Treatment of aneurysmal bone cysts by percutaneous CT-guided injection of calcitonin and steroid.

OBJECTIVES: To determine the efficacy and safety of percutaneous calcitonin and steroid injection in the treatment of aneurysmal bone cysts (ABCs). MATERIALS AND METHODS: Our study was IRB-approved and HIPAA-compliant. We reviewed pre- and post-procedural imaging studies and medical records of all CT-guided percutaneous injections of ABCs with calcitonin and steroid performed at our institution between 2003 and 2015. RESULTS: Treatment success based on imaging was categorized as substantial (51-100 %), partial (1-50 %), or none (0 %) by comparing radiographs of the lesion before and after treatment. Our study group comprised 9 patients (7 female, 2 male; mean age 19 ± 5 (range 12-25) years). ABCs were located in the pubis (n = 3), femur (n = 2), and humerus/scapula/ilium/sacrum (n = 1 for each). One patient did not have any clinical or imaging follow-up. For the other 8 patients, clinical and imaging follow-up ranged from 1 to 93 months (mean 16 ± 29 months). One patient had two injections, and 1 patient had three injections. Six out of eight patients (75 %) had complete symptomatic relief and 2 patients (25 %) had partial symptomatic relief after initial injection. Imaging follow-up revealed substantial imaging response in 4 out of 8 patients (50 %). There was a partial imaging response in 2 patients (25 %) and no imaging response in 2 out of 8 patients (25 %), and all 4 of these patients had local recurrence. There were no complications. CONCLUSION: Percutaneous CT-guided injection of ABCs with calcitonin and steroid is a safe and effective treatment. Lack of imaging response may necessitate more aggressive treatment to minimize local recurrence.

Limited magnetic resonance imaging of the lumbar spine has high sensitivity for detection of acute fractures, infection, and malignancy.

OBJECTIVE: The objective of this study is to determine how a limited protocol MR examination compares to a full conventional MR examination for the detection of non-degenerative pathology such as acute fracture, infection, and malignancy. MATERIALS AND METHODS: A sample of 349 non-contrast MR exams was selected retrospectively containing a 3:1:1:1 distribution of negative/degenerative change only, acute fracture, infection, and malignancy. This resulted in an even distribution of pathology and non-pathology. A limited protocol MR exam was simulated by extracting T1-weighted sagittal and T2-weighted fat-saturated (or STIR) sagittal sequences from each exam and submitting them for blinded review by two experienced musculoskeletal radiologists. The exams were evaluated for the presence or absence of non-degenerative pathology. Interpretation of the limited exam was compared to the original report of the full examination. If either reader disagreed with the original report, the case was submitted for an unblinded adjudication process with the participation of a third musculoskeletal radiologist to establish a consensus diagnosis. RESULTS: There were five false negatives for a sensitivity of 96.9 % for the limited protocol MR exam. Infection in the psoas, paraspinal muscles, and sacroiliac joint, as well as acute fractures in transverse processes and sacrum were missed by one or more readers. No cases of malignancy were missed. Overall diagnostic accuracy was 96.0 % (335/349). CONCLUSIONS: MR imaging of the lumbar spine limited to sagittal T1-weighted and sagittal T2 fat-saturated (or STIR) sequences has high sensitivity for the detection of acute fracture, infection, or malignancy compared to a conventional MR examination.

Imaging Findings of Metabolic Bone Disease.

Metabolic bone diseases are a diverse group of diseases that result in abnormalities of (a) bone mass, (b) structure mineral homeostasis, (c) bone turnover, or (d) growth. Osteoporosis, the most common metabolic bone disease, results in generalized loss of bone mass and deterioration in the bone microarchitecture. Impaired chondrocyte development and failure to mineralize growth plate cartilage in rickets lead to widened growth plates and frayed metaphyses at sites of greatest growth. Osteomalacia is the result of impaired mineralization of newly formed osteoid, which leads to characteristic Looser zones. Hypophosphatasia is a congenital condition of impaired bone mineralization with wide phenotypic variability. Findings of hyperparathyroidism are the result of bone resorption, most often manifesting as subperiosteal resorption in the hand. Renal osteodystrophy is the collection of skeletal findings observed in patients with chronic renal failure and associated secondary hyperparathyroidism and can include osteopenia, osteosclerosis, and "rugger jersey spine." Hypoparathyroidism is most commonly due to iatrogenic injury, and radiographic findings of hypoparathyroidism reflect an overall increase in bone mass. Thyroid hormone regulates endochondral bone formation; and congenital hypothyroidism, when untreated, leads to delayed bone age and absent, irregular, or fragmented distal femoral and proximal tibial epiphyses. Soft-tissue proliferation of thyroid acropachy is most often observed in the hands and feet. The findings of acromegaly are due to excess growth hormone secretion and therefore proliferation of the bones and soft tissues. Vitamin C deficiency, or scurvy, impairs posttranslational collagen modification, leading to subperiosteal hemorrhage and fractures. ©RSNA, 2016.

