Miss Katie Clark: Pioneer of Standardization of Radiographic Projections.

This history page in the series "Leaders in MSK radiology" is dedicated to the memory and achievements of the British radiographer Kathleen C. Clark, recognized as a pioneer of standardization of radiographic projections.

A novel use of cone beam CT: flexion and extension weight-bearing imaging to assess spinal stability.

PURPOSE: To assess spinal stability in different physiological positions whilst weight-bearing. METHODS: A cone beam CT scanner (CBCT) was used to identify any abnormal motion in the spine in different physiological positions whilst weight-bearing. The lumbar spine was assessed in 6 different patients with a comfortable neutral standing position and standing flexion and extension images in selected patients. Seated, weight-bearing flexion and extension images of the cervical spine were obtained in a further patient. Clinical indications included stability assessment post-trauma, post-surgical fusion and back pain. The projection images were reconstructed using bone and soft tissue algorithms to give isotropic CT images which could be viewed as per conventional multi-detector CT images. The flexion and extension CBCT data were fused to give a representation of any spinal movement between the extremes of motion. RESULTS: The flexion and extension weight-bearing images gave anatomical detail of the spine. Detail of the surgical constructs was possible. Dynamic structural information about spinal alignment, facet joints, exit foramina and paraspinal musculature was possible. The effective dose from the neutral position was equal to that of supine, multi-detector CT. CONCLUSION: CBCT can be used to image the lumbar and cervical spine in physiological weight-bearing positions and at different extremes of spinal motion. This novel application of an existing technology can be used to aid surgical decision making to assess spinal stability and to investigate occult back and leg pain. Its use should be limited to specific clinical indications, given the relatively high radiation dose.

Neoplastic Elbow Diseases and Mimickers.

Tumors around the elbow are infrequent, and delayed diagnosis is a common theme because of the low incidence and lack of familiarity. However, just like any other site, the radiologic work-up of musculoskeletal tumors around the elbow remains the same, with plain films the first investigation in a patient with a suspected bone tumor and ultrasound the first modality to evaluate a soft tissue lump. The management of both bone and soft tissue tumors around the elbow is unique because of a large number of important structures in an anatomically confined space and little normal tissue to spare without severely compromising the joint's function. Many benign nonneoplastic entities can mimic bone and soft tissue tumors on imaging. It is important to keep the characteristic imaging appearance in mind while formulating a differential diagnosis to avoid an unnecessary additional work-up. This article reviews the most common benign and malignant bone and soft tissue tumors around the elbow, mimickers, imaging features, and current therapeutic concepts.

Intraosseous lipomas originating from simple bone cysts.

PURPOSE: Fatty or part-fatty intraosseous lesions are occasionally encountered while imaging the skeletal system. A number of case reports have proposed involution of calcaneal bone cysts to intraosseous lipomas, but this has never been proven. This paper sets out to prove that simple bone cysts (SBCs) can involute to fatty lesions indistinguishable from intraosseous lipomas. MATERIALS AND METHODS: The pathology and PACS databases at 2 specialist orthopedic hospitals were retrospectively interrogated for all cases of intraosseous lipomas or SBCs with cross-sectional imaging follow-up for SBCs and precursor or follow-up imaging for intraosseous lipomas, in the time period from August 2007 to December 2016. For intraosseous lipoma cases, these were only included if change in imaging appearances was observed. RESULTS: There was no case of change in the appearance in intraosseous lipomas. Six cases of SBC with cross-sectional imaging follow-up were identified in one participating hospital and none in the other. The 6 cases were comprised of 4 male and 2 female patients. Two were located in the proximal humerus, one in the proximal tibia, and 3 in the os calcis. All cases demonstrated filling in of the cystic lesion with fat from the periphery, in 2 cases complete filling in, and in 4 cases partial fatty conversion. CONCLUSION: SBCs can heal with fatty conversion of the cystic cavity, with partly cystic remnants. It is proposed that at least part of the so-called intraosseous lipomas are healed simple bone cysts.

Stress Injuries of the Spine in Sports.

Spine sports stress injuries account for a significant amount of time loss at play in athletes, particularly if left unrecognized and allowed to progress. Spondylolysis makes up most of these stress injuries. This article focuses on spondylolysis, bringing together discussion from the literature on its pathomechanics and the different imaging modalities used in its diagnosis. Radiologists should be aware of the limitations and more importantly the roles of different imaging modalities in guiding and dictating the management of spondylolysis. Other stress-related injuries in the spine are also discussed including but not limited to pedicle fracture and apophyseal ring injury.

