Revision History


In addition to the exam-specific instructions in the following tables, review the following information prior to examination selection and submission. Failure to follow the guidance below may result in failure of the submitted examination.

  • Direct or indirect MR arthrograms are not acceptable in place of non-contrast enhanced examinations.

  • ALL joint examinations require three imaging planes. Unless otherwise noted, these can be orthogonal to each other or mildly angulated to better demonstrate specific conditions, as long as all pertinent anatomic structures are completely demonstrated.

  • All examinations: Field of view should be limited to the area of interest, but include the anatomical coverage requirements listed for the specific exams. 

  • ALL examinations must include at least one non-fat-suppressed, T1-weighted sequence. This can be acquired as a spin-echo acquisition, or as a fast spin-echo acquisition with scanning parameters (including echo-train length, inter-echo spacing, effective TE, and readout bandwidth) optimized to reduce blurring. Bone marrow, trabeculae, cortex, skeletal muscle, and extra-articular structures bounded by fat should all be sharply defined on the T1-weighted images.

  • ALL examinations should also include at least one fluid-sensitive sequence with suppressed fat signal. These can be can acquired as intermediate-TE or long-TE (or effective-TE) spin-echo or fast spin-echo acquisitions, or as T2*-weighted gradient-recalled acquisitions. Suppression of fat signal may be accomplished with a chemical (spectral) based method, an inversion recovery method (e.g. STIR), a phase-dependent method (e.g. Dixon technique), or selective water excitation. The signal intensity of fluid should be bright and the signal intensity of fat should be darker than fluid (but does not have to be completely saturated and black). Nevertheless, the images should still demonstrate a gray scale that allows visualization of normal anatomic structures.

  • Sequences can be acquired in 2D or 3D mode; however, separate acquisitions are required for each required sequence. Images acquired in one imaging plane and reformatted into another plane CANNOT be used in place of a second acquired sequence.

  • The specified spatial resolutions for each required sequence will be enforced, but should not be interpreted as being, in and of itself, the only criterion for failure. Note that the pixel dimensions and areas must be less than or equal to the value specified. Do NOT use “interpolated” matrix dimensions when determining the pixel dimensions – the number of phase-encoding or frequency-encoding steps actually acquired should be used. Check your calculations carefully.

  • Refer to the individual ACR Practice Parameters for Musculoskeletal MRI examinations for more detailed explanations and justifications for the required examination elements.

  • The spatial resolution pixel area values indicated in the tables below are optimal values. Deviations from these values may be acceptable as long as other image quality parameters are acceptable.

  • Failure to meet anatomic coverage and imaging plane specifications may result in a fail of the submitted examination.



Elbow for Internal Derangement

Required Sequences

Category A: 

Pulse Sequence and Image Contrast

Category B: 

Anatomic Coverage and Imaging Planes

Category C: 

Spatial Resolution

Axial dark fluid or long TR/short TE

  • Trabeculae and cortex must be sharply defined

  • Must have good definition of surrounding tissues

  • Must have good contrast between fat and non-fat tissues

  • Tendons must be well discriminated (biceps and brachialis tendon; common flexor and extensor tendon; triceps tendon)

  • Images must be perpendicular to the long axis of the elbow

  • Must cover the entire soft tissues of the elbow

  • Must cover from above the humeral epicondyles to the entire biceps tendon insertion on the radial tuberosity

  • Must cover the entire biceps tendon insertion on the radial tuberosity

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.2 mm

  • Pixel area ≤ 0.4 mm2

Axial STIR or bright fluid, with or without fat suppression

  • Must have good definition of surrounding tissues

  • Tendons must be well discriminated (biceps and brachialis tendon; common flexor and extensor tendon; triceps tendon)

  • Images must be perpendicular to the long axis of the elbow

  • Must cover the entire soft tissues of the elbow

  • Must cover from above the humeral epicondyles to the entire biceps tendon insertion on the radial tuberosity

  • Must cover the entire biceps tendon insertion on the radial tuberosity

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.2 mm

  • Pixel area ≤ 0.4 mm2

Coronal dark fluid

  • Trabeculae and cortex must be sharply defined

  • Must have good definition of surrounding tissues

  • Must have good contrast between fat and non-fat tissues

  • Must have good cartilage visualization

  • Must have good definition of collateral ligaments

  • Must have good discrimination of common flexor and extensor tendons

  • Images must be parallel to the epicondylar axis as prescribed from the axial image

  • Must cover the entire soft tissues of the elbow

  • Must cover from above the humeral epicondyles to the entire biceps tendon insertion on the radial tuberosity

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.4 mm2

Coronal bright fluid with fat suppression, which includes STIR or frequency-selective fat suppression techniques

  • Must have good definition of surrounding soft tissues

  • Must have good discrimination of:

    • Fluid vs. soft tissue

    • Common flexor and extensor tendon

    • Cartilage vs. joint fluid

  • Must have good definition of collateral ligaments

  • Images must be parallel to the epicondylar axis as prescribed from the axial image

