Musculoskeletal Procedures: Diagnostic and Therapeutic

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In times of overburdened daily practice, we are all looking for concise, practical books; books that are easy to consult and in which we rapidly find clear answers to specific problems or suddenly arising queries. Musculoskeletal Procedures: Diagnostic and Therapeutic belongs to this category of books. With the valuable collaboration of a select group of young dedicated musculoskeletal radiologists, the editor has revisited all of the chapters of her previous book, Musculoskeletal Imaging: Diagnostic and Therapeutic Procedures, with the fixed purpose of assisting residents in radiology, orthopaedics, and neurosurgery in their diagnostic and therapeutic procedures. In addition, this book offers the general radiologist a gamut of practical step-by-step techniques now...

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  1. LANDES LANDES V ad e me c u m V ad e me c u m BIOSCIENCE BIOSCIENCE Table of contents Musculoskeletal 1 Shoulder Arthrography . 1. Bone Biopsies 3 Procedures: 2 Elbow Arthrography . 1. Percutaneous Treatment 4 of Osteoid Osteoma 3 Wrist Arthrography . 1. Vertebroplasty 5 4 Hip Arthrography . Diagnostic and Therapeutic 1. Ultrasound 6 5 Knee Arthrography . Appendix 6 Ankle Arthrography . 7 MR Arthrography . 8 Myelography . 9 Discography . 1. Percutaneous Blocks 0 1. Epidural Blocks 1 1. Tenography 2 T i i o eo an ws r e o m d c lh n b o s hs s n f e eis f eia adok. It includes subjects generally not covered in other handbook series, especially many technology-driven topics that reflect the increasing influence of technology i ciia mdcn. n lncl eiie The name chosen for this comprehensive medical handbook series is Vademecum, a Latin word that roughly means “to carry along”. In the Middle Ages, traveling clerics carried pocket-sized books, excerpts of the carefully transcribed canons, known as Vademecum. In the 19th century a medical publisher in Germany, Samuel Karger, called a series of portable medical books Vademecum. The Landes Bioscience Vademecum books are intended to be used both in the training of physicians and the care of patients, by medical students, medical house staff and practicing physicians. We hope you will find them a valuable resource. Jacqueline C. Hodge I SBN 1- 57059- 600- X All titles available at www.landesbioscience.com 9 781570 596001
  2. vademecum Musculoskeletal Procedures: Diagnostic and Therapeutic Jacqueline C. Hodge, M.D. Lenox Hill Hospital Department of Diagnostic Radiology New York, New York LANDES BIOSCIENCE GEORGETOWN, TEXAS U.S.A.
  3. VADEMECUM Musculoskeletal Procedures: Diagnostic and Therapeutic LANDES BIOSCIENCE Georgetown, Texas U.S.A. Copyright ©2003 Landes Bioscience All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Printed in the U.S.A. Please address all inquiries to the Publisher: Landes Bioscience, 810 S. Church Street, Georgetown, Texas, U.S.A. 78626 Phone: 512/ 863 7762; FAX: 512/ 863 0081 ISBN: 1-57059-600-X Library of Congress Cataloging-in-Publication Data CIP applied for but not received at time of publication. While the authors, editors, sponsor and publisher believe that drug selection and dosage and the specifications and usage of equipment and devices, as set forth in this book, are in accord with current recommendations and practice at the time of publication, they make no warranty, expressed or implied, with respect to material described in this book. In view of the ongoing research, equipment development, changes in governmental regulations and the rapid accumulation of information relating to the biomedical sciences, the reader is urged to carefully review and evaluate the information provided herein.
