This document summarizes several diagnostic radiology techniques for imaging the head, brain, chest, and heart. It discusses proton MR spectroscopy and its use in evaluating metabolic alterations in tissues like tumors. It describes noninvasive angiographic techniques like MR angiography (MRA) and its applications. MRA uses magnetic fields and radio waves to evaluate blood vessels. The document outlines time-of-flight MRA methods and contrast-enhanced TOF MRA. It also discusses phase contrast MRA and how it encodes flow velocity in the MR signal. Functional MRI is summarized as measuring small blood flow changes with brain activity to determine brain function and map critical areas. Diffusion weighted imaging is introduced as measuring random water molecule motion.

1. Diagnostic applications of
Radiology

2. Diagnostic applications of Radiology: Current neuroimaging options for Head and Brain: Proton MR
spectroscopy, Noninvasive Angiographic techniques, Diffusion weighted imaging, Functional MRI,
Imaging modalities for Chest, Radiographic findings in chest diseases - Case study
(Seminar/Assignment) - Pulmonary Edema/Hemorrhage and vasculitis/Tumors; Breast Radiology:
Technical factors in screening - Use of other modalities - Screening ultrasound, Functional imaging;
Imaging techniques for Cardiac radiology - Echocardiography, Nuclear imaging, Cardiac CT and MRI,
Case study (Seminar/Assignment) - Coronary Artery anomalies, Cardiac Tumors; Interventional
radiology and angiography

4. Neuroimaging
Neuroimaging is the use of quantitative (computational) techniques to study the structure
and function of the central nervous system.
Neuroimaging techniques can be classified into two approaches
● Structural imaging, Structural imaging refers to approaches that are
specialized for the visualization and analysis of anatomical properties of
the brain. Structural approaches are particularly useful for detecting brain
damage and abnormalities.e,g, voxel based morphometry.
● Functional imaging, which is used to study brain function, often using
fMRI

9. PROTON MR SPECTROSCOPY
● Proton MR spectroscopy (H-MRS) is one of the ultrahigh MR imaging
technique that has been used to evaluate the metabolic alterations of tissues.
● To observe metabolite changes for different intracranial pathologies such as
tumors, multiple sclerosis, stroke, tuberculomas, epilepsy, metabolic and
inherited brain disorders, and traumatic injuries
● Various matters which have different electrical charges will have different
velocities in a certain magnetic field which may provide the measurement of
various metabolites
● The strength of the MR signal is directly proportional to the number of protons
of that frequency in spectroscopy, spectroscopy can be described in the time
domain, whereas MRS data is usually displayed in the frequency domain,
area under a specific peak in the frequency domain is proportional to the
number of protons,resonating at that certain frequency

10. Basics of MRS

17. MR Angiography (MRA)
MR angiography (MRA) uses a powerful magnetic field, radio waves and a
computer to evaluate blood vessels and help identify abnormalities
● Arterial aneurysm (an abnormal widening or ballooning of a part of an artery due to weakness in the
wall of the blood vessel)
● Aortic coarctation
● Aortic dissection
● Stroke
● Carotid artery disease
● Atherosclerosis of the arms or legs
● Heart disease, including congenital heart disease
● Mesenteric artery ischemia
● Renal artery stenosis (narrowing of the blood vessels in the kidneys)

20. TIME-OF-FLIGHT METHODS
TOF in MRI is based on the idea that T1 of flowing water is effectively shorter than
T1 of stationary water. The difference could be attributed to the fact that, when
stationary, the spins would be saturated by the radiofrequency excitation but when
flowing, fresh spins with full magnetization would replace the stationary spins,
thereby increasing the signal.
Let us combine the idea of spin saturation with the fact that moving spins have a
shorter T1 than stationary spins to construct images based on the concept of TOF.

22. CONTRAST-ENHANCED TOFMRA
Contrast-enhanced (CE) MRA uses T1 shortening agents such as gadolinium to
further increase the contrast between blood and tissue in a TOF MRA study.

24. PHASE CONTRAST MRA
In PC MR, the velocity of flow is encoded in the phase of the MR signal, providing a
mechanism of not only visualizing flow but also the ability to quantify it.
Two images are required to complete the calculation. First, the velocity-sensitive
sequence is used to generate velocity-encoded phase images for a specific direction,
as discussed. Then another sequence with velocity-compensated gradients on all axes
is used to generate phase images in the same FOV as in the first sequence. This last
set of phase maps serves as the reference for flow-compensated images.
The two sets of data are then subtracted from each other to generate a relative phase
map for which each intensity is proportional to the velocity of the spins in that voxel.
Using the phase/velocity relationship the velocity for each phase in a given voxel can
be determined

26. https://youtu.be/oybNRky95iE
https://youtu.be/NKTVKRMfONU

28. MRI

29. FMRI
Functional magnetic resonance imaging (fMRI) measures the small changes in blood flow that
occur with brain activity. It may be used to examine which parts of the brain are handling critical
functions, evaluate the effects of stroke or other disease, or to guide brain treatment.
● Determine which part of the brain is handling critical functions such as thought, speech,
movement and sensation, which is called brain mapping. Studying which parts of the brain
are involved in certain functions of our body is called functional anatomy.
● Help assess the effects of stroke, trauma, or degenerative disease (such as Alzheimer's) on
brain function.
● Monitor the growth and function of brain tumors.
● Guide the planning of surgery, radiation therapy, or other invasive treatments for the brain.

36. FMRI DATA ACQUSITION

37. DWI
Diffusion-weighted imaging (DWI) is a form of MR imaging based upon measuring the random Brownian
motion of water molecules within a voxel of tissue

40. https://www.youtube.com/watch?v=J_aamnpRJE8