Retrospective analysis of intravertebral collateral enhancement in patients with central venous obstruction.

OBJECTIVE: To compare prevalence and patterns of intravertebral collateral enhancement in patients with and without central venous obstruction (CVO). MATERIALS AND METHODS: Chest CTs performed between 1/1/2000 and 12/15/2012 with reports containing terms indicating CVO were identified. All contrast enhanced CTs were examined for the presence of CVO and collateral venous pathways. If intravertebral collateral enhancement was present, the pattern was recorded as nodular, linear, or both. RESULTS: In 209 suspected cases of CVO, 53 (25 %) were confirmed with obstruction and 156 (75 %) were without obstruction. In patients with CVO, 47 % (25/53) demonstrated collateral venous flow through an intravertebral marrow pathway compared to 5 % (8/156) of patients without CVO (P < 0.0001). The most common level of enhancement was the upper thoracic spine, involving only the vertebral body. Nodular, linear, and combined nodular-linear enhancement patterns were seen with similar frequency. Nodular intravertebral collateral enhancement was mistaken for sclerotic metastases in 33 % (3/9) of cases. CONCLUSION: Intravertebral collateral enhancement was seen in almost half the patients with CVO and when nodular enhancement is present, it is important to differentiate between metastatic lesions and enhancement related to CVO.

Eosinophilic fasciitis-like disorder developing in the setting of multiple sclerosis therapy.

IMPORTANCE: Dimethyl fumarate received FDA approval in March 2013 for treatment of multiple sclerosis and has had a rapid uptake in the field due in large part to a favorable safety profile. Side effects of dimethyl fumarate include flushing, gastrointestinal discomfort, and peripheral eosinophilia. We report a case of eosinophilic fasciitis-like disorder occurring in the setting of oral dimethyl fumarate therapy. Eosinophilic fasciitis is rare and may be related to the peripheral eosinophilia known to occur with this medication. OBSERVATIONS: We present a case of a 36-year-old male treated with oral dimethyl fumarate for 16 weeks who developed a bilateral eosinophilic fasciitis-like disorder of the thighs. Magnetic resonance imaging revealed a fluid collection in the fascial plane and histopathologic examination revealed an inflammatory infiltrate with dermal and subcutaneous edema and sclerosis consistent with eosinophilic fasciitis. We discuss studies reporting peripheral eosinophilia with fumaric acid medications as well as the literature exploring possible mechanisms. CONCLUSIONS: With the anticipated widespread use of dimethyl fumarate for multiple sclerosis patients, it is important for practitioners to recognize the symptoms of eosinophilic fasciitis and be aware of a possible association of oral dimethyl fumarate treatment with the development of an eosinophilic fasciitis-like disorder.

MRI findings of rotator cuff myotendinous junction injury.

OBJECTIVE: The purpose of this article is to describe the MRI features of rotator cuff myotendinous junction injuries. MATERIALS AND METHODS: We retrospectively identified MRI cases with myotendinous junction injury of the rotator cuff muscles and reviewed clinical, imaging, and surgical records. MR images were reviewed independently by two musculoskeletal radiologists to grade myotendinous junction injuries (strain, partial tear, or complete tear) and to assess for concurrent tendon tears (partial or full thickness) and bone changes (fracture or contusion). RESULTS: The final study group comprised 16 subjects. The mean age was 38 years, with a majority of men (56%). The left shoulder was affected in 56% of subjects, with the dominant upper limb affected in 50%. The mean time between symptoms and MRI was 19 days. Subjects reported heavy lifting (19%), landing on the arm after a fall (19%), or prior shoulder therapeutic injection (25%). Myotendinous junction injuries affected the infraspinatus muscle (50%), followed by the supraspinatus (31%), subscapularis (25%), and teres minor (19%) muscles. About one fifth of subjects presented with more than one muscle affected, and 94% did not present with tears of the corresponding tendons. Most myotendinous junction injuries were strains (80%), followed by partial tears (20%). No complete tears were identified. There was no correlation between myotendinous junction injury and the presence of bone changes or the presence of tendon tears (p > 0.05). CONCLUSION: Rotator cuff myotendinous junction injuries affect mostly the infra-spinatus and supraspinatus muscles, usually in a strain pattern and without tear of the corresponding tendon attachment.

