Fast Spin Echo Proton Density Research Articles

A Comparative Study on the Diagnostic Value of Conventional Spin Echo Proton Density and Fast Spin Echo Proton Density Sequences of Magnetic Resonance Imaging in Diagnosis of Meniscal Tear

Background & Objectives: Knee is the largest synovial joint in the body. Although FSE PD (fastspin echo proton density) imaging technique for the diagnosis of meniscal tear has replaced CSE PD(conventional spin echo proton density) technique in many MRI centers, several studies have questionedthe effectiveness of FSE PD technique in diagnosis of meniscal tear. In this study, the diagnostic valuesof CSE PD and FSE PD techniques in evaluation of meniscus tear are compared.Materials: In this study, using CSE PD and FSE PD techniques, MRI was performed on 67 knees ofpatients with suspected meniscal tear referring to the MRI Center of Imam Reza Hospital (Kermanshah,Iran). Diagnostic arthroscopy was also performed for all patients. The data were entered SPSS version20, and finally the results of MRI reports of the two techniques were compared in evaluation of meniscaltear taking into account the arthroscopic findings as the gold standard.Results: According to the results of this study, no significant difference was found in specificity andpositive predictive value of the two techniques. However, the sensitivity and negative predictive valueswere significantly different, in such a way that the related values were 97% and 97% in the CSE PDtechnique and 69% and 73% in the FSE PD technique, respectively.Conclusion: Due to low sensitivity and high false negative results, MRI using FSE PD technique is notrecommended as an alternative for CSE PD technique in evaluation of meniscal tear.

Forensic age estimation based on fast spin-echo proton density (FSE PD)\u2013weighted MRI of the distal radial epiphysis

Radiation exposure is a crucial factor to consider in forensic age estimation. The various magnetic resonance imaging (MRI) modalities used in forensic age estimation avoid radiation exposure. This study examined the reliability of distal radius ossification using fast spin-echo proton density (FSE PD)–weighted MRI to estimate age. Left wrist MRI findings of 532 patients aged 10–29 years were evaluated retrospectively using the five-stage system of Dedouit et al. The intra- and interobserver reliability values were κ = 0.906 and 0.869, respectively. Based on the results, the respective minimum ages estimated for stages 4 and 5 were 13.4 and 16.1 years for females, and 15.1 and 17.3 years for males; the method could not estimate an age of 18 years in any case. FSE PD MRI analysis of the distal radius epiphysis provides supportive data and can be used when evaluating the distal radius for forensic age estimation.

Comparison of proton density MRI and T2-Weighted Fast Echo for The Detection of Cervical Spinal Cord Multiple Sclerosis Lesions

Background: The prevalence of spinal cord lesions is high in multiple sclerosis particularly in the cervical cord, and their detection can assist in both the diagnosis and follow-up of the patients. For spinal multiple sclerosis, MRI is considered the first line investigation.
 Objective: To evaluate the value of sagittal 1.5 Tesla proton density-fast spin echo (PD-FSE) MRI in the detecting and increasing conspicuity of multiple sclerosis lesions in cervical cord in comparison with sagittal T2 fast spin-echo (T2-FSE) MRI.
 Patients and Methods: A cross sectional study carried out from 3rd of January 2017 to 1st of January 2018 in the MRI department of Al-Imamein Al-Kadhimein Medical City, and included 60 selected patients with a known diagnosis of multiple sclerosis. All patients were examined with 1.5 T sagittal PD-FSE, T2-FSE and axial gradient recalled-echo (GRE) MRI.
 Results: Sixty patients with cervical multiple sclerosis were enrolled in the study, 146 (100%) lesions were detected by PD-FSE imaging, while T2 detected 105 (71.9%), 41 more lesions (28%) were detected by PD-FSE imaging, (P-value <0.001). All extra lesions were confirmed on axial imaging. In 13 patients (21.6%) one lesion or more had been detected on sagittal PD-FSE imaging while on sagittal T2-FSE imaging, no lesion were detected. On PD-FSE imaging, 17 long lesions were detected in 16 patients (26.7%) while 7 long lesions in 7 patients (11.7%) were detected by T2-FSE imaging. So, in 9 patients (16.7%) 10 lesions were detected as long in PD-FSE while short lesion in T2– FSE, the detection of long lesions by PD-FSE was significantly higher than in T2– FSE (100% vs 71.9% with p- value of 0.002). The mean lesion contrast to cord ratio was significantly higher in PD-FSE as compared to T2-FSE (PD-FSE, 79±2.0, against T2-FSE, 61± 2.6; P-value <0.001).
 Conclusion: Sagittal proton density was more efficient and more accurate in the detection of cervical cord lesions than sagittal T2-FSE sequence, when used in conjunction with sagittal T2-FSE; it can raise the diagnostic assurance via improving the visualization of the lesions.