  4. Dedication To my mother
  5. Contents Foreword .......................................................................... xi 1. Shoulder Arthrography ..................................................... 1 Wilfred C.G. Peh and Jacqueline C. Hodge Introduction ............................................................................................... 1 Indications .................................................................................................. 1 Contraindications ....................................................................................... 1 Equipment .................................................................................................. 2 Preliminary Radiographs ............................................................................. 2 Technique ................................................................................................... 2 Contrast Agents .......................................................................................... 4 Post-Puncture Protocol ............................................................................... 5 Complications ............................................................................................ 7 Normal Arthrogram .................................................................................... 7 Abnormal Arthrogram ................................................................................ 9 Acromio-Clavicular Arthrography ............................................................. 16 Summary .................................................................................................. 16 2. Elbow Arthrography ....................................................... 20 Clara G.C. Ooi and Wilfred C.G. Peh Introduction ............................................................................................. 20 Normal Arthrogram .................................................................................. 25 Abnormal Arthrogram .............................................................................. 26 MR Arthrography ..................................................................................... 28 3. Wrist Arthrography ......................................................... 32 Isabelle Pigeau, Philippe Valenti, C. Sokolow, Stephane Romano and Philippe Saffar Introduction ............................................................................................. 32 Pre-Procedure Protocol ............................................................................. 33 Post-Procedure Protocol ............................................................................ 35 Pitfalls of Arthrography-CT ...................................................................... 38 Complications .......................................................................................... 38 Pathological Aspects .................................................................................. 38 4. Hip Arthrography ........................................................... 47 Laurent Sarazin, Alain Chevrot and Jacqueline C. Hodge Indications ................................................................................................ 47 Prearthrogram Preparation ........................................................................ 47 Technique ................................................................................................. 47 Postarthrogram Protocol ........................................................................... 50 Complications .......................................................................................... 50 The Normal Arthrogram .......................................................................... 50 Pathology .................................................................................................. 53
  6. 5. Knee Arthrography ......................................................... 62 Jacqueline C. Hodge Introduction ............................................................................................. 62 Indications ................................................................................................ 63 Contraindications ..................................................................................... 63 Equipment ................................................................................................ 63 Pre-Arthrography Protocol ........................................................................ 63 Technique ................................................................................................. 63 Normal Anatomy ...................................................................................... 65 Post-Procedure Protocol ............................................................................ 67 Complications .......................................................................................... 70 Pathology .................................................................................................. 70 6. Ankle Arthrography ........................................................ 78 Mary-Josee Berthiaume and Jacqueline C. Hodge Introduction ............................................................................................. 78 Prearthrogram Evaluation ......................................................................... 78 Indications ................................................................................................ 79 Equipment ................................................................................................ 79 Contrast Agents ........................................................................................ 79 Technique ................................................................................................. 79 Postarthrographic Recommendations ........................................................ 80 Complications .......................................................................................... 81 The Normal Ankle Arthrogram ................................................................ 81 Pathologic Conditions .............................................................................. 