CLINICAL USE AND APPERANCE OF PULSE SEQUENCES ARE DESCRIBED IN DETAILIN THIS PPT. CONTENT TAKEN FROM MUTIPLE BOOKS AND GENERALS.

1. CLINICAL USE AND
APPEARANCE OF PULSE
SEQUENCES
MR. ROHIT BANSAL
ASSISTANT PROFESOR (RADIO-PHYSICS)
MAMC,AGROHA

2. Short repetition timesTR (300-600ms)
Short echo timeTE (10-15ms)
MRI image appearance
The easiest way to identify T1 weighted images is to look for fluid filled
spaces in the body (e.g., Cerebrospinal fluid in the brain ventricles and
spinal canal, free fluid in the abdomen, fluid in the gall bladder and
common bile duct, synovial fluid in joints, fluid in the urinary tract and
urinary bladder, oedema or any other pathological fluid collection in
the body). Fluids normally appear dark in aT1 weighted image.
Pathological appearance
Pathological processes normally increase the water content in tissues.
Due to the added water component this results in a signal loss on T1
weighted images and signal increase on T2 weighted images.
Consequently, pathological processes are usually bright on T2
weighted images and dark onT1 weighted images.
T1 SE/T1 TSE

3. Tissues and theirT1 appearance
Bone marrow: - equal to or higher than that of muscle (fatty marrow
is usually bright)
Muscles- Gray
Moving blood: - Dark
White matter: -Whiter
Gray matter: - Gray
Fluids - Dark
Bone: - Dark
Fat: - Bright
Air: - Dark

4. Use
Useful for pelvic imaging (only used for pelvic infections pre
contrast pelvisT1 imaging)
Useful for abdominal imaging (T1TSE respiratory gated scans)
Useful for chest imaging (T1TSE respiratory gated scans)
Very useful for brachial and lumbar plexus imaging
Very useful for anterior neck, orbits and face imaging
Very useful for any musculoskeletal imaging
Very useful for extremity imaging
Very useful for brain imaging
Very useful for spine imaging

7. MRI image appearance
The easiest way to identify T1 weighted post gadolinium images is to look
for blood vessels in the body (e.g., arteries and veins in the brain, neck,
chest, abdomen, upper limbs and lower limbs). Blood vessels and
pathologies with high vascularity appear bright on T1 weighted post
gadolinium images.
Pathological appearance
Pathologies with hypervascularization will appear bright on T1 weighted
post gadolinium images (e.g., tumours like haemangioma,
Lymphangioma, haemangioendothelioma, Kaposi sarcoma,
angiosarcoma, hemangioblastoma etc. and inflammatory processes like
discitis, meningitis, synovitis, arthritis, osteomyelitis etc.). Pathological
processes with no vascularity will remain unenhanced (appear as dark on
aT1 weighted post gadolinium image).
T1 SE/ T1 TSE/ T1 FSE POST CONTRAST

8. Tissues and theirT1 post gadolinium appearance
Bone marrow: - equal to or higher than that of muscle (fatty
marrow is usually bright)
Muscles- gray
Moving blood: - bright
White matter - whiter
Gray matter gray
Fluids: - dark
Bone: - dark
Fat: - bright
Air: - dark

9. Use
Very useful for brain and IAMs imaging
Very useful for spine imaging
Useful for pelvic imaging
Useful for brachial and lumbar plexus imaging
Useful for anterior neck orbits and face imaging
Useful for any musculoskeletal imaging
Useful for extremity imaging
* Most of the post contrast examinations use fat saturated
post contrast T1 sequences except brain imaging. *

11. TR (2000-6000ms)
TE (100-150ms)
MRI image appearance
The easiest way to identify T2 weighted images is to look for fluid filled spaces
in the body (e.g., Cerebrospinal fluid in the brain ventricles and spinal canal,
free fluid in the abdomen, fluid in the gall bladder and common bile duct,
synovial fluid in joints, fluid in the urinary tract and urinary bladder, oedema or
any other pathological fluid collection in the body). Fluids normally appear
bright onT2 weighted images.
Pathological appearance
Pathological processes normally increase the water content in tissues. The
added water component results in a signal loss on T1 weighted images and a
signal increase on T2 weighted images. Consequently, pathological processes
are usually bright onT2 weighted images and dark onT1weighted images.
T2 SE/ T2 TSE/T2 FSE