  • Must cover the entire soft tissues of the elbow

  • Must cover from above the humeral epicondyles to the entire biceps tendon insertion on the radial tuberosity

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.4 mm2

Sagittal bright fluid

  • Trabeculae and cortex must be sharply defined

  • Must have good definition of surrounding tissues

  • Must have good discrimination of triceps tendon, biceps tendon, and cartilage from joint fluid

  • Images must be perpendicular to the epicondylar axis as prescribed from the axial image

  • Must cover the entire soft tissues of the elbow

  • Must cover from above the humeral epicondyles to the entire biceps tendon insertion on the radial tuberosity

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.4 mm2



Forefoot

Required Sequences

Category A: 

Pulse Sequence and Image Contrast

Category B: 

Anatomic Coverage and Imaging Planes

Category C: 

Spatial Resolution

Short axis dark fluid (perpendicular to the metatarsals)

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good contrast between fat and non-fat tissues

  • Must have good discrimination of tendons

  • Must visualize metatarsophalangeal joint capsule

  • Must have good visualization of plantar plate

  • Must include proximal interphalangeal joint (PIP)

  • Must include at least the distal half of all metatarsals

  • Must align perpendicular to the long axis of the metatarsals

  • Must cover entire soft tissues of the forefoot

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.3 mm 

  • Pixel area ≤ 0.4 mm2

Short axis (perpendicular to the metatarsals) bright fluid with fat suppression which includes STIR or frequency selective fat suppression techniques

  • Must have good definition of surrounding soft tissues

  • Must have good contrast between tissue and fluid

  • Must have good discrimination of tendons

  • Must visualize metatarsophalangeal joint capsule

  • Must have good visualization of plantar plate

  • Must include proximal interphalangeal joint (PIP)Must include at least the distal half of all metatarsals

  • Must align perpendicular to the long axis of the metatarsals

  • Must cover entire soft tissues of the forefoot

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.3 mm

  • Pixel area ≤ 0.4 mm2

Long axis (parallel to the metatarsals and plantar surface) bright fluid with fat suppression which includes STIR or frequency selective fat suppression techniques

  • Must have good definition of surrounding soft tissues

  • Must have good contrast between tissue and fluid

  • Must have good discrimination of tendons

  • Must visualize metatarsophalangeal joint capsule

  • Must include tips of toes

  • Must include at least the distal half of all metatarsals

  • Must align parallel to the long axis of the metatarsals

  • Must cover entire soft tissues of the forefoot

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.3 mm

  • Pixel area ≤ 0.4 mm2

Sagittal (parallel to the metatarsals)

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good discrimination of tendons

  • Must include tips of toes

  • Must include at least the distal half of all metatarsals

  • Must align perpendicular to the long axis sequence and parallel to the long axis of the metatarsals

  • Must cover entire soft tissues of the forefoot

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.3 mm

  • Pixel area ≤ 0.4 mm2



Shoulder for Internal Derangement

Required Sequences

Category A: 

Pulse Sequence and Image Contrast

Category B: 

Anatomic Coverage and Imaging Planes

Category C: 

Spatial Resolution

Coronal oblique, sagittal or axial dark fluid

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good definition of labrum

  • Must have good definition of tendons (supraspinatus, infraspinatus and subscapularis)

  • Must be parallel to supraspinatus tendon as seen on axial cut through the superior portion of the shoulder or perpendicular to the articular surface of the glenoid fossa as seen on axial images 

  • Must include the teres minor muscle posterior to the humeral head through the anterior coracoid tip

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 0.8 mm

  • Pixel area ≤ 0.8 mm2

Axial long TR/short TE

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good definition of labrum

  • Must have good definition of biceps in bicipital groove

  • Must cover from the top of the acromion to the bottom of the glenohumeral joint using the coronal scout image as a localizer

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 0.8 mm 

  • Pixel area ≤ 0.8 mm2

Coronal bright fluid with fat suppression which includes STIR or frequency selective fat suppression techniques

  • Must have homogeneous fat saturation

  • Must have good definition of surrounding soft tissues

  • Must have good definition of labrum

  • Must have good definition of tendons (supraspinatus, infraspinatus and subscapularis)

  • Must be parallel to supraspinatus tendon as seen on axial cut through the superior portion of the shoulder or perpendicular to the articular surface of the glenoid fossa as seen on axial images

  • Must include the teres minor muscle posterior to the humeral head through the anterior coracoid tip

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 0.8 mm

  • Pixel area ≤ 0.8 mm2

Sagittal oblique bright fluid

  • Must have good definition of surrounding soft tissues

  • Must have good definition of rotator interval

  • Must have good definition of tendons (supraspinatus, infraspinatus, subscapularis, teres minor, biceps)

  • Must be parallel to the articular surface of the glenoid fossa as seen on axial images

  • Must cover the scapular neck through the lateral margin of the humerus

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 0.8 mm

  • Pixel area ≤ 0.8 mm2



Wrist for Internal Derangement

Required Sequences

Category A: 

