Biomedical subjects
Publications and source records attributed to S C H Yu.
OBJECTIVE: The objective of our study was to evaluate prospectively the preoperative use of 16-MDCT angiography and cholangiography in determining the resectability of Klatskin tumors. CONCLUSION: Preoperative MDCT angiography and cholangiography gave a good assessment of the degree of vascular and biliary involvement of the Klatskin tumor.
A case of a congenital solitary internal carotid artery with complicated anastomosis is presented. This rare anomaly was an incidental finding at cerebral angiography in a patient with a poor-grade subarachnoid hemorrhage and a ruptured anterior communicating artery aneurysm.
OBJECT: The treatment of 21 paraclinoid/ophthalmic segment internal carotid artery aneurysms (PCOSAs) over a seven year period in a regional neurosurgical center was reviewed to assess the degree of obliteration and recurrence rate of these aneurysms after treatment by surgical and endovascular methods. METHOD AND RESULT: An assessment of the clinical notes, operation records and cerebral angiograms was made to evaluate the rate of residual and recurrent aneurysms after treatment and at follow-up. In the coiling group, the aneurysm recurrence rate was eight out of fifteen aneurysms (53%). Four recurrences were from previously totally occluded aneurysms. Out of the six surgical cases, five had follow-up angiography performed. All had stable occlusions of their aneurysms including one with subtotal occlusion. Two clipping procedures after previous coiling achieved total occlusion of aneurysm on follow-up angiography. CONCLUSION: Based on our case series we conclude that PCOSAs frequently recur after primary treatment. GDC coiling was associated with a higher rate of recurrent aneurysms when compared with surgical treatment. A review of the literature on the surgical and endovascular treatment of PCOSAs support this observation.
This pictorial review concentrates on the imaging features of hepatocellular carcinoma as revealed by ultrasonography, computed tomography, magnetic resonance imaging and angiography. Understanding of the pathomorphological characteristics of the disease is important to precise image interpretation.
A case of severe lumbar artery bleeding as a complication of percutaneous nephrostomy (PCN) is presented. A 70-year-old man with coagulation disorder (factor VIII deficiency) underwent left PCN because of left hydronephrosis and abnormal renal function. The procedure was complicated by a major haemorrhage from the left first lumbar artery into the left posterior pararenal space. This case illustrates bleeding from the lumbar artery in a patient with coagulation disorder resulting in a fatal outcome. CT can provide the diagnosis, while angiography with embolisation is an effective means to control the bleeding. These examinations should be performed as soon as possible.
Three adult patients with rare vascular lesions in the parotid gland including pseudoaneurysm, arteriovenous fistula and haemangioma are discussed. All patients presented with non-specific unilateral parotid mass. In all cases high-resolution ultrasound and MRI allowed accurate diagnosis and delineation of the extent of lesion. Conventional angiogram was utilized for planning definitive surgical or endovascular treatment.
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BACKGROUND: We aimed to prospectively assess the usefulness of computer tomographic angiography (CTA) in streamlining the management of symptomatic intracranial aneurysms in a tertiary neurosurgical unit, from admission to surgery. METHODS: We performed a prospective evaluation over a 2-year period of all symptomatic intracranial aneurysms managed according to a standardized departmental protocol, to assess how CTA has impacted the decision-making process pertaining to the suitability of this investigation to proceed directly to surgery. FINDINGS: A total of 90 patients with intracranial aneurysms were treated over the 2-year period. 23 (26%) underwent endovascular occlusion while 67 (74%) patients underwent a surgical clipping procedure. In the surgical group, 22 (33%) patients had their aneurysms clipped based on CTA alone, while 45 (67%) required additional conventional angiography prior to surgery. Thus around one quarter of all patients treated for symptomatic intracranial aneurysms in our unit had their aneurysm secured surgically based solely on CTA. INTERPRETATION: CTA significantly influences the acute management of symptomatic intracranial aneurysms by streamlining the decision-making process during the early and acute management of these lesions.
Two patients with giant complex saccular aneurysms of the proximal basilar artery were managed with flow-reversal using the endovascular route. Complete obliteration of the aneurysm was successful in one patient resulting in long term survival (8 year follow-up completed). Incomplete obliteration of the aneurysm persisted in the other patient, resulting in recurrence and a fatal haemorrhage one year after treatment. Endovascular flow-reversal is a good treatment option for these lesions with a high surgical risk. However, persistent incomplete thrombosis of these aneurysms following flow-reversal should lead to the consideration of alternate treatment strategies.
