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H Kugel

Publications and source records attributed to H Kugel.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Proton-MR spectroscopy of the spinal bone marrow. An analysis of physiological signal behavior].

BACKGROUND: Magnetic resonance imaging has shown to be a sensitive method for diagnostics of the red bone marrow, the composition of which changes physiologically and during pathological processes. However, the interpretation of MRI in patients with disorders of the red bone marrow is very difficult. The aim of this study was the characterization of the proton spectrum of healthy bone marrow and its age- and sex-dependent changes to obtain a data basis for measurements in patients. METHODS: 154 healthy volunteers have been examined. After imaging, a spectroscopic measurement was performed to determine the relative intensities of fat and water, and their respective T2 times. RESULTS: While T2 (water: 46.9 ms and fat: 75.4 ms) does not depend on age or sex, the relative signal intensity of fat increases by about 6% per decade. In the age groups between 31 and 50 years it diverges significantly between men (43.5%) and woman (32.5%) (p < or = 0.01, Mann-Whitney-Test. CONCLUSIONS: Proton spectroscopy can increase the reliability of diagnosis by offering information on composition of the marrow. The analysis of spectroscopic measurements requires exact knowledge about normal physiological values.

Adolescent↗
PubMed2000

[MRI-controlled preoperative wire marking of uncertain breast lesions].

PURPOSE: Small suspicious breast lesions that are only visible at MR imaging were preoperatively marked with a hook wire under MR-guidance to allow the removal of the lesion with tissue-sparing surgery. METHOD: In all patients the suspicious lesions were marked preoperatively under MR guidance with a hook wire using a commercially available stereotactic device. Interventions were performed with MR guidance on a 1.0 T and on a 1.5 T system. RESULTS: In 19 patients 22 lesions were localized. One lesion was missed and removed in a second procedure. The mean duration for localization was 66 +/- 20 min (range 38-119 min). In two patients two lesions were localized. The mean deviation of the wire tip to the lesion was 2.0 +/- 2.6 mm. In this series, 6 of 22 lesions were malignant. The mean diameter of the lesion was 7.6 +/- 2.6 mm (range 3-14 mm). CONCLUSION: Suspicious breast lesions detectable only in MR imaging can be accurately localized with a hook wire preoperatively under MR control to remove the lesion with a tissue-saving surgery.

Adult↗
PubMed2000

[Precision of MRI-guided needle placement--experimental results].

PURPOSE: To estimate the accuracy of the determination of tip position of MR compatible biopsy needles based on signal voids and artifacts in MR guided biopsies. METHOD: In a nylon grid phantom an MR compatible 18G needle (E-Z-EM) was measured in a 1.0 T imager using TSE- and FFE-sequences of 20 s and 40 s duration in 34 different orientations of needle versus B0, frequency and slice selection gradient. 4 radiologists with no experience in the evaluation of signal void artifacts estimated the needle tip positions from needle tip artifacts. The readers determined the needle tip before and after a 15 minute training session based on high resolution images with explanation of size and shape of specific artifacts of biopsy needles in 12 different orthogonal or parallel orientations to B0 and frequency encoding gradient that are possible if the needle lies parallel to the slice, i.e. orthogonal to the slice selection gradient. The values obtained before and after the training session were compared to the real position of the needle tip. RESULTS: Mean distance of actual needle tip and tip position as determined from images was 1.8 +/- 2.3 mm in TSE-versus 2.5 +/- 1.2 mm in FFE-images, with the needle length overestimated. After a 15 minute training session the positioning error decreased significantly to 0.2 +/- 1.8 mm for TSE-sequences and to 1.0 +/- 1.8 mm for FFE-sequences. A higher accuracy of tip localization was obtained with TSE sequences. CONCLUSION: In MR guided biopsies using FFE- and TSE-sequences the needle position can be more accurately determined if the reader is familiar with the 12 orthogonal or parallel positions of the needle with respect to B0 and frequency encoding gradient and the corresponding artifacts.

Artifacts↗
PubMed2000

Non-invasive determination of metabolite concentrations in human transplanted kidney in vivo by 31P MR spectroscopy.