81 7. MR Arthrography ........................................................... 94 David R. Marcantonio, Robert D. Boutin and Donald Resnick Introduction ............................................................................................. 94 General Information ................................................................................. 94 Specific Joint Pathology ............................................................................ 96 Summary ................................................................................................ 103 8. Myelography ................................................................. 105 Jacqueline C. Hodge Introduction ........................................................................................... 105 Pre-Myelogram Preparation .................................................................... 105 Lumbar Puncture .................................................................................... 106 Cervical Puncture ................................................................................... 108 Contrast Agents ...................................................................................... 110 Post-Puncture Protocol ........................................................................... 111 Post-Procedure Protocol .......................................................................... 115 Complications ........................................................................................ 118 Pathology ................................................................................................ 118
  7. 9. Discography .................................................................. 124 Jacqueline C. Hodge Introduction ........................................................................................... 124 Lumbar Discography .............................................................................. 125 Thoracic Discography ............................................................................. 134 Cervical Discography .............................................................................. 134 Post-Procedure Care ................................................................................ 137 Interpretation ......................................................................................... 137 10. Percutaneous Blocks ..................................................... 140 Jacqueline Hodge Facet Blocks ............................................................................................ 140 Synovial Cysts ......................................................................................... 145 Sacroiliac Joint Block .............................................................................. 146 Interspinous Ligament Blocks ................................................................. 148 C1-2 Block ............................................................................................. 148 Miscellaneous Blocks .............................................................................. 149 11. Epidural Blocks ............................................................. 152 Jim Sloan Introduction ........................................................................................... 152 Epidural Injections .................................................................................. 152 Nerve Blocks ........................................................................................... 155 12. Tenography ................................................................... 163 Jacqueline C. Hodge Introduction ........................................................................................... 163 Patient Management ............................................................................... 168 Pathology ................................................................................................ 169 13. Bone Biopsies ................................................................ 175 Jacqueline C. Hodge Introduction ........................................................................................... 175 Biopsy Instruments ................................................................................. 179 Pre-Biopsy Considerations ...................................................................... 183 Post-Biopsy Care ..................................................................................... 183 Specimen Handling ................................................................................ 185 Complications ........................................................................................ 185 Additional Considerations ...................................................................... 185 MR-Guided Intervention ........................................................................ 186 14. Percutaneous Treatment of Osteoid Osteoma ............... 189 Jacqueline C. Hodge Introduction ........................................................................................... 189 Percutaneous Drill Resection .................................................................. 189 Percutaneous Radio-Frequency Ablation ................................................. 190 Post-Procedure Care ................................................................................ 190
