Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 55 records · Page 3Linked to original sources

PubMed2005

Effect of dose on image quality in a detector-based dual-exposure, dual-energy system for chest radiography.

PURPOSE: To assess the image quality of subtracted soft tissue and bone images of a CsI-detector-based dual-energy system for chest radiography at varying dose levels. MATERIAL AND METHODS: We evaluated a CsI-detector-based, dual-exposure, dual-energy prototype system; 126 patients were categorized into groups of small, medium, and large. Fixed values were applied for mAs and mA. The patients were randomized into two groups with intended higher and lower speed pairs of approximately 400/1000 (high and low energy shot) and 200/500, respectively. True speed equivalents were calculated retrospectively using the detector dose. Image quality was evaluated by two highly experienced radiologists in consensus applying a rating scale of 1 to 5 for quality indicators such as image noise, residual bone structures, motion artifacts, and others. RESULTS: Significantly decreased noise and a significant improvement for display of bone details in the bone image were noted with the higher dose, whereas a significant increase in motion artifacts reduced image quality at the higher dose. CONCLUSION: Radiation dose did not significantly influence the perception of dual-energy image quality. Dual-energy subtraction, as described, has the potential to become a future routine application in chest radiography.

Aged↗

PubMed2005

Magnetic resonance cholangiopancreatography: image quality, ductal morphology, and value of additional T2- and T1-weighted sequences for the assessment of suspected pancreatic cancer.

PURPOSE: To assess image quality and duct morphology on magnetic resonance cholangiopancreatography (MRCP) and also the value of additional T2- and T1-weighted sequences for differentiation of benignity and malignancy in patients with suspected pancreatic tumors. MATERIAL AND METHODS: One-hundred-and-fourteen patients received MRCP and unenhanced and contrast material-enhanced MR imaging. MR results were analyzed independently by two blinded readers, and subsequently correlated with the results from surgery, biopsy, and follow-up. Assessment included the evaluation of image quality, duct visualization and morphology, and the differentiation of pancreatic lesion status (benign versus malignant). RESULTS: Overall, 49 patients had benign final diagnoses, while 65 had a malignant diagnosis. Image quality of single-shot thick-slab MRCP was rated significantly better than the MIP images of multisection MRCP. With MRCP alone, the two readers' accuracy in the assessment of pancreatic lesion status was 72% (95% CI, 64% to 83%) and 69% (95% CI, 56% to 77%), respectively; with the addition of T2- and T1-weighted images the accuracy significantly improved to 89% (95% CI, 82% to 95%) and 84% (95% CI, 77% to 92%) for readers 1 and 2, respectively. CONCLUSION: Single-shot thick-slab MRCP and multisection MRCP provide complementary results; however, single-shot MRCP had superior image quality. Moreover, assessment of ductal morphology with MRCP alone facilitated the diagnosis of different pathologic conditions of the pancreatobiliary system in the majority of patients. However, with the addition of T2- and T1-weighted sequences the overall diagnostic accuracy was significantly improved and thus we consider that a comprehensive MR approach should comprise both MRCP techniques and parenchymal sequences.

Adult↗

PubMed2005

Colon dissection: a new three-dimensional reconstruction tool for computed tomography colonography.

PURPOSE: To improve the sensitivity of computed tomography (CT) colonography in the detection of polyps by comparing the 3D reconstruction tool "colon dissection" and endoluminal view (virtual colonoscopy) with axial 2D reconstructions. MATERIAL AND METHODS: Forty-eight patients (22 M, 26 F, mean age 57 +/- 21) were studied after intra-anal air insufflation in the supine and prone positions using a 16-slice helical CT (16 x 0.625 mm, pitch 1.7; detector rotation time 0.5 s; 160 mAs und 120 kV) and conventional colonoscopy. Two radiologists blinded to the results of the conventional colonoscopy analyzed the 3D reconstruction in virtual-endoscopy mode, in colon-dissection mode, and axial 2D slices. RESULTS: Conventional colonoscopy revealed a total of 35 polyps in 15 patients; 33 polyps were disclosed by CT methods. Sensitivity and specificity for detecting colon polyps were 94% and 94%, respectively, when using the "colon dissection", 89% and 94% when using "virtual endoscopy", and 62% and 100% when using axial 2D reconstruction. Sensitivity in relation to the diameter of colon polyps with "colon dissection", "virtual colonoscopy", and axial 2D-slices was: polyps with a diameter >5.0 mm, 100%, 100%, and 71%, respectively; polyps with a diameter of between 3 and 4.9 mm, 92%, 85%, and 46%; and polyps with a diameter < 3 mm, 89%, 78%, and 56%. The difference between "virtual endoscopy" and "colon dissection" in diagnosing polyps up to 4.9 mm in diameter was statistically significant. CONCLUSION: 3D reconstruction software "colon dissection" improves sensitivity of CT colonography compared with the endoluminal view.

