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Biomedical subjects

M Reiser

Publications and source records attributed to M Reiser.

At least 37 records · Page 2Linked to original sources
PubMed1999

[New techniques and pulse sequences in MRI of the liver].

PURPOSE: The MRI techniques which have contributed to increasing utilization of MRI for abdominal imaging are described and recent advances addressed. METHODS: For breath-hold examinations of the abdomen, two basic techniques are required: array coil technology and fast and ultrafast pulse sequences providing T1 and T2 contrast. RESULTS: Circular polarized array coils render high signal-to-noise ratios (SNR) within large imaging volumes. With fast gradient-echo sequences the liver can be scanned with or without fat saturation within one breath-hold. When adequate parameters are selected, T2-weighted fast (turbo) spin-echo sequences allow high contrast between normal liver tissue and focal liver lesions, even if breath-hold acquisition is applied. Moreover, good soft tissue contrast can also be achieved with ultrafast single-shot sequences. Based on this sequence type, MRCP with a 512 matrix could be performed. The "TRUE FISP" allows for high resolution visualisation of vessels without contrast media. Three-dimensional T1-weighted sequences allow for scanning the upper abdomen with a slice thickness of 3 mm within one breath-hold. Diffusion-weighted sequences contribute to the characterisation of focal liver lesions. DISCUSSION: Modern MRI technology including phase-array coils and high-performance gradient systems made it possible to perform all examinations in breath-hold techniques, reducing motion artifacts.

Humans↗
PubMed1999

[MRI-controlled regional hyperthermia].

PURPOSE: Regional hyperthermia in combination with chemotherapy or/and radiotherapy is a promising treatment concept for locally advanced, deep-seated tumors. The purpose of the project is the optimization of the therapy using non-invasive, three-dimensional imaging of tissue changes or of the temperature distribution during regional hyperthermia. METHODS: MRI offers methods suitable in principle for tissue characterization and MR thermometry. A new MRI-hyperthermia hybrid system has been developed based on an innovative hyperthermia applicator and an open MRI system. RESULTS: After successful testing of the new MRI-hyperthermia hybrid system simultaneous MRI and regional hyperthermia in patients could be accomplished for the first time. At present the T1 relaxation time seems to be a promising parameter for MR thermometry. CONCLUSION: The first clinical application of the MRI-hyperthermia hybrid system can be regarded as an important step towards the development of regional hyperthermia. This new hybrid system and the MR thermometry methods have to be investigated prospectively in clinical studies.

Equipment Design↗
PubMed1999

[Percutaneous implantation of port-catheter systems for intraarterial chemotherapy of the liver].

PURPOSE: The objective of this study was to determine the usefulness, safety and acceptance of a new technique of percutaneous implantation of port-catheter-systems (PIPS) for locoregional intraarterial chemotherapy of the liver. MATERIAL AND METHODS: In 50 patients with malignant hepatic disease, 52 percutaneously implantable port-catheter systems were implanted for intraarterial chemotherapy of the liver as an interventional radiological technique. A commercially available angiographic catheter was placed in the hepatic artery under fluoroscopic control via a transfemoral approach and connected to a Port-A-Cath situated in the groin. This procedure was done on an outpatient basis; no medical treatment was administered. RESULTS: Percutaneous placement of the port-catheter system was successful in all cases, also in those with a hepatomesenteric trunk. No peri- and post-interventional complications occurred. The median patency was 312 days (13-547 days). The catheter-related complication rate was 12%. The function could be restored by replacement or an interventional procedure in all but one case (2%). Infection and leakage did not occur. The system had been withdrawn without complications in 7/52 cases for a variety of reasons (e.g. hemihepatectomy, desire of the patient or clinician, dissection after intervention, replacement). CONCLUSION: Percutaneous placement of a port-catheter system is a safe and easy alternative to the surgical placement of port systems for hepatic intraarterial chemotherapy. Long-term complication rates are comparable. The option of easy withdrawal and interventional correction of dysfunction as well as lower costs are additional advantages.

