Metastatic Diffusion Volume Based on Apparent Diffusion Coefficient as a Prognostic Factor in Castration-Resistant Prostate Cancer.

BACKGROUND: Whole-body diffusion-weighted MRI (WB-DWI) is useful for assessing disease activity in castration-resistant prostate cancer (CRPC). MET-RADS-P is a subjective assessment-based reporting system proposed to standardize the interpretation of WB-DWI. However, a quantitative evaluation of WB-DWI has not been fully investigated. PURPOSE: To investigate the validity, and analyze the prognostic value, of quantitative evaluation of WB-DWI based on apparent diffusion coefficient (ADC) values for CRPC. STUDY TYPE: Retrospective. POPULATION: Sixty-six patients with CRPC. The median age was 75 years. During the median follow-up period of 25.2 months, 23 of 66 patients (34.8%) died of prostate cancer. FIELD STRENGTH/SEQUENCE: A 1.5 T WB-DWI was used with two b-values (0 s/mm2 -1000 s/mm2 ). A single-shot echo-planar imaging sequence was used. ASSESSMENT: WB-DWI were evaluated by three readers according to MET-RADS-P scoring system. Using imaging software, Attractive BDScore, tumor diffusion volume (mDV) and ADC value of metastatic lesion (mADC) was calculated by two readers. The mDV was calculated with ADC values (×10-3  mm2 /sec) of 0.4-0.9 (mDV0.4-0.9 ), 0.9-1.4 (mDV0.9-1.4 ), and 1.4-1.8 (mDV1.4-1.8 ), respectively. STATISTICAL TESTS: Spearman's rank correlation coefficient was used to assess the correlation. The relationships between the variables with cancer-specific survival (CSS) were evaluated. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: mDVs showed a strong positive correlation with MET-RADS-P scores (r = 0.90/0.87, P < 0.05 for both). mDV showed a statistically significant association with CSS (hazard ratio [HR]: 1.01, P < 0.05). When the mDVs calculated based on the ADC values were included, mDV0.4-0.9 (HR: 1.02, P < 0.05) and the number of therapeutic lines (HR: 1.35, P < 0.05) were significant independent indicators of CSS shortening. CONCLUSION: Assessment of metastatic tumor volume based on ADC values can be used in the prognostic evaluation of patients with CRPC. WB-DWI might be a potential prognostic imaging biomarker for CRPC. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.

Possible predictive formulas for quantitative and time-based estimation of muscle strength during motion.

[Purpose] To examine the validity of the predictive formulas based on the angle information of the segment center of mass and moments of inertia, and to propose a joint moment estimation method. [Participants and Methods] Twenty nine young healthy adults were divided into two groups: the Creation group (20 adults) was needed to create the prediction formulas, and the Verification group (9 adults) was needed to verify the formulas. By monitoring the Creation group, the angular information from inertial motion sensors and moments of inertia of each limb were used to estimate actual ankle joint moment and knee joint moment. Thereafter, the actual joint moments was derived from the Verification group and compared to the predicted values via Pearson correlations. [Results] Good to excellent correlations were obtained between the actual joint moments of the two groups for most of the motions. [Conclusion] It is suggested that the predictive formulas created from the angle information of the segment center of mass and moments of inertia can be used for an approximate estimation of the lower limb joint moments in the sagittal plane and more clinically useful tools need to be considered in the future.

Diversity and regularity in infant crawling with typical development.

[Purpose] The purpose of this longitudinal study was to investigate the diversity in infant crawling and examine the quantitative regularity in crawling variations necessary for the acquisition of walking in infants with typical development. [Participants and Methods] Infants with no neurological or orthopedic problems participated in this study. Using Internet Protocol (IP) cameras, crawling was simultaneously filmed from six different angles. Filming was continued until the acquisition of independent walking. The crawling movement in the video was coded. We considered the number of different completed codes as the number of variations and examined the cumulative number during the filming period in each participant. [Results] Nineteen infants completed the study. The pattern of change in the cumulative number of variations with increasing age (in days) varied between cases. Although the cumulative number of crawling variations at the time of acquisition of independent walking was inconsistent, it was negatively correlated with the crawling start age (in days). [Conclusion] Diversity exists in infant crawling. Infants who start crawling at a younger age tend to express more variation, whereas infants who start crawling when older tend to express less variation.

The interrelationship between lower limb movement, muscle activity, and joint moment during half squat and gait.

Joint moment is the resultant force of limb movements. However, estimation methods for joint moments using surface electromyography frequently use joint angles instead of limb angles. The limb angle in joint moment estimation using electromyography could clarify the effects of muscle activity on the limbs: acceleration, deceleration, or stabilization. No study has quantified the comprehensive relationship between limb movement, muscle activity, and joint moment. This study aimed to determine the influencing factors for ankle-joint moment and knee-joint moment in the sagittal plane among muscle activities and parameters related to limb movements during half squat and gait. This study included 29 healthy adults (16 female participants, 21.1 ± 2.09 years). Using inertial measurement units, thigh, shank, and foot inclination angles and angular accelerations were calculated as the parameters of limb movements. Muscle activations of the biceps femoris long head, rectus femoris, gastrocnemius, and tibialis anterior were measured. Ankle joint moment and knee-joint moment were measured using a three-dimensional motion capture system and two force plates. Regression models showed high accuracy in measuring ankle-joint moment during a half squat and gait (R2f = 0.92, 0.97, respectively) and knee-joint moment during a half squat (R2f = 0.98), but not knee-joint moment during gait (R2f = 0.63). However, only a maximum of five parameters were selected from muscle activities and limb angular information. Tibialis anterior and gastrocnemius activity were the largest contributors to ankle-joint moment during a half squat and gait, respectively, while muscle activities were not directly reflected in the knee-joint moment during either movement. Consideration of the interrelationships among limb movement, muscle activity, and joint moment is required when adjusting joint movements according to the target and aim of the therapeutic interventions.