Colon↗

PubMed2005

Imaging and radiological interventions of portal vein thrombosis.

Portal vein thrombosis (PVT) is diagnosed by imaging methods. Once diagnosed by means of ultrasound, Doppler ultrasound can be performed to distinguish between a benign and malignant thrombus. If further information is required, magnetic resonance angiography or contrast-enhanced computed tomography is the next step, and if these tests are unsatisfactory, digital subtraction angiography should be performed. Many papers have been published dealing with alternative methods of treating PVT, but the material is fairly heterogeneous. In symptomatic non-cavernomatous PVT, recanalization using local methods is recommended by many authors. Implantation of transjugular intrahepatic portosystemic shunt is helpful in cirrhotic patients with non-cavernomatous PVT in reducing portal pressure and in diminishing the risk of re-thrombosis. In noncirrhotic patients with recent PVT, some authors recommend anticoagulation alone. In chronic thrombotic occlusion of the portal vein, local measures may be implemented if refractory symptoms of portal hypertension are evident.

Angiography↗

PubMed2005

Magnetic resonance imaging including magnetic resonance cholangiopancreatography for tumor localization and therapy planning in malignant hilar obstructions.

PURPOSE: To assess image quality and overall accuracy of magnetic resonance imaging (MRI), including two magnetic cholangiopancreatography (MRCP) techniques, for the diagnostics and preoperative work-up of malignant hilar obstructions. MATERIAL AND METHODS: Thirty-one patients with malignant hilar obstructions (hilar cholangiocarcinoma, n=30; hepatocellular carcinoma, n=1) received MRCP by two techniques (single-shot thick-slab and multisection thin-slice MRCP) and unenhanced and contrast material-enhanced MRI. MR assessment included the evaluation of image quality and visualization of bile ducts (5-point scale), and the classification of tumor status. MR results were subsequently correlated with the results from surgery and pathology. RESULTS: The maximum intensity projections of multisection thin-slice MRCP had significantly more artifacts compared to MRCP in the single-shot thick-slab technique, and overall image quality of single-shot thick-slab MRCP was rated significantly superior compared to multisection thin-slice MRCP (4.4 +/- 0.7 and 4.1 +/- 0.9, respectively). Moreover, ductal visualization of different parts of the biliary system was rated superior with single-shot thick-slab MRCP. In contrast, the original data from multisection thin slice MRCP facilitated visualization of periductal lesions and adjacent structures. Overall MR accuracy for the assessment of tumor status, periductal infiltration, and lymph node metastases was 90%, 87%, and 66%, respectively. CONCLUSION: For evaluation of malignant hilar obstructions, MRCP by the single-shot thick-slab technique had superior image quality and fewer artifacts; in contrast, besides sole biliary visualization, multisection MRCP depicted complementary adjacent parenchymal and periductal structures. We therefore recommend MRI, with a combination of both MRCP techniques, for the diagnostic work-up and therapy planning of malignant hilar obstructions.

Adult↗

PubMed2004

Value of image fusion using single photon emission computed tomography with integrated low dose computed tomography in comparison with a retrospective voxel-based method in neuroendocrine tumours.

The objective was the evaluation of single photon emission computed tomography (SPECT) with integrated low dose computed tomography (CT) in comparison with a retrospective fusion of SPECT and high-resolution CT and a side-by-side analysis for lesion localisation in patients with neuroendocrine tumours. Twenty-seven patients were examined by multidetector CT. Additionally, as part of somatostatin receptor scintigraphy (SRS), an integrated SPECT-CT was performed. SPECT and CT data were fused using software with a registration algorithm based on normalised mutual information. The reliability of the topographic assignment of lesions in SPECT-CT, retrospective fusion and side-by-side analysis was evaluated by two blinded readers. Two patients were not enrolled in the final analysis because of misregistrations in the retrospective fusion. Eighty-seven foci were included in the analysis. For the anatomical assignment of foci, SPECT-CT and retrospective fusion revealed overall accuracies of 91 and 94% (side-by-side analysis 86%). The correct identification of foci as lymph node manifestations (n=25) was more accurate by retrospective fusion (88%) than from SPECT-CT images (76%) or by side-by-side analysis (60%). Both modalities of image fusion appear to be well suited for the localisation of SRS foci and are superior to side-by-side analysis of non-fused images especially concerning lymph node manifestations.

