Compressed Sensing SEMAC MRI of Hip, Knee, and Ankle Arthroplasty Implants: A 1.5-T and 3-T Intrapatient Performance Comparison for Diagnosing Periprosthetic Abnormalities.

BACKGROUND. The utility of 3-T MRI for diagnosing joint disorders is established, but its performance for diagnosing abnormalities around arthroplasty implants is unclear. OBJECTIVE. The purpose of this study was to compare 1.5-T and 3-T compressed sensing slice encoding for metal artifact correction (SEMAC) MRI for diagnosing peri-prosthetic abnormalities around hip, knee, and ankle arthroplasty implants. METHODS. Forty-five participants (26 women, 19 men; mean age ± SD, 71 ± 14 years) with symptomatic lower extremity arthroplasty (hip, knee, and ankle, 15 each) prospectively underwent consecutive 1.5- and 3-T MRI examinations with intermediate-weighted (IW) and STIR compressed sensing SEMAC sequences. Using a Likert scale, three radiologists evaluated the presence or absence of periprosthetic abnormalities, including bone marrow edema-like signal, osteolysis, stress reaction/fracture, synovitis, and tendon abnormalities and collections; image quality; and visibility of anatomic structures. Statistical analysis included nonparametric comparison and interchangeability testing. RESULTS. For diagnosing periprosthetic abnormalities, 1.5-T and 3-T compressed sensing SEMAC MRI were interchangeable. Across all three joints, 3-T MRI had lower noise than 1.5-T MRI (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [range, 2-5 and 3-5] vs 3 and 3 [range, 2-5 and 2-4]; p < .01 for both), sharper edges (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [both ranges, 2-5] vs 3 and 3 [range, 2-4 and 2-5]; p < .02 and p < .05), and more effective metal artifact reduction (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [range, 3-5 and 2-5] vs 4 and 4 [both ranges, 3-5]; p < .02 and p = .72). Agreement was moderate to substantial for image contrast (IW and STIR, 0.66 and 0.54 [95% CI, 0.41-0.91 and 0.29-0.80]; p = .58 and p = .16) and joint capsule visualization (IW and STIR, 0.57 and 0.70 [range, 0.32-0.81 and 0.51-0.89]; p = .16 and p = .19). The bone-implant interface was more visible at 1.5 T (median IW and STIR scores, 4 and 4 [both ranges, 2-5] at 1.5 T vs 3 and 3 [both ranges, 2-5] at 3 T; p = .08 and p = .58), but periprosthetic tissues had superior visibility at 3 T (IW and STIR, 4 and 4 [both ranges, 3-5] at 3 T vs 4 and 4 [ranges, 2-5 and 3-5] at 1.5 T; p = .07 and p = .19). CONCLUSION. Optimized 1.5-T and 3-T compressed sensing SEMAC MRI are interchangeable for diagnosing periprosthetic abnormalities, although metallic artifacts are larger at 3 T. CLINICAL IMPACT. With compressed sensing SEMAC MRI, lower extremity arthroplasty implants can be imaged at 3 T rather than 1.5 T.

Fluid intake is a strong predictor of outdoor team sport pre-season training performance.

Our aim was to characterize fluid intake during outdoor team sport training and use generalized additive models to quantify interactions with the environment and performance. Fluid intake, body mass (BM) and internal/external training load data were recorded for male rugby union (n = 19) and soccer (n = 19) athletes before/after field training sessions throughout an 11-week preseason (357 observations). Running performance (GPS) and environmental conditions were recorded each session and generalized additive models were applied in the analysis of data. Mean body mass loss throughout all training sessions was -1.11 ± 0.63 kg (~1.3%) compared with a mean fluid intake at each session of 958 ± 476 mL during the experimental period. For sessions >110 min, when fluid intake reached ~10-19 mL·kg-1 BM the total distance increased (7.47 to 8.06 km, 7.6%; P = 0.049). Fluid intake above ~10 mL·kg-1 BM was associated with a 4.1% increase in high-speed running distance (P < 0.0001). Most outdoor team sport athletes fail to match fluid loss during training, and fluid intake is a strong predictor of running performance. Improved hydration practices during training should be beneficial and we provide a practical ingestion range to promote improved exercise capacity in outdoor team sport training sessions.

Five-Minute Five-Sequence Knee MRI Using Combined Simultaneous Multislice and Parallel Imaging Acceleration: Comparison with 10-Minute Parallel Imaging Knee MRI.