PURPOSE: To investigate concentrations of phosphorus-containing metabolites in human transplanted kidney in vivo by quantitative 31P MR spectroscopy (MRS) using surface coils and to compare the obtained values with previous data. MATERIAL AND METHODS: In 5 patients with well-functioning transplanted kidneys, 31P spectra were obtained with the three-dimensional localization image-selected in vivo spectroscopy technique applying a protocol for quantitative spectroscopy using surface coils. Relaxation corrected signal intensities determined by time domain fitting were used to derive absolute molar concentrations for phosphate-containing metabolites. RESULTS: Little or no phosphocreatine in all spectra verified the absence of muscle contamination, confirming proper volume localization. The mean concentrations in the transplanted kidneys were as follows: ATP 1.60 +/- 0.26 mmol/ 1, PDE 2.14 +/- 0.91 mmol/l, Pi 0.66 +/- 0.25 mmol/l, PME 2.32+ /- 0.50 mmol/l. These values are consistent with previously reported values determined by other techniques. CONCLUSION: The non-invasive determination of absolute metabolite concentrations in human kidney using MRS supplements the use of signal intensity ratios to detect pathologic changes in the energy metabolism of transplanted kidneys.

Adenosine Triphosphate↗
PubMed2000

Results of electrochemical therapy of colorectal liver metastases in rats followed up by MRI.

RATIONALE AND OBJECTIVES: Direct-current or electrochemical therapy is an alternative method for local tumor therapy. Until recently, it was mainly applied in China and was relatively unknown in the Western world. This study examines the feasibility and effectiveness of applying direct-current therapy in liver metastases of colorectal carcinomas in an animal model. METHODS: Liver metastases were implanted in 47 BDIX rats by subcapsular injection of cells from a colorectal strain (DHD/K12). The success rate of implantation and the size of the tumors were determined after 3 weeks by MR imaging (T2-weighted turbo spin-echo images; relaxation time 1,800 ms, echo time 80 ms). The direct-current therapy was applied by one platinum electrode placed in the center of the tumor and four at the periphery of the tumor. Suitable therapy parameters were established in a pilot study by comparing four different methods of direct-current therapy with a control group. The methods varied with respect to the electrode polarity and the applied voltage. In a second series of investigations, tumor growth was monitored by MR imaging 3 and 5 weeks after therapy. RESULTS: The tumor implantation rate was 92.6% at a tumor cell concentration of 8 x 10(5)/mL. The most effective therapy method was achieved by placing an anode at the center of the tumor and four cathodes at the periphery, with an applied charge of 80 C/cm3. Complete tumor necrosis was observed in 54% of cases. In the follow-up measurements, the mean tumor diameter was 0.65 cm at 3 weeks after therapy and 0.76 cm at 5 weeks after therapy. In comparison with the control group (1.08 and 1.53 cm, respectively), this represented a significant reduction in tumor growth rate. CONCLUSIONS: This study is the first to demonstrate an antitumoral effect of direct-current therapy on liver metastases of colorectal cancer in rats.

Animals↗
PubMed2000

Late resolution of diffusion-weighted MRI changes in a patient with prolonged reversible ischemic neurological deficit after thrombolytic therapy.

BACKGROUND: Reduced apparent diffusion coefficients (ADCs) correlate with cerebral ischemia. The combination of ADC with techniques to measure cerebral perfusion may help to assess the effect of treatment. CASE DESCRIPTION: The authors describe a patient who experienced an acute stroke with hemianopia, consequently treated with intravenous recombinant tissue plasminogen activator. Positron emission tomographic imaging and MRI, including diffusion-weighted MRI, were performed during and shortly after treatment with recombinant tissue plasminogen activator and 34 to 35 hours later. Cerebral perfusion of the left occipital region was reduced to 74%. Diffusion-weighted MRI detected a territory of restricted water movement in the corresponding area. Further magnetic resonance sequences did not show any pathologies. In follow-up, positron emission tomography demonstrated reperfusion. The volume of diffusion and ADC abnormalities detected by MRI decreased markedly. A few hours later, the patient recovered completely. A third MRI examination 10 days later showed normal findings. CONCLUSIONS: In a patient with prolonged reversible ischemic neurological deficit, resolution of early diffusion changes corresponded to cerebral reperfusion and to the recovery of clinical symptoms.

Acute Disease↗
PubMed2000

MRA in patients with cerebrovascular disease. Considerations of clinical effectiveness.

OBJECTIVE: To establish in which clinical contexts cerebral MR angiography (MRA) is routinely carried out in a neurological university department and to describe its clinical impact. MATERIAL AND METHODS: Medical records, reports of findings and documentation of imaging examinations carried out in all 69 patients referred to the Department of Radiology from the Department of Neurology between 1995 and 1998 for cerebral MRA were evaluated. The clinical impact of all imaging findings was assessed on the basis of the medical records. RESULTS: Circulatory disturbances in the vertebrobasilar arteries (n = 34) were the most frequent indication for investigation. MRA followed CT or duplex sonography in 66 of the 69 patients with a mean delay of 8 days. MRA was considered diagnostically inferior to conventional MR in 11 cases, comparable in 30 and superior in 25. Comparing MRA and duplex sonography, the corresponding figures were 12, 29 and 23. In retrospect, 56 MRAs were judged unnecessary. CONCLUSION: Controlled clinical studies on optimal use of MRA are needed to avoid wasting resources and to exploit the method's full diagnostic potential in appropriate cases.

