Biomedical subjects

M Reiser

Publications and source records attributed to M Reiser.

At least 19 recordsLinked to original sources

PubMed2003

[Diagnostic evaluation of pancreatic carcinoma prompting treatment decisions].

An early diagnosis or even sufficient screening tools may allow improved and/or more successful treatment strategies for pancreatic carcinomas. Presently,we have no useful screening tools available. The 5 year survival rates of those suffering from pancreatic cancer is around 3%, with only 15% of patients at diagnosis available for curative resection protocols. Thus, better diagnostic procedures for populations at risk are urgently required. Today,endosonography complements new CT and MRI tests. High resolution CT and contrast enhanced MRI procedures are rapidly evolving and may offer more precise diagnostic opportunities. PET tests help discriminating benign from neoplastic tumors, and new molecular markers may offer the opportunity to screen patients at risk with the hope for an early diagnosis. Nevertheless, the technical progress made in tomographic procedures is developing so rapidly that comparative studies are often outdated at publication. Therefore,we have reason to hope for improved diagnostic skills, but presently have only limited data for the new techniques currently available.

Biomarkers, Tumor↗

PubMed2003

[Visualization of radiographically occult osteochondrosis dissecans of the talus using MRI].

Posttraumatic disorders of the ankle are a common cause of chronic pain. Magnetic resonance imaging (MRI) has proved to be highly useful in clarifying a wide spectrum of underlying lesions which frequently cannot be detected on radiographs. Even if the assessment of the lateral collateral ligaments of the ankle is not regarded as a primary indication for MRI, it allows the diagnosis of subchondral contusions or cysts, anterolateral impingement syndrome, sinus tarsi syndrome, osteochondral fractures and osteochondrosis dissecans of the talus (ODT),which may not be detected with other imaging modalities. A 42 year old female patient suffered from persisting non-specific pain following an inversion trauma 4 months previously. MRI enabled the detection of an ODT which was not diagnosed on plain radiographs and which was verified upon arthroscopy. A superficial cartilage defect, as shown arthroscopically,was not delineated using MRI. Our observations indicate that MRI may be useful in patients with unclear persisting pain following ankle trauma and that it may contribute to the early detection of lesions which require surgical intervention.

Adult↗

PubMed2003

[Computed tomography in the diagnosis of inflammatory bowel disease -- methodology of MSCT and clinical results].

PURPOSE: This paper discusses the diagnostic yield of multislice computed tomography (MSCT) in inflammatory bowel disease. METHODS: Contrast media are administered intraluminally (colon, small intestine) and intravenously (triple contrast CT). Filling of small bowel is achieved by means of jejunal tube ("Sellink CT") or via the oral route. Pharmacological relaxation of the intestine decreases motion artifact. Intraluminal contrast media consist of either hyperdense, "positive" or hypodense, "negative" liquids. RESULTS: Thin-slice MSCT of the entire abdomen allows high-quality post processing (MPR, thin-slice MIP). Due to superior distension, Sellink CT improves estimation of stenosis or changes in thickness and contrast of bowel wall. Positive contrast is superior in the detection and preoperative localization of abscess, fistula or conglomerate tumour, because it accurately differentiates between intra- and extraluminal structures.However, negative contrast facilitates quantitative evaluation of bowel wall thickening or enhancement and demonstrates gastrointestinal bleeding. CONCLUSION: MSCT of the small intestine is superior to conventional enteroclysis, especially in the diagnosis of mesenterial or other extraintestinal disease. As a side effect, the colon is assessed in the same examination. Radiation dose is less in MSCT (7.8-13.3 mSv) than in conventional fluoroscopy (13.99+/-7.57 mSv). MSCT can be performed as an alternative or adjunct to colonoscopy, if endoscopic access is restricted. It is already the imaging modality of choice in acute diverticulitis.

Administration, Oral↗

PubMed2003

[Radiological interventions in inflammatory bowel disease].

