Which Shoulder MRI, X-ray, and CT Files Actually Open Here

The shoulder studies people actually bring in

Shoulder MRI is planned around the rotator cuff, not the whole joint at once. Expect an oblique coronal series aligned to the supraspinatus tendon, an oblique sagittal series through the cuff outlet used to grade fatty infiltration on the Goutallier scale, and an axial series that runs through the glenoid and biceps tunnel. When a labral tear is suspected, the radiologist adds gadolinium into the joint first — an MR arthrogram — and often positions the arm in abduction and external rotation, the ABER view, to unfold the anteroinferior labrum.

Plain film shoulder series follow a different logic: a true AP taken at an angle to the scapula (the Grashey view) so the joint space opens up, a scapular Y view to check whether the humeral head sits centered under the acromion, and an axillary view that is the only projection showing anterior versus posterior dislocation. Pre-surgical shoulder CT adds a third pattern again — thin axial slices reconstructed into a 3D glenoid model so a surgeon can measure bone loss before a stabilization or Latarjet procedure.

How a shoulder exam is usually packaged for you

Because the arthrogram injection and the MRI are performed as two separate encounters, you will often receive two accession folders on the same disc — one holding the fluoroscopic needle-placement images, the other the actual MRI series. Hospital CDs usually wrap all of it in a DICOMDIR index; patient-portal downloads tend to arrive as a flat ZIP with every series folder at the top level. Either shape works here.

Inside a multi-series folder, the oblique coronal proton-density fat-saturated stack is usually the one radiologists and patients care about most for cuff tears, so look for it by series description if you only want to review one thing quickly. If your imaging passed through a university research pipeline, you may instead have NIfTI exports — those load the same way as the archives below.

Archive formats

If your scan came as one big compressed file, drop it directly into the viewer — we unpack it in your browser.

• ZIP — the most common format on hospital CDs and patient-portal downloads
• TAR — common for research datasets
• .tar.gz and .tgz — TAR + GZIP compressed

DICOM transfer syntaxes

The technical format used to encode pixel data inside a DICOM file. Our viewer decodes every common transfer syntax used by clinical scanners.

• Implicit VR Little Endian (1.2.840.10008.1.2)
• Explicit VR Little Endian (1.2.840.10008.1.2.1)
• JPEG Lossless (1.2.840.10008.1.2.4.70)
• JPEG Extended 12-bit (used by i-CAT dental CBCT)
• RLE Lossless
• 8-bit, 12-bit, and 16-bit pixel data
• MONOCHROME1 and MONOCHROME2 photometric interpretations

NIfTI (research / converted scans)

NIfTI (Neuroimaging Informatics Technology Initiative) is the format used by most research and post-processing tools. If you ran your scan through a pipeline like FreeSurfer or fastMRI, you likely have a NIfTI file.

• .nii — uncompressed NIfTI volume
• .nii.gz — GZIP-compressed NIfTI (most common)

Slice spacing and why shoulder 3D behaves differently

Shoulder MRI planes are already tilted to match the cuff anatomy, so a 3–4 mm oblique coronal or oblique sagittal stack reformats poorly into other planes — the angle that makes the images useful for reading a tear is the same angle that breaks a clean cross-reformat. Shoulder CT is the opposite case: it is usually acquired as thin, isotropic axial slices specifically so the 3D glenoid bone-loss model reconstructs smoothly. A single Grashey, scapular Y, or axillary radiograph has no depth information at all — it stays a flat 2D image no matter how it is viewed.

The axial series through the glenoid usually sits closer to isotropic than the oblique stacks, which is why it is the one that tolerates a rough 3D preview even from a standard MRI protocol, while the oblique coronal and oblique sagittal series are best read one slice at a time, exactly as the radiologist intended. If your CT was acquired with wide axial spacing for a quick trauma read rather than a dedicated pre-operative glenoid protocol, expect the same limitation — thin, isotropic slices are what make the 3D bone model worth trusting for a stabilization or Latarjet plan.

Compatibility at a glance

Privacy and viewing a shoulder study in 3D

Nothing about your rotator cuff MRI, arthrogram, or glenoid CT is uploaded to a server — decoding, slice navigation, and any 3D glenoid reconstruction run inside your browser tab and disappear when you close it. That matters for shoulder cases in particular because the arthrogram's fluoroscopic images and the MRI series both carry the visit's identifying header fields, so keeping both local rather than routing them anywhere avoids the extra exposure of shuttling two studies instead of one.

When a shoulder file won't open

The most common shoulder-specific snag is an arthrogram split across two accession folders — if only the fluoroscopic injection images loaded, go back to the disc or portal and look for a second folder holding the MRI series, since the two are almost never combined by the imaging center. Post-operative shoulders with suture anchors, a reverse or anatomic replacement, or a Latarjet screw still open normally; the hardware just produces expected signal dropout or streak artifact rather than a load failure. Beyond that, encrypted CDs from older European PACS systems and vendor-specific proprietary exports outside the supported list remain the exceptions — ask the imaging center for an unencrypted DICOM export, or combine a multi-disc study into one ZIP before dropping it in.