Search PubMed⌕ Search

Biomedical subjects

M Reiser

Publications and source records attributed to M Reiser.

At least 379 records · Page 21Linked to original sources
PubMed1997

Choledocholithiasis after Billroth II surgery: MR cholangiographic diagnosis.

In this case of choledocholithiasis in a patient with previous Billroth-II surgery and cholecystectomy we demonstrate the advantages of a heavily T2-weighted half-Fourier turbo-spin-echo (HASTE) sequence. This technique allows thin-slice snapshot imaging with 1.4 s per slice eliminating motion artifacts and still has the necessary heavy T2-weighting to depict biliary fluid with high contrast. In the presented case endoscopic retrograde cholangiography (ERCP) could not be performed prior to MRI due to technical problems. In a second attempt, ERCP was successful and a common bile duct stone as diagnosed by MRI before could be removed. We conclude that HASTE snapshot MR cholangiography can be used as a clinically valuable tool when other noninvasive methods are not diagnostic.

Aged↗
PubMed1997

Imaging findings in patients with ventral dural defects and herniation of neural tissue.

The aim of this paper is to describe clinical and imaging findings in three patients with ventral dural defects and herniation of the spinal cord or cauda equina. The literature is reviewed and the clinical, radiological and operative findings are compared. Three patients with ventral dural defects of different etiologies are presented. One patient gave a longstanding history of ankylosing spondylitis, the second patient presents 37 years after spinal trauma, and the third patient presents with spontaneous spinal cord herniation. All patients had typically slowly progressive neurological symptoms with multiple hospitalizations until diagnosis was made. Characteristic findings in postmyelographic CT included a ventral or ventrolateral displacement with deformation of the spinal cord or the cauda equina. Sagittal MRI showed this abrupt and localized anterior deviation of the spinal cord or the cauda equina to the posterior portions of a vertebral body with or without a bony vertebral defect optimally. Additionally, due to the ventral displacement of the spinal cord, the dorsal subarachnoid space was relatively enlarged without evidence of an arachnoid cyst, in all patients. Magnetic resonance imaging and postmyelographic CT can diagnose ventral dural defects with spinal cord herniation or nerve root entrapment. Dural defects must be considered in the presence of neurological symptoms in cases of longstanding ankylosing spondylitis, late sequelae of fractures of vertebral bodies, and without history of spinal trauma or surgery.

Aged↗
PubMed1997

Dynamic MR colpocystorectography assessing pelvic-floor descent.

Magnetic resonance colpocystorectography (MR-CCRG) is presented in the evaluation of patients with pelvic-floor disorders. Five healthy volunteers and 44 female patients with isolated or combined visceral descent underwent dynamic MRI and dynamic fluoroscopy (DF). MR-CCRG was performed with the patient in a supine position using a True FISP sequence (1 image/1.2 s; in-plane resolution 1.02 mm) during pelvic floor contraction, relaxation, and straining maneuvers. Relevant organs, such as urethra, bladder, vagina, and rectum, were opacified by using a saline solution, Magnevist (Schering AG, Berlin, Germany), and sonography gel, respectively. The clinical evaluation and the intraoperative results (30 cases) were used as reference. MR-CCRG and DF were non-diagnostic in 3 cases each. Most patients had a combined type of visceral prolapse, the most frequent combination being a vaginal vault prolapse and a cystocele. The points of reference were sufficiently outlined by DF and MR-CCRG. In comparison with the clinical and intraoperative results, MR-CCRG proved to be especially beneficial in the diagnosis of different types of enteroceles including a uterovaginal prolapse. MR-CCRG showed an equal or higher sensitivity and specificity for all individual sites when compared with DF. Also, predominant herniation obscuring other concomitant prolapse could be verified in 8 cases. MR-CCRG is superior to DF and accurately depicts pelvic-floor descent and prolapse in women. The possibility of dynamic presentation (see enclosed CD-ROM) allows for a better understanding of the organ movements within a given topographic reference setting.

Contrast Media↗
PubMed1997

Spiral CT angiography and 3D reconstruction in patients with aortic coarctation.

