Chai Hong Yeong

Automated characterization of fatty liver disease and cirrhosis using curvelet transform and entropy features extracted from ultrasound images

Fatty liver disease (FLD) is reversible disease and can be treated, if it is identified at an early stage. However, if diagnosed at the later stage, it can progress to an advanced liver disease such as cirrhosis which may ultimately lead to death. Therefore, it is essential to detect it at an early stage before the disease progresses to an irreversible stage. Several non-invasive computer-aided techniques are proposed to assist in the early detection of FLD and cirrhosis using ultrasound images. In this work, we are proposing an algorithm to discriminate automatically the normal, FLD and cirrhosis ultrasound images using curvelet transform (CT) method. Higher order spectra (HOS) bispectrum, HOS phase, fuzzy, Kapoor, max, Renyi, Shannon, Vajda and Yager entropies are extracted from CT coefficients. These extracted features are subjected to locality sensitive discriminant analysis (LSDA) feature reduction method. Then these LSDA coefficients ranked based on F-value are fed to different classifiers to choose the best performing classifier using minimum number of features. Our proposed technique can characterize normal, FLD and cirrhosis using probabilistic neural network (PNN) classifier with an accuracy of 97.33%, specificity of 100.00% and sensitivity of 96.00% using only six features. In addition, these chosen features are used to develop a liver disease index (LDI) to differentiate the normal, FLD and cirrhosis classes using a single number. This can significantly help the radiologists to discriminate FLD and cirrhosis in their routine liver screening.

Robot-assisted radiofrequency ablation of primary and secondary liver tumours: early experience.

ObjectiveComputed tomography (CT)-compatible robots, both commercial and research-based, have been developed with the intention of increasing the accuracy of needle placement and potentially improving the outcomes of therapies in addition to reducing clinical staff and patient exposure to radiation during CT fluoroscopy. In the case of highly inaccessible lesions that require multiple plane angulations, robotically assisted needles may improve biopsy access and targeted drug delivery therapy by avoidance of the straight line path of normal linear needles.MethodsWe report our preliminary experience of performing radiofrequency ablation of the liver using a robotic-assisted CT guidance system on 11 patients (17 lesions).Results/ConclusionRobotic-assisted planning and needle placement appears to have high accuracy, is technically easier than the non-robotic-assisted procedure, and involves a significantly lower radiation dose to both patient and support staff.Key Points• An early experience of robotic-assisted radiofrequency ablation is reported• Robotic-assisted RFA improves accuracy of hepatic lesion targeting• Robotic-assisted RFA makes the procedure technically easier with significant lower radiation dose

Therapeutic radionuclides in nuclear medicine: current and future prospects

The potential use of radionuclides in therapy has been recognized for many decades. A number of radionuclides, such as iodine-131 (131I), phosphorous-32 (32P), strontium-90 (90Sr), and yttrium-90 (90Y), have been used successfully for the treatment of many benign and malignant disorders. Recently, the rapid growth of this branch of nuclear medicine has been stimulated by the introduction of a number of new radionuclides and radiopharmaceuticals for the treatment of metastatic bone pain and neuroendocrine and other malignant or non-malignant tumours. Today, the field of radionuclide therapy is enjoying an exciting phase and is poised for greater growth and development in the coming years. For example, in Asia, the high prevalence of thyroid and liver diseases has prompted many novel developments and clinical trials using targeted radionuclide therapy. This paper reviews the characteristics and clinical applications of the commonly available therapeutic radionuclides, as well as the problems and issues involved in translating novel radionuclides into clinical therapies.概要本文目的本文综述了临床常用的放射性治疗方式和应用现状以及新的放射性核素从科研至临床应用所存在的问题。本文概要放射性核素的临床应用及研究已历数十载, 已有碘-131、 磷-32、 锶-90 及钇-90 等众多放射性核素被成功用于治疗良恶性疾病。随着新的放射性核素及药物不断应用于骨转移瘤疼痛治疗、 神经内分泌肿瘤及其他良恶性肿瘤治疗, 放射性核素治疗得到了快速发展。 目前, 放射性核素治疗已进入蓬勃发展期; 在亚洲, 由于甲状腺和肝脏肿瘤的高发病率, 促进了放射性核素治疗及其靶向治疗研究的日益发展。 随着放射性核素与其他药物的联合应用, 放射性核素治疗肿瘤的临床价值必将显著提高。

Computer aided diagnosis of Coronary Artery Disease, Myocardial Infarction and carotid atherosclerosis using ultrasound images: A review

The diagnosis of Coronary Artery Disease (CAD), Myocardial Infarction (MI) and carotid atherosclerosis is of paramount importance, as these cardiovascular diseases may cause medical complications and large number of death. Ultrasound (US) is a widely used imaging modality, as it captures moving images and image features correlate well with results obtained from other imaging methods. Furthermore, US does not use ionizing radiation and it is economical when compared to other imaging modalities. However, reading US images takes time and the relationship between image and tissue composition is complex. Therefore, the diagnostic accuracy depends on both time taken to read the images and experience of the screening practitioner. Computer support tools can reduce the inter-operator variability with lower subject specific expertise, when appropriate processing methods are used. In the current review, we analysed automatic detection methods for the diagnosis of CAD, MI and carotid atherosclerosis based on thoracic and Intravascular Ultrasound (IVUS). We found that IVUS is more often used than thoracic US for CAD. But for MI and carotid atherosclerosis IVUS is still in the experimental stage. Furthermore, thoracic US is more often used than IVUS for computer aided diagnosis systems.