INTRODUCTION: Abscesses, fistulas,hemorrhages and stenoses are common complications of inflammatory bowel diseases. This study provides an overview on various methods of radiological intervention and the clinical usefulness of these methods is analyzed. METHODS: The success rate of percutaneous abscess drainage (PAD), embolisation of hemorrhages and dilatation of bowel stenoses is reviewed and current literature is addressed. Success rate is defined in terms of cure rate and need for subsequent surgery. RESULTS: After PAD, surgery can be avoided during the observation period in about 50% of patients with abscesses due to Crohn's disease and diverticulitis. Preoperative PAD reduces the degree of invasiveness and thus the risk of surgery. Abscess recurrence is found with the same frequency following surgery or PAD. Bowel dilatation can be performed both with radiological and with endoscopic guidance.Embolisation of GI-hemorrhage is technically feasible, but the indication should be limited to strictly selected cases. CONCLUSIONS: In treating abscesses and fistulas associated with Crohn's disease and diverticulitis, PAD is a valuable treatment option. Embolisation or dilatation are restricted to rare cares.

Abdominal Abscess↗

PubMed2003

[MRI with oral filling in patients with chronic inflammatory bowel diseases].

AIM: Evaluation of mannitol-MRI in patients with suspected or established Crohn's disease (CD). METHODS. 75 patients with suspected or established Crohn's disease were included. 1.5 l of mannitol-solution were administered orally within 1 h before imaging. A rectal filling was also employed. Butylscopolamin was applied i.v. Native-sequences were acquired. T1w sequences (axial, coronal) were acquired before and after (fs-T1-w-BH) i.v.Gd-DTPA. Additionally a dynamic CM-study was performed. RESULTS: In 45% of the examinations good image quality was achieved. In 28% opacification of the terminal ileum was insufficient. However, diagnostic assessment was possible. Motion artifacts due to breathing were rare, artifacts due to peristalsis were noted in 16% of the examinations. Alterations indicative to CD were found in 69% of the patients. The SI-increase of the thickened bowel-wall was significantly higher than the increase of not thickened wall (117 vs.75%; p = 0,001 in t-test). We detected stenoses in 56%, fistulas in 23% and an abscess in one patient. CONCLUSION: Mannitol-MRI is a valuable method in the diagnostic work-up of inflammatory bowel disease. Improvement of distal distension should be attempted, because of the good acceptance of the patients and high diagnostical value.

Administration, Oral↗

PubMed2003

[MRI in Crohn's disease after transduodenal contrast administration using negative oral MRI contrast media].

PURPOSE: To compare the efficacy and quality of conventional and MR enteroclysis with different filling methods regarding the assessment of extension and extraluminal manifestations in Crohn's disease. MATERIAL AND METHODS: 190 patients with known Crohn's disease were studied following small bowel enteroclysis, after oral administration or direct transduodenal filling in the MRI-department.T1- and T2-weighted breathhold MRI-scans w/o spectral fat suppression w/o i.v. Gd-DTPA were applied using negative oral superparamagnetic contrast media. RESULTS: Typical findings were marked bowel wall thickening with laminated wall contrast enhancement. In 135 patients 98,2% of affected bowel segments, 97,5% of stenoses and all 16 fistulas were detected, when conventional enteroclysis was employed as standard of reference. Additional important extraluminal findings such as ileoileal (n = 18), ileosigmoidal adhesions (n = 12), extraluminal abscesses (n = 35) and pseudotumors (n = 8) were visualized in 73/135 patients. Concerning the distension of jejunum and ileum, oral filling was rated significantly inferior to transduodenal filling in all small bowel segments,whereas filling in the MRI-unit was rated superior to fluoroscopic, mostly due to a mean transport time of 20 min to the MRI-unit. CONCLUSION: No clinically important findings of enteroclysis were missed when using MRI. Therefore, in patients with Crohn's disease, conventional enteroclysis can be replaced by MRI. For optimal bowel distension oral contrast administration is inferior to transduodenal filling, if a larger time delay between filling and the MRI-scan can be avoided.

