Faculty Bibliography

OBJECTIVE:The purpose of this study was to determine whether the use of radial reformatted images could improve the diagnostic performance of a 3D fast spin-echo (FSE) sequence for detecting surgically confirmed cartilage lesions within the knee joint. MATERIALS AND METHODS/METHODS:An MRI examination consisting of five 2D FSE sequences and a sagittal 3D FSE sequence was performed at 3 T on the knee joint of 150 patients who underwent subsequent knee arthroscopy, which included grading of the articular cartilage. Conventional axial, sagittal, and coronal reformatted images and radial reformatted images were created from the 3D FSE source data. Two musculoskeletal radiologists independently used the 2D FSE sequences, the 3D FSE sequence with conventional reformatted images only, and the 3D FSE sequence with both radial and conventional reformatted images at three separate sessions to grade each articular surface of the knee joint. McNemar tests were used to compare diagnostic performance for detecting cartilage lesions using arthroscopy as the reference standard. RESULTS:The 3D FSE sequence with radial and conventional reformatted images had higher sensitivity (p < 0.001) and similar specificity (p = 0.73) to the 2D FSE sequences for detecting cartilage lesions and higher sensitivity (p < 0.001) and specificity (p = 0.002) than the 3D FSE sequence with conventional reformatted images for detecting cartilage lesions. The 3D FSE sequence with conventional reformatted images had similar sensitivity (p = 0.93) and lower specificity (p = 0.005) than did the 2D FSE sequences for detecting cartilage lesions. CONCLUSION/CONCLUSIONS:A 3D FSE sequence had improved diagnostic performance compared with 2D FSE sequences for detecting cartilage lesions within the knee joint but only when using both radial and conventional reformatted images for cartilage evaluation.

OBJECTIVE:MRI findings of ischiofemoral impingement (IFI) have been described, but there is little evidence for treatment with ultrasound-guided corticosteroid injection. The purpose of this study was to evaluate the effectiveness of ultrasound-guided corticosteroid injection of the quadratus femoris muscle as a treatment of IFI syndrome and to correlate the MRI findings with injection outcome. MATERIALS AND METHODS/METHODS:The medical records of 61 consecutively registered subjects who underwent bony pelvis MRI in which either IFI or quadratus femoris edema was described in the radiology report were retrospectively reviewed. Subjects with MRI findings of IFI and clinical confirmation of pain that could be attributed to IFI were included and divided into injection and control groups based on clinical management. Control subjects had MRI findings and clinical symptoms suggestive of IFI but underwent conservative therapy rather than injection. The control patients had adequate follow-up and clinical documentation to determine their response to treatment. Quadratus femoris muscle edema, fat atrophy, and hamstring tendinopathy were graded from none to severe (grades 0-3). The ischiofemoral and quadratus femoris spaces were also measured. Clinical presentation was classified as typical, somewhat typical, or not typical of IFI. Injection effectiveness was determined by reported pain reduction assessed before, immediately after, and 2 weeks after the procedure with a standard 10-cm visual analog scale. Response to treatment was classified as good (reduction in pain level > 2), mild or partial (reduced by 1 or 2), or no improvement. For patients who did not return their 2-week postinjection pain surveys, injection effectiveness was determined by qualitative assessments found in their clinical notes. A Kruskal-Wallis rank sum test was used to compare effectiveness of injection between groups (p < 0.05). The Fisher exact test was used to evaluate for associations between each MRI finding and injection outcome. RESULTS:Of the 61 patients, 20 patients had both MRI findings and clinical confirmation of pain related to IFI. These 20 patients were included in the study. Fifteen ultrasound-guided injections were performed in seven patients, and these seven patients were included in the injection group (mean age, 47 years; range, 15-66 years); 13 patients were included in the control group (mean age, 42 years; range, 16-62 years). All seven patients in the injection group and 12 of the 13 patients in the control group were women. In the injection group, the mean width of the ischiofemoral space was 12 mm (range, 7-22 mm), and the mean width of the quadratus femoris space was 9 mm (range, 5-16 mm). The mean edema grade was 1.4 (range, 0-3); mean atrophy grade, 1.4 (range, 0-3); and mean hamstring tendinopathy grade, 1 (range, 0-2). In the control group, the mean width of the ischiofemoral space was 9 mm (range, 6-17 mm); mean quadratus femoris space width, 7 mm (range, 3-15 mm); mean edema grade, 1.9 (range, 1-3); mean atrophy grade, 1.2 (range, 0-3); and mean hamstring tendinopathy grade, 1.2 (range, 0-3). No statistical difference was seen between the two groups before treatment. Pain reduction after injection over the 2-week period was statistically significant with a mean reduction of 1.7 (range, 1-2) for the injection group and 0.8 (range, 0-2) for the control group (p < 0.01). Eleven of 15 (73%) of the injections provided good relief, and four of 15 (27%) provided mild relief. None of the 15 injections provided no relief. In the control group, four of 14 (29%) subjects had good relief, three of 14 (21%) had mild relief, and seven of 14 (50%) had no relief (p < 0.01). CONCLUSION/CONCLUSIONS:Ultrasound-guided corticosteroid injection of the quadratus femoris muscle shows promise as an effective treatment of IFI syndrome. However, larger longitudinal studies are needed to help establish the role of ultrasound-guided injection in the workup and care of patients presenting with both MRI findings and clinical findings of IFI.