Longitudinal evidence for anterograde trans-synaptic degeneration after optic neuritis.

In multiple sclerosis, microstructural damage of normal-appearing brain tissue is an important feature of its pathology. Understanding these mechanisms is vital to help develop neuroprotective strategies. The visual pathway is a key model to study mechanisms of damage and recovery in demyelination. Anterograde trans-synaptic degeneration across the lateral geniculate nuclei has been suggested as a mechanism of tissue damage to explain optic radiation abnormalities seen in association with demyelinating disease and optic neuritis, although evidence for this has relied solely on cross-sectional studies. We therefore aimed to assess: (i) longitudinal changes in the diffusion properties of optic radiations after optic neuritis suggesting trans-synaptic degeneration; (ii) the predictive value of early optic nerve magnetic resonance imaging measures for late optic radiations changes; and (iii) the impact on visual outcome of both optic nerve and brain post-optic neuritis changes. Twenty-eight consecutive patients with acute optic neuritis and eight healthy controls were assessed visually (logMAR, colour vision, and Sloan 1.25%, 5%, 25%) and by magnetic resonance imaging, at baseline, 3, 6, and 12 months. Magnetic resonance imaging sequences performed (and metrics obtained) were: (i) optic nerve fluid-attenuated inversion-recovery (optic nerve cross-sectional area); (ii) optic nerve proton density fast spin-echo (optic nerve proton density-lesion length); (iii) optic nerve post-gadolinium T1-weighted (Gd-enhanced lesion length); and (iv) brain diffusion-weighted imaging (to derive optic radiation fractional anisotropy, radial diffusivity, and axial diffusivity). Mixed-effects and multivariate regression models were performed, adjusting for age, gender, and optic radiation lesion load. These identified changes over time and associations between early optic nerve measures and 1-year global optic radiation/clinical measures. The fractional anisotropy in patients' optic radiations decreased (P = 0.018) and radial diffusivity increased (P = 0.002) over 1 year following optic neuritis, whereas optic radiation measures were unchanged in controls. Also, smaller cross-sectional areas of affected optic nerves at 3 months post-optic neuritis predicted lower fractional anisotropy and higher radial diffusivity at 1 year (P = 0.007) in the optic radiations, whereas none of the inflammatory measures of the optic nerve predicted changes in optic radiations. Finally, greater Gd-enhanced lesion length at baseline and greater optic nerve proton density-lesion length at 1 year were associated with worse visual function at 1 year (P = 0.034 for both). Neither the cross-sectional area of the affected optic nerve after optic neuritis nor the damage in optic radiations was associated with 1-year visual outcome. Our longitudinal study shows that, after optic neuritis, there is progressive damage to the optic radiations, greater in patients with early residual optic nerve atrophy, even after adjusting for optic radiation lesions. These findings provide evidence for trans-synaptic degeneration.

Proton Density MRI Increases Detection of Cervical Spinal Cord Multiple Sclerosis Lesions Compared with T2-Weighted Fast Spin-Echo.

