Chih ng Yu

Pyogenic liver abscess treated by percutaneous catheter drainage: MDCT measurement for treatment outcome

OBJECTIVE To analyze multidetector computed tomographic (MDCT) parameters in patients with pyogenic liver abscess (PLA), and to identify which parameters can be predicted percutaneous catheter drainage (PCD) treatment outcome. MATERIALS AND METHODS Clinical, laboratory and MDCT findings of 175 patients with PLA who had undergone PCD were retrospectively reviewed. All abscesses shown on MDCT were evaluated for size, margin, attenuation values, location, number of large (>3cm) abscesses, presence of a cystic component, presence of gas, and the shortest length to the liver capsule. Univariate and multivariate analyses of the MDCT parameters that affect PCD treatment outcome was performed. For continuous data of MDCT parameters (abscess size and the shortest length), we used receiver-operating-characteristic (ROC) curve to determine the optimal cut-off values. RESULTS PCD was failed in 32 patients and the overall failure rate was 18.28%. Multivariate analysis revealed that PCD failure was predicted by the presence of gas (odds ratio [OR], 42.67), a large abscess (OR 1.21), low minimal attenuation values (OR 1.02), wide range of attenuation values (OR 1.01), a shorter length to the liver capsule (OR 0.09) and lack of a cystic component (OR 0.09) of the PLA. ROC curve showed that the shortest length less than 0.25cm and an abscess size greater than 7.3cm were the optimal cut-off values predicting PCD treatment failure. CONCLUSION Among these MDCT parameters, gas formation within PLA was the most important predictor for PCD failure. Surgical intervention might be considered early in high-risk patients of PCD failure.

Strangulated transmesosigmoid hernia: CT diagnosis

We present a rare case of strangulated closed loop small bowel obstruction secondary to a trans-mesosigmoid hernia to emphasize the diagnostic role of computed tomography in patients with no history of previous surgery. The characteristic computed tomographic features showed a cluster of dilated, fluid-filled, U- and C-shaped loops of small bowel entrapped the left posterior and lateral to the sigmoid colon through a defect in the mesosigmoid, which caused anterior and medial displacement of the sigmoid colon.

CT diagnosis of small bowel obstruction due to phytobezoar.

BACKGROUND AND PURPOSE Small bowel obstruction (SBO) is a commonly encountered abdominal problem in the emergency ward. Phytobezoar is an uncommon cause of SBO which has specific radiographic findings on computed tomography (CT). This study evaluated the CT appearance of small bowel phytobezoar. METHODS Eighty two patients with SBO who underwent CT examination and surgical treatment over a 6-year period were included. The presence of fecal ball sign, defined as a clearly distinguishable, ovoid or round intraluminal mass with mottled gas pattern outlined by fluid or oral contrast material in the dilated small bowel at the site of obstruction, and abruptly collapsed lumen beyond the lesion on CT was evaluated in all cases. The CT findings of the patients with SBO and the patients with fecal ball sign on CT were reviewed. The diagnosis was established based on surgical findings. RESULTS Fecal ball sign was identified in 9 of the 82 patients. Operative findings revealed that SBO was secondary to phytobezoar in 7 of these patients. The specificity and sensitivity of fecal ball sign in the diagnosis of SBO secondary to phytobezoar were 97% and 100%, respectively. CONCLUSIONS Fecal ball sign is accurate in the preoperative diagnosis of phytobezoar as the underlying cause of SBO. Early recognition of fecal ball sign in the CT study is of paramount importance in precise preoperative diagnosis in patients with SBO.

Using Multidetector-Row CT for the Diagnosis of Afferent Loop Syndrome Following Gastroenterostomy Reconstruction

Purpose To assess the clinical manifestations and multidetector-row computed tomography (MDCT) findings of afferent loop syndrome (ALS) and to determine the role of MDCT on treatment decisions. Materials and Methods From January 2004 to December 2008, 1,100 patients had undergone gastroenterostomy reconstruction in our institution. Of these, 22 (2%) patients were diagnosed as ALS after surgery that included Roux-en-Y gastroenterotomy (n=9), Billroth-II gastrojejunostomy (n=7), and Whipples operation (n=6). Clinical manifestations and MDCT features of these patients were recorded and statistically analyzed. The presumed etiologies of obstruction shown on the MDCT were correlated with clinical information and confirmed by surgery or endoscopic biopsy. Results The most common clinical symptom was acute abdominal pain, presenting in 18 patients (82%). We found that a fluid-filled C-shaped afferent loop in combination with valvulae conniventes projecting into the lumen was the most common MDCT features of ALS. Malignant causes of ALS, such as local recurrence and carcinomatosis, are the most common etiologies of obstruction. These etiologies and associated complications can be predicted 100% by MDCT. Conclusion Our results suggest that MDCT is a reliable modality for assessing the etiologies of ALS and guiding treatment decisions.

Positioning a safe gastric puncture point before percutaneous endoscopic gastrostomy.

To position a safe gastric puncture point prior to the percutaneous endoscopic gastrostomy (PEG) a technique using an abdominal plain film with a gastric insufflation was assessed. After insufflated with 500 ml of air, an abdominal plain film was obtained before PEG in 84 patients. The body of the stomach near the angularis, equidistant from the greater and lesser curves, was defined as the optimal gastric puncture point. The location of the puncture points varied greatly, being situated over the right upper quadrant in 31% of patients, left upper in 59%, right lower in 5% and left lower quadrant in 5% of patients. The marked puncture points on abdominal film in some patients were shown to be partially covered by colon or small bowel loop, lie high under the costal margin, or low beneath the umbilicus. An abdominal plain film utilising a gastric insufflation technique prior to PEG may help to determine optimal gastric puncture site selection. Use this technique in clinical practice might hasten procedural time, provide better assurance to the clinical doctor, and provide an added margin of safety for the patient.

Recurrence of hepatocellular carcinoma after liver transplantation presenting as anastomotic biliary stricture

A 52-year-old man visited our hospital complaining of anorexia and fatigue two months after receiving orthotopic liver transplantation for hepatocellular carcinoma. A laboratory investigation demonstrated a clinical picture of obstructive jaundice. T-tube cholangiography showed biliary stricture over the anastomotic site. Percutaneous transluminal balloon dilatation and stenting was attempted but failed. Magnetic resonance cholangiography showed possible tumor recurrence over the site of the anastomotic biliary stricture. A biopsy sample was obtained via ultrasound-guided aspiration and histopathological study revealed inflammatory and fibrotic changes. With high suspicion of recurrence of the hepatocellular carcinoma, surgical exploration was performed and an intraoperative frozen section proved the recurrence. We thus diagnosed this case as a recurrence of hepatocellular carcinoma after liver transplantation. To our knowledge, there have been no previous reports of early tumor recurrence after liver transplantation being the cause of an anastomotic biliary stricture.

Occult insulinoma on the cranial surface of pancreatic body: Essential role of coronal MR imaging

Insulinomas are the most common islet cell tumor of the pancreas. They are usually small at clinical presentation and the diagnosis is mainly based on clinical and laboratory findings. Tumor localization may require several modalities, including ultrasonography, computed tomography (CT), magnetic resonance (MR) imaging, and angiography. We report a case of insulinoma at the cranial surface of the pancreas, which was not identified on axial but only on coronal MR imaging. The importance of coronal imaging in detecting such small pancreatic tumors is emphasized.