Association between distal ulnar morphology and extensor carpi ulnaris tendon pathology.

OBJECTIVE: The purpose of this study was to evaluate the association between distal ulnar morphology and extensor carpi ulnaris (ECU) tendon pathology. MATERIALS AND METHODS: We retrospectively reviewed 71 adult wrist MRI studies with ECU tendon pathology (tenosynovitis, tendinopathy, or tear), and/or ECU subluxation. Subjects did not have a history of trauma, surgery, infection, or inflammatory arthritis. MRI studies from 46 subjects without ECU tendon pathology or subluxation were used as controls. The following morphological parameters of the distal ulna were measured independently by two readers: ulnar variance relative to radius, ulnar styloid process length, ECU groove depth and length. Subjects and controls were compared using Student's t test. Inter-observer agreement (ICC) was calculated. RESULTS: There was a significant correlation between negative ulnar variance and ECU tendon pathology (reader 1 [R1], P = 0.01; reader 2 [R2], P < 0.0001; R1 and R2 averaged data, P < 0.0001) and ECU tendon subluxation (P = 0.001; P = 0.0001; P < 0.0001). In subjects with ECU tendon subluxation there was also a trend toward a shorter length (P = 0.3; P <0.0001; P = 0.001) and a shallower ECU groove (P = 0.01; P = 0.03; P = 0.01; R1 and R2 averaged data with Bonferroni correction, P = 0.08). ECU groove depth (P = 0.6; P = 0.8; P = 0.9) and groove length (P = 0.1; P = 0.4; P = 0.7) showed no significant correlation with ECU tendon pathology, and length of the ulnar styloid process showed no significant correlation with ECU tendon pathology (P = 0.2; P = 0.3; P = 0.2) or subluxation (P = 0.4; P = 0.5; P = 0.5). Inter-observer agreement (ICC) was >0.64 for all parameters. CONCLUSION: Distal ulnar morphology may be associated with ECU tendon abnormalities.

Optimization and standardization of technique for fluoroscopically guided suprascapular nerve blocks.

OBJECTIVE: The purpose of this study is to standardize the fluoroscopically guided suprascapular nerve block technique by optimizing patient positioning and imaging features that predict suprascapular notch visibility. MATERIALS AND METHODS: One hundred fifty-five consecutive patients underwent suprascapular nerve block from January 2010 through August 2012. The effect of arm position on suprascapular notch visibility and procedure parameters such as fluoroscopy time were evaluated using a chi-square test and a nonparametric Mann-Whitney U test, respectively. The coracoid process "in profile," a clear space between the coracoid process tip and the top of the glenoid, a visible glenohumeral joint space, and bisection of the glenoid by the projection of the scapular spine were identified as possible predictors for suprascapular notch visualization. Their ability to predict suprascapular notch visibility was assessed using positive predictive value (PPV), sensitivity, logistic regression, and receiver operating characteristic (ROC) curve analysis. RESULTS: Procedures performed with the affected arm positioned above the shoulder ("arm up") yielded increased suprascapular notch visualization (91% vs 47%; p<0.0001) and decreased fluoroscopy time (1.3 vs 2.0 minutes; p=0.002) compared with those performed with the affected arm positioned at the patient's side ("arm down"). The four imaging features had 91-95% PPVs for suprascapular notch visibility. Concurrent visualization of all four features yielded the highest discriminative accuracy for suprascapular notch visualization (area under the ROC curve [AUC], 0.870). Discriminative accuracy was good with visualization of only two features (AUC, 0.767-0.844) and fair with visualization of only one feature (AUC, 0.644-0.769). CONCLUSION: Positioning patients arm up and optimizing several key imaging features allows fluoroscopically guided suprascapular nerve blocks to be performed reliably and confidently.

Extrinsic wrist ligaments: prevalence of injury by magnetic resonance imaging and association with intrinsic ligament tears.

OBJECTIVE: The objective of this study was to determine the prevalence of extrinsic wrist ligament injury by magnetic resonance imaging and its association with intrinsic ligament tears. METHODS: We reviewed conventional magnetic resonance images performed over a 5-year period from adult patients in the setting of wrist trauma. Two musculoskeletal radiologists examined the integrity of wrist ligaments and presence of bone abnormalities. RESULTS: In a cohort of 75 subjects, extrinsic ligament injury was present in 75%, with radiolunotriquetral being most frequently affected (45%). Intrinsic ligament injury was present in 60%. Almost half of subjects had combined intrinsic and extrinsic ligament injury. Bone abnormalities were seen in 69%. The rate of extrinsic injury was higher in subjects with bone injury (P = 0.008). CONCLUSIONS: There is high prevalence of extrinsic ligament injury in the setting of wrist trauma, especially in the presence of bone abnormalities, with combined injury of intrinsic and extrinsic ligaments in about half of cases.

