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W Heindel

Publications and source records attributed to W Heindel.

At least 91 records · Page 5Linked to original sources
PubMed2000

Intra-arterial mitoxantrone and paclitaxel in a patient with Stewart-Treves syndrome: selection of chemotherapy by an ex vivo ATP-based chemosensitivity assay.

We report on a 72-year-old patient developing Stewart-Treves syndrome (STS) of the right arm 9 years after curative irradiation for ipsilateral stage III breast cancer. Facing the poor track record of both irradiation and chemotherapy in this highly malignant lymphangiosarcoma, amputation was recommended but refused by the patient. Therefore, limb conserving-therapy using three courses of intra-arterial mitoxantrone (MX) and paclitaxel (PTX) was attempted. This novel chemotherapy protocol was selected by pretherapeutic ex vivo ATP-based chemosensitivity testing of autologous tumor tissue. The patient experienced complete response, which was subsequent histologically confirmed by compartment resection. When developing recurrent STS outside of the perfused area 6 months after primary therapy, the patient was retested and reinduced with three other courses of intraarterial MX/PTX which again produced durable complete remission. This case demonstrates the benefit of indivdualized therapy in this prognostically desperate disease allowing both limb conservation and maintained quality of life.

Adenosine Triphosphate↗
PubMed2000

Pharmacokinetics of 1M gadobutrol in patients with chronic renal failure.

RATIONALE AND OBJECTIVES: To investigate the pharmacokinetics of 1M gadobutrol as a new neutral MR contrast agent in patients with impaired renal function. METHODS: Twenty-one patients with impaired renal function and any indication for a contrast-enhanced MRI were enrolled into this prospective study and classified in two subgroups according to their creatinine clearance (group 1, 30-80 mL/ min; group 2, 30 mL/min or less, not requiring dialysis). Eleven patients were assigned to the lower dose of 0.1 mmol Gd/kg and 10 patients to the higher dose of 0.3 mmol Gd/kg. To calculate pharmacokinetic parameters, urine and venous blood samples were drawn at baseline and up to 72 hours for group 1 and 120 hours for group 2 after administration of gadobutrol. RESULTS: The predominant extracellular distribution of gadobutrol at steady state did not change according to the degree of renal impairment. The mean elimination half-life of gadobutrol increased to 7.4 +/- 2.6 hours (0.1 mmol/kg) and 5.4 +/- 1.5 hour (0.3 mmol/kg) in group 1 and to 17.9 +/- 6.2 hours (0.1 mmol/kg) and 20.4 +/- 16.9 hours (0.3 mmol/kg) in group 2, compared with 1.5 hours in healthy volunteers. The relation between serum (tbeta) and urine (t(elim)) elimination half-lives, as well as total serum and renal clearance, indicated renal elimination as the main pathway of elimination. The recovery of gadobutrol in the urine of group 1 was complete within 72 hours for both dosage levels. Patients with severe renal impairment showed a mean recovery of 80.1% (0.1 mmol/kg) and 85.3% (0.3 mmol/kg) within the observation period of 120 hours. CONCLUSIONS: The half-life of gadobutrol is prolonged in patients with impaired renal function, but elimination by means of the kidneys is the predominant route.

Case-Control Studies↗
PubMed2000

Magnetic resonance imaging in patients with central nervous system pathology: a comparison of OptiMARK (Gd-DTPA-BMEA) and Magnevist (Gd-DTPA).

