Oncogenic osteomalacia associated with an occult phosphaturic mesenchymal tumour: clinico-radiologico-pathological correlation and ultrastructural studies.

A middle-aged man presented with bone pain at multiple sites due to tumour-induced osteomalacia. The underlying occult phosphaturic mesenchymal tumour was identified by octreotide scan 5 years after presentation and confirmed by computed tomography. Tumour resection resulted in normalisation of blood chemistry and bone densitometry. Clinico-radiologico-pathological correlation and ultrastructural studies of the tumour threw light on the pathogenesis and pathophysiology of this rare disease.

Duplex ultrasonography after total hip or knee arthroplasty.

We prospectively studied all patients admitted for total hip (THR) or knee (TKR) arthroplasty from July 2000 to February 2001. No pharmacological anticoagulation was given. All patients received a standardized postoperative rehabilitation regimen. Forty-six patients with known risk factors for deep vein thrombosis (DVT) were excluded. Eighty patients were studied (22 THR, 58 TKR; 55 women, 25 men). Mean age was 68 (30-90) years. Duplex ultrasonography on both lower limbs was performed on days 5-7 postoperatively. Location and extent of any thrombus were documented. In patients with distal DVT, a follow-up scan was done on days 10-14. If proximal propagation was observed, patients received full anticoagulation. If no propagation was detected, the distal thrombus was considered stable and clinical observation was continued. In the THR group, 1/22 and in the TKR group 9/58 were found to have distal DVT. All were asymptomatic. On follow-up scanning, none showed proximal propagation. All patients were followed up for at least 18 months, and none showed postthrombotic symptoms. Isolated distal DVT in "low-risk" Chinese patients after THR or TKR is not uncommon. Clinically they are usually "silent." If routine perioperative pharmacologic antithrombotic prophylaxis is not practiced, monitoring with duplex ultrasonography may need to be considered.

Deep venous thrombosis after total hip or knee arthroplasty in a "low-risk" Chinese population.

Scarcely any information has been published on deep vein thrombosis (DVT) in Chinese patients after total hip arthroplasty (THA) or total knee arthroplasty (TKA). However, generally, no prophylaxis is given to patients who do not have conventional high-risk factors because they are believed to be at "low risk." We performed a prospective study on 80 such "low risk" patients undergoing THA or TKA (58 TKA and 22 THA) without prophylaxis and performed duplex ultrasonography on both lower limbs 6 to 8 days after surgery. A total of 22 patients (27.5%) showed ultrasonographic evidence of DVT. Eighteen (31%) TKAs and 4 (18.1%) THAs were complicated by DVT. Three patients showed bilateral involvement, all of whom underwent TKA. Two patients had symptomatic pulmonary embolism. The sensitivity and positive predictive value of the clinical examination was 27.2% and 31.6%, respectively. This study showed that patients who are labeled "low risk" for DVT actually had a significant risk and suggests that the current practice of providing prophylaxis to only patients deemed at "high risk" should be revised.

Dirofilariasis of breast: report of two cases diagnosed by fine-needle aspiration biopsy.

We report on 2 cases of dirofilariasis of the breast occurring in adult Chinese females residing in Hong Kong. The diagnosis was made by fine-needle aspiration biopsies. The direct smears contained numerous acute inflammatory cells, including eosinophils. A partially necrotic adult nematode of about 400-450 microm in diameter was identified in the cell-block sections of each case. The worm was characterized by a thick cuticle with longitudinal cuticular ridges and fine transverse surface striations, abundant somatic muscle, an intestine, and a reproductive tube or uterus. The morphologic features of this round worm were most compatible with those of Dirofilaria repens. While the clinical and radiologic findings of dirofilariasis of the breast are nonspecific and mimic those of breast neoplasms or inflammatory conditions, a definitive diagnosis is possible with fine-needle aspiration biopsy. A correct diagnosis of dirofilariasis may help to spare patients from unnecessary medical and surgical interventions.

Determining the lumbar vertebral segments on magnetic resonance imaging.

STUDY DESIGN: A study to test the ability of an additional cervicothoracic localizer scan to decrease interobserver discrepancy in the identification of vertebral segments in magnetic resonance imaging of the lumbar spine. OBJECTIVES: To investigate whether lumbar vertebral segments can be identified correctly from lumbosacral magnetic resonance localizer scans, the degree of interobserver discrepancy, and the value of an additional cervicothoracic localizer scan. SUMMARY OF BACKGROUND DATA: In magnetic resonance imaging of the lumbar spine, it may be difficult to identify transitional lumbosacral vertebral segments. METHODS: The sagittal and coronal lumbosacral localizer scans of 141 consecutive patients referred for magnetic resonance imaging of the lumbosacral spine were reviewed independently by two radiologists with the aim of locating the L5 vertebra. An additional sagittal cervicothoracic localizer scan also was performed in each case. The final study group consisted of 129 patients. The L5 vertebra was identified by counting caudally from C2 using the sagittal cervicothoracic and lumbosacral localizer scans. In the 54 most recently studied patients, cod liver oil capsule surface markers were placed near the thoracolumbar junction to quantify any marker shift between the two sagittal localizer scans. RESULTS: The lumbar segments could be identified consistently by counting caudally using cervicothoracic and lumbosacral localizer scans. Using sagittal lumbosacral localizer scans alone, the lumbar vertebral segments could be identified correctly in only 80.2% of patients. Coronal lumbosacral localizer scans produced similar results (82.2%). The accuracy fell to 77.9% when using a combination of both sagittal and coronal lumbosacral localizer scans. There was a 11.6% interobserver discordance in assessment of these levels. Lumbosacral transitional vertebrae were identified in 17 patients (13.2%), including 8 sacralized L5 and 9 lumbarized S1 vertebrae. Apparent surface-marker shift between cervicothoracic and lumbosacral localizer scans was insignificant, averaging only 1.9 mm (range, 0.0-5.6 mm). CONCLUSIONS: The addition of a cervicothoracic localizer scan in magnetic resonance imaging of the lumbosacral spine is highly recommended.

Lumbar spine magnetic resonance imaging: comparison between fast spin echo proton density and spin echo T1 axial scans.

Spin echo (SE) T1 axial scans are routinely obtained in magnetic resonance imaging of the lumbar spine in many centres. This study directly compared matched SE T1 and fast SE (FSE) proton density (PD) axial scans. Both SE T1 and FSE PD axial scans of the lumbar spine were obtained in 116 consecutive patients. The imaging parameters (field-of-view, slice thickness, interslice gap, number of excitations and matrix size) and scan levels were identical for each pair of sequences. At two selected levels, L4/5 and L5/S1, various structures were independently graded by two observers. In 232 lumbar levels analysed, the bone marrow, epidural fat, disc, extradural nerve root and facet joint were equally well seen on both sequences by both observers (combined mean grades of 2.93-2.99). The thecal sac was marginally better depicted on FSE PD than on SE T1 images, with mean grades of 2.96 and 2.88, respectively. The psoas muscle was adequately visualized for diagnostic purposes on both sequences (mean grades of 2.30-2.32). The cauda equina were better seen on FSE PD (mean grade 1.92) than on SE T1 (mean grade 1.00) images. In conclusion, FSE PD scans are comparable to and may potentially replace SE T1 axial MR scans of the lumbar spine.