A multiscale model for bioimpedance dispersion of liver tissue.

Radio-frequency ablation (RFA) has been used in liver surgery to minimize blood loss during tissue division. However, the current RFA tissue division method lacks an effective way of determining the stoppage of blood flow. There is limitation on the current state-of-the-art laser Doppler flow sensor due to its small sensing area. A new technique was proposed to use bioimpedance for blood flow sensing. This paper discusses a new geometrical multiscale model of the liver bioimpedance incorporating blood flow impedance. This model establishes correlation between the physical tissue structure and bioimpedance measurement. The basic Debye structure within a multilevel framework is used in the model to account for bioimpedance dispersion. This dispersion is often explained by the Cole-Cole model that includes a constant phase element without physical explanation. Our model is able to account for reduced blood flow in its output with changes in permittivity in gamma dispersion that is mainly due to the polarization of water molecules. This study demonstrates the potential of a multiscale model in determining the stoppage of blood flow during surgery.

Inflammatory pseudotumour arising from periampullary carcinoid: a "cancer-like" tumour in a "fake" tumour.

Carcinoid tumours of the gastrointestinal tract are uncommon, generally slow-growing and associated with a good prognosis. We present a 52-year-old Chinese woman with a carcinoid at the ampulla of Vater, a site far less common than other areas of the gastrointestinal tract. Preoperative imaging showed a pancreatic mass with displacement and possible invasion of the portal vein associated with peripancreatic nodal enlargement. A radical pancreaticoduodenectomy with portal vein wedge excision was performed. An intraoperative biopsy of the enlarged nodes was negative for malignancy and postoperative histology of the large pancreatic mass yielded a surprising finding of a carcinoid tumour at the ampulla of Vater with a large inflammatory pancreatic mass adherent to the portal vein. This is an uncommon case associated with "pseudotumour pancreatitis", causing biliary and pancreatic duct obstruction mimicking a large tumour in the head of the pancreas.

Mimicry of acute cholecystitis from Wilson's disease.

We present a 33-year-old Chinese woman with Wilson's disease in whom ultrasonography and computed tomography showed gallbladder features suggestive of acute cholecystitis. Incongruence in liver function prompted further investigations with the final diagnosis of Wilson's disease, complicated by oedema of the gallbladder mimicking acute cholecystitis. The patient was subsequently treated nonoperatively, and is well on follow-up.

Stenting before laparoscopic common bile duct exploration: a helpful strategy.

We describe a 43-year-old man who had a difficult endoscopic retrograde cholangiopancreatography, allowing only placement of a stent without removal of the common bile duct stone. He subsequently underwent laparoscopic cholecystectomy with laparoscopic common bile duct exploration and primary closure after laparoscopic choledochotomy.

Focal nodular hyperplasia presenting as acute abdomen.

Focal nodular hyperplasia (FNH) is a benign liver tumour with an asymptomatic course, rarely causing complications. When the diagnosis is certain, only watchful observation is necessary. We highlight an interesting case of a 42-year-old woman with a FNH that ruptured and became haemorrhagic, thus presenting as an acute surgical abdomen. The diagnosis was only established after surgical resection with histopathological confirmation. Although haemorrhage of hepatic FNH is extremely rare, this case highlights the small risk of rupture in large lesions.

Recurrent appendicitis as a cause of recurrent right iliac fossa pain.

Recurrent appendicitis is defined when patients with recurring similar right iliac fossa pain had acute appendicitis confirmed at the time of operation and the pain completely subsided after surgery. We conducted a retrospective study on our patients with appendicitis. There were 290 patients with appendicitis over a two-year period and 33 patients (11%) had reported recurring pain prior to the presentation. Majority had one prior episode but 15% had multiple episodes of right iliac fossa pain. Fifty-eight percent of the episode occur within six months of the presentation. We conclude that recurrent appendicitis should be considered as a differential diagnosis in patients with recurrent right iliac fossa pain.

Effects of dietary intervention and strength training on blood lipid level in obese children.

AIMS: To evaluate effects of a low energy diet, with or without strength training, on blood lipid profile in obese children. METHODS: Eighty two obese children were enrolled into a six week dietary programme, and were randomly allocated to a training group or a non-training group. The training group underwent regular exercise sessions with emphasis on strength training. RESULTS: Height increased significantly, with a non-significant reduction in body mass index. Fat free mass increased significantly in the training group. Serum total cholesterol was significantly reduced in both groups. The LDL:HDL ratio significantly decreased in the training group. CONCLUSION: Results support the potentially beneficial effects of both diet and physical training. Further and longer term evaluation of such programmes is required.