Osteoarthritis is characterized by a decrease in the proteoglycan content and disruption of the highly organized collagen fiber network of articular cartilage. Various quantitative magnetic resonance imaging techniques have been developed for noninvasive assessment of the proteoglycan and collagen components of cartilage. These techniques have been extensively used in clinical practice to detect early cartilage degeneration and in osteoarthritis research studies to monitor disease-related and treatment-related changes in cartilage over time. This article reviews the role of quantitative magnetic resonance imaging in evaluating the composition and ultrastructure of the articular cartilage of the knee joint.

PURPOSE/OBJECTIVE:To optimize acquisition parameters for three dimensional fast spin-echo (3D FSE) imaging of the knee. MATERIALS AND METHODS/METHODS:The knees of eight healthy volunteers were imaged in a 3 Tesla MRI scanner using an eight-channel knee coil. A total of 146 intermediate weighted isotropic resolution 3D FSE (3D-FSE-Cube)images with varied acquisition parameter settings were acquired with an additional reference scan performed for subjective image quality assessment. Images were graded for overall quality, parallel imaging artifact severity and blurring. Cartilage, muscle, and fluid signal-to-noise ratios and fluid-cartilage contrast-to-noise ratios were quantified by acquiring scans without radio frequency excitation and custom-reconstructing the k-space data.Mixed effects regression modeling was used to determine statistically significant effects of different parameters on image quality. RESULTS:Changes in receiver bandwidth, repetition time and echo train length significantly affected all measurements of image quality (P < 0.05). Reducing band width improved all metrics of image quality with the exception of blurring. Reader agreement was slight to fair for subjective metrics, but overall trends in quality ratings were apparent. CONCLUSION/CONCLUSIONS:We used a systematic approach to optimize 3D-FSE-Cube parameters for knee imaging. Image quality was overall improved using a receiver bandwidth of 631.25 kHz, and blurring increased with lower band width and longer echo trains.

