Browsing by Subject "Molecular imaging"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Advances in Optical Contrast Agents for Medical Imaging: Fluorescent Probes and Molecular Imaging
    (MDPI, 2025-03-18) Tripathi, Divya; Hardaniya, Mayurakshi; Pande, Suchita; Maity, Dipak; Chemistry and Chemical Biology, School of Science
    Optical imaging is an excellent non-invasive method for viewing visceral organs. Most importantly, it is safer as compared to ionizing radiation-based methods like X-rays. By making use of the properties of photons, this technique generates high-resolution images of cells, molecules, organs, and tissues using visible, ultraviolet, and infrared light. Moreover, optical imaging enables real-time evaluation of soft tissue properties, metabolic alterations, and early disease markers in real time by utilizing a variety of techniques, including fluorescence and bioluminescence. Innovative biocompatible fluorescent probes that may provide disease-specific optical signals are being used to improve diagnostic capabilities in a variety of clinical applications. However, despite these promising advancements, several challenges remain unresolved. The primary obstacle includes the difficulty of developing efficient fluorescent probes, and the tissue autofluorescence, which complicates signal detection. Furthermore, the depth penetration restrictions of several imaging modalities limit their use in imaging of deeper tissues. Additionally, enhancing biocompatibility, boosting fluorescent probe signal-to-noise ratios, and utilizing cutting-edge imaging technologies like machine learning for better image processing should be the main goals of future research. Overcoming these challenges and establishing optical imaging as a fundamental component of modern medical diagnoses and therapeutic treatments would require cooperation between scientists, physicians, and regulatory bodies.
  • Thumbnail Image
    Item
    Androgen-independent Molecular Imaging Vectors to Detect Castration-Resistant and Metastatic Prostate Cancer
    (American Association for Cancer Research, 2011) Jiang, Ziyue Karen; Sato, Makoto; Wei, Liu H.; Kao, Chinghai; Wu, Lily; Urology, School of Medicine
    Prostate-specific promoters are frequently employed in gene-mediated molecular imaging and therapeutic vectors to diagnose and treat castration-resistant prostate cancer (CRPC) that emerges from hormone ablation therapy. Many of the conventional prostate-specific promoters rely on the androgen axis to drive gene expression. However, considering the cancer heterogeneity and varying androgen receptor status, we herein evaluated the utility of prostate-specific enhancing sequence (PSES), an androgen-independent promoter in CRPC. The PSES is a fused enhancer derived from the prostate-specific antigen (PSA) and prostate-specific membrane antigen gene regulatory region. We augmented the activity of PSES by the two-step transcriptional amplification (TSTA) system to drive the expression of imaging reporter genes for either bioluminescent or positron emission tomography (PET) imaging. The engineered PSES-TSTA system exhibits greatly elevated transcriptional activity, androgen independency, and strong prostate specificity, verified in cell culture and preclinical animal experimentations. These advantageous features of PSES-TSTA elicit superior gene expression capability for CRPC in comparison with the androgen-dependent PSA promoter-driven system. In preclinical settings, we showed robust PET imaging capacity of PSES-TSTA in a castrated prostate xenograft model. Moreover, intravenous administrated PSES-TSTA bioluminescent vector correctly identified tibial bone marrow metastases in 9 of 9 animals, whereas NaF- and FDG-PET was unable to detect the lesions. Taken together, this study showed the promising utility of a potent, androgen-independent, and prostate cancer-specific expression system in directing gene-based molecular imaging in CRPC, even in the context of androgen deprivation therapy.
  • Thumbnail Image
    Item
    KL-VS heterozygosity is associated with lower amyloid-dependent tau accumulation and memory impairment in Alzheimer’s disease
    (Springer Nature, 2021-06-22) Neitzel, Julia; Franzmeier, Nicolai; Rubinski, Anna; Dichgans, Martin; Brendel, Matthias; Alzheimer’s Disease Neuroimaging Initiative (ADNI); Malik, Rainer; Ewers, Michael; Radiology and Imaging Sciences, School of Medicine
    Klotho-VS heterozygosity (KL-VShet) is associated with reduced risk of Alzheimer's disease (AD). However, whether KL-VShet is associated with lower levels of pathologic tau, i.e., the key AD pathology driving neurodegeneration and cognitive decline, is unknown. Here, we assessed the interaction between KL-VShet and levels of beta-amyloid, a key driver of tau pathology, on the levels of PET-assessed neurofibrillary tau in 551 controls and patients across the AD continuum. KL-VShet showed lower cross-sectional and longitudinal increase in tau-PET per unit increase in amyloid-PET when compared to that of non-carriers. This association of KL-VShet on tau-PET was stronger in Klotho mRNA-expressing brain regions mapped onto a gene expression atlas. KL-VShet was related to better memory functions in amyloid-positive participants and this association was mediated by lower tau-PET. Amyloid-PET levels did not differ between KL-VShet carriers versus non-carriers. Together, our findings provide evidence to suggest a protective role of KL-VShet against amyloid-related tau pathology and tau-related memory impairments in elderly humans at risk of AD dementia.