Administration, Oral↗

PubMed2003

[Imaging of neuroendocrine tumors of the pancreas].

OBJECTIVE: To compare the value of the various imaging modalities in the detection of pancreatic islet cell tumors. METHODS: Analysis of the literature to compare the value of ultrasound, CT, MRI, angiography, venous sampling, scintigraphy and PET in the detection of neuroendocrine tumors of the pancreas. RESULTS: For transabdominal ultrasound a sensitivity of 60% has been reported; for endoscopic ultrasound a sensitivity of more than 90%. MRI with a sensitivity of 75-100% is more sensitive compared to CT with a sensitivity of 64-82%. Angiography and venous sampling have a reported sensitivity of 66% and 76%. Somatostatin receptor scintigraphy has a sensitivity of 81-88% with significant differences between the various histological subtypes of the pancreatic islet cell tumors. PET does not play an important role in the detection of neuroendocrine tumors of the pancreas. CONCLUSION: None of the various modalities is superior alone, so that it is often necessary to combine them for diagnostic imaging of pancreatic islet cell tumors.

Adenoma, Islet Cell↗

PubMed2003

[Volumetric MRI for evaluation of regional pattern and progressin of neocortical degeneration in Alzheimer's disease].

PURPOSE: Volumetric analysis of the corpus callosum and hippocampus using MRI in Alzheimer's disease (AD) to evaluate the regional pattern and progression of neocortical neurodegeneration. METHODS: In subsequent studies we investigated patients with AD and healthy controls. Volumetry was based on MRI-data from a sagittal 3D T1w-gradient echo sequence. The corpus callosum (CC) was measured in a midsagittal slice, and subdivided into 5 subregions. Volumetry of the hippocampus/amygdala-formation (HAF) was performed by segmentation in coronary reoriented slices. RESULTS: In AD patients we found a significant atrophy in the rostrum und splenium of CC. The atrophy was correlated with the severity of dementia, but no correlation was found with the load of white matter lesions. In comparison with (18)FDG-PET, we found a significant correlation of regional CC-atrophy with the regional decline of cortical glucose metabolism. A ROC-analysis demonstrated no significant differences in the diagnostic accuracy of HAF volumetry and regional CC volumetry of the splenium (region C5) even in mild stages of dementia. CONCLUSION: Regional atrophy of CC can be used as a marker of neocortical degeneration even in early stages of dementia in AD.

Alzheimer Disease↗

PubMed2003

Validation of cartilage volume and thickness measurements in the human shoulder with quantitative magnetic resonance imaging.

OBJECTIVE: To validate quantitative magnetic resonance imaging (qMRI) for the assessment of cartilage volume and thickness in thin and curved cartilage layers, such as the shoulder. METHODS: Eight shoulder specimens from healthy individuals (aged 31-69 years) were investigated using a 3D gradient echo sequence with selective water excitation. After segmentation with a B-spline Snake algorithm, the cartilage volume and thickness were determined three dimensionally. The cartilage volume data were compared with water displacement of surgically removed tissue, and the thickness with A-mode ultrasound. RESULTS: The glenoid and humeral head cartilage volume from qMRI agreed highly with that from water displacement (systematic difference, +/-1 to +/-3%; absolute difference, 4 to 7%). For the cartilage thickness, the mean systematic difference ranged from -17% (mean cartilage thickness of the glenoid) to +7% (maximal cartilage thickness of the glenoid); the standard error of the estimate was 3.7% for the humeral head, and 6.4% for the glenoid. CONCLUSIONS: The applied technique can be used for accurate determination of cartilage volume and thickness in human joints with highly curved and thin cartilage layers, such as the shoulder. In vivo application of this method will depend on the development of efficient surface coils that allow high resolution imaging under in situ conditions.

