Search PubMed⌕ Search

Biomedical subjects

F L Chan

Publications and source records attributed to F L Chan.

At least 127 records · Page 7Linked to original sources

Portal thrombosis complicating appendicitis: ultrasound detection and hepatic computed tomography lobar attenuation alteration.

Lobar attenuation difference of liver on computed tomography was seen in a case of portal pyemia complicating perforated appendicitis. Left portal vein thrombus was detected first by ultrasound and subsequently confirmed by computed tomography. The left lobe of the liver showed greater contrast enhancement during the dynamic computed tomography study. The possible cause of this lobar attenuation difference is discussed.

Adult↗

Lacunar syndromes due to brainstem infarct and haemorrhage.

Nine patients with brainstem infarct and two with brainstem haemorrhage presented with pure motor stroke, pure supranuclear facial palsy, sensorimotor stroke or ataxic hemiparesis. Despite the clinical similarity with hemispheric lacunes, brainstem infarcts causing lacunar syndromes probably have a greater tendency to progress. Small brainstem haemorrhages should also be considered as a cause of lacunar syndromes and the difficulty in differentiating them from small infarcts without CT is emphasised.

Aged↗

Spinal pseudarthrosis in ankylosing spondylitis. Clinicopathological correlation and the results of anterior spinal fusion.

We reviewed 40 extensive destructive vertebral lesions in 35 patients with established ankylosing spondylitis. Of these, 31 had presented with localised pain while three had a neurological deficit. The radiographs suggested ununited fractures through either ankylosed discs (37) or vertebral bodies (3). Corresponding fractures were seen in the posterior column in 34 cases. Sixteen patients with 18 lesions underwent anterior spinal fusion, and pseudarthrosis was consistently proven by histopathology. Two pseudarthroses healed in conservatively treated patients. Thirteen of the operated patients were followed for an average of 7 years 7 months. There were two cases of non-union and one required an additional posterior fusion; in the remainder fusion was sound.

Adult↗

Spinal pseudarthrosis complicating ankylosing spondylitis: comparison of CT and conventional tomography.

Pseudarthrosis, a functional false joint, is an important mechanical complication of advanced ankylosing spondylitis. For correct determination of prognosis and therapy, the presence and extent of the abnormality must be assessed accurately. CT findings in 18 patients with 22 pseudarthroses were compared with the results of conventional tomography. The condition was confirmed by surgery in nine patients (50%). CT scans clearly characterized the pseudarthrosis, providing data not provided by conventional tomography in 17 (77%) of the 22 lesions. CT showed irregular diskovertebral osteolysis with reactive sclerosis and more frequently detected the vacuum phenomenon and paraspinal swellings. In all cases, CT showed either a fracture of mobile facet joints in the posterior elements and allowed clear differentiation between the two. In four cases, such differentiation was impossible on conventional tomograms. Associated spinal stenosis was suspected on conventional tomograms in three lesions, but it was shown clearly by CT in 10 lesions. Our results suggest that CT offers considerable advantages over conventional tomography in the investigation of spinal pseudarthrosis complicating ankylosing spondylitis.

Adult↗

Diagnosis and evaluation of esophageal atresia by direct sagittal CT.

Direct sagittal CT is possible in newborns because of their small body-size. With this noninvasive investigation, we were able to establish a correct diagnosis in two neonates with esophageal atresia. Moreover, the demonstration of the air-filled proximal pouch and distal tracheoesophageal fistula along their whole lengths allowed exclusion of the possibility of a proximal pouch fistula and gave knowledge of the exact distance of the two segments of the esophagus needed to be bridged to allow anastomosis, thus providing additional valuable information for the surgeon preoperatively.

Esophageal Atresia↗

Sacrococcygeal teratoma: computed tomography evaluation.

Axial computed tomography, as well as direct sagittal computed tomography in some cases, was used to evaluate five cases of sacrococcygeal tumors, and the findings are presented. Computed tomography greatly assisted in making a correct preoperative diagnosis and in delineating the extent of the tumors. Direct sagittal scans readily staged these tumors, whereas axial scans revealed extension in the transverse plane, especially for intraspinal extension.

