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M Reiser

Publications and source records attributed to M Reiser.

At least 145 records · Page 8Linked to original sources
PubMed2000

Digital radiography of the skeleton using a large-area detector based on amorphous silicon technology: image quality and potential for dose reduction in comparison with screen-film radiography.

AIM: The purpose of this study was to evaluate a large-area, flat-panel X-ray detector (FD), based on caesium-iodide (CsI) and amorphous silicon (a-Si) with respect to skeletal radiography. Conventional images were compared with digital radiographs using identical and reduced radiation doses. MATERIALS AND METHODS: Thirty consecutive patients were studied prospectively using conventional screen-film radiography (SFR; detector dose 2.5 microGy). Digital images were taken from the same patients with detector doses of 2.5, 1.25 and 0.625 microGy, respectively. The active-matrix detector had a panel size of 43 x 43 cm, a matrix of 3 x 3K, and a pixel size of 143 microm. All hard copies were presented in a random order to eight independent observers, who rated image quality according to subjective quality criteria. Results were assessed for significance using the Student's t -test (confidence level 95%). RESULTS: A statistically significant preference for digital over conventional images was revealed for all quality criteria, except for over-exposure (detector dose 2.5 microGy). Digital images with a 50% dose showed a small, statistically not significant, inferiority compared with SFR. The FD-technique was significantly inferior to SFR at 75% dose reduction regarding bone cortex and trabecula, contrast and overall impression. No statistically significant differences were found with regard to over- and under-exposure and soft tissue presentation. CONCLUSION: Amorphous silicon-based digital radiography yields good image quality. The potential for dose reduction depends on the clinical query.

Aged↗
PubMed2000

Validation of high-resolution water-excitation magnetic resonance imaging for quantitative assessment of thin cartilage layers.

OBJECTIVE: To employ a magnetic resonance (MR) imaging technique for quantitative assessment of thin cartilage layers, and to validate the cartilage volume and thickness measurements. METHODS: We investigated 10 normal elbow joints (age 20 to 69 years) with a 3D gradient echo sequence with selective water excitation (TR 18 ms; TE 9 ms; FA 25 degrees, resolution 1x0.25x0.25 mm2, imaging time 19 min). After interpolating the image data to a 0.125x0.125 mm2 in-plane resolution, the cartilage plates were segmented, reconstructed in 3D, and the cartilage volume and thickness determined with a 3D Euclidean distance transformation algorithm, independent of the original section plane. The cartilage volume and thickness values were compared with CT arthrography and A-mode ultrasound. RESULTS: The mean systematic difference between the elbow cartilage volume obtained from MR imaging and CT arthrography was -0.11% (-6.0 mm3) and the mean random difference 5.7% (314 mm3). Except for the fovea capitis radii, the deviations were not statistically significant (range -7.6 to +11.7%). In the humerus, the mean cartilage thickness (average = 1.35 mm) was overestimated relative to CT arthrography (+20.7%/+0.23 mm), and slightly underestimated relative to A-mode ultrasound (-6.0%/-0.05 mm). With few exceptions, there were no significant differences between MRI, CT arthrography and ultrasound in the other joint surfaces of the elbow (random deviations between 0.08 and 0.39 mm). CONCLUSIONS: The technique presented can be applied for determining the cartilage volume and 3D thickness in joints with thin cartilage layers with a reasonable degree of accuracy.

Adult↗
PubMed2000

A technique for 3D in vivo quantification of proton density and magnetization transfer coefficients of knee joint cartilage.

OBJECTIVE: To develop an MR-based method for the in vivo evaluation of the structural composition of articular cartilage. DESIGN: Five sagittal magnetic resonance imaging (MRI) protocols were acquired throughout the knee joint of 15 healthy volunteers and the boundaries of the cartilage segmented from a previously validated sequence with high contrast between cartilage and surrounding tissue. The other sequences were matched to these data, using a 3D least-squares fit algorithm to exclude motion artefacts. In this way secondary images were computed that included information about the proton density (interstitial water content) and the magnetization transfer coefficient (macromolecules, collagen). The average signal intensities of the 3D cartilage plates were extracted from these data sets and related to a phantom. RESULTS: The signal intensity data showed a high interindividual variability for the proton density (patella 31%, lateral tibia 36%, medial tibia 29%); the patella displaying higher values than the tibia (P< 0.001). There were high correlations between the three plates. The magnetization transfer coefficient also showed high variability (patella 25%, lateral tibia 32%, medial tibia 30%) with the lowest values in the medial tibia (P< 0.01) and lower correlations between the plates. The slice-to-slice variation (medial to lateral) ranged from 9% to 24%. CONCLUSION: An MR-based method has been developed for evaluating the proton density and magnetization transfer of articular cartilage in vivo and observing systematic differences between knee joint cartilage plates. The technique has the potential to supply information about the water content and collagen of articular cartilage, in particular at the early state of osteoarthritic degeneration.

