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Biomedical subjects

A M Davies

Publications and source records attributed to A M Davies.

At least 19 recordsLinked to original sources
PubMed2006

Intra-osseous pseudoaneurysm following curettage of an aneurysmal bone cyst.

BACKGROUND: Pseudoaneurysms secondary to bone tumours are rare and most of the reported cases are related to osteochondromas, either due to direct pressure or following surgery. Aneurysmal bone cysts are relatively common bony lesions usually treated by curettage. DISCUSSION: We describe an unusual case of pseudoaneurysm of the anterior tibial artery complicating curettage of an aneurysmal bone cyst which presented as a rapidly enlarging mass clinically thought to be rapid recurrence of the tumour. This was successfully treated by embolisation.

Aneurysm, False↗
PubMed2006

Hibernoma--correlation of histopathology and magnetic-resonance-imaging features in 10 cases.

UNLABELLED: OBJECTIVE, DESIGN AND PATIENTS: Hibernoma is an uncommon, slow-growing, benign soft-tissue tumour resembling brown adipose tissue. The histological appearances are well-documented, but there are relatively few descriptions of the magnetic resonance (MR) imaging features. We report a retrospective comparison of the histological and MR appearances of ten hibernomas of the extremities, classified histologically into lipoma-like [<70% multivacuolated adipocytes (MVAs)] and non-lipoma-like hibernomas (>70% MVAs). RESULTS: The lipoma-like hibernomas measured 4-27 cm in maximum size. All were well-defined on MR imaging and histology except for one subcutaneous lesion that blended in with surrounding fat histologically. All lesions were isointense with subcutaneous fat on T1- and T2-weighting apart from one lesion that was predominantly slightly hypointense on T1-weighting and predominantly slightly hyperintense on T2-weighting and STIR. Two slightly inhomogeneous lesions contained thin (<5 mm thickness) tortuous vessels. One patient received intravenous contrast, but the lesion did not enhance. The six non-lipoma-like hibernomas measured 2.5-15.5 cm in maximum size and all were unencapsulated. Three were well-defined and three partly ill-defined on MR imaging. There were no significant differences in the MR characteristics of the non-lipoma-like variants. On T1-weighting, the non-lipoma-like hibernomas that contained >90% MVAs were predominantly slightly hypointense to subcutaneous fat. One lesion was isointense with subcutaneous fat, but this lesion only contained from 80-90% MVAs. All non-lipoma-like lesions were slightly hyperintense on STIR but so too were two of the four lipoma-like lesions. Four of the six non-lipoma-like lesions showed marked or moderate inhomogeneity due to thick septa and prominent vessels. Of the two cases that received intravenous contrast, both showed enhancement corresponding to regions of >90% MVAs or prominent vessels within fibrous septa. CONCLUSIONS: MR imaging has shown some distinguishing features between lipoma-like and non-lipoma-like hibernomas. Lipoma-like hibernomas are usually isointense with subcutaneous fat on T1-weighting, are either homogeneous or slightly inhomogeneous and may contain thin tortuous vascular structures. Non-lipoma-like hibernomas are pre-dominantly slightly hypointense to subcutaneous fat on T1-weighting, often display marked or moderate inhomogeneity with prominent septa and vessels and enhancement is typical. The appearances of non-lipoma-like hibernomas are not diagnostic and may be mimicked by lipoma variants and by well-differentiated liposarcoma or atypical lipoma.

Adult↗
PubMed2006

Imaging of infectious spinal disorders in children and adults.

The aim of this review article is to outline the imaging of infectious disorders of the spine in adults and children. The clinical presentation, potential routes of infection and the pathogens commonly identified are discussed. The value of different imaging modalities in the diagnosis of spinal infection is presented including radiographic, CT, MR imaging and Nuclear Medicine including PET. The use of image guided techniques for diagnosis and subsequent treatment is briefly covered. The major differential diagnoses of infectious disorders of the spine are identified and contrasted with the typical findings in infection. The use of follow up imaging is evaluated.

Adult↗
PubMed2006

Benign primary tumours of the ribs.

Benign primary tumours of the ribs are rare and may be identified during the investigation of a clinically suspected abnormality or as an incidental finding. This review describes the spectrum of benign tumours that can involve the rib and illustrates the radiographic, computed tomography (CT) and magnetic resonance (MR) imaging appearances that may facilitate diagnosis.