Adult↗
PubMed1999

MR cholangiography in children with autosomal recessive polycystic kidney disease.

BACKGROUND: Magnetic resonance cholangiography (MRC) is a relatively new, non-invasive imaging technique of the biliary tree that has shown good correlation with endoscopic retrograde cholangiopancreatography. The liver manifestation of autosomal recessive polycystic kidney disease (ARPKD) is congenital hepatic fibrosis (CHF). CHF may be accompanied by Caroli's disease, which is characterised by a non-obstructive dilation of the intrahepatic bile ducts. OBJECTIVE: A prospective study was conducted to determine the presence and extent of Caroli's disease in children with ARPKD. MATERIALS AND METHODS: Seven children with ARPKD aged from 3.0 to 10. 1 years were examined. CHF was confirmed in all biopsied cases (5 of 7). All children had been followed by repeated abdominal US examinations for many years. The MR examination included a morphological imaging study using a T2-weighted turbo spin-echo sequence and a heavily T2-weighted inversion-recovery turbo spin-echo sequence with three-dimensional maximum intensity projection (MIP) reconstructions for MRC. RESULTS: The diagnosis of Caroli's disease could be made in one case by US; in two other children Caroli's disease was suspected, but the differentiation from hepatic cysts was not possible. By MRC, Caroli's disease could be diagnosed in three of seven children. Furthermore, MRC with MIP reconstructions demonstrated the extent of the disease by showing the entire biliary tree from different angles. CONCLUSIONS: MRC is a valuable method to establish the diagnosis and demonstrate the extent of Caroli's disease.

Bile Ducts, Intrahepatic↗
PubMed1999

Magnetic resonance sialography.

To evaluate a new noninvasive sialographic technique, we applied a new magnetic resonance technique to 10 healthy volunteers and 21 patients with lesions of the parotid gland. In addition to the usually performed T(1) and T(2) cross-sectional sequences, a heavily T(2)-weighted sequence (TR = 3600 msec, TE = 800 msec) was performed that allowed depiction of the fluid-filled parotid duct system. Twenty-one patients with benign as well as malignant parotid gland pathologies were examined: sialadenitis (n = 6), sicca syndrome (n = 2), pleomorphic adenoma (n = 4), carcinoma of the parotid gland (n = 2), lymphoepithelial carcinoma (n = 1), cystadenolymphoma (n = 3), non-Hodgkin's lymphoma (n = 2), and congenital duct dilatation (n = 1). Stenseńs duct was reliably depicted in all volunteers and patients. The primary branching ducts were reliably depicted in all normal cases. Intraglandular and extraglandular duct dilatations and duct strictures were well depicted in patients with chronic sialadenitis. Sialolithiasis with a calculus obstructing the duct was demonstrated in 2 cases. In conclusion, Initial experience indicates that magnetic resonance sialography can be applied successfully to investigate the duct system of the parotid gland. The usually performed cross-sectional MRI (T(1)- and T(2)-weighted images, gadolinium-DTPA) depicts the internal architecture of the parotid gland with high reliability. Magnetic resonance sialography with heavily T(2)-weighted images adds important information about the ductal system. Because it is completely noninvasive, the only contraindications are the ones generally accepted for MRI.

Adult↗
PubMed1999

[MR-compatible and conventional marker wires in breast diagnosis--experimental studies on their dislocatability and artifact size in MRT].

PURPOSE: Localization of non-palpable suspicious breast lesions with tumor localization wires is commonly used before surgical excision. Dislocation of the wire is possible. The possibility of dislocation for different types of tumor localization wires was examined experimentally. METHODS: 22 different tumor localization wires were inserted into the subcutaneous fat-tissue of a pig. The wire tip was recorded under fluoroscopy. Traction was applied to the wire using a spring-balance. The artifact size of MR-compatible wires was examined in a 1.0 Tesla MR imager. RESULTS: The localization wires with an X-configuration and long hook could not be dislocated by a force up to the maximum of 12 Newton. The retractable localization wires were easily dislocated at traction forces of 1 Newton. Other wires with only one hook could withstand a traction from 2 up to 7 Newton. The wires with a Z-configuration and wires with short hooks showed a highly variable rate of resistance. The artifact size of localization systems was between 10.1 and 11.0 mm for gradient-echo sequences and between 6.7 and 7.1 mm for spin-echo sequences. CONCLUSION: Tumor localization wires with an X-configuration and long hooks were best anchored in the tissue. The advantage of repositioning retractable wires is confined by the high risk of accidental dislocation. No reliable fixation in the tissue could be achieved using wires with a Z-configuration and wires with short hooks. MR-compatible wires were comparable to non-MR-compatible wires concerning the rate of resistance. The size of the artifacts of MR-compatible systems showed no relevant differences.