Background Rapid knee MRI using combined simultaneous multislice (SMS) technique and parallel imaging (PI) acceleration can add value through reduced acquisition time but requires validation of clinical efficacy. Purpose To evaluate the performance of clinical fourfold SMS-PI-accelerated, 5-minute, five-sequence, multicontrast knee MRI protocols compared with standard twofold PI-accelerated, 10-minute knee MRI protocols. Materials and Methods Adults with painful knee conditions were prospectively enrolled from April 2018 to October 2019. Participants underwent fourfold SMS-PI-accelerated, 5-minute, turbo spin-echo (TSE) knee MRI and standard-of-care twofold PI-accelerated, 10-minute, TSE knee MRI at either 1.5 T or 3.0 T. Three radiologists independently evaluated the knee MRI studies for meniscal, tendinous, ligamentous, and osseocartilaginous injuries. Statistical analyses included k-based intermethod agreements and diagnostic performance testing. P < .05 was considered indicative of a statistically significant difference. Results A total of 252 adults were evaluated (mean age ± standard deviation, 47 years ± 17; 134 men). Among the participants, 104 (mean age, 42 years ± 18; 57 women) were in the 1.5-T arm and 148 (mean age, 46 years ± 17; 87 men) were in the 3.0-T arm. Twenty-nine participants (mean age, 38 years ± 12; 15 men) in the 1.5-T arm and 42 (mean age, 41 years ± 16; 24 men) in the 3.0-T arm underwent arthroscopy a mean of 45 days ± 31 and 45 days ± 22 after MRI, respectively. Intermethod agreements were good at 1.5 T (κ >0.71 [95% CI: 0.56, 0.83]) and very good at 3.0 T (κ >0.85 [95% CI: 0.69, 0.96]). The diagnostic performances of corresponding 5-minute and 10-minute MRI protocols were similar for 1.5 T, with areas under the receiver operating characteristic curve (AUCs) greater than 0.78 (95% CI: 0.71, 0.84) (P > .32), and 3.0 T, with AUCs greater than 0.83 (95% CI: 0.78, 0.88) (P > .32). Conclusion Comparisons of 5-minute five-sequence simultaneous multislice- and parallel imaging (PI)-accelerated and 10-minute five-sequence PI-accelerated turbo spin-echo MRI of the knee suggest similar performances at 1.5 and 3.0 T. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Subhas in this issue.

10-Min 3D Turbo Spin Echo MRI of the Knee in Children: Arthroscopy-Validated Accuracy for the Diagnosis of Internal Derangement.

BACKGROUND: Ten-minute MRI of the pediatric knee can add value through increased cost-effectiveness and decreased sedation needs but requires validation of its clinical efficacy. PURPOSE: To determine the arthroscopy-based diagnostic accuracy and interreader reliability of 10-min 3D Controlled Aliasing In Parallel Imaging Results In Higher Acceleration (CAIPIRINHA) turbo spin echo (TSE) MRI with two isotropic pulse sequences for the diagnosis of internal derangement in children with painful knee conditions. STUDY TYPE: Prospective. SUBJECTS: Sixty children. FIELD STRENGTH/SEQUENCE: 3T, gradient echo-based scout with automatic anatomical landmark recognition and plane prescription, 3D CAIPIRINHA SPACE TSE. ASSESSMENT: Three fellowship-trained musculoskeletal radiologists evaluated the MRI studies independently and resolved discrepancies through consensus. Outcome variables included image quality, motion artifacts, meniscal abnormalities, anterior and posterior cruciate ligament tears, and cartilage lesions. Arthroscopic surgery served as the standard of reference, which was performed after 37 (range, 1-143) days post-MRI. STATISTICAL TESTS: Diagnostic accuracy analysis of MRI with arthroscopic surgery as the standard of reference. Reliability analysis through calculation of interreader agreements with kappa statistics. RESULTS: All studies were suitable for diagnostic interpretation with good-to-very-good image quality ratings and little-to-no motion degradation ratings in the majority of cases. The sensitivities/specificities/accuracies of 3D CAIPIRINHA TSE MRI were 0.93/0.96/0.94 for 15/60 (25%) medial meniscal tears, 0.95/0.92/0.94 for 21/60 (35%) lateral meniscal tears, 0.83/1.00/0.92 for 6/60 (17%) discoid menisci, 1.00/0.98/0.99 for 16/60 (27%) anterior cruciate ligament tears, 1.0/1.0/1.0 for 2/60 (3%) posterior cruciate ligament tears, 1.00/1.00/1.00 for 5/60 (8%) osteochondritis dissecans lesions, 0.71/0.96/0.84 for 48 (13%) defects in 360 cartilage segments, and 0.85/0.97/0.91 overall. The interreader agreements were overall good-to-very-good (kappa, 0.72-1.00). DATA CONCLUSION: The clinical use of 10-min 3D CAIPIRINHA TSE MRI of the knee in children with painful knee conditions yields an overall high arthroscopy-validated diagnostic accuracy of 91% and good-to-very good interreader reliability for the diagnosis of internal knee derangements. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019;49:e139-e151.