OBJECTIVES/OBJECTIVE:This study determined whether injection with hypertonic dextrose and morrhuate sodium (prolotherapy) using a pragmatic, clinically determined injection schedule for knee osteoarthritis (KOA) results in improved knee pain, function, and stiffness compared to baseline status. DESIGN/METHODS:This was a prospective three-arm uncontrolled study with 1-year follow-up. SETTING/METHODS:The setting was outpatient. PARTICIPANTS/METHODS:The participants were 38 adults who had at least 3 months of symptomatic KOA and who were in the control groups of a prior prolotherapy randomized controlled trial (RCT) (Prior-Control), were ineligible for the RCT (Prior-Ineligible), or were eligible but declined the RCT (Prior-Declined). INTERVENTION/METHODS:The injection sessions at occurred at 1, 5, and 9 weeks with as-needed treatment at weeks 13 and 17. Extra-articular injections of 15% dextrose and 5% morrhuate sodium were done at peri-articular tendon and ligament insertions. A single intra-articular injection of 6 mL 25% dextrose was performed through an inferomedial approach. OUTCOME MEASURES/METHODS:The primary outcome measure was the validated Western Ontario McMaster University Osteoarthritis Index (WOMAC). The secondary outcome measure was the Knee Pain Scale and postprocedure opioid medication use and participant satisfaction. RESULTS:The Prior-Declined group reported the most severe baseline WOMAC score (p=0.02). Compared to baseline status, participants in the Prior-Control group reported a score change of 12.4±3.5 points (19.5%, p=0.002). Prior-Decline and Prior-Ineligible groups improved by 19.4±7.0 (42.9%, p=0.05) and 17.8±3.9 (28.4%, p=0.008) points, respectively; 55.6% of Prior-Control, 75% of Prior-Decline, and 50% of Prior-Ineligible participants reported score improvement in excess of the 12-point minimal clinical important difference on the WOMAC measure. Postprocedure opioid medication resulted in rapid diminution of prolotherapy injection pain. Satisfaction was high and there were no adverse events. CONCLUSIONS:Prolotherapy using dextrose and morrhuate sodium injections for participants with mild-to-severe KOA resulted in safe, significant, sustained improvement of WOMAC-based knee pain, function, and stiffness scores compared to baseline status.

Radial trajectories facilitate high-resolution balanced steady state free precession (bSSFP) because the efficient gradients provide more time to extend the trajectory in k-space. A number of radial bSSFP methods that support fat-water separation have been developed; however, most of these methods require an environment with limited B0 inhomogeneity. In this work, high-resolution bSSFP with fat-water separation is achieved in more challenging B0 environments by combining a 3D radial trajectory with the IDEAL chemical species separation method. A method to maintain very high resolution within the timing constraints of bSSFP and IDEAL is described using a dual-pass pulse sequence. The sampling of a unique set of radial lines at each echo time is investigated as a means to circumvent the longer scan time that IDEAL incurs as a multiecho acquisition. The manifestation of undersampling artifacts in this trajectory and their effect on chemical species separation are investigated in comparison to the case in which each echo samples the same set of radial lines. This new bSSFP method achieves 0.63 mm isotropic resolution in a 5-min scan and is demonstrated in difficult in vivo imaging environments, including the breast and a knee with ACL reconstruction hardware at 1.5 T.

PURPOSE/OBJECTIVE:To determine the feasibility of using multicomponent-driven equilibrium single-shot observation of T1 and T2 (mcDESPOT) for evaluating the human knee joint at 3.0T and to investigate depth-dependent and regional-dependent variations in multicomponent T2 parameters within articular cartilage. MATERIALS AND METHODS/METHODS:mcDESPOT was performed on the knee joint of 10 asymptomatic volunteers at 3.0T. Single-component T2 relaxation time (T2single ), multicomponent T2 relaxation time for water tightly bound to proteoglycan (T2PG ) and bulk water loosely bound to the macromolecular matrix (T2BW ), and fraction of water tightly bound to proteoglycan (FPG ) were measured in eight cartilage subsections and within the superficial and deep layers of patellar cartilage. Statistical analysis was used to investigate depth-dependent and regional-dependent variations in parameters. RESULTS:There was lower (P = 0.001) T2single and T2PG and higher (P < 0.001) FPG in the deep than superficial layer of patellar cartilage. There was higher (P < 0.001) FPG on the weight-bearing surfaces than nonweight-bearing surfaces. There was higher (P < 0.001) T2single , T2PG , and T2BW on the trochlea and posterior medial and lateral femoral condyles than the patella, central medial and lateral femoral condyles, and medial and lateral tibia plateaus. CONCLUSION/CONCLUSIONS:Multicomponent T2 parameters of the articular cartilage of the human knee joint can be measured at 3.0T using mcDESPOT and show depth-dependent and regional-dependent variations.