There is a paucity of literature that supports the Consortium of Multiple Sclerosis Centers guideline that proton density MR imaging is a core spinal cord sequence. We hypothesized that proton density fast spin-echo imaging is superior to T2 fast spin-echo MR imaging for the detection of cervical cord MS lesions. This study compared the detection rate and conspicuity of cervical cord MS lesions on sagittal 1.5T proton density fast spin-echo and T2 fast spin-echo MR imaging. One hundred consecutive patients with MS imaged with 1.5T sagittal proton density fast spin-echo and T2 fast spin-echo cervical cord MR imaging between September 2012 and October 2013 were retrospectively included. The number of MS lesions detected on each sequence was recorded; conspicuity was assessed quantitatively with the lesion-to-cord contrast ratio and lesion-contrast-to-noise ratio. Statistical analysis was performed by using the Wilcoxon signed rank test. Seventy-eight patients had MS cord lesions detected. Proton density fast spin-echo imaging detected a greater number of lesions (n = 181) compared with T2 fast spin-echo imaging (n = 137, P < .001). Fifteen patients (19%) with abnormal findings on proton density fast spin-echo imaging had normal findings on T2 fast spin-echo imaging; no patient with abnormal T2 fast spin-echo imaging findings had normal proton density fast spin-echo imaging findings. Although proton density fast spin-echo and T2 fast spin-echo imaging had similar lesion-to-cord contrast ratios (proton density fast spin-echo, 0.32 ± 0.01, versus T2 fast spin-echo, 0.33 ± 0.01; P = .43), proton density fast spin-echo had greater lesion-contrast-to-noise ratio (proton density fast spin-echo, 82 ± 3.0, versus T2 fast spin-echo, 64 ± 2.6; P < .001). Proton density fast spin-echo imaging is superior to T2 fast spin-echo MR imaging for the detection of cervical cord MS lesions. Proton density fast spin-echo detects cord lesions in patients in whom T2 fast spin-echo findings appear normal. This study forms the evidentiary base for the current Consortium of Multiple Sclerosis Centers guideline that proton density imaging is a core spinal cord sequence.

A comparative MRI study for white matter hyperintensities detection: 2D-FLAIR, FSE PD 2D, 3D-FLAIR and FLAIR MIP

The main objective of this study was to not only determine the most appropriate sequence for the analysis of white matter hyperintensities (WMH) on MRI but also to confirm the advantage of three-dimensional (3D) acquisition, as it has been suggested in previous studies, and to test the convenience of using maximum intensity projection (MIP) algorithms on 3D-fluid-attenuated inversion-recovery (FLAIR) images for a quicker evaluation of brain MR studies. The number of WMH was compared in 40 patients and a control group of 10 volunteers using 4 different imaging modalities: two dimensional (2D)-FLAIR, 2D fast spin echo proton density (FSE PD), 3D-FLAIR and FLAIR MIP. Four experienced radiologists took part in the imaging analysis. All studies were performed on a 1.5-T whole-body MR unit. A statistically significant difference between the number of lesions detected on 3D acquisitions (FLAIR CUBE® or FLAIR MIP sequences) compared with those on 2D-FLAIR or 2D FSE PD was demonstrated. There is no significant difference between 3D-FLAIR and FLAIR MIP, therefore both of them can be used with similar results. 3D-FLAIR sequences should replace conventional 2D-FLAIR and/or FSE PD sequences in the MR acquisition protocol when WMH are suspected. MIP reformat algorithms are less time consuming, therefore these can also be used to simplify the detection. 3D sequences are superior for WMH depiction. Moreover, MIP algorithms allow easier analyses with similar results.

Meniscal tears: comparison of the conventional spin-echo and fast spin-echo techniques through image processing

BackgroundConventional spin-echo (PD-CSE) and fast spin-echo (PD-FSE) techniques are frequently used to detect meniscal tears. However, the time delay for imaging with PD-CSE has resulted in its replacement with faster techniques, such as proton density fast spin-echo (PD-FSE), which has become a frequent tool at most diagnostic centres.Qualitative analysis shows that the PD-CSE technique is more sensitive, but other authors have not found significant differences between the aforementioned techniques. Therefore, we performed a quantitative analysis in this study that aims to measure differences in the quality of the images obtained with both techniques.MethodsWe compared the PD-CSE and PD-FSE techniques by quantitatively analysing the obtained proton density images: the area shown, as well as the brightness and lesion contrast of the obtained image.A set of 100 images from 50 patients thought to contain meniscal tears of the knee were selected. These 100 images were obtained from all individuals using both the PD-CSE and PD-FSE techniques. The images were processed using software developed in Delphi. In addition to these quantifications, three physicians, who are specialists in radiology and capable of analysing magnetic resonance (MR) images of the musculoskeletal system, qualitatively analysed the diagnostic sensitivity of both techniques.ResultsOn average, samples obtained via the PD-CSE technique contained 22% more pixels in the lesion area. The contrast differed by 28%, and the brightness differed by 31%. The two techniques were correlated using Student’s t-test, which showed a statistically significant difference. The specialists detected meniscal tears in 30 of the images obtained via the PD-CSE technique, while only 72% of these cases were detected via the PD-FSE technique.ConclusionsThe PD-CSE technique was shown to be superior to PD-FSE for all of the evaluated properties, making its selection preferable.

