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Biomedical subjects

T Roeren

Publications and source records attributed to T Roeren.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Imaging techniques in the preoperative diagnosis of soft tissue tumors. A comparison of MRT, CT, sonography, angiography and conventional x-rays].

In a study on 51 patients with histologically confirmed soft tissue tumors (STT), we retrospectively evaluated the preoperative use of imaging procedures (MRI, CT, ultrasound, angiography, plain film) for identification of tumor size, delineation, and determination of malignancy and tissue type. The findings were correlated with intraoperative findings and histological diagnosis. The overall diagnostic method of choice for preoperative imaging of STT is MRI, followed by CT. Ultrasound, although sensitive, lacks the required specificity. Angiography and plain film can only be used for specific indications, as they generally do not make it possible to stage the tumor. Combining our results with those from the more recent literature, we propose a diagnostic algorithm according to which MRI would generally be performed for preoperative staging of STT. CT and plain film should only be used if bony infiltration is suspected; angiography is indicated for planning intraarterial chemotherapy or embolization or if vascular infiltration is probable.

Adolescent↗
PubMed1991

[Intra-arterial chemotherapy in locally advanced breast carcinomas].

Transcatheter arterial chemotherapy with mitoxantrone was carried out in 9 patients suffering from advanced breast cancer. The anticancer agent was selectively injected in the internal mammary artery. In 2 cases the catheter was super-selectively advanced into a peripheral branch of the internal mammary artery supplying the breast carcinoma. No complication of the transcatheter treatment could be observed. CT examinations for controlling the catheter position showed perfusion of breast cancers between 40 and 90 per cent. Histological examinations of the 7 resected specimens revealed extensive necrosis in all cases. All 7 patients who underwent surgery have been without local recurrence for 3 to 12 months after treatment.

Adult↗
PubMed1991

[4 years' experience with a balloon-expandable endoprosthesis. Experimental and clinical application].

During a 4-year period of clinical application of the balloon-expandable Palmaz stent, a randomized trial comparing stent implantation and traditional balloon angioplasty of iliac arteries in arterial occlusive disease was started. The first long-term results, recorded after 2 years, indicate statistically significant differences in the complication rate (after stenting 2/62 and after angioplasty 5/69) and patency (greater than or equal to 70% of original lumen size upon stent implantation or balloon inflation: 95% after stenting and 72% after angioplasty). Clinical improvement after 2 years was 89% after stenting and 70% after angioplasty. Parallel to the clinical trials, experimental canine artery stenting was performed to evaluate differences in the long-term patency of stents exposed to restricted flow. Significant differences in neointimal healing were found between normally perfused stents and stents with artificially reduced flow: during the total observation period of 6 months the neointimal height was up to 200% higher in flow-restricted stents, while the histological composition of the neointima was the same as with normally perfused stents.

Angioplasty, Balloon↗
PubMed1991

[Renal artery aneurysms].

Between 1980 and 1990, 21 patients with 26 renal artery aneurysms (0.4-16.5 cm in diameter) were diagnosed and treated at the Surgical Center, University of Heidelberg. Surgical reconstructive methods were applied to treat extrarenal and interventional embolization to treat intrarenal aneurysms. The most effective diagnostic method is selective intraarterial angiography. The etiology, age distribution, localization and clinical aspects are discussed. Four bleeding intrarenal aneurysms were embolized with full preservation of renal function (one solitary kidney). After surgical reconstruction of the aneurysmatic vessel, 80% of the hypertensive patients turned normotensive. Follow-up of a nontreated sacciform aneurysm showed total thrombosis within 4 years. In the same period, fixed renal hypertension developed in the patient because of recurrent microembolism in the renal parenchyma. Therefore, we suggest immediate treatment of a renal aneurysm to prevent the development of renal hypertension.

Adult↗
PubMed1990

Placement of balloon-expandable intraluminal stents in iliac arteries: first 171 procedures.

Balloon-expandable intraluminal stents were used to treat iliac artery stenoses or occlusions that failed to respond to conventional balloon angioplasty. One hundred seventy-one procedures were performed in 154 patients, of whom 48 had a limb at risk for amputation. Thirty-six had severe and 70 had moderate intermittent claudication. At the latest follow-up examination (average, 6 months; range, 1-24 months), 137 patients demonstrated clinical benefit, 113 of whom had become asymptomatic. Eleven patients showed no initial benefit, and six improved initially but later developed new vascular symptoms. Complications occurred in 18 patients. In three patients, complications were directly related to the device. Two occlusions were successfully recanalized, and an intramural collection of contrast material secondary to balloon perforation evolved favorably. The remaining patients had groin hematoma (n = 6), distal embolization (n = 4), extravasation (n = 2), transient renal failure (n = 1), pseudoaneurysm at the puncture site (n = 1), or subintimal dissection (n = 1). All stents have remained patent to the latest follow-up examination without evidence of migration or aneurysm formation.

Adult↗
PubMed1990

Interventional radiological treatment of malignant biliary obstruction.