  8. 15. Vertebroplasty ............................................................... 193 Jacqueline C. Hodge Introduction ........................................................................................... 193 Methyl Methacrylate ............................................................................... 194 Pre-Procedure Protocol ........................................................................... 194 Post-Procedure Protocol .......................................................................... 201 Assessing Your Intervention .................................................................... 201 Common Side Effects ............................................................................. 202 Complications ........................................................................................ 202 Future Developments in Vertebroplasty .................................................. 203 16. Ultrasound .................................................................... 204 Patrice-Etienne Cardinal and Rethy Chhem Introduction ........................................................................................... 204 Pre-procedure Preparation ....................................................................... 204 Pathological Conditions .......................................................................... 205 Appendix ....................................................................... 211 Contrast Reactions .................................................................................. 211 Prophylaxis for Contrast Reactions ......................................................... 213 Selecting a Contrast Medium .................................................................. 213 Index ............................................................................. 217
  9. Editor Jacqueline C. Hodge, M.D. Lenox Hill Hospital Department of Diagnostic Radiology New York, New York JHodge@LENOXHILL.net Chapters 1, 4-6, 8-10, 12-15 Contributors Mary-Josée Berthiaume Maryse Guerin Département de Radiologie Montreal General Hospital Hôpital Notre Dame Montreal, Quebec, Canada Université de Montréal Foreword Montréal, Québec, Canada email: mjb3gb@sympatica.ca David R. Marcantonio Chapter 6 Division of Musculoskeletal Radiology University of Texas Southwestern Medical Center Robert D. Boutin Dallas, Texas, U.S.A. University of California, San Francisco email: dmarca@mednet.swmed.edu San Mateo, California, U.S.A. Chapter 7 email: rboutin@stanfordalumni.org Chapter 7 G. Clara Ooi Patrice-Etienne Cardinal Department of Diagnostic Radiology Département de Radiologie Queen Mary Hospital Hôpital Saint-Luc The University of Hong Kong Université de Montréal Hong Kong Montréal, Québec, Canada email: cgcooi@hkucc.hku.hk email: etienne.cardinal@videotron.ca Chapter 2 Chapter 16 Wilfred C G Peh Alain Chevrot Department of Radiology Groupe Hospitalier Cochin Singapore General Hospital Service de Radiologie B Queen Mary Hospital Paris, France Singapore email: alain.chevrot@cch.ap-hop-paris.fr email: gdrpcg@sgh.gov.sg Chapter 4 Chapters 1, 2 Rethy Chhem Isabelle Pigeau Diagnostic Radiology Department Département de Radiologie National University Hospital Clinique Des Lilas–CEPIM National University of Singapore Les Lilas, France Singapore Chapter 3 email: dnrckr@nus.edu.sg Chapter 16
  10. Donald Resnick Jim Sloan Department of Diagnostic Radiology McGill University University of California, San Diego Department of Anaesthesia Department of Veterans Affairs The Royal Victoria Hospital Medical Center Montreal, Quebec, Canada San Diego, California, U.S.A. Chapter 11 email: asuptuesat@hotmail.com Chapter 7 C. Sokolow Institut Français de Chirurgie de la Main Stephane Romano Clinique du Trocadero Institut Français de Chirurgie de la Main Paris, France Clinique du Trocadero Chapter 3 Paris, France Chapter 3 Philippe Valenti Clinique Jouvenet Philippe Saffar c/o Clinique du Trocadero Institut Français de Chirurgie de la Main Paris, France Clinique du Trocadero Chapter 3 Paris, France Chapter 3 Laurent Sarazin Groupe Hospitalier Cochin Service re Radiologie B Paris, France email: laurent.sarazin@cch.ap-hop-paris.fr Chapter 4
  11. Foreword In times of overburdened daily practice, we are all looking for concise, practical books; books that are easy to consult and in which we rapidly find clear answers to specific problems or suddenly arising queries. Musculoskeletal Procedures: Diagnostic and Therapeutic belongs to this category of books. With the valuable collaboration of a select group of young dedicated musculoskeletal radiologists, the editor has revisited all of the chapters of her previous book, Musculoskeletal Imaging: Diagnostic and Therapeutic Procedures, with the fixed purpose of assisting residents in radiology, orthopaedics, and neurosurgery in their diagnostic and therapeutic procedures. In addition, this book offers the general radiologist a gamut of practical step-by-step techniques now currently in demand. This is a true vademecum book. Maryse Guerin, M.D. Assistant Professor of Neuroradiology Montreal General Hospital Montreal, Quebec, Canada
  12. CHAPTER 1 CHAPTER 1 Shoulder Arthrography Wilfred C.G. Peh and Jacqueline C. Hodge Introduction Arthrography is a long-established technique for evaluating internal structures of the shoulder joint not otherwise visualized by conventional radiographic and computed tomography (CT) techniques. Shoulder abnormalities such as rotator cuff tear, damage from previous dislocation, articular disease, capsular abnormality and long head of biceps tendon lesions can be demonstrated arthrographically. Although arthrographic findings are considered reliable, the introduction of newer diagnostic methods, such as magnetic resonance (MR) imaging,1-5 arthroscopy6-8 and ultrasound,9-13 have led to modifications of previous indications for arthrography. As with arthrography of other joints, successful shoulder arthrography depends on precise needle placement under fluoroscopy, high quality radiography supplemented by advanced imaging techniques, and accurate interpretation of arthrographic findings. Patient Preparation No special preparation is required for shoulder arthrography. Like other needling procedures, informed consent and careful questioning for possible allergic history should be obtained. For adults, shoulder arthrography is usually performed as an outpatient procedure, while for children, sedation or even general anesthetic may be required. As the patient may experience discomfort following the procedure, it may be advisable to ask the patient to be accompanied on departure from the radiology department, particularly if bilateral shoulder arthrography is performed. Indications • Rotator cuff tear • Recurrent or previous dislocation • Synovitis • Adhesive capsulitis • Loose bodies • Long head of biceps tendon abnormality • Evaluation of painful shoulder Contraindications • Local sepsis • General contraindications to MR imaging Musculoskeletal Procedures: Diagnostic and Therapeutic, edited by Jacqueline C. Hodge. ©2003 Landes Bioscience.