Musculoskeletal neoplasms: biopsy and intervention.

Percutaneous core needle biopsy and fine-needle aspiration are safe and cost-effective methods and can be important steps in the workup of a bone or soft tissue lesion. These procedures should be performed in collaboration with the orthopedic oncologist who performs the definitive surgery. In the extremities, attention to compartmental anatomy is paramount. With frozen section evaluation at the time of biopsy, the chances of a nondiagnostic specimen necessitating rebiopsy are minimized. The principles underlying the percutaneous approach to various lesions are valuable and can be applied to minimally invasive percutaneous therapy for bone and soft tissue lesions.

Tumors and diseases of the joint.

A variety of different diseases affect the synovium, including infection, noninfectious immunologic inflammatory conditions, degenerative arthroses, crystal deposits, trauma, and tumors. Tumors of the synovium are relatively uncommon. Any mesenchymal tumor may arise in the synovium, but most recapitulate its normal counterpart including synoviocytes, blood vessels, fat, and fibrous tissue. These tumors can arise in any synovial lined structures both within joints and in extraarticular locations. Most synovial tumors are benign. Malignant tumors are rare but important to recognize because many are aggressive and must be treated appropriately. Among common nonneoplastic conditions that affect the synovium and surrounding structures are crystal deposits such as monosodium urate crystals, calcium pyrophosphate dihydrate crystals, and hydroxyapatite crystals. These crystal deposits may be asymptomatic or cause severe pain or chronic joint destruction. Their accurate identification is important to guide appropriate therapy.

Well-differentiated osteosarcoma of the jaw bones: a clinicopathologic study of 15 cases.

Well-differentiated osteosarcoma of the jaw bones is rare, and is often confused with a variety of benign fibroosseous lesions. To better understand its clinicopathologic features, we reviewed our experience with 15 cases. The patients included 7 males and 8 females (age range 14 to 66 y; mean 42.8 y). Six of the tumors arose in the mandible, and 9 in the maxilla. Microscopically, the tumors were infiltrative, relatively hypocellular, and consisted of monomorphic, minimally atypical spindle cells that were usually arranged in fascicles. The tumor cells were intimately related to the surfaces of elongated trabeculae of neoplastic woven bone that lacked osteoblastic rimming. Nine patients were treated with wide excision, 2 patients with marginal excision, and 2 patients with excision and radiation therapy. After definitive therapy, there were no reports of recurrence or metastasis over an average follow-up of 34 months (range 1 to 80 mo). Well-differentiated gnathic osteosarcoma is a low-grade malignancy that may be successfully treated with wide local excision. The prognosis in our series was excellent.

Spontaneous osteonecrosis of the knee.

Spontaneous osteonecrosis of the knee presents with acute onset of severe, pain in elderly patients, usually female and usually without a history of trauma. Originally described as idiopathic osteonecrosis, the exact etiology is still debated. Evidence suggests that an acute fracture occurs as a result of chronic stress or minor trauma to a weakened subchondral bone plate. The imaging characteristics on MR reflect the age of the lesion and the symptoms. More appropriate terminology may be " subchondral insufficiency fracture of the knee" or "focal subchondral osteonecrosis".

Imaging of pseudoneoplastic masses associated with allografts.

OBJECTIVE: The objective of this study is to describe the imaging features of non-neoplastic masses suspected of being tumor recurrences adjacent to allografts. The allografts were utilized for the treatment of various musculoskeletal tumors. MATERIALS AND METHODS: We reviewed the medical records and imaging studies of 56 patients who were suspected of having recurrent tumors following surgical resection and allograft replacement treatment for a variety of musculoskeletal neoplasms. The imaging modalities included radiographs, CT, and MRI. RESULTS: There were 47 cases of recurrent tumors. All tumor recurrences were in the soft tissues of the surgical bed (41 patients), or in the native bone adjacent to the host/allograft junction (6 patients). None of the recurrences originated in the allografts. Nine patients suspected of having recurrences were discovered to have non-neoplastic masses. Five of these were very closely related to the allograft, wrapping around parts of the allograft, and the other 4 were in the surgical bed, 2 of which were abscesses and two were seromas. CONCLUSION: Most masses arising in the vicinity of allografts implanted following resection of musculoskeletal tumors represent recurrent neoplasms. A minority are reactive processes or abscesses or fluid collections. These "pseudoneoplasms," specifically those closely related to the allografts, have specific imaging characteristics that help distinguish them from recurrent tumors.