12. Tissues and theirT2 appearance
Bone marrow: - equal to or higher than that of muscle (fatty
marrow is usually bright) Muscles- gray (darker than the muscle
signal onT1 images)
Fat - bright (darker than the fat signal onT1 images)
White matter - darker than gray
Moving blood- dark
Gray matter – gray
Fluids - bright
Bone - dark
Air - dark

13. Use
Very useful for abdominal imaging (breath hold and respiratory
gated T2 tse scans) Very useful for pelvic imaging (gyne pelvis,
prostate, urinary bladder and rectum) Very useful for chest imaging
(breath holdT2 tse scans)
Can be useful for brachial and lumbar plexus imaging
Useful for anterior neck, orbits and face imaging
Very useful for any musculoskeletal imaging
Very useful for extremity imaging
Very useful for brain imaging
Very useful for spine imaging

15. TR (2000-5000ms) andTE (10-20).
MRI image appearance
The easiest way to identify PD weighted images is to compare the fluid
against the fat signal. Fluids normally appear as greyish white, almost
similar appearance as the fat in the body.
Use
Very useful for brain imaging (because of great White matter gray
matter contrast)
Useful for extremity imaging (e.g., ankle, knee, elbow, shoulder and
hips)
Can be useful in thighs, lower legs, upper arms and forearms imaging
Very useful for temporo-mandibular joint imaging
PROTON DENSITY (PD)

16. Tissues and their PD appearance
Bone marrow: - equal to or higher than that of muscle (fatty marrow
is usually bright)
Fat - bright (slightly darker than the fat signal inT1 images)
Fluids - bright (darker than the fluid signal inT2 images)
White matter - darker than bright gray
Gray matter - bright gray
Moving blood- dark
Muscles-gray
Bone - dark
Air – dark

18. short inversion time (TI) of 130-150 is used for fat suppression.
MRI image appearance
The easiest way to identify STIR images is to look for fat and fluid filled space
in the body (e.g., Cerebrospinal fluid in the brain ventricles and spinal canal,
free fluid in the abdomen, fluid in the gall bladder and common bile duct,
synovial fluid in joints, fluid in the urinary tract and urinary bladder, oedema or
any other pathological fluid collection in the body). Fluids normally appear
bright and fat appear very dark in a STIR image.
Pathological appearance
Pathological processes normally increase the water content in tissues. Due to
the added water component this results in a signal increase on STIR images.
Consequently, pathological processes are usually bright on STIR images.
SHORT TAU INVERSION RECOVERY (STIR)

19. Tissues and their STIR appearance
Muscles: - darker than fat signal
White matter - darker than gray
Bone marrow: - dark
Moving blood- dark
Gray matter – gray
Fluids – very bright
Bone – dark
Fat – dark
Air - dark

20. Use
Very useful for brachial and lumbar plexus imaging
Very useful for anterior neck orbits and face imaging
Very useful for any musculoskeletal imaging
Very useful for extremity imaging
Very useful for spine imaging
Useful for abdominal imaging (respiratory gated STIR)
Useful for chest imaging (respiratory gated STIR)

22. A long inversion time (TI) of 2000-2500 is used for fluid suppression.
MRI image appearance
The easiest way to identify FLAIR images is to look for CSF filled spaces and
lesions or other pathological processes in the brain or spinal cord. Fluids
normally appear dark and lesions or other pathological processes appear
bright on image. Images normally appear as a fluid suppressedT2 image.
Pathological appearance
Pathological processes normally increase the water content in tissues. The
added water component results in a signal increase on FLAIR images.
Consequently, pathological processes are usually bright on FLAIR images.
FLUID ATTENUATED INVERSION RECOVERY
(FLAIR)/LONG TAU INVERSION RECOVERY/TURBO
DARK FLUID

23. Tissues and their FLAIR appearance
Bone marrow: - equal to or higher than that of muscle (fatty marrow is
usually bright)
White matter - darker than gray
Moving blood- dark
Gray matter – gray
Muscles -gray
Fat – bright
Fluids – dark
Bone – dark
Air – dark
Use
Very useful for brain imaging
Useful for spine imaging

25. Use
Very useful for Diffusion-weighted whole-body cancer screening
Very useful for brain imaging
Very useful for cholesteatoma imaging
Very useful for prostate imaging
Very useful for gynecology imaging
Very useful for breast imaging
Useful for anterior neck imaging
Useful for small bowel imaging
Useful liver imaging
Useful for spine imaging
Useful for sacroiliac joint imaging
DIFFUSION WEIGHTING IMAGING (DWI) / EPI DWI