23204967

28th Annual

In-Training Examinationfor DiagnosticRadiology ResidentsRationalesSponsored by:Commission on EducationCommittee on Residency Training in Diagnostic Radiology

February 3, 2005

The American College of Radiology www.acr.org

American College of Radiology

Section VIII – Musculoskeletal

Figure 1A Figure 1B

200. You are shown axial T1- and T2-weighted MR images (Figures 1A and 1B) of a 23-year-old womanwith foot pain. Which one of the following is the MOST likely diagnosis?

A. Posterior tibial tendon tear

B. Subtalar coalition

C. Dysplasia epiphysealis hemimelica

D. Tarsal tunnel syndrome

Diagnostic In-Training Exam 2004


Question #200

Findings:Narrowing with closely opposed irregular articular interface at the medial subtalar joint with maldevelopmentof the sustentaculum tali, which slopes downward.

Rationales:A. Incorrect. Posterior tibial tendon tears may be incomplete with thickening of the tendon, type I, incomplete

with tendon attenuation, type II and complete, type III. Associated fluid at the tendon sheath is typical.Prominence of the medial soft tissues may be present. The posterior tibial tendon in the test case is normal.

B. Correct. The medial facet of the subtalar joint is one of the most common sites of developmental coalitionof the foot. Such unions may be fibrous, cartilaginous or bony. In either case, there is close approximationof the 2 bones, often with down-sloping of the sustentaculum tali as seen in the test case.

C. Incorrect. Dysplasia epiphysealis hemimelica—also known as Trevor’s disease, tarsal aclasis, tarsoepiphysealaclasis—is a development anomaly (dysplasia) in which a bony outgrowth, exostosis like in appearance,develops at an epiphysis or epiphysioid bone (epiphysealis) usually involving one side of the joint and oneside of the body (hemimelica). The most common sites are the ankle and knee. The abnormal appearanceof the medial subtalar joint in the test case represents coalition, not a bony outgrowth.

D. Incorrect. Tarsal tunnel syndrome is a compressive neuropathy involving the posterior tibial nerve resultingfrom any space-occupying lesion, behind and below the medial malleolus, beneath the flexor retinaculum.The tarsal tunnel in the test case is normal.

Citations:Stoller, Tirman, Bredella. Diagnostic Imaging Orthopaedics. Amirsys Inc. Salt Lake City, UT.

Resnick, Niwayama. Diagnosis of Bone and Joint Disorders. W.B. Saunders. Philadelphia, PA. Fourth Ed.



Figure 2

201. You are shown an AP view (Figure 2) of the pelvis and hips of a 44-year-old woman. What is theMOST likely diagnosis?

A. Osteopetrosis

B. Tuberous sclerosis

C. Renal osteodystrophy

D. Sickle cell disease



Question #201

Findings:Diffuse uniform sclerosis of the pelvis and hips with failure of differentiation between cortex and medullarycavity, status post hip fixation.

Rationales:A. Correct. Osteopetrosis is a sclerosing dysplasia involving a defect in osteoclastic resorption of the primary

spongiosa related to endochondral bone formation. Sclerosis is usually diffuse and uniform. Loss of thecortical medullary junction is typical. Alternating bands of sclerosis may also be present reflecting theperiodicity of the disease. In the adult form or delayed type, autosomal dominant variety, originallydescribed by Albert-Schoenberg, the patient’s life expectancy may be normal but the skeleton is brittle andprone to fracture.

B. Incorrect. Although the pelvis is a common site for osteoblastic deposits in patients with tuberous sclerosis,they are usually multiple and discrete rather than diffuse and uniform as in the test case.

C. Incorrect. Renal osteodystrophy does not produce such uniform widespread sclerosis with loss of thecortical medullary junction as in the test case. When there is extensive involvement, sclerosis tends to bemore patchy and ill-defined related to secondary hyperparathyroidism.

D. Incorrect. The sclerosis of sickle cell disease is secondary to infarction and osteonecrosis which overtime isreplaced by fibrosis and new bone formation. The diffuse, uniform sclerosis at the pelvis and hips withdiffuse loss of the cortical-medullary junction would be unusual.

Citations:Greenspan. Orthopaedic Radiology. Lipincott Williams Wilkins. Philadelphia, PA. Third Ed.