Consensus document for the diagnosis of peripheral bone infection in adults: a joint paper by the EANM, EBJIS, and ESR (with ESCMID endorsement).

INTRODUCTION: In adults with a suspicion of peripheral bone infection, evidence-based guidelines in choosing the most accurate diagnostic strategy are lacking. AIM AND METHODS: To provide an evidence-based, multidisciplinary consensus document on the diagnostic management of adult patients with PBIs, we performed a systematic review of relevant infectious, microbiological, orthopedic, radiological, and nuclear medicine literature. Delegates from four European societies (European Bone and Joint Infection Society, European Society of Microbiology and Infectious Diseases, European Society or Radiology, and European Association of Nuclear Medicine) defined clinical questions to be addressed, thoroughly reviewed the literature pertinent to each of the questions, and thereby evaluated the diagnostic accuracy of each diagnostic technique. Inclusion of the papers per statement was based on a PICO (Population/problem - Intervention/indicator - Comparator - Outcome) question following the strategy reported by the Oxford Centre for Evidence-based Medicine. For each statement, the level of evidence was graded according to the 2011 review of the Oxford Centre for Evidence-based Medicine. All approved statements were addressed taking into consideration the available diagnostic procedures, patient acceptance, tolerability, complications, and costs in Europe. Finally, a commonly agreed-upon diagnostic flowchart was developed.

Consensus document for the diagnosis of prosthetic joint infections: a joint paper by the EANM, EBJIS, and ESR (with ESCMID endorsement).

BACKGROUND: For the diagnosis of prosthetic joint infection, real evidence-based guidelines to aid clinicians in choosing the most accurate diagnostic strategy are lacking. AIM AND METHODS: To address this need, we performed a multidisciplinary systematic review of relevant nuclear medicine, radiological, orthopaedic, infectious, and microbiological literature to define the diagnostic accuracy of each diagnostic technique and to address and provide evidence-based answers on uniform statements for each topic that was found to be important to develop a commonly agreed upon diagnostic flowchart. RESULTS AND CONCLUSION: The approach used to prepare this set of multidisciplinary guidelines was to define statements of interest and follow the procedure indicated by the Oxford Centre for Evidence-based Medicine (OCEBM).

Correction to: Consensus document for the diagnosis of prosthetic joint infections: a joint paper by the EANM, EBJIS, and ESR (with ESCMID endorsement).

The authors regret to inform the readers that one of the author's name in the original publication of this article was spelled incorrectly as Victor Casar-Pullicino. The correct spelling is Victor N. Cassar-Pullicino and is now presented correctly in this article.

Diagnosis of peripheral bone and prosthetic joint infections: overview on the consensus documents by the EANM, EBJIS, and ESR (with ESCMID endorsement).

OBJECTIVES: Peripheral bone infection (PBI) and prosthetic joint infection (PJI) are two different infectious conditions of the musculoskeletal system. They have in common to be quite challenging to be diagnosed and no clear diagnostic flowchart has been established. Thus, a conjoined initiative on these two topics has been initiated by the European Society of Radiology (ESR), the European Association of Nuclear Medicine (EANM), the European Bone and Joint Infection Society (EBJIS), and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). The purpose of this work is to provide an overview on the two consensus documents on PBI and PJI that originated by the conjoined work of the ESR, EANM, and EBJIS (with ESCMID endorsement). METHODS AND RESULTS: After literature search, a list of 18 statements for PBI and 25 statements for PJI were drafted in consensus on the most debated diagnostic challenges on these two topics, with emphasis on imaging. CONCLUSIONS: Overall, white blood cell scintigraphy and magnetic resonance imaging have individually demonstrated the highest diagnostic performance over other imaging modalities for the diagnosis of PBI and PJI. However, the choice of which advanced diagnostic modality to use first depends on several factors, such as the benefit for the patient, local experience of imaging specialists, costs, and availability. Since robust, comparative studies among most tests do not exist, the proposed flowcharts are based not only on existing literature but also on the opinion of multiple experts involved on these topics. KEY POINTS: • For peripheral bone infection and prosthetic joint infection, white blood cell and magnetic resonance imaging have individually demonstrated the highest diagnostic performance over other imaging modalities. • Two evidence- and expert-based diagnostic flowcharts involving variable combination of laboratory tests, biopsy methods, and radiological and nuclear medicine imaging modalities are proposed by a multi-society expert panel. • Clinical application of these flowcharts depends on several factors, such as the benefit for the patient, local experience, costs, and availability.

Multiple long bone cysts revealed by MRI in trichorhinophalangeal syndrome type II predisposing to pathological fractures.