Adult↗

PubMed2004

Combined 123I-FP-CIT and 123I-IBZM SPECT for the diagnosis of parkinsonian syndromes: study on 72 patients.

72 consecutive patients with suspected parkinsonian syndromes (PS) were studied by dopamine transporter (DAT) and D2 receptor SPECT in order to evaluate the accuracy of combined SPECT imaging. In the follow-up, the patients were diagnosed as having Parkinson's disease (PD, n = 25), dementia with Lewy bodies (DLB, n = 6), multiple system atrophy (MSA, n = 13), progressive supranuclear palsy (PSP, n = 8), corticobasal degeneration (CBD, n = 9), and essential tremor (ET, n = 11). Using the iteratively estimated optimal cutoffs, DAT was reduced in 57/61 PS patients, whereas all ET patients were identified as "normal". Reduced D2 receptor binding had 7/13 patients with MSA, 6/8 patients with PSP, 2/9 patients with CBD and no ET, PD or DLB patients. FP-CIT SPECT allows an accurate detection of nigrostriatal affection in neurodegenerative PS. IBZM SPECT is useful to approve the diagnosis of PSP and MSA although a normal finding cannot exclude an atypical PS. IBZM SPECT seems to be of restricted value in CBD.

Aged↗

PubMed2004

MRI after magnetic drug targeting in patients with advanced solid malignant tumors.

The purpose of this study was to evaluate the ability of MRI to detect magnetic particle uptake into advanced solid malignant tumors and to document the extension of these tumors, carried out in the context of magnetic drug targeting. In a prospective phase I trial, 11 patients were examined with MRI before and after magnetic drug targeting. The sequence protocol included T1-WI and T2-WI in several planes, followed by quantitative and qualitative evaluation of the signal intensities and tumor extensions. In nine patients, a signal decrease was observed in the early follow-up (2-7 days after therapy) on the T2-weighted images; two patients did not show a signal change. The signal changes in T1-WI were less distinct. In late follow-up (4-6 weeks after therapy), signal within nine tumors reached their initially normal level on both T1-WI and T2-WI; two tumors showed a slight signal decrease on T2-WI and a slight signal increase on T1-WI. Within the surveillance period, tumor remission in 3 out of 11 patients was observed, and in 5 patients tumor growth had stopped. The remaining three patients showed significant tumor growth. There was no statistically significant correlation between signal change and response. MRI is a suitable method to detect magnetite particles, deposited at the tumor site via magnetic drug targeting. MRI is therefore eligible to control the success of MDT and to assess the tumor size after the end of therapy.

Adolescent↗

PubMed2004

[Current concepts and recent developments of laser ablation in tumor therapy].

PURPOSE: The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. METHODS; Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors-bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. RESULTS: In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. CONCLUSIONS: The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results.

Adult↗

PubMed2004

[Magnetic resonance tomography guided focussed ultrasound surgery (MRgFUS) in tumor therapy--a new noninvasive therapy option].

The demand for minimal or non-invasive therapies especially in tumor therapy is increasing constantly. High frequency focussed ultrasound represents an effective and safe alternative to established thermoablative procedures. In this article we report the advantages of MR-guidance for focussed ultrasound. We describe first clinical experiences in the treatment of uterine fibroids, breast cancer and fibroadenomas of the breast employing MR-guided focussed ultrasound surgery (MRgFUS). This method offers strong potential in the treatment also of other tumorentities since it provides excellent accuracy. Currently numerous efforts are undertaken to introduce MRgFUS for the therapy of liver or cerebral tumors.

Breast Neoplasms↗

PubMed2004

[CT-guided interstitial brachytherapy of lung malignancies. Technique and first results].

CT-guided interstitial brachytherapy of lung malignancies is a novel technique combining (192)Iridium brachytherapy with modern CT guidance for applicator positioning and 3D dosimetry. Initially, this technique has been developed for the treatment of liver malignancies. In the following we describe this novel technique as well as initial results for the treatment of lung malignancies.