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AIM: We evaluated the signal intensity change on breath-hold turbo spin-echo (TSE) T2-weighted sequences using different echo times (TE) and T2-relaxation time measurements on a single slice eight-echo sequence in the differentiation of hepatic malignancy from cavernous haemangioma. MATERIALS AND METHODS: Breath-hold TSE T2-weighted axial images of the liver were performed at TEs of 80, 120 and 160 ms in 34 patients with focal liver lesions (13 with cavernous haemangiomas, 14 with hepatocellular carcinomas and seven with metastases). The lesion percentage signal intensity change on the lower TE image to the higher TE image was calculated. T2-relaxation time was measured on a single slice eight-echo sequence. RESULTS: The TE pair 80/160 ms on breath-hold TSE T2-weighted sequences gave a performance (100% sensitivity, 92% specificity, 95% positive predictive value and 100% negative predictive value) better than other TE pairs in differentiating haemangioma from malignancy. Addition of fat-suppression compromised the diagnostic performance for all TE-pairs. The use of T2 relaxation time threshold of < 112 ms as indicative of malignant lesion achieved a 100% sensitivity, 77% specificity, 88% positive predictive value and 100% negative predictive value. CONCLUSION: Percentage signal intensity change on breath-hold TSE T2-weighted sequences at TE 80/160 ms appears to be a quick and potentially useful means of differentiating hepatic malignancy from haemangioma.
AIMS: To study the prevalence and severity of liver diseases of transfusion dependent thalassaemia major patients, and correlate the histological and biochemical changes of iron overload in liver with the peripheral blood markers. METHOD: Liver biopsy was performed to assess the histological changes and liver iron content (LIC). RESULTS: One hundred patients were evaluated (median age 11.7 years, range 1.5-27). A total of 81 liver biopsies were performed in 73 patients; 43 samples were analysed for LIC. Grade 3-4 haemosiderosis and hepatic fibrosis was found in 44% and 30% of patients respectively; both were significantly associated with higher serum ferritin, liver enzymes, and LIC. Very high LIC (>15 mg/g dry weight) was present in 16.3% of patients. CONCLUSION: Severe haemosiderosis and hepatic fibrosis were common in patients with thalassaemia major despite the use of chelation therapy. Liver biopsy provided information on fibrosis and LIC which could not be accurately predicted from peripheral blood markers.
Nine patients with vertebrobasilar artery dissections who presented with neurological symptoms or subarachnoid haemorrhage were identified and treated in the Neurosurgical Unit at the Prince of Wales Hospital in Hong Kong. An account of these patients is given and their treatment described. This paper further reviews selected literature to outline the concepts and appropriate management of vertebrobasilar artery dissections.
PURPOSE: We investigate the use of non-contrast helical computerized tomography (NCHCT) in the measurement of differential renal parenchymal volume as a surrogate for differential creatinine clearance (CrCl) for unilateral chronically obstructed kidney. MATERIALS AND METHODS: Patients with unilateral chronically obstructed kidneys with normal contralateral kidneys were enrolled. Ultrasonography (USG) of the kidneys was first done with the cortical thickness of the site with the most renal substance in the upper pole, mid-kidney, and lower pole of both kidneys were measured, and the mean cortical thickness of each kidney was calculated. NCHCT was subsequently performed for each patient. The CT images were individually reviewed with the area of renal parenchyma measured for each kidney. Then the volume of the slices was summated to give the renal parenchymal volume of both the obstructed and normal kidneys. Finally, a percutaneous nephrostomy (PCN) was inserted to the obstructed kidney, and CrCl of both the obstructed kidney (PCN urine) and the normal side (voided urine) were measured two 2 after the relief of obstruction. RESULTS: From March 1999 to February 2001, thirty patients were enrolled into the study. Ninety percent of them had ureteral calculi. The differential CrCl of the obstructed kidney (%CrCl) was defined as the percentage of CrCl of the obstructed kidney as of the total CrCl, measured 2 weeks after relief of obstruction. The differential renal parenchymal volume of the obstructed kidney (%CTvol) was the percentage of renal parenchymal volume as of the total parenchymal volume. The differential USG cortical thickness of the obstructed kidney (%USGcort) was the percentage of mean cortical thickness as of the total mean cortical thickness. The Pearson's correlation coefficient (r) between %CTvol and %CrCl and that between %USGcort and %CrCl were 0.756 and 0.543 respectively. The regression line was %CrCl = (1.00) x %CTvol - 14.27. The %CTvol overestimated the differential creatinine clearance by about 14%, but the correlation is good. CONCLUSION: The differential renal parenchymal volume measured by NCHCT provided a reasonable prediction of differential creatinine clearance in chronically obstructed kidneys.