Trichorhinophalangeal syndrome type II is a rare genetic disorder with the few published case reports mainly reporting the radiographic skeletal manifestations. There are no published imaging reports of long bone cysts involving multiple bones in this condition. We report a unique case of bone cysts involving multiple long bones detected with MRI in a patient with trichorhinophalangeal syndrome type II complicated by a subsequent pathological fracture. It is possible that the bone cysts are a previously undescribed feature of this syndrome; however, the evidence is insufficient to establish a definite association. Chromosomal abnormality identified in this patient is consistent with trichorhinophalangeal syndrome type II with no unusual features. Although the nature of these bone cysts is unclear, they are one of the causes of the known increased fracture risk observed in this syndrome.

Imaging of Paget's disease of bone.

Paget's disease of bone is a disorder of bone remodelling, leading to changes in the architecture and overall appearance of the bone. The disorder may be monostotic or polyostotic and affect any bone in the body, although most commonly it involves the spine, pelvis, skull and femur. This article explores the different imaging modalities used in the assessment of Paget's disease of bone in its different phases. The relative merits of each imaging modality is discussed with illustrative examples, in particular with respect to radiographs, nuclear medicine bone scan, computed tomography (CT) and magnetic resonance imaging (MRI).

Paget Disease of Bone.

Paget disease (PD) is a common disease of bone associated with abnormal bone turnover that in turn is due to an imbalance between osteoclastic and osteoblastic activity. There is good evidence that PD is reducing in incidence, prevalence, and severity. The disease is most often asymptomatic and is usually detected incidentally on imaging examinations performed for other reasons. The features of PD are relatively specific on radiographs and computed tomography. However, the appearances on magnetic resonance imaging are subtle and nonspecific, although it has become the initial imaging choice for several clinical indications including back pain, neurologic dysfunction, and knee pain. It is therefore important to be familiar with the various imaging appearances of this relatively common disease in an increasingly aging population. In this article we discuss the various imaging appearances of PD and its complications.

Neuropathic osteoarthropathy with and without superimposed osteomyelitis in patients with a diabetic foot.

Soft tissue and bone infection involving the foot is one of the most common long-term complications of diabetes mellitus, implying a serious impairment in quality of life for patients in the advanced stages of the disease. Neuropathic osteoarthropathy often coexists and differentiating between these two entities is commonly challenging, but crucial, as the management may differ substantially. The importance of correct diagnosis cannot be understated and effective management requires a multidisciplinary approach owing to the complicated nature of therapy in such patients. A missed diagnosis has a high likelihood of major morbidity for the patient, including limb amputation, and over-diagnosis results in a great socioeconomic challenge for healthcare systems, the over-utilization of healthcare resources, and the unwise use of antibiotics. Diagnosis is largely based on clinical signs supplemented by various imaging modalities such as radiography, MR imaging, and hybrid imaging techniques such as F-18 fluorodeoxyglucose-positron emission tomography. In the interests of the management of diabetic foot complications, this review article is aimed on the one hand at providing radiologists with important clinical knowledge, and on the other hand to equip clinicians with relevant radiological semiotics.

The SAPHO syndrome revisited with an emphasis on spinal manifestations.

The synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome includes a group of chronic, relapsing, inflammatory musculoskeletal disorders with similar manifestations, in particular synovitis, hyperostosis, and osteitis, which may or may not be associated with neutrophilic skin eruptions such as palmoplantar pustulosis and acne conglobata. The syndrome occurs at any age, can involve any skeletal site, and its imaging appearances are variable, depending on the stage/age of the lesion and imaging method. The diagnosis is difficult if there is no skin disease. Awareness of the imaging appearances, especially in the spine, may help the radiologist in avoiding misdiagnosis (e.g., infection, tumor) and unnecessary invasive procedures, while facilitating early diagnosis and selection of an effective treatment. In this article, we provide an overview of the radiological appearances of SAPHO syndrome, focusing on the magnetic resonance imaging findings of vertebral involvement, and present relevant clinical and pathological features that assist early diagnosis.

Radiofrequency thermo-ablation of PVNS in the knee: initial results.

INTRODUCTION: Pigmented villonodular synovitis (PVNS) is normally treated by arthroscopic or open surgical excision. We present our initial experience with radiofrequency thermo-ablation (RF ablation) of PVNS located in an inaccessible location in the knee. MATERIALS: Review of all patients with histologically proven PVNS treated with RF ablation and with at least 2-year follow-up. RESULTS: Three patients met inclusion criteria and were treated with RF ablation. Two of the patients were treated successfully by one ablation procedure. One of the three patients had a recurrence which was also treated successfully by repeat RF ablation. There were no complications and all patients returned to their previous occupations following RF ablation. CONCLUSION: In this study we demonstrated the feasibility of performing RF ablation to treat PVNS in relatively inaccessible locations with curative intent. We have also discussed various post-ablation imaging appearances which can confound the assessment for residual/recurrent disease.

