A clinico-radiological review of chronic non-bacterial osteomyelitis in paediatrics, adolescents, and adults: demystifying a forgotten differential.

Chronic non-bacterial osteomyelitis (CNO), also known as non-bacterial osteitis, is a chronic autoinflammatory disease of unknown aetiology that primarily occurs in the paediatric population, although rare cases of adult-onset disease also exist. CNO has non-specific clinical and radiological presentations, and the affected population often present with bone pain of insidious onset secondary to sterile bony inflammation that can be associated with swelling, focal tenderness, and warmth at the affected sites. The pattern of bony involvement appears to be dependent on the age of onset, with adults frequently having axial skeletal lesions and children and adolescents often being affected in the appendicular skeletal sites. CNO is a diagnosis of exclusion, and imaging is heavily relied on to identify and characterise the bony lesions in addition to exclude diseases that can mimic CNO. Magnetic resonance imaging is often the reference standard with biochemical and histopathological findings being complementary. Although combining imaging methods can be used to facilitate the diagnosis, a single technique could be adequate depending on the clinical picture. Given the relatively rare incidence of CNO, limited awareness of the disease among care providers, and its similarity in clinical and radiological presentation to various bony diseases, there are often long delays in diagnosis, with adults being unfavourably affected compared to paediatrics and adolescents. This review of CNO will describe the condition, overview its clinical presentation, highlight the radiological features, and emphasise clinical pearls that can aid in diagnosis and ruling out the mimics.

Periarticular calcifications.

Periarticular calcification and ossification is a frequent finding on imaging and may sometimes pose a diagnostic challenge. The differential diagnoses for this radiological finding are wide and can be classified into broad groups such as idiopathic, developmental, trauma, burns, infection, tumor, connective tissue disease, crystalline, metabolic, vascular, and foreign bodies. With careful consideration of the clinical and imaging findings as well as awareness of mimickers of periarticular mineralization, the list of differential diagnoses can be narrowed down. This article aims to review the clinical-radiologic findings of periarticular calcified or ossified lesions with relevant imaging illustrations.

Detection of occult, undisplaced hip fractures with a dual-energy CT algorithm targeted to detection of bone marrow edema.

The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between January 1, 2011 and January 1, 2013 with clinical suspicion of hip fracture and normal radiographs were included. All CT scans were performed on a dual-source, dual-energy CT system. VNC images were generated using prototype software and were compared to regular bone reconstructions by two musculoskeletal radiologists in consensus. Radiological and/or clinical diagnosis of fracture at 30-day follow-up was used as the reference standard. Twenty-one patients were found to have DECT-VNC signs of bone marrow edema. Eighteen of these 21 patients were true positive and three were false positive. A concordant fracture was clearly seen on bone reconstruction images in 15 of the 18 true positive cases. In three cases, DECT-VNC was positive for bone marrow edema where bone reconstruction CT images were negative. Four patients demonstrated no DECT-VNC signs of bone marrow edema: two cases were true negative, two cases were false negative. When compared with the gold standard of hip fracture determined at retrospective follow-up, the sensitivity of DECT-VNC images of the hip was 90 %, specificity was 40 %, positive predictive value was 86 %, and negative predictive value was 50 %. Our initial experience would suggest that DECT-VNC is highly sensitive but poorly specific in the diagnosis of hip fractures in patients with normal radiographs. The value of DECT-VNC primarily lies in its ability to help detect fractures which may be subtle or undetectable on bone reconstruction CT images.

Evolving Practice Patterns Over Two Decades (1993-2013) in the Management of Desmoid-type Fibromatosis in British Columbia.

AIMS: Due to the rarity and varied natural history of desmoid-type fibromatosis, evidence-based treatment standards for this disease remain lacking. This study evaluated outcomes in patients with desmoid-type fibromatosis managed at a Canadian institution over two decades. MATERIALS AND METHODS: Records of 227 patients with desmoid-type fibromatosis referred from 1990 to 2013 were retrospectively reviewed to investigate management strategies including active surveillance, surgery, radiation therapy, cryoablation, and systemic therapy, including tamoxifen and chemotherapy. RESULTS: Thirty-two per cent of cases were men, median age 40 years, median tumour size 5.4 cm. Initial treatments were surgery (79%), tamoxifen (13%), radiation therapy (5.0%), chemotherapy (1.8%) and cryoablation (1.2%). Active surveillance was used upfront in 26% of cases, most after 2005. At a median follow-up of 77 months, one patient died of disease, 13 died of unrelated causes and the remainder were alive with no evidence of disease (56%), stable/responding disease (33%) or progressive disease (4%). The recurrence rate was 25% after upfront surgery. Response rates and disease control rates were 40% and 76% for active surveillance; 68% and 96% for radiation therapy; 31% and 67% for tamoxifen; and 53% and 80% for chemotherapy. On univariable analysis, factors associated with a higher recurrence after initial surgery were young age (P = 0.012), male gender (P = 0.012) and extremity location (P = 0.005). On multivariable analysis, only young age was significantly associated with recurrence risk (P = 0.010). CONCLUSIONS: Active surveillance was associated with spontaneous regression and long-term disease control consistent with other studies. Primary radiation therapy appeared to provide a similar response and disease control compared with systemic treatments and may be a viable option for patients who are not candidates for surgery or active surveillance.