Adipose Tissue↗
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

[Correlation of MRI and histopathological findings in inflammatory skin diseases].

PURPOSE: Can spatial and contrast resolution be achieved with currently available MR devices for the successful assessment of inflammatory diseases of the skin? METHOD: High resolution MRI was performed in 20 patients with non-malignant diseases of the dermis and subcutis. The skin biopsies subsequent to the MR examinations were indicated for clinical reasons. The MR examinations were done in the location of later performed skin biopsies using a 1.0 Tesla system (Gyroscan T10 NT, Philips, Best, the Netherlands) and a surface coil of 7.5 cm inner diameter. Conventional spin-echo (SE-Sequenz)- and gradient-echo (GRE)-sequences were optimised to obtain maximum spatial resolution with a sufficient signal-to-noise ratio within a tolerable examination time. MR visualisation of histopathology was assessed by four readers using a questionnaire. RESULTS: In 15 of 20 cases, high resolution MRI allowed a correct classification of the visualised dermal and subcutaneous patterns, in accordance with the histological work-up of the corresponding specimen. Due to the still only suboptimal spatial and contrast resolution the structure of the epidermis could not be assessed adequately. Determination of contrast enhancement or non-enhancement after administration of intravenous contrast agent provided information on the degree of tissue perfusion in 19 patients, which complemented the morphological assessment. CONCLUSION: High resolution MRI allows to identify non-invasively histological main patterns of inflammatory skin diseases. However, final diagnosis often depends on higher microscopic resolution and special staining.

Adolescent↗
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

High-resolution MR imaging of the cutis and subcutis. Histological correlation.

OBJECTIVE: To determine whether the spatial resolution that can be achieved with currently available MR devices is adequate for the evaluation of skin disease. MATERIAL AND METHODS: We correlated high-resolution MR images of the skin with dermatohistopathology in 26 patients. The examinations were carried out on a 1.0 T imager using a commercially available surface coil (ID 7.5 cm) and optimized SE and GE sequences. Image quality was assessed by four readers on a questionnaire. RESULTS: The visualization of the dermis, subcutaneous tissue, and muscle fascia allowed a pattern analysis that gave findings identical to those at dermatohistopathology. It was possible to distinguish septal from lobular panniculitis, and lipatrophia from sclerodermia. Images with contrast media infusion were useful in the differential diagnosis. CONCLUSION: High-resolution MR imaging may narrow down the differential diagnosis of various skin diseases and may help to reduce the number of skin biopsies on certain indications.

Adolescent↗
PubMed1998

Detection of focal hepatic lesions: effects of superparamagnetic iron oxide (AMI-25) on magnetic resonance imaging of the liver using T2-weighted fast spin-echo sequences and gradient-and-spin-echo sequences at 1.0 tesla.

RATIONALE AND OBJECTIVES: The authors evaluate the value of two fast spin-echo sequences (FSE) with different T2-weighting (repetition time [TR]/echo time [TE] = 2000/90 mseconds and TR/TE = 2000/40 mseconds) and combined gradient-and-spin-echo sequences (TR/TE = 2000/90 mseconds) for contrast-enhanced liver imaging with superparamagnetic iron oxide (AMI-25). METHODS: Forty-seven patients with focal liver lesions underwent magnetic resonance imaging at 1.0 tesla. AMI-25 was administered intravenously at a dose of 15 micromol iron/kg. RESULTS: Administration of AMI-25 resulted in a significant increase of lesion/liver contrast-to-noise ratio (C/N) for all T2-weighted sequences (P < 0.001). On the precontrast images, the FSE sequence with a TE of 90 mseconds had the highest C/N (16.0 +/- 4.5) whereas the best postcontrast C/N (27.9 +/- 7.6) was obtained with the mild T2-weighted FSE sequence with a TE of 40 mseconds. CONCLUSIONS: Fast spin-echo sequences are valuable sequences for imaging of the liver at 1.0 tesla. For AMI-25-enhanced magnetic resonance imaging, a mild T2-weighted FSE sequence is recommended.

Adult↗