Bone Cysts, Aneurysmal↗
PubMed2006

Ewing's sarcoma of bone: the detection of specific transcripts in a large, consecutive series of formalin-fixed, decalcified, paraffin-embedded tissue samples using the reverse transcriptase-polymerase chain reaction.

AIMS: (i) To report on the routine use of the reverse transcriptase-polymerase chain reaction (RT-PCR) technique on decalcified or non-decalcified, formalin-fixed, paraffin-embedded tissue (FFPET) for translocation detection, with particular emphasis on improved RNA extraction methodology and the use of PCR primers designed to generate small amplicons. (ii) To report on the relative incidences of translocation types and transcript variants in a large, single institution series of Ewing's sarcoma of bone. METHODS AND RESULTS: Using RT-PCR to detect specific transcript variants, we analysed FFPET from 54 consecutive cases of Ewing's sarcoma of bone. We used 'gold standard' detection methods on corresponding fresh and fresh frozen tissue to validate the technique. We have demonstrated the effective use of RT-PCR on decalcified and non-decalcified FFPET samples for sarcoma-specific translocation detection (96% sensitivity, 100% specificity). Tissue decalcification did not affect the detection rate. The relative incidence of Ewing's sarcoma-specific translocation types and transcript variants was entirely consistent with previously published data. CONCLUSIONS: With equal effectiveness, RT-PCR can be applied to both acid decalcified and non-decalcified FFPET for (Ewing's sarcoma) translocation detection and the technique can be introduced into routine practice in histopathology departments.

Adolescent↗
PubMed2005

The effect of X-rays on bone: a pictorial review.

The deleterious effects of X-rays on bone have been recognised for almost a century and continue to be seen today because of improved survival in patients treated for malignancy with radiotherapy with or without other treatments. In this pictorial review we present the imaging features of radiation damage to bone highlighting the differences seen in the immature skeleton and post-skeletal fusion. In the former, damage is greatest to the physis resulting in growth disturbances. In the mature skeleton there is a spectrum of changes from mild osteopenia, through disordered attempts at healing with varying degrees of sclerosis, radionecrosis which may lead to acute fractures following minimal trauma and insufficiency fractures both with refractory healing to the dreaded complication of sarcomatous transformation. The imaging appearances are illustrated and the features that help distinguish malignant change from other complications stressed.

Bone Diseases, Developmental↗
PubMed2005

Giant-cell tumours of bone of the hand and wrist: a review of imaging findings and differential diagnoses.

Giant-cell tumour of bone (GCTOB) is a benign, locally aggressive, primary bone tumour. Involvement of the distal radius accounts for between 10 and 12% of cases of GCTOB, with the bones of the hand and wrist being rarely affected. GCTOB most commonly affects skeletally mature patients between the ages of 20 and 40 years, with the peak incidence being in the third decade. Women are affected slightly more commonly than men. GCTOB involving the bones of the hand most commonly occurs in a central location, which differs from the usual eccentric location seen in GCTOB at other sites. The radiographic features of GCTOB in the hand and wrist are presented. The role of bone scintigraphy, computed tomography and magnetic resonance imaging is discussed. Evaluation of the postoperative patient is also addressed, including the role of dynamic contrast-enhanced magnetic resonance imaging. A comprehensive review of the potential differential diagnoses that should be considered when GCTOB is suspected in the hand and wrist is also presented.

Bone Neoplasms↗
PubMed2005

Intramedullary and extramedullary fat globules on magnetic resonance imaging as a diagnostic sign for osteomyelitis.

We retrospectively studied the frequency of persistent foci of fat signal on magnetic resonance (MR) imaging in osteomyelitis to assess its frequency, cause and diagnostic value. The radiographs and MR scans of 100 patients with a final diagnosis of osteomyelitis referred to a specialist orthopaedic oncology service with the presumptive diagnosis of a bone tumour were reviewed. The MR signal and morphological characteristics were recorded with particular attention to the presence of persistent fat signal within the infected area, which was classified as diffuse or focal. Seventeen cases were classified on radiographic grounds as acute, 63 as subacute and 20 as chronic osteomyelitis. In the acute group 12 (70%) showed replacement of the marrow with fluid containing residual fatty signal, diffuse in seven and focal in five cases. Two cases showed predominantly fatty marrow with very early marrow oedema and three cases (18%) showed replacement of marrow fat with fluid and no residual fatty foci. None of the subacute group showed foci of fatty signal and two cases of inactive sclerosing osyeomyelitis in the chronic group showed restoration of normal marrow. Persistent fatty signal within the bone as well as soft tissues on MR imaging is a frequent finding in acute osteomyelitis. Radiological-pathological correlation suggests that the increasing intramedullary pressure leads to septic necrosis with death of the lipocytes and release of free fatty globules. This characteristic, but not pathognomonic, MR finding supports the diagnosis of osteomyelitis and may help to exclude the presence of a tumour.

