Effectiveness of a Tailored Anterior Saturation Band in the Improvement of the Image Quality of Pelvic Magnetic Resonance for Assessing Rectal Cancer.

PURPOSE: We sought to test the effectiveness of the application of a tailored anterior saturation band (ASB) to improve the image quality of pelvic magnetic resonance imaging (MRI) for assessing rectal cancer. METHODS: A total of 165 patients with MRI assessment of rectal cancer between 2013 and 2015 were included. The image quality scores (4-point scale: 1, nondiagnostic through 4, excellent) of MRI without and with tailored ASBs were compared. Sensitivity, specificity, positive and negative predictive values, and accuracy of pelvic MRIs with and without a tailored ASB for T-staging in 65 patients with direct surgery and 67 patients with chemoradiotherapy before surgery were evaluated. RESULTS: Two independent raters exhibited moderate-to-excellent interobserver agreements (κ = 0.529-0.879) in the grading of MRI image quality. Overall, the quality scores of sagittal and axial T2-weighted images with tailored ASBs were significantly improved compared with MRIs without ASBs (3.5 ± 0.3 vs. 2.7 ± 0.8 [mean ± SD]; P < .001, and 3.6 ± 0.3 vs. 2.8 ± 0.8; P < .001, respectively). The application of tailored ASBs in MRIs improved the averaged accuracies for staging of ≤ T2, T3, and T4 tumors from 87.7%, 78.5%, and 90.8% to 93.1%, 86.9%, and 97.7%, respectively. In post-chemoradiotherapy MRI follow-ups, the use of tailored ASBs also improved the average accuracies for staging of yT0, yT1-2, yT3, and yT4 tumors from 80.6%, 73.1%, 73.9%, and 91.0%, to 85.8%, 82.9%, 85.1%, and 94.0%, respectively. CONCLUSIONS: Application of a tailored ASB in pelvic MRI is effective in substantially reducing motion artifacts, significantly upgrading image quality, and improving accuracies of rectal tumor staging.

Noninvasive Shock Wave Treatment for Capsular Contractures After Breast Augmentation: A Rabbit Study.

BACKGROUND: Capsular contracture is the most common complication of breast augmentation. Although numerous procedures are intended to prevent capsular contracture, their efficacy does not satisfy surgeons or patients. In the present study, we used shock waves to develop innovative protocols to treat capsular contracture in rabbits. METHODS: We used shock waves to treat capsular contracture in a rabbit model. Six clinical parameters were evaluated to determine the treatment efficacy of shock waves on the pathological histology of capsular contracture. Dual-flip-angle T1-mapping magnetic resonance imaging was used to confirm the pathological findings. RESULTS: Among the parameters, myxoid change, vascular proliferation, and lymphoplasma cell infiltration around the capsule increased more after treatment than they did in a control group. Capsular thickness, inner thinner collagen layer, and capsule wall collagen deposition decreased after shock wave treatment; only the inner thinner collagen layer and capsule wall collagen deposition changed significantly. The MRI findings for both scar thickness and water content were consistent with pathological biology findings. CONCLUSION: This was the first pilot study and trial to treat capsular contractures using shock waves. We found that shock waves can cause changes in the structure or the composition of capsular contracture. We conclude that the treatment could decrease water content, loosen structure, decrease collagen deposition, and might alleviate scar formation from capsular contracture. We believe that the treatment could be a viable remedy for capsular contractures. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Impact of Flip Angle and TR on the Enhancement Ratio of Dynamic Gadobutrol-enhanced MR Imaging: In Vivo VX2 Tumor Model and Computer Simulation.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely used to diagnose cancer and monitor therapy. The maximum enhancement ratio (ERmax) obtained from the curve of signal intensity over time could be a biomarker to distinguish cancer from normal tissue or benign tumors. We evaluated the impact of flip angle (FA) and repetition time (TR) on the ERmax values of dynamic gadobutrol-enhanced MR imaging, obtaining T1-weighted (T1W) MR imaging of VX2 tumors using 2-dimensional fast spoiled gradient echo (2D FSPGR) with various FAs (30°, 60° and 90°) at 1.5 tesla before and after injection of 0.1 mmol/kg gadobutrol. In vivo study indicated significant differences between ERmax values and area under the ER-time curve (AUC100) of VX2 tumors and muscle tissue, with the highest ERmax and AUC100 at FA 90°. Computer simulation also demonstrated the ER as a strictly increasing monotonic function in the closed interval [0°, 90°] for a given TR when using T1W FSPGR, and the highest ER value always occurred at FA 90°. The FA for the highest ER differed from that for the highest signal-to-noise or contrast-to-noise ratio. For long TR, the ER value increases gradually. However, for short TR, the ER value increases rapidly and plateaus so that the ER value changes little beyond a certain FA value. Therefore, we suggest use of a higher FA, near 90°, to obtain a higher ERmax for long TR in 2D SPGR or FSPGR and a smaller FA, much less than 90°, to reach an appropriate ERmax for short TR in 3D SPGR or FSPGR. This information could be helpful in setting the optimal parameters for DCE-MRI.