Brachytherapy↗

PubMed2004

[Part-body hyperthermia with a radiofrequency multiantenna applicator under online control in a 1.5 T MR-tomograph].

Objective of this study is the integration of a multiantenna applicator for part-body hyperthermia (BSD 2000/3D) in a 1.5 T MR-tomograph (Siemens Magnetom Symphony) in order to perform noninvasive MR monitoring in real time to increase safety and effectiveness of heat treatments. The positioning unit is mechanically coupled to the MR gantry from the back side and the body coil is utilised for imaging. For that purpose, the hyperthermia antenna system (100 MHz, 1.500 W) and the MR receiver (63.9 MHs) have to be decoupled in terms of high frequency (filter) and electromagnetically (emc). The processing of MR data sets is performed in a hyperthermia planning system. A simultaneous operation of radiofrequency hyperthermia and MR system is possible at clinically relevant power levels. MR imaging is used for tumor-diagnostics (standard spin echo sequences), for hyperthermia planning (T1-weighted gradient echo sequences in equal- and opposed-phase techniques), and for temperature measurements according to the proton resonance frequency method (PRF method, phase evaluation registration using a gradient echo sequence with long echo time). In 33 patients with advanced pelvic and abdominal tumors we performed 150 heat sessions under MR monitoring. For 70% of these patients a visualisation of temperature sensitive data during treatment was possible. The evaluated difference images represent a superposition of real temperature -increase and a (temperature-induced) perfusion elevation. The -hybrid approach renders development of part body hyperthermia possible as an MR-controlled intervention in radiology.

Abdominal Neoplasms↗

PubMed2004

[Short-term CT findings after osteosynthesis of fractures of the vertebral spine].

PURPOSE: Evaluation of a correlation between surgical stabilization of fractures of the vertebral spine and postoperative short-term CT findings with special attention to degenerative changes. MATERIALS AND METHODS: The pre- and post-operative CT of 55 patients (43male, 12 female, age: 7 - 73 years, mean = 37.7 years) with traumatic fractures of the vertebral spine who underwent surgical stabilization using an internal fixator were analyzed retrospectively. The interval between surgical intervention and first postoperative CT control did not exceed one week. The interval to the second short-term follow-up CT ranged from 6 up to 24 months (mean: 10.3 +/- 2.7 months). The consensus reading of the short-term CT by two experienced radiologists was compared to the pre- and immediately postoperative CT examinations and with the neurologic findings. Statistical analysis was done using the chi-square- or the Fisher's exact-test. RESULTS: No statistically significant correlation (p > 0.05) was found between the patient's age and the postoperative incidence of osteoporosis, spondylarthrosis, scoliosis, spondylolisthesis or disc protrusion after posttraumatic surgical stabilization using an internal fixator. Also, there was no significant correlation between the fracture's type or location, presence of polytraumatization, the technique of surgical intervention, and the incidence of postoperative degenerative changes in the neighboring segments. The thesis has not been verified (p > 0.05) that polysegment stabilization or prior surgical interventions at the vertebral spine with scar induction are responsible for a higher rate of degeneration. The only risk factor observed for postoperative scoliosis was the burst rotation fracture type C1.3 (AO-classification). CONCLUSIONS: No short-term acceleration of degenerative changes after surgical intervention in vertebral spine fractures was observed. However, due to the short-term interval between surgical intervention and follow-up CT (mean: 10.3 +/- 2.7 months), a final conclusion cannot yet be drawn. A follow-up CT seems to be indicated in patients with increasing complaints during this period. Thus, low grade complications can be diagnosed early.

Adolescent↗

PubMed2004

[Iodine delivery rate of different concentrations of iodine-containing contrast agents with rapid injection].