Automated prostate segmentation in whole-body MRI scans for epidemiological studies

The whole prostatic volume (PV) is an important indicator for benign prostate hyperplasia. Correlating the PV with other clinical parameters in a population-based prospective cohort study (SHIP-2) requires valid prostate segmentation in a large number of whole-body MRI scans. The axial proton density fast spin echo fat saturated sequence is used for prostate screening in SHIP-2. Our automated segmentation method is based on support vector machines (SVM). We used three-dimensional neighborhood information to build classification vectors from automatically generated features and randomly selected 16 MR examinations for validation. The Hausdorff distance reached a mean value of 5.048 ± 2.413, and a mean value of 5.613 ± 2.897 compared to manual segmentation by observers A and B. The comparison between volume measurement of SVM-based segmentation and manual segmentation of observers A and B depicts a strong correlation resulting in Spearman’s rank correlation coefficients (ρ) of 0.936 and 0.859, respectively. Our automated methodology based on SVM for prostate segmentation can segment the prostate in WBI scans with good segmentation quality and has considerable potential for integration in epidemiological studies.

MTR and In-vivo 1H-MRS studies on mouse brain with parkinson’s disease

The aim of this study was to investigate whether the changes in the magnetization transfer ratio (MTR) histogram are related to specific characteristics of Parkinson’s disease (PD) and to investigate whether the MTR histogram parameters are associated with neurochemical dysfunction by performing in vivo proton magnetic resonance spectroscopy (1H-MRS). MTR and in vivo1H-MRS studies were performed on control mice (n = 10) and 1-methyl-1,2,3,6-tetrahydropyridine intoxicated mice (n = 10). All the MTR and in vivo1H-MRS experiments were performed on a 9.4 T MRI/MRS system (Bruker Biospin, Germany) using a standard head coil. The protondensity fast spin echo (FSE) images and the T2-weighted spin echo (SE) images were acquired with no gap. Outer volume suppression (OVS), combined with the ultra-short echo-time stimulated echo acquisition mode (STEAM), was used for the localized in-vivo1H-MRS. The quantitative analysis of metabolites was performed from the 1H spectra obtained in vivo on the striatum (ST) by using jMRUI (Lyon, France). The peak height of the MTR histograms in the PD model group was significantly lower than that in the control group (p < 0.05). The midbrain MTR values for volume were lower in the PD group than the control group(p < 0.05). The complex peak (Glx: glutamine+glutamate+ GABA)/creatine (Cr) ratio of the right ST in the PD group was significantly increased as compared to that of the control group. The present study revealed that the peak height of the MTR histogram was significantly decreased in the ST and substantia nigra, and a significant increase in the Glx/Cr ratio was found in the ST of the PD group, as compared with that of the control group. These findings could reflect the early phase of neuronal dysfunction of neurotransmitters.

Meniscal tear evaluation. Comparison of a conventional spin-echo proton density sequence with a fast spin-echo sequence utilizing a 512×358 matrix size