  13. 2 Musculoskeletal Procedures: Diagnostic and Therapeutic Equipment • Radiographic unit, ideally with a small focal spot 1 • Fluoroscopic unit, ideally with an overcouch X-ray tube • Sterile trolley • 22-gauge short-bevelled 9 cm lumbar puncture needle • Syringes (1-10 ml) and needles (18- to 23-gauge) of various sizes • Short plastic connecting tube • Sterile drapes • Skin cleansing solutions • Local anesthetic (1% lidocaine hydrochloride) • 1:1000 adrenalin • Nonionic contrast medium • Gadopentetate dimeglumine (for MR arthrography) • Normal saline (for MR arthrography) Preliminary Radiographs • Antero-posterior (AP) supine in internal rotation (bone exposure) • AP supine in external rotation (bone exposure) • AP erect with 20º caudal tilt (subacromial view) (soft tissue exposure) Technique The patient lies supine, with the arm and hand of the shoulder of interest placed next to the body. The patient’s palm should be in contact with the upper thigh. The skin over the shoulder region is cleansed and draped using strictly aseptic technique. The shoulder of interest is briefly screened fluoroscopically and positioned such that the field-of-view is centered over the intended puncture site, which is the gleno- humeral joint at the junction of the superior 2/3 and inferior 1/3 of the glenoid labrum (Fig. 1.1A). Maximum collimation is applied to minimize radiation and the area of interest is magnified. Fluoroscopic positioning up to this point can be performed by an assistant or alternatively by the radiologist prior to the start of the procedure. Subsequent fluoroscopic screening should ideally be controlled by the radiologist, using a footswitch. The articular surface of the glenoid should face slightly forwards. If not, that is if the glenohumeral articulation is in profile, the needle may damage the anterior cartilaginous labrum during its insertion. Slight adjustments to shoulder position may be made by placing of pads under the shoulder to ensure appropriate orientation of the glenoid (Figs. 1.1A and B). Under screening, the needle tip of the syringe containing the local anesthetic is placed over the intended puncture site. The syringe is held at a shallow angle in relation to the skin surface such that the radiologist’s hand is outside the radiation field. When the ideal position is located, the skin and subcutaneous tissue overlying the intended puncture site is anesthetized. At the end of the local anesthetic injection, my practice is to unscrew the syringe from the 23-gauge needle, leaving the needle embedded in the subcutaneous tissue/muscle. A quick fluoroscopic screening is then performed to check the position of the needle. Ideally, it should be seen end-on, that is vertically orientated, directly over the intended joint space target site (Fig. 1.1A).
  14. 3 Shoulder Arthrography 1 Fig. 1.1. A) Shoulder arthrography puncture technique. The position of the needle entry point (cross) is marked over the glenohumeral joint on the frontal view. B) Needle pathway is illustrated on the cross-sectional image. Keeping a mental picture of the orientation of the 23-gauge needle, this needle is quickly withdrawn and replaced, using the same puncture point, with a 22-gauge lumbar puncture needle. If the skin puncture site does not overlie the glenohumeral joint space, I would recommend choosing a more ideal skin puncture site, even if it means re-infiltrating local anesthetic. The needle should be advanced vertically, under intermittent screening to ensure that it does not deviate from its proper path, until mild resistance is felt. If it is in the glenohumeral joint, the tip of the needle may be seen to curve slightly, conforming to the joint articulation. The patient may experience slight discomfort at this point. The needle should be withdrawn, using a gentle rotating action, by about 1 mm to free its tip. My practice is then to inject a few drops of local anesthetic, using very gentle pressure, through the lumbar puncture needle. If there is no resistance to the flow of local anesthetic, it is very likely that the needle is within the joint space (Fig. 1.1B). If there is much resistance, the needle tip may still be embedded in the articu- lar cartilage and I would then withdraw the needle a further 1 mm and repeat the injection of local anesthetic. If resistance persists, then it may be worthwhile rescreening the joint before further injection of the contrast medium. Another advantage of injecting a small (0.5-1 ml) amount of local anesthetic is that it provides the patient with some relief from any discomfort associated with the procedure or pre-existing shoulder pain. The syringe containing the contrast medium is attached to the lumbar puncture needle using a short connecting tube. The contrast medium is then injected slowly under continuous screening to verify that the needle tip is within the joint. The contrast medium should flow away from the needle tip, outlining the humeral head articular surface or typically collecting at the subscapularis recess or the axillary pouch
