Biomedical subjects

S Thurnher

Publications and source records attributed to S Thurnher.

51 records · Page 3Linked to original sources

PubMed1988

Recurrent thyroid carcinoma: characteristics on MR images.

Magnetic resonance (MR) imaging was used in 32 patients, including eight with benign disease, after partial or total thyroidectomy to determine sensitivity and specificity of MR imaging in the detection of tumor recurrence, to compare signal intensities of scar versus recurrent tumor qualitatively and quantitatively, and to define the extent of recurrent tumor. Findings from surgery (n = 23), needle biopsy (n = 1), or clinical follow-up (n = 8) were used for verification. Of 24 patients with primary thyroid carcinoma, 15 had recurrence and nine had a normal postsurgical thyroid bed. Diagnosis from MR images was correct in 20 cases, but false positive in three and false negative in one. Local recurrence was characterized by low to medium intensity on short repetition time (TR)/short echo time (TE) images and medium to high intensity on long TR/long TE images. Scar in the normal postsurgical thyroid bed showed low intensity on both short and long TR/TE images. Local recurrence of thyroid carcinoma and lymph node metastasis produced positive contrast compared with muscle on short TR/short TE (31 + 19%) and long TR/long TE (85 + 30%) images; fibrosis produced negative contrast, particularly on long TR/long TE (-56, -80%) images. These results indicate the capability of MR imaging in the evaluation of recurrence of thyroid tumors and in the differentiation of abnormal tissue due to tumor recurrence from postoperative fibrosis by means of signal contrast relative to a reference tissue.

Adult↗

PubMed1988

Vagina: evaluation with MR imaging. Part I. Normal anatomy and congenital anomalies.

The appearance of the vagina was evaluated on magnetic resonance (MR) images of 65 subjects who were healthy or had disease unrelated to the vagina and 24 patients with suspected congenital anomalies of the vagina. MR imaging accurately demonstrated the presence of (n = 78) or complete (n = 7) or partial (n = 4) absence of the vagina in each case. Partial (n = 2) or complete (n = 2) duplication of the vagina was also correctly diagnosed. Regardless of field strength, T2-predominant images were essential for evaluation. The transverse plane was optimal, and a 5-mm section thickness was preferable. Estrogen stimulation affected the appearance of the vagina: The contrast between the vaginal wall and the central mucus-containing area was greatest during the early proliferative and late secretory phases. MR imaging offers unique depiction of congenital anomalies and should be used when results of physical examination or other radiologic studies, such as ultrasound, are inconclusive.

Disorders of Sex Development↗

PubMed1988

Vagina: evaluation with MR imaging. Part II. Neoplasms.

The potential of magnetic resonance (MR) imaging in the detection of vaginal tumors and the assessment of their extent was evaluated retrospectively in 87 patients in whom primary, metastatic, or recurrent vaginal cancer was clinically suspected. MR findings were compared with the results of surgery and/or biopsy. Results of histopathologic study verified a normal vagina in 51 patients, benign cysts in two, primary tumor in four, metastatic cancer in 22, and recurrent tumor in eight. MR imaging demonstrated the two benign cysts, correctly depicting their size and location, and demonstrated and enabled correct staging of the four primary tumors. MR accuracy for demonstrating metastatic cancer was 92%, sensitivity was 95%, and specificity was 90%. Tumor extension to the vagina was reliably excluded (negative predictive value = 97%), but false-positive interpretations occurred (positive predictive value = 84%) primarily because inflammation (n = 2) and congestion (n = 2) could not be distinguished from tumor invasion. An additional role of MR imaging was the ability to differentiate tumor from fibrotic tissue in patients with suspected recurrent vaginal carcinoma. The overall accuracy of MR imaging for recurrent vaginal cancer was 82% (14 of 17).

Adult↗

PubMed1988

Diagnosis of recurrent hyperparathyroidism: comparison of MR imaging and other imaging techniques.

Several reports have indicated good results with MR imaging of hyperparathyroidism. However, its use in recurrent hyperparathyroidism has not been assessed separately. Thirty patients with recurrent hyperparathyroidism were evaluated by MR with both T1- and T2-weighted images. Twenty-six and 23 of these patients, respectively, also had thallium-201 scintigraphy and high-resolution sonography. For the 28 patients who eventually had surgical exploration and histologic evidence of adenoma (21 cases) or hypoplasia (seven cases), MR accurately located abnormal parathyroid glands in 75% evaluated prospectively and 89% evaluated retrospectively. Scintigraphy located 68% prospectively and 76% retrospectively. Sonography detected 57% prospectively and 67% retrospectively. For patients undergoing three studies, the prospective and retrospective detection rate was significantly better (p less than .05) for MR compared with sonography but was not significantly different for MR and scintigraphy. MR detected three of four mediastinal adenomas evaluated prospectively and retrospectively. One false-positive case was seen with MR, one with scintigraphy, and one with sonography. Thus, MR can be used to locate abnormal parathyroid tissue at a rate equal to or better than scintigraphy or sonography.

