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D Strobel

Publications and source records attributed to D Strobel.

At least 19 recordsLinked to original sources
PubMed2005

Contrast-enhanced sonography for the characterisation of hepatocellular carcinomas--correlation with histological differentiation.

AIM: We aimed to characterise the vascularisation patterns of hepatocellular carcinomas in contrast-enhanced sonography in correlation to the histological differentiation of hepatocellular carcinomas (HCC), and we also compared the diagnostic value of contrast-enhanced sonography in addition to B-scan sonography and power Doppler sonography. METHODS: 51 hepatocellular carcinomas (21 well differentiated, 27 moderately differentiated, 3 poorly differentiated) were examined: by B-scan sonography, power Doppler sonography and contrast-enhanced sonography using phase or pulse inversion harmonic imaging with a low mechanical index (< 0.3) and second generation microbubble contrast medium (Optison, Sonovue) as echo-enhancing agent. Lesion vascularity and the kinetics of contrast enhancement within the lesions in the early arterial phase, arterial phase, portal phase and late phase were analysed. The final diagnosis of a HCC was assessed after B-scan sonography, power Doppler sonography and contrast-enhanced sonography. RESULTS: Hypervascularisation and/or irregular tumour vascularisation could be detected in 18/48 HCCs (37.5%) by power Doppler sonography. After contrast application, 46/51 HCCs (90.2%) were identified as hyperechoic lesions during the early arterial or arterial phase with no correlation to histological differentiation. In the portal phase and late phase, the echogenicity of HCCs after contrast application was variable. A hypoechoic appearance was noted in 17/51 HCCs (33.3%) in the portal phase and in 21/51 HCCs (41.2%) in the late phase. Moderately differentiated HCCs were more often hypoechoic than well differentiated HCCs (p = 0.04). CONCLUSION: Contrast-enhanced sonography is highly efficient for the detection of tumour vascularity in HCCs. The majority of HCCs--regardless of histological differentiation--can be characterised as hypervascular lesions in the early arterial and arterial phase with irregular tumour vessels using contrast-enhanced sonography. In addition to B-scan sonomorphology, contrast-enhanced sonography may offer helpful information in patients with liver cirrhosis and focal liver lesions.

Carcinoma, Hepatocellular↗
PubMed2005

Hepatic transit time: indicator of the therapeutic response to radiofrequency ablation of liver tumours.

The aim of this study was to evaluate changes of hepatic transit time (HTT) in patients treated by radiofrequency ablation (RFA). Five consecutive patients (2 females, 3 males; mean age 66 years) referred for treatment of liver neoplasm with percutaneous application of RFA were included in this study. The HTT of contrast agent (Sonovue(R); Bracco International B.V., Amsterdam, The Netherlands) was measured in patients with liver metastases on the basis of time intensity curve (TIC(R)) before and after RFA, respectively. Changes of HTT before vs after RFA were compared with therapeutic response based on three-phase dynamic CT or MRI. Before RFA HTT in all 5 patients was less than 10 s (mean 6.2+/-1.5 s). After RFA HTT in patients with complete therapeutic response was 11.3+/-1.2 s, whereas two patients with incomplete treatment showed unchanged HTT below 10 s (mean 6.3+/-1.8 s). Successful RFA leads to a normalization in HTT. HTT using ultrasound contrast agent appears to provide a new and alternative approach in assessing the therapeutic effect of RFA in liver metastases.

Aged↗
PubMed2003

[Radio-frequency-ablation (RFA) with wet electrodes in the treatment of primary and secondary liver tumours].