CAIPIRINHA-accelerated 10-min 3D TSE MRI of the ankle for the diagnosis of painful ankle conditions: Performance evaluation in 70 patients.

OBJECTIVES: To test the hypothesis that MRI of the ankle with a 10-min 3D CAIPIRINHA SPACE TSE protocol is at least equivalent for the detection of painful conditions when compared to a 20-min 2D TSE standard of reference protocol. METHODS: Following institutional review board approval and informed consent, 70 symptomatic subjects underwent 3T MRI of the ankle. Six axial, sagittal and coronal intermediate-weighted (IW) and fat-saturated T2-weighted (T2FS) 2D TSE (total acquisition time, 20 min), and two sagittal isotropic IW and T2FS 3D CAIPIRINHA TSE (10 min) pulse sequence prototypes were obtained. Following randomization and anonymization, two musculoskeletal radiologists evaluated the 2D and 3D datasets independently. Descriptive statistics, inter-reader reliability, inter-method concordance, diagnostic definitiveness tests were applied. P-values < 0.05 were considered significant. RESULTS: Raters diagnosed 116 cartilage defects with 2D and 109 with 3D MRI, 35 ligament tears with 2D and 65 with 3D MRI, 18 tendon tears with 2D and 20 with 3D MRI, and 137 osseous abnormalities with 2D and 149 with 3D MRI. The inter-reader agreement was high for 2D (Kendall W, 0.925) and 3D MRI (W, 0.936) (p < 0.05), as was the inter-method concordance (W, 0.919). The diagnostic definitiveness of readers was higher for 3D MRI than 2D MRI in 10-27% of the time, while the reverse was true in 7-11% of the time (p < 0.01). CONCLUSIONS: The performance of 10-min 3D CAIPIRINHA SPACE MRI for the detection of painful ankle conditions is similar to that of a 20-min 2D TSE MRI reference standard. KEY POINTS: • CAIPIRINHA Acceleration facilitates isotropic 3D MRI of the Ankle in 10 min. • 10-min 3D CAIPIRINHA MRI and 20-min 2D TSE MRI have similar performance. • 3D CAIPIRINHA SPACE MRI afforded higher diagnostic definitiveness of readers.

Metal artifact reduction MRI for total ankle replacement sagittal balance evaluation.

BACKGROUND: Restoration of anatomical relationship between talus and tibia is crucial for longevity of total ankle replacement (TAR). Weight-bearing (WB) radiographs are the standard for evaluating the sagittal balance alignment, but are prone to rotational misalignment and altered measurements. Metal artifact reduction sequence (MARS) MRI allows visualization of periprosthetic landmarks and alignment of the image plane to the true sagittal axis of the implant. The purpose of this study was to compare TAR sagittal balance measurements on MARS MRI and WB radiographs. METHODS: Twenty-three subjects with TAR [10 men/13 women, age 60 (41-73) years; 13 (3-24) months post-op] underwent MARS MRI and standard lateral WB radiographs. Standardized MARS MR images were aligned to the sagittal talar component axis. Three observers performed sagittal balance alignment measurements twice in an independent, random and blinded fashion. Lateral Talar Station (LTS), tibial axis-to-talus (T-T) ratio and normalized tibial axis-to-lateral-process (T-L) distance were measured. Concordance correlation coefficients (CCC) and intraclass correlation coefficients (ICC) were used for statistical analysis. In addition, mixed effects linear models were employed to assess overall concordance of the two image types. RESULTS: The intraobserver agreement was excellent for radiographic (CCC=0.96) and MRI (CCC=0.90-0.97) measurements. Interobserver agreements were good-to-excellent with overall slightly higher agreements for MRI (ICC=0.78-0.94) than radiography (ICC=0.78-0.90) measurements. The T-T ratios of radiographs and MRI showed a high degree of concordance, whereas LTS was significantly lower on MRI when compared with radiographs, and T-L distance showed notable disagreement between the two imaging types. CONCLUSION: Sagittal balance measurements performed on standardized weight-bearing radiographs and standardized MARS MRI demonstrate substantial correlation and similarity. Given its high intra and interobserver agreement, MARS MRI may be helpful for the evaluation of TAR sagittal balance. LEVEL OF EVIDENCE: Level II - Prospective Comparative Study.