Dual energy computed tomography in tophaceous gout.

OBJECTIVE: To evaluate the potential utility of a dual energy CT (DECT) scan in assessing urate deposits among patients with tophaceous gout, and obtain computerised quantification of tophus volume in peripheral joints. METHODS: 20 consecutive patients with tophaceous gout and 10 control patients with other arthritic conditions were included. DECT scans were performed using a renal stone colour-coding protocol that specifically assessed the chemical composition of the material (ie, urate coloured in red, calcium coloured in blue). An automated volumetric assessment of DECT was used to measure the volume of urate deposits in all peripheral joint areas. RESULTS: All 20 patients with gout showed red colour-coded urate deposits on their DECT scans, whereas none of 10 controls showed urate deposits. DECT scans revealed a total of 440 areas of urate deposition in 20 patients, whereas physical examination showed 111 areas of urate deposition (mean 22 vs 6 per patient, respectively, p<0.001). Total urate volume in a given patient ranged from 0.63 cm(3) to 249.13 cm(3), with a mean of 40.20 cm(3). CONCLUSIONS: DECT scans can produce obvious colour displays for urate deposits and help to identify subclinical tophus deposits. Furthermore, tophus volume can be measured by DECT scans through an automated volume estimation procedure.

CT-guided bone biopsy: Initial experience with a commercially available hand held Black and Decker drill.

PURPOSE: To describe the use of a simple commercially available Black and Decker hand based drill in performing CT-guided bone biopsies. MATERIALS AND METHODS: Three international institutions were enrolled in the study. In each centre, a fellowship trained musculoskeletal radiologist directed the assessment of a hand based commercial drill for performing CT-guided bone biopsies. A specially designed component was engineered which allowed the connection of a standard bone biopsy set to a commercial drill. The component was distributed to the three centres involved. Over a 3-year period, data from all three institutions was collected. Information regarding technical success, diagnostic data and complication rates were all collated to assess the technical feasibility of this technique. RESULTS: In total 68 patients underwent bone biopsy using a hand held commercial drill. Technical success was achieved in 65 patients. Diagnostic material was obtained in 53 patients. Non-diagnostic material was obtained in 12 patients. Five out of the 12 patients with non-diagnostic material had repeat biopsies with diagnostic material obtained in 2 of these. No major complications occurred in any patient. CONCLUSION: CT-guided bone biopsy using a hand held commercial drill has a technically high success rate with minimal complications.

The imaging features of gastrointestinal stromal tumours.

Gastrointestinal stromal tumours (GISTs) are a rare group of mesenchymal neoplasms that occur predominantly in the gastrointestinal tract. Previously GISTs were classified as smooth muscle tumours referred to as leiomyomas, leiomyosacromas or leiomyoblastomas. However, with the advent of immunohistochemistry, GISTs are now defined by the identification of cKit positivity. This is now used to select patients with metastatic disease who may respond to chemotherapeutic agents such as the tyrosine kinase inhibitor, STI-571. In this pictorial essay we have attemped to describe the range of imaging findings of GISTs that can suggest a pre-biopsy diagnosis.

Lesions of cartilage and bone around the knee.

A variety of bone and cartilage abnormalities can be demonstrated on magnetic resonance imaging (MRI), which can play an important role in the diagnosis and management of these abnormalities. Ischemic bone lesions, including medullary bone infarction, primary osteonecrosis, and the osteochondroses, can be precisely evaluated as to their anatomic locations and relationship to overlying cartilage. Osteochondritis dissecans may also be diagnosed and staged. Presence of subchondral fractures and bone contusions, which are frequently associated with ligament and meniscal injuries, can also be diagnosed and followed; these conditions may play a role in the evolution of osteoarthritis. The changes of osteoarthritis, including cartilage abnormalities, cyst formation, and loose bodies, can be evaluated; this evaluation may be important in the assessment of therapies. Stress fractures often have characteristic appearances, and MR may be used in making this diagnosis, especially when symptoms and other imaging are unclear. Diffuse marrow disorders including hemoglobinopathies and neoplasia are also well demonstrated.