INTRODUCTION: The majority of patients with primary and secondary tumours of the liver cannot be treated curatively by surgery. The treatment of these patients with radio-frequency thermoablation using perfused needle applicators (wet electrodes) was evaluated in a feasibility study. METHOD: Patients with primary and secondary tumours of the liver and contraindications against surgery or LTX were included into the feasibility study. RFA was performed percutaneously under ultrasound guidance. The patients were followed up sonographically and by computed tomography. RESULTS: 20 patients (9 male, 11 female) with 35 lesions were treated with RFA. 12 patients (22 tumour locations) suffered from HCC and 8 patients (13 tumour masses) had liver metastases (colorectal, breast, pancreas, carcinoid). The median age was 65.6 years (36 to 83 years). The median tumour size was 33.5 mm. 59 RFTA applications (1.7 applications per tumour mass) were performed. The mean duration of RFTA per patient was 16.2 minutes. During the procedure isotonic saline was injected at a mean flow rate of 6.63 ml/min. All patients received local anaesthesia. In 33 sessions an additional analgosedation was necessary (average dose 63.8 mg Pethidine and 1.4 mg Midazolam). In 2 cases a reduction of the haemoglobin level, occurred, necessitating a blood transfusion. 3/4 of the treated metastases could be eradicated completely. Within a median follow-up of 145 days no intrahepatic local recurrence but 4 distant metastases occurred. 2/3 of the treated HCC could initially be brought into complete remission (CR). After a median follow-up of 329 days 5 of the 8 initially successfully treated patients with HCC were still in complete remission. In 3 cases an intrahepatic local recurrence developed. CONCLUSION: RFA with wet electrodes is a safe, effective and inexpensive treatment for primary and secondary tumours of the liver, measuring less than 4 cm in diameter.

Adult↗
PubMed2003

[Detection of liver metastases--comparison of contrast--enhanced ultrasound using first versus second generation contrast agents].

AIM: To compare detection rates for liver metastases for conventional ultrasound, US using tissue harmonic imaging (THI), echo-enhanced pulse inversion harmonic imaging using Optison and Levovist. METHOD: In 73 patients with histologically proven gastrointestinal tumors spiral CT (S-CT), conventional US, US in the THI-mode, echo-enhanced ultrasound in the portal venous phase (ECI Optison ) and in the liver specific late phase (ECI Levovist) were performed and reviewed by blinded readers. RESULTS: 73 patients (25 female, 48 male, age 63 +/- 11) were included. S-CT detected 158 liver metastases. Conventional US detected 117, THI 119, ECI Optison 169 and ECI Levovist 166 liver metastases. Especially for small (< 2 cm) liver metastases and metastases near the diaphragm echo-enhanced ultrasound exceeded conventional US (p < 0.001). Between both echo enhancers there was no significant difference. CONCLUSION: Using echo enhancers increases the ultrasound detection rate significantly. Examination in the portalvenous phase using a second generation enhancer (Optison) is equal to a late-phase examination using Levovist.

Contrast Media↗
PubMed2003

Radiofrequency ablation of hepatocellular carcinoma with a saline solution perfusion device: a pilot study.

PURPOSE: The majority of patients with hepatocellular carcinoma (HCC) cannot be treated with surgery. This study evaluated the treatment of patients with radiofrequency ablation (RFA) with use of needle applicators perfused with isotonic saline solution. MATERIALS AND METHODS: Twenty patients with a maximum of three HCCs as large as 60 mm and a contraindication to partial liver resection or orthotopic liver transplantation were enrolled in the study. They were treated with ultrasound-guided RFA with use of perfused needle applicators and followed with sonography and computed tomography. RESULTS: Twenty patients (14 men, six women) with a total of 29 HCCs were treated with RFA. In total, 56 RFA treatments were performed. Mean HCC size was 31 mm (range, 10-60 mm). Two cases of self-limiting bleeding requiring transfusion of blood products took place. Complete response (CR) was achieved in 85% of patients (17 of 20). Partial response occurred in three tumors 45 mm in diameter or larger. There was a total of six local recurrences in five patients (25% of patients, 21% of tumors). Six patients (30%) exhibited distant recurrence, two of whom also showed local recurrence. In three patients, repeat treatment led to renewed CR. After a median follow-up of 445 days (range, 114-1,071 days), 12 patients (71% of the 17 patients with initial CR) still showed CR. Twelve patients (60% of all patients, 71% of those with initial CR) survived. Three of the eight patients who died were free of viable tumor at the time of death. CONCLUSIONS: RFA with use of perfused needle applicators shows promise as an effective method for treating inoperable HCC. The most frequent complication was bleeding.

Aged↗
PubMed2002

Surgery of a splenic artery aneurysm during pregnancy.