Resnick, Niwayama. Diagnosis of Bone and Joint Disorders. W.B. Saunders. Philadelphia, PA. Fourth Ed



202. You are shown a lateral radiograph (Figure 3A) and a non-contrast CT (Figure 3B) of a 9-year-oldboy with anterior leg bowing. What is the MOST likely diagnosis?

A. Intracortical osteosarcoma

B. Non-ossifying fibroma

C. Osteofibrous dysplasia

D. Aneurysmal bone cyst

Figure 3A Figure 3B



Question #202

Findings:There is a cortically based, expansile lesion involving the anterior tibia shaft.

The tibia is mildly bowed anteriorly.

The majority of the lesion is lucent, with a lobulated contour and sclerotic margins.

RationalesA. Incorrect. Intracortical osteosarcoma is the most uncommon form of osteosarcoma. They are diaphyseal,

usually arising in the femur or tibia. Intracortical osteosarcoma generally presents as lucency within thecortex that measures less than 4 cm, with surrounding sclerosis. If small, they may be mistaken for anosteoid osteoma or fibrous cortical defect.

B. Incorrect. Nonossifying fibromas may be mildly expansile, but they are not associated with bowing of thebone.

C. Correct. Osteofibrous dysplasia is a benign fibro-osseous lesion that is almost exclusively found in thetibia or fibula. It is a disorder of childhood, usually seen within the first 2 decades of life and often under10 years of age. The lesion is centered in the anterior cortex, and may be associated with anterior bowing.A lobulated lucency is seen, often with surrounding sclerosis. The appearance may mimic a nonossifyingfibroma, but the location and bow are key. Adamantinoma may be present in association with osteofibrousdysplasia. The two disorders cannot be differentiated one from the other by imaging.

D. Incorrect. Aneurysmal bone cysts are eccentric, lytic lesions that are usually found in the medullary cavity.They are most often metaphyseal, but may be present anywhere along a bone. Cortical and periosteallocations have been reported, but are unusual. The cortex overlying the lesion is expanded and if growth israpid, it may be destroyed.

Citations:Huvos AG. Bone Tumors: Diagnosis, Treatment, and Prognosis, 2nd Ed. WB Saunders Company, Philadelphia, PA,

1991.

Unni KK, Ed. Dahlin’s Bone Tumors: General Aspects and Data on 11, 087 cases, 5th ed. Lippincott-RavenPublishers, Philadelphia, PA, 1996



Figure 4BFigure 4A

203. You are shown frontal and lateral radiographs (Figures 4A and 4B) of a12-year-old boy who fellfrom his skateboard. What is the fracture type?

A. Tillaux

B. Triplane

C. Pilon

D. Maisonneuve



Question #203

Findings:A Salter IV fracture with a sagittal epiphyseal, transverse physeal and coronal metaphyseal orientation.

Rationales:A. Incorrect. A Tillaux fracture is a Salter type III avulsion of the anterolateral aspect of the distal tibial

epiphysis.

B. Correct. The radiograph shows a coronally oriented fracture of the distal metaphysis of the tibia, ahorizontally oriented fracture of the lateral aspect of the physis, and a sagittally oriented fracture of thedistal epiphysis, all of which comprise a triplane fracture. The injury results in part due to the partiallyfused tibial physis, closure progressing medial to lateral.

C. Incorrect. A pilon fracture is a comminuted fracture of the distal tibia and tibial plafond due to impactionof the talus into the tibia.

D. Incorrect. A Maisonneuve fracture involves the proximal fibula shaft and is associated with rupture of thedistal syndesmotic ligaments and widening of the tibia-fibular syndesmosis.

Citations:Greenspan. Orthopedic Radiology. A Practical Approach. 2nd ed. Gower Medical Publishing, NY, NY 1992.



Figure 5

204. You are shown an oblique coronal T1-weighted MR image (Figure 5) of a 45-year-old woman withchronic mild shoulder pain. What is the MOST likely diagnosis?

A. Parsonage-Turner syndrome

B. Chronic rotator cuff tear

C. Quadrilateral space syndrome

D. Suprascapular nerve entrapment



Question #204

Findings:Atrophy teres minor and deltoid musculature

Rationales:A. Incorrect. Parsonage-Turner syndrome (also known as acute brachial neuritis) is an idiopathic denervation

of the shoulder muscles resulting in pain and weakness. The muscles demonstrate high SI on T2-weightedimaging due to acute denervation edema and ultimately atrophy and fatty replacement. The suprascapularnerve and, therefore, the supraspinatus and infraspinatus musculature are typically involved. Axillary nerveinvolvement may occur but is less frequent.