Synthetic MRI of the Knee: Phantom Validation and Comparison with Conventional MRI.

Purpose To test the hypothesis that synthetic MRI of the knee generates accurate and repeatable quantitative maps and produces morphologic MR images with similar quality and detection rates of structural abnormalities than does conventional MRI. Materials and Methods Data were collected prospectively between January 2017 and April 2018 and were retrospectively analyzed. An International Society for Magnetic Resonance in Medicine-National Institute of Standards and Technology phantom was used to determine the accuracy of T1, T2, and proton density (PD) quantification. Statistical models were applied for correction. Fifty-four participants (24 men, 30 women; mean age, 40 years; range, 18-62 years) underwent synthetic and conventional 3-T MRI twice on the same day. Fifteen of 54 participants (28%) repeated the protocol within 9 days. The intra- and interday agreements of quantitative cartilage measurements were assessed. Contrast-to-noise (CNR) ratios, image quality, and structural abnormalities were assessed on corresponding synthetic and conventional images. Statistical analyses included the Wilcoxon test, χ2 test, and Cohen Kappa. P values less than or equal to .01 were considered to indicate a statistically significant difference. Results Synthetic MRI quantification of T1, T2, and PD values had an overall model-corrected error margin of 0.8%. The synthetic MRI interday repeatability of articular cartilage quantification had native and model-corrected error margins of 3.3% and 3.5%, respectively. The cartilage-to-fluid CNR and menisci-to-fluid CNR was higher on synthetic than conventional MR images (P ≤ .001, respectively). Synthetic MRI improved short-tau inversion recovery fat suppression (P ˂ .01). Intermethod agreements of structural abnormalities were good (kappa, 0.621-0.739). Conclusion Synthetic MRI of the knee is accurate for T1, T2, and proton density quantification, and simultaneously generated morphologic MR images have detection rates of structural abnormalities similar to those of conventional MR images, with similar acquisition time. © RSNA, 2018.

Metal artifact reduction MRI of total ankle arthroplasty implants.

OBJECTIVES: To assess high-bandwidth and compressed sensing-(CS)-SEMAC turbo spin echo (TSE) techniques for metal artifact reduction MRI of total ankle arthroplasty (TAA) implants. METHODS: Following institutional approval and consent, 40 subjects with TAA implants underwent 1.5-T MRI prospectively. Evaluations included bone-implant interfaces, anatomical structures, abnormal findings and differential diagnoses before and after MRI. AUCs of P-P plots were used to determine superiority. Statistical differences were evaluated with McNemar and chi-square tests. P-values ≤ 0.05 were considered significant. RESULTS: CS-SEMAC TSE was superior to high-bandwidth TSE in showing the bone-implant interfaces (AUC=0.917), periprosthetic bone, tendons and joint capsule (AUC=0.337-0.766), bone marrow oedema (43 % difference, p=0.041), interface osteolysis (63 %, p=0.015), tendinopathy (62 %, p=0.062), periprosthetic fractures (60 %, p=0.250), synovitis (43 %, p=0.250), as well as reader confidence for bone marrow oedema (p=<0.001), fracture (p=0.001), interface osteolysis (p=0.003), synovitis (p=0.027) and tendinopathy (p=0.034). The number of differential diagnoses in symptomatic subjects after the MRI with CS-SEMAC decreased from 3 (1-4) to 1 (1-2) (p<0.001). CONCLUSIONS: MRI of TAA implants with CS-SEMAC improves the diagnosis of interface osteolysis, periprosthetic bone marrow oedema, fractures and tendinopathy when compared to high-BW TSE, and has a positive effect on patient management. KEY POINTS: • High-bandwidth TSE and compressed sensing SEMAC improve MRI of ankle arthroplasty implants. • Compressed sensing SEMAC improves bone-implant interfaces, periprosthetic bone, tendons and joint capsule visibility. • Compressed sensing SEMAC improves the diagnosis of osteolysis, tendinopathy, fractures and synovitis. • MRI decreases the number of clinical differential diagnoses of painful ankle arthroplasty implants.

High-resolution metal artifact reduction MR imaging of the lumbosacral plexus in patients with metallic implants.