We report a case of ligation of the splenic artery with splenectomy during pregnancy due to a splenic artery aneurysm. The risk of aneurysmal rupture is increased in multipara and during pregnancy. As a result of high maternal and fetal morbidity and mortality elective surgery should be performed.

Adult↗
PubMed2002

[Hepatic transit time of an ultrasound echo enhancer indicating the presence of liver metastases - first clinical results].

AIM: This pilot study examines the question whether the transit time of an ultrasound echo enhancer, measured between the hepatic artery and the liver vein, can be used to differentiate between patients with and without liver metastases. METHOD: The hepatic transit time of an ultrasound echo enhancer (Optison(R)) was determined using the pulse-inversion mode in patients suffering from gastrointestinal tumours. A group with histologically verified liver metastases was compared to a group without liver metastases. RESULTS: 24 patients have been included in the study so far. 7 patients had liver metastases from a still existing primary tumour (group A). Five patients showed liver metastases after removal of the primary tumour (group B). Six patients had a primary tumour, but no liver involvement (group C), and six patients had neither a primary tumour nor any liver disease. The mean hepatic transit time in group A and B came to 7.4 seconds. Group C and D had a transit time of 16 and 15.5 seconds, respectively. This shows a significant difference in hepatic transit time between patients with liver metastases (groups A and B) compared to those without (groups C and D). The presence of a primary tumour did not influence hepatic transit time. CONCLUSION: In this first pilot study using the measurement of hepatic transit time it was possible to differentiate between patients with and without liver metastases.

Contrast Media↗
PubMed2002

[Treatment of a solitary adenoma of the parathyroid gland with ultrasound-guided percutaneous Radio-Frequency-Tissue-Ablation (RFTA)].

Radio-Frequency-Tissue-Ablation (RFTA) for the treatment of primary and secondary tumours of the liver has been used for several years, but this minimally invasive treatment is not limited to the liver. A patient suffering from symptomatic postmenopausal osteoporosis, additionally having primary hyperparathyroidism since 1995, refused a surgical resection of the adenoma of the parathyroid gland. Sonographically a 16 mm hypoechoic tumour dorsal of the right upper pole of the thyroid gland was detected. Osteodensitometry: severe osteoporosis of the lumbar spine (88 % of the norm for this age group). Blood check: Elevation of serum calcium level (3.1mmol/l) and serum parathormone level 274 pg/dl (N: 10-50). A percutaneous ultrasound guided RFTA of the adenoma of the thyroid gland was carried out. After RFTA the serum parathormone levels and the serum calcium levels dropped back to normal. The patient was followed-up for one year. For the first time a sufficient therapy for osteoporosis comprising calcium, etidronate and cholecalciferol could be carried out. The osteodensitometry carried out one year after treatment showed an increase in bone density. For the treatment of symptomatic primary hyperparathyroidism RFTA can be a therapeutic alternative for patients with contraindications for surgery.

Adenoma↗
PubMed2001

Dynamic contrast-enhanced power Doppler sonography improves the differential diagnosis of liver lesions.

The aim of this paper was to investigate the diagnostic value of dynamic contrast-enhanced power Doppler sonography in the differential diagnosis of liver lesions. We prospectively examined 85 focal liver lesions in 71 patients by real-time gray-scale sonography, power Doppler sonography, and contrast-enhanced power Doppler using two ultrasound contrast agents (Levovist, Optison). Amount and architecture of lesion vascularity and the kinetics of contrast enhancement within the lesions were analyzed. Vascularity was detected in 61% of liver lesions (52/85) by conventional power Doppler, compared to 86% (73/85) by contrast-enhanced power Doppler sonography. Dynamic contrast-enhanced power Doppler identified arterial radial hypervascularity <16 s after contrast injection in 19/22 focal nodular hyperplasias (86%). Irregular hypervascularity was seen with contrast enhancement in the arterial phase in 14/15 hepatocellular carcinomas (93%). In 14/25 hemangiomas (56%), a circular vascularization pattern was noted. Specific lesion diagnosis based on B-scan and conventional and dynamic contrast-enhanced power Doppler sonography led to correct diagnosis in 86% (73/85, 95% confidence interval 78%-94%) compared to 57% (48/85, 95% confidence interval 47%-94%) by B-scan criteria and conventional power Doppler sonography. Contrast-enhanced power Doppler sonography improves diagnostic accuracy in the differential diagnosis of focal liver lesions.