Pseudopermeative skeletal lesions.

Permeative bone lesions are well known to radiologists and usually invoke a differential diagnosis that includes aggressive lesions such as round cell malignancies and infection. In contrast to permeative lesions, which demonstrate multiple small holes at the endosteal surface of the cortex secondary to a medullary process, we describe a series of 19 patients (seven with aggressive osteoporosis, eight with prior radiation therapy and four with hemangiomas) who demonstrated multiple tiny lucencies in the cortex which were superimposed on the medullary space and mimicked a permeative pattern radiographically. We termed this a pseudopermeative pattern. Recognition of a pseudopermeative pattern may allow a less sinister differential diagnosis to be considered and may avert unnecessary biopsy in many instances.

Carotid artery stenosis in patients who have undergone radiation therapy for head and neck malignancy.

Although it is established that small and medium sized arteries undergo extensive radiation damage, the effect on large vessels such as the carotid arteries is less well understood. We sought to determine if an increased severity of carotid artery stenosis is present in patients who have undergone radiotherapy for head and neck tumours. 45 patients aged 43-90 years (average 67) with head and neck malignancies treated with radiotherapy underwent colour Doppler ultrasonographic scanning of the carotid arteries. These patients were compared with a population of asymptomatic historical controls. 60% of patients demonstrated stenosis ranging from 21 to 86%. 38% of patients demonstrated a stenosis greater than or equal to 50%. Carotid artery stenosis appears to be increased in patients who have previously undergone treatment with radiotherapy to the head and neck regions compared with controls (p < 0.001). These findings suggest that radiation has an adverse effect on large vessels. Colour Doppler follow-up may be indicated for patients receiving head and neck radiation therapy.

MR imaging features of bizarre parosteal osteochondromatous proliferation of bone (Nora's lesion).

The purpose of this study was to review the imaging findings of three patients with bizarre parosteal osteochrondromatous proliferation of bone (BPOP). The plain radiographs and MRI images of three patients with BPOP were obtained and retrospectively reviewed. In two cases, BPOP involved the feet. In one case BPOP involved the hand. In all three cases, plain radiographs showed a well-defined calcium containing mass adjacent to the cortical surface of the adjacent bone. The underlying bone appeared normal in all cases. On MRI, the lesion was of low signal intensity on T1 weighted sequences in all cases. On FSE T2 weighted and STIR sequences, the lesion was of high signal in all cases. The cortex, medullary cavity and adjacent soft tissues appeared normal in all cases. While BPOP is rare and often confused with a variety of both benign and malignant lesions, there are specific radiological findings that may help to distinguish BPOP from many of its mimickers.

Lipomatous hemangiopericytoma: a morphologically distinct soft tissue tumor.

Hemangiopericytoma of soft tissue is a controversial pathologic entity. The relative nonspecificity of the characteristic branching capillary pattern and cytologic features of the constituent cells, in addition to the lack of a distinct immunohistochemical staining profile, has resulted in uncertainty and a lack of consensus regarding this subgroup of tumors. Notwithstanding the doubt surrounding this entity, a morphologically unique variant, designated lipomatous hemangiopericytoma, was reported in 1995. To our knowledge, there have been no further reports of these tumors since the original description. We describe a lipomatous hemangiopericytoma that arose within the thigh of a 41-year-old woman. The tumor presented as a slowly enlarging, minimally tender, pulsatile mass. The tumor was completely excised and was found to be composed of an admixture of typical hemangiopericytoma and predominantly mature adipose tissue. Unlike previous descriptions of this entity, the current example exhibited a full range of adipocyte differentiation, including many multivacuolated adipocytes of variable size with characteristic nuclear scalloping (lipoblast-like cells). The mitotic count was less than 2 per 10 high-power fields examined. The clinical course has been benign during the short follow-up period. We discuss the pathologic features, including the immunohistochemical staining profile and ultrastructural appearance of this distinctive tumor, and briefly discuss the relationship between hemangiopericytoma and solitary fibrous tumor of soft tissue, a neoplasm with many clinical and pathologic similarities.

CT evaluation of periacetabular osteotomies.

