Imaging Biomarker For Diagnosis Research Articles

Microvascular changes in the macular and parafoveal areas of multiple sclerosis patients without optic neuritis

Retinal imaging has been proposed as a biomarker for neurological diseases such as multiple sclerosis (MS). Recently, a technique for non-invasive assessment of the retinal microvasculature called optical coherence tomography angiography (OCTA) was introduced. We investigated retinal microvasculature alterations in participants with relapsing–remitting MS (RRMS) without history of optic neuritis (ON) and compared them to a healthy control group. The study was performed in a prospective, case–control design, including 58 participants (n = 100 eyes) with RRMS without ON and 78 age- and sex-matched control participants (n = 136 eyes). OCTA images of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 Spectral-Domain OCT with AngioPlex OCTA, Carl Zeiss Meditec, Dublin, CA). The outcome variables were perfusion density (PD) and foveal avascular zone (FAZ) features (area and circularity) in both the SCP and DCP, and flow deficit in the CC. MS group had on average higher intraocular pressure (IOP) than controls (P < 0.001). After adjusting for confounders, MS participants showed significantly increased PD in SCP (P = 0.003) and decreased PD in DCP (P < 0.001) as compared to controls. A significant difference was still noted when large vessels (LV) in the SCP were removed from the PD calculation (P = 0.004). Deep FAZ was significantly larger (P = 0.005) and less circular (P < 0.001) in the eyes of MS participants compared to the control ones. Neither LV, PD or FAZ features in the SCP, nor flow deficits in the CC showed any statistically significant differences between the MS group and control group (P > 0.186). Our study indicates that there are microvascular changes in the macular parafoveal retina of RRMS patients without ON, showing increased PD in SCP and decreased PD in DCP. Further studies with a larger cohort of MS patients and MRI correlations are necessary to validate retinal microvascular changes as imaging biomarkers for diagnosis and screening of MS.

Imaging biomarkers for diagnosis and treatment response in patients with lymphedema.

Lymphedema is defined as a dysfunction of the lymphatic system producing an accumulation of lymphatic fluid in the surrounding tissue, as well as edema and fibrosis. A total of250million people worldwide are affected by this condition. Greater than 99% of these cases are related to a secondary cause. As there is a lack of curative therapy, the goal involves early diagnosis, in order to prevent the progression of the disease. Additionally, early diagnosis can aid in decreasing the demand for more complex surgical procedures. Currently, there is an impressive breadth of diagnostic tests available for these patients. We aimed to review the available literature in relation to the utilization of imaging biomarkers for the early diagnosis and treatment response in lymphedema.

Comparison of Conventional and Radiomic Features between 18F-FBPA PET/CT and PET/MR.

Boron-10-containing positron emission tomography (PET) radio-tracer, 18F-FBPA, has been used to evaluate the feasibility and treatment outcomes of Boron neutron capture therapy (BNCT). The clinical use of PET/MR is increasing and reveals its benefit in certain applications. However, the PET/CT is still the most widely used modality for daily PET practice due to its high quantitative accuracy and relatively low cost. Considering the different attenuation correction maps between PET/CT and PET/MR, comparison of derived image features from these two modalities is critical to identify quantitative imaging biomarkers for diagnosis and prognosis. This study aimed to investigate the comparability of image features extracted from 18F-FBPA PET/CT and PET/MR. A total of 15 patients with malignant brain tumor who underwent 18F-FBPA examinations using both PET/CT and PET/MR on the same day were retrospectively analyzed. Overall, four conventional imaging characteristics and 449 radiomic features were calculated from PET/CT and PET/MR, respectively. A linear regression model and intraclass correlation coefficient (ICC) were estimated to evaluate the comparability of derived features between two modalities. Features were classified into strong, moderate, and weak comparability based on coefficient of determination (r2) and ICC. All of the conventional features, 81.2% of histogram, 37.5% of geometry, 51.5% of texture, and 25% of wavelet-based features, showed strong comparability between PET/CT and PET/MR. With regard to the wavelet filtering, radiomic features without filtering (61.2%) or with low-pass filtering (59.2%) along three axes produced strong comparability between the two modalities. However, only 8.2% of the features with high-pass filtering showed strong comparability. The linear regression models were provided for the features with strong and moderate consensus to interchange the quantitative features between the PET/CT and the PET/MR. All of the conventional and 71% of the radiomic (mostly histogram and texture) features were sufficiently stable and could be interchanged between 18F-FBPA PET with different hybrid modalities using the proposed equations. Our findings suggested that the image features high interchangeability may facilitate future studies in comparing PET/CT and PET/MR.

