertebral disk surgery].

56 patients suspected of having suffered recurrent disc prolapse in the lumbar region were examined by CT and by myelography; the value of these examinations has been analysed. In 32 patients the findings were checked during surgery. There were difficulties in diagnosis, both for CT and myelography, where the findings were complex, i.e. in patients in whom there was postoperative fibrosis as well as disc prolapse and/or osseous spinal canal stenosis. As regards recurrence of prolapse, sensitivity for both methods was 83%. Postoperative scar formation can be clearly demonstrated by CT, but myelography produced a false positive diagnosis of recurrent prolapse in 17%. The changes were, in fact, caused by scar tissue formation.

Cicatrix↗
PubMed1986

Intraarterial fibrinolysis: long-term results.

Intraarterial fibrinolytic therapy was performed in 136 patients suffering from arteriosclerotic thrombosis of the iliac and femoropopliteal arteries. The initial success rate was 78%. Despite anticoagulation therapy, early recurrent thrombosis was observed in 10% of the patients. The 2-year cumulative patency rate after recanalization was 81%. These results are competitive with those of reconstructive vascular surgery. Therefore, intraarterial fibrinolysis has become a viable alternative to surgery in treating segmental peripheral occlusions more than 4 cm in length that are less than 6-9 months in duration.

Adult↗
PubMed1985

[State of the art of digital subtraction angiography in diagnostic angiology].

Digital subtraction angiography (DSA) has become a widely accepted method which has decreased the risks of angiographic investigations. Intravenous DSA is the preferred method for screening investigations of carotid and renal arteries and in postsurgical control studies. Intraarterial DSA will be indicated if a detail information is required. The technical principles of time and energy subtraction will be explained, the different methods of contrast medium application will be discussed.

Angiography↗
PubMed1985

Complications of renal tumor embolization.

In 121 renal tumor embolizations with four different embolic agents (Gelfoam, Ivalon, ethanol, coils) the mean complication rate was 9.9%, with a mortality of 3.3%. Because of the large embolized tumor mass and the severely impaired health of patients, the complication rate in palliative embolizations was about four times as high as in preoperative procedures. Complications most commonly encountered were renal failure and unintentional embolization of nontarget organs.

Adult↗
PubMed1985

[Reduction of the rate of cerebral angiography complications by a standardized study method].

The complications from cerebral angiography encountered in 1034 patients between 1977 and 1982 are described. A standardised technique of cerebral transfemoral catheter angiography is outlined, which helps to reduce the number of complications. The role of the disease for which the examination is done, and the effect of the new contrast media on the risk of the examination, are discussed. Patients with a compromised blood-brain barrier and manifest reduction in cerebral blood flow run a greater risk than patients with other abnormalities. Low osmolar contrast media are better tolerated subjectively. Theoretically, their use would be expected to lead to a reduction in complications but, so far, it has not been possible to confirm this.

Adult↗