Gadoxetic acid in hepatocellular carcinoma and liver metastases: pearls and pitfalls.

Gadoxetic disodium (Primovist) is a hepatocyte-specific magnetic resonance imaging (MRI) contrast agent with increasing popularity with its unique dual dynamic and excretory properties in focal liver lesion detection and characterisation. In-depth knowledge of its diagnostic utility and pitfalls in hepatocellular carcinoma (HCC) and liver metastases is crucial in facilitating clinical management. The current article reviews the pearls and pitfalls in these aspects with highlights from the latest research evidence. Pearls for common usage of Primovist in HCC includes detection of precursor cancer lesions in cirrhotic patients. Hepatobiliary phase hypointensity precedes arterial phase hyperenhancement (APHE) in hepatocarcinogenesis. Hepatobiliary phase hypointense nodules without APHE can represent early or progressed hepatocellular carcinoma (HCC) and high-grade dysplastic nodules. In addition, Primovist is useful to differentiate HCC from pseudolesions. Pitfalls in diagnosing HCC include transient tachypnoea in the arterial phase, rare hepatobiliary phase hyperintense HCC, and decompensated liver cirrhosis compromising image quality. Primovist is currently the most sensitive technique in diagnosing liver metastases before curative hepatic resection. Other patterns of enhancement of liver metastases, "disappearing" liver metastases are important pitfalls. Radiologists should be aware of the diagnostic utility, limitations, and potential pitfalls for the common usage of hepatobiliary specific contrast agent in liver MRI.

Patterns of COVID-19 on computed tomography imaging.

PURPOSE: As the designated tertiary referral centre for infectious diseases in Hong Kong, our hospital received the city's first group of patients diagnosed with coronavirus disease 2019 (COVID-19). Herein, we studied the earliest patients admitted to our centre in order to clarify the typical radiological findings, particularly computed tomography (CT) findings, associated with COVID-19. METHODS: From 22 January 2020 to 29 February 2020, 19 patients with confirmed COVID-19 underwent high-resolution or conventional CT scans of the thorax in our centre. The CT imaging findings of these patients with confirmed COVID-19 in Hong Kong were reviewed in this study. RESULTS: Ground-glass opacities (GGO) with peripheral subpleural distribution were found in all patients (100%). No specific zonal predominance was observed. All lobes were involved in 16 (84.2%) patients, focal subsegmental consolidations were observed in 14 (73.7%) patients, and interlobular septal thickening was present in 12 (63.2%) patients. No mediastinal lymph node enlargement, centrilobular nodule, or pleural effusion was detected in any of the patients. Other imaging features present in several patients include bronchial dilatation, bronchial wall thickening, and crazy-paving patterns. CONCLUSIONS: Peripheral subpleural GGO without zonal predominance in the absence of centrilobular nodule, pleural effusion, and lymph node enlargement were consistent findings in patients with confirmed COVID-19. The observed radiological patterns on CT scans can help identify COVID-19 and assess affected patients in the context of the ongoing outbreak.

Duplex sonography for detection of deep vein thrombosis of upper extremities: a 13-year experience.