Adipose Tissue↗
PubMed2005

Surface lesions of the bones of the hand.

Surface lesions involving the bones of the hand are uncommon. This pictorial review illustrates the spectrum of conditions including benign primary bone tumours, malignant primary bone tumours and non-neoplastic disorders. The review focuses on the radiographic appearances of these lesions and other techniques such as CT and MR imaging that may suggest a specific diagnosis.

Bone Neoplasms↗
PubMed2005

Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage.

We undertook this retrospective study to determine the rate of recurrence and functional outcome after intralesional curettage for chondroblastoma of bone. The factors associated with aggressive behaviour of the tumour were also analysed. We reviewed 53 patients with histologically-proven chondroblastoma who were treated by intralesional curettage in our unit between 1974 and 2000. They were followed up for at least two years to a maximum of 27 years. Seven (13.2%) had a histologically-proven local recurrence. Three underwent a second intralesional curettage and had no further recurrence. Two had endoprosthetic replacement of the proximal humerus and two underwent below-knee amputation after aggressive local recurrence. One patient had the rare malignant metastatic chondroblastoma and eventually died. The mean Musculoskeletal Tumour Society functional score of the survivors was 94.2%. We conclude that meticulous intralesional curettage alone can achieve low rates of local recurrence and excellent long-term function.

Adolescent↗
PubMed2004

Calcific myonecrosis: a report of ten new cases with an emphasis on MR imaging.

The aim of this study is to report the typical radiographic and MR imaging features of calcific myonecrosis, which help to distinguish this rare entity from other causes of a calcifying calf mass. Ten patients with a final diagnosis of calcific myonecrosis were referred to a specialist orthopaedic oncology service in a 5-year period with the presumptive diagnosis of malignancy based on recent clinical presentation and imaging findings. Radiographs were available for retrospective review in all ten cases and MR imaging in six. All patients presented with a slow-growing painless calf mass. All gave a history of major trauma to the lower leg many years before, but in only two cases did the referring clinician query whether trauma might be a contributory factor. Radiographs showed well-defined fusiform mineralised masses up to 25 cm in length arising within the calf. The calcification was consistently peripheral and plaque-like. Ossification was not present. MR imaging showed the anterior compartment to be involved in four cases and all compartments in two. T1- and T2-weighted images showed peripheral low signal intensity, more prominent on the T2-weighted images, because of the peripheral mineralization. The contents of the masses were variable on T1-weighted images depending on the differing amounts of blood breakdown products and were heterogeneous on T2-weighted images. The latter may be explained by a combination of the mineralisation and T2 shortening due to blood breakdown products. A gadolinium chelate, administered in two cases, failed to show any appreciable enhancement. Calcific myonecrosis has characteristic clinical, radiographic and MR features that should make the condition easy to recognise. Despite its rarity, it should be included in the differential diagnosis of focal mineralisation of the calf.

Adult↗
PubMed2004

Differential diagnosis of tumours and tumour-like lesions of the infrapatellar (Hoffa's) fat pad: pictorial review with an emphasis on MR imaging.

A variety of intrinsic and extrinsic tumours and tumour-like conditions may affect the infrapatellar (Hoffa's) fat pad (IFP). MR imaging is the technique of choice in evaluating these conditions, but correlation with radiographs is important to identify those lesions producing mineralization. This pictorial review illustrates the spectrum of mass-like lesions that can affect the IFP, emphasizing the radiographic and MR findings that suggest a specific diagnosis.

Bone Neoplasms↗
PubMed2004

The penumbra sign in subacute osteomyelitis.