Adult↗
PubMed2000

[Effects of biphasic spiral CT, conventional and iron oxide enhanced MRI on therapy and therapy costs in patients with focal liver lesions].

PURPOSE: Evaluation of the diagnostic efficacy and cost-benefit of contrast enhanced CT (CT) and MRI pre- and post-SPIO-particles in focal hepatic disease with consideration of therapeutic outcome. METHODS: In 52 patients with the suspicion of primary or secondary hepatic malignancy, biphasic spiral CT and breath-hold gradient-echo T1- and fast spin-echo T2-weighted MRI pre- and post-iron oxide administration (1.5 T, body-phased-array coil) were compared. The number of hepatic lesions and the related diagnoses resulting from each imaging modality were recorded and statistically correlated to the final diagnoses established by biopsy/OP (34/52), long term follow-up of 12 months (18/52), and a consensus reading of all imaging modalities considering all clinical imaging information. The most likely induced therapy resulting from each imaging test was correlated to the final therapy. Based on data from the hospitals accountants, the therapy-related costs were estimated without hospitalization costs. RESULTS: In 34/52 (65.4%) of the cases the correct diagnosis was primarily stated by CT (sensitivity [se.] 85.2%, specificity [sp.] 44.0%). In additional 10/52 of the cases unenhanced MRI (se. 91.4%, sp. 75.0%) enabled correct diagnoses, and in another 6 cases the diagnosis was established only by SPIO-MRI (se. 100%, sp. 86.7%). Considering the possible therapeutic recommendation arising from each modality, CT would have induced needles therapy costs of 191,042 DM, unenhanced MRI of 171,035 DM, and SPIO-MRI of 7,311 DM. In comparison to the real therapy costs of 221,873 DM, this would have corresponded to an unnecessary increase of therapy costs of 86.1%, 77.1%, and 3.3%, respectively. In two cases (1 hemangioma, 1 regenerative nodule) all modalities failed, causing unnecessary surgery in one patient. DISCUSSION: In this problem-oriented scenario unenhanced and SPIO-enhanced MRI proved to be superior to CT regarding diagnostic efficacy. The cost-benefit resulted mainly due to preserving patients from unnecessary surgical procedures.

Adenoma, Liver Cell↗
PubMed2000

Mesalazine changes apoptosis and proliferation in normal mucosa of patients with sporadic polyps of the large bowel.

BACKGROUND AND STUDY AIMS: Regular intake of nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the occurrence of colorectal adenoma and carcinoma, possibly by inducing apoptosis and/or decreasing proliferation in colorectal epithelial cells. Mesalazine is widely used in the treatment of patients with inflammatory bowel disease, and well tolerated. We investigated its effect on apoptosis and proliferation of colorectal mucosa in 21 patients with sporadic polyps of the large bowel. PATIENTS AND METHODS: In total, 17 patients with sporadic colorectal polyps (> or = 5 mm) underwent polypectomy and biopsy of uninvolved mucosa before and after treatment with 1 g/d mesalazine for 1, 3, 7 or 14 days. Four additional patients served as untreated controls. Apoptotic index (AI) was measured by terminal deoxynucleotidyl transferase-mediated d-uridine triphosphate nick-end labeling (TUNEL) assay; proliferation index (PI) was measured by immunohistochemical examination with anti-Ki67 antibody. RESULTS: AI was significantly increased 1 and 3 days after initiation of treatment with mesalazine compared with controls (P= 0.0107 for the 1-day treatment group and P=0.0142 for the 3-day treatment group), and seemed to remain largely unchanged after longer treatment duration. Proliferation appeared to be decreased by mesalazine in all treatment groups, while proliferation in controls did not change (P=0.0107 for the 1-day treatment group and P= 0.0142 for the 3-day treatment group compared with controls. CONCLUSIONS: Mesalazine significantly induces apoptosis and decreases proliferation in colorectal mucosa in patients with sporadic polyps of the large bowel. This may be clinically relevant in that it may lower the rate of polyp recurrence after polypectomy, thereby possibly contributing to the chemoprevention of sporadic colorectal carcinoma.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

[Spondylolysis in the developmental stage: diagnostic contribution of MRI].