RATIONALE AND OBJECTIVES: The objective of the two pivotal phase 3 studies was to evaluate the safety and efficacy of OptiMARK (Gd-DTPA-bis(methoxyethylamide) [Gd-DTPA-BMEA]) compared with Magnevist (Gd-DTPA) in magnetic resonance imaging of the central nervous system. METHODS: Two multicenter, randomized, double-blind, parallel group studies were conducted in 395 patients with known or suspected central nervous system pathology. Subjects were randomized to receive a single 0.1 mmol/kg intravenous injection of either Gd-DTPA-BMEA or Gd-DTPA. The safety of Gd-DTPA-BMEA and Gd-DTPA was monitored for up to 72 hours after study drug administration. Precontrast and postcontrast administration magnetic resonance scans were acquired using identical imaging planes and techniques. RESULTS: No deaths or unexpected adverse events were reported in either group. A comparison of adverse events by intensity and relation demonstrated no statistically significant differences between the two groups. Gd-DTPA-BMEA and Gd-DTPA were equivalent with respect to confidence in diagnosis, conspicuity, and border delineation. CONCLUSIONS: Gd-DTPA-BMEA and Gd-DTPA demonstrated comparable efficacy profiles, and the safety profiles were considered similar.

Adult↗
PubMed2000

Assessment of hemispheric language lateralization: a comparison between fMRI and fTCD.

The cerebral blood flow velocity (CBFV) in the basal arteries during a word-generation task was assessed by functional transcranial Doppler ultrasonography (fTCD) and by functional magnetic resonance imaging (fMRI). The study investigates how event-related CBFV modulations in the middle cerebral artery (MCA) relate to regional cerebral blood flow (rCBF) changes. Both fMRI and fTCD were used in 13 subjects (7 men, 6 women, aged 21 to 44 years). The maximum difference of relative CBFV changes between the left and right MCA during the word-generation task was used as the language laterality index (LIfTCD). For the fMRI examination during the nearly identical language task, the corresponding index was defined by LIfMRI = 100(N(L) - N(R))/(N(L) + N(R)), where N(L) and N(R) refer to the numbers of voxels activated in the left and right hemisphere, respectively. The evoked CBFV changes expressed by LIfTCD and the corresponding laterality index, LIfMRI, estimated by fMRI showed a close linear relation (regression analysis: r = 0.95, p < 0.0001). The results of this study demonstrate that language-related velocity changes in the MCAs relate to rCBF increases in a linear fashion. Since the laterality indices assessed by fMRI and fTCD are in such close agreement both techniques can therefore be used in a complementary way.

Adult↗
PubMed2000

Selenium-based digital radiography in the detection of bone lesions: preliminary experience with experimentally created defects.

PURPOSE: To compare the diagnostic performance of selenium-based digital radiography with that of conventional screen-film radiography and storage phosphor radiography for the detection of bone lesions simulating osteolyses. MATERIALS AND METHODS: Artificial osseous lesions 1.0-3.0 mm in diameter were created in 80 of 160 predefined regions in 16 porcine femoral specimens. Specimens were enclosed in containers filled with paraffin to ensure accurate repositioning and to obtain an absorption condition comparable to that of a human extremity. Imaging was performed with a selenium-based digital radiography system, a conventional screen-film system, and a storage phosphor radiography system with an exposure identical to that used during clinical imaging. The presence of a lesion was assessed with a five-point confidence scale. Receiver operating characteristic (ROC) analysis was performed for a total of 1,440 observations (480 per modality), and diagnostic performance was estimated with the area under the ROC curve (A(z)). Differences in diagnostic performance were assessed with the paired Student t test. RESULTS: ROC analysis results showed A(z) values of 0.656 for selenium-based digital radiography, 0.679 for storage phosphor radiography, and 0.680 for conventional screen-film radiography. Differences between the three modalities were not significant (P =.60-.93). CONCLUSION: Image quality with selenium-based digital radiography was comparable to that with conventional screen-film radiography and storage phosphor radiography.

Animals↗
PubMed2000

Optimized activation of the primary sensorimotor cortex for clinical functional MR imaging.