Adult↗
PubMed1999

[Percutaneous interventional radiologic implantation of intravenous port-catheter systems].

PURPOSE: Percutaneous interventional radiologic and surgical techniques of port-catheter implantation are described and compared with regard to the technical procedure and results. MATERIALS AND METHODS: In 53 patients with various malignancies interventional radiologic implantation of port-catheter systems into the subclavian vein was performed to provide long-term intravenous access for chemotherapy. The technical procedure, operation time, complication rates and long-term patency were compared with those of surgically implanted systems. RESULTS: Implantation was successful in all cases. Mean operation time was 36 min (range 20-55 min). Mean function time was 189 days (range 7-518). Primary patency rate was 92.5% with a total complication rate of 15% (8/53). In three patients (5.7%) pneumothorax was observed but did not require further treatment. In two cases (3.8%) local infection occurred, and in one patient (1.8%) a non-complicated wound dehiscence. In 12/53 patients (22.6%) the system was withdrawn. Among these, withdrawal was due to complications in 4/53 (7.6%) cases. CONCLUSIONS: Interventional radiologic implantation of long-term intravenous port-catheter systems is comparable to surgical placement with regard to both complication rate and long-term patency.

Adult↗
PubMed1999

[The diagnosis of stages T1 and T2 in laryngeal carcinoma with multislice spiral CT].

The purpose of the study was to preoperatively investigate small laryngeal carcinomas using multi-slice spiral CT (MSCT) and subsequent multiplanar reconstructions (MPR) and to compare the results to the detailed spread found at surgery and histology. Nine patients with small (T1, T2) laryngeal cancer were investigated on a MSCT scanner (Siemens plus 4 Volume Zoom, Siemens). A 4 x 1 mm collimation, 120 kV, 200 mAs and a 0.5 seconds rotation time were used, allowing a coverage of the entire larynx in approximately 10 seconds within a single breathhold. Multiplanar reconstruction's (MPR) in sagittal and coronal plane were reconstructed in all patients and rated in consensus reading. In 8 of nine patients, the glottic spread was detected by MSCT, in one cause of a supraglottic tumor a glottic invasion was excluded. The infiltration of the anterior commissure, the infiltration into the subglottic space and the extension into the hypopharynx was correctly assessed in all patients. MSCT was not able to predict infiltration of the arythnoids in two patients. The use of multi-slice spiral CT for the preoperative assessment of small laryngeal tumors shows great promise. The detection or exclusion of subtle spread of these tumors into the supra- or subglottic space and along the glottic level was possible with high accuracy. As the examination time is short, artifacts are rare and multiplanar reconstructions gain in clinical importance.

Carcinoma↗
PubMed1999

[Multislice computed tomography of the small intestine. Preliminary results].

SUBJECT: Spiral computer tomography (SCT) became an important supplement to the Sellink examination. Multi slice computer tomography (MSCT) achieves a z-axis resolution of 1-2 mm without considerable increase in the acquisition time. In this paper, examination technique in first clinical results of CT-Sellink examination with MSCT, including the 3D-reconstruction are presented. MATERIALS AND METHODS: The investigations were carried out with the Somatom Plus 4 Volume Zoom (Siemens, Forchheim) scanner. The following parameters were employed: 4 parallel detector ledges, collimation 4 x 1 mm, tube power 140 mA, tube voltage 120 kV, pitch 5 up to 6 mm, slice thickness 1 mm and 2 mm, reconstruction with 50% overlap. Via a duodenal tube, the small intestine was distended by means of 1.5 up to 2.5 l methyl-cellulose suspension. The data were acquired 35 s after injection of 120 ml contrast media (Ultravist). Various methods of postprocessing were applied on a workstation. RESULTS: As of yet, 16 patients were examined with MSCT-Sellink. In 4 cases pathological findings were detected with MSCT-Sellink, which were not recognized with X-ray Sellink. CONCLUSION: Due to high z-axis resolution and short acquisition time, the morphological details of the small intestine can be visualized utilizing MSCT-Sellink. The data set is well suited for 3D postprocessing. Improvement of diagnostic accuracy can be anticipated.