The objective of this study was to assess the reliability of spiral CT angiography (CTA) and 3D reconstruction in patients with aortic coarctation (CoA). Eighteen patients with suspected or surgically proven coarctation were examined by spiral CT. In addition to the axial slices, 3D reconstructions, such as shaded surface display (SSD) and maximum intensity projection (MIP), were used to determine the diameters of the CoA and the pre- and poststenotic aorta and to visualise the collateral vessels. Diameters derived from cardiac catheterization were compared with those from CTA in 8 patients. The degree of aortic stenosis was correlated with blood pressure gradients (BPG) in 12 patients. The difference between the diameters of the CoA and the pre- and poststenotic aorta derived from MIP and angiography was not statistically significant (p = 0.69). With SSD the internal thoracic artery was detected in 16 and the posterior intercostal artery in 13 cases. The degree of aortic stenosis correlated poorly with the BPG (r = 0.51, r2 = 0.26). CTA with 3D reconstruction represents a reliable noninvasive technique for the assessment of the degree of CoA and the visualisation of collateral vessels. It may serve as a follow-up investigation after intervention or surgical treatment.

Adolescent↗
PubMed1997

Non-invasive determination of cartilage thickness throughout joint surfaces using magnetic resonance imaging.

Data on articular cartilage thickness in the living are important for the design for computer models, aimed at preoperatively assessing the effect of surgical procedures on joint contact and load transmission, and for the calculation of cartilage material properties from its deformational behavior as determined during arthroscopy. A non-invasive method for measuring cartilage thickness in living subjects is, however, not available. A technique based on magnetic resonance imaging has therefore been tested for assessing articular cartilage thickness throughout joint surfaces. The accuracy is determined by comparing cartilage thickness maps obtained from three patellar specimens with a fat-suppressed three-dimensional gradient-echo sequence (resolution 2 x 0.31 x 0.31 mm) to those obtained with CT arthrography, A-mode ultrasound and anatomical sections. The distribution patterns are quantitatively compared using image analysis. The highest agreement was obtained for MRI and the sections (50% identical pixels), but all techniques yielded very similar results. On average, MR slightly underestimated the cartilage thickness compared with CT and the sections, and overestimated it compared with ultrasound. No evidence of differences in the degree of similarity could be detected in areas of thin and thick cartilage. We conclude that, if the resolution and accuracy of the method presented are considered acceptable, MRI is available for repeatable determination of topographical maps of articular cartilage thickness in living subjects. These data can be used to determine joint contact and stress in computer models and to calculate cartilage material properties in vivo.

Adult↗
PubMed1997

Paradoxical expansion of intracranial tuberculomas during chemotherapy.

A patient from India with military lung tuberculosis who developed intracranial tuberculomas under treatment with tuberculostatics is described. Computed tomography (CT) scans of the brain showed a progress of tuberculomas despite effective tuberculostatic therapy and adjunctive corticosteroid treatment. This phenomenon, termed 'paradoxical response' has rarely been reported. Continuation of chemotherapy led to improvement of brain lesions and a recovery of miliary tuberculosis. When intracranial tuberculomas develop, therapy should be continued for longer than is customary for uncomplicated tuberculosis infections. The use of steroids to suppress a 'paradoxical response' is not proven.

Adult↗
PubMed1997

Serum interleukin 4 and interleukin 10 levels in patients with chronic hepatitis C virus infection.

BACKGROUND/AIMS: Immune-mediated mechanisms are believed to play an important pathogenetic role in chronic hepatitis C virus infection. Interleukin 4 (IL-4) and IL-10 are secreted by T helper-2 type cells (Th2) which may downregulate cell-mediated immune effector mechanisms important in the host defense against intracellular pathogens. This study aimed to determine Th2 cytokine levels in chronic hepatitis C virus infection. METHODS: Serum IL-4 and IL-10 levels were measured in 74 patients with chronic hepatitis C virus infection and 20 healthy controls. The expression of CD30 in liver, a marker that is preferentially expressed in Th2 cells, was also determined by immunohistochemical staining in 37 patients. RESULTS: Serum IL-4 and IL-10 were below the detection limit (5 pg/ml) in all 20 healthy controls. However, 36 patients (49%) had elevated serum IL-4 levels (range 5-106 pg/ml, p<0.001) and 23 patients (31%) had elevated serum IL-10 levels (range 5-37 pg/ml, p<0.05). There was no correlation between serum IL-4 and IL-10 levels. There was also no correlation between serum IL-4 and IL-10 levels and any of the clinical (age, gender, mode of acquisition), biochemical (serum alanine transaminase levels), virologic (viremia level, genotype), and histological parameters examined. Twenty of 37 liver biopsy specimens from patients with chronic hepatitis C virus infection showed occasional CD30+ lymphocytes, suggestive of Th2 phenotype. However, in 20 of the 37 patients with paired cryostat liver sections, IL-4 was not detected in any of these patients, suggesting that IL-4 was not produced in the liver in patients with chronic hepatitis C virus infection. CONCLUSIONS: This study showed that serum Th2 cytokines are elevated (but at a low level) in a proportion of patients with chronic hepatitis C virus infection. However, the elevated Th2 cytokine levels may represent a systemic response and not a result of increased local production within the liver.

