The Effectiveness of Ferritin as a Contrast Agent for Cell Tracking MRI in Mouse Cancer Models

Purpose: We aimed to investigate the effectiveness of ferritin as a contrast agent and a potential reporter gene for tracking tumor cells or macrophages in mouse cancer models. Materials and methods: Adenoviral human ferritin heavy chain (Ad-hFTH) was administrated to orthotopic glioma models and subcutaneous colon cancer mouse models using U87MG and HCT116 cells, respectively. Brain MR images were acquired before and daily for up to 6 days after the intracranial injection of Ad-hFTH. In the HCT116 tumor model, MR examinations were performed before and at 6, 24, and 48 h after intratumoral injection of Ad-hFTH, as well as before and every two days after intravenous injection of ferritin-labeled macrophages. The contrast effect of ferritin in vitro was measured by MR imaging of cell pellets. MRI examinations using a 7T MR scanner comprised a T1-weighted (T1w) spin-echo sequence, T2-weighted (T2w) relaxation enhancement sequence, and T2*-weighted (T2*w) fast low angle shot sequence. Results: Cell pellet imaging of Ad-hFTH in vitro showed a strong negatively enhanced contrast in T2w and T2*w images, presenting with darker signal intensity in high concentrations of Fe. T2w images of glioma and subcutaneous HCT116 tumor models showed a dark signal intensity around or within the Ad-hFTH tumor, which was distinct with time and apparent in T2*w images. After injection of ferritin-labeled macrophages, negative contrast enhancement was identified within the tumor. Conclusion: Ferritin could be a good candidate as an endogenous MR contrast agent and a potential reporter gene that is capable of maintaining cell labeling stability and cellular safety.ope

Learning Radiologist’s Step-by-Step Skill for Cervical Spinal Injury Examination: Line Drawing, Prevertebral Soft Tissue Thickness Measurement, and Swelling Detection

Radiologists examine lateral view radiographs of the cervical spine to determine the presence of cervical spinal injury. In this paper, we demonstrate that an artificial intelligence neural network can learn the steps employed by a radiologist when examining these radiographs for possible injury. We deconstructed the decision-making strategy into three steps: line drawing, prevertebral soft tissue thickness (PSTT) measurement, and swelling detection. After training neural networks to be guided by the radiologist's intermediate labels, the networks successfully performed comparable line drawings to those of the radiologists, and subsequent PSTT measurement and swelling detection were successful. Quantitative comparison of PSTT measurements between our proposed method and radiologists showed a high correlation (r = 0.8663, p <; 0.05, and intraclass correlation coefficient = 0.9283 at the C2 level; r = 0.7720, p <; 0.05, and intraclass correlation coefficient = 0.8667 at the C6 level). Using the radiologist's diagnosis as the reference point, the sensitivity, specificity, and accuracy of swelling detection by our proposed method were 100%, 98.37%, and 98.48, respectively. We conclude that our neural networks successfully learned the sequence of skills used by radiologists when interpreting radiographs for injury of the cervical spine.ope

Cancer -Targeted MR Molecular Imaging

Magnetic resonance (MR) imaging has been widely used in the clinic because of the benefit of high spatial and temporal resolution, and the excellent anatomical tissue contrast. Cancer-targeted MR molecular imaging comprises 3 major components: a relevant molecular target which is specifically highly expressed on the membrane of the cancer cell; a target specific imaging probe which is composed of superparamagnetic iron oxide nanoparticle coreconjugated target specific ligand such as antibody, peptide, and molecules; MR imaging hardware and software which are sensitive to the imaging probe. Among the various molecular targets, HER2/neu receptor antibody, folic acid, and arginine-glycine-aspartic acid (RGD) are well known targeting ligands. The sensitivity of the cancer-targeted MR imaging is affected by the magnetic susceptibility of the T2 contrast agent, resolution of the image, targeting efficiency of the imaging probe, and image acquisition pulse sequence. Recently, successful cancer-targeted MR imaging with T1 contrast agent and cancer-specific molecular MR imaging using innate contrast of the cancer cell by chemical exchange phenomenon without using the imaging probe has been introduced. Cancer-targeted MR molecuar imaging is a robust diagnostic method to detect cancer at the cellular stage of the cancer development and it would help improve early detection rate of the cancer.ope