PURPOSE: To assess the value of MR imaging in demonstrating ongoing spondylolysis in adolescents. METHODS: MRI was performed in 9 juvenile patients (3 female, 6 male aged 8-16 years; mean 12.5 y) with pain during hyperextension. In 6 patients a CT scan and in 5 a plain film was available. RESULTS: In all patients bone marrow edema was found in the pars interarticularis and the pedicle, which was bilateral in 4 patients. In 7/9 cases the L5 vertebra was affected, in 2/9 cases spondylolysis was found in L4. In 3 cases the edema reached the middle third of the vertebral body and a tumor was suspected. In all CT scans a bilateral incomplete or complete cleft in the pars inter-articularis was found. In 4/6 CT-scans a sclerosis was seen in the area of the bone marrow edema. Only in 1/5 plain films was there a suspicion for a spondylolysis, four examinations were completely normal. CONCLUSIONS: To eliminate underlying causal conditions of spondylolysis and to install specific therapy, early diagnosis is mandatory. MR imaging should be the first and only imaging modality in young patients with low back pain during and after exercise and pain with hyperextension. Bone scans and CT scans should be avoided due to irradiation, plain films usually do not reveal pathological findings in developing sponylolysis.

Adolescent↗
PubMed2000

[Magnetic resonance imaging of the wrist--comparison of high resolution pulse sequences and different fat signal suppression techniques in cadavers].

PURPOSE: To evaluate high resolution sequences with and without fat-suppression techniques for MR imaging of the wrist. MATERIALS AND METHODS: 10 cadaver wrist specimens were imaged with 12 MR sequences (SE: 400 ms/20 ms, TSE: 3000 ms/119 ms/17 ms, fatsat (FS) TSE: 3000 ms/17 ms and 3000 ms/45 ms, STIR: 2619 ms/29 ms/160 ms, DESS 3D: 43.7 ms/9 ms/35 degrees FS and 25.4 ms/9 ms/35 degrees water excitation (WE), CISS 3D: 12.2 ms/5.9 ms/40 degrees and FLASH-sequences: 53 ms/11 ms/40 degrees FS, 23 ms/11 ms/40 degrees WE and 45 ms/11 ms/30 degrees FS) at 1.5 T. Slice thickness was 3 mm, FOV 80 x 70 mm (pixel size 0.31 x 0.31 mm). Signal intensity was measured by an ROI in bone marrow, fluid, hyaline cartilage, scapholunate (SL) ligament and triangular fibrocartilage and S/N- and C/N-ratios were calculated. Additionally, a visual evaluation was performed. RESULTS: The highest homogeneity and the least artifacts were achieved by the T1-w SE sequence. For the STIR and PD-FS TSE sequence high rankings were found for the detection of free water. The PD FS sequence had high ranking also for visualization of the SL ligament and the triangular fibrocartilage. The best sequence for the assessment of hyaline cartilage was the FLASH-FS sequence. For detailed analysis of bony structures the CISS sequence performed best. CONCLUSION: The isolated use of a PD-FS-TSE sequence enables for evaluation of all clinically relevant structures at the wrist. Dedicated questions for hyaline cartilage are answered best by the use of a FLASH 3D-FS sequence. Selective water excitation reduces acquisition time to 60%, nevertheless FS sequences are still diagnostically superior to WE sequences.

Adipose Tissue↗
PubMed2000

Transjugular intrahepatic portosystemic shunt for cirrhosis and ascites: Effects in patients with organic or functional renal failure.

BACKGROUND: A transjugular intrahepatic portosystemic shunt (TIPS) is increasingly being used for treatment of patients with refractory ascites and functional renal failure. In contrast, organic renal disease is commonly considered a relative contraindication for TIPS placement. The aim of this pilot study was to investigate the effects of TIPS in patients with refractory ascites and organic or functional renal impairment. METHODS: A TIPS was placed for refractory or intractable ascites in 10 consecutive patients with liver cirrhosis and impaired renal function (serum creatinine > 1.5 mg/100 ml). Four of them had organic kidney disorders. Of these patients, three had moderate renal impairment, and one had end-stage renal disease and needed hemodialysis every other day. The other six patients had functional renal impairment due to the underlying liver disease. RESULTS: TIPS was effective in reducing ascites in 8 of 10 patients, including all patients with organic renal disease. Furthermore, after TIPS the renal function improved in all patients. Serum creatinine and serum urea levels decreased significantly from 1.8 +/- 0.1 to 1.5 +/- 0.1 mg/100 ml (P < 0.05) and from 107 +/- 13 to 78 +/- 14 mg/100 ml (P < 0.05), respectively. The renal function of the three patients with organic renal failure improved similarly, as observed in the six patients with functional renal failure. In the patient on hemodialysis, TIPS was effective in reducing the frequency of paracenteses. CONCLUSION: TIPS may be useful in patients with functional and in patients with organic renal disease, resulting in improvement of ascites and renal function.