Prevalence of extraforaminal nerve root compression below lumbosacral transitional vertebrae.

OBJECTIVE: Although pathology at the first mobile segment above a lumbosacral transitional vertebra (LSTV) is a known source of spinal symptoms, nerve root compression below an LSTV, has only sporadically been reported. Our objective was to assess the prevalence of nerve root entrapment below an LSTV, review the causes of entrapment, and correlate with presenting symptoms. MATERIALS AND METHODS: A retrospective review of MR and CT examinations of the lumbar spine was performed over a 5.5-year period in which the words "transitional vertebra" were mentioned in the report. Nerve root compression below an LSTV was assessed as well as the subtype of transitional vertebra. Correlation with clinical symptoms at referral was made. MR and CT examinations were also reviewed to exclude any other cause of symptoms above the LSTV. RESULTS: One hundred seventy-four patients were included in the study. Neural compression by new bone formation below an LSTV was demonstrated in 23 patients (13%). In all of these patients, there was a pseudarthrosis present on the side of compression due to partial sacralization with incomplete fusion. In three of these patients (13%), there was symptomatic correlation with no other cause of radiculopathy demonstrated. A further 13 patients (57%) had correlating symptoms that may in part be attributable to compression below an LSTV. CONCLUSIONS: Nerve root compression below an LSTV occurs with a prevalence of 13% and can be symptomatic in up to 70% of these patients. This region should therefore be carefully assessed in all symptomatic patients with an LSTV.

Image guided radiofrequency thermo-ablation therapy of chondroblastomas: should it replace surgery?

OBJECTIVE: To assess the safety and effectiveness of image-guided radiofrequency ablation (RF ablation) in the treatment of chondroblastomas as an alternative to surgery. MATERIALS AND METHODS: Twelve patients with histologically proven chondroblastoma at our institution from 2003 to date. We reviewed the indications, recurrences and complications in patients who underwent RF ablation. RESULTS: Twelve patients were diagnosed with chondroblastoma. Out of these, 8 patients (6 male, 2 female, mean age 17 years) with chondroblastoma (mean size 2.7 cm) underwent RF ablation. Multitine expandable electrodes were used in all patients. The number of probe positions needed varied from 1 to 4 and lesions were ablated at 90 °C for 5 min at each probe position. The tumours were successfully treated and all patients became asymptomatic. There were no recurrences. There were 2 patients with knee complications, 1 with minor asymptomatic infraction of the subchondral bone and a second patient with osteonecrosis/chondrolysis. CONCLUSION: Radiofrequency ablation appears to be a safe and effective alternative to surgical treatment with a low risk of recurrence and complications for most chondroblastomas. RF ablation is probably superior to surgery when chondroblastomas are small (less than 2.5 cm) with an intact bony margin with subchondral bone and in areas of difficult surgical access.

Subchondral impaction fractures of the non-weight-bearing portion of the lateral femoral condyle.

OBJECTIVE: To document the first report of intra-articular, non-weight-bearing, impaction fractures of the lateral femoral condyle. MATERIALS & METHODS: Institutional Review Board and Regional Ethics Committee approval for this study was obtained and patient informed consent deemed unnecessary. We prospectively documented all potential cases of non-weight-bearing posterior subchondral impaction fractures of the femoral condyles diagnosed on magnetic resonance imaging (MRI) of the knee performed at our institution between January 2006 and December 2011. The cases were reviewed and discussed by three experienced musculoskeletal radiologists and only cases satisfying pre-defined MRI criteria were included. RESULTS: Sixteen cases of intra-articular impaction fractures in a posterior, non-weight-bearing area of the lateral femoral condyle were diagnosed in patients with a mean age of 40. Eight were associated with recreational sports activities and 4 with repeated kneeling. There were no fractures documented in the non-weight-bearing aspect of the medial femoral condyles. Proposed underlying mechanisms for development of this type of fracture are presented. CONCLUSION: Awareness, along with a high level of suspicion, that non-specific knee pain, especially in patients involved in athletic activities, could be due to intra-articular impaction fractures of the non-weight-bearing posterior aspect of the lateral femoral condyle is essential and MRI is the mainstay of diagnosis.