Adult↗
PubMed1997

Imaging of the hand: degeneration, impingement and overuse.

Degenerative and overuse diseases as well as impingement syndromes of the hand are illustrated and discussed in this review article. Osteoarthritis of the interphalangeal joints as described by Heberden and Bouchard is a ubiquitous articular disease often associated with synovitis and erosive joint destruction. Osteoarthritis of the trapeziometacarpal joint is classified into four stages for proper indication of operation. Overuse can result in stenosing tenosynovitis around the wrist and in synovitis with or without impingement of the flexor or extensor tendons of the digitis or ruptures of the annular and cruciform pulleys. Although diagnosis of these entities is usually made by history and clinical investigation, ultrasound and MRI can be helpful tools in imaging of these diseases. Scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) are the characteristic degeneration pattern of the wrist and represent the degeneration mechanisms in scapholunate insufficiency and nonunion of the scaphoid. SLAC wrist is a gradual degeneration classified in three stages and found in posttraumatic scapholunate rupture, calcium pyrophosphate dehydrate deposition disease (CPPD), rheumatoid arthritis, neuropathic diseases, trauma, and beta 2-microglobulin associated amyloid deposition. Ulna impaction syndrome is increasingly recognized as a cause of ulnar sided pain and exhibits a characteristic MRI appearance.

Cumulative Trauma Disorders↗
PubMed1997

A non-invasive technique for 3-dimensional assessment of articular cartilage thickness based on MRI. Part 2: Validation using CT arthrography.

Established methods for the measurement of articular cartilage thickness are invasive and cannot be sequentially applied in living subjects. In the present study, the distribution of cartilage thickness throughout entire joint surfaces was determined from MR images obtained with a fat-suppressed gradient-echo sequence at a resolution of 0.31 x 0.31 x 2.00 mm3, and compared to that derived from CT arthrography. A minimal distance algorithm was employed to produce 3D cartilage thickness maps of seven cadaveric human knee joints. The mean amount of deviation of the cartilage volumes was 5.6% (+/- 4.6), statistical analysis showing that there was high agreement between the two methods (r = 0.995, slope = 1.037, y-intercept = -90.5 mm3). The 3D thickness maps yielded a striking agreement between the two methods, the maximum values generally yielding a deviation of none or one thickness interval of 0.5 mm. This investigation shows that accurate 3D assessment of articular cartilage thickness can be performed with MRI, this technique having the advantage that it is suitable for investigating living subjects.

Adult↗
PubMed1997

[Increased liver density in computed tomography as a result of anti-arrhythmia therapy with amiodarone].

PURPOSE: To assess whether the hepatic density on CT scans of patients receiving amiodarone therapy differs significantly from the hepatic density of a control group not receiving the drug. METHODS: Hepatic density was assessed by CT in 31 patients receiving amiodarone, 7 receiving short-term (12-14 days), 8 receiving mid-term (20-89 days) and 16 receiving long-term therapy (3-26 months), as well as in a control group of 15 patients. RESULTS: Mean liver density of all patients under amiodarone therapy (77.9 +/- 11.7 HU) was significantly higher (p < 0.005) than in the control group (56.6 +/- 2.8 HU). The smallest increase in density was found in patients with short-term therapy (64.8 +/- 3.4 HU; p < 0.05), the greatest increase in patients with long-term therapy (85.0 +/- 8.9 HU; p < 0.001). CONCLUSION: In patients receiving amiodarone therapy, a significantly increased hepatic density on CT scans is observed. This finding has to be considered as a differential diagnosis to other hepatopathies with increased density of the liver.

Adult↗
PubMed1997

[Lymph node staging in cervix carcinomas: the results of high-resolution magnetic resonance tomography (MRT) with a phased-array body coil].