Adenoma↗

PubMed1988

[CT and MRT following liver transplantation].

The potential technical complications after liver transplantation are numerous. CT is most useful in the evaluation of the hepatic parenchyma and in the identification of perihepatic fluid collections. CT provides complementary data when the sonographic findings in cases with suspected vascular or biliary complications are unclear. The value of MRI in the evaluation of liver transplants has not yet been fully determined. In patients with complex venous hemodynamics MRI can add useful information.

Humans↗

PubMed1987

[Intraoperative radiotherapy of malignant pancreatic tumors--initial results].

Thirteen patients suffering from adenocarcinomas of the pancreas were submitted to an intraoperative fast electron "boost" therapy with or without percutaneous photon irradiation. A duodeno-cephalo-pancreatectomy with subsequent irradiation of the tumor bed could be performed in three patients. Ten patients were inoperable because of advanced tumors and formation of metastases. The average survival is 6.5 months, at present six patients are alive without major troubles. An analgetic effect was obtained in ten patients. The first results are encouraging with respect to local control, the little acute and chronic morbidity, and palliation achieved in advanced stages.

Adenocarcinoma↗

PubMedDate not supplied

Malignant insulinoma: permanent hepatic artery embolization of liver metastases--preliminary results.

PURPOSE: To evaluate permanent hepatic artery embolization of liver metastases of malignant insulinoma as a therapeutic procedure. METHODS: Three female patients had persistent severe hypoglycemia after distal pancreatectomy because of a malignant insulinoma. Computed tomography (CT) and CT-portography (CTAP) were used for tumor assessment and follow-up and demonstrated multiple hypervascular metastases 0.5-3 cm in diameter in both lobes of the liver. Unilobar sequential transcatheter embolization of the hepatic artery was performed with an interval of 1-2 months between the procedures. Permanent occlusion was achieved by using a mixture of n-butyl-2-cyanoacrylate and ethiodized oil as an embolizing agent. RESULTS: In all patients, embolization of the hepatic artery was technically feasible and complete occlusion could be obtained. In two patients, collaterals originating from the right inferior phrenic artery were embolized superselectively 3 months after bilobar embolization. CTAP at that time revealed marked decrease in tumor size of more than 50%. All patients responded to the treatment as confirmed by normalization of measurable hormone levels, glucose levels, and disappearance of symptoms. Two patients are still alive after 24 and 31 months from the time of the first embolization. Current investigations revealed normal laboratory data and no further tumor progression in the liver. The third patient died 15 months after the first embolization; she also had developed ileus due to local recurrence of the primary tumor and lymph node metastases. CONCLUSION: Hepatic arterial embolization appears to be an effective means of palliation for liver metastases of malignant insulinoma. Long-term improvement seems most likely to be the result of extensive ischemia from permanent occlusion.

Embolization, Therapeutic↗

PubMedDate not supplied

Spiral computed tomographic angiography of the renal arteries: a prospective comparison with intravenous and intraarterial digital subtraction angiography.

PURPOSE: To assess the accuracy of computed tomographic angiography (CTA) in the evaluation of the renal arteries in comparison with intravenous (IVDSA) and intraarterial digital subtraction angiography (IADSA). METHODS: In 18 patients, 35 CTAs and DSAs (27 IADSA, 8 IVDSA) of the renal arteries were performed. CTA was done with 2-3 mm collimation,2-4 mm/sec table speed, after intravenous injection of 80 ml of contrast medium at 4 ml/sec with a scanning delay time of 14-21 sec. No previous circulation time curve was performed. CTA data were reconstructed with maximum intensity projection (MIP) and shaded surface display (SSD). The presence of stenosis was assessed on a three-point rating scale (grade 1-3). The quality of the examinations; visualization of the ostium, the main artery, and its branches; vessel sharpness, linearity, and intraluminal contrast filling were evaluated. We compared CTA with DSA. RESULTS: CTA had 96% sensitivity, 77% specificity, and 89% accuracy in the detection of stenoses > 50%. Due to technical errors two stenoses were erroneously diagnosed as positive but there were no false negative diagnoses. The quality of CTA was good in 56% and moderate in 34% of cases. Visualization of the ostium and main artery was graded as 1.74 (out of 2) points and of the renal branches as 1.02 (out of 2) points and of the renal branches as 1.02 (out of 2) points. The quality of CTA images was worse than that of IADSA in 52%, equal in 41%, and better in 7% of cases. CTA was equal to IVDSA in 25% and better in 75% of the cases. CONCLUSION: CTA is an accurate noninvasive method for the evaluation of renal arteries. Examination quality is essential for the diagnosis. CTA is limited in its ability to visualize the branches of the renal artery and accessory arteries. CTA seems to be superior to IVDSA.