OBJECTIVE: To assess the quality and accuracy of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) for the diagnosis of lumbosacral neuropathies in patients with metallic implants in the pelvis. MATERIALS AND METHODS: Twenty-two subjects with lumbosacral neuropathy following pelvic instrumentation underwent 1.5-T MARS MRI including optimized axial intermediate-weighted and STIR turbo spin echo sequences extending from L5 to the ischial tuberosity. Two readers graded the visibility of the lumbosacral trunk, sciatic, femoral, lateral femoral cutaneous, and obturator nerves and the nerve signal intensity of nerve, architecture, caliber, course, continuity, and skeletal muscle denervation. Clinical examination and electrodiagnostic studies were used as the standard of reference. Descriptive, agreement, and diagnostic performance statistics were applied. RESULTS: Lumbosacral plexus visibility on MARS MRI was good (4) or very good (3) in 92% of cases with 81% exact agreement and a Kendall's W coefficient of 0.811. The obturator nerve at the obturator foramen and the sciatic nerve posterior to the acetabulum had the lowest visibility, with good or very good ratings in only 61% and 77% of cases respectively. The reader agreement for nerve abnormalities on MARS MRI was excellent, ranging from 95.5 to 100%. MARS MRI achieved a sensitivity of 86%, specificity of 67%, positive predictive value of 95%, and negative predictive value of 40%, and accuracy of 83% for the detection of neuropathy. CONCLUSION: MARS MRI yields high image quality and diagnostic accuracy for the assessment of lumbosacral neuropathies in patients with metallic implants of the pelvis and hips.

Diagnostic Performance of Advanced Metal Artifact Reduction MRI for Periprosthetic Shoulder Infection.

BACKGROUND: The diagnosis of periprosthetic shoulder infection (PSI) in patients with a painful arthroplasty is challenging. Magnetic resonance imaging (MRI) may be helpful, but shoulder implant-induced metal artifacts degrade conventional MRI. Advanced metal artifact reduction (MARS) improves the visibility of periprosthetic bone and soft tissues. The purpose of our study was to determine the reliability, repeatability, and diagnostic performance of advanced MARS-MRI findings for diagnosing PSI. METHODS: Between January 2015 and December 2019, we enrolled consecutive patients suspected of having PSI at our academic hospital. All 89 participants had at least 1-year clinical follow-up and underwent standardized clinical, radiographic, and laboratory evaluations and advanced MARS-MRI. Two fellowship-trained musculoskeletal radiologists retrospectively evaluated the advanced MARS-MRI studies for findings associated with PSI in a blinded and independent fashion. Both readers repeated their evaluations after a 2-month interval. Interreader reliability and intrareader repeatability were assessed with κ coefficients. The diagnostic performance of advanced MARS-MRI for PSI was quantified using sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). When applying the International Consensus Meeting (ICM) 2018 criteria, of the 89 participants, 22 (25%) were deemed as being infected and 67 (75%) were classified as being not infected (unlikely to have PSA and not requiring a surgical procedure during 1-year follow-up). RESULTS: The interreader reliability and intrareader repeatability of advanced MARS-MRI findings, including lymphadenopathy, joint effusion, synovitis, extra-articular fluid collection, a sinus tract, rotator cuff muscle edema, and periprosthetic bone resorption, were good (κ = 0.61 to 0.80) to excellent (κ > 0.80). Lymphadenopathy, complex joint effusion, and edematous synovitis had sensitivities of >85%, specificities of >90%, odds ratios of >3.6, and AUC values of >0.90 for diagnosing PSI. The presence of all 3 findings together yielded a PSI probability of >99%, per logistic regression analysis. CONCLUSIONS: Our study shows the clinical utility of advanced MARS-MRI for diagnosing PSI when using the ICM 2018 criteria as the reference standard. Although the reliability and diagnostic accuracy were high, these conclusions are based on our specific advanced MARS-MRI protocol interpreted by experienced musculoskeletal radiologists. Investigations with larger sample sizes are needed to confirm these results. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Effect of Individual Environmental Heat-Stress Variables on Training and Recovery in Professional Team Sport.