Albumins↗
PubMed2001

[Harmonic imaging for improving diagnosis of liver tumors--preliminary report].

UNLABELLED: Contrast harmonic imaging (CHI) is a new Doppler technology using the non-linear properties of ultrasound contrast agents. AIM: In this pilot study contrast harmonic imaging was evaluated for the detection and characterization of liver lesions. METHODS: Tumor vascularity patterns and diagnostic accuracy in the differential diagnosis of liver lesions were compared in 50 liver lesions using gray-scale sonography, unenhanced and enhanced power Doppler sonography and CHI. In addition, CHI was compared to spiral-CT for the detection of liver metastases in 28 patients. RESULTS: CHI was superior to power Doppler sonography in the visualization of vascularity pattern. Due to the better resolution and image quality of tumor vascularity the diagnostic accuracy of CHI in the differential diagnosis of liver lesions was higher (88% CHI versus 40% unenhanced power Doppler, and 58% contrast-enhanced power Doppler). In the detection of liver metastasis CHI showed a higher sensitivity (96.8%) compared to spiral-CT (74.6%) in 28 patients with 63 metastases. CONCLUSIONS: CHI is a promising new ultrasound technology to further improve the differential diagnosis of liver lesions and the detection of metastases.

Albumins↗
PubMed2001

Echo-enhanced color- and power-Doppler EUS for the discrimination between focal pancreatitis and pancreatic carcinoma.

BACKGROUND: EUS is a precise method for detection and staging of pancreatic tumors. However, differentiation between inflammatory pseudotumor and pancreatic carcinoma remains difficult. The aim of this study was to evaluate contrast-enhanced EUS as a method of differentiating inflammation and carcinoma based on perfusion characteristics. METHODS: Patients with solid pancreatic masses underwent EUS with a linear echoendoscope. Perfusion in the pancreatic tissue and the mass was assessed with native and contrast-enhanced EUS with power- and color-Doppler imaging. Examinations were evaluated by a blinded reader. A markedly hyperperfused lesion was considered an inflammatory pseudotumor whereas lesions that were hypoperfused compared with surrounding tissue were considered to be carcinoma. RESULTS: Fifteen of 23 patients had hypoperfusion within the mass and 8 patients had hyperperfused lesions. Of the 15 patients with hypoperfused masses, all had pancreatic adenocarcinoma; 1 of 8 patients with a hyperperfused lesion also had adenocarcinoma. The remaining 7 patients had focal inflammation. Sensitivity for differentiation of pancreatic carcinoma versus inflammatory changes was 94%, specificity 100%. CONCLUSION: Echo-enhanced power-Doppler EUS reliably differentiates pancreatic neoplasm and focal pancreatitis. The diagnostic accuracy of this technique is comparable to CT, magnetic resonance imaging, positron emission tomography, and ERCP.

Adenocarcinoma↗
PubMed2001

Detection of liver metastases: comparison of contrast-enhanced wide-band harmonic imaging with conventional ultrasonography.

OBJECTIVE: To compare the detection rate of conventional ultrasonography and contrast-enhanced wide-band harmonic ultrasonographic imaging in the detection of small liver metastases. METHODS: Consecutive patients with histologically proved gastrointestinal carcinoma liver metastases were studied. Biphasic helical computed tomography, conventional ultrasonography, and contrast-enhanced wide-band harmonic imaging were performed on all patients within a 5-day period. The biphasic helical computed tomographic scans were reviewed and interpreted by a skilled radiologist. The number of lesions and their descriptive characteristics were recorded for analysis. In addition, videotape recordings of the conventional ultrasonography and contrast-enhanced wide-band harmonic imaging were blindly reviewed, after which the number of detected lesions and their characteristics were then compared with those detected on biphasic helical computed tomography, considered the standard of reference. RESULTS: Twenty-eight patients (10 female and 18 male; age range, 45-72 years) were studied. Conventional ultrasonography detected 37 (59%) of all lesions visualized by biphasic helical computed tomography. The detection rate for contrast-enhanced wide-band harmonic imaging was significantly higher (61 [97%] of 63). In our series, two 10-mm lesions near the diaphragm were not visualized by wide-band harmonic imaging. CONCLUSIONS: The use of contrast-enhanced imaging techniques significantly improves the ultrasonographic detection of liver metastases. Our results achieved the sensitivity of biphasic helical computed tomography.

