Lower Spine MRI (1) - עותק

LOWER SPINE MRI

גל שי הנדסה רפואית

MRI לדימות ברפואה

THINGS WE’LL TALK ABOUT

Spine Anatomy

Spine Injuries/Diseases

MRI Indications

Lumbar Spine MRI Principles

No More Time…

SPINE ANATOMY

8 Cervical

12 Thoracic

5 Lumbar

Sacrum + Coccyx

SPINE ANATOMY

The aorta and vena cava

Separating around the level of

the L3/L4 disc space

Aorta

Vena cava

Iliac arteries

Iliac veins

Midsacral vessels

SPINE ANATOMY

Lumbar Spine Anatomy

SPINE INJURIES/DISEASES

MRI INDICATIONS

MRI INDICATIONS

MRI פחות

יעיל בדימות

של פגיעות

אנטומיות

RI PRINCIPLES MPINE SUMBAR L

T1- when contrast is dependent on differences

in longitudinal magnetic relaxation times

values between various tissues the image is

called “T1-weighted”.

T2- when contrast is mostly determined by

differences in transverse magnetic relaxation

values the image is called “T2-weighted”.

RI PRINCIPLES MPINE SUMBAR L

T1: T1-weighting is mainly used to produce a

“fat image”.

RI PRINCIPLES MPINE SUMBAR L

T2- bright signal intensity of water (CSF,

nucleus pulposus) is mainly seen in images

with T2-weighting, therefor known as “water

images”.

RI PRINCIPLES MPINE SUMBAR L

FastSpinEcho vs. ConventionalSpinEcho in T2-

• in a CSE sequence epidural fat & bone marrow fat have low

signal intensity, while FSE produces a much higher fat

signal.

• In FSE T2-weighted images epidural and foraminal fat may

be almost in the same intense as CSF.

• FSE T2-W images provide “water contrast” as well as “fat

contrast”.

RI PRINCIPLES MPINE SUMBAR L

Cont.

• Difficult to see degenerative changes/

metastases/ osteomyelitis (bone infection)

symptoms.

• Alternative option for “water image” is to use a

T2* -weighted gradient-echo (GRE) sequence

(but mostly for cervical area).

RI PRINCIPLES MPINE SUMBAR L

How to reduce fat from our picture-

• Short TI inversion recovery (STIR).

• Spectral fat suppression by pre-saturation (SPIR).

RI PRINCIPLES MPINE SUMBAR L

Imaging Planes-

generally, in sectional imaging, anatomic surfaces/

structures are best imaged in a plane which lies

perpendicular to the surface of interest.

• Sagittal: Images in this plane are best for demonstrating

disc herniations, mid-sagittal diameter of the spinal canal,

increase or decrease in sagittal diameter of the spinal

canal.

axial

RI PRINCIPLES MPINE SUMBAR L

• Axial: extent of a disc abnormality, lateral recesses of the spinal

canal are best studied in the axial plane, The foramen and its

contents can be studied in axial images (less well than in the

sagittal plane).

• Coronal: This imaging plane is used only rarely in diagnosis of

degenerative disease. Some spinal deformities such as

scoliosis or hemivertebra are imaged best in the coronal plane.

RI PRINCIPLES MPINE SUMBAR L

Fat areas

Fat, vascular,

infected areas

Liquid areas

Summary

Bye Bye