To determine the sensitivities, specificities, and receiver-operating characteristics (ROCs) for sagittal conventional spin-echo proton density (SE-PD) and fast spin-echo proton density (FSE-PD) sequences in the diagnosis of meniscal tears when compared to arthroscopic findings utilizing increased FSE matrix acquisition size. Magnetic resonance imaging (MRI) studies of 97 knees (194 menisci) were independently and prospectively interpreted by two experienced musculoskeletal radiologists over four separate readings at least 3 weeks apart. Readings 1 and 2 included images in all three planes in accordance with the standard protocol with either a SE or FSE sagittal PD, at readings 3 and 4 just the SE or FSE sagittal PD sequences were reported. The FSE sequence was acquired with an increased matrix size, compared to the SE sequence, to provide increased resolution. Menisci were graded for the presence of a tear and statistical analysis to calculate sensitivity and specificity was performed comparing to arthroscopy as the reference standard. ROC analysis for the diagnosis of meniscal tears on the SE and FSE sagittal sequences was also evaluated. Reader concordance for the SE and FSE sequences was calculated. Sixty-seven tears were noted at arthroscopy; 60 were detected on SE and 56 on FSE. The sensitivity and specificity for SE was 90 and 90%, and for FSE was 84 and 94%, respectively, with no significant difference. ROC analysis showed no significant difference between the two sequences and kappa values demonstrated a higher level of reader agreement for the FSE than for the SE reading. Use of a FSE sagittal PD sequence with an increased matrix size provides comparable performance to conventional SE sagittal PD when evaluating meniscal disease with a modern system. The present study indicates an increased level of concordance between readers for the FSE sagittal sequence compared to the conventional SE.

MRI of prostate brachytherapy seeds at high field: A study in phantom

Postimplant evaluation of prostate brachytherapy using magnetic resonance imaging (MRI) at 1.5 T has met with some difficulties due to the uncertainty associated with seed localization despite the excellent anatomical delineation this imaging modality can achieve. Seeds in vascularized regions or outside the prostate, where signal heterogeneity or drop off can obscure their position, can be difficult to identify. The increase in SNR available at 3.0 T offers the potential to improve these issues with visualization. However, before moving directly to in vivo studies, it is important to investigate the effects of artifact size on the ability to localize multiple seeds in close proximity. These artifacts are of extra concern at higher field because of the increased induced field distortions surrounding the seeds. A single prostate brachytherapy seed (IMC6711, OncoSeed) and arrays of seed pairs were suspended in a porcine gel medium and imaged on 1.5 and 3 T MRI scanners for comparison. Two basic acquisition techniques utilized in a wide array of clinical sequences [spin-echo based and gradient-echo (GE) based] were investigated for the types of artifacts they produce, and their dependence on field. Analysis of the resulting voids was performed to determine the relative size of seeds as seen on the images, as well as the ability to distinguish seeds at close proximity. The seed voids at 3 T were only slightly larger than those obtained at 1.5 T (0.5 mm longer and wider) when using a spin-echo type sequence. For this work, the authors used a proton density fast spin-echo (FSE) sequence. These results are promising for the use of 3 T imaging for postimplant evaluation since the SNR will increase by roughly a factor of 2 with only a limited corresponding increase in artifact size. The minimum separation of the seeds to be completely distinguished using void analysis increased from between 1.5 and 3 mm to between 3 and 4.5 mm when going from 1.5 to 3 T FSE imaging. The minimum separation of the seeds for GE at the demonstration TE of 11 ms was found to be between 3 and 4.5 mm for 1.5 T and between 4.5 and 6 mm for 3 T. These GE artifact dimensions will scale down with TE and, as this happens, approach the dimensions of the FSE artifacts given above.

Comparison of spin echo T1-weighted sequences versus fast spin-echo proton density-weighted sequences for evaluation of meniscal tears at 1.5 T

At our institution, fast spin-echo (FSE) proton density (PD) imaging is used to evaluate articular cartilage, while conventional spin-echo (CSE) T1-weighted sequences have been traditionally used to characterize meniscal pathology. We sought to determine if FSE PD-weighted sequences are equivalent to CSE T1-weighted sequences in the detection of meniscal tears, obviating the need to perform both sequences. We retrospectively reviewed the records of knee arthroscopies performed by two arthroscopy-focused surgeons from an academic medical center over a 2-year period. The preoperative MRI images were interpreted independently by two fellowship-trained musculoskeletal radiologists who graded the sagittal CSE T1 and FSE PD sequences at different sittings with grades 1-5, where 1 = normal meniscus, 2 = probable normal meniscus, 3 = indeterminate, 4 = probable torn meniscus, and 5 = torn meniscus. Each meniscus was divided into an anterior and posterior half, and these halves were graded separately. Operative findings provided the gold standard. Receiver operating characteristic (ROC) analysis was performed to compare the two sequences. There were 131 tears in 504 meniscal halves. Using ROC analysis, the reader 1 area under curve for FSE PD was significantly better than CSE T1 (0.939 vs. 0.902, >95% confidence). For reader 2, the difference met good criteria for statistical non-inferiority but not superiority (0.913 for FSE PD and 0.908 for CSE T1; >95% non-inferiority for difference at most of -0.027). FSE PD-weighted sequences, using our institutional protocol, are not inferior to CSE T1-weighted sequences for the detection of meniscal tears and may be superior.