PURPOSE: To determine the diagnostic value of high resolution MR imaging with a circularly polarised (c.p.) body phased-array coil for the staging of pelvic lymph nodes in cervical carcinoma. MATERIAL AND METHODS: 42 patients with histologically proven carcinoma of the cervix were studied on a 1.5 T scanner by using a c.p. body phased-array coil. The imaging protocol included T2-weighted turbo-spin-echo (TSE) and T1-weighted spin-echo sequences pre and post i.v. application of Gd-DTPA; slice thickness was 5-7 mm and pixel size 0.53 mm2. Lymph nodes with a diameter of > or = 8 mm were considered to have metastatic involvement. MR imaging results were compared with histopathologic findings. RESULTS: MR imaging showed enlarged lymph nodes (> or = 8 mm) in 16 of 18 patients with histologic proof of lymph node metastases (sensitivity 89%). In 22 of 24 cases MR findings were true negative (specificity 92%). Diagnostic accuracy was 91%. CONCLUSION: High-resolution MR imaging with a c.p. body phased-array coil provides high sensitivity, specificity, and diagnostic accuracy for pelvic lymph node staging in cervical carcinoma.

Adult↗
PubMed1997

[Parametrial infiltration of cervix carcinoma: diagnostic value of contrast-enhanced fat-suppressed T1-weighted SE sequences at 1.5 tesla].

PURPOSE: To determine whether contrast-enhanced and fat-suppressed sequences contribute to the MR imaging diagnosis of parametrial invasion. METHODS: 21 patients with carcinoma of the cervix were prospectively examined with a phased-array coil and a 1.5T MR-scanner using the following sequences: transverse T2-weighted turbo spin echo (T2-TSE), T1-weighted spin echo (T1-SE) and fat suppressed T1-weighted SE sequences before and after Gd-DTPA. The sequences were evaluated separately for the presence of parametrial invasion. Image quality and diagnostic confidence were classified on a scale of 0-10 (nondiagnostic-excellent). Findings were compared to the results of the pathohistological examination. RESULTS: Sensitivity, specificity and diagnostic accuracy were highest for T2-TSE sequences (100%, 79% and 86%, respectively). Contrast-enhanced T1-SE sequences with fat-suppression (71%, 79%, and 76%) showed no improvement compared to T2-TSE. Unenhanced fat-suppressed T1-SE (100%, 30%, and 56%) and unenhanced T1-SE (100%, 7%, and 38%) as well as contrast-enhanced T1-SE (86%, 20%, and 47%) were significantly worse than T2-TSE. With similar image quality (p < 0.05) diagnostic confidence was higher on T2-TSE than on any of the other sequences (p < 0.001). CONCLUSION: Considering the cost-effectiveness of the examination, for the MR diagnosis of parametrial invasion the use of fat-suppressed contrast-enhanced sequences can be abandoned in favour of T2-weighted TSE sequences.

Adult↗
PubMed1997

[A report on experience with a second-generation PACS installation in routine computed tomographic operations].

PURPOSE: Our institute has been using a pilot SIENET-PACS system for the last five years; its advantages and disadvantages in daily use are described. MATERIAL AND METHODS: The SIENET system connects 2 CT, 3 MRT and 2 angiographic installations with 7 viewing consoles and with an optical archive. From January 1994 to 1997 approximately 19,000 patients were examined by CT and the results stored digitally in the PACS system. RESULTS: A representative analysis of selected patient data revealed problems in 12.8% of patients with regard to the radiological information system and also the hospital information system. While the digital data proved satisfactory, the production of digital images was excellent but time-consuming. The image archive was reliable but required greater capacity for our purposes. CONCLUSIONS: Manual retrieval of patient data presented problems and integration of the radiology information system and PADS is essential. Digital data gathering is an advantage. Digital imaging is too slow and should be improved by more suitable software. Integration of new archival storage methods and compatibility with the DICOM standard is, judging form our experience, essential.

Angiography, Digital Subtraction↗
PubMed1997

[Morphology and contrast enhancement of ductal carcinoma in situ in dynamic 1.0 T MR mammography].