We have previously described a simple and reproducible three-dimensional technique of CT for the measurement of the cover of the femoral head in acetabular dysplasia in adults. We now describe the application of this technique in ten patients with symptomatic dysplasia to assess the degree and direction of dysplasia and to measure the cover obtained at acetabular osteotomy. The indices obtained gave a useful indication of the degree and direction of the dysplasia and confirmed which components had been used most efficiently to achieve cover. The information is easily presented in graphical form and gives a clearer indication of the cover obtained than the indices derived from plain radiographs.

Talocalcaneal coalition. Diagnosis with the C-sign on lateral radiographs of the ankle.

We analysed 42 weight-bearing lateral radiographs of the ankle, 20 of which were from patients with a clinical and plain radiological diagnosis of talocalcaneal coalition (TCC) who subsequently had CT. The remainder were from 22 healthy volunteers with no clinical findings suggestive of hindfoot pathology. Four observers, blinded to the CT findings, independently evaluated the radiographs on two separate occasions. With the 95% confidence interval and using the CT findings as the comparison we calculated the sensitivity, specificity, accuracy, and positive and negative predictive values for the C-sign, and for other signs known to be associated with TCC. Similarly, we also calculated the interobserver and intraobserver reliability for these signs using the kappa statistic. Our results suggest that the C-sign is highly sensitive and specific for TCC. It is an accurate indicator and significantly more reliable than other previously recognised radiological signs of TCC. Features of the C-sign, however, cannot be relied upon to indicate whether the TCC is fibrous or bony.

Ultrasonography of pathologically proved choroidal melanoma with a high-resolution small-parts scanner.

Between March 1983 and March 1985, 13 patients with choroidal melanoma underwent ultrasonography with a high-resolution small-parts scanner. The patients subsequently underwent enucleation, and the specimens were examined histopathologically. We reviewed the ultrasonograms for the presence of choroidal excavation, rupture through Bruch's membrane, retro-orbital fat shadowing, acoustic texture and retinal detachment. Comparison with the histopathological results showed that when conventional diagnostic criteria were used, most cases of rupture through Bruch's membrane were missed owing to the limits of resolution. No patients with homogeneous acoustic texture had pathological evidence of tumour necrosis or hemorrhage, while most of those with inhomogeneous texture did. The results suggest that high-resolution small-parts scanning may lead to reassessment of the conventional criteria for the diagnosis of intraocular melanomas.

Imaging techniques of the shoulder: present perspectives.

Through its ability to evaluate the individual components of the rotator cuff, the labral-capsular complex, the subacromial and subdeltoid spaces, and the glenoid, humerus, clavicle, and acromion, MRI provides a means of comprehensively evaluating the shoulder. Further advances in the use of intra-articular MRI contrast agents will undoubtedly enhance the role of MRI in the evaluation of subtle labralcapsular pathology. Although they are experimental, kinematic studies of the shoulder may provide valuable insight into the pathogenesis of disorders such as impingement syndrome. The ability of MRI to provide detailed pathologic information about individual components of the shoulder, particularly the rotator cuff, presents a challenge to shoulder surgeons. Patient symptomatology should be correlated with MRI findings and the clinical significance attached to different pathologies reevaluated. Through rigorous confirmation of MRI findings, dedicated therapeutic algorithms can be established based on detailed clinicopathologic data. Present and future surgical and nonsurgical management of the shoulder will undoubtedly be shaped by MRI.

Multimodality imaging features of hereditary multiple exostoses.

Hereditary multiple exostoses (HME) or diaphyseal aclasis is an inherited disorder characterised by the formation of multiple osteochondromas, which are cartilage-capped osseous outgrowths, and the development of associated osseous deformities. Individuals with HME may be asymptomatic or develop clinical symptoms, which prompt imaging studies. Different modalities ranging from plain radiographs to cross-sectional and nuclear medicine imaging studies can be helpful in the diagnosis and detection of complications in HME, including chondrosarcomatous transformation. We review the role and imaging features of these different modalities in HME.

Intravascular embolisation and surgical resection of a giant neurofibroma with intratumoural haemorrhage.

The use of pre-operative embolisation has been described for small neurofibromas, but not for giant lesions. Advances in embolisation techniques are extending the indications for this procedure, in particular to assist with operative intervention on a range of lesions. This case report describes a 45-year-old male with a giant neurofibroma who underwent embolisation to stabilise intratumoural haemorrhage and to assist with haemostasis during the subsequent surgical resection. Minimal transfusion was required and the patient has made a good recovery. This case demonstrates that pre-operative embolisation of these large and challenging lesions is technically feasible and appears to be beneficial in reducing perioperative blood loss and morbidity.