BACKGROUND AND PURPOSE: One application of functional MR imaging is to identify the primary sensorimotor cortex (M1 and S1) around the central sulcus before brain surgery. However, it has been shown that undesirable coactivation of nonprimary motor areas, such as the supplementary motor area and the premotor area, can interfere with the identification of the primary motor cortex, especially in patients with distorted anatomic landmarks. We therefore sought to design a simple functional MR imaging paradigm for selective activation of the primary sensorimotor cortex. METHODS: Different paradigms using finger tapping for motor activation were examined and compared with respect to the distribution of activated voxels in primary and nonprimary cortical areas. Studies were conducted in 14 healthy volunteers using a blood oxygen level-dependent multislice echo-planar imaging sequence. RESULTS: The most selective activation of the primary sensorimotor cortex was obtained with a paradigm combining right-sided finger tapping as the activation condition with left-sided finger tapping as the control condition. Analysis of the signal time course of primary and nonprimary areas revealed that the highly selective primary motor activation was due to it being restricted to contralateral finger movements, as opposed to the nonprimary motor areas, which were activated by ipsilateral, contralateral, and bilateral finger movements alike. CONCLUSION: When performing functional MR imaging to determine the location of the primary sensorimotor cortex, one should compare unilateral voluntary movements as the activation condition with contralateral movements as the control condition to accentuate activation of the primary motor area and to suppress undesirable coactivation of nonprimary motor areas.

Adult↗
PubMed1999

Does a higher concentration of gadolinium chelates improve first-pass cardiac signal changes?

The purpose of this study was to evaluate first-pass cardiac signal changes with a higher concentrated gadolinium-chelate (gadobutrol) and its influence on bolus geometry. Phantom studies and in vivo first-pass cardiac studies were performed in rabbits (n = 8 experiments) under general anesthesia at 1.0 T using an ultrafast T1-weighted Turbo-fast low-angle shot (FLASH) sequence (TR/TE 4.7/1. 6 msec, alpha = 90 degrees ) with a time resolution of 870 msec. Gadobutrol was injected as an intravenous bolus at two concentrations (0.5 and 1.0 mol Gd/L) and five doses (0.3, 0.15, 0.1, 0.055, and 0.03 mmol Gd/kg bw). The blood-pool gadolinium compound gadopentetate dimeglumine-polylysine (0.15, 0.075, 0.05, and 0.015 mmol Gd/kg bw, 0.5 mol Gd/L) and the standard extracellular gadopentetate dimeglumine (0.1 and 0.05 mmol Gd/kg bw, 0.5 mol Gd/L) served as reference agents. Cardiac signal changes were calculated from serial signal intensity measurements. Maximum signal intensity changes and best peak profiles during first pass of the right and left ventricle were observed with a dose of 0.03 mmol Gd/kg bw gadobutrol using T1-weighted Turbo-FLASH. At the low application volumes used, the higher concentration of 1.0 mol Gd/L gadobutrol did not increase the degree of signal intensity changes or sharpen the bolus profile. First-pass cardiac signal changes using T1-weighted Turbo-FLASH with the new extracellular contrast agent gadobutrol are best observed at a dose of 0.03 mmol Gd/kg bw. There is no advantage to the concentrated formulation (1 mol Gd/L gadobutrol) when using small injection volumes. J. Magn. Reson. Imaging 1999;10:806-812.

Animals↗
PubMed1999

[The MR tomographic imaging of uncomplicated secondary fracture healing exemplified by the distal radius fracture].

PURPOSE: To investigate the normal sequential MR-pattern of uncomplicated fracture healing within the first 6 weeks. METHODS: In 8 patients with distal radius fracture, 4 by 4 with and without intraarticular fracture, MR examinations were performed 3-4 days after the onset of fracture and after 1, 2, 3, 4, 5 and 6 weeks using the following techniques: T1-weighted spin echo, T2-weighted spin echo, T2 proton density weighted, STIR (short inversion time inversion recovery), T2-weighted turbo spin-echo and fast field echo (FFE, gradient echo). Sequential examinations were analysed regarding 1) the appearance of fracture line, 2) development of bone marrow signal, and 3) signal changes in surrounding soft tissue. Maximum contrast of bone marrow and soft tissue was measured. RESULTS: The fracture line in bone marrow was best detectable in FFE- and T2-weighted spin ech images during the first week and in T2-weighted fast spin echo and proton density-weighted images from the 2nd to 4th week. Beginning in the 5th-6th week an increase of signal intensity in the fracture gap was typical in all sequences except for T1-weighted spin echo. The contrast maximum of bone marrow and soft tissue, best detectable in STIR- and T2-weighted spin echo images, occurred in the 1st-2nd week. CONCLUSIONS: MRI shows a typical time-depending pattern of the fracture line, surrounding bone marrow and soft tissue in normal fracture healing. The degree of injury influences the development of signal changes.