Aged↗
PubMed2000

Magnetic resonance-based motion analysis of the shoulder during elevation.

Changes in shoulder motion patterns are relevant in various shoulder diseases, but no in vivo information exists about the relative positions in vivo of the shoulder girdle bones and the supraspinatus muscle in three-dimensional space. Thus, the objective of this study was to perform a motion analysis of these structures during passive arm elevation using open magnetic resonance imaging and three-dimensional image processing. Fourteen volunteers were examined in five positions of abduction (30 degrees-150 degrees) with an open magnetic resonance system. After segmentation and three-dimensional reconstruction, the axis of the supraspinatus, humerus, clavicle, and the plane of the glenoid were determined, and the relative movements were calculated. The ratio for glenohumeral to scapulothoracic motion was 1.5:1 at 60 degrees and 2.4:1 at 120 degrees abduction. At 30 degrees, the axis of the supraspinatus was nearly horizontal, and during abduction a continuous elevation (+123 degrees at 150 degrees abduction) was measured. In the transverse plane, the angle between the supraspinatus and the clavicle axes became larger during abduction because of an increasing retroversion of the clavicle. The study shows specific three-dimensional motion patterns for each bone of the shoulder girdle and the supraspinatus muscle during passive elevation. The technique and results can be used for future studies in patients with pathologic changes of shoulder girdle motion.

Adult↗
PubMed2000

Chest radiography with a large-area detector based on cesium-iodide/amorphous-silicon technology: image quality and dose requirement in comparison with an asymmetric screen-film system.

The purpose of this study was to evaluate a large-area, flat-panel X-ray detector, which uses cesium-iodide (CsI) and amorphous silicon (a-Si). Conventional images were compared with digital images acquired with equal dose (2.5 microGy) and with 50% dose reduction. Fifteen consecutive patients were studied prospectively using an asymmetric screen-film system (detector dose, 2.5 microGy). Digital images were taken from the same patients in a posteroanterior view with detector doses of 2.5 and 1.25 microGy, respectively. The CsI/a-Si active-matrix imager had a panel-size of 43 x 43 cm, a matrix of 3 x 3k, and a pixel-pitch of 143 microm. Hard copies were presented in a random order to eight independent observers, who rated image quality according to six subjective quality criteria. Statistical significance of differences was evaluated with Student's t test for paired samples (confidence level, 95%). Digital radiographs with 2.5 and 1.25 microGy were superior to conventional images regarding all quality criteria. Statistically significant differences were observed for five of six criteria at a detector dose of 2.5 microGy and for only one quality feature at 1.25 microGy. Flat-panel digital imagers based on CsI/a-Si technique have the potential to replace conventional systems and might allow a reduction of radiation dose by 50% without loss of image quality.

Adult↗
PubMed2000

Focal liver lesions: evaluation of the efficacy of gadobenate dimeglumine in MR imaging--a multicenter phase III clinical study.

PURPOSE: To evaluate gadobenate dimeglumine (Gd-BOPTA) for dynamic and delayed magnetic resonance (MR) imaging of focal liver lesions. MATERIALS AND METHODS: In 126 of 214 patients, MR imaging was performed before Gd-BOPTA administration, immediately after bolus administration of a 0.05- mmol/kg dose of Gd-BOPTA, and 60-120 minutes after an additional intravenously infused 0.05-mmol/kg dose. In 88 patients, imaging was performed before and 60-120 minutes after a single, intravenously infused 0.1-mmol/kg dose. T1- and T2-weighted spin-echo and T1-weighted gradient-echo images were acquired. On-site and blinded off-site reviewers prospectively evaluated all images. Intraoperative ultrasonography, computed tomography (CT) during arterial portography, and/or CT with iodized oil served as the reference methods in 110 patients. RESULTS: Significantly more lesions were detected on combined pre- and postcontrast images compared with on precontrast images alone (P <. 01). All reviewers reported a decreased mean size of the smallest detected lesion and improved lesion conspicuity on postcontrast images. All on-site reviewers and two off-site reviewers reported increased overall diagnostic confidence (P <.01). Additional lesion characterization information was provided on up to 109 (59%) of 184 delayed images and for up to 50 (42%) of 118 patients in whom dynamic images were assessed. Gd-BOPTA would have helped change the diagnosis in 99 (47%) of 209 cases and affected patient treatment in 408 (23%) of 209 cases. CONCLUSION: Gd-BOPTA increases liver lesion conspicuity and detectability and aids in the characterization of lesions.