The penumbra sign is a characteristic magnetic resonance (MR) feature of subacute osteomyelitis. It can be identified on unenhanced T1-weighted spin echo images as a discrete peripheral zone of marginally higher signal intensity than the central bony abscess cavity and the surrounding lower signal intensity of the reactive new bone and oedema.

Acute Disease↗
PubMed2004

Imaging features of intraosseous ganglia: a report of 45 cases.

The aim of this study is to report the spectrum of imaging findings of intraosseous ganglia (IG) with particular emphasis on the radiographic and magnetic resonance (MR) features. Forty-five patients with a final diagnosis of IG were referred to a specialist orthopaedic oncology service with the presumptive diagnosis of either a primary or secondary bone tumour. The diagnosis was established by histology in 25 cases. In the remainder, the imaging features were considered characteristic and the lesion was stable on follow-up radiographic examination. Radiographs were available for retrospective review in all cases and MR imaging in 29. There was a minor male preponderance with a wide adult age range. Three quarters were found in relation to the weight-bearing long bones of the lower limb, particularly round the knee. On radiographs all were juxta-articular and osteolytic; 74% were eccentric in location, 80% had a sclerotic endosteal margin and 60% of cases showed a degree of trabeculation. Periosteal new bone formation and matrix mineralization were not present. Of the 29 cases that underwent MR imaging, 66% were multiloculated. On T1-weighted images the IG contents were isointense or mildly hypointense in 90% cases. Forty-one per cent of the cases showed a slightly hyperintense rim lining that enhanced with a gadolinium chelate. Thirty-eight per cent were associated with soft tissue extension and 17% with a defect of the adjacent articular cortex. Fifty-five per cent showed surrounding marrow oedema on T2-weighted or STIR images and two cases (7%) a fluid-fluid level prior to any surgical intervention. The authors contend that it is semantics to differentiate between an IG and a degenerate subchondral cyst as, while the initial pathogenesis may vary, the histological endpoint is identical, as are the imaging features apart from the degree of associated degenerative joint disease. IGs, particularly when large, may be mistaken for a bone tumour. Correlation of the typical radiographic and MR imaging features will indicate the correct diagnosis and obviate the need for biopsy.

Adult↗
PubMed2004

Calcific haemorrhagic bursitis anterior to the knee mimicking a soft tissue sarcoma: report of two cases.

We describe the radiological and pathological findings of two cases of calcific haemorrhagic bursitis, one involving the superficial infrapatellar bursa and the other the prepatellar bursa. It was the presence of dystrophic calcification within the lesion that suggested a mineralizing soft tissue sarcoma such as synovial sarcoma. As the radiographic and MR features of the two conditions can be similar but the appropriate management very different, rare calcifying haemorrhagic bursitis needs to be included in the differential diagnosis of masses adjacent to the knee joint showing calcification.

Aged↗
PubMed2004

The MR imaging appearances and natural history of seromas following excision of soft tissue tumours.

Fluid collections (seromas) may accumulate at the site of surgery following excision of musculoskeletal soft tissue tumours. The aim of this retrospective study was to review the magnetic resonance (MR) imaging features of postoperative seromas identifying changes over time on follow-up scans. A total of 170 MR scans from 80 patients were reviewed showing one or more seromas. All patients had undergone previous surgery for a musculoskeletal soft tissue tumour. The typical MR appearances of a seroma were shown to be a well-defined oval or rounded (54%) soft tissue mass, arising at the site of previous surgery, with a thin, dark pseudocapsule, surrounding soft tissue oedema (80%), homogeneous contents that are hypointense (relative to adjacent muscle) on T1-weighted images (74%) and hyperintense on T2-weighted and STIR images (79%). Approximately one-quarter of cases revealed atypical features including hyperintense contents on T1-weighted (26%) and/or heterogeneous contents on T2-weighted images (21%), reflecting the breakdown of blood products and organization of the fluid collection. A distinctive fine feathery pattern arising from the inner surface of the seroma or from septations was identified in 10% of cases. In those patients who underwent one or more follow-up scans, the volume of the seromas decreased in 66% cases, remained unchanged in 15% and increased in 19%. Seromas are not an uncommon finding (<10% of cases) following surgery for a soft tissue tumour. The majority of cases show the typical MR features of a fluid collection. The pitfalls in differentiating an atypical seroma from a recurrent soft tissue sarcoma are discussed.

Adolescent↗