Adult↗
PubMed1999

[Primary bone tumors and "tumor-like lesions" of the shoulder. Their histopathology and imaging].

Purpose of this review is to demonstrate typical X-ray, CT and MR morphology of primary bone tumors and "tumor-like lesions" of the shoulder in correlation with histopathology. 711 primary bone tumors of the shoulder and proximal humerus were studied. 602 were localized in the humerus, 90 in the scapula and 19 in the clavicula. The most frequent benign tumors were osteochondromas (n = 143), simple bone cysts (n = 115), enchondromas (n = 75) and aneurysmal bone cysts (n = 50). Fibrous dysplasia (n = 25), chondroblastoma (n = 15), osteoid osteoma (n = 13), giant cell tumors (n = 12) and non ossifying fibroma (n = 11) were less frequent. The most frequent malignant bone tumors were osteosarcoma (n = 72), chondrosarcoma (n = 52) and Ewing's sarcoma (n = 46). Focal plasmocytoma (n = 20) and lymphoma (n = 10) were less frequent. The average age of the patients was 31.5 years. Some of these tumors were typically located in the shoulder, i.e. simple bone cysts and chondroblastoma. In summary the shoulder was a rather infrequent site of primary bone tumors, but since most of these tumors were benign, the radiologist should be aware of the differential diagnosis to guide therapy.

Bone Cysts, Aneurysmal↗
PubMed1999

Spiral CT angiography of the abdominal aorta. Comparison of iodixanol and ioversol.

RATIONALE AND OBJECTIVES: Enhancement characteristics of a nonionic, dimeric, isotonic contrast medium (iodixanol [Visipaque]) were compared with a nonionic, monomeric contrast medium (ioversol [Optiray]) of the same iodine concentration in spiral computed tomography angiography (CTA) of the abdominal aorta. METHODS: Spiral CTA was performed in 78 patients referred for suspected renal artery stenosis (n = 35) and abdominal aortic aneurysm (n = 43). A test bolus was used to time the scan delay, and all patients were injected with 150 ml contrast medium (320 mgI/ml) of either iodixanol (n = 40) or ioversol (n = 38). Contrast enhancement was measured in the aorta, renal arteries, and renal parenchyma. RESULTS: All mean aortic enhancement was slightly higher with iodixanol than ioversol, measured at three different levels (celiac trunk 315 Hounsfield units [HU] versus 300 HU, renal arteries 325 HU versus 312 HU, aortic bifurcation 276 HU versus 266 HU). However, none of them were statistically significant (e.g., P = 0.26 at the celiac trunk level). Similar results were observed in renal artery and parenchyma enhancements. CONCLUSIONS: Iodixanol and ioversol had similar enhancement characteristics in the early arterial phase. Both substances were well tolerated and seem to be well suited for spiral CTA.

Adult↗
PubMed1998

[Mycotic aneurysm in endocarditis lenta as the etiology of intraparenchymatous cerebral hemorrhage].

CASE REPORT: A 49-year-old male was admitted for left-side headache and mild speech defect. Clinical examination showed a pansystolic murmur of mitral regurgitation and mild Wernicke aphasia. In laboratory studies ESR and CRP were increased. Computed tomography of brain revealed a left temporoparietal hematoma. Echocardiographic examination demonstrated vegetations and mitral valve perforation. In blood cultures grew alpha-streptococci. Cerebral angiography was performed and a fusiform aneurysm on a distal branch of the left middle cerebral artery was identified. Follow-up angiography showed a total resolution of the aneurysm after 6 weeks of intravenous antibiotics. CONCLUSION: This case demonstrate that patients with intracerebral hematomas associated with infectious endocarditis should be investigated for mycotic intracranial aneurysm.

