John H M Chan

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Diffusion weighted MRI was performed on patients with acute vertebral body compression. The usefulness of the apparent diffusion coefficient (ADC) in differentiating between benign and malignant fractures was evaluated. A total of 49 acute vertebral body compression fractures were found in 32 patients. 25 fractures in 18 patients were due to osteoporosis,(More)
The objective of the study was to evaluate the capability and reliability of the magnetic resonance (MR) diffusion-weighted imaging (DWI) in differentiation between hydronephrosis and pyonephrosis. Single-shot echoplanar MR diffusion-weighted imaging was performed in 12 patients who had dilatation of the renal pelvis and calyces detected by ultrasonography(More)
The aim of this study was to investigate the signal characteristics of the abscess wall and tumor wall on diffusion-weighted and perfusion-weighted images and thus to evaluate the feasibility of using combined MR diffusion and perfusion imaging to differentiate pyogenic cerebral abscess from infected brain tumor. The tumor wall of various types of cystic or(More)
We report a case of a 54-year-old man who had documented traumatic acute subdural hematoma. He suffered from a transient episode of confusion and a follow-up CT scan of brain 6 h after the initial scan showed resolution and redistribution of the subdural hematoma. In this case report, we review the literature for the underlying pathophysiology of this(More)
Increased signal intensity on magnetic resonance (MR) imaging of tendons arising from the magic angle phenomenon is well recognized. This study aimed to evaluate the effect of varying the echo time (TE) upon tendon signal intensity, and to determine if a modified TE value produces acceptable T1 and proton density (PD) weighted images. Fresh bovine tendons(More)
Hypertrophic olivary degeneration (HOD) is a rare type of neuronal degeneration involving the dento-rubo-olivary pathway. It is distinguished from other types of neuronal degeneration in that hypertrophy, rather than atrophy, takes place in the neurons in the inferior olivary nucleus. Prior to the invention of Magnetic Resonance Imaging (MRI), HOD was(More)
OBJECTIVE Our objective is to present the MR appearance of breast paraffinoma, a late complication of breast augmentation by liquid paraffin wax, and to correlate this appearance with the histopathologic findings that were available for three of the 11 breasts we studied. CONCLUSION Breast paraffinomas have a characteristic MR appearance that correlates(More)
Late temporal lobe necrosis is a well-known and serious complication in patients with nasopharyngeal carcinoma (NPC) following radiotherapy. Owing to the close proximity to the skull base, the medial temporal lobes are inevitably included in the target volume of irradiation. Patients with NPC provide a unique opportunity in study of delay radiation effect(More)
Cerebral abscess may sometimes mimic necrotic tumor and cystic metastases both clinically and radiologically. The imaging findings may be indistinguishable on conventional magnetic resonance imaging. Although recent studies have shown that cerebral abscess displays restricted diffusion on diffusion-weighted imaging (DWI), it is not pathognomic. Necrotic(More)
1. The bovine Galpha(14) is a member of the G(q) subfamily of G proteins that can regulate phospholipase Cbeta isoforms but the extent to which Galpha(14) recognizes different receptor classes is not known. 2. Galpha(14) was cotransfected with a variety of receptors in COS-7 cells, and agonist-induced stimulation of phospholipase C was then measured. 3.(More)