MRI Scanning Technique of Knee

Initially the localizer images in three planes (axial, coronal and sagittal planes) are taken.

 The external rotation of about 10-15 degrees give better imaging of the anterior cruciate ligament. So, patient positioning must be done carefully.

 T2 sagittal images are planned in the localizer. The epicenter of FOV is kept  at the middle of the joint space in sagittal localizer. The mid scan line is kept at the imaginary line joining the mid shaft of the femur and tibia and perpendicular to the tibial plateau in coronal localizer. The scan lines are obtained no more than 10 degrees oblique to a perpendicular line joining the posterior femoral condyles (the bicondylar line). Sagittal images are scanned from the medial to the lateral femoral condyles.

T1 sagittal images are planned by copying the slice lines of T2 sagittal sequence.

T2 STIR sagittal images are also planned by copying the slice lines of T2 sagittal sequence.

T2 coronal images are planned in a prescribed plane with line parallel to femoral condyles. In axial localizer, the scan lines are angled parallel to the posterior femoral condyles and in sagittal localizer, angle perpendicular to the tibial shaft if tibial plateau is hard to access. Cover from the anterior cortex of patella as far back as possible (cover at least one slice posterior to femoral condyles and make sure fibular head is included.). 

T2 coronal STIR images are planned by copying the slice lines of T2 coronal sequence.

PD sagittal STIR images are planned by copying the slice lines of T2 sagittal sequence. This PD sequence is designed to image Anterior Cruciate Ligament (ACL). Slices are angled to optimize the visualization of ACL. The orientation is a sagittal oblique along the orientation of ACL in axial localizer.

For axial scanning, cover from the top of the patella to about the tibial tuberosity, but at least into the tibial plateau. Images are obtained from distal quadriceps tendon through patellar tendon insertion 

T2 Axial sequence is planned such that the mid-scan line passes through the middle of the joint space in both sagittal and coronal localizer. The epicenter of FOV is kept at the middle of the axial localizer.

T1 Axial sequence is planned by copying the scan lines of the T2 Axial sequence.

The routine sequence in MRI Scanning of knee joint are:

T2 Axial

T1 Axial

T2 Sagittal

T2 Sagittal STIR

T2 Coronal STIR

PD Sagittal