MR Imaging of the Midfoot and Forefoot

AbstractMR imaging is the diagnostic modality of choice for the evaluation of traumatic, inflammatory and neoplastic processes affecting the midfoot and forefoot soft tissue structures including muscles, ligaments, and tendons. MR imaging is also valuable in the diagnosis of occult bony trauma, stress reaction or fractures, and osteomyelitis. Exquisite contrast resolution, noninvasiveness, and multiplanar capabilities are unique features that make MR imaging a powerful diagnostic technique. The authors employ a basic protocol using T1‐weighted, fast spin echo proton density with and without frequency‐selective fat saturation, and fast spin echo T2‐weighted sequences as well as short‐tau inversion recovery (STIR) imaging. Additional imaging following intravenous gadolinium administration is indicated when osteomyelitis and neoplastic processes are suspected. Post‐contrast fat‐suppressed T1‐weighted sequences are necessary if intravenous or intra‐articular gadolinium is utilized.

3.0-T MRI of Meniscal Tears

The sensitivity and specificity of 3.0-T MRI of the knee for meniscal tears have not been specifically assessed. We undertook a retrospective review of 100 consecutive MR examinations of the knee followed by arthroscopy to evaluate the sensitivity and specificity of 3.0-T MRI compared with arthroscopy in the detection of meniscal tears. Two experienced musculoskeletal radiologists retrospectively reviewed MR scans of the knees of 100 patients who underwent consecutive knee arthroscopic procedures after MRI examinations. Interpretations were performed by consensus review with the reviewers blinded to arthroscopic results at the time of consensus review. All patients underwent complete MRI of the knee on a 3.0-T unit. All patients underwent fast spin-echo proton density sagittal imaging at 2-mm slice thickness. Fat-saturated fast spin-echo T2 axial, coronal, and sagittal imaging and T1 coronal imaging also were performed. All 100 patients underwent arthroscopy, and the results were compared with MR interpretations. Consensus retrospective review of the 100 knee MR examinations revealed 111 meniscal tears. Four meniscal tears seen on arthroscopy were not seen on MR examination. There were three false-positive MR interpretations of meniscal tear compared with arthroscopy. In this study, the sensitivity of MRI in the detection of meniscal tears was 96%, and the specificity was 97%. MRI of the knee at 3.0 T is sensitive and specific compared with arthroscopy in the detection of meniscal tears. Findings at 3.0 T compare favorably with results at 1.5-T or lower field strength.

MAGNETIC RESONANCE IMAGING OF PELVIC MUSCULOSKELETAL AND GENITOURINARY ANATOMY IN PATIENTS BEFORE AND AFTER COMPLETE PRIMARY REPAIR OF BLADDER EXSTROPHY

We characterize pelvic soft tissue and bony anatomy of patients before and after complete primary repair of exstrophy (CPRE). We evaluated 15 measurements on pelvic magnetic resonance imaging (MRI) in patients who underwent CPRE without osteotomy at our institution from 1996 to 2004. MRI protocols included axial, sagittal and coronal fast spin echo proton density sequences. Measurements were compared before and after CPRE using a paired t test, and between patients after CPRE, and age and gender matched controls using linear regression adjusting for the matched case-control groups. Patients older than 3 years with continent intervals longer than 3 hours after CPRE were compared to age and gender matched controls using linear regression. A total of 29 MRIs in 18 patients with exstrophy were available for analysis. Median patient age at postoperative MRI was 25 months (range 4 to 36). The configuration of the post-CPRE pelvis was significantly different from that of controls in all parameters measured including wider symphyseal diastasis (34.5 mm vs less than 1 mm) and more obtuse iliac wing (121 degrees vs 98 degrees), puborectalis (94 degrees vs 49 degrees) and ileococcygeus angles (111 degrees vs 98 degrees ). The anatomy of continent patients after CPRE was not significantly different from that of controls in most parameters measured. Comparison of the pelvic anatomy in patients before and after CPRE suggests that after CPRE patients have parameters that more closely approximate, but are still significantly different, from those of control patients. Patients with greater than 3-hour continent intervals after CPRE have anatomic parameters most similar to those of age matched controls.