Aneurysm, Infected↗
PubMed1998

Somatosensory evoked potentials: a simple neurophysiological monitoring technique in supra-aortal balloon test occlusions.

The aim of this study was to evaluate somatosensory evoked potentials (SEP) as a simple neurophysiological monitoring method in supra-aortal balloon test occlusions (BTO). The 13 patients examined had carcinoma of the larynx (n = 6), nasopharyngeal malignancy (n = 3), sphenoid meningioma (n = 2), mycotic aneurysm (n = 1), and a tumor of the carotid body (n = 1). Transfemoral balloon occlusion of the internal carotid artery was maintained for 30 min and monitored both clinically and by SEP. None of the 13 patients showed neurological deficits or pathological changes in the SEP. No thromboembolic complications occurred during BTO. In 11 cases the cervical vessels could be spared or reconstructed during surgery. No neurological symptoms occurred during the clinical follow-up. One patient died the day after BTO due to cardiac arrest. Neurophysiological monitoring of preoperative BTO using SEP is a technically simple method. A similar method has been shown to have a high sensitivity and reliability in carotid surgery.

Adolescent↗
PubMed1998

Influence of the hepatobiliary contrast agent mangafodipir trisodium (MN-DPDP) on the imaging properties of abdominal organs.

To assess the influence of Mangafodipir Trisodium on the imaging properties of abdominal organs when using T1-weighted gradient-echo (GE) and T2-weighted turbo spin-echo (TSE) sequences, thirty patients with focal lesions in the liver were examined at a field strength of 1.5 T before and after intravenous administration of Mangafodipir Trisodium (dose: 5 micromol/kg of body weight). Administration of Mangafodipir Trisodium led to a significant increase in the signal intensity of the liver tissue (p < 0.001), the spleen (p < 0.01), the pancreas (p < 0.001), and the kidneys (p < 0.001) in the T1-weighted GE sequence, while there was no relevant enhancement in fatty tissue and the musculature. In the T2-weighted turbo spin-echo sequence, there was no relevant change in the signal following administration of a contrast agent. The contrast-to-noise ratio (C/N) between the lesions and the liver tissue increased significantly in the post-contrast T1-weighted GE sequence (p < 0.001), while there was no change in the contrast-to-noise ratio in the post-contrast T2-weighted turbo spin-echo sequence. The contrast-to-noise ratio of the plain T2-weighted TSE sequence was significantly higher than that in the post-contrast T1-weighted GE sequence (p < 0.001). Although Mangafodipir Trisodium was primarily developed as a hepatobiliary contrast agent for demonstration and differentiation of liver lesions, it also affects the signal levels in the pancreas, spleen, and kidneys in the T1-weighted image. Awareness of this effect on the extrahepatic tissue makes it easier to interpret pathological findings in magnetic resonance imaging (MRI) of the abdomen.

Abdomen↗
PubMed1998

[Direct-current treatment of chemically induced mammary carcinoma in an animal model: MR volumetric assessment of the effect of the therapy].

PURPOSE: To investigate the effect of direct current treatment (DCT) on the growth of mammary carcinomas in rats by MR-volumetry. METHODS: Chemically induced mammary adenocarcinomas in a control group (n = 17) were compared with treated tumours (18 C/cm3 in group A: n = 7 or 36 C/cm3 in group B: n = 12). 31 untreated tumours were situated near a treated tumour (group C). Experiments were carried out using one positive electrode in the tumour centre and three negative electrodes in the periphery. The tumour volume was measured by MRI before, and 1, 3, 6, 9 and 12 weeks after treatment. RESULTS: 12 weeks after DCT, the mean tumour volume in group A (164% +/- 158%, p < 0.05) and group B (13% +/- 24%, p < 0.001) was significantly reduced compared to the control group (434% +/- 230, Mann-Whitney U-Test). Complete tumour regression occurred in 42% of tumours in group B and was not achieved in group A, C and control group. Tumour growth in group C was decreased compared to the control group. CONCLUSIONS: The effectiveness of DCT was found to depend on the applied dosage -36 C/cm3 was more effective than 18 C/cm3. The effect of DCT is not limited to the area between the electrodes.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

[Complications of CT guided lumbar sympathectomy: our own experiences and literature review].