Adult↗
PubMed1999

Assessment of gastric cancer: value of breathhold technique and two-phase spiral CT.

The purpose of this study was to evaluate the capabilities of subsecond spiral CT in detecting and staging of gastric cancer. Our study included 40 patients with endoscopically detected gastric carcinomas. Two-phase spiral CT was performed within one breathhold each. Distension of the stomach was achieved by intravenous application of scopolamine and drinking of 500 ml water. After bolus injection of contrast medium, scanning was performed in the arterial and venous phase. Gastric tumour extention and lymph node involvement was assessed. Gastric cancer was detected in 39 of 40 cases (sensitivity 97.5%). Location of the tumour was correctly assessed in all cases. In 31 of the 39 cases (79.4%) CT staging was accordant with pathological staging. One hundred two (70%) of 145 nodes infiltrated by tumour tissue were detected and 144 (42.8%) of 336 nodes free of metastatic involvement were found. The predictive values of positive and negative results for the detection of lymph node metastases were 67.1 and 75%, respectively. Spiral CT is recommended for staging of gastric cancer.

Adenocarcinoma↗
PubMed1999

Evaluation of spiral CT in staging of colon and rectum carcinoma.

The purpose of our study was to evaluate the capability of a subsecond spiral-CT scanner using two contrast medium phases in staging of colorectal cancer. In our study we included 37 patients with proven rectum or colon carcinoma. Spiral CT was performed following tap-water enema of the colon in the arterial and venous phases of contrast medium enhancement. Our results were compared with the findings of pathological examination after surgery. The tumor's size and extension were evaluated in the arterial and venous phases, the lymph nodes in the venous phase of the CT scan. The tumor was in the rectum (n = 14), sigma (n = 11), descending colon (n = 6), and cecum (n = 6). Two-phase spiral CT had a sensitivity of 97.2% in the arterial phase and 89.1% in the venous phase in detecting the carcinoma. The staging results were in the arterial phase in 30 of 37 cases (81.0%) and in the venous phase in 24 of 37 cases (64.8%) according to pathology. In 27 of 32 patients (84.3%) lymph nodes were detected. The correct classification of the N-stage was possible in 23 of 34 cases (67.6%). The combined use of arterial and venous phases in staging of colorectal cancer can improve the T- and N-stage classification in comparison with using only one contrast medium phase. The arterial phase is superior compared with the venous phase for local tumor staging and the venous phase is used for lymph node assessment.

Adult↗
PubMed1999

Diffuse metastatic infiltration of a carcinoma into skeletal muscle.

Skeletal muscle is one of the most unusual sites of metastasis from any malignancy. We report a patient with rapidly progressive contractures due to metastatic infiltration of a carcinoma of unknown origin into the skeletal muscle. This 61-year-old man presented with a 1-month history of rapidly evolving, painful restriction of mobility of his right arm and his legs. Computed tomography showed diffuse metastatic nodules in all muscles, particularly in the hip abductors. Muscle biopsy revealed extensive infiltration of the muscle with carcinoma cells.

Biopsy↗
PubMed1999

MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome.

A 40-year-old white man presented with fever, muscle pain, skin nodules and persistent hypereosinophilia over a period of 1 year. In addition, he had ventricular arrhythmias with episodes of tachycardia. Besides a lack of response to antiparasitic therapy, laboratory and pathological data excluded the diagnosis of trichinosis or any other parasitic infection. The patient's course of the disease over the previous 1(1)/2 years was compatible with hypereosinophilic syndrome. In a muscle biopsy several eosinophilic perivascular and leucocytic intravascular infiltrates were found, indicative of muscle involvement by the disease. This is a report on the MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome.