Child, Preschool↗

Claude's syndrome: clinical and computed tomography correlations.

A patient with Claude's syndrome (ipsilateral fascicular third nerve palsy with contralateral ataxia) in whom computed tomography demonstrated a discrete infarct in the paramedian rostral mesencephalic tegmentum is reported. The vascular supply of the rostral mesencephalon is discussed.

Aged↗

Recurrent pyogenic cholangitis: ultrasound evaluation compared with endoscopic retrograde cholangiopancreatography.

Fifty cases of recurrent pyogenic cholangitis among Chinese in Hong Kong were studied by ultrasound and compared with endoscopic retrograde cholangiopancreatography. The sensitivity of ultrasound detection of both dilated intrahepatic biliary ducts and intrahepatic calculi is 67% as compared with endoscopic retrograde cholangiopancreatography. A negative study, therefore, does not rule out the presence of such pathological features. A dilated common duct is present in virtually every case of recurrent pyogenic cholangitis and ultrasound is very accurate in its detection. Furthermore, ultrasound is able to provide additional information which can be missed with endoscopic retrograde cholangiopancreatography. Prominent periportal echogenicity, concomitant abscesses and tumours are examples in this series. Such findings bear significance on the management of patients with recurrent pyogenic cholangitis.

Cholangiopancreatography, Endoscopic Retrograde↗

Direct sagittal CT scan: a new diagnostic approach for surgical neonates.

Because of their small body size, neonates can be placed in the plane of the CT scanner gantry (aperture diameter 70 cm) instead of across it. This direct sagittal scanning technique allows accurate delineation of surgical lesions, particularly midline ones, unobtainable with conventional axial imaging. In addition, the sagittal image provides a perspective of anatomic arrangement more familiar to the surgeon than that provided by axial sections and therefore allows for easier interpretation. In imperforate anus, sagittal CT identifies the blind rectal end by the meconium tissue interphase and therefore avoids the pitfalls of invertogram, which depends on the bowel gas pattern for interpretation. With this new approach, we correctly classified six cases of imperforate anus into high types (3) and low types (3), visualized the associated fistula and had knowledge of the exact distance of the blind rectal end from the skin level preoperatively. In tracheoesophageal fistula (2), sagittal CT demonstrated the air-filled blind pouch and fistula to allow preoperative classification and assessment of the gap distance. In sacrococcygeal teratoma (3) and laryngeal cyst (1), its use allowed an accurate assessment of possible extension of the lesion into neighboring structures. Our experience with direct sagittal CT scan therefore suggests that this new and noninvasive technique is a useful adjunct in the management of a variety of common neonatal surgical problems.

Anus, Imperforate↗

High dose ketoconazole in the treatment of cerebral aspergilloma.

A 32-year-old Chinese woman with bilateral occipital aspergilloma was treated successfully with high dose ketoconazole (1200 mg/day) for six months in conjunction with amphotericin B and 5-fluorocytosine. No unacceptable side effects occurred. The use of high dose ketoconazole could be considered in CNS aspergillosis unresponsive to conventional anti-fungal therapy.

Adult↗

When is sensorimotor stroke a lacunar syndrome?

Forty five patients with clear sensorium and no neurological deficits other than unilateral motor and sensory impairment underwent computed tomography (CT). Twenty patients had sensorimotor stroke with impairment of all sensory modalities (type 1). Eight had only impairment of nociceptive sensation (type 2) and 15 had only proprioceptive impairment (type 3). Two patients had sensory impairment in one limb only (type 4). Lacunes were found in patients in the first three groups. However, 80% of those who had hemiparesis and incomplete sensory loss were found to have a lacune or normal CT scan whilst only 33% of those with complete motor or sensory impairment had lacunes. It is proposed that sensorimotor stroke as a lacunar syndrome be best restricted to those with only mild to moderate hemiparesis and sensory impairment in both upper and lower limbs. The degree and extent of sensory and motor involvement may vary, however, possibly dependent on whether the thalamo-geniculate, anterior choroidal or lateral lenticulostriate artery is affected.

Aged↗