Adult↗

PubMedDate not supplied

Embolization of iatrogenic vascular injuries of renal transplants: immediate and follow-up results.

PURPOSE: To evaluate the outcome in seven patients in whom iatrogenic vascular complications were treated with catheter embolization. METHODS: Angiography showed an arteriovenous fistula in six of the seven patients, a pseudoaneurysm in three patients, and an arteriocaliceal fistula in three patients. Embolization was performed with GAW coils or microcoils in all cases. In three patients enbucrilate, polyvinyl alcohol, or absorbable gelatin powder was administered as an adjunct to the coils. RESULTS: Angiographic success with total occlusion of the vascular injury was achieved in five of the seven patients and clinical success was achieved in four of seven cases. In two cases, nephrectomy after embolization was necessary because of renal artery occlusion or acute hemorrhage at the renal artery anastomosis, respectively. Infarction of 30%-50% of the renal parenchyma was seen in two cases. CONCLUSION: Angiographically successful embolization is not necessarily associated with clinical success. The complication rate is high.

Adult↗

PubMedDate not supplied

Spiral CT during selective accessory renal artery angiography: assessment of vascular territory before aortic stent-grafting.

We evaluated the vascular territory of accessory renal arteries in cases where the vessel might be overlapped by an aortic stent-graft. Spiral CT during selective accessory renal artery angiography was performed in four patients with abdominal aortic aneurysms (including one with a horseshoe kidney). The volume of the vascular territory of each renal artery was measured using a software program provided by the CT unit manufacturer. The supernumerary renal arteries perfused 32%, 37%, 15%, and 16% of the total renal mass, respectively. In two patients, stent-grafts were implanted, which resulted in occlusion of the supernumerary renal artery. The volume of the renal infarction was equal to the volume perfused by the artery as calculated before implantation of the stent-graft. The method proposed is accurate for estimating the size of the expected renal infarction. It might help to determine whether placement of a stent-graft is acceptable.

Aorta, Abdominal↗

PubMedDate not supplied

Primary implantation of polyester-covered stent-grafts for transjugular intrahepatic portosystemic stent shunts (TIPSS): A pilot study.

PURPOSE: To investigate whether placement of a polyester-covered stent-graft increases the primary patency of transjugular intrahepatic portosystemic stent shunts (TIPSS). METHODS: Between 1995 and 1997 Cragg Endopro or Passager MIBS stent-grafts were used for the creation of TIPSS in eight male patients, 35-59 years of age (mean 48 years). All patients suffered from recurrent variceal bleeding and/or refractory ascites due to liver cirrhosis. Seven stent-grafts were dilated to a diameter of 10 mm, one to 12 mm. Follow-up was performed with duplex ultrasound, clinical assessment, and angiography. RESULTS: The technical success rate for creation of a TIPSS was 100%. The mean portosystemic pressure gradient decreased from 25 mmHg to 12 mmHg. In seven of eight patients TIPSS dysfunction occurred between 2 days and 3 years after stent-graft placement. In one patient the TIPSS is still primarily patent (224 days after creation). The secondary patency rates are 31 days to 3 years. CONCLUSION: The primary use of polyester-covered stent-grafts for TIPSS did not increase primary patency rates in our small series.

Adult↗

PubMedDate not supplied

The Erasme study: a multicenter study on the safety and technical results of the Palmaz stent used for the treatment of atherosclerotic ostial renal artery stenosis.

