Biomedical Instrumentation Questions and Answers – Application of Telemedicine

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This set of Biomedical Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Application of Telemedicine”.

1. Which of the following physiological parameter is most difficult to measure accurately?
a) Blood pressure
b) Blood Flow
c) Blood Volume
d) Skin color
View Answer

Answer: b
Explanation: Blood flow is one of the most important physiological parameters and also one of the most difficult to measure accurately. This is because instruments for measuring the flow through blood vessels within the body have to meet certain stringent specifications; e.g. sensitivity and stability requirements depend upon the magnitude of flow, location and the diameter of the individual vessels.
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2. Which of the following instrument is most commonly used for measurement of blood flow?
a) NMR Blood Flowmeter
b) Ultrasonic Blood Flowmeter
c) Electromagnetic Blood Flowmeter
d) Laser Doppler Blood Flowmeter
View Answer

Answer: c
Explanation: The most commonly used instrument for the measurement of blood flow is of the electromagnetic type. With this type of instrument, blood flow can be measured in intact blood vessels without cannulation and under conditions which would otherwise be impossible. However, this method requires that the blood vessel be exposed so that the flow head or the measuring probe can be put across it.

3. Magnitude of voltage picked up is denoted as e = CHVd, where H is ___________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
View Answer

Answer: b
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow,d = diameter of the blood vessel and C = constant of proportionality.
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4. Magnitude of voltage picked up is denoted as e = CHVd, where C is __________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
View Answer

Answer: c
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow, d = diameter of the blood vessel and C = constant of proportionality.

5. The induced emf is picked by point electrodes made from ______ in electromagnetic blood flowmeter.
a) copper
b) graphite
c) platinium
d) copper tungsten
View Answer

Answer: c
Explanation: In actual practice, the electromagnetic flowmeter transducer (Wyatt, 1984) is a tube of non-magnetic material to ensure that the magnetic flux does not bypass the flowing liquid and go into the walls of the tube. The tube is made of a conducting material and generally has an insulating lining to prevent short circuiting of the induced emf. The induced emf is picked up by point electrodes made from stainless steel or platinum.
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6. What is the external diameter of flow heads?
a) 0.5 mm
b) 1 mm
c) 1.5 mm
d) 2 mm
View Answer

Answer: b
Explanation: The flow head contains a slot through which the intact blood vessel can be inserted to make a snug fit. Several probes of different sizes must therefore accompany the flowmeter to match the full range of sizes of the blood vessels which have various diameters. It is naturally more difficult to construct flow heads suitable for use with very small blood vessels. However, flow heads having as small as 1 mm external diameter have been reported in the literature.

7. The operating principle underlying all electromagnetic type flowmeters is based upon Kirchoff’s law.
a) True
b) False
View Answer

Answer: b
Explanation: False, The operating principle underlying all electromagnetic type flowmeters is based upon Faraday’s law of electromagnetic induction which states that when a conductor is moved at right angles through a magnetic field in a direction at right angles both to the magnetic field and its length, an emf is induced in the conductor. In the flowmeter, an electromagnetic assembly provides the magnetic field placed at right angles to the blood vessel in which the flow is to be measured.
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8. The average flow velocity appears to be _______ cm/s in arteries.
a) 5 to 10
b) 10 to 12
c) 12 to 18
d) 20 to 25
View Answer

Answer: d
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.

9. What is the average flow velocity in veins?
a) 5 to 10 cm/s
b) 10 to 12 cm/s
c) 12 to 18 cm/s
d) 20 to 25 cm/s
View Answer

Answer: b
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.
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10. What is velocity for the cardiovascular system taken for designing the probe?
a) 5 cm/s
b) 10 cm/s
c) 15 cm/s
d) 20 cm/s
View Answer

Answer: c
Explanation: For designing the probe, velocity for the cardiovascular system is taken as 15 cm/s. For non-cannulated probes, a uniform magnetic field over the measuring area is so selected that it has a convenient shape and the smallest size (Cunningham et al. 1983).

11. Iron cored electromagnets are used in probes having a diameter between ______
a) 0.1 to 1 mm
b) 1 to 8.2 mm
c) 8.2 to 10 mm
d) 10 to 15 mm
View Answer

Answer: b
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.

12. To protect probe from chemical attack, it must be encapsulated in silicon rubber.
a) True
b) False
View Answer

Answer: a
Explanation: True, To protect the probe from chemical attack, it must be encapsulated in a biologically inert material having a high electrical and chemical resistance, e.g. silicone rubber. The probes can generally be sterilized by chemical means. Probe calibration is carried out in 0.9% saline during manufacture and each probe is given a calibration factor that is engraved on the connector.

13. The cable from the transducer to an instrument is sleeved with medical grade silicon rubber.
a) True
b) False
View Answer

Answer: a
Explanation: True, the cable from the transducer to the instrument should comprise of a teflon insulated wire completely shielded with a tinned copper braid. The entire cable is sleeved with medical grade silicone rubber tubing and impregnated with silicone rubber to minimize leakage and electrical noise.

14. Air cored electromagnets are used in probes having a diameter _________
a) between 0.5 to 1 mm
b) between 1 to 2 mm
c) below 8.2 mm
d) above 8.2 mm
View Answer

Answer: d
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.

Sanfoundry Global Education & Learning Series – Biomedical Instrumentation.

To practice all areas of Biomedical Instrumentation, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter