Biomedical subjects

F L Chan

Publications and source records attributed to F L Chan.

148 records · Page 9Linked to original sources

PubMedDate not supplied

Nasopharyngeal carcinoma: CT evaluation of patterns of tumor spread.

In a prospective study using CT as the initial means of radiologic evaluation in 262 patients with proved nasopharyngeal carcinoma, the paranasopharyngeal space was found to be the most commonly involved region (84.4%), both uni- and bilaterally. Unilateral involvement was found in 44.3% of patients (116/262) and bilateral involvement in 40.1% (105/262). The other structures or regions that were involved, in decreasing order of frequency, were the sphenoid sinus (26.7%), nasal fossa (21.8%), and ethmoid sinus (18.3%). Erosion of the base of the skull and intracranial intracranial extension into the middle cranial fossa were common (31.3% and 12.2%, respectively). The primary tumor in the nasopharynx was found to be contiguous with metastatic upper cervical nodes through paranasopharyngeal extension of tumor in 35 patients (13.4%). A qualitative method to assess the degree of paranasopharyngeal extension is proposed. The extent of paranasopharyngeal extension so evaluated was correlated with other attributes of tumor extent (p = .0001), namely, nasal or oropharyngeal extension, which constitutes a T3-level tumor, and erosion of the base of the skull or orbit, which constitutes a T4-level tumor. The extent of paranasopharyngeal extension was also correlated with local control of the tumors (p = .0001). At a median follow-up of 27 months, only three (7.9%) of the 38 patients with no paranasopharyngeal extension had nasopharyngeal relapse, while 12 (11.2%) of the 107 and 17 (34.7%) of the 49 patients with types 1 and 2 paranasopharyngeal extension, respectively, had nasopharyngeal relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

PubMedDate not supplied

Spinal pseudarthrosis in ankylosing spondylitis.

Spinal pseudarthrosis is an important mechanical complication in longstanding ankylosing spondylitis. Thirty-five patients with 40 lesions were studied. Three lesions through vertebral bodies resulted from complete fractures. The rest occurred at interspaces, more common at the lower thoracic and upper lumbar segments. Double pseudarthrotic lesions were observed in 5 patients. Progressive osteolysis of the anterior elements was prominent, with variable sclerosis, osteophytes, vacuum phenomenon, subluxation and fragmentation. A posterior element weak link, as a bony break or facet joint non-fusion, was an essential component in every lesion, playing an initiating or perpetuating role in its pathogenesis. Mechanical derangement from trauma, severe round kyphosis, spondylodiscitis, hip disease, spinal operation and unusual activities may be contributing factors. Initial treatment is conservative, but 16 patients required operative stabilisation.

Adult↗

PubMedDate not supplied

Cerebral haemorrhage in a urban Chinese population.

A prospective study of Chinese patients aged 20-70 years reveals that at least 30.5% of all strokes are due to cerebral haemorrhage. Compared to previous studies in Caucasians, there is both a proportional and absolute increase in cerebral haemorrhage amongst all strokes, alert strokes, or those who presented with just a lacunar syndrome. The cause for this increase is unclear but genetic, dietary, and other environmental factors may be involved.

Adult↗

PubMedDate not supplied

Modern imaging in the evaluation of hepatolithiasis.

Hepatolithiasis is a primary disease of the biliary ducts, presenting with recurrent pyogenic cholangitis, complicated by parenchymal infection, obstructive cholangiopathy and subsequent parenchymal destruction. Cholangiocarcinoma is a rarer complication. Modern imaging aims at accurate delineation of biliary ducts and liver parenchyma. It directs planning of surgical or interventional treatment, and serves to guide these procedures. The characteristic features comprise varying combinations of ductal dilatation, intrahepatic/extrahepatic ductal stones, segmental ductal strictures and lobar/segmental atrophy; and in acute exacerbation parenchymal or ductal contrast enhancement, abscess and biliary obstruction. Ultrasonography is the preferred primary examination. Further imaging depends on the ultrasonography findings, the patient's symptomatology, the clinical problems and the intended mode of treatment. Contrast cholangiography is warranted preceding biliary intervention. Computed tomography evaluates ductal stones, extent of disease, acute parenchymal complications and prior to hepatic resection. Magnetic resonance imaging is less accessible, but obtains cross-sectional findings similar to computed tomography. It comprehensively evaluates the liver and portal venous system, for prognostic indication and contemplation of liver resection. For diagnostic purposes, magnetic resonance cholangiography promises to replace the more invasive contrast cholangiography. Therapeutic approaches tailored to the results of strategically applied imaging helps to improve the outcome of patients with hepatolithiasis.

Atrophy↗