Adult↗
PubMed1999

Metastases to the breast from rhabdomyosarcoma: appearances on MRI.

The authors report a case of blood-borne bilateral metastatic breast disease of alveolar rhabdomyosarcoma (RMS) in a 21-year-old patient. The possibilities of mammography, ultrasound, and MRI in the early detection of breast metastases and their appearance on these modalities are discussed. Whereas mammography rendered no additional information due to dense breast parenchyma and ultrasound showed only a solitary tumor without definite criteria of malignancy, multifocal bilateral spread was verified with MRI and early ring-like enhancement suggested malignancy. Therefore, we conclude that MRI may provide useful information in evaluating patients with sarcomas, even when there is no clinical evidence for metastatic disease of the breast.

Adult↗
PubMed1999

Magnetic resonance imaging of lateral epicondylitis of the elbow with a 0.2-T dedicated system.

The purpose of this study was to evaluate MR imaging findings of the common extensor tendon in patients with lateral epicondylitis and asymptomatic volunteers studied on a 0.2-T dedicated system. In 23 patients (age range 29-58 years, mean age 47 years) with clinical symptoms of lateral epicondylitis MR imaging was performed using T1-, T2- and contrast-enhanced T1-weighted spin-echo sequences. In addition, the elbows of seven healthy volunteers (age range 22-29 years, mean age 25 years) and the symptom-free contralateral elbow of 11 of the 23 patients (age range 29-58 years, mean age 47 years) were studied as controls. Five patients were surgically treated after the MR examination and the results of histopathology were correlated with MR findings. Of the patients, 95.6 % showed intratendinous signal intensity changes on T1-weighted images on the symptomatic side. In 69.6 % signal alterations were observed on T2-weighted sequences and in 56.5 % an intratendinous contrast enhancement was present. Histopathology showed fibrovascular proliferation and fatty degeneration in patients with distinct signal intensity changes and contrast enhancement. Patients with only minor signal intensity changes on T1- and T2-weighted sequences and no contrast enhancement demonstrated fibrosclerotic degeneration and intratendinous cartilage formation in histopathology. The contralateral elbow showed signal intensity changes in 6 of 11 (54.5 %) cases on T1-weighted images and in 3 of 11 (27.3 %) on T2-weighted images. In the group of healthy volunteers minor signal intensity changes of the common extensor tendon could be seen in only 1 case. In patients with lateral epicondylitis of the elbow the type and extent of pathologic changes within the common extensor tendon can be evaluated using a dedicated low-field MR system. On the basis of MR imaging findings a more specified therapy planning among the variety of treatment modalities can be achieved.

Adult↗
PubMed1999

Echo-planar magnetic resonance imaging (EPI) with high-resolution matrix in intra-axial brain tumors.

The aim of this study was to assess the potential of high-speed interleaved echo-planar imaging (EPI) to achieve diagnostic image quality comparable to T2-weighted imaging in patients with brain tumors. Seventeen patients with intra-axial, supratentorial tumors (10 untreated gliomas, 7 radiated gliomas) were investigated on a 1. 5-T scanner. The conventional scan (SE, TR/TE = 2200/80 ms, 18 slices) was acquired in 8 min, 4 s, and EPI (TR/TE = 3000/80 ms, 18 slices) was completed in 25 s. The films were compared in a blinded trail by three radiologists. On the general impression and anatomic display, both sequences were rated to be of similar quality. Artifacts were slightly more pronounced at the skull base and around surgical clips using EPI. Tumor delineation was nearly equivalent using EPI, compared with the T2-weighted sequence. Echo-planar imaging reached diagnostic quality in all patients. Interleaved high-resolution EPI yielded sufficient quality to depict intra-axial, supratentorial brain tumors. Since EPI can be obtained in a small fraction of the time needed for conventional spin echo, in addition to other indications it could be considered to study patients unable to cooperate.

Artifacts↗
PubMed1999

Speech processing in radiology.