OBJECTIVES: To determine the prevalence and characteristics of sonographically evident upper-extremity deep vein thrombosis in symptomatic Chinese patients and identify its associated risk factors. SETTING: Regional hospital, Hong Kong. PATIENTS: Data on patients undergoing upper-extremity venous sonography examinations during a 13-year period from November 1999 to October 2012 were retrieved. Variables including age, sex, history of smoking, history of lower-extremity deep vein thrombosis, major surgery within 30 days, immobilisation within 30 days, cancer (history of malignancy), associated central venous or indwelling catheter, hypertension, diabetes mellitus, sepsis within 30 days, and stroke within 30 days were tested using binary logistic regression to understand the risk factors for upper-extremity deep vein thrombosis. MAIN OUTCOME MEASURES: The presence of upper-extremity deep vein thrombosis identified. RESULTS: Overall, 213 patients with upper-extremity sonography were identified. Of these patients, 29 (13.6%) had upper-extremity deep vein thrombosis. The proportion of upper-extremity deep vein thrombosis using initial ultrasound was 0.26% of all deep vein thrombosis ultrasound requests. Upper limb swelling was the most common presentation seen in a total of 206 (96.7%) patients. Smoking (37.9%), history of cancer (65.5%), and hypertension (27.6%) were the more prevalent conditions among patients in the upper-extremity deep vein thrombosis-positive group. No statistically significant predictor of upper-extremity deep vein thrombosis was noted if all variables were included. After backward stepwise logistic regression, the final model was left with only age (P=0.119), female gender (P=0.114), and history of malignancy (P=0.024) as independent variables. History of malignancy remained predictive of upper-extremity deep vein thrombosis. CONCLUSIONS: Upper-extremity deep vein thrombosis is uncommon among symptomatic Chinese population. The most common sign is swelling and the major risk factor for upper-extremity deep vein thrombosis identified in this study is malignancy.

Lymphoscintigraphy in the evaluation of lower extremity lymphedema: local experience.

OBJECTIVE: To review our local experience in the use of lymphoscintigraphy to evaluate lymphedema of the lower extremities. DESIGN: Retrospective case series. SETTING: A local regional hospital in Hong Kong. PATIENTS: Images and records of all patients presenting to our hospital with suspected lower limb lymphedema from 1998 to 2011 for whom lymphoscintigraphy was performed were reviewed. MAIN OUTCOME MEASURES: Lymphoscintigraphy findings and clinical outcomes. RESULTS: In all, 24 patients (13 males and 11 females; age range, 14-83 years) had undergone lymphoscintigraphy for suspected lower limb lymphedema. Eight cases were confirmed positive, including one with lymphangiectasia, five with lymphatic obstruction, and two with lymphatic leakage. No complication was encountered. CONCLUSION: Lymphoscintigraphy is safe and effective for the evaluation of lymphedema in lower extremities.

Ultrasound-guided plugged percutaneous biopsy of solid organs in patients with bleeding tendencies.

OBJECTIVE: To establish and verify the utility of plugging biopsy tracts, using a combination of Gelfoam slurry and torpedo in the prevention of post-biopsy bleeding in patients at high risk of post-procedure haemorrhage following ultrasound-guided percutaneous biopsy of solid organs. DESIGN: Case series. SETTING: Radiology Department of a regional hospital in Hong Kong. PATIENTS: In our unit, all patients considered to be at high risk of post-biopsy haemorrhage of a solid organ underwent ultrasound-guided plugged percutaneous biopsy from year 2005 to 2012. INTERVENTIONS: All the included patients had undergone real-time ultrasound-guided biopsy of solid organs (liver in 10 and spleen in one patient). In all cases, a combination of a coaxial introducer needle and Temno needle were used. After adequate specimens were obtained, Gelfoam slurry (for distal embolisation) followed by Gelfoam torpedo (for proximal embolisation) were used to plug the biopsy tract. MAIN OUTCOME MEASURES: Technical success, any post-biopsy haemorrhage treated by transfusion or other intervention, and plugging-related complications were reviewed for each patient. RESULTS: Technical success was achieved in all patients and none experienced post-biopsy haemorrhage treated by blood transfusion or any other intervention. CONCLUSION: Plugging of the biopsy tract with Gelfoam slurry followed by Gelfoam torpedo is a direct and simple procedure that can safely and effectively prevent haemorrhage in patients at high risk of post-biopsy haemorrhage.

Ultrasound-guided thrombin injection for pseudoaneurysms: a case series at a local hospital.

Post-catheterization pseudoaneurysms are increasingly prevalent due to widespread use of endovascular procedures. Ultrasound-guided thrombin injection has emerged as a treatment of choice for these pseudoaneurysms. We review our experience performing this procedure for a series of cases from 2007 to 2010 with different clinical manifestations at a single hospital in Hong Kong. We achieved a high technical success rate with no complications.

