**RADIOLOGY for the SHOULDER**

"Treat the patient, not the x-ray"

[PLAIN FILMS :]{.underline}

-   Can show fractures, calcification patterns, and periosteal reactions

-   Remember the "30% rule"

    -   30% of bone must be lost before it is evident on plain films

    -   So NOT sensitive to early changes in bone ^11^

-   **A-P views** (central beam directed toward humeral head, in supine
    or standing)

    -   [External rotation]{.underline}:

        -   Shows anterior aspect of humeral head

            -   Trough line from posterior dislocation

        -   shows **Greater Tuberosity** in profile at lateral aspect

        -   with Lesser Tuberosity superimposed behind humeral head

    -   [Internal rotation]{.underline}:

        -   shows **Lesser Tuberosity** in profile at medial aspect

        -   shows posterior aspect of humeral head

            -   Hill-Sachs (hatchet) lesions

        -   Greater Tuberosity not visible

    -   [Grashey projection/ posterior oblique view]{.underline}
        (rotated 40 degrees toward side)

        -   shows G-H joint space

        -   and glenoid in profile to demonstrate posterior dislocation

    -   [A-C joint]{.underline} (beam directed 15 degrees cephalad
        toward clavicle

        -   Stress views (weights strapped to patient's forearms to
            demonstrate subluxation)

        -   Grading of separations ^11^

            -   Grade I: mild sprain

                -   Minimal widening of AC joint space

                    -   Normal = 0.3 -- 0.8 cm

            -   Grade II : moderate sprain

                -   Widening to 1.0 -- 1.5 cm (25 -- 50 %)

            -   Grade III: severe sprain

                -   Widening \>1.5 cm (\>50%)

-   **Transscapular ("Y") view** (patient standing, facing film, turned
    20 degrees toward opposite side, shoulder slightly abducted so that
    dorsal hand rests on ipsilateral hip) (beam directed toward medial
    border of scapula)

    -   shows true lateral view of scapula

    -   and oblique view of humerus

    -   shows dislocations and fractures (coracoid, acromion, body of
        scapula, and proximal humerus)

-   **Outlet view** (similar to Transscapular (Y) view but beam directed
    toward superior aspect of humeral head angled about 10-15 degrees
    caudad)

    -   shows fractures of acromion

    -   and morphologic type of the acromion.

-   **Axillary view** (seated with shoulder abducted over film) shows
    G-H joint from superiorly (beam directed superior-medial to
    inferior-lateral 5-10 degrees)

    -   Shows fractures of proximal humerus and coracoid process

    -   shows relationship of humeral head to glenoid

        -   shows anterior or posterior dislocations

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    -   **[Lawrence variant]{.underline}** (supine with shoulder
        abducted...does NOT require full abduction) (beam directed
        horizontally slightly superior to mid-portion of axilla; less
        abduction requires increased medial angulation).

-   **West Point view** (prone with shoulder abducted) (beam directed
    inferior-lateral to superior-medial at 25 degrees from patient's
    midline, and posterior-inferior to superior-anterior at 25 degrees
    from table surface; film at superior aspect of shoulder)

    -   Similar to axillary view

        -   But shows BEST view of anterior-inferior rim of glenoid

            -   better than Axillary view.

-   **Transthoracic Lateral view** (beam directed below axilla, slightly
    above nipple line)

    -   shows true lateral view of proximal humerus

        -   shows relationship of humeral head to glenoid

    -   demonstrates displacement or angulation of bony fragments

-   **Bicipital groove Tangent view** (standing, leans over table
    resting on dorsum of forearms with film held on volar forearm)

    -   Show tangent view of bicipital groove

-   **Others**

    -   Stryker Notch view

        -   Supine with film behind shoulder with palm behind head

        -   Beam directed over coracoid process with 10 degree cephalad
            tilt

    -   Hill-Sachs view

        -   A-P view with humerus in extreme IR

[SCINTIGRAPHY (Radionuclide Bone Scan)]{.underline}

-   IV injection with radiopharmaceutical substance

-   Scanned hours after injection

-   Uptake and detection of areas of reactive bone

-   Not specific or diagnostic because many conditions can have same
    appearance

    -   But can show distribution of lesions

-   Can show Osteoclastic / osteoblastic changes in bone

-   Fractures( including stress fractures)