PURPOSE: To determine how the concentration of iodinated contrast media for computed tomography studies affects the iodine delivery rate at various conditions. MATERIALS AND METHODS: Three nonionic, iodinated contrast agents that are marketed for computed tomography applications were administered through 1.1 and 1.3 mm large peripheral vein catheters into a vein phantom with room temperature and with pre-heating of the agents at 37 degrees C using a power injector. Each injection applied 40 ml of contrast medium at a flow rate of four to eight ml/s. The iodine concentration of Iopromide, Iomeprol, and Iodixanol varied between 300 and 400 mg iodine per cc. The power injector used a pressure limit of 21 bar. For each experiment, the maximum iodine deliver rate was calculated from the highest possible flow rate recorded. RESULTS: Larger vein catheters and the higher contrast temperature yielded the highest flow rates. With the higher iodine concentrations, viscosity limited the injection speed of the achievable pressure limit. The highest iodine delivery rate was 2560 mg/s, using an agent with 320 mg/ml iodine content. With the more concentrated agent, a maximal iodine delivery rate of 2400 mg/s was achieved. CONCLUSION: Very high iodinated contrast agent concentrations do not increase the iodine delivery rate of rapid peripheral intravenous injections, since the high viscosity of such agents causes the injection pressure to increase more than the higher iodine concentration would compensate for. With lower injection velocities, the higher viscosity of highly concentrated contrast agents may remain without practical consequences.

Contrast Media↗

PubMed2004

[Virtual MR endoscopy of the ventricles prior to neurosurgical interventional endoscopy -- evaluation of different presentation techniques].

PURPOSE: In the past, virtual endoscopies have been performed for planning of endoscopic interventions or for diagnostic purposes in various organ systems with increasing frequency. This study evaluates the ability of virtual ventricular endoscopy to depict anatomical structures and the use for planning of real endoscopy. MATERIALS AND METHODS: In a prospective study, 4 volunteers and 8 patients were examined with MRI. In 3 of the patients endoscopy was performed by our neurosurgeons thereafter. The calculation of the virtual endoscopy was based on 1 mm sagittal T2-weighted images. Comparison of surface rendering and volume rendering was made by means of video sequencing of individual views, and these were compared with the intraoperative endoscopic videos concerning the depictability of anatomical landmarks. RESULTS: The reconstructions using volume rendering were more significant and easier to calculate than those based on surface rendering. Virtual endoscopy in the transparent mode allowed visualization of hazardous structures outside the ventricular system such as the basilar artery tip. Transparent 3D images of the ventricles gave a good overview on the depicted structures and enabled a better orientation during the virtual camera flight than surface rendered views. CONCLUSION: MR-based virtual endoscopy of the ventricular system can be obtained on the basis of surface- and volume-rendered views of sagittal T2-weighted thin sections. Preoperative utilization of this method simplifies the planning of endoscopy by visualization of anatomical structures.

Brain Diseases↗

PubMed2004

Comparison of different cardiac MRI sequences at 1.5 T/3.0 T with respect to signal-to-noise and contrast-to-noise ratios - initial experience.

PURPOSE: To compare image quality, signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of different MRI sequences for cardiac imaging at 1.5 T and 3.0 T in volunteers. MATERIAL AND METHODS: 10 volunteers (5 male, 5 female) with a mean age of 33 years (+/- 8) without any history of cardiac diseases were examined on a GE Signa 3.0 T and a GE Signa 1.5 T TwinSpeed Excite (GE Medical Systems, Milwaukee, WI, USA) scanner using a 4-element phased array surface coil (same design) on the same day. For tissue characterization ECG gated Fast Spinecho (FSE) T (1)- (Double IR), T (1)-STIR (Triple IR) and T (2)-weighted sequences in transverse orientation were used. For functional analysis a steady state free precession (SSFP - FIESTA) sequence was performed in the 4-chamber, 2-chamber long axis and short axis view. The flip angle used for the SSFP sequence at 3.0 T was reduced from 45 degrees to 30 degrees to keep short TR times while staying within the pre-defined SAR limitations. All other sequence parameters were kept constant. RESULTS: All acquisitions could successfully be completed for the 10 volunteers. The mean SNR 3.0 T compared to 1.5 T was remarkably increased (p < 0.05) for the T (2) - (160 % SNR increase), the STIR-T (1)- (123 %) and the T (1)- (91 %) weighted FSE. Similar results were found comparing CNR at 3.0 T and 1.5 T. The mean SNR achieved using the SSFP sequences was more than doubled by 3.0 T (150 %), but did not have any significant effect on the CNR. The image quality at 3.0 T did not appear to be improved, and was considered to be significantly worse when using SSFP sequences. Artefacts like shading in the area of the right ventricle (RV) were found to be more present at 3.0 T using FSE sequences. After a localized shim had been performed in 5/10 volunteers at the infero-lateral wall of the left ventricle (LV) with the SSFP sequences at 3.0 T no significant increase in artefacts could be detected. CONCLUSIONS: In all cardiac FSE sequences, SNR and CNR at 3.0 T were found to be increased compared to 1.5 T without any major changes of the sequence parameters. The adjusted SSFP sequences fulfilled the expected increase in SNR at 3.0 T but showed no increase in CNR. On the contrary, the overall image quality did not change or was even found to be significantly lower for the SSFP and the FSE sequences at the free wall of the RV. Nevertheless, the results are encouraging for the use of 3.0 T for cardiac tissue characterization and new applications with progressing use of parallel imaging.