  • Thumbnail Image
    Item
    Label-Free Bond-Selective Imaging by Listening to Vibrationally Excited Molecules
    (American Physical Society, 2011) Wang, Han-Wei; Chai, Ning; Wang, Pu; Hu, Song; Dou, Wei; Umulis, David; Wang, Lihong V.; Sturek, Michael; Lucht, Robert; Cheng, Ji-Xin; Cellular and Integrative Physiology, School of Medicine
    We report the realization of vibrational photoacoustic (VPA) microscopy using optical excitation of molecular overtone vibration and acoustic detection of the resultant pressure transients. Our approach eliminates the tissue scattering problem encountered in near-infrared spectroscopy and enables depth-resolved signal collection. The 2nd overtone of the CH bond stretch around 8300 cm(-1), where blood interference is minimal, is excited. We demonstrate 3D VPA imaging of lipid-rich atherosclerotic plaques by excitation from the artery lumen, and lipid storage in live Drosophila larvae, with millimeter scale penetration depth [corrected].
  • Thumbnail Image
    Item
    Multivariate statistical differentiation of renal cell carcinomas based on lipidomic analysis by ambient ionization imaging mass spectrometry
    (Springer, 2010) Dill, Allison L.; Eberlin, Livia S.; Zheng, Cheng; Costa, Anthony B.; Ifa, Demian R.; Cheng, Liang; Masterson, Timothy A.; Koch, Michael O.; Vitek, Olga; Cooks, R. Graham; Pathology and Laboratory Medicine, School of Medicine
    Desorption electrospray ionization (DESI) mass spectrometry (MS) was used in an imaging mode to interrogate the lipid profiles of thin tissue sections of 11 sample pairs of human papillary renal cell carcinoma (RCC) and adjacent normal tissue and nine sample pairs of clear cell RCC and adjacent normal tissue. DESI-MS images showing the spatial distributions of particular glycerophospholipids (GPs) and free fatty acids in the negative ion mode were compared to serial tissue sections stained with hematoxylin and eosin (H&E). Increased absolute intensities as well as changes in relative abundance were seen for particular compounds in the tumor regions of the samples. Multivariate statistical analysis using orthogonal projection to latent structures treated partial least square discriminate analysis (PLS-DA) was used for visualization and classification of the tissue pairs using the full mass spectra as predictors. PLS-DA successfully distinguished tumor from normal tissue for both papillary and clear cell RCC with misclassification rates obtained from the validation set of 14.3% and 7.8%, respectively. It was also used to distinguish papillary and clear cell RCC from each other and from the combined normal tissues with a reasonable misclassification rate of 23%, as determined from the validation set. Overall DESI-MS imaging combined with multivariate statistical analysis shows promise as a molecular pathology technique for diagnosing cancerous and normal tissue on the basis of GP profiles.
  • Thumbnail Image
    Item
    The tauopathies: Neuroimaging characteristics and emerging experimental therapies
    (Wiley, 2022) Riley, Kalen J.; Graner, Brian D.; Veronesi, Michael C.; Radiology and Imaging Sciences, School of Medicine
    The tauopathies are a heterogeneous group of neurodegenerative disorders in which the prevailing underlying disease process is intracellular deposition of abnormal misfolded tau protein. Diseases often categorized as tauopathies include progressive supranuclear palsy, chronic traumatic encephalopathy, corticobasal degeneration, and frontotemporal lobar degeneration. Tauopathies can be classified through clinical assessment, imaging findings, histologic validation, or molecular biomarkers tied to the underlying disease mechanism. Many tauopathies vary in their clinical presentation and overlap substantially in presentation, making clinical diagnosis of a specific primary tauopathy difficult. Anatomic imaging findings are also rarely specific to a single tauopathy, and when present may not manifest until well after the point at which therapy may be most impactful. Molecular biomarkers hold the most promise for patient care and form a platform upon which emerging diagnostic and therapeutic applications could be developed. One of the most exciting developments utilizing these molecular biomarkers for assessment of tau deposition within the brain is tau‐PET imaging utilizing novel ligands that specifically target tau protein. This review will discuss the background, significance, and clinical presentation of each tauopathy with additional attention to the pathologic mechanisms at the protein level. The imaging characteristics will be outlined with select examples of emerging imaging techniques. Finally, current treatment options and emerging therapies will be discussed. This is by no means a comprehensive review of the literature but is instead intended for the practicing radiologist as an overview of a rapidly evolving topic.
  • Thumbnail Image
    Item
    Zeroing In on the Target
    (Elsevier, 2022) Loria, Chelsea; Denlinger, Chadrick E.; Medicine, School of Medicine