A Promising Discussion with my External Guide and Some Concerns

12:35 pm

Yesterday, my External Guide replied to the mail I had sent him, stating the problems that I'm having primarily based on Data Acquisition. In his reply, he wished to have a discussion regarding the project over the telephone.

In the discussion, we spoke about the following:

1. Problems with Data Acquisition directly from the patient

2. Solution to the problem using laboratory simulations of the patient.

3. An outline of the laboratory procedure

4. Availability of the necessary Laboratory Equipment

5. Planned timeline

Problems with Data Acquisition directly from the patient 

• If we collect data from an ultrasound machine from patients, there are a lot of variables. The patients could be having various types of diseases. Analysis would be influenced by the disease conditions that the patients have. Thus, validation of signal processing will become very tough. Anyone could challenge the reliability on the outcome of the processed signal. 

• Also, it is very common that, in a patient, during observation, a blood vessel suddenly changes its diameter or the baby itself moves within the within the womb, as a result of which getting steady readings is highly impossible. Also, the velocities the doctors get in the morning are completely different from what they get in the evening. Many a times readings diagnosed as abnormal in the morning, may be normal in the evening with the same patient. So, taking steady readings requires a very detailed kind of an examination, on patients. 

• Also limited by, regulatory requirements of taking patient's consent, unnecessarily delay. 

• Analysis would be influenced also by the amount of data we collect. 

• Before going to the patients , it is always a good idea to do the lab test. 

• In the lab we can have simulated conditions, and thus, actually compare the signal processing techniques with a simulated flow that we simulate. Therefore you will have a greater confidence in saying that the applied processing techniques, and the results that are being obtained from those techniques, are actually matching. This becomes the proof. 

• Additionally, there are many other parameters which are not being measured in a doppler study. For example Doppler signal is a map of fluid velocities at different times. As the fluid velocities change, the doppler signal also changes. But, it is very difficult to analyse, from just knowing the fluid velocities, what the pressure changes are present in the vessels, due to which the fluid velocities change. But if we have a simulated flow, then you can actually measure them.

• Then we will be able to arrive at some kind of a relation, between the doppler signal and pressure measurement or the pressure distance between different of the pipe which is emulating the artery. 

• In this way, if we can identify more parameters than just the flows, using the flow signal itself then we can extrapolate the knowledge of changing flows, and map the causes to probably the pressure difference, may be the vascular resistance, or may be the diameter of the vessel or suddenly changes. 

• This is the reason why we decide to keep the patient studies for a later stage in the project. 

An Outline of the Laboratory Procedure 

• We need to collect some form of a data of flowing fluid, analyze that data, and from that data analysis we are trying to characterize, the flow.

• Thus, we need a laboratory set up, where you can actually have flowing fluid. To collect or read the data we’ll need an ultrasound, or a doppler flowmeter. 

• To emulate the flow in a lab, we need to make the setup in such a way, that, it resembles the actual physiological pulsatile flow in an artery. We can have various physiological scenarios that we could simulate on such a model, and thus the working conditions would be in our control, that is, we’ll have a control environment. 

• We could change the scenarios based on different values of flow rates, pressure differences between the two ends of the pipe, and pulsatile magnitude. 

• Now, if we acquire the signal using the flowmeter, and apply the signal processing techniques, we can actually validate your technique, because, we are having a control environment. 

• This would give us a very good understanding of the flows within the vessels and so on. 

• Thus, this point can become a very good validation point. and we can always very well defend a thesis that we can validate. 

The Availability of Necessary Laboratory Equipment 

• We could design the experiment and the setup necessary, but the equipment required has to be available. 

• Also, it becomes altogether simpler if the particular laboratory technician is able to help out with setting up of the experiment. 

• The second chapter of the thesis should be on these you know setting up the lab simulating lab. eg, is it the umbilical artery flow that we are trying to simulate or the middle cerebral artery flow? Accordingly the pulsatality could be kept at 72 beats per minute or 140 beats per minute. As such, what all are the configurations possible? etc. 

• Need a flowmeter which will suffice to our conditions, so need to select a flowmeter with a suitable specification. 

• We need to prove it that the the experimental setup, is the best possible that we could have for the specified simulation conditions. 

Planned Timeline 

• The Data Acquisition stage normally takes around 2 months. 

• In the 3rd month, may be by December, we should be able to acquire the data and perform the first set of simulated experiments. 

My concerns:

1. Do we have the facilities available here in Goa College of Engineering? Like in the departments eg, Mechanical department..? Or will I have to go to IIT Bombay? Is that possible?

2. Does the project still remain based on audio Doppler,.. since that is included in the name of the project.