  15. 4 Musculoskeletal Procedures: Diagnostic and Therapeutic (Fig. 1.2). If the contrast medium collects in a patch around the needle tip, its position is extra-articular. If this patch becomes increasingly dense or if parallel streaks 1 indicating intramuscular injection are seen, the contrast injection should be terminated immediately. It is important to fluoroscopically view the contrast flow continuously during injection, especially if a rotator cuff tear is suspected clinically (Fig. 1.3). In my institution, a nonionic contrast medium (Omnipaque 300) is routinely used. The amount of the contrast medium to be injected depends on whether a single or double-contrast arthrogram is required and whether the examination is to be followed by a CT or MR scan. Almost all the shoulder arthrograms currently performed in my institution are MR arthrograms, with the exception of the occasional CT arthrogram. 1:1000 adrenalin is usually pre-mixed with the contrast medium prior to injection with the advantages of: (1) decreased resorption of contrast; (2) decreased development of intra-articular effusion; (3) maintenance of longer coating and local contact of contrast with articular cartilage.14 In many institutions the fluoroscopic screening room is remote from the CT and MR suites, hence there is usually a delay between contrast injection and start of scanning. With adrenalin mixed with contrast, a good quality CT or MR arthrogram should still be achievable even after a 45-60 minute delay. I use a 1 ml tuberculin syringe for drawing precise amounts of adrenalin, a rule-of-thumb is to add 0.1 ml of 1:1000 adrenalin for each ml of the nonionic contrast medium to be injected.14 Contrast Agents Single Contrast Shoulder Arthrography 12-15 ml of nonionic contrast medium is injected. In adhesive capsulitis, pain development during injection may limit the total volume of contrast medium being introduced. Addition of a small amount of local anesthetic may allow more comfortable postprocedural manipulation. The single contrast technique is seldom used nowadays except for distention arthrography in patients with the frozen shoulder. In such cases, a painful shoulder may sometime be effectively treated using this technique.14-16 Double Contrast Shoulder Arthrography Two 4 ml volumes of nonionic contrast medium is injected, followed by 8-12 ml of air. The amount of air, which provides the negative contrast, to be introduced into the joint depends on the size of the patient. In modern practice, the double contrast study is usually part of the CT arthrographic examination.16-18 MR Shoulder Arthrography Up to 2 ml of nonionic contrast medium, containing up to 0.3 ml of 1:1000 adrenalin, is injected for the purpose of delineating the shoulder joint. This is followed by a 9 ml mixture of a 2 mmol/L solution of gadopentetate dimeglumine (Magnevist) diluted in normal saline. This solution is prepared prior to the whole procedure and although 9 ml is routinely injected in my institution, the total amount (up to 25 ml) to be injected depends on the joint capacity and body size of the patient. At present, the use of intra-articular gadolinium is yet to be approved by the
  16. 5 Shoulder Arthrography Fig. 1.2. Double contrast shoulder arthrogram. Extra- vasation of contrast and air 1 (white arrowheads) from the subscapularis recess (S), occurring during injection. The joint capacity is small, consistent with adhesive capsulitis. Smooth humeral head articular cartilage is outlined by the contrast medium (black arrow- heads). (B = biceps tendon sheath, A = axillary pouch). Fig. 1.3. Double contrast shoulder arthrogram showing rotator cuff tear. Leakage of contrast through a gap in the rotator cuff (white arrows) is demonstrated during contrast injection. (S = subscapularis recess). Food and Drug Administration (FDA) or the Health Protection Branch (HPB) and institutional review board permission is required. An alternative contrast agent is normal saline, but it suffers from the disadvantage of being indistinguishable from bursal fluid on MR imaging. Intravenous MR arthrography, though avoiding shoul- der joint puncture, produces inferior quality images compared with intra-articular arthrography and fails to distend the joint capsule adequately. Post-Puncture Protocol Following needle removal for each of the above-mentioned types of shoulder arthrography, the joint is gently manipulated to distribute the contrast medium evenly within the capsule. If a rotator cuff tear is strongly suspected clinically, more vigorous shoulder exercise may be employed to demonstrate the site of tear, especially if a small one is present. Single Contrast Shoulder Arthrography Radiographs • AP supine in internal rotation (bone exposure) • AP supine in external rotation (bone exposure) • AP erect (subacromial view) (soft tissue exposure)