Adult↗
PubMed2000

Sialolithiasis: MR sialography of the submandibular duct--an alternative to conventional sialography and US?

PURPOSE: To determine the value of magnetic resonance (MR) sialography for the diagnosis of sialolithiasis by comparing results prospectively with those of ultrasonography (US) and digital sialography. MATERIALS AND METHODS: MR sialography was prospectively performed with T2-weighted three-dimensional (3D) constructive interference in steady-state (CISS) and rapid acquisition with relaxation-enhancement (RARE) sequences in 24 patients suspected of having sialolithiasis. Evoked salivation was used as contrast material. T1-weighted spin-echo and T2-weighted turbo spin-echo MR imaging also were performed. The results were then compared with those of US and digital sialography, with the latter as standard of reference. RESULTS: The 3D CISS images were significantly (P: <.05) superior to RARE images for demonstrating the submandibular ductal system, followed by T2-weighted turbo spin-echo images (P: <.01) and T1-weighted spin-echo images (P: <.001). The sensitivity and specificity were 100% and 80%, respectively, for CISS MR sialography and 80% and 100%, respectively, for RARE MR imaging. The sensitivity and specificity of US were both 80%. CONCLUSION: MR sialography with evoked salivation is noninvasive and allows delineation of the submandibular ductal system and detection of sialoliths with accuracy that is similar to that of digital sialography and superior to that of US.

Humans↗
PubMed2000

Detection and mapping of intraabdominal adhesions by using functional cine MR imaging: preliminary results.

PURPOSE: To identify and map intraabdominal adhesions by using functional cine magnetic resonance (MR) Imaging. MATERIALS AND METHODS: Twenty-seven patients suspected of having intraabdominal adhesions were examined. Section-by-section dynamic depiction of induced visceral slide throughout the whole abdomen was achieved by using a transverse or sagittal true fast imaging with steady-state precession sequence. Location and type of diagnosed adhesions were documented by using the nine segments of the abdominal map. These criteria and intraoperative results were compared in 13 patients. RESULTS: MR images depicted a total of 42 intraabdominal adhesions; 21 (50%) were in the lower abdomen. The most common types of adhesions were located between the ventral abdominal wall and small-bowel loops (n = 10 [24%]) and between adjacent small-bowel loops (n = 9 [21%]). Comparison with the intraoperative results showed a sensitivity of 87.5% and a specificity of 92.5%. MR imaging was most accurate in depicting adhesions to the abdominal wall (15 [94%] of 16) and subperitoneal space (eight [100%] of eight). The presence of adhesions between bowel loops was overestimated. CONCLUSION: Detection of visceral slide at functional cine MR imaging is easy to perform and represents a well-tolerated and accurate procedure for use in the identification of intraabdominal adhesions in patients with chronic pain and equivocal clinical findings.

Abdomen↗
PubMed2000

Treatment of primary progressive Hodgkin's and aggressive non-Hodgkin's lymphoma: is there a chance for cure?

