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Psoas Muscle MRI Protocols and planning

Indications of psoas muscle MRI scan

Psoas muscle Anatomy

The psoas muscle, also known as the iliopsoas, is a large and powerful muscle located deep within the abdomen and pelvis. It is actually made up of two muscles: the psoas major and the iliacus, which work together as a single functional unit. The psoas muscle plays a crucial role in hip flexion, stability of the lumbar spine, and overall posture.

Anatomy:

  1. Psoas Major: The psoas major originates from the lumbar vertebrae (specifically T12 to L5) of the lower spine. It travels downward and laterally, passing through the pelvic region, and inserts onto the lesser trochanter of the femur, which is a bony prominence on the inner side of the thigh bone (femur).

  2. Iliacus: The iliacus muscle arises from the iliac fossa, which is part of the iliac bone of the pelvis. It also travels downward and laterally to join the psoas major at the same insertion point on the lesser trochanter of the femur.

Function: The primary function of the psoas muscle is hip flexion, which involves bringing the thigh towards the abdomen. This action is crucial for activities like walking, running, climbing stairs, and lifting the legs while lying down. Additionally, the psoas muscle helps stabilize the lumbar spine during these movements, providing support and preventing excessive arching of the lower back.

The psoas muscle is often involved in activities that require core stabilization, such as maintaining balance and performing various movements that engage the abdominal muscles. Because of its deep location within the body, the psoas muscle is considered a key player in maintaining proper posture and stability during both static and dynamic activities.

Clinical Significance: Due to its deep location and close proximity to vital structures, the psoas muscle can be a source of pain and discomfort. Psoas muscle strain or irritation can occur due to overuse, improper technique during physical activities, or prolonged sitting. When inflamed or irritated, the psoas muscle can cause pain in the lower back, groin, and hip regions.

Psoas muscle 3d image

psoas muscle 3d image

psoas muscle mri image

T2-weighted turbo spin-echo coronal image of psoas

Contraindications

Patient preparation for psoas muscle MRI

Positioning for psoas muscle MRI

MRI urography positioning photo

Recommended Psoas Muscle MRI Protocols and Planning

Psoas muscle MRI localiser

A three-plane localizer must be taken at the beginning to localize and plan the sequences. Localizers are normally less than 25 seconds and are T1\T2-weighted low-resolution scans.

T2 stir coronal 4mm large FOV

Plan the coronal slices on the sagittal plane; angle the positioning block parallel to the psoas. Check the positioning block in the other two planes. An appropriate angle must be given in the axial plane (across the right and left psoas). Slices must be sufficient to cover the whole psoas from anterior to posterior. The FOV must be big enough to cover the whole psoas (normally 400mm-450mm) from T12 down to the lesser trochanter of the femur. Adding saturation bands in front of the coronal block will reduce artifacts from arterial pulsation and breathing.

Parameters

TR

4000-5000

TE

110

FLIP

150

NEX

2

SLICE

4 MM

MATRIX

384X384

FOV

400-450

PHASE

R>L

GAP

10%

TI

160

T1 tse coronal 4mm large FOV

Plan the coronal slices on the sagittal plane; angle the positioning block parallel to the psoas. Check the positioning block in the other two planes. An appropriate angle must be given in the axial plane (across the right and left psoas). Slices must be sufficient to cover the whole psoas from anterior to posterior. The FOV must be big enough to cover the whole psoas (normally 400mm-450mm) from T12 down to the lesser trochanter of the femur. Adding saturation bands in front of the coronal block will reduce artifacts from arterial pulsation and breathing.

Parameters

TR

400-600

TE

15-25

SLICE

4 MM

FLIP

160

PHASE

R>L

MATRIX

448X384

FOV

400-450

GAP

10%

NEX(AVRAGE)

2

T2 tse (or stir) axial 4 mm 300 fov

Plan the axial slices on the sagittal plane; angle the positioning block perpendicular to the psoas. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the lumbar spine). Slices must be sufficient to cover the whole psoas from T12 down to the lesser trochanter of the femur. FOV must be big enough to cover the whole psoas (normally 300mm). Adding saturation bands in front of the axial block will reduce artifacts from arterial pulsation and breathing.

Parameters

TR

4000-5000

TE

100-120

SLICE

4 MM

FLIP

130-150

PHASE

A>P

MATRIX

320X256

FOV

300

GAP

10%

NEX(AVRAGE)

2

T1 tse axial 4 mm 300 fov

Plan the axial slices on the sagittal plane; angle the positioning block perpendicular to the psoas. Check the positioning block in the other two planes. An appropriate angle must be given in the coronal plane (perpendicular to the lumbar spine). Slices must be sufficient to cover the whole psoas from T12 down to the lesser trochanter of the femur. FOV must be big enough to cover the whole psoas (normally 300mm). Adding saturation bands in front of the axial block will reduce artifacts from arterial pulsation and breathing.

Parameters

TR

400-600

TE

15-25

SLICE

4 MM

FLIP

150

PHASE

A>P

MATRIX

320X320

FOV

300

GAP

10%

NEX(AVRAGE)

2

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