  17. 6 Musculoskeletal Procedures: Diagnostic and Therapeutic Double Contrast Shoulder Arthrography Radiographs 1 • AP supine in external rotation (bone exposure) • AP supine in internal rotation (bone exposure) • AP erect in neutral (soft tissue exposure) • AP erect (subacromial views) (soft tissue exposure) CT Shoulder Arthrography • Radiographs as for double contrast shoulder arthrography • CT technique a) Patient is supine with arms in the neutral position (palms placed against the side of the upper thighs). b) 18 cm field-of-view (FOV), centered upon the glenohumeral joint. c) 3 mm-thick contiguous axial scans from upper acromio-clavicular joint to the inferior axillary pouch of the joint. d) Prospectively-obtained scans using bone algorithm (Window level 300- 400 HU, window width 1500-2000 HU), with retrospectively reconstructed scans using soft tissue algorithm (Window level 80-100 HU, window width 450-500 HU). e) In spiral scanners, 1.0 mm or 1.5 mm overlapping bone images are retrospectively reconstructed, followed by sagittal, coronal and oblique reformatted images. MR Shoulder Arthrography • Radiographs as for single contrast shoulder arthrography • MR technique a) Ensure that there are no contraindications to MR examination. b) Patient is supine, with palms placed against the sides of the upper thighs. c) The shoulder coil is positioned and secured around the shoulder of interest. d) Axial localizer (24 cm FOV; 5 mm thickness, 1 mm gap; 256 x 128 matrix; 0.75 number of excitations (NEX) e) Oblique coronal images (parallel to the plane of the supraspinatus muscle) - spin-echo (SE) T1 (14 cm FOV; 3 mm, 0 mm gap; 256 x 192; 2 NEX) - SE T1 fat saturation (sat) (14 cm FOV; 3 mm, 0 mm gap; 256 x 160; 1.5 NEX) - Fast SE T2 fat sat (14 cm FOV; 3 mm, 0 mm gap; 256 x 224; 2 NEX) f ) Oblique sagittal images (perpendicular to the supraspinatus muscle plane) - SE T1 (14 cm FOV; 4 mm, 0.5 mm gap; 256 x 192; 2 NEX)
  18. 7 Shoulder Arthrography - SE T1 fat sat (14 cm FOV; 4 mm, 0.5 mm gap; 256 x 160; 2 NEX) g) Axial (from the acromio-clavicular joint to the inferior axillary pouch) 1 - SE T1 (14 cm FOV; 3 mm, 0.5 mm gap; 256 x 160; 2 NEX) Complications After the procedure, the patient should be warned to expect some joint discomfort lasting up to one day. Complications are otherwise generally rare and are related to either needle placement or contrast reaction. Faulty needle placement may result in injection of contrast into the surrounding soft tissues, into the subacromial bursa or the biceps tendon sheath. These inadvertent injections are preventable by meticulous positioning of the needle tip.19 A rare complication is painful swelling of the joint developing within hours following the arthrogram due to irritation of the synovium by contrast medium. This chemical synovitis usually subsides after 1-2 days and may be treated by the aspiration of joint effusion. Infection is an extremely rare and a largely preventable complica- tion.20 Vasovagal syncope occurs infrequently. A minor allergic reaction in the form of urticaria affects 1 per 1000 patients, while serious allergic reaction or death from shoulder arthrography has yet to be reported.19 Morbidity from this procedure can be reduced by using nonionic contrast media and/or double contrast instead of single contrast examinations.21,22 Normal Arthrogram Conventional Shoulder Arthrography The glenohumeral space is initially visible as a curvilinear opacity between the humeral head and the glenoid surface. The axillary pouch, adjacent to the humeral neck, is best seen with the shoulder externally rotated while the subscapular recess, overlying the glenoid and lateral subscapular region, is best appreciated on the internal rotation view. The long head of biceps tendon is a tubular-shaped filling defect within the contrast-filled biceps tendon sheath which extends into the bicipital groove in the upper humeral metaphysis (Figs. 1.2 and 1.3). Sometimes, the biceps tendon can be seen running across the superior aspect of the humeral head. Before CT arthrography became commonly performed, axillary views were important in delineating the glenoid labra and the articular surfaces of the glenohumeral joint.15-17,19 CT Shoulder Arthrography The pouches and recesses of the shoulder joint seen on conventional arthrography are precisely delineated on CT. The relationship of the joint capsule to the surrounding muscles and the capsular insertion sites are well demonstrated. Using spiral CT, coronal and sagittal reformatted images are able to show the muscles of the rotator cuff in relation to the adjacent contrast- and air-filled joint capsule and bony structures. The contour and outline of the cartilaginous glenoid labra are clearly demonstrated on CT arthrography. The anterior labrum is usually triangular in shape compared to the more rounded posterior labrum, although normal variations in appearances of these structures exist (Fig. 1.4). Other intra-articular structures which may be depicted are the three glenohumeral ligaments and the long head of biceps tendon. In my