AIM: To review the complications of CT guided lumbar sympathicolysis (CTLS) on the basis of our own experience and the available literature. METHODS: 241 CTLS were performed by a standard technique according to Haaga's method. Clinical follow-up revealed 4 serious complications; these were analysed and compared with published cases. RESULTS: Amongst our patients there were three fibrotic ureter stenoses and one retroperitoneal abscess. Analysis of the serious complications described in the literature indicates that introduction of CT guided lumbar sympathicolysis has reduced the severity and frequency of complications as compared with surgical and "blind" procedures. With CTLS, no deaths due to the procedure have been reported in the literature. The results indicate that damage to the ureters can be caused by substances used for the neurolysis. CONCLUSION: Provided certain safeguards are obeyed, CTLS is a very save treatment. However damage to the ureter may follow even when the procedure was technically satisfactory. Therefore, sonographic control of the kidneys after three months is recommended.

Abscess↗
PubMed1998

[Endorectal MRI and ultrasonography in rectal tumors: correlation with histological staging].

PURPOSE: To compare the accuracy of high resolution endorectal magnetic resonance imaging (EMRI) and endorectal ultrasound (EUS) in the preoperative diagnostic of rectal tumours. PATIENTS AND METHODS: Twenty-one patients with known rectal tumours underwent MR imaging with an endorectal surface coil and EUS. Transversal EMR images were obtained using fast T2-weighted sequences and pre- and postcontrast T1-weighted images. EUS was performed using a 7.0 MHz transducer. Results of both methods were compared with specimens from the resected tumours. RESULTS: Rectal wall layers were reliably demonstrated with both methods in all patients. EMRI and EUS determined the depth of rectal wall invasion. EMRI and EUS agreed with pathologic findings in 16/21 cases, respectively. In one case each, both methods understaged one tumour. EMRI overstaged an adenoma as a T2-tumour. In three and four patients, respectively, no staging was possible due to technical problems. CONCLUSION: EMRI and EUS show comparable results in the preoperative T-staging of rectal tumours. Both techniques are not suitable for differentiating benign from malignant lymph nodes accurately. While EMRI is expensive and technically demanding, it allows an objective documentation of pathological findings which is less dependent on the examiner. Two important clinical conclusions can be drawn from the good results of T-staging: Adenomas and T1-tumours can be treated by local excision. In patients with advanced tumours (T3/T4) a neoadjuvant therapy can be initiated.

Adenoma↗
PubMed1998

Proton MR spectroscopy in infants with cerebral energy deficiency due to hypoxia and metabolic disorders.

PURPOSE: To investigate the similarities and differences of cellular energy deficiencies due to asphyxia and to impaired oxidative phosphorylation caused by enzyme deficiencies using localized 1H-MR spectroscopy of the brain. MATERIAL AND METHODS: In 35 neonates and infants with a postconceptional age of 36.4-153 weeks, 1H-MR spectra were obtained from the basal ganglia. Of the 35 children, 14 served as a control group, 12 suffered from hypoxic-ischemic disease (HIE), and 9 had congenital enzymatic disorders. RESULTS: Eleven of the 12 children with HIE showed low N-acetyl aspartate (NAA) to trimethylamine (TMA) ratios, indicating neuronal damage. Lactate (Lac) to TMA ratios correlated with the HIE grade. Children with congenital disorders of energy metabolism had NAA/TMA ratios ranging from severely decreased to normal, but 7 of the 9 had high Lac signals, even in brains with normal NAA/TMA. CONCLUSION: High Lac/TMA even with normal NAA/TMA in children with enzyme deficiencies, in contrast to Lac/TMA that correlates with clinical grade and low NAA/TMA in asphyxic children, hints at different mechanisms of cell damage in the two disease groups.

Aspartic Acid↗