CT OF THE ANKLE: WHAT YOU AND YOUR SURGEON WANT TO SEE

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Colleen Mitchell
5 years ago
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1 CT OF THE ANKLE: WHAT YOU AND YOUR SURGEON WANT TO SEE Associate Professor, Department of Radiology, Musculoskeletal Section 600 Highland Ave, E3/311 Madison, WI (office) (e-fax) ( ) (URL) ble of Contents for Dr. Schreibman s Handout: page 1...This Cover Page page 2...Modality Flow Chart pages Ankle CT Anatomy pages My CT Protocol (You might want to share the Anatomy and Protocol pages with your CT technologists) If the figures in this handout do not photocopy clearly, you can download your own original version via the above website. Or you can send me an and I ll you the Microsoft Word document containing the original images.

2 Ken L Schreibman, PhD/MD 2003 page 2 of 7 v2c 3/1/03

3 Ankle CT Anatomy Axial: above syndesmosis Axial: through syndesmosis Axial: through ankle joint Fi Ti Fi Ti LM LM MM Ti=Tibia Arrow points to syndesmosis =lus Fi=Fibula LM,MM=Lat/Med Malleolus Axial: top of calcaneus Axial: middle of calcaneus Axial: bottom of calcaneus N 3 Cu 2 N 1 II III 3 Cu I 1 N=Navicular 1,2,3=Cuneiforms I,II,III=Metatarsals =lcaneus Cu=Cuboid Ken L Schreibman, PhD/MD 2003 page 3 of 7 v2c 3/1/03

AJ LPT Cu CCJ Ti P-STJ Sagittal reconstruction: lateral ankle Ti=Tibia

P-ST=Posterior facet Sub-lar Joint LPT=Lateral Process of the lus

Sub-lar Joint TNJ=lar-Navicular Joint M-STJ Sagittal reconstruction:

4 AJ LPT Cu CCJ Ti P-STJ Sagittal reconstruction: lateral ankle Ti=Tibia =lus =lcaneus Cu=Cuboid AJ=Ankle Joint CCJ=lcaneal-Cuboid Joint P-ST=Posterior facet Sub-lar Joint LPT=Lateral Process of the lus Sagittal reconstruction: middle ankle TNJ P-STJ M-STJ=Middle facet Sub-lar Joint TNJ=lar-Navicular Joint M-STJ Sagittal reconstruction: medial ankle Q ST=Sustentaculum li M-STJ * ST Ken L Schreibman, PhD/MD 2003 page 4 of 7 v2c 3/1/03

5 Plane and range of coverage for Coronal Oblique images, perpendicular to the Sub-lar Joint Coronal Oblique: through Ankle Joint and back of the Sub-lar Joint. Coronal Oblique: through Sustentaculum li (*) Coronal Oblique: through sinus tarsi Coronal Oblique: lar-navicular Joint Ken L Schreibman, PhD/MD 2003 page 5 of 7 v2c 3/1/03

UW Ankle/Foot CT Protocol SCANNING PARAMETERS Overview Our goal is to have one single scanning protocol for all ankles and feet.

ÿ Images are then reconstructed in planes specified for each patient. In most cases it is desirable to scan both ankles/feet at the same time.

ÿ The accompanying reconstruction protocol sheet will specify which ankle to film. Positioning Patient Supine. Toes pointing up. ÿ Feet as close together as possible. ÿ pe feet together.