The goal of this study was to evaluate the recognition rate, learning potential and amount of time needed to complete a report with the Philips speech recognition system SP 6000 (Philips, Best, The Netherlands). Four radiologists dictated reports of interventional radiology, MRI examinations of the musculoskeletal system and CT examinations of the thorax and abdomen with the Philips system using the German language. The recognition rate of each report and improvement rate after each learning phase of the Philips system was assessed. The time needed to complete a report using the Philips system was then compared with the time needed to complete a report using the tape-based system via a time analysis. The average recognition rate for the four radiologists using the Philips system was 79.6 %, which improved to 92.5 % after the third adaptation. Initially, the average time demand to dictate and correct one report was approximately 16.8 min, but this time decreased to 8.1 min after the third adaptation. In contrast, only 3. 6 min were needed to dictate and correct one report using the tape-based system. However, with the speech recognition system, dictation, correction and transcription of the report can be completed within 15 min, whereas with the tape-based system, it takes nearly 1 day. With the Philips system, speech recognition can reach as high as 95 % since each adaptation of the system improves the recognition rate by approximately 5 %. While the Philips system is associated with longer dictation times than the tape-based system, turn-around time for a complete report is substantially shorter with the Philips system than the tape-based system.

Computer Communication Networks↗
PubMed1999

Symptomatic fibrous lunato-triquetral coalition.

In general, carpal coalitions are considered to be asymptomatic. Incomplete separated joints and associated changes similar to osteoarthritis and pseudoarthrosis are known as possible causes of wrist pain. We present the clinical history, plain-film, and MR imaging findings of two patients with symptomatic fibrous lunato-triquetral coalition. Conventional films disclosed a narrowed space between the lunate and triquetral bone with cysts and sclerosis similar to pseudoarthrosis. Magnetic resonance imaging showed bone marrow edema adjacent to the incomplete separated lunato-triquetral joint and Gd-DTPA enhancing fibrovascular tissue in the synovium and subarticular cysts, explaining the pain over the ulnar-sided wrist. Patients with congenital lunato-triquetral coalition may poorly tolerate stress loading or trauma, resulting in a symptomatic state similar to degenerative arthritis or pseudoarthrosis, which is demonstrated by enhanced MR imaging.

Adult↗
PubMed1999

Misleading diagnosis of retroperitoneal actinomycosis.

A 34-year-old woman presented with a left-sided suprarenal space-occupying lesion on sonography. Culture of material obtained during sonographic-guided puncture of the retroperitoneal lesion yielded a mixed flora of Actinomyces and Peptostreptococcus. Initially, a misleading diagnosis of an adrenal pheochromocytoma was initiated by highly positive metaiodobenzylguanidine scintigraphy after chemical chemistry vanillylmandelic acid (VMA) test showed elevated values for adrenaline and its derivatives. Retroperitoneal actinomycosis with yet unproven spread into thoracic and cervical compartments is a particular unusual presentation of an infection with these organisms. Because it may mimic subacute infections or malignant masses in terms of clinical and laboratory findings, radiological diagnosis of this entity may be difficult. The diagnosis was based on results of culture and the response of the patient to long-term penicillin-derivate therapy after surgical drainage of the suprarenal abscess formation.

3-Iodobenzylguanidine↗
PubMed1999

MR findings in a patient with Kernicterus.

We report on a 2.5-year-old boy with severe mental retardation, choreoathetosis, dystonia, muscle rigidity, opisthotonus and severe hearing impairment. He had history of severe hyperbilirubinaemia immediately after birth presumably due to ABO incompatibility. The history and the clinical picture suggested the diagnosis of Kernicterus. The MR imaging examination upon admission revealed bilateral signal intensity increase in the globus pallidum on T2-weighted sequences. Additionally, our patient showed signal intensity changes within the subthalamic nuclei, which is known to be another characteristic area of bilirubin deposition in Kernicterus.

Abnormalities, Multiple↗