Allied Health sciences

I nfrared thermal imaging has been used to study non-invasive diagnosis of peripheral vascular diseases. Temperature gradients indicating abnormal blood flow in the affected regions of patients with vascular disorders are well correlated with clinical findings. The temperature in the affected regions was about 0.7-1ºC above the normal regions, due to slow blood circulation. Thermal imaging is an effective technique for detecting small temperature changes due to vascular disorders, it is non-invasive, portable, compact and safe.

Aptamers are nucleic acid/peptide molecules that can be generated by a sophisticated, well-established technique known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers can interact with their targets through structural recognition, as in antibodies, though with higher specificity. With this added advantage, they can be made useful for clinical applications such as targeted therapy and diagnosis. In this review, we have discussed the steps involved in SELEX process and modifications executed to attain high affinity nucleic acid aptamers. Moreover, our review also highlights the therapeutic applications of aptamer functionalized nanoparticles and nucleic acids as chemo-therapeutic agents. In addition, we have described the development of “aptasensor” in clinical diagnostic application for detecting cancer cells and the use of aptamers in different routine imaging techniques, such as Positron Emission Tomography/Computed Tomography, Ultrasound, and Magnetic Resonance Imaging

Cancer prognosis was mainly done by imaging and biopsy with histological analysis of solid tumours. Identifying tumour margins and staging of the tumour are critical for choosing appropriate treatments so that the risk of reoccurrence could be minimized. Imaging modalities have their strengths and limitations. Hence multimodality imaging that takes advantage of strengths from two or more imaging techniques may serve improved diagnostic and therapeutic monitoring abilities. Radiolabelled small molecules have been used as contrast agents to detect tumour for prognosticating therapeutic interventions. However, these probes lack tissue specificity and stability for optimal usage. Quantum dots (QDs) are fluorescent probes for optical imaging, which are capable of tunable optical properties, ability to target tumours when their surface-functionalized with high stability. Recently, a wide application of biocompatible surface-functionalized QDs is evidenced as multimodal imaging probes. However, their pathway to clinical translation is not yet fully explored. In this review, different biocompatible functionalized nanoprobes, their in-vivo application in animal model followed by their future possible clinical applications, recent developments of optical fluorescence imaging probes and its integration with other imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and ultrasonography (US) are discussed.

Background: The appearance of cerebral haemorrhage (CH) as common MR imaging findings raise the question of how MR image acquisition and haemorrhage area quantification can help in understanding brain pathological changes as the result of various disease conditions such as acute brain injury, hypertension amyloid angiopathy and other diverse pathology. Neuroimaging is essential for the clinician to identify the cause of haemorrhage. In this study, we examined 25 cerebral haemorrhage MR images with an objective of comparing two different sequences viz., susceptibility weighted imaging (SWI) and gradient recalled echo (GRE) on same patients and also to quantify the area of haemorrhage using manual selection and gray area threshold (automated selection) in the digital image. Materials and Methods: In this prospective study, MR images were acquired from 25 subjects with acute brain trauma (16) , hypertension (5), and amyloid angiopathy Arch Intern Med Res 2020; 3 (1): 018-025 Archives of Internal Medicine Research 19 (4), using SWI and GRE MR Sequences, with section thicknesses (3-5 mm), and magnetic field strengths (1.5T). Individual CH was manually identified and analyzed for haemorrhage area using signal intensity changes by manual and automatic selection of binary threshold hypointense signal by ImageJ software package. Results: By other parameters set as constant, we were able to quantify hypointense signal changes at regions of cerebral haemorrhage on SWI when compared to no such notable changes in GRE in the case of amyloid angiopathy patients. Apart from this, lesions prospectively identified on SWI had a significantly greater area measured on the SWI image than those not prospectively identified on GRE. Conclusions: There is an increased sensitivity in the CH detection in patients with amyloid angiopathy while using SWI sequence when compared to GRE in which we could not identify any signal changes in specific areas. Furthermore, the haemorrhage areas quantified by an automated cropping technique using ImageJ software yielded a precise lesion area method when compared to manual cropping. However, observation on increased sample size in this disease condition is required to confirm these preliminary findings to prognosticate CH.

Physiological changes due to blood oxygen level dependent (BOLD) signals from the brain can be probed by functional MRI (fMRI). Especially, several resting state fMRI (rs-fMRI) studies have evidenced the alterations in the default mode network (DMN), which is a fundamental network among the resting state networks (RSNs) with respect to progressing diminished brain function due to various disease conditions such as Alzheimer's disease (AD). Recently, there are several techniques developed to analyze the rs-fMRI data such as voxel based morphometry (VBM), i.e., seed based analysis, independent component analysis (ICA), clustering algorithm, graph method, neural networks, pattern classification method and statistical parametric mapping. Though these techniques are promising, its application on routine clinical practice is not yet developed. However, it may play a vital role in future for diagnostic and prognosticating various dementia conditions. In this review, fundamentals of rs-fMRI, different data analysis techniques such as seed-based, independent component analysis and graph theory analysis, regional homogeneity analysis and amplitudes of low-frequency fluctuations of the rs-fMRI BOLD signal are discussed.

Ultrasound imaging technique involves the use of sound waves and their echoes to produce a picture of internal organs or masses. An ultrasound transducer emits sound waves and picks up the echoes as they bounce off from the body tissue interfaces. These echoes are converted into images to display on the monitor. This imaging modality is completely non-invasive, helps in real time monitoring, it is a cost-effective, portable and versatile instrument with a wide range of clinical utility including characterizing lesions in the liver, urogenital tract, various soft tissues etc. With the introduction of micro-bubbles intravascular structures are examined based on their vascularity. In the context of cancer imaging, ultrasound is used for numerous routine screening examinations; it assists x-ray mammography, it has the ability to characterize liver lesions, with respect to urogenital tract, it helps to detect non-symptomatic cancer in prostate, uterus, ovaries, bladder and kidney. Apart from these, it helps to characterize lymph nodes by its architectural changes and shape, also helps to diagnose and staging of thyroid and neck cancers. This review gives an overview of the history and the current scenario of targeted ultrasound imaging of cancers of different tissues.