Adult↗

PubMed2003

[Systematic characterization of sonomorphological changes in the early stage of rheumatoid arthritis].

AIM: The early stage of rheumatoid arthritis (RA) is primarily manifested in the soft tissue of the hand. Although ultrasound (US) is regarded as an important imaging process in diagnostic medicine, precise characterization of sonomorphological changes has not yet been undertaken. METHOD: 20 patients with RA were examined with US. Two radiologists described semiquantitatively the characteristics of synovial changes in the hand in a consensus-based process and measured the synovial width. Statistical methods were used to determine whether the various synovial changes differed significantly and to identify the most frequent locations of changes. RESULTS: On the basis of the significant differences in morphology and synovial width, it is possible to distinguish between unremarkable findings, pannus tissue and band-like synovitis. Pannus tissue is most frequently found on the finger flexor tendons (FFT), the metacarpophalangeal joints (MCP) and the tendon of M. extensor carpi ulnaris (ECU). Band-like synovitis exhibits an uncharacteristic distribution pattern with a slight propensity to favour these locations. CONCLUSION: The FFT, MCP joints and ECU tendons are particularly important in systematic US screening of the hand for the purpose of establishing reliable evidence of inflammatory changes. Different stages of RA can be identified on the basis of the characteristic types of synovitis and the number of joints and tendons affected.

Adult↗

PubMed2003

[Functional CT imaging: Load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptiometry (CT-OAM)].

PURPOSE: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). MATERIALS AND METHODS: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (Delta 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a. p. projection). RESULTS: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p < 0.001). CONCLUSION: CT-OAM is a functional CT technique for visualizing and quantifying the distribution of the subchondral bone density, enabling a noninvasive load-dependent assessment of the joint surfaces. Load-dependent densitograms of hallux valgus specimens show a characteristic correlation with an increase of the HV-angle.

Absorptiometry, Photon↗

PubMed2003

[Functional MRI of the pelvic floor: postpartum changes of primiparous women after spontaneous vaginal delivery].

PURPOSE: Detection of morphological and functional changes of the pelvic floor with functional MRI in primiparous women after spontaneous vaginal delivery. METHODS AND MATERIALS: The study comprises 26 primiparous women after vaginal delivery and a control group of 41 healthy asymptomatic nulliparous volunteers. MRI was performed on a 1.5 T system in supine position with vagina and rectum opacified with Sonogel. The static images consisted of sagittal and axial T 2 -weighted SE sequences and functional images of true FISP sequences in midsagittal and axial planes acquired with the patient at rest, straining and during defecation. Evaluation of morphometric parameters included pelvimetry, thickness of the puborectal muscle and width of the urogenital hiatus as well as position and movement of the pelvic organs relative to the pubococcygeal reference line. RESULTS: The configuration of the bony pelvis did not differ for both groups. The puborectal muscle was significantly thinner in the study group (0.8 cm vs 0.6 cm). The functional images showed no significant differences between both groups at rest but a significantly increased incidence in the descent of the bladder neck, vaginal fornix and anorectal junction in the study group during straining. In addition, the primiparous women had more prominent rectoceles (0.6 cm vs 1.5 cm). CONCLUSION: Static imaging alone fails to demonstrate relevant pelvic floor changes and a functional method is necessary to evaluate the interactions of the pelvic organs regarding organ descent. Functional MRI of the pelvic floor is an excellent method to reveal the significant changes of the pelvic floor after vaginal birth without exposing the uterus to radiation.

Adult↗

PubMed2003

Endoscopic ultrasound-guided fine-needle aspiration biopsy of liver lesions: histological and cytological assessment.

