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T Balzer

Publications and source records attributed to T Balzer.

At least 19 recordsLinked to original sources
PubMed2006

Imaging characteristics of hepatocellular carcinoma using the hepatobiliary contrast agent Gd-EOB-DTPA.

PURPOSE: To evaluate the ability of contrast-enhanced magnetic resonance imaging (MRI) with Gd-EOB-DTPA in comparison with non-enhanced imaging and spiral computed tomography (CT) to provide additional information for classification and characterization of hepatocellular carcinoma. MATERIAL AND METHODS: Forty patients with histopathology-proven hepatocellular carcinoma were selected for this subgroup analysis from a phase-III multicenter study in 235 patients with known or suspected liver lesions. The primary analysis was comparison of the proportion of hepatocellular carcinoma correctly classified and characterized by combined pre-/post-contrast MRI compared with pre-contrast MRI alone or with spiral CT. All images were evaluated on site, and in a blinded reading by three independent readers off site. RESULTS: In the on-site evaluation, the lesions were correctly classified as a malignant tumor with combined MRI in 90.3%, with pre-contrast imaging alone in 82.9% and with spiral CT in 87.8% (n.s.). The proportion of correct characterization (lesion type diagnosis) with combined MRI was 85.4%, 75.6% for pre-contrast imaging, and 77.5% for spiral CT (n.s.), respectively. In the blinded reading, one reader showed a significant increase in the proportion of correctly characterized lesions by 27% (P<0.05). The other two readers showed a reduction in the proportion of correct characterization by 12% and 15%, respectively (n.s.). CONCLUSION: With regard to lesion classification, no difference was found between combined pre-/post-contrast MRI and spiral CT. A non-significant trend in favor of Gd-EOB-DTPA-enhanced MRI with regard to characterization of hepatocellular carcinoma was found, although the CT scans were not optimized as the MRI scans.

Adult↗
PubMed2002

MR arthrography: pharmacology, efficacy and safety in clinical trials.

OBJECTIVE: A meta-analysis was carried out of clinical trials published between 1987 and 2001 in respect of the clinical pharmacology and safety as well as the diagnostic efficacy of gadolinium-DTPA (Gd-DTPA) for direct intra-articular injection before MRI examination. DESIGN: Scientific papers (clinical, postmortem and experimental studies) and information from the manufacturer regarding intra-articular injection of Gd-DTPA that addressed questions of mode of action, optimal concentration and dose, elimination and safety were reviewed. Clinical studies were classified according to their study design. The sensitivity, specificity and accuracy of MR arthrography (MRA) were compared with a "gold standard" (arthroscopy, arthrotomy) and other radiological evidence for different joints. RESULTS: Fifty-two clinical studies of the overall 112 studies addressed aspects of diagnostic efficacy of MRA in patients or in healthy volunteers. The shoulder was the most assessed joint (29 of 52 studies). Good (>80%) or even excellent (90-100%) sensitivity, specificity and accuracy were found for MRA in most indications, especially for the shoulder and knee joints and induced extension of rotator cuff lesions, labrum abnormalities and postoperative meniscal tears. Two millimoles per liter has proven to be the best concentration for intra-articular administration of Gd-DTPA. After passive complete diffusion from the joint within 6-24 h, complete and rapid renal elimination takes place after intra-articular injection. Local safety proved to be excellent after intra-articular administration of Gd-DTPA. Regarding systemic tolerance almost no side effects have been reported, but the same safety considerations apply for intra-articular administration of Gd-DTPA as for intravenous injection. CONCLUSIONS: The diagnostic efficacy of intra-articular MRA in most clinical conditions affecting major joints is greater than that of plain MRI. In some diagnostic problems MRA achieves almost the same sensitivity and specificity as the surgical gold standard. Given a sterile application, the intra-articular administration of Gd-DTPA in a concentration of 2 mmol/l prior to MRI is a safe procedure.

Arthrography↗
PubMed2001

[Renal enhancement and excretion of the hepatobiliary contrast agent Gd-EOB-DTPA].