  19. 8 Musculoskeletal Procedures: Diagnostic and Therapeutic 1 Fig. 1.4. Normal CT shoulder arthrogram at mid-glenoid level. The triangular-shaped anterior glenoid labrum (straight arrow) and more rounded posterior labrum (curved arrow) are seen. The long head of the biceps tendon (arrowheads) is present within its tendon sheath in the bicipital groove. The anterior and posterior joint capsular attachments are delineated by air and contrast. experience, the superior glenohumeral ligament, which arises from the superior labrum and runs anteriorly and parallel to the coracoid process, is most constantly seen as it is the thickest of the three ligaments. The origin of the middle gleno- humeral ligament is from the superior labrum and it courses adjacent to the superior subcapularis tendon, often merging with and strengthening the anterior capsule. The inferior glenohumeral ligament consists of two bands—superoanterior and inferoposterior—which attach the inferior half of the labrum to the humerus. The middle and inferior glenohumeral ligaments are better seen on MR than on CT arthrography.18 The long head of the biceps tendon originates from the supraglenoid tubercle and superior glenoid labrum, takes an intra-articular course over the humeral head, and runs through the bicipital groove, before merging with the short head of the biceps in the distal third of the arm and inserting into the proximal forearm bones. On CT arthrography, this tendon is best appreciated in cross-section as a rounded filling defect within its air and contrast-filled sheath in the bicipital groove of the upper humerus (Fig. 1.4). Its origin from the superior glenoid can often be seen on axial or coronal reformatted images. Its path over the humeral head is however visualized with difficulty, due to partial volume averaging. Besides intra-articular structures, the surrounding bones such as the humeral head, bony glenoid, acromium, and the acromio-clavicular joint are nicely demonstrated on CT. The shape of the acromial arch can be determined using oblique sagittal reformatted images.23
  20. 9 Shoulder Arthrography MR Shoulder Arthrography MR arthrography combines the advantages of visualizing intra-articular structures, 1 made possible by capsule distention, with the inherent multiplanar capability of MR and superior delineation of soft tissue structures. The rotator cuff and other muscles and tendons are exquisitely demonstrated on T1-weighted images (WI). The bone marrow, intra- and inter-muscular fat and subcutaneous fat are also well seen with this sequence. T2-WI are useful for detection of soft tissue edema or other lesions, bone edema, contusion or other lesions, and fluid in the subacromial bursa and acromio-clavicular joint. Fat-suppression sequences improve visualization of fluid on T2-WI and of the rotator cuff by nulling the adjacent bright subacromial- subdeltoid peribursal fat on T1-WI.24-32 Besides demonstrating intra-articular structures such as the glenoid labra, long head of biceps tendon and loose bodies, the middle and inferior glenohumeral ligaments are visualized, particularly on the oblique sagittal images. Extra-articular structures forming the coracoacromial arch such as the coracoacromial ligament can also be seen (Figs. 1.5 and 1.6).24-32 The shape of the acromial arch, important in the impingement syndrome and suspected rotator cuff lesions, is best appreciated on oblique sagittal images.33 Abnormal Arthrogram Rotator Cuff Tears Plain radiographic clues to impingement and rotator cuff disease include narrowing of the acromio-humeral space, sclerosis of the greater tuberosity, inferior acromio-clavicular joint osteophytes and subacromial soft tissue calcification (Fig. 1.7). Fig. 1.5. Normal MR shoulder arthrogram—oblique coronal sections. A) Spin-echo (SE) T1-weighted image (WI) shows the supraspinatus muscle (large arrowheads) and tendon (small arrowheads), and normal marrow signal within the humeral head, glenoid and distal end of the clavicle (*). The supraspinatus fossa is marked with a star. B) Fat-saturated SE T1-WI shows the contrast-filled joint capsule, inferior gleno- humeral ligament (white arrows), and the superior (black arrowheads) and inferior (black arrows) glenoid labra more clearly. Normal sublabral sulcus is arrowed (small white arrows).
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