BACKGROUND AND STUDY AIMS: EUS-guided fine-needle aspiration biopsy (EUS-FNA) is used increasingly for the diagnosis of mediastinal, biliopancreatic, and gastric tumors. However, little is known about EUS-FNA in hepatic lesions and the best method for tissue analysis. We assessed EUS-FNA combined with histological and cytological evaluation in selected patients. PATIENTS AND METHODS: 41 patients (66 +/- 7 years) were prospectively studied, 33 of whom had clinical findings suggestive of liver malignancies. Selection for EUS-FNA was based on an increased risk of bleeding from percutaneous biopsy (coagulopathy, cirrhosis, ascites, aspirin intake; n = 15), presence of small liver tumors < 2 cm (n = 12), or liver lesions found incidentally (n = 14). Transgastric EUS-FNA of lesions located in accessible liver segments was performed using the Hitachi FG-34UX longitudinal echo endoscope and a 22-G aspiration needle. Specimens were submitted separately for standard cytological and histological evaluation. In the case of malignancies, findings at surgery with histological examination, endoscopy, or computed tomography (CT)-guided biopsy of the primary cancer served as reference results (n = 33), while in benign disorders, a combination of imaging studies (Magnetic Resonance Tomography , scintigraphy) and the clinical follow-up, as summarized in the physician's report, was used as reference. RESULTS: EUS-FNA provided appropriate biopsy specimens in 40/41 patients. It was not possible to aspirate sufficient material in one patient. On average, 1.4 needle passes were necessary to obtain sufficient amounts of tissue. With regard to malignancy, the combination of histological and cytological examination had a sensitivity of 94%, specificity of 100%, negative predictive value (NPV) of 78%, and positive predictive value (PPV) of 100%. Tissue diagnoses were in agreement in 27/41 patients (65%). In the remaining patients, only the cytological examination identified six lesions correctly, while the histological assessment was correct in another seven patients. Malignant lesions were correctly identified by cytology in 24/33 (73%) patients, while histology alone was diagnostic for malignancy in 27/33 (82%) patients. When both modalities were combined, 31 out of 33-malignancies (94%) were correctly diagnosed. Minor complications occurred in two patients and consisted of self-limiting local bleeding. CONCLUSIONS: EUS-FNA of liver tumors is a powerful, reliable, and safe procedure for the diagnosis of malignant liver lesions. Optimal diagnostic results are achieved by combining cytological with histological assessment. Hence, EUS-FNA is an alternative to percutaneous biopsy, particularly in patients at risk of bleeding or with small lesions of the liver.

Aged↗

PubMed2003

[CT-guided aortic balloon occlusion in traumatic abdominal and pelvic bleeding].

PURPOSE: To introduce a new interventional method for CT-guided aortic balloon occlusion in patients with life-threatening abdominal or pelvic bleeding. MATERIALS AND METHODS: Three male patients (age 18, 30, and 45 years) with multiple trauma underwent CT-guided balloon occlusion of the aorta after CT identified an active abdominal or pelvic bleeding site and the patients became unstable (systolic blood pressure, BP < 80 mm Hg) despite resuscitation continuous volume. Using a right femoral approach, a 9F sheath was immediately introduced and the positions of the guide wire and balloon catheter (20 x 40 mm) were intermittently checked with CT scans and CT fluoroscopy. In one case, a C-clamp was applied to the pelvic ring under CT guidance for emergency stabilization of an unstable pelvic fracture. RESULTS: CT-guided aortic balloon occlusion and the mounting of the pelvic C-clamp were technically successful. Intervention time was 4 to 6 minutes for aortic balloon occlusion. All patients became at least temporarily stable hemodynamically with the blood pressure rising above 100 mmHg. The infrarenal occlusion catheters were left in place up to 60 minutes. Suprarenal occlusion was not performed. Two patients died due to protracted shock and complex injuries (injury severity score (ISS: 50 - 64). CONCLUSION: CT-guided aortic occlusion provides fast and effective bleeding control immediately after completion of the diagnostic CT. The procedure can be combined with other specific emergency surgical or interventional procedures. Experience with more patients is necessary for further evaluation of this new technique.