CONTEXT: Exercise in hot environments increases body temperature and thermoregulatory strain. However, little is known regarding the magnitude of effect that ambient temperature (Ta), relative humidity (RH), and solar radiation individually have on team-sport athletes. PURPOSE: To determine the effect of these individual heat-stress variables on team-sport training performance and recovery. METHODS: Professional Australian Rules Football players (N = 45) undertook 8-wk preseason training producing a total of 579 outdoor field-based observations with Ta, RH, and solar radiation recorded at every training session. External load (distance covered, in m/min; percentage high-speed running [%HSR] >14.4 km/h) was collected via a global positioning system. Internal load (ratings of perceived exertion and heart rate) and recovery (subjective ratings of well-being and heart-rate variability [root mean square of the successive differences]) were monitored throughout the training period. Mixed-effects linear models analyzed relationships between variables using standardized regression coefficients. RESULTS: Increased solar-radiation exposure was associated with reduced distance covered (-19.7 m/min, P < .001), %HSR (-10%, P < .001) during training and rMSSD 48 h posttraining (-16.9 ms, P = .019). Greater RH was associated with decreased %HSR (-3.4%, P = .010) but increased percentage duration >85% HRmax (3.9%, P < .001), ratings of perceived exertion (1.8 AU, P < .001), and self-reported stress 24 h posttraining (-0.11 AU, P = .002). In contrast, higher Ta was associated with increased distance covered (19.7 m/min, P < .001) and %HSR (3.5%, P = .005). CONCLUSIONS: The authors show the importance of considering the individual factors contributing to thermal load in isolation for team-sport athletes and that solar radiation and RH reduce work capacity during team-sport training and have the potential to slow recovery between sessions.

Fully Automated 10-Minute 3D CAIPIRINHA SPACE TSE MRI of the Knee in Adults: A Multicenter, Multireader, Multifield-Strength Validation Study.

OBJECTIVES: The aim of this study was to test the hypothesis that magnetic resonance imaging (MRI) of the knee with 10-minute 3-dimensional (3D) controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) sampling perfection with application optimized contrast using different flip angle evolutions (SPACE) turbo spin echo (TSE) protocols can replace 20-minute 2-dimensional (2D) TSE standard-of-reference protocols for the diagnosis of internal derangement. MATERIALS AND METHODS: After internal review board approval and prospective informed consent, 100 symptomatic subjects underwent MRI of the knee at 3 T and 50 symptomatic subjects at 1.5 T, consisting of 10-minute 3D CAIPIRINHA SPACE TSE and 20-minute standard-of-reference 2D TSE protocols. Two fellowship-trained musculoskeletal radiologists assessed the studies in an anonymized and randomized fashion for structural abnormalities. Descriptive statistics, interreader reliability, intermethod concordance, diagnostic definitiveness, and interchangeability tests were applied. P values equal to or smaller than 0.01 were considered significant. RESULTS: The interchangeability analysis showed that the 3D MRI can replace the 2D MRI protocols, whereas a superiority of 3D MRI was suggested statistically for the detection of medial and lateral meniscal tears, cartilage defects, and bone marrow edema by significantly higher common pair exact match proportions of readers (P < 0.01, respectively).The overall interreader reliabilities were 89% of exact matches for 2D TSE (κ, 0.842) and 96% of exact matches for 3D TSE (κ, 0.941) (P < 0.01). There was good intermethod concordance (κ, 0.736; range, 0.579-1.000). The interreader reliability (2D TSE: κ, 0.748 [0.603-1.000]; 3D TSE: κ, 0.901 [0.797-1.000]) and diagnostic definitiveness were significantly higher for the 3D than 2D MRI (P < 0.01). CONCLUSIONS: 10-minute 3D CAIPIRINHA SPACE TSE MRI protocols can replace 20-minute 2D TSE standard-of-reference MRI protocols for the evaluation of internal derangement of the knee by producing similar results in individual patient diagnoses, whereas interpretations of 3D CAIPIRINHA SPACE TSE MRI examinations resulted in an overall higher interreader reliability, intermethod concordance, and reader definitiveness.

Distortions in the memory of the pitch of speech.

Corneille, Huart, Becquart, & Brédart (2004) found that people remember ambiguous race faces as closer to a race prototype than they actually are. In three studies, we examined whether this memory bias generalizes to voice memory. In Studies 1 and 2, participants listened to synthesized male and female speech samples (high, moderate, or low pitch) and were asked to identify a voice target when paired against distracters higher or lower in pitch. The results showed that pitch distortions occurred, with the pattern consistent with assimilation toward low and high ends of the pitch continuum. Study 3 replicated this result with a wider voice pitch range. The results parallel those of Corneille et al. (2004). The implications of this work are discussed.

Use of speech generating devices can improve perception of qualifications for skilled, verbal, and interactive jobs.