Clinical Feasibility of Synthetic Magnetic Resonance Imaging in the Diagnosis of Internal Derangements of the Knee

Objective: To evaluate the feasibility of synthetic magnetic resonance imaging (MRI) compared to conventional MRI for the diagnosis of internal derangements of the knee at 3T. Materials and Methods: Following Institutional Review Board approval, image sets of conventional and synthetic MRI in 39 patients were included. Two musculoskeletal radiologists compared the image sets and qualitatively analyzed the images. Subjective image quality was assessed using a four-grade scale. Interobserver agreement and intersequence agreement between conventional and synthetic images for cartilage lesions, tears of the cruciate ligament, and tears of the meniscus were independently assessed using Kappa statistics. In patients who underwent arthroscopy (n = 8), the sensitivity, specificity, and accuracy for evaluated internal structures were calculated using arthroscopic findings as the gold standard. Results: There was no statistically significant difference in image quality (p = 0.90). Interobserver agreement (kappa = 0.649- 0.981) and intersequence agreement (kappa = 0.794-0.938) were nearly perfect for all evaluated structures. The sensitivity, specificity, and accuracy for detecting cartilage lesions (sensitivity, 63.6% vs. 54.6-63.6%; specificity, 91.9% vs. 91.9%; accuracy, 83.3-85.4% vs. 83.3-85.4%) and tears of the cruciate ligament (sensitivity, specificity, accuracy, 100% vs. 100%) and meniscus (sensitivity, 50.0-62.5% vs. 62.5%; specificity, 100% vs. 87.5-100%; accuracy, 83.3-85.4% vs. 83.3-85.4%) were similar between the two MRI methods. Conclusion: Conventional and synthetic MRI showed substantial to almost perfect degree of agreement for the assessment of internal derangement of knee joints. Synthetic MRI may be feasible in the diagnosis of internal derangements of the knee.ope

Self-labeled magneto nanoprobes using tri-aminated polysorbate 80 for detection of human mesenchymal stem cells

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Quantitative T2 Mapping of Knee Cartilage: Comparison between the Synthetic MR Imaging and the CPMG Sequence

The purpose was to evaluate the feasibility of quantitative MRI T2 mapping based on the quantitative MRI (QRAPMASTER) sequence for the quantitative assessment of knee cartilage. The T2 values from the phantom study showed excellent correlation between the two techniques (r2 = 0.998). The cartilage T2 values exhibited strong correlations (r2 = 0.867-0.982). Quantitative MRI (qMRI) T2 mapping can be used as an alternative to multi-echo T2 mapping, with relatively short scan time.ope

Outcomes of Diffuse-Type Pigmented Villonodular Synovitis (PVNS) after Open Total Synovectomy

PURPOSE: Pigmented villonodular synovitis (PVNS) is a rare soft tissue tumor, which usually arises in larger joints, such as the knee. It has a high recurrence rate after surgical treatment. The purpose of this study is to evaluate and analyze the clinical results of diffuse-type pigmented villonodular synovitis cases that were treated with open total synovectomy. 0aMATERIALS AND METHODS: Between 1994 and 2006, 21 patients who had diffuse-type pigmented villonodular synovitis were selectively reviewed. Among the 21 cases studied, 14 patients presented at the knee, 5 at the ankle, and 2 at the shoulder and elbow. The mean follow up period was 5.5 years (range, 36-157 months). The average age of the patients was 34 years consist of 7 men and 14 women. Clinical outcomes were analyzed retrospectively, including range of motion and complications. 0aRESULTS: Open total synovectomy and adjuvant electrocautrization were done in all cases except one. During the regular follow-up period after the surgery, two patients showed symptoms of recurrence. After re-operation, only one case was pathologically confirmed as a recurrence. The patient who had partial synovectomy and the other patient who had second operation due to recur rence received additional radiation therapy. Clinical outcome scores were improved in every aspect (p<0.0001). 2 out of 14 Patients who had pigmented villonodular synovitis at the knee developed stiff knee after the surgery. 0aCONCLUSION: After the open total synovectomy with electrocautrization, a low recurrence rate and satisfactory clinical outcome was achieved, observed in a minimum of 3 years of follow-upope