Percutaneous transhepatic procedures have gained a strong position in the diagnosis and treatment of malignant biliary obstruction. Diagnostic cholangiography can easily be converted into therapeutic drainage, which is often the first step towards further diagnostic work-up (biopsy, percutaneous cholangioscopy) and tumour ablation and/or intraductal irradiation. Plastic endoprostheses and balloon- or self-expandable metallic stents are the therapeutic alternatives to achieve permanent internal drainage of bile.

Bile Duct Neoplasms↗
PubMed1989

Angioplasty and stenting of completely occluded iliac arteries.

Percutaneous angioplasty and placement of balloon-expandable intraluminal stents were performed in 12 iliac occlusions in 12 patients. Indications were limb salvage in seven and claudication in five. After successful stenting, ankle-brachial indexes improved by 0.15 or more in 11 of 12 patients (mean increase, 0.40), transstenotic pressure gradients decreased to less than 5 mm Hg (mean, 0.58 mm Hg) in all patients, and improvement in clinical grade was seen in all patients. At follow-up at 1-14 months (median, 6 months), ankle-brachial indexes were stable (mean, 0.95), and clinical grades were unchanged in all patients. Complications occurred in two patients; both experienced distal embolization, and one, who was receiving corticosteroid therapy, also suffered stent thrombosis. Local surgical embolectomy was successful in both patients, and the thrombosed stent was recanalized with urokinase. This early experience suggests that stenting may play an important role in the management of iliac occlusions, especially in poor surgical candidates.

Adult↗
PubMed1989

Restenosis and successful angioplasty: histologic-radiologic correlation.

Histologic analysis was undertaken on 24 perfusion-fixed arteries from New Zealand White rabbits that had undergone percutaneous transluminal angioplasty (PTA) of a focal arteriosclerotic lesion in the femoral artery 1 month earlier. Experiments representative of occlusion, restenosis (greater than or equal to 50% stenosis), a good result (less than 50% stenosis), or aneurysm (as defined angiographically) were randomly selected for histologic analysis. Histologic findings were compared with those in untreated control lesions in the contralateral femoral artery. All good results (n = 11) but only four of seven restenoses had histologic evidence of a tear into the tunica media or the tunica adventitia (P = .017). Cases of tears to the adventitia were more likely to have a good result. New myointimal proliferation was more severe with restenosis (P less than .05). Occlusions and aneurysms appeared to be more severe expressions of the histologic findings observed in restenoses and good results, respectively. An arterial tear is necessary but not sufficient to obtain a good result after PTA; outcome is ultimately dependent on the degree of intimal hyperplasia.

Angiography↗
PubMed1988

Photoplethysmographic documentation of improved microcirculation after pentoxifylline therapy.

Pentoxifylline is the prototype of a new class of drugs that improve peripheral blood flow mainly by increasing red blood cell flexibility. Few studies have been performed to objectively evaluate the effect of the drug in a routine clinical setting. In 11 patients with intermittent claudication, photoplethysmography was used to monitor the effect of pentoxifylline on the microcirculation in the lower extremities. Values obtained improved significantly (p less than .0001) under therapy. Concomitant measurements of ankle-brachial indices showed no significant changes despite clinical improvement. Diabetic patients in this study seemed to benefit from treatment with pentoxifylline at least as much as nondiabetic patients. Photoplethysmography proved to be a very efficient and inexpensive method of studying the effects of pentoxifylline. Ankle-brachial indices are not a suitable method of detecting flow changes attributable to the mechanism of action of this drug.

Follow-Up Studies↗
PubMed1988

Sources of error in arterial morphometric measurements.

The authors used radiopaque vascular casts to test a new computer-based analysis method that employs a densitometric profile to determine arterial diameters. Results from this method were compared with those obtained with caliper measurements of overhead projection images of the radiograph and direct caliper measurements of the vascular cast. In addition, the corresponding in vivo angiograms were compared with the measurements obtained from the vascular casts. Vessel diameters obtained from cast radiographs by caliper measurement, operator-determined and automated densitometric curve fitting showed excellent correlations with acceptable intraobserver and interobserver variation. All methods, however, underestimated arterial diameters by about 7% compared with diameters obtained from casts by direct caliper measurements. In vivo angiograms revealed smaller arterial diameters than those obtained from specimens. However, we observed higher correlations for measurements at stenotic sites than in non-stenotic regions. Our results suggest definite limitations for the often used direct comparison between in vivo angiographic and postmortem findings.

Angiography↗
PubMed1987

[Dissolution of a bile duct stone with methyl tert-butyl ether].

Methyl-t-butylether is a new agent to dissolve gallstones. The substance proves to be very successful and acts very rapidly. A percutaneous transhepatic drainage supplies an adequate access route to dissolve calculi within the bile ducts. We report the case of a patient where before insertion of an internal stent a stone in the common bile duct was dissolved within 3 1/2 hours.

Aged↗
PubMed1987

[MR of the urinary tract in pregnancy].

A report on the application of standard 2D-FT MR combined with RARE-MR-Urography in a pregnant woman with right sided abdominal pain, dilated upper urinary tract and possible stone or inflammatory disease. This technique visualised the complete obstructed ureter in relation to the surrounding organs (uterus, vessels), allows precise diagnosis of the cause of the obstruction and avoids ionising radiation.

Adult↗