PURPOSE/OBJECTIVE:To compare a balanced steady-state free-precession sequence with a radial k-space trajectory and alternating repetition time fat suppression (Radial-ATR) with other currently used fat-suppressed 3D sequences for evaluating the articular cartilage of the knee joint at 3.0T. MATERIALS AND METHODS/METHODS:Radial-ATR, fast spin-echo (FSE-Cube), gradient recall-echo acquired in the steady-state (GRASS), and spoiled gradient recall-echo (SPGR) sequences with similar voxel volumes and identical scan times were performed at 3.0T on both knee joints of five volunteers. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were performed for all sequences using a double acquisition method and compared using Mann-Whitney Wilcoxon tests. Radial-ATR sequences with 0.3 mm and 0.4 mm isotropic resolution were also performed on the knee joints of seven volunteers and three patients with osteoarthritis. RESULTS:Average SNR values for cartilage, synovial fluid, and bone marrow were 54.7, 153.3, and 12.9, respectively, for Radial ATR, 30.8, 44.1, and 1.9, respectively, for FSE-Cube, 13.3, 46.9, and 3.3, respectively, for GRASS, and 19.1, 8.1, and 2.1, respectively, for SPGR. Average CNR values between cartilage and synovial fluid and between cartilage and bone marrow were 98.6 and 41.8, respectively, for VIPR-ATR, 13.4 and 28.8, respectively, for FSE-Cube, 33.6 and 10.0, respectively, for GRASS, and 11.0 and 16.9, respectively, for SPGR. Radial-ATR had significantly higher (P < 0.001) cartilage, synovial fluid, and bone marrow SNR and significantly higher (P < 0.01) CNR between cartilage and synovial fluid and between cartilage and bone marrow than FSE-Cube, GRASS, and SPGR. Radial-ATR provided excellent visualization of articular cartilage at high isotropic resolution with no image degradation due to off-resonance banding artifacts. CONCLUSION/CONCLUSIONS:Radial-ATR had superior SNR efficiency to other fat-suppressed 3D cartilage imaging sequences and produced high isotropic resolution images of the knee joint which could be used for evaluating articular cartilage at 3.0T.

OBJECTIVE:The objective of our study was to retrospectively compare the MRI characteristics of surgically confirmed healed and unhealed peripheral vertical meniscal tears. MATERIALS AND METHODS/METHODS:The study group consisted of 64 patients with 86 peripheral vertical meniscal tears diagnosed on MRI who subsequently underwent knee surgery. The MRI examinations were retrospectively reviewed to assess the following tear characteristics: tear location relative to the meniscocapsular junction, tear width, tear length, tear extension through one or both surfaces, sequences on which tear was visualized, signal intensity of tear on T2-weighted imaging, and presence of low-signal-intensity strands bridging the tear on T2-weighted imaging. Multivariate logistic regression models were used to determine whether MRI characteristics could be used to distinguish between healed and unhealed tears at surgery. RESULTS:Tear location was the most significant characteristic (p<0.001) for distinguishing between healed and unhealed tears: 17 of 18 (94.4%) tears located at the meniscocapsular junction of the medial meniscus were healed and 15 of 68 (22.1%) tears not located at the meniscocapsular junction were healed. For tears not located at the meniscocapsular junction, MRI characteristics significantly associated with healed tears included a tear width of less than 2 mm (p=0.01), tear visualized only on intermediate-weighted imaging (p=0.01), tear showing intermediate or bright signal intensity on T2-weighted imaging (p=0.06), and low-signal-intensity strands bridging the tear on T2-weighted imaging (p<0.001). CONCLUSION/CONCLUSIONS:Most peripheral vertical tears at the meniscocapsular junction of the medial meniscus spontaneously heal. The MRI characteristics of tears not located at the meniscocapsular junction can help distinguish between healed and unhealed tears.