B. Incorrect. While chronic tears of the rotator cuff tendons may be associated with muscle atrophy and fattyreplacement, no tears are demonstrated in the test case.

C. Correct. Quadrilateral space syndrome is caused by compression of the axillary nerve in the quadrilateralspace, usually by small fibrous bands or ganglion cysts and clinically manifests as mild shoulder pain.Axillary nerve dysfunction may eventually lead to atrophy of the teres minor and deltoid musculature.

D. Incorrect. The teres minor and deltoid muscles are supplied by the axillary nerve, not the suprascapularnerve. The suprascapular nerve innervates the supraspinatus and infraspinatus muscles, which appearnormal.

Citation:Kaplan, Helms, Dussault, Anderson, Major. Musculoskeletal MRI. WB Saunders Co., Philadelphia, PA. 2001



205. The radiographic appearance of SI joint widening is associated with ALL of the following EXCEPT:

A. Infection

B. Hyperthyroidism

C. Trauma

D. Renal osteodystrophy

Question #205

Rationales:A. Incorrect. Septic sacroiliitis may significantly erode the articular surfaces of the sacrum and ilium,

producing enough bone loss to create an appearance of joint widening.

B. Correct. Osteoporosis is the most characteristic feature of hyperthyroidism in the adult skeleton. In theimmature skeleton, there may be acceleration of skeletal maturity. Thyroid acropachy is an unusualmanifestation of thyroid disease usually observed after the treatment of hyperthyroidism at which time thepatient may be hypothyroid, euthyroid or even hyperthyroid. Periosteal new bone formation at the smallbones of the hands and feet is the characteristic radiographic finding. S-I joint involvement is not seen.

C. Incorrect. Trauma to the pelvis may result in diastasis at one or both SI joints producing a radiographicappearance of SI joint widening.

D. Incorrect. Secondary hyperparathyroidism is characteristic of renal osteodystrophy and may result insubchondral bone resorption at the SI joints.

Citations:Resnick, Niwayama. Diagnosis of Bone and Joint Disorders. W B Saunders, Philadelphia, PA Fourth Ed.



206. ALL of the following are associated with bone marrow edema on MRI EXCEPT:

A. Langerhans cell granuloma

B. Chondroblastoma

C. Giant cell tumor of bone

D. Osteoid osteoma

Question #206

Rationales:A. Incorrect. Langerhans cell granuloma (formally known as eosinophilic granuloma) is a benign disorder that

represents a focal tumor-like proliferation of Langerhans-type histiocytes. The lesions are usuallyintramedullary, but may arise in the cortex. They are lytic, most often with an oval shape. In the longbones, the lesion is usually diaphyseal. On MRI, intense edema is usually seen in the marrow andsurrounding soft tissues.

B. Incorrect. Like giant cell tumor of bone, chondroblastoma is an epiphyseal lesion. While the location issimilar, other features may be used to distinguish the two. Chondroblastoma is usually seen in patientsunder the age of 20 years. On plain film and CT, a well-defined sclerotic rim will be seen, often withmatrix mineralization. Chondroblastoma characteristically shows edema in the surrounding marrow onMR imaging. This is especially prominent with the “inflammatory” subtype.

C. Correct. Giant cell tumor of bone is usually an epiphyseal lesion, eccentrically located within the bone.Eighty percent of patients are between the ages of 20 and 50 years. The tumor generally lacks a definedsclerotic rim, and contains no matrix mineralization. In the absence of a pathologic fracture, bone marrowedema is not present.

D. Incorrect. Osteoid osteoma is a benign lesion that is characterized by a well-demarcated lucent nidus andmarked surrounding sclerosis when extraarticular. The nidus may be intramedullary, intracortical, orsubperiosteal. Because the nidus is usually quite small, it is often better depicted on CT than MR. TheMR will, however, show intense edema directing a search for the nidus that may otherwise be overlooked.