PURPOSE: To evaluate the clinical value of the renal clearance using MR imaging with different doses of gadolinium ethoxybenzyl-DTPA (Gd-EOB-DTPA) in comparison to gadolinium DTPA (Gd-DTPA). MATERIAL AND METHODS: In a double-blind and randomized clinical phase II study. MR imaging at 1.5 T was performed in 61 patients with five different doses of Gd-EOB-DTPA (3, 6, 12.5, 25 and 50 micromol/kg b. w. as a bolus injection). The study protocol comprised T(1)- and T(2)-weighted spin-echo magnetic resonance and two-dimensional fast low-angle shot imaging before and at increasing intervals for up to 45 min after injection of Gd-EOB-DTPA. These images were compared with Gd-DTPA-enhanced imaging (0.1 mmol/kg b. w. as a bolus injection). RESULTS: After bolus injection of the hepatobiliary MR contrast agent Gd-EOB-DTPA a renal elimination was observed. Immediately after the injection of Gd-EOB-DTPA until the eighth minute a corticomedullary enhancement of the kidney was conspicuous. After the fourth minute a contrast enhancement could be seen in the renal pelvis. The best enhancement was noted after 20 minutes in the FLASH GRE and T(1)-weighted images with good pelvicaliceal contrast. After 45 minutes an outflow of Gd-EOB-DTPA into the ureter could be observed. CONCLUSION: In addition to the hepatobiliary secretion Gd-EOB-DTPA appears useful for the evaluation of renal structures and renal function on account of the renal excretion without diuretic preparation of the patients.

Adult↗
PubMed1999

Contrast-enhanced 3D-MRA of the upper abdomen with a bolus-injectable SPIO (SH U 555 A).

The purpose of this study was to study temporal changes in signal intensity of liver, spleen, abdominal vessels, and focal liver lesions following iv bolus injection of a superparamagnetic iron oxide (SPIO) using a breath-held three-dimensional magnetic resonance angiography (3D-MRA) sequence. Dynamic SH U 555 A-enhanced 3D-MRA studies were performed in 20 patients with focal liver lesions. Sequential coronal 3D-MRA-FISP scans were acquired (TR 5.0 msec, TE 2.0 msec, flip angle 25 degrees, 140 x 256 matrix, and 80 mm slab) within 15 seconds. Scanning was started immediately after bolus injection of 10 micromol Fe/kg bodyweight and was repeated at multiple time points (baseline and 30, 60, 90, 120, 180, 240, 300, 360, and 420 seconds). Signal intensity values of liver, focal liver lesions, spleen, the portal venous system, the abdominal aorta, and the inferior vena cava were obtained to calculate relative enhancement (ENH = [SI post - SI pre]/SI pre x 100). Visibility of vessels was assessed by consensus of two readers. Signal enhancement within abdominal vessels peaked during the first pass; however, significant signal enhancement was still present 420 seconds following injection. The liver and the spleen also demonstrated a biphasic enhancement pattern with prolonged parenchymal enhancement. Dynamic MRA with bolus injectable SH U 555 A is clinically feasible, and significant vessel enhancement can be achieved even at the dose of 10 micromol Fe/kg bodyweight. However, further refinements are required to improve contrast effects.

Abdomen↗
PubMed1999

Cis-regulatory elements of the mitotic regulator, string/Cdc25.

Mitosis in most Drosophila cells is triggered by brief bursts of transcription of string (stg), a Cdc25-type phosphatase that activates the mitotic kinase, Cdk1 (Cdc2). To understand how string transcription is regulated, we analyzed the expression of string-lacZ reporter genes covering approximately 40 kb of the string locus. We also tested protein coding fragments of the string locus of 6 kb to 31.6 kb for their ability to complement loss of string function in embryos and imaginal discs. A plethora of cis-acting elements spread over >30 kb control string transcription in different cells and tissue types. Regulatory elements specific to subsets of epidermal cells, mesoderm, trachea and nurse cells were identified, but the majority of the string locus appears to be devoted to controlling cell proliferation during neurogenesis. Consistent with this, compact promotor-proximal sequences are sufficient for string function during imaginal disc growth, but additional distal elements are required for the development of neural structures in the eye, wing, leg and notum. We suggest that, during evolution, cell-type-specific control elements were acquired by a simple growth-regulated promoter as a means of coordinating cell division with developmental processes, particularly neurogenesis.

Animals↗
PubMed1998

[T1-weighted dynamic MRI with new superparamagnetic iron oxide particles (Resovist): results of a phantom study as well as 25 patients].