BACKGROUND: We have previously demonstrated that when speech generating devices (SGD) are used as assistive technologies, they are preferred over the users' natural voices. OBJECTIVE: We sought to examine whether using SGDs would affect listener's perceptions of hirability of people with complex communication needs. METHODS: In a series of three experiments, participants rated videotaped actors, one using SGD and the other using their natural, mildly dysarthric voice, on (a) a measurement of perceptions of speaker credibility, strength, and informedness and (b) measurements of hirability for jobs coded in terms of skill, verbal ability, and interactivity. Experiment 1 examined hirability for jobs varying in terms of skill and verbal ability. Experiment 2 was a replication that examined hirability for jobs varying in terms of interactivity. Experiment 3 examined jobs in terms of skill and specific mode of interaction (face-to-face, telephone, computer-mediated). RESULTS AND CONCLUSIONS: Actors were rated more favorably when using SGD than their own voices. Actors using SGD were also rated more favorably for highly skilled and highly verbal jobs. This preference for SGDs over mildly dysarthric voice was also found for jobs entailing computer-mediated-communication, particularly skillful jobs.

Identification of individuals with insulin resistance using routine clinical measurements.

Insulin resistance is a treatable precursor of diabetes and potentially of cardiovascular disease as well. To identify insulin-resistant patients, we developed decision rules from measurements of obesity, fasting glucose, insulin, lipids, and blood pressure and family history in 2,321 (2,138 nondiabetic) individuals studied with the euglycemic insulin clamp technique at 17 European sites; San Antonio, Texas; and the Pima Indian reservation. The distribution of whole-body glucose disposal appeared to be bimodal, with an optimal insulin resistance cutoff of <28 micromol/min . kg lean body mass. Using recursive partitioning, we developed three types of classification tree models: the first, based on clinical measurements and all available laboratory determinations, had an area under the receiver operator characteristic curve (aROC) of 90.0% and generated a simple decision rule: diagnose insulin resistance if any of the following conditions are met: BMI >28.9 kg/m(2), homeostasis model assessment of insulin resistance (HOMA-IR) >4.65, or BMI >27.5 kg/m(2) and HOMA-IR >3.60. The fasting serum insulin concentrations corresponding to these HOMA-IR cut points were 20.7 and 16.3 microU/ml, respectively. This rule had a sensitivity and specificity of 84.9 and 78.7%, respectively. The second model, which included clinical measurements but no laboratory determinations, had an aROC of 85.0% and generated a decision rule that had a sensitivity and specificity of 78.7 and 79.6%, respectively. The third model, which included clinical measurements and lipid measurements but not insulin (and thus excluded HOMA-IR as well), had a similar aROC (85.1%), sensitivity (81.3%), and specificity (76.3%). Thus, insulin-resistant individuals can be identified using simple decision rules that can be tailored to specific needs.

The Role of ADC-Based Thermometry in Measuring Brain Intraventricular Temperature in Children.

BACKGROUND AND PURPOSE: To determine the feasibility of apparent diffusion coefficient (ADC)-based thermometry to assess intraventricular temperature in children. METHODS: ADC maps were generated from diffusion tensor imaging data, which were acquired with diffusion gradients along 20 noncollinear directions using a b-value of 1000 s/mm(2) . The intraventricular temperature was calculated based on intraventricular ADC values and the mode method as previously reported. The calculated intraventricular temperature was validated with an estimated brain temperature based on temporal artery temperature measurements. We included 120 children in this study (49 females, 71 males, mean age 6.63 years), 15 consecutive children for each of the following age groups: 0-1, 1-2, 2-4, 4-6, 6-8, 8-10, 10-14, and 14-18 years. Forty-three children had a normal brain MRI and 77 children had an abnormal brain scan. Polynomial fitting to the temperature distribution and subsequent calculation of mode values was performed. A correlation coefficient and a coefficient of determination were calculated between ADC calculated temperatures and estimated brain temperatures. Linear regression analysis was performed to investigate the two temperature measures. RESULTS: ADC-based intraventricular temperatures ranged between 31.5 and 39.6 °C, although estimated brain temperatures ranged between 36.3 and 38.1 °C. The difference between the temperatures is larger for children with more than 8,000 voxels within the lateral ventricles compared to children with less than 8,000 voxels. The correlation coefficient between ADC-based temperatures and the estimated brain temperatures is .1, the respective R(2) is .01 indicating that 1% of the changes in estimated brain temperatures are attributable to corresponding changes in ADC-based temperature measurements (P = .275). CONCLUSIONS: ADC-based thermometry has limited application in the pediatric population mainly due to a small ventricular size.