PURPOSE: The detectability with magnetic resonance mammography (MR-M) of non-invasive ductal carcinoma in situ (DCIS), its morphology, and patterns of contrast enhancement were studied. MATERIAL AND METHODS: A total of 849 MR-M examinations were performed in 741 patients using a dynamic, contrast-enhanced FLASH 3D sequence at 1.0 T. Surgical breast biopsies were obtained in 332 cases. Histological work-up confirmed 164 carcinomas, including 20 DCIS. RESULTS: Of 20 DCIS, 14 were correctly diagnosed by MR-M on the basis of focal increase of signal intensity. In two cases (10%), no increase of signal intensity was observed. In another three cases (15%), multifocal enhancement lead to a false-negative diagnosis. In one case (5%), DCIS was a random finding in a patient diagnosed and treated for adjacent phylloides tumour. The sensitivity of MR-M was 70%. 4 (20%) of the DCIS did not show microcalcifications at conventional mammography and were only detected at MR-M. The sensitivity of conventional mammography also amounted to 70%. However, the combination of both imaging methods increased sensitivity to 90%. CONCLUSION: Ductal carcinoma in situ is not reliably detectable by MR-mammography alone due to lack of a uniform pattern of enhancement.

Biopsy↗
PubMed1997

[Spiral CT angiography in demonstration of cerebral aneurysms before and after treatment with titanium clips].

PURPOSE: To determine the suitability of spiral CT angiography (SCTA) in patients with intracerebral titanium aneurysm clips. MATERIAL AND METHOD: The section parameters were optimised using a phantom. 16 patients were examined preoperatively and 18 following treatment of aneurysms with clips. RESULTS: The resolution, sensitivity and specificity for demonstrating cerebral aneurysms measuring > or = 3 mm was 91.3% and 75% respectively. In 15 patients with intracerebral clips there were no or only minor artefacts; three examinations were of no value because of major metal artefacts. Amongst six aneurysms demonstrated angiographically, two, which measured more than 3 mm, could be shown by SCTA. CONCLUSION: SCTA was able to demonstrate intracerebral aneurysms measuring > or = 3 mm. Titanium clips did not usually affect image quality significantly.

Adolescent↗
PubMed1997

[Three-dimensional thickness and volume measurements of the knee joint cartilage using MRI: validation in an anatomical specimen by CT arthrography].

PURPOSE: In the present study we intended to validate knee joint cartilage volume and thickness measurements with MRI. METHODS: Ten fresh cadaver knees (age 29 to 64 yrs.) were sagittally imaged, using a fat-suppressed FLASH-3D sequence with a resolution of 2 x 0.31 x 0.31 mm3. Then, a contrast agent was injected and the specimens submitted to CT arthrography. From both modalities the patellar, femoral, and tibial cartilages were segmented semiautomatically and reconstructed three-dimensionally. The cartilage thickness was determined independently of the sectional plane, based on a "minimal distance algorithm". RESULTS: The volumes and the regional distribution patterns yielded a very high degree of similarity on direct comparison of both imaging modalities. The average volume error between MRI and CT was 3.8% (+/- 3.0%), the correlation 0.998, the slope of the regression line 1.04 and the gamma-intercept -80 mm3. The analysis yielded no significant differences between the two methods (Wilcoxon signed rank test, 5% level) in the patella, femur, medial, and lateral tibia. CONCLUSION: The results suggest that, based on a fat-suppressed FLASH sequence with high resolution and three-dimensional concepts of digital image analysis, the cartilage volume and thickness can be analysed non-invasively and with high accuracy by MRI.

Algorithms↗
PubMed1997

[Contrast media enhanced magnetic resonance angiography for determining patency of a coronary bypass. A comparison with coronary angiography].

AIM: Assessment of graft patency with current non-invasive MRA techniques is particularly difficult for evaluating internal mammary artery grafts. Our aim is to determine the accuracy of a contrast enhanced MRA technique is assessing graft patency. METHODS: We examined 19 patients with a total of 53 grafts (32 venous/21 arterial), using an ultrafast contrast enhanced 3D gradient-echo technique and compared this with the results of selective angiography. RESULTS: Sensitivity of the contrast enhanced method was 95.2% for venous grafts, 94.4% for IMA grafts and 94.8% overall. Specificity was 85.7% overall, 90.9% for venous and 66.7% for IMA grafts. Positive predictive value was 94.4%. CONCLUSION: Compared with previous studies, visualisation of IMA grafts was improved by using contrast enhanced MRA. In this preliminary study, contrast enhanced MRA proved promising for the assessment of graft patency.

Adult↗