ABSTRACT
This study shows how applying compressed sensing (CS) to (19)F chemical shift imaging (CSI) makes highly accurate and reproducible reconstructions from undersampled datasets possible. The missing background signal in (19)F CSI provides the required sparsity needed for application of CS. Simulations were performed to test the influence of different CS-related parameters on reconstruction quality. To test the proposed method on a realistic signal distribution, the simulation results were validated by ex vivo experiments. Additionally, undersampled in vivo 3D CSI mouse datasets were successfully reconstructed using CS. The study results suggest that CS can be used to accurately and reproducibly reconstruct undersampled (19)F spectroscopic datasets. Thus, the scanning time of in vivo(19)F CSI experiments can be significantly reduced while preserving the ability to distinguish between different (19)F markers. The gain in scan time provides high flexibility in adjusting measurement parameters. These features make this technique a useful tool for multiple biological and medical applications.
Subject(s)
Fluorine/chemistry , Magnetic Resonance Imaging/methods , Algorithms , Animals , Artifacts , Computer Simulation , Data Interpretation, Statistical , Image Processing, Computer-Assisted , Ischemic Attack, Transient/pathology , Mice , Mice, Inbred C57BL , Phantoms, Imaging , Reference Values , Reproducibility of Results , Thrombosis/pathologyABSTRACT
BACKGROUND: Patients with melanoma-associated retinopathy (MAR) experience different visual symptoms caused by the production of antitumoral antibodies that cross-react with retinal epitopes. Immunofluorescence assays of serum from patients with MAR on sectioned monkey or human retina characteristically reveal antibody activity located within the inner nuclear layer, with a focus of activity upon the membranes of bipolar cells. OBJECTIVES: We inquired into the association with disease of this serological abnormality by evaluating sera from patients with melanoma with no MAR-like signs or symptoms. METHODS: Groups of patients were selected with different stages of melanoma (American Joint Committee on Cancer stages I-IV). Seventy-seven serum samples from 51 patients with melanoma were examined by indirect immunohistochemical assay on sections of human retina. RESULTS: Of the 77 serum samples, 53 were found to contain antibodies reactive with various components of retina. Eight were from 17 sera from patients in stage I or II, 14 were from 23 sera from patients in stage III, and 31 were from 37 sera from patients in stage IV. Statistical analysis revealed a correlation between antibody activity and the stage of disease, with a higher percentage of antibody activity in advanced stages (P = 0.002). CONCLUSIONS: The presence of antiretinal antibodies in patients with melanoma without ocular symptoms appears to be more common than previously suspected. Antibody activity similar to that ascribed to the MAR syndrome appears in some patients with melanoma who have no MAR-like retinopathy. Follow-up studies will determine if patients with antiretinal antibodies go on to develop MAR and if staining intensity and staining patterns change over the course of the disease.