-   Infections

-   Tumors

    -   **Osteod Osteoma** (primary benign) is the [only
        diagnosis]{.underline} with a characteristic presentation (?) on
        bone scan

[ARTHROGRAM]{.underline}:

-   uses contrast agent injected into joint capsule with standard A-P
    views (neutral, ER, IR) and Axillary views

    -   used to identify RCTs (partial/complete)

    -   shows Axillary pouch, subscapularis recess, and bicipital tendon
        sheath

-   single-contrast technique used since 1930s ^2^

    -   double-contrast (includes injection of 10-15 ml of room air)
        developed in the 1970s

-   lack sensitivity ^2^

    -   relies on passage of contrast material out of joint space

        -   difficulty depicting more superficial and bursal aspects of
            RTC

        -   may not show partial-thickness tears

> **CT Arthrogram**

-   Few studies have directly compared MRA to CT-A, but results suggest
    that, with the exception of bony changes, CT-A is less sensitive ^1^

-   *CT-A using new multidetector techniques has not been fully
    evaluated in the shoulder* ^1^

    -   *Early results indicate that its capability to use isotropic
        data acquisition may make it perform equivalent to MR-A* ^1^

[MRI:]{.underline}

-   T1-weighted images show better anatomical detain than T2-weighted
    images

    -   **Chronic tendonitis** may show increased signal in T1-weighted
        images, but not on T2-weighted images ^2^

-   T2-weighted images are better for acute trauma

    -   Fluids (edema) are shown bright

    -   Can use [Fat suppression]{.underline} for contrast between fat
        and fluids

        -   Fat suppression increases accuracy ^2^

-   Hyaline cartilage pathology:

    -   In order of purported accuracy ^9^ :

        -   3 dimensional spoiled gradient echo with fat suppression

        -   T2-weighted fast spin echo with fat suppression

        -   STIR

        -   Gradient echo

        -   Conventional spin echo

-   Low field ("open") MRI ^6^ :

    -   Allows imaging of shoulder, knee, or hip during full range of
        motion

    -   Provides access to patients during scanning and therefore
        permits interventional procedures, including aspiration
        cytology/biopsy and different drainage procedures, which can be
        monitored by MRI.

        -   Can be percutaneous or open surgical procedure ^7^

        -   Low field scanners usually operate around 0.2 T ^7^

-   **MR Arthrography (MRA):**

    -   Superior to conventional MR in diagnosis of labor-ligamentous
        injuries, intrinsic impingement, SLAP lesions and rotator cuff
        pathology ^1^

        -   Advantage over conventional MR due to capsular distension
            with separation of anatomic structures to allow more
            confident distinction of pathology from common anatomic
            variation of labral morphology and from congenital
            variations of glenohumeral ligaments and the
            labor-ligamentous unit (such as the Buford complex). May not
            be necessary in examinations following acute shoulder
            dislocation because joint effusion and hemorrhage serve as
            "natural" contrast media

    -   Preoperative imaging of choice for many sports medicine surgeons
        ^9^

        -   Rotator cuff and labral abnormalities often (35% ^10^ )
            coexist

    -   Standard of imaging for the shoulder (Beltran 1997) ^11^

    -   Uses fluoroscopy (iodinated to verify position)to guide puncture
        of joint capsule to administer contrast media (Gadolinium;
        ringer solution)

    -   Includes T1-weighted spin echo (SE) sequences ^1^:

        -   Transverse

        -   Coronal oblique plane

            -   Fat-suppression routinely used in this plane

            -   May be supplemented by Intermediate weighted (echo time
                = 33 -- 45 ms) turbo spin-echo (TSE) with spectral
                fat-suppression

        -   Sagittal oblique

        -   *Geometric parameters are identical for all sequences with a
            section thickness of 3mm and an in-plane resolution of 0.4 x
            0.3-0.5mm*

    -   For [Anterior instability]{.underline} or suspected
        [Posterosuperior glenoid impingement]{.underline} may add ^1^:

        -   T1-weighted SE and/or and Intermediate weighted TSE sequence
            in the ABER (abduction and externally rotated) position

            -   Although this position can sometimes reduce displacement
                and thus identification difficult in some cases