Production and first use of 153SmCl3-ion exchange resin capsule formulation for assessing gastrointestinal motility.

We produced an enteric-coated gelatine capsule containing neutron-activated (153)Sm-labelled resin beads for use in gastrointestinal motility studies. In vitro test in simulated gastrointestinal environment and in vivo study on volunteers were performed. Scintigraphic images were acquired from ten volunteers over 24h while blood and urine samples were collected to monitor the presence of (153)Sm. All the capsules remained intact in stomach. This proved to be a safe and practical oral capsule formulation for whole gut transit scintigraphy.

Automated diagnosis of focal liver lesions using bidirectional empirical mode decomposition features

Liver is the heaviest internal organ of the human body and performs many vital functions. Prolonged cirrhosis and fatty liver disease may lead to the formation of benign or malignant lesions in this organ, and an early and reliable evaluation of these conditions can improve treatment outcomes. Ultrasound imaging is a safe, non-invasive, and cost-effective way of diagnosing liver lesions. However, this technique has limited performance in determining the nature of the lesions. This study initiates a computer-aided diagnosis (CAD) system to aid radiologists in an objective and more reliable interpretation of ultrasound images of liver lesions. In this work, we have employed radon transform and bi-directional empirical mode decomposition (BEMD) to extract features from the focal liver lesions. After which, the extracted features were subjected to particle swarm optimization (PSO) technique for the selection of a set of optimized features for classification. Our automated CAD system can differentiate normal, malignant, and benign liver lesions using machine learning algorithms. It was trained using 78 normal, 26 benign and 36 malignant focal lesions of the liver. The accuracy, sensitivity, and specificity of lesion classification were 92.95%, 90.80%, and 97.44%, respectively. The proposed CAD system is fully automatic as no segmentation of region-of-interest (ROI) is required.

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols.

Objectives This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE). Materials and Methods Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region. Results Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor. Conclusion The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners.

Reproducibility of neutron activated Sm-153 oral dose formulations intended for human administration

Neutron activation of Sm-152 offers a method of radiolabeling for the in vivo study of oral dose formulations by gamma scintigraphy. Reproducibility measurements are needed to ensure the robustness of clinical studies. 204 enteric-coated guaifenesin core tablets (10mg of Sm(2)O(3)) were irradiated by thermal neutrons to achieve 1 MBq at 48 h. Administered activities were 0.86±0.03 MBq. Good reproducibility (CV=3.5%) was observed over 24 weeks ensuring that volunteer doses were within the dose reference level of 0.8 mSv.

Gamma scintigraphic study of the hydrodynamically balanced matrix tablets of Metformin HCl in rabbits

The purpose of this study is to evaluate the in vitro and in vivo performance of gastro-retentive matrix tablets having Metformin HCl as model drug and combination of natural polymers. A total of 16 formulations were prepared by a wet granulation method using xanthan, tamarind seed powder, tamarind kernel powder and salep as the gel-forming agents and sodium bicarbonate as a gas-forming agent. All the formulations were evaluated for compendial and non-compendial tests and in vitro study was carried out on a USP-II dissolution apparatus at a paddle speed of 50 rpm. MOX2 formulation, composed of salep and xanthan in the ratio of 4:1 with 96.9% release, was considered as the optimum formulation with more than 90% release in 12 hours and short floating lag time. In vivo study was carried out using gamma scintigraphy in New Zealand White rabbits, optimized formulation was incorporated with 10 mg of 153Sm for labeling MOX2 formulation. The radioactive samarium oxide was used as the marker to trace transit of the tablets in the gastrointestinal tract. The in vivo data also supported retention of MOX2 formulation in the gastric region for 12 hours and were different from the control formulation without a gas and gel forming agent. It was concluded that the prepared floating gastro-retentive matrix tablets had a sustained-release effect in vitro and in vivo, gamma scintigraphy played an important role in locating the oral transit and the drug-release pattern.

Fusion of gamma scintigraphic and magnetic resonance images improves the anatomical delineation of radiotracer for the assessment of gastrointestinal transit

ObjectivesThis paper describes the use of gamma scintigraphic and magnetic resonance (MR) fusion images for improving the anatomical delineation of orally administered radiotracers used in gastrointestinal (GI) transit investigations. MethodsTen healthy volunteers ingested enteric-coated gelatin capsules containing 4.4±1.1 MBq 153SmCl3-labelled resin. Four external body markers containing 153Sm and Gd-DTPA were placed on the left and right lower costal margins and iliac crests of each volunteer. Anterior and posterior planar images were acquired hourly for 9 h, followed by a final single photon emission computed tomography (SPECT) image and subsequent T1-weighted images using a 1.5 T MR system. Coronal scintigraphic images were fused with MR images and assessed for diagnostic information. ResultsThe fused images revealed a combination of the tissue and organ anatomy with an overlay of the distribution of the tracer. Compared with conventional scintigraphic imaging alone, SPECT-MR fused images improved the localization of spatial and temporal movements of the radiotracer throughout the GI tract. ConclusionFusion of SPECT and MR images in conjunction with sequential scintigraphic images improved the assessment of segmental GI transit. These have the potential to provide more accurate diagnostic results and are visually powerful images that would have more widespread acceptance by nonspecialists.