Contrast-enhanced high-resolution magnetic resonance imaging of autologous cartilage implants of the knee joint

Over the past decade, a number of interventions for durable cartilage repair have emerged. Magnetic resonance (MR) tomography is an excellent noninvasive method for monitoring cartilage repair tissues throughout the postsurgical period. However, evaluating cartilage morphology after matrix-based autologous cartilage implantation (ACI) with MR imaging (MRI) still remains a challenge. In this study, we combined a high-resolution cartilage-sensitive fast-spin echo (FSE) sequence with intravenous application of a contrast agent for enhancing synovial fluid. Two independent musculoskeletal radiologists interpreted the pictures for the thickness, length and surface of the cartilage implants. A multivariate two-way analysis of variance with two repeated measures was performed and showed that evaluation of cartilage implant morphology was significantly improved after the application of gadodiamide on proton density FSE images. Contrast-enhanced MRI of articular cartilages is a promising technique in the postoperative follow-up of patients after ACI.

Short tau inversion recovery and proton density-weighted fat suppressed sequences for the evaluation of osteoarthritis of the knee with a 1.0 T dedicated extremity MRI: development of a time-efficient sequence protocol

Aim of this study was to develop a time-efficient sequence protocol for a 1.0 T dedicated MR system to be used for whole-organ scoring of osteoarthritis (OA). Thirty-four knees were examined using a protocol that included fat suppressed fast spin echo proton density weighted sequences (PDFS) in three planes plus a coronal STIR sequence. Two radiologists scored each knee by consensus for five OA features. In separate sessions, all knees were scored using three different combinations of sequences: (1) all four sequences (reference protocol, 16 min 31 s scanning time), (2) three PDFS sequences without STIR ("No STIR", 12 min 25 s scanning time) and (3) sagittal and axial PDFS sequences plus a coronal STIR sequence ("No PDFS", 11 min 49 s scanning time). Agreement of the readings using both subsets of sequences compared to the reference protocol was evaluated using weighted kappa statistics. kappa-coefficients showed good or excellent agreement for both sequence subsets in comparison to the reference protocol for all assessed features. kappa-coefficients for No PDFS/No STIR: bone marrow abnormalities (0.74/0.67), subarticular cysts (0.84/0.63), marginal osteophytes (0.77/0.71), menisci (0.75/0.79), tibial cartilage (0.71/0.78). Optimization of sequence protocols consisting of three sequences results in time savings and cost efficiency in imaging of knee OA without loss of information over a more time consuming protocol.

Meniscal tears: role of axial MRI alone and in combination with other imaging planes.

The purpose of this study was to determine the reliability of standard axial MR images alone in the diagnosis of meniscal tears of the knee and in combination with other imaging planes. Sixty-two patients (55 men, seven women; age range, 23-68 years) with a prior MRI examination who underwent arthroscopic surgery of the knee during a 1-year period were included in the study group. Images were independently reviewed for identification of meniscal tears by two musculoskeletal radiologists blinded to arthroscopic findings. Sequences for meniscal evaluation included axial fat-saturated fast spin-echo proton density, coronal fat-saturated fast spin-echo proton density, and sagittal fast spin-echo proton density with 4- to 5-mm slice thicknesses. Imaging groups for evaluation were axial, coronal, sagittal, axial and sagittal, axial and coronal, and coronal and sagittal. Observers reported a confidence level for the presence or absence of meniscal tear in all imaging groups based on a 5-point scale. Statistical analysis considered medial and lateral menisci separately. Forty patients had medial meniscal tears, and 16 had lateral meniscal tears at arthroscopy. For medial and lateral meniscal tears, the accuracy (79% and 71%, respectively) of imaging in the axial plane was comparable to other imaging groups but the mean confidence levels (2.82 and 3.00, respectively) were low. In one patient, the axial plane alone correctly showed that no tear was present. No statistically significant difference was observed between imaging plane groups of both menisci in the diagnosis of meniscal tears (p > 0.05). The axial plane increased the accuracy of sagittal and coronal planes of lateral meniscus when combined. In standard knee MRI examinations, the axial imaging plane may be valuable for the detection and characterization of meniscal tears.

