ES97D Biomedical Imaging and Medical Devices 2018 Practice Paper PDF

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ES97D Biomedical Imaging and Medical Devices 2018 Practice Paper...

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ES97D0

THE UNIVERSITY OF WARWICK

MSc Examinations: Summer 2018

IMAGING & SENSING IN BODY & BRAIN

Candidates should answer ALL FIVE QUESTIONS.

Time Allowed: 3 hours.

Only calculators that conform to the list of models approved by the School of Engineering may be used in this examination. The Engineering Data Book and standard graph paper will be provided, plus one article as reference material for Question 5.

Read carefully the instructions on the answer book and make sure that the particulars required are entered on each answer book.

ES97D0 Q1. a) I-131 has a physical half-life of 8 days, yet the effective half-life of I-131 is measured to be approximately 1.6 days in a patient. Explain how this can happen, and calculate the biological half-life of I-131 in the patient. (5 marks) b) Define and describe PET, and explain how it differs from routine radionuclide imaging. In your answer, please use diagrams and concise technical explanations to show how radioactive material administered to the patient is converted into a signal that can be detected for imaging purposes, and explain the basic principles of positron emission detection. (10 marks)

c) If a scan is performed of the heart tissue after a cardiac arrest, explain what information may be obtained about the heart with X-ray CT, MRI, and PET. What critical additional information can PET provide if the heart is not in motion?

(5 marks)

Total marks = 20

_______________________________________________________________________________ Continued 1

ES97D0 Q2.

a) Briefly define, and explain the importance of PACS in medical imaging.

(2 marks)

b) When an image is digitised, what is the impact on an image of reducing it from 256 greyscale resolution to 2? Explain in detail the various ways in which this could affect the interpretation of a medical image, and use drawings to illustrate your answer. (6 marks) c) For each of the following artefacts, explain the cause, features that arise, and a potential solution to prevent the artefact arising in future.

i)

Partial volume effect in MRI

(4 marks)

ii)

Beam hardening in X-ray CT

(4 marks)

iii)

Aliasing in MRI

(4 marks)

Total marks = 20

Continued

2

ES97D0 Q3. a) Define and carefully explain the term intensity reflection coefficient, R, in the context of ultrasonic medical imaging. (3 marks)

b) Using your answer from part a), and your knowledge of the characteristic acoustic impedance for ultrasound in air, soft and hard tissue, and water, calculate typical intensity reflection coefficients for normal incidence ultrasound waves at the following three interfaces. You should comment on the practical implications for, and challenges associated with, measurement of each of these three interfaces. i)

Air: soft tissue

ii)

Soft tissue: water

iii)

Bone: soft tissue (9 marks)

c) In medical ultrasound, describe what is meant by the technique of tissue harmonic imaging, and state how it on impacts artefacts, resolution and contrast. (4 marks) d) Explain how aliasing can arise in Pulsed Flow Doppler ultrasound, and the effect on measured blood flow. (4 marks)

Total marks = 20

_______________________________________________________________________________ Continued 3

ES97D0 Q4. a) Compare and contrast routine Magnetic Resonance Imaging (e.g. T1 or T2 contrast) with Magnetic Resonance Spectroscopy Imaging (also known as Chemical Shift Imaging), highlighting the advantages and disadvantages of each method. (10 marks) b) In Figure 1 below, Magnetic Resonance Spectroscopy Imaging (MRSI) data are shown from a patient with a suspected brain tumour. Explain what type of information is being shown in each part of the image (A, B, C, and D). (6 marks)

c) Comment on how the data in Figure 1 might be used in diagnosis and surgery, and explain why displaying the intensity of the metabolite distribution (Choline to NAA ratio) as a contour plot might be considered misleading. (4 marks)

Figure 1 (from Figure 4 in Eur Biophys J (2010) 39:527–540) Total marks = 20 Continued 4

ES97D0 Q5. a) Define image registration (also called coregistration) in the context of medical imaging, and explain the basic differences between rigid body registration and spatial normalisation (also called elastic mapping or elastic deformation). (5 marks)

b) Using the paper provided as supplementary reading for this examination (Klein et al, Neuroimage, 2009), write a short article about human brain MRI registration. Your content should be clear, precise, and concise. The content should be understandable for a non-expert (e.g. an engineering student from another course). You may include your own diagrams and tables of information if this helps you to communicate your answer. As an example, your article might consider one or more of the following points:  A clear explanation about why computational algorithms (as opposed to manual segmentation) are necessary to perform human brain MRI registration.  The challenges and opportunities presented by human brain MRI registration.  An overview of the method used by Klein et al in this paper about their research.  A summary of general recommendations made by the authors based on their results. (15 marks)

Total marks = 20 _______________________________________________________________________________

END

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