PURPOSE: Evaluation of the diagnostic usefulness of the T1-effect of Resovist (SPIO) for dynamic MRI of the liver. METHOD: In-vitro measurements of a dilution series with T1-weighted FLASH and SE sequences and investigation of 25 patients with known focal liver lesions with a T2-weighted TSE sequence and a dynamic T1-FLASH sequence. RESULTS: T1-weighted MRI with Resovist in vitro showed a positive enhancement at low concentrations and a negative enhancement at higher concentrations. In-vivo T1-weighted dynamic MRI liver parenchyma demonstrated a positive enhancement 30 s post contrast, followed by a continuous slope of signal intensity and a negative enhancement (> or = 60 s). Spleen, portal venous vessels and haemangiomas showed an early increase in signal intensity followed by a decreasing positive enhancement, but without negative enhancement. During the perfusion phase metastases showed a small but not significant increase in signal intensity. In 80% a positive ring enhancement could be observed around metastases. CONCLUSION: Resovist exhibits a diagnostically useful T1-effect. An evaluation of the perfusion of focal liver lesions during the distribution phase is possible with dynamic T1-weighted MRI. This approach may further improve characterisation of focal liver lesions.

Adult↗
PubMed1998

Superparamagnetic iron oxide particles (SH U 555 A): evaluation of efficacy in three doses for hepatic MR imaging.

PURPOSE: To evaluate the efficacy of SH U 555 A in three doses for magnetic resonance (MR) imaging in the liver and to establish the best postinjection time point for liver MR imaging. MATERIALS AND METHODS: Pre- and postcontrast image sets obtained in 169 patients after injection of SH U 555 A (randomly, 4, 8, or 16 mumol of iron per kilogram of body weight). Three blinded readers evaluated the precontrast and 10- and 40-minute postcontrast MR images of 54, 58, and 57 patients, respectively. RESULTS: Statistically significant differences were observed in diagnostic confidence between images obtained with a dose of 4 or 16 mumol Fe/kg (P = .011) and in good or excellent improvement, respectively, in delineation of lesions on 10-minute postcontrast images (P = .001). No apparent differences in the efficacy evaluation were seen between the 10- and 40-minute postcontrast imaging time points. CONCLUSION: There was a dose-dependent postcontrast improvement in evaluated efficacy parameters (diagnostic confidence, visual evaluations) after injection of SH U 555 A. Accumulation phase imaging could begin as early as 10 minutes after administration.

Contrast Media↗
PubMed1997

Enhancement characteristics of liver metastases, hepatocellular carcinomas, and hemangiomas with Gd-EOB-DTPA: preliminary results with dynamic MR imaging.

Our objective was to study Gd-EOB-DTPA for the characterization of focal liver lesions by means of dynamic MR imaging. A double-blind and randomized dose-ranging phase-2 clinical trial was performed in 31 patients (liver metastases n = 23, hepatocellular carcinoma n = 4, and hemangioma n = 4) at a field strength of 1.0 Tesla. Gd-EOB-DTPA (Schering AG, Berlin, Germany) was administered as an IV bolus (12.5, 25, or 50 micromol/kg body weight) with dynamic T1-weighted MRI during the distribution and cellular uptake of the contrast agent at multiple time points up to 45 min post contrast. Dynamic changes in tumor signal intensity, tumor-liver contrast, enhancement patterns, side effects, and adverse events were evaluated. Monitoring of vital signs revealed no significant changes during bolus injection of Gd-EOB-DTPA. Liver metastases demonstrated an inhomogeneous uptake of Gd-EOB-DTPA during the distribution phase with a washout effect on delayed images > 3 min and highest tumor-liver contrast 20 and 45 min post contrast. Hepatocellular carcinomas showed prolonged enhancement as compared with metastases and hemangiomas. Hemangiomas exhibited an early peripheral-nodular enhancement with subsequent partial or complete filling, persisting enhancement < 10 min following injection of Gd-EOB-DTPA, and delayed washout as compared with liver metastases. Initial clinical experience suggests that Gd-EOB-DTPA as a bolus injectable hepatobiliary MR contrast agent may offer useful features for the characterization of focal liver lesions.

Carcinoma, Hepatocellular↗
PubMed1997

[Dynamic and static MRI using superparamagnetic MRI contrast medium Resovist for visualizing primary and secondary liver tumors].

PURPOSE: To analyse characteristics of benign and malignant liver tumours in dynamic and static MR imaging with the superparamagnetic MR contrast medium Resovist. MATERIAL AND METHODS: All 30 patients were examined on a 1.5 Tesla MR unit (Magnetom 63 SP, Siemens AG, Erlangen, Germany) using proton density (PD) weighted (w), T2-weighted-spin-echo, a T1-weighted SE, and a T1-weighted FLASH-2 D gradient echo (GRE) sequence before, during and after the application of Resovist. Dynamic imaging was performed using a T2-weighted GRE-sequence (TurboFLASH; TR/TE = 11/30; flip angle = 10 degrees; Tl = 600 ms). Histopathology revealed benign liver lesions in 8 patients and malignant lesions in 22 patients. RESULTS: Dynamic T2-weighted sequence revealed an early loss of signal intensity in normal liver parenchyma (percentage signal intensity loss (PSIL) = 40.0 +/- 12.2% by 4 mumol Fe/kg, 47.2 +/- 18.8% by 8 mumol Fe/kg and 62.7 +/- 13.0% by 16 mumol Fe/kg), in the spleen, as well as in FNH (PSIL = 49.5 +/- 7.3% by 8 mumol Fe/kg), and regenerating nodules in the first minute after application of Resovist. In two of 4 cases with HCC a short drop in signal intensity was immediately observed after the application, whereas signal intensity remained unchanged in all other malignant liver tumours. Enhanced PDw and T2-weighted SE-sequences revealed an improved detection and delineation of malignant liver lesions versus plain MR imaging. 17 liver lesions of a size lower 10 mm were additionally detected in postcontrast T2-weighted SE-sequences in 4 patients. CONCLUSION: Dynamic and static versus plain MR imaging of primary and secondary liver lesions is markedly improved by the superparamagnetic contrast material Resovist, especially in case of intravenous bolus application of this liver-specific contrast medium.

Adult↗
PubMed1997

[Safety and use of gadobutrol in patients with brain tumors (phase III trial)].

PURPOSE: The purpose of the study was to investigate the use and safety of Gadobutrol, a new low-osmolar, non-ionic contrast agent for MRI using a total dose of 0.3 mmol/kg b.w. on the basis of a clinical phase 3 study. METHODS: 30 patients with primary brain tumours (n = 15) or cerebral metastases (n = 15) were examined via MRI before and after application of a total of 0.3 mmol/kg b.w. given in two fractions (0.1 and 0.2 mmol/kg b.w.). T2-weighted images were performed before, T1-weighted images before, between and after application of contrast material. RESULTS: In this study one-molar Gadobutrol showed a good tolerance. In half of the cases the contrast between lesion and brain was improved comparing single and triple dose, but this means only a slightly improvement of information for the primary brain tumours compared with single dose. The detected metastatic lesions increased in 40% of the patients after the single dose and in 53% of the patients after cumulative triple dose. There was a consecutive change in therapy in 20% of the patients. CONCLUSION: For the differentiation of primary brain tumours the single dose was sufficient, in metastatic lesions triple dose was essential for the detection or exclusion of multifocality.

Adenoma↗
PubMed1997

Detection of focal liver lesions: CT of the hepatobiliary system with gadoxetic acid disodium, or Gd-EOB-DTPA.

PURPOSE: To evaluate the efficacy and safety of gadoxetic acid disodium, or Gd-EOB-DTPA, as a tissue-specific hepatobiliary contrast agent at computed tomography (CT) in patients with liver metastases. MATERIALS AND METHODS: Fifteen patients with known liver metastases underwent CT before and at 30, 80, and, in seven cases, 150 minutes after initiation of intravenous infusion of 0.2, 0.35, and 0.5 mmol Gd/kg gadoxetic acid disodium (five patients per dose group). Attenuation in liver tissue and metastases was measured at each time point. Visualization of metastases, bile ducts, and gallbladder was graded subjectively by two investigators aware of the dose administered and the imaging time point. Patients were monitored for adverse events clinically, and numerous laboratory tests were performed over the 24 hours after administration of the contrast material. RESULTS: The net mean increase in liver attenuation with 0.2, 0.35, and 0.5 mmol Gd/kg was 13 HU +/- 4 (standard deviation), 27 HU +/- 6, and 34 HU +/- 8, respectively. Visualization of liver metastases with doses of 0.35 and 0.5 mmol Gd/kg was graded as good or excellent. Visualization of the gallbladder and common bile duct with doses of 0.35 and 0.5 mmol Gd/kg was improved from minimal to excellent in 89% and 57% of patients, respectively, on 80-minute postcontrast scans. No serious adverse events occurred. Four of 15 patients experienced mild or moderate adverse events possibly or probably related to the contrast medium. Levels of aspartate and alanine aminotransferase increased in three patients by 12-26 and 21-48 U/L, respectively, from normal or moderately elevated baseline levels. These changes may be related to the contrast medium or to the metastases. CONCLUSION: Patient tolerance of gadoxetic acid disodium was acceptable, and liver enhancement and visualization of liver lesions and the biliary system was improved at CT.

Aged↗
PubMed1997

MR imaging of the liver with Resovist: safety, efficacy, and pharmacodynamic properties.