Optimal positioning for MRI of the distal biceps brachii tendon: flexed abducted supinated view.

Imaging was performed on a 1.5-T MRI scanner (Signa Horizon LX, release 9.0, General Electric Medical Systems) with either the extremity coil or the dedicated shoulder phased array coil. In general, it was preferable for the patient to lie prone for these views. The shoulder was abducted 180°, with the arm beside the head. The elbow was flexed to 90°, with the forearm supinated, thumb up, and a shoulder phased array coil was placed around the elbow (Fig. 1). The position is referred to in this article as the flexed abducted supinated view, but usually in our practice it is termed the “FABS view,” meaning the flexed elbow with the shoulder abducted and the forearm in supination view. We initially performed a three-plane localizer, with either three or five images in the axial, sagittal, and coronal planes. The coronal localizer images (sagittal elbow anatomy) were used to plan the sequences along the long axis of the distal biceps brachii tendon (along the line of the tendon if it is visible). If the tendon was not clearly seen on the localizer images, the series was planned nearly perpendicular to the radius, which was always clearly seen (Fig. 2). The normal flexed abducted supinated view showed the full length of the tendon (Fig. 3). Images in axial, and in some cases sagittal, planes were then also obtained with the shoulder in abduction and the elbow extended in the overhead position. It is also possible to obtain the axial and sagittal images with the arm by the side. Series with and without fat suppression were performed (proton density fast spin echo; TR/TE, 3,000/34 or 45) along the axis of the tendon (elbow flexed) and axial to the elbow joint (elbow extended). The field of view was 15 × 15 cm, and the slice thickness was 3 or 4 mm with interslice spacing of zero. For the flexed abducted supinated view, usually 18 slices were obtained with an approximate examination time of 2 min 40 sec. Results The MR images were independently reviewed by two radiologists experienced in musculoskeletal imaging. We have imaged, using the flexed abducted supinated view, 21 symptomatic patients with possible distal biceps brachii tendon problem. In one case, both elbows were symptomatic and were imaged. These patients were 32‐81 years old (mean age, 52 years) and were imaged over the period from May 2001 to May 2003. Six asymptomatic healthy male volunteers (age range, 31‐48 years) were also imaged using both traditional sagittal and flexed abducted supinated positions. Three cases among 22 elbows in the study group exhibited normal distal biceps brachii tendons; in 14 cases, evidence of a partial tear or tendinosis of the distal biceps brachii tendon (Figs. 4 and 5) was present; in four cases, a complete tear (Fig. 6) was present; and in one case, an intact repaired complete tear was seen. In all cases, the full length of the biceps brachii tendon from musculotendinous junction to insertion on the radial tuberosity could be shown in one or, at most, two sections. In the 13 cases in which sagittal series were also performed, a single section less commonly ( n = 8) showed the full tendon in one or two sections. In four of these six asymptomatic volunteer evaluations, the flexed abducted supinated view showed the complete length of the tendon in one section; in the other two cases, it was seen in two sections. In the sagittal series of the healthy volunteers, the full tendon was seen in one section in only two cases.

Comparison of surface coil and knee coil for evaluation of the patellar cartilage by MR imaging

Purpose: The aim of this work was to compare the knee coil and the surface coil for the visualisation of the patellar cartilage. Materials and methods: In 28 patients (17 women, 11 men) with an average age of 40 years (range 14–76) with knee pain MR was performed. Transverse images were obtained using a fast spin echo proton density weighted sequence on a Philips Gyroscan Intera 1.5 T clinical system. Transverse images were obtained at the level of the patellar cartilage using both the surface and the knee coil. All images were evaluated by consensus of two radiologists. They evaluated a number of quality criteria on a 4-point scale. Criteria for artefacts were also graded on a 4-point scale. Results: For the visualisation of fluid there was no significant difference between the knee coil and the surface coil ( P=0.021). For all other criteria regarding image quality and presence of imaging artefacts there was a significant difference between both coils ( P<0.001) with the surface coil obtaining the better result. Conclusion: The use of the surface coil in the visualisation of the patellar cartilage can be recommended at knee MR.