Does low-intensity pulsed ultrasound treatment repair articular cartilage injury? A rabbit model study.

BACKGROUND: Low-intensity pulsed ultrasound (LIPUS) regiment has been used to treat fractures with non-union and to promote bone union in general. The effect of LIPUS on articular cartilage metabolism has been characterized. Yet, the effect of LIPUS to repair articular cartilage injury remains unclear in vivo. METHODS: We designed a study to investigate the effect of LIPUS on articular cartilage repairing in a rabbit severe cartilage injury model. Eighteen rabbits were divided into three groups: Sham-operated group, operated group without-LIPUS-treatment, operated group with-LIPUS-treatment (a daily 20-minute treatment for 3 months). Full-thickness cartilage defects were surgically created on the right side distal femoral condyle without intending to penetrate into the subchondral bone, which mimicked severe chondral injury. MR images for experimental joints, morphology grading scale, and histopathological Mankin score were evaluated. RESULTS: The preliminary results showed that the operated groups with-LIPUS-treatment and without-LIPUS-treatment had significantly higher Mankin score and morphological grading scale compared with the sham-operated group. However, there was no significant difference between the with-LIPUS-treatment and without-LIPUS-treatment groups. Cartilage defects filled with proliferative tissue were observed in the with-LIPUS-treatment group grossly and under MR images, however which presented less up-take under Alcian blue stain. Furthermore, no new deposition of type II collagen or proliferation of chondrocyte was observed over the cartilage defect after LIPUS treatment. CONCLUSION: LIPUS has no significant therapeutic potential in treating severe articular cartilage injury in our animal study.

Preliminary study of non-invasive shock wave treatment of capsular contracture after breast implant: animal model.

The incidence rate of capsular contracture after breast implant is about 8% to 12%. Patients would feel extremely uncomfortable after scar formation. Administering oral medications (such as vitamin E and Zafirlukast tablets, etc.) or invasive breast capsulectomy surgery was commonly used for capsular contracture repair in clinical therapy. However, the therapeutic effect is still under investigation. Shock waves can be used to remove soft connective tissue in clinical applications. It has been widely used in orthopedics and rehabilitation. No related research paper about shock wave treatment of capsular contracture has been published yet. It might provide another choice for capsular contracture repair. In order to simulate breast implantation, two silica-gel bags filled with normal saline were implanted into New Zealand rabbit's thighs bilaterally as an animal model. Six weeks later, daily shock wave treatment on the right thigh was performed for six weeks after capsular contractures were formed, while the other thigh was used as a control. Then, magnetic resonance imaging (MRI) was used to compare the difference between treated and un-treated thighs. Afterwards, pathological sections were analyzed to confirm the findings. It has been demonstrated that shock wave treatments are capable of changing the structure and composition of capsular contractures. The structure of scar became myxoid changed or collagen deposition of scar decreased after shock wave treatment, hence, the formation of scars decreased. Increased myxoid and decreased collagen deposition has also been found.

Quantifying liver cirrhosis by extracting significant features from MRI T2 image.

Most patients with liver cirrhosis must undergo a series of clinical examinations, including ultrasound imaging, liver biopsy, and blood tests. However, the quantification of liver cirrhosis by extracting significant features from a T2-weighted magnetic resonance image (MRI) provides useful diagnostic information in clinical tests. Sixty-two subjects were randomly selected to participate in this retrospective analysis with assigned to experimental and control groups. The T2-weighted MRI was obtained and to them dynamic adjusted gray levels. The extracted features of the image were standard deviation (SD), mean, and entropy of pixel intensity in the region of interest (ROI). The receiver operator characteristic (ROC) curve, 95% confidence intervals, and kappa statistics were used to test the significance and agreement. The analysis of area under ROC shows that SD, mean, and entropy in the ROI were significant between the experimental group and the control group. Smaller values of SD, mean, and entropy were associated with a higher probability of liver cirrhosis. The agreements between the extracted features and diagnostic results were shown significantly (P < 0.001). In this investigation, quantitative features of SD, mean, and entropy in the ROI were successfully computed by the dynamic gray level scaling of T2-weighted MRI with high accuracy.