Magnetic resonance imaging is gaining importance in the diagnosis of nerve and muscular disorders. The ability of magnetic resonance imaging to delineate the different muscles and the nerve in any plane has made the differentiation between the changes of neuropathy, denervation, and nerve entrapment possible. Although findings on magnetic resonance imaging are non-specific, their use, coupled with clinical symptoms and electromyographic findings, allow an accurate diagnosis to be made without resorting to invasive biopsies.
Introduction: Constipation is affecting a quarter of human population at any one time in all age groups. However, a proper gamma scintigraphic study of whole GI transit is rarely performed in Malaysia due to the lack of suitable radiopharmaceutical. Hence, this study was taken to develop a suitable radiotracer formulation for gamma scintigraphy study of whole gastric-intestinal transit. Methods: The biocompatible polystyrene (PS) incorporated with 152Sm2O3 (5%, w/v) will be used to synthesize the radiotracer. The 152Sm-labelled PS particles was neutron activated to 153Sm in a nuclear reactor for 5 minutes. Characterization of the physicochemical properties, gamma spectrometry and in-vitro radiolabeling studies in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were carried out to study the properties and stability of the radiotracer before and after neutron activation. Results: Scanning electron microscope (SEM) and particle size analysis showed that size, shape and surface morphology of the particles remained after neutron activation. The synthesized 153Sm-labelled PS radiotracer (100 mg) particles achieved an activity of 3.7 MBq after 46 hrs. As indicated by the gamma spectrometry result, there is no long half-life radioimpuirties present in the samples. The 153Sm-labelled PS particles achieved radiolabeling efficiency of more than 95% in both SGF and SIF over 72 hrs. Conclusions: A 153Sm-labelled radiotracer particles formulation has been successfully developed from biocompatible PS. The proposed formulation has the advantage of cheaper, easier to be produced and reduced radiation exposure to staff. Further studies are required to validate the in-vivo performance of 153Sm-labelled formulation for assessing GI motility and transit in clinical use.
A rare case of diffuse malignant peritoneal mesothelioma in a 71 year-old Malay man with no previous history of asbestos or radiation exposure is described. The clinical manifestation was a large abdominal mass. At laparotomy he was found to be in the advanced stage of the disease. The tumour was not resectable and patient was sent home. He gradually deteriorated and died three months after diagnosis was made. The magnetic resonance imaging (MRI) features of peritoneal mesothelioma which has not been previously reported are described.
We present a case of rare pitfall in the diagnosis of an oesophageal foreign body due to the calcified vertical plate of the cricoid to highlight the need to be aware of this entity to avoid unnecessary morbidity.
Introduction: Hepatic radioembolization is a minimally invasive procedure involving intrarterial administration of radioembolic microspheres for the treatment of liver tumours. In this study, a biocompatible polystyrene (PS) microspheres formulation containing radioactive Samarium-153 (153Sm) was synthesized and tested. The 153Sm emits both diagnostic gamma energy and therapeutic beta radiation, renders the synthesized microspheres an ideal theranostic radioembolic agent for hepatic radioembolization. Methods: First, the 152Sm2O3 (20 – 50%, w/v) was encapsulated in PS microspheres using solid-in-oil-in-water solvent evaporation method. The 152Sm-labelled PS microspheres were then activated to 153Sm (Eβmax = 807.6 keV, half-life = 46.3 hours) via 152Sm (n,γ) 153Sm reaction in a nuclear reactor with a neutron flux of 2.0 x 1012 n.cm-2.s-1. Physicochemical characterization, gamma spectroscopy and in-vitro radiolabeling studies were carried out to study the properties and stability of the microspheres before and after neutron activation. Results: The 153Sm -labelled PS microspheres achieved a nominal activity of 4.0 GBq.g-1 after 6 hours of neutron activation. Scanning electron microscope (SEM) and particle size analysis show that the microspheres remained spherical with diameters within 15 – 60 μm after neutron activation. No long half-life radioimpurities were found in the samples as revealed by the gamma spectroscopy results. The 153Sm-labelled PS microspheres achieved radiolabeling efficiency of more than 95% in saline and blood plasma over 480 hours. Conclusion: A biocompatible 153Sm-radiolabelled PS microspheres formulation has been successfully developed. The formulation achieved desirable properties for theranostic treatment of liver tumours. The formulation is relatively cheaper, easier to be produced and more readily available.
The performance of a digital mammography system (Siemens Mammomat Novation) using different target/filter combinations and tube voltage has been assessed. The objective of this study is to optimize beam