Aged↗
PubMed2000

Clinical evaluation of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors.

PURPOSE: We investigated the value of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors. METHODS: We prospectively examined 105 focal liver lesions in 100 patients by real-time gray-scale sonography, color Doppler sonography, and contrast-enhanced color Doppler sonography with galactose-based microbubbles (SH U 508A; Levovist). The final diagnoses of the liver lesions as confirmed by pathology or additional imaging techniques were 31 metastases, 25 hemangiomas, 19 hepatocellular carcinomas, 19 focal nodular hyperplasias, 2 cholangiocellular carcinomas, and 9 other lesions. RESULTS: Vascularity could be detected in 43 (41%) of the 105 lesions by conventional color Doppler sonography compared to 67 (64%) by contrast-enhanced color Doppler sonography. Contrast-enhanced color Doppler sonography identified moderate or extensive vascularity in all 19 focal nodular hyperplasias, moderate or extensive vascularity in 16 hepatocellular carcinomas and both cholangiocellular carcinomas, and no or minor vascularity in all but 3 hemangioma. The combination of gray-scale, conventional color Doppler, and contrast-enhanced color Doppler sonography led to the correct diagnosis in 81% of cases (85 of 105), compared to 57% (60/105) for gray-scale and conventional color Doppler sonography and 31% (33/105) for gray-scale sonography alone. CONCLUSIONS: Contrast-enhanced color Doppler sonography improves the detection of tumor vascularity and is useful in the differential diagnosis of liver lesions.

Confidence Intervals↗
PubMed2000

[Hepatic Doppler perfusion index--a sensitive screening method for detecting liver metastases?].

UNLABELLED: The sonographic measurement of the Doppler perfusion index (DPI)--the ratio of blood flow in the hepatic artery to total liver blood flow--has been suggested to represent a method of detecting even small liver metastases. AIM: To evaluate the DPI measurement in our patients with liver metastases of colorectal cancer, gastric and bronchial carcinoma. METHOD: 36 patients with liver metastases were compared to 21 control subjects. The hepatic arterial and portal venous blood flows were calculated from the product of the average velocity of flow and the cross-sectional lumen of the vessel. Each measurement was performed three times by two independent examiners. RESULTS: Patients with metastases had a significantly higher hepatic blood flow and a significantly higher DPI (p = 0.0004; M +/- SD 0.23 +/- 0.11; r 0.06-0.52) compared with controls (M +/- SD 0.14 +/- 0.06, r. 0.05-0.26). No significant difference was seen in the portal vein blood flow. The DPI-values measured by the two examiners differed by 25.98% +/- 23.20. CONCLUSION: DPI values in patients with liver metastases differ from those in control subjects due to an increased hepatic arterial blood flow. No clear separation of the two groups was possible because DPI values overlapped. The inter observer agreement in DPI seems clinically acceptable.

Adult↗
PubMed1999

Percutaneous ethanol injection and radio-frequency ablation for the treatment of nonresectable colorectal liver metastases - techniques and results.

BACKGROUND: Percutaneous ethanol injection (PEI) and radio-frequency (RF) ablation are possible palliative treatment modalities for patients with non-resectable liver metastases of colorectal carcinomas. The different techniques are explained and reviewed. RESULTS: PEI did not show promising results for the treatment of liver metastases. RF results were more encouraging; some studies showed improved mean survival times for patients when a complete necrosis of the metastases could be achieved. The maximum diameter of the necrotic area possible in a single session is about 5 cm. CONCLUSION: PEI and RF are palliative last-line treatment strategies for patients with non-resectable liver metastases and should only be applied if chemotherapy is not sufficient or not possible. The long-term efficacy of RF ablation in this group of patients has to be evaluated.

Catheter Ablation↗