Adolescent↗

PubMed2003

Practicability and acute haematological toxicity of 2- and 3-weekly CHOP and CHOEP chemotherapy for aggressive non-Hodgkin's lymphoma: results from the NHL-B trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL).

BACKGROUND: There is evidence that intensified variants of the classical 3-weekly CHOP-21 chemotherapy [cyclophosphamide (C), doxorubicin (H), vincristine (O), prednisone (P)] may improve treatment outcome in aggressive lymphoma. Three variants using either an addition of etoposide (CHOEP-21: 100 mg/m(2) on days 1-3), the shortening to 2-week intervals using recombinant human granulocyte colony-stimulating factor (rhG-CSF; CHOP-14) or both (CHOEP-14) are currently compared with CHOP-21 in the NHL-B trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL). To enable more extensive testing of these schemes we here characterise their practicability regarding schedule adherence, acute haematotoxicity and need for supportive treatment. PATIENTS AND METHODS: The trial included patients with normal lactate dehydrogenase (LDH) aged </=60 years (NHL-B1) and patients aged 61-75 years (NHL-B2). The data are taken from an interim analysis. Data from 959 patients (CHOP-21: 232; CHOP-14: 238; CHOEP-21: 244; CHOEP-14: 245) from 162 institutions with a total of 5331 therapy cycles were evaluated. RESULTS: The dose adherence in the NHL-B1 trial was excellent. The median relative dose (RD; i.e. actually given compared to planned dose) exceeds 98% for the myelosuppressive drugs in all four regimens. Only </=5% of patients received a relative dose <80% (RD <80). The median treatment duration could be shortened as scheduled for both CHOP-14 by 36 days and CHOEP-14 by 35 days. The dose adherence in the NHL-B2 trial was excellent for CHOP-21 and CHOP-14 for the myelosuppressive drugs (median RD >/=98%, RD <80 </=15%). Addition of etoposide, however, was accompanied by more dose erosion (median RD >/=97%, RD <80 </=17% for CHOEP-21 and </=27% for CHOEP-14). The median treatment duration could be shortened by 34 days with CHOP-14 compared with CHOP-21. Less treatment shortening was feasible for CHOEP-14 compared with CHOP-21 (median of 29 days). CHOP-14 and CHOP-21 were similar regarding toxicity profile, rate of infection, use of antibiotics, rate of transfusions and hospitalisation. CHOEP schemes were associated with a higher rate of infections, more transfusion requirements, more antibiotic use and longer hospitalisation than the CHOP schemes, particularly in patients aged >60 years. Haematopoietic recovery was age- and treatment-related. CONCLUSIONS: CHOP-14 with the addition of rhG-CSF is safe and practicable in a large multicentre setting in patients aged 18-75 years. Despite shorter treatment intervals it can be delivered at the same dose as the classical 3-weekly CHOP with a comparable toxicity profile. The addition of etoposide is feasible and safe for patients </=60 years old in both the CHOEP-21 and CHOEP-14 schemes. For patients >60 years of age the addition of etoposide is associated with marked dose erosion due to increased toxicity. In this age group CHOEP should be used with caution.

Acute Disease↗

PubMed2003

Non-invasive intravenous coronary angiography using electron beam tomography and multislice computed tomography.