Quantification of Coronary Inflammation Using Fat Attenuation Index (FAI) in Indians: A Retrospective Study

<i>Background</i>: Asian Indians have the highest prevalence (11%) of coronary artery risk worldwide compared to all other races. So far no quantifiable risk factor has been shown to explain such a high prevalence. Fat attenuation index (FAI) using CT coronary angiography (CTCA) has been recently used to demonstrate coronary perivascular inflammation and to confirm that atherosclerosis is an inflammatory process. Hence this study was conducted to determine FAI using CTCA in 200 adult Indians as a retrospective study to determine if it can be the answer to establish the cause for high prevalence of CAD in Indians and whether there are differences in FAI in normal adults and those with significant CAD and to determine if it could be used as imaging biomarker for diagnosis and follow up of such patients. <i>Material and Methods</i>: Retrospective study of 200 patients who underwent CTCA was done. Patients were divided into two groups based on no coronary disease (NOCAD) and those with significant coronary artery disease (CAD). Patient demographics were recorded for both groups. FAI estimation was done along with Plaque volume index (PVI), pericardial volume estimation and the differences between the two groups were statistically analysed. <i>Results</i>: Mean patient age in both groups was 52 years with male predominance (75-80%). Mean FAI,s for left anterior descending and right coronary arteries was 45.4 and -44.7 HU and of -38.0 and -39.2 HU for NOCAD and CAD groups respectively (p<0.001). Sensitivity and specificity of FAI to differentiate NOCAD from CAD at a cut off value >-38HU was 73% and 80% respectively with LR of 3.6. <i>Conclusion</i>: Normal adult Indians with NOCAD showed a high FAI compared to all other races which could be reason for highest prevalence of CAD amongst Indians. FAI can be used as imaging biomarker to differentiate CAD from NOCAD with sensitivity and specificity of 73% and 80% respectively.

Radiomics in Lung Cancer from Basic to Advanced: Current Status and Future Directions.

Ideally, radiomics features and radiomics signatures can be used as imaging biomarkers for diagnosis, staging, prognosis, and prediction of tumor response. Thus, the number of published radiomics studies is increasing exponentially, leading to a myriad of new radiomics-based evidence for lung cancer. Consequently, it is challenging for radiologists to keep up with the development of radiomics features and their clinical applications. In this article, we review the basics to advanced radiomics in lung cancer to guide young researchers who are eager to start exploring radiomics investigations. In addition, we also include technical issues of radiomics, because knowledge of the technical aspects of radiomics supports a well-informed interpretation of the use of radiomics in lung cancer.

A Functional Study of Human Inflammatory Arthritis Using Photoacoustic Imaging

By using our dual-modality system enabling simultaneous real-time ultrasound (US) and photoacoustic (PA) imaging of human peripheral joints, we explored the potential contribution of PA imaging modality to rheumatology clinic. By performing PA imaging at a single laser wavelength, the spatially distributed hemoglobin content reflecting the hyperemia in synovial tissue in metacarpophalangeal (MCP) joints of 16 patients were imaged, and compared to the results from 16 healthy controls. In addition, by performing PA imaging at two laser wavelengths, the spatially distributed hemoglobin oxygenation reflecting the hypoxia in inflammatory joints of 10 patients were imaged, and compared to the results from 10 healthy controls. The statistical analyses of the PA imaging results demonstrated significant differences (p < 0.001) in quantified hemoglobin content and oxygenation between the unequivocally arthritic joints and the normal joints. Increased hyperemia and increased hypoxia, two important physiological biomarkers of synovitis reflecting the increased metabolic demand and the relatively inadequate oxygen delivery in affected synovium, can both be objectively and non-invasively evaluated by PA imaging. The proposed dual-modality system has the potential of providing additional diagnostic information over the traditional US imaging approaches and introducing novel imaging biomarkers for diagnosis and treatment evaluation of inflammatory arthritis.

Aberrant Brain Regional Homogeneity and Functional Connectivity in Middle-Aged T2DM Patients: A Resting-State Functional MRI Study.