6 UW Ankle/Foot CT Protocol SCANNING PARAMETERS Overview Our goal is to have one single scanning protocol for all ankles and feet. ÿ This will help to maintain uniformly high-quality imaging for all of our patients. Our technique uses thin helical slices to obtain a solid volume of imaging data. ÿ Images are then reconstructed in planes specified for each patient. In most cases it is desirable to scan both ankles/feet at the same time. ÿ This is more comfortable for the patient rather than bending one leg out of the way. ÿ This does not interfere with imaging the side in question, and permits comparison with the contralateral side. ÿ The accompanying reconstruction protocol sheet will specify which ankle to film. Positioning Patient Supine. Toes pointing up. ÿ Feet as close together as possible. ÿ pe feet together. ÿ Consider taping feet to a box, with the soles of the feet flat against the box. This helps achieve uniform positioning. Plaster casts/splints are not a problem. Indeed, helps assure the patient doesn t move. Both ankle/feet should be centered in the scanner. ÿ If it is not physically possible to bring the feet together, center the side in question. Helical Technique All CTs should be performed on scanners 2 or 4 (unless specified otherwise). Scan using the following parameters ÿ 0.6mm thick helical slices Coverage (AP scout) Coverage ÿ Small Scanning Field of View. (Lat. scout) Higher for ÿ 22cm Display Field of View. Pilon Fx ÿ 200 ma. ÿ Do not angle the gantry. ÿ BonePlus & Standard algorithms. Coverage From above syndesmosis ÿ Higher for pilon fractures. Ortho will specify how high above ankle joint. To below calcaneus Filming Do not film any of the original 0.6mm images. Film the appropriate reconstruction images. ÿ 12-on-1 (23 reconstruction images, plus the localizer, will fill two sheets of film.) ÿ Annotate Right or Left Make sure that ALL of the reconstruction images, as well as ALL of the original images, are sent to the ALI PACS. Make sure the requisition, along with protocol sheet and any other paperwork, is delivered to the bone reading area and placed in the hanging clear plastic box labeled CT TO BE READ. Ken L Schreibman, PhD/MD 2003 page 6 of 7 v2c 3/1/03

UW Ankle/Foot CT Protocol RECONSTRUCTION PARAMETERS This form may be sent to the CT Scheduling Desk via Fax (262-4513) or Tube Station # 431 Protocoled by: cblankenbaker cchoi cdavis cdesmet

Side cright Only cleft Only cr&l Together cr&l Individually (billed as 2 studies) Area of Clinical Concern Reconstruction Planes clcaneus, Hindfoot, Sub-lar Joint, rsal Coalition, lus Fx.

7 UW Ankle/Foot CT Protocol RECONSTRUCTION PARAMETERS This form may be sent to the CT Scheduling Desk via Fax ( ) or Tube Station # 431 Protocoled by: cblankenbaker cchoi cdavis cdesmet cschreibman ctuite cfellow crichard Lange cother (specify) cradiologist must check study before patient gets off the table. cpatient being seen right after scan send films with patient. Side cright Only cleft Only cr&l Together cr&l Individually (billed as 2 studies) Area of Clinical Concern Reconstruction Planes clcaneus, Hindfoot, Sub-lar Joint, rsal Coalition, lus Fx...(A)(B)(D) cankle Joint, OCD... (A)(B)(E) cmidfoot, Forefoot, Lisfranc...(A)(B) cnavicular...(a)(b)(c) cpilon Fx (specify how high above ankle joint) (A)(B)(E) cother (specify) USE BONE-PLUS DATA. RECONSTRUCT 3mm THICK AT 3mm SPACING (A) SAGITTAL Set-up off of Axial (B) OBLIQUE AXIAL Set-up off Sagittal. Parallel to Metatarsal (D) OBLIQUE CORONAL (C) NAVICULAR Perpendicular to (B) Set-up off of Axial. Parallel to line along fronts of Malleoli MM Set-up off Sagittal. Perpendicular to Sublar Joint LM (E) MORTISE CORONAL Ken L Schreibman, PhD/MD 2003 page 7 of 7 v2c 3/1/03

PROPHECY. Preoperative Navigation Guides ANKLE CT SCAN PROTOCOL

PROPHECY. Preoperative Navigation Guides ANKLE CT SCAN PROTOCOL PROPHECY Preoperative Navigation Guides ANKLE CT SCAN PROTOCOL 90 FIGURE 1 Examples FIGURE 1 Examples of neutral ankle positioning. PROPHECY Ankle CT Scan Protocol PROPHECY INBONE and PROPHECY INFINITY