PURPOSE: To assess, in a multicenter setting, safety, technical results, and restenosis rate of the Palmaz stent for treatment of atherosclerotic ostial renal artery stenosis. METHODS: Ten centers enrolled 106 patients (120 treated renal artery stenoses) in the study. Patient selection was based on unsuccessful percutaneous transluminal renal angioplasty (residual stenosis >/= 20%) performed for treatment of ostial stenosis >/= 50%, in patients with hypertension and/or impaired renal function. Safety was assessed by means of the complication rate, and technical results by the number of successful stent placements and occurrence of restenosis (>50%) at intraarterial angiographic follow-up. RESULTS: Stent placement was successful (n = 112) or partially successful (n = 5) in 117 (98%) arteries. Complications occurred in 19 procedures; seven were of serious clinical significance. Angiographic follow-up was performed in 89 of 117 (76%) cases, at a mean of 8 months (range 2. 5-18 months). Fifteen stents (16.9%) showed restenosis (at a mean of 8.5 months), of which 10 were successfully redilated. CONCLUSION: Renal artery stenting has a high technical success rate, a complication rate comparable to percutaneous transluminal renal angioplasty, and a low rate of restenosis at 8 months angiographic follow-up.

Aged↗

PubMedDate not supplied

Magnetic resonance imaging of splenic iron overload.

The value of magnetic resonance (MR) imaging in assessing iron overload in the spleen was retrospectively investigated in 40 consecutive patients. MR appearance, measure of signal intensity and T1- and T2-relaxation times were correlated with the histologically determined level of iron in the spleen in each patient. Histologic examination revealed no iron overload in 19 patients, mild iron overload in seven, moderate iron overload in six, and severe iron overload in eight. All 19 patients with no splenic iron overload and 11 of the other 21 patients with splenic iron overload were correctly identified by MR imaging (sensitivity 52%, specificity 100%, accuracy 75%). Splenic iron overload was diagnosed when a decrease of signal intensity of the spleen compared with those of adipose tissue and renal cortex was demonstrated. MR images demonstrated all eight cases of severe, three of the six cases of moderate, and none of the seven cases of mild iron overload. Only spleens with severe iron overload had a significant mean decrease in signal intensity and T1- and T2-relaxation times. Although specific, MR imaging is poorly sensitive to splenic iron overload.

Adolescent↗

PubMedDate not supplied

Gadolinium-DOTA enhanced MR imaging of adnexal tumors.

We conducted a retrospective study to assess the potential of contrast enhanced magnetic resonance (MR) imaging in evaluating adnexal tumors. Sixty patients with a total of 77 pelvic lesions underwent MR imaging at 1.5 T and transabdominal ultrasound (US). Precontrast T1- and T2-weighted and Gd-DOTA enhanced T1-weighted MR images were obtained. Diagnoses were proved by surgery in 57 patients. Of the 77 lesions, 54 masses were of ovarian origin, including 12 malignant disorders. Ultrasound demonstrated the lesions in 92%, whereas the sensitivity of unenhanced T2-weighted and postcontrast MR images was 98 and 96%, respectively. Compared to the T2-weighted images, postcontrast MR imaging showed superior overall tumor delineation, assessment of intratumoral architecture, and definition of tumor origin. Contrast enhancement of tumors did not differ significantly between normal ovary and benign and malignant lesions. All modalities were unable to predict malignancy of complex lesions. Based on our study, US remains the screening modality of choice in the evaluation of adnexal tumors. Contrast enhanced MR imaging may be valuable for assessing complex lesions or when the origin of the mass cannot be determined by US. Using contrast enhanced T1-weighted images instead of T2-weighted images may lead to a significant reduction in acquisition time.

Adnexal Diseases↗

PubMedDate not supplied

Spiral CT angiography in the assessment of abdominal aortic aneurysms after stent grafting: value of maximum intensity projections.

PURPOSE: Our goal was to evaluate the value of maximum intensity projections (MIPs) rendered from spiral CT in the assessment of abdominal aortic aneurysms after stent graft implantation. METHOD: Spiral CT of the aorta was performed in 28 patients 1 week after implantation of covered aortic stent grafts. MIPs were evaluated in a blinded fashion. Transaxial scans and intravenous angiographs were considered the reference standard. RESULTS: Stent deformity was evident on the MIPs in 5 cases and stent angulation was seen in 24 cases. The excluded aneurysmal sac was visualized in 14 (50%) cases. MIPs depicted the patent inferior mesenteric artery in 20 of 23 cases (87%). Renal artery occlusion (n = 3), leaks (n = 8), and parietal thrombi, (n = 3) were detected on the MIPs in all cases. CONCLUSION: MIPs are a valuable tool in the assessment of aortic stent grafts.

Aged↗