Type 2 diabetes mellitus (T2DM) has been associated with cognitive impairment. However, its neurological mechanism remains elusive. Combining regional homogeneity (ReHo) and functional connectivity (FC) analyses, the present study aimed to investigate brain functional alterations in middle-aged T2DM patients, which could provide complementary information for the neural substrates underlying T2DM-associated brain dysfunction. Twenty-five T2DM patients and 25 healthy controls were involved in neuropsychological testing and structural and resting-state functional magnetic resonance imaging (rs-fMRI) data acquisition. ReHo analysis was conducted to determine the peak coordinates of brain regions with abnormal local brain activity synchronization. Then, the identified brain regions were considered as seeds, and FC between these brain regions and global voxels was computed. Finally, the potential correlations between the imaging indices and neuropsychological data were also explored. Compared with healthy controls, T2DM patients exhibited higher ReHo values in the anterior cingulate gyrus (ACG) and lower ReHo in the right fusiform gyrus (FFG), right precentral gyrus (PreCG) and right medial orbit of the superior frontal gyrus (SFG). Considering these areas as seed regions, T2DM patients displayed aberrant FC, mainly in the frontal and parietal lobes. The pattern of FC alterations in T2DM patients was characterized by decreased connectivity and positive to negative or negative to positive converted connectivity. Digital Span Test (DST) forward scores revealed significant correlations with the ReHo values of the right PreCG (ρ = 0.527, p = 0.014) and FC between the right FFG and middle temporal gyrus (MTG; ρ = −0.437, p = 0.048). Our findings suggest that T2DM patients suffer from cognitive dysfunction related to spatially local and remote brain activity synchronization impairment. The patterns of ReHo and FC alterations shed light on the mechanisms underlying T2DM-associated brain dysfunction and might serve as imaging biomarkers for diagnosis and evaluation.

Abstract WP428: Changes of Microstructural White Matter in Vascular Cognitive Disorder and Amnestic Mild Cognitive Impairment: a Diffusion Tensor Imaging Study

Background: White matter (WM) damage could be observed in both vascular cognitive disorder predementia (VCD-P) and amnestic mild cognitive impairment (aMCI). In the period of VCD-P, the degree of cognitive decline was similar to aMCI, but they are different in the specific cognitive domains. However whether the differences in cognitive domains are related to the pattern of WM impairment hasn’t been illustrated. Hypothesized: The region or degree of WM impairment differs from VCD-P to aMCI. Methods: All subjects include 28 patients with VCD-P, 34 aMCI and 39 normal controls (NC) underwent a comprehensive neuropsychological assessment and DTI. We compared fractional anisotropy (FA), mean diffusivity (MD) and axial diffusivity (AxD) of whole brain WM regions. Then the diffusion tensor was reconstructed, analyzed by tract-based spatial statistics. Results: Patient groups exhibited significant differences in FA, MD and AxD, the VCD-P group has a lower FA, higher MD and AxD. The different FA and MD region between VCD-P and aMCI was in left anterior limb of internal capsule, bilateral corona radiata, corpus callosum, cerebral peduncle, external capsule, posterior limb of internal capsule, fornix, inferior longitidinal fasciculus, inferior and superior fronto-occipital fasciculus, whereas in AxD it was showed in bilateral corona radiata, internal capsule, external capsule, corpus callosum, posterior thalamic radiation and superior longitudinal fasciculus. Conclusion: Our findings suggest that VCD-P and aMCI have divergent topography of WM microstructural changes in the degree and the region, the WM integrity was impaired more severe in VCD-P. The differences in regions may illustrate the clinical and neuropsychological features characterized by executive or memory deficit. These findings provide insights into the biological mechanism of cognitive disorders and highlight the potential of DTI as the imaging biomarker for diagnosis. All authors report no conflicts of interest. This work was supported by the National Natural Science Funds of China (Grant No. 81301188).

Serial MRI Features of Canine GM1 Gangliosidosis: A Possible Imaging Biomarker for Diagnosis and Progression of the Disease

GM1 gangliosidosis is a fatal neurodegenerative lysosomal storage disease caused by an autosomal recessively inherited deficiency of β-galactosidase activity. Effective therapies need to be developed to treat the disease. In Shiba Inu dogs, one of the canine GM1 gangliosidosis models, neurological signs of the disease, including ataxia, start at approximately 5 months of age and progress until the terminal stage at 12 to 15 months of age. In the present study, serial MR images were taken of an affected dog from a model colony of GM1 gangliosidosis and 4 sporadic clinical cases demonstrating the same mutation in order to characterize the MRI features of this canine GM1 gangliosidosis. By 2 months of age at the latest and persisting until the terminal stage of the disease, the MR findings consistently displayed diffuse hyperintensity in the white matter of the entire cerebrum on T2-weighted images. In addition, brain atrophy manifested at 9 months of age and progressed thereafter. Although a definitive diagnosis depends on biochemical and genetic analyses, these MR characteristics could serve as a diagnostic marker in suspect animals with or without neurological signs. Furthermore, serial changes in MR images could be used as a biomarker to noninvasively monitor the efficacy of newly developed therapeutic strategies.

Imaging biomarkers for diagnosis and quantification with positron emission tomography: assistance to therapy

Imaging biomarkers for diagnosis and quantification with positron emission tomography : assistance to therapy