PURPOSE: To determine differences in prognosis between primary progressive Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL), we retrospectively analyzed patients with progressive lymphoma who were treated with different salvage chemotherapy regimens including high-dose chemotherapy (HDCT) followed by autologous stem-cell support (ASCT). PATIENTS AND METHODS: One hundred thirty-one patients with primary progressive lymphoma (HD, n = 67; NHL, n = 64) were enrolled. Primary progressive disease was defined as disease progression during first-line chemotherapy or only transient response (complete or partial response lasting </= 90 days) after induction treatment. Patients 60 years or younger with progressive lymphoma were eligible to receive HDCT with ASCT. RESULTS: The overall response rate after salvage chemotherapy for patients with primary progressive HD and NHL was 33% and 15%, respectively. Twenty-five HD patients (37%) received HDCT. Most patients with NHL had progressive disease under salvage treatment, with only six patients (10%) receiving HDCT. Of those, only two patients were alive and in continuous complete remission 3 and 12 months after HDCT. No patient with NHL survived longer than 26 months after first diagnosis. Actuarial OS after 5 years was 19% for all HD patients; 53% for HD patients receiving HDCT, and 0% for patients who did not receive HDCT. In HD patients, multivariate regression analysis identified chemosensitive disease on salvage treatment (P =.0001) and HDCT (P =.031) as significant prognostic factors for freedom from treatment failure. Significant prognostic factors for OS are chemosensitive disease (P =.0005), HDCT (P =.039), and B symptoms at the time of progress (P =.046). CONCLUSION: There are striking differences in the prognosis of patients with progressive HD and aggressive NHL. The prognosis of progressive NHL patients is dismal. Most patients have rapidly progressive disease after salvage treatment and are, therefore, excluded from HDCT programs. In contrast, progressive HD patients can achieve long-term survival after HDCT.

Adolescent↗
PubMed2000

[A new in vivo technique for 3-dimensional analysis of the translation of femoral condyles and the menisci responding to antagonistic muscle forces].

The aim of our study was to develop a 3-D MR-based technique for the analysis of meniscal and femoral translations during flexion of the knee, and under the influence of antagonistic muscle forces in healthy subjects. In an open MR system, 5 knees were examined at 30 degrees and 90 degrees flexion using a T1-weighted 3-D gradient echo sequence. A force of 30 Newtons, first in the extending and then in the flexing direction, was applied to the distal lower leg. After three-dimensional reconstruction, the minimal distances between the centre of the tibial plateau and the posterior edge of the menisci and femoral condyles were determined. At 30 degrees flexion, the minimum distance for the meniscus was larger medially than laterally (23.2 +/- 1.8 mm vs. 16.2 +/- 3.3 mm), and this also applied to the condyles (25.1 +/- 1.5 vs. 19.0 +/- 3.0 mm). During flexion to 90 degrees, a posterior translation of 0.5 +/- 0.2 mm was observed for the lateral, and of 3.4 +/- 1.2 mm for the medial, meniscus. The condyles demonstrated a different posterior translation (lateral 2.2 +/- 0.56 mm; medial 1.8 +/- 1.9 mm). No obvious differences were found between extension and flexion muscle activity for the different positions of the knee. In the present study, a new 3-D technique is presented for the analysis of the femoral and meniscal translation at various positions of the knee, and under muscle activity. The results suggest different translation for the menisci and condyles.

Adult↗
PubMed2000

[Precision MRI-based joint surface and cartilage density analysis of the knee joint using rapid water-excitation sequence and semi-automatic segmentation algorithm].

The aim of this study was to analyse the precision of three-dimensional joint surface and cartilage thickness measurements in the knee, using a fast, high-resolution water-excitation sequence and a semiautomated segmentation algorithm. The knee joint of 8 healthy volunteers, aged 22 to 29 years, were examined at a resolution of 1.5 mm x 0.31 mm x 0.31 mm, with four sagittal data sets being acquired after repositioning the joint. After semiautomated segmentation with a B-spline Snake algorithm and 3D reconstruction of the patellar, femoral and tibial cartilages, the joint surface areas (triangulation), cartilage volume, and mean and maximum thickness (Euclidean distance transformation) were analysed, independently of the orientation of the sections. The precision (CV%) for the surface areas was 2.1 to 6.6%. The mean cartilage thickness and cartilage volume showed coefficients of 1.9 to 3.5% (except for the femoral condyles), the value for the medial femoral condyle being 9.1%, and for the lateral condyle 6.5%. For maximum thickness, coefficients of between 2.6 and 5.9% were found. In the present study we investigate for the first time the precision of MRI-based joint surface area measurements in the knee, and of cartilage thickness analyses in the femur. Using a selective water-excitation sequence, the acquisition time can be reduced by more than 50%. The poorer precision in the femoral condyles can be attributed to partial volume effects that occur at the edges of the joint surfaces with a sagittal image protocol. Since MRI is non-invasive, it is highly suitable for examination of healthy subjects (generation of individual finite element models, analysis of functional adaptation to mechanical stimulation, measurement of cartilage deformation in vivo) and as a diagnostic tool for follow-up, indication for therapy, and objective evaluation of new therapeutic agents in osteoarthritis.

Adult↗