Pulse Sequence and Image Contrast

Category B: 

Anatomic Coverage and Imaging Planes

Category C: 

Spatial Resolution

Coronal oblique dark fluid

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good definition of scapholunate ligament and triangular fibrocartilage complex

  • Must have dark fluid and bright fat

  • Fluid must be dark and fat must be bright (i.e. T1-weighted)

  • Must cover entire wrist including extrinsic ligaments and tendons

  • Must cover from Lister’s tubercle through the bases of the metacarpals

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.5 mm 

  • Pixel area ≤ 0.3 mm2

Coronal oblique bright fluid

  • Must have bright fluid

  • Must have good definition of surrounding soft tissues

  • Must have good definition of tendons (scapholunate ligament and triangular fibrocartilage complex)

  • Must cover entire wrist including extrinsic ligaments and tendons

  • Must cover from Lister’s tubercle through the bases of the metacarpals

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.5 mm

  • Pixel area ≤ 0.3 mm2

Axial dark fluid or long TR/short TE

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must have good definition of individual extensor tendons

  • Must cover entire soft tissues anterior through posterior

  • Must cover distal radioulnar joint through the bases of the metacarpals

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.6 mm

  • Pixel area ≤ 0.3 mm2

Axial bright fluid

  • Fluid must be bright

  • Must have good definition of surrounding soft tissues

  • Must have good definition of individual extensor tendons

  • Must cover entire soft tissues anterior through posterior

  • Must cover distal radioulnar joint through the bases of the metacarpals

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.6 mm

  • Pixel area ≤ 0.3 mm2

Sagittal

  • Must have good definition of trabeculae and cortex

  • Must have good definition of surrounding soft tissues

  • Must cover entire soft tissues anterior through posterior

  • Must cover distal radioulnar joint through the bases of the metacarpals

  • Slice thickness ≤ 3.0 mm

  • Gap ≤ 0.6 mm

  • Pixel area ≤ 0.3 mm2



KNEE such as for Internal Derangement



Must have fat suppression on at least one sagittal or coronal sequence.
If all the sagittal requirements listed are met by one sagittal sequence, then an additional sagittal sequence will not be required. 
Please review the requirements carefully for both sagittal sequences.

Required Sequences

Category A: 

Pulse Sequence and Image Contrast

Category B: 

Anatomic Coverage and Imaging Planes

Category C: 

Spatial Resolution

Sagittal PD-weighted: 2D or 3D; SE, FSE, or GRE; with or without fat suppression (for menisci)

  • Must have good definition of menisci

  • Must have good contrast between menisci and articular cartilage

  • Must have good contrast between menisci and joint fluid

  • Must cover entire menisci, including any potentially displaced fragments

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.0 mm 

  • Pixel area ≤ 0.6 mm2

Sagittal bright fluid with or without fat suppression (for articular cartilage, ligaments, tendons)

  • Must have good definition of articular cartilage

  • Must have good definition of cruciate ligaments

  • Must have good definition of extensor mechanism

  • Must have bright fluid relative to articular cartilage and fibrocartilage

  • Must include suprapatellar recess, distal quadriceps tendon and tibial tubercle

  • Must cover entirety width of tibia and fibula

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.0 mm 

  • Pixel area ≤ 0.6 mm2

Coronal bright fluid with or without fat suppression which includes STIR or frequency selective fat suppression techniques

  • Must have good definition of menisci, cruciate ligaments and collateral ligaments

  • Must have good contrast between joint fluid and articular cartilage and menisci

  • Must have bright fluid

  • Must include knee from above patella through distal MCL insertion

  • Must cover patella through popliteal vessels

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.6 mm2

Coronal, sagittal or axial dark fluid

  • Must have good definition of trabeculae and cortex

  • Must have good definition of menisci

  • Must have good definition of skeletal muscles, collateral ligaments and other extra-articular structures

  • The dark fluid sequence must be T1-weighted with short TR/short TE, dark fluid and bright fat (NOT a long TR/short TE sequence, which is an intermediate or proton-density weighted sequence)

  • Must include knee from above patella through distal MCL insertion

  • Must cover patella through popliteal vessels

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.6 mm2

Transverse bright fluid with or without fat suppression

  • Must have good definition of cruciate ligaments and collateral ligaments

  • Must have good contrast between joint fluid and articular cartilage

  • Must have bright fluid

  • Must include all anterior, posterior, medial and lateral soft tissues

  • Must cover entire patella and tibial tubercle

  • Slice thickness ≤ 4.0 mm

  • Gap ≤ 1.0 mm

  • Pixel area ≤ 0.6 mm2






Revision History for this Article

Date

Section

Description of Revision(s)

12-12-19

All

Article created; FAQs incorporated; No criteria changes

10-18-2021KneeUpdated Category A for the coronal, sagittal or axial dark fluid sequence
5-10-2022BeginningAdded 3rd bullet regarding FOV




Previous: Exam-Specific Parameters: Spine
Next: Exam-Specific Parameters: Body