Evaluation of performance of measurement of faecal α(1)-antitrypsin clearance and technetium-99m human serum albumin scintigraphy in protein-losing enteropathy.

BACKGROUND AND AIM: Our study aimed to compare the performance of faecal α(1)-antitrypsin clearance (AATC) and radiolabelled human serum albumin (HSA) scintigraphy in protein-losing enteropathy (PLE). METHODS: Patients studied by both AATC and technetium-99m ((99m)Tc)-labelled HSA scintigraphy were recruited and categorized into PLE and non-PLE groups based on clinical and laboratory findings. The performance of AATC and (99m)Tc-labelled HSA scintigraphy was evaluated using clinical diagnosis of PLE as a gold standard. RESULTS: 29 patients were recruited and 13 patients were considered to have definite PLE (PLE group). In the PLE group, all patients had a positive HSA scinigraphy and 10 (77%) had demonstrable positive tracing in the early phase. Conversely, only 6 of them (46%) had elevated AATC level (>13 m/day). Results of (99m)Tc-labelled HSA scan (but not AATC) showed significant agreement with the clinical diagnosis (κ 0.35, p = 0.013). (99m)Tc-labelled HSA scintigraphy carried higher sensitivity (100 vs. 46%) and negative predictive value (100 vs. 63%) compared to AATC in diagnosing PLE. The correlation between the results of these two investigations was only modest (κ 0.27, p = 0.04). The area under the receiver operating characteristic curve of AATC level showed no optimal diagnostic cut-off for PLE. CONCLUSION: (99m)Tc-labelled HSA scintigraphy was superior to AATC in diagnosing PLE.

Small bowel enema use in an Asian population: our eleven years of local experience.

OBJECTIVE: To retrospectively analyse the outcome of patients who underwent investigation by small bowel enema in a local centre. DESIGN: Case series. SETTING: Regional hospital, Hong Kong. PATIENTS: All patients referred for small bowel enema in a local hospital from 1 January 1999 to 31 December 2009 were identified; respective findings from imaging and clinical records were reviewed. RESULTS: A total of 341 patients were referred for small bowel enema, of whom 289 successfully completed the examination. There were 211 patients whose small bowel enema findings were considered normal and 78 were regarded as abnormal. The sensitivity of this investigation was 73% and its specificity was 91%. The respective positive and negative predictive values were 66% and 93%. CONCLUSIONS: The selection of patients by clinicians with specific indications for small bowel enema is essential for making effective use of small bowel enema as an investigative tool.

Pocket-sized versus standard ultrasound machines in abdominal imaging.

The pocket-sized ultrasound machine has emerged as an invaluable tool for quick assessment in emergency and general practice settings. It is suitable for instant and quick assessment in cardiac imaging. However, its applicability in the imaging of other body parts has yet to be established. In this pictorial review, we compared the performance of the pocketsized ultrasound machine against the standard ultrasound machine for its image quality in common abdominal pathology.

Foreign body ingestion: comparison of diagnostic accuracy of computed tomography versus endoscopy.

PURPOSE: To investigate and compare the sensitivity and specificity of computed tomography and of endoscopy, as diagnostic tests for foreign body ingestion. MATERIALS AND METHODS: Over a two-year period, Asian patients with suspected foreign body ingestion were studied. The clinical findings, computed tomography images, endoscopic results, treatment and outcomes were prospectively analysed. RESULTS: Over the study period, 193 patients were admitted for foreign body ingestion, complaining of a persistent foreign body sensation in the neck. The sensitivity and specificity of computed tomography were 78 and 96 per cent, respectively; the positive predictive value was 75 per cent and the negative predictive value 97 per cent. The diagnostic accuracy of computed tomography was 94 per cent. CONCLUSION: Our study showed that computed tomography had high negative predictive value and accuracy in the diagnosis of foreign body ingestion. It was useful if endoscopy showed negative findings but the patient still had persistent symptoms of foreign body ingestion.