Adult↗

PubMed2004

[Differential diagnosis of intraconal orbital masses using high-resolution MRI with surface coils in 78 patients].

PURPOSE: Over the last decade, MRI has become the standard procedure for the diagnosis of orbital masses. Purpose of the study was to evaluate criteria for differential diagnosis for intraconal masses on MRI in a large patient group. MATERIAL AND METHODS: In a retrospective study, MR examinations of 78 patients with intraconal masses were evaluated. All examinations were performed using surface coils for high spatial resolution. Signal behavior on T2-WI and T1-WI before and after contrast application as well as further tumor characteristics (i. e., shape, size, position, delineation and infiltration) were evaluated. Every diagnosis was proven by histopathological results from extirpation (n = 18) or biopsy (n = 22), or confirmed by other imaging modalities (n = 13) or clinical course (n = 25). RESULTS: Different tumor characteristics are helpful in the differentiation between cavernous hemangioma, lymphangioma, varices, AV malformations and solid tumors. Due to overlapping in the imaging appearance, the differentiation between inflammatory pseudotumor, lymphoma and orbital metastasis was more difficult. CONCLUSION: While high resolution MRI using surface coils allows differentiation between the typical vascular tumors, the differentiation between solid tumors is more difficult. Thus, a histopathologic verification of the diagnosis is necessary in solid tumors.

Adolescent↗

PubMed2004

[Value of various MR sequences using 1.5 and 3.0 Tesla in analyzing cartilaginous defects of the patella in an animal model].

PURPOSE: Comparison of MRI and macropathologic evaluation using various sequences and field strengths in the detection, localization and measurement of cartilage defects in an animal model. MATERIALS AND METHODS: After open creation of retropatellar cartilage defects of various widths, depths and locations in 8 cadaveric sheep knee joints, the knees were examined using a fat-suppressed (FS), proton density-weighted (PD) fast spin echo (FSE), and 2D and 3D gradient echo (GE) sequences on 1.5 T and 3.0 T MR scanners. The images were analyzed by two independent radiologists in a blinded manner, by dividing the patella into 15 virtual segments. The results were correlated with the macropathologic findings with regards to location, width, and depth of the defects. RESULTS: The highest sensitivity (67.1 %), diagnostic accuracy (85.4 %), positive (87.3 %), and negative (84.7 %) predictive values in detecting defects were obtained using the 3.0 T FS-3D-GE sequence. The highest specificity (95.6 %) yielded the 3.0 T FS-2D-GE sequence, with the other sequences inferior by no more than 2.6 %. In general, FS-3D-GE sequences were superior to FS-2D-GE (3.0 T: p < 0.05; 1.5 T: p < 0.05) and especially to FS-PD-FSE sequences (3.0 T: p < 0.01; 1.5 T: p < 0.05). In determining the defects' widths, the 3.0 T FS-3D-GE sequence was superior to all other sequences (correct measurements: 50.0 %), with only slight superiority to the 1.5 T FS-3D-GE sequence (46.9 %, p > 0.05) but clear superiority to the other sequences (28.1 - 40.6 %, vs. 1.5 T FS-PD-FSE: p < 0.05, vs. other sequences: p > 0.05). To determine the defects' depths, the 1.5 T FS-3D-GE sequence was most reliable (correct measurements: 53.1 %), followed by the 3.0 T FS-3D-GE sequence (50.0 %, significance of difference: p > 0.05). CONCLUSION: In detecting cartilage defects, the field strength of 3.0 Tesla was only superior to 1.5 T MRI using fat-saturated 3D- or 2D-GE-sequences but not in fat-saturated proton density-weighted SE-sequences. In determination of depth and length of the defects, the higher field strength was not advantageous.

Adult↗