PURPOSE: To evaluate the safety, efficacy, and pharmacodynamic properties of a new superparamagnetic parenteral iron oxide contrast agent for magnetic resonance (MR) imaging. MATERIALS AND METHODS: Thirty-six patients with liver lesions received a bolus injection of Resovist (SH U 555 A; Schering, Berlin, Germany) at a dose of 4, 8, or 16 micromol iron per kilogram body weight (micromol Fe/kg). Fast low-angle shot, spin-echo, and turbo gradient spin-echo MR images were obtained before and 10, 40, and 70 minutes after injection. Blood samples were obtained, vital signs were monitored, and adverse events were recorded. Lesion detection was assessed by two independent, blinded readers. RESULTS: No drug-related adverse events occurred. Serum iron and ferritin levels were increased at all dose levels. Partial thromboplastin time increased and factor XI level decreased 4 hours after injection of 16 micromol Fe/kg. Lesion detection and diagnostic confidence were increased in patients who received 4 or 8 micromol Fe/kg, with no further increase with a 16-micromol dose. CONCLUSION: Resovist is safe and effective. The best MR imaging results were obtained 40 minutes after injection of 8 micromol Fe/kg.

Adult↗
PubMed1996

Color doppler ultrasound of liver lesions: signal enhancement after intravenous injection of the ultrasound contrast agent Levovist.

Patients with focal liver lesions (hemangioma, focal nodular hyperplasia, adenoma, hepatocellular carcinoma, metastatic lesions, focal fatty lesion) received the ultrasound contrast agent Levovist (300 mg/mL and 400 mg/mL) intravenously. This ultrasound contrast agent (a suspension of micrometer-sized microparticles of galactose and microscopic gaseous bubbles) can pass through the lungs without impairment. After the administration of Levovist, increased color flow signals were detected in the liver. Five of 6 patients with metastatic liver lesions showed previously undetected blood flow in the rim of the tumor. In 4 patients with hepatocellular carcinoma, enhanced signal intensity was observed in the vessels of the rim and in 3 of those patients in the center of the tumor. One patient with adenoma and one patient with focal nodular hyperplasia showed signal enhancement in the central area of the tumor. No signal enhancement was observed in hemangiomas, a focal fatty lesion, or in a carcinoid metastatic lesion. Levovist increased the echointensity of normal and tumor vessels in liver lesions. This new ultrasound contrast agent led to the detection of tumor vessels previously not detectable by conventional color flow imaging.

Adenoma↗
PubMed1996

[New MR contrast media in liver diagnosis. Initial clinical results with hepatobiliary Eovist (gadolinium-EOB-DTPA) and RES-specific Resovist (SH U 555 A)].

The purpose of this work is to describe our initial clinical experience (in 66 patients) with Resovist and Eovist, two new liver-specific MR contrast agents. We focus our report on safety aspects, dose finding, and optimization and technical parameters. Both contrast agents were well tolerated and improved the detectability of focal liver lesions. With Resovist, postcontrast MRI may be started as early as 10 min following injection. The dose of 8 mumol Fe/kg bodyweight was sufficient to achieve diagnostic tumor-liver contrast levels. Since Eovist can also be administered as a bolus, dynamic enhancement patterns may be studied for tumor characterization as well. Breath-hold T1-weighted FLASH images were superior to other T1-weighted techniques with and without fat saturation.

Contrast Media↗
PubMed1996

[Does the administration of a high dose of a paramagnetic contrast medium (Gadovist) improve the diagnostic value of magnetic resonance tomography in glioblastomas?].

PURPOSE: To assess the efficacy of high-dose contrast enhanced magnetic resonance imaging (MRI) in detection and delineation of infiltrating tumour in glioblastoma. MATERIAL AND METHODS: In a phase II clinical trial 14 patients with suspected supratentorial glioblastoma underwent MRI with Gd-DO3A-butriol (Gadovist, Schering AG, Berlin) with doses of 0.1 up to 0.3 mmol/kg. RESULTS: Increasing the dose of Gd-DO3A-butriol resulted in improved enhancement (14/14) and better delineation of infiltrating tumour (9/14) up to 2 cm beyond enhancement after standard dose. In two of the 9 patients additional enhancement in the peritumoural oedema was only seen after the third injection. CONCLUSIONS: Successful surgery requires precise preoperative delineation of tumour borders. After high-dose MRI it might be possible to select those patients who would benefit from more radical attempts at eradicating the macroscopic as well as most of the microscopic compartment of glioblastoma.

Contrast Media↗