Rahul Manoj

Norwegian University of Science and Technology | NTNU · Department of Structural Engineering

Background: Imaging large volume human brains at cellular resolution involve histological methods that cause structural changes. A reference point prior to sectioning is needed to quantify these changes and is achieved by serial block face imaging (BFI) methods that have been applied to small volume tissue (~1cm^3). New method: We have developed...

Local pulse wave velocity (PWV) has gained much attention in the last decade due to its ability to provide localized stiffness information from a target vessel and cater to several applications beyond regional PWV. Transit time-based methods are the most straightforward, but their reliability is highly dependent on the blood pulse sensing modality....

Vascular ageing is directly associated with the blood vessel wall structural and functional abnormalities. Pulse morphology carries information on these abnormalities, and pulse contour analysis (PCA) identifies key amplitudes and timing information on the pulse waveforms that has a prognostic value towards cardiovascular risk stratification. PCA m...

Characteristic impedance (Zc) of the blood vessel relates the pulsatile pressure to pulsatile blood flow velocity devoid of any wave reflections. Estimation of ZC is useful for indirect evaluation of local pulse wave velocity and crucial for solving wave separation analysis (WSA) which separates the forward-backward pressure and flow velocity wavef...

Bramwell-Hill (BH) equation is widely adopted for the evaluation of local pulse wave velocity (PWV), primarily for its theoretical association with the vessel's distensibility. Its implementation, however, requires arterial pressure and diameter waveforms simultaneously from a single site. Owing to the challenges associated with such a noninvasive...

Computation of arterial stiffness is a well-established, widely accepted method for estimating vascular age. Although carotid-femoral pulse wave velocity is typically used for vascular age assessment, most recent studies have reported the need to consider a combination of local and regional stiffness indices possessing distinct association with the...

Objective: Methods for separating the forward-backward components from blood pulse waves rely on simultaneously measured pressure and flow velocity from a target artery site. Modelling approaches for flow velocity simplify the wave separation analysis (WSA), providing a methodological and instrumentational advantage over the former; however, curre...

Cardiovascular community has started clinically adopting the assessment of local stiffness, contrary to the traditionally measured carotid-femoral pulse wave velocity (PWV). Though they offer higher reliability, ultrasound methods require advanced hardware and processing methods to perform real-time measurement of local PWV. This work presents a sy...

Capturing vascular dynamics using ultrasound at a high framerate provided a unique way to track time-dependent and transient physiologic events non-invasively. In this work, we present an A-model high-framerate (500 frames per second) image-free ultrasound system for monitoring vascular structural and material properties. It was developed based on...

The arterial pulse waveform has an immense wealth of information in its morphology yet to be explored and translated to clinical practice. Wave separation analysis involves decomposing a pulse wave (pressure or diameter waveform) into a forward wave and a backward wave. The backward wave accumulates reflections due to arterial stiffness gradient, b...

Conventional methods to calculate reflection transit time (RTT) is based on pulse counter analysis. An alternative to this approach is separating forward and backward components from a pulse waveform to calculate the RTT. State-of-the-art in wave separation requires simultaneously measured pressure and flow velocity waveforms. Practically, getting...

Background: Arterial stiffness index (β) is a clinically accepted vascular metric, calculated from arterial pressure and diameter obtained simultaneously from a single arterial site [1]. Hence, accurate measurement of β can only be performed on arteries where pressure can be recorded along with the diameter. We present a method to evaluate β from s...

Pulse wave velocity (PWV) is a function of the artery's material property, and its incremental nature in elastic modulus led to the concept of incremental PWV. Recent advancements in technology paved the way for reliable measurement of the variation in PWV within a cardiac cycle. This change in PWV has shown its potential as a biomarker for advance...

Intervention in the early stages of cardiovascular and kidney diseases is proven to be more effective in preventing disease progression. Large artery stiffness measurement can be a potential early predictor of future risks. The purpose of the study reported in this work was to demonstrate the feasibility of our ARTSENS® Pen device as a high-through...