BACKGROUND: Electron beam computed tomography (EBCT) and multislice computed tomography (MSCT) are both suitable for non-invasive identification of coronary stenoses. OBJECTIVE: To compare intravenous coronary EBCT angiography (EBCTA) and MSCT angiography (MSCTA) with regard to image quality and diagnostic accuracy. METHODS: EBCTA was done using an Imatron C-150 XP scanner in 101 patients following a standard protocol (slice thickness 3 mm, overlap 1 mm, acquisition time 100 ms, prospective ECG trigger). For MSCTA in a different set of 91 patients (using a Siemens Somatom Plus4VZ scanner), the whole volume of the heart was covered in a spiral technique by four simultaneous detector rows. Using retrospective ECG gating, the raw data were reconstructed in (mean (SD)) 215 (12) axial slices acquired in diastole (slice thickness 1.25 mm, overlap 0.5 mm, acquisition time 250 ms/slice). RESULTS: With EBCTA, 76% of predetermined coronary segments in a nine segment model could be assessed with diagnostic image quality, and with MSCTA, 82%. A low contrast to noise ratio with EBCTA, and the presence of motion artefacts with MSCTA were the main reasons for inadequate image quality. Using conventional angiography as the gold standard, 77% of stenoses of > 50% could be identified correctly with EBCTA and 82% with MSCTA. Significant stenoses were correctly ruled out in 93% of segments with EBCTA, and in 96% of segments with MSCTA. The average contrast to noise ratio was higher with MSCTA than with EBCTA (9.4 v 6.5; p < 0.001). CONCLUSIONS: EBCTA and MSCTA show similarly high levels of accuracy for determining and ruling out significant coronary artery stenoses. MSCTA is capable of providing good image quality in more coronary segments than EBCTA because of its better contrast to noise ratio and higher spatial resolution. Motion artefacts seen at heart rates of > 75 beats/min and a higher radiation exposure are the main limitations of MSCTA.

Coronary Angiography↗

PubMed2003

Moving-table MR angiography of the peripheral runoff vessels: comparison of body coil and dedicated phased array coil systems.

OBJECTIVE: The aim of our study was to compare the signal-to-noise ratio and the diagnostic accuracy of moving-table MR angiography of the peripheral arteries with body coil and dedicated phased array coil systems. SUBJECTS AND METHODS: Forty patients were examined with digital subtraction angiography and moving-table MR angiography with a 1.5-T MR imaging system either with a body coil (n = 20) or with a dedicated phased array coil (n = 20). The timing of contrast material was performed with real-time MR fluoroscopy. RESULTS: For the iliac artery, upper leg, and lower leg, the mean values for signal-to-noise ratios were 56, 51, and 17, respectively, for the body coil, and 54, 74, and 64, respectively, for the dedicated phased array coil. For the body coil, sensitivity and specificity in identifying stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 96%, respectively, for the upper leg. For the dedicated phased array coil, sensitivity and specificity for stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 98%, respectively, for the upper leg. Sensitivity and specificity were inferior for the body coil (88% and 85%) compared with the dedicated phased array coil (100% and 96%) in the lower leg. A significant difference of the mean values of contrast-to-noise ratio was found before and after subtraction for the dedicated phased array coil and body-coil techniques (Student's t test, p < 0.01). CONCLUSION: In comparison with the body coil, the dedicated peripheral phased array surface coil system improves signal-to-noise ratio for the upper and lower leg and diagnostic accuracy in the lower leg.

Adult↗

PubMed2002

Multicenter study for the evaluation of a dedicated biopsy device for MR-guided vacuum biopsy of the breast.

The purpose of this multicenter study was to determine the accuracy and clinical value of a dedicated breast biopsy system which allows for MR-guided vacuum biopsy (VB) of contrast-enhancing lesions. In five European centers, MR-guided 11-gauge VB was performed on 341 lesions. In 7 cases VB was unsuccessful. This was immediately realized on postinterventional images or direct follow-up combined with histopathology-imaging correlation; thus, a false-negative diagnosis was avoided. Histology of 334 successful biopsies yielded 84 (25%) malignancies, 17 (5%) atypical ductal hyperplasias, and 233 (70%) benign entities. Verification of malignant or borderline lesions included reexcision of the biopsy cavity. Benign histologic biopsy results were verified by retrospective correlation with the pre- and postinterventional MRI and by subsequent follow-up. Our results indicate that MR-guided VB, in combination with the dedicated biopsy coil, offers the possibility to accurately diagnose even very small lesions that can only be visualized or localized by MRI.

Biopsy↗