Idiopathic and diabetic skeletal muscle necrosis: evaluation by magnetic resonance imaging.

OBJECTIVE: Idiopathic and diabetic-associated muscle necrosis are similar, uncommon clinical entities requiring conservative management and minimal intervention to avoid complications and prolonged hospitalization. An early noninvasive diagnosis is therefore essential. We evaluated the magnetic resonance imaging (MRI) characteristics of muscle necrosis in 14 patients, in eight of whom the diagnoses were confirmed histologically. DESIGN AND PATIENTS: Two experienced musculoskeletal radiologists performed retrospective evaluations of the MRI studies of 14 patients with the diagnoses of skeletal muscle infarction. In 10 cases gadolinium-enhanced (T1-weighted fat-suppressed) sequences were available along with T1-weighted, T2-weighted images and STIR sequences, while in four cases contrast-enhanced images were not available. RESULTS: Eight patients had underlying diabetes and in six patients the cause of the myonecrosis was considered idiopathic. T1-weighted images demonstrated isointense swelling of the involved muscle, with mildly displaced fascial planes. There was effacement of the fat signal intensity within the muscle. Fat-suppressed T2-weighted images showed diffuse heterogeneous high signal intensity in the muscles suggestive of edema. Perifascial fluid collection was seen in eight cases. Subcutaneous edema was present in seven patients. Following intravenous gadolinium administration, MRI demonstrated a focal area of heterogeneously enhancing mass with peripheral enhancement. Within this focal lesion, linear dark areas were seen with serpentine enhancing streaks separating them in eight cases. In two cases, a central relatively nonenhancing mass with irregular margins and peripheral enhancement was noted. The peripheral enhancement involved a significant part of the muscle. No focal fluid collection was noted. CONCLUSIONS: We believe that the constellation of imaging findings on T1- and T2-weighted images and post-gadolinium sequences is highly suggestive of muscle necrosis. We consider certain specific findings on gadolinium-enhanced images to be characteristic. The findings reported here should provide radiologists with useful information in making the diagnosis of skeletal muscle necrosis without resorting to invasive procedures.

MR appearance of SONK-like subchondral abnormalities in the adult knee: SONK redefined.

OBJECTIVE: To investigate the MR characteristics of SONK-like (spontaneous osteonecrosis of the knee) subchondral abnormalities in the adult atraumatic knee and to recategorize these patients into two subgroups: a subacute to chronic process associated with osteoarthritis and an acute process associated with insufficiency fractures. DESIGN: We retrospectively examined the knee MRIs of 39 patients with non-specific interpretations of osteochondral abnormalities. PATIENTS: There were a total of 52 subchondral lesions without any known traumatic event and no prior surgery. All lesions evaluated had MR features previously ascribed to SONK. Several MR characteristics were then assessed: presence or absence of a line, size, zonal location, T1 and T2 signal, associated marrow edema, associated ipsilateral meniscal tear, and associated ipsilateral cartilage defects. RESULTS AND CONCLUSIONS: The abnormalities with linear components (insufficiency fractures) tended to be larger (P<0.01) and were associated with a severe amount of marrow edema (P<0.0001) consistent with an acute process. The non-linear abnormalities were more associated with cartilage defects (P=0.01) and less marrow edema consistent with osteoarthritis and a subacute to chronic process. This association of SONK-like abnormalities with osteoarthritis and insufficiency fractures casts doubt on the validity of the term "spontaneous osteonecrosis" as it is currently applied, and further investigation into the separate etiologies of these subchondral marrow lesions is needed.

Musculoskeletal ultrasound: an alternative imaging modality for sports-related injuries.

Advanced technology and increasing clinical experience have established sonography as a reliable imaging modality for sports-related injuries. Tears of muscles and tendons, tendinosis, and tenosynovitis are promptly diagnosed using ultrasound. Dynamic assessment of joints can be performed, allowing diagnoses of conditions that may remain undetected when evaluated with conventional magnetic resonance imaging. Sonography provides expeditious image guidance for procedures such as drainage of fluid collections and cysts. This article reviews the applications of sonography to sports-related injuries in which its diagnostic performance may be comparable to magnetic resonance imaging.