Citation:Kaplan PA, Helms CA, Dussault R, Anderson MW, Major NM. Musculoskeletal MRI. WB Saunders

Company, Philadelphia, PA, 2001



207. Concerning MRI of the knee, what does the “double PCL” sign indicate?

A. Bucket-handle tear of the medial meniscus

B. Anterior subluxation of the tibia

C. Anterior cruciate ligament rupture

D. Posterior cruciate ligament rupture

Question #207

Rationales:A. Correct. A bucket-handle tear is a longitudinal tear of the body of the meniscus with displacement of the

inner rim of that tear into the intercondylar notch of the knee. When such a tear involves the medialmeniscus, the flipped fragment characteristically lies underneath the curve of the posterior cruciateligament, usually mimicking it in contour and low signal intensity, thus giving rise to the “double PCL”sign.

B. Incorrect. Anterior subluxation of the tibia causes buckling of the PCL, not a “double PCL”.

C. Incorrect. Rupture of the anterior cruciate ligament leads to anterior subluxation of the tibia, thus causingbuckling of the PCL. When the edema and hemorrhage of an acute, complete ACL tear is resolved, theremaining ligament may be seen dropped within the notch, its slope almost parallel to the intercondylareminence, beneath the PCL, similar to but not characteristic of the “double PCL” sign.

D. Incorrect. Rupture of the PCL appears as swelling or discontinuity of the ligament.

Citation:Ref: Kaplan, Helms, Dussault, Anderson, Major. Musculoskeletal MRI. WB Saunders Co., Philadelphia, PA.

2001

Resnick, Kang: Internal derangements of joints: Emphasis on MR imaging. WB Saunders Co., Philadelphia,PA, 1997



208. Concerning the various arthropathies, which one of the following is TRUE?

A. Osteoarthritis of the hand and wrist has a predilection for the radioscaphoid joint compartment.

B. The inflammatory arthritides spare the bare areas of the joint.

C. Joint space narrowing is a late manifestation of gout.

D. New bone formation is characteristic of adult onset rheumatoid arthritis.

Question #208

Rationales:A. Incorrect. Osteoarthritis has a predilection for the radial aspect of the wrist, including the scaphoid

trapezium trapezoid complex and the trapezium first metacarpal joint compartment. The radioscaphoidjoint compartment, however, is typically spared unless there has been prior trauma. The PIP and DIPjoints are also preferentially involved.

B. Incorrect. The bare area of the joint refers to the intracapsular portion of bone not covered with articularcartilage. These areas therefore are more susceptible to the inflammatory process, often an early site oferosion before the articular cartilage is destroyed and the joint narrowed.

C. Correct. Although the hyaline articular cartilage is a common site for urate disposition and subsequenttophi, intervening areas of noninvolved cartilage maintain the joint space until late in the course of thedisease, when all of the cartilage may be destroyed. This differs dramatically from the inflammatoryarthritides where cartilage destruction is a more uniform and more rapid process.

D. Incorrect. The carpal bones and tarsal bones may fuse during the progression of adult onset rheumatoidarthritis as the joints of the wrist and foot are uniformly destroyed.

Otherwise, new bone formation is characteristically absent and is, rather, more typical of the sero-negativearthropathies. Bony ankylosis, periostitis, appositional new bone formation at the end of the bone(cupping), and ossification at the origin and insertion of ligaments and tendons (enthesopathy) aremanifestations of this productive tendency.

Citations:Resnick, Niwayama. Diagnosis of Bone and Joint Disorders. W B Saunders, Philadelphia, PA. Fourth Ed.



Question #209

Rationales:A. Incorrect. The scapula spine separates the supraspinatus and infraspinatus musculature. The tendons are

adjacent to one another.

B. Incorrect. There is no separation or interval between the adjacent infraspinatus and teres minor tendons.

C. Incorrect. The long head of the biceps tendon courses through the rotator cuff interval but does not defineits border.

D. Correct. The rotator cuff interval is a “space” between the supraspinatus and subscapularis tendonsthrough which the long biceps tendon travels from its origin on the supraglenoid tubercle to the bicipitalgroove.

Citations:

Bigoni BJ, Chung CB. MR imaging of the rotator cuff interval. Magn Reson Imaging Clin N Am 2004; 12:61-73.

Chung CB, Dwek JR, Cho Gj, et al. Rotator cuff interval: evaluation with MR imaging and MR arthrographyof the shoulder in 32 cadavers. J Comput Assist Tomogr 2000; 24(5):738-43.

209. The “rotator cuff interval” is defined as the anatomic space between which tendons?

A. Supraspinatus and infraspinatus

B. Infraspinatus and teres minor

C. Long head of biceps and subscapularis

D. Supraspinatus and subscapularis

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