Acute Brain Imaging in Children: Can MRI Replace CT as a Screening Tool?

BACKGROUND AND PURPOSE: To determine if axial T2-weighted imaging can serve as screening tool for pediatric brain imaging. METHODS: We retrospectively evaluated consecutive brain magnetic resonance imaging (MRI) data of 161 children (74 girls) with a mean age of 7.44 ± 5.71 years. Standard of reference was the final report of neuroradiology attendings. Three readers with different levels of experience were blinded for clinical diagnoses and study indications. First, readers studied only the axial T2-weighted screening sequence. Second, they studied all available anatomical and functional MRI sequences as performed per standard protocol for each clinical indication. The readings were classified as normal or abnormal. Sensitivity and specificity were measured. RESULTS: Axial T2 screening yielded a sensitivity of 77-88% and a specificity of 92%. The full studies/data sets had a sensitivity of 89-95% and a specificity of 86-93%. Nineteen of 167 studies were acquired for acute and 148 of 167 studies for nonacute clinical indication. Twenty-five false-negative diagnoses paneled in three groups were made by all readers together. Readers misread four of 19 studies with acute and 21 of 148 studies with nonacute clinical indication. Four of 21 misread studies with nonacute indications harbored unexpected findings needing management. CONCLUSIONS: Axial T2 screening can detect pediatric brain abnormalities with high sensitivity and specificity and can possibly replace CT as screening tool if the reading physician is aware of possible limitations/pitfalls. The level of experience influences sensitivity and specificity. Adding diffusion-weighted imaging and susceptibility-weighted imaging to a 3-dimensional T2-weighted sequence would most likely further increase sensitivity and specificity.

Effects of perceived disability on persuasiveness of computer-synthesized speech.

Are perceptions of computer-synthesized speech altered by the belief that the person using this technology is disabled? In a 2 x 2 factorial design, participants completed an attitude pretest and were randomly assigned to watch an actor deliver a persuasive appeal under 1 of the following 4 conditions: disabled or nondisabled using normal speech and disabled or nondisabled using computer-synthesized speech. Participants then completed a posttest survey and a series of questionnaires assessing perceptions of voice, speaker, and message. Natural speech was perceived more favorably and was more persuasive than computer-synthesized speech. When the speaker was perceived to be speech-disabled, however, this difference diminished. This finding suggests that negatively viewed assistive technologies will be perceived more favorably when used by people with disabilities.

Sex differences in persuadability of human and computer-synthesized speech: meta-analysis of seven studies.

To examine sex differences in persuasiveness, we conducted a meta-analysis of seven studies from our laboratory on reactions to human versus computer-synthesized speech. We tested three hypotheses: (1) people would be more persuaded by human speech than by computer-synthesized speech, (2) women would be slightly more persuaded than men, and (3) the sex difference would be more pronounced for human speech than for synthetic speech. While there was support for the first two hypotheses, there was none for the third. Also, no consistent support was found for a moderating effect of mode of presentation, audio versus video.

Listeners' preference for computer-synthesized speech over natural speech of people with disabilities.

PURPOSE/OBJECTIVE: There are few controlled experimental studies that examine reactions to people with speech disabilities. We conducted 2 studies designed to examine participants' reactions to persuasive appeals delivered by people with physical disabilities and mild to moderate dysarthria. RESEARCH METHOD/DESIGN: Research participants watched video clips delivered by actors with bona fide disabilities and subsequently rated the argument, message, and the speaker. The first study (n = 165) employed a between-groups design that examined reactions to natural dysarthric speech, synthetic speech as entered into a keyboard by hand, and synthetic speech as entered into a keyboard with a headwand. The second study (n = 27) employed a within-groups design that examined how participants reacted to natural dysarthric speech versus synthetic speech as entered into a keyboard by hand. RESULTS: Both of these studies provide evidence that people rated the argument, message, and speaker more favorably when people with disabilities used synthetic speech than when they spoke in their natural voice. CONCLUSIONS/IMPLICATIONS: The implications are that although people react negatively to computer-synthesized speech, they prefer it to and find it more persuasive than the speech of people with disabilities. This appears to be the case even if the speech is only moderately impaired and is as intelligible as the synthetic speech. Hence, the decision to use synthetic speech versus natural speech can be further complicated by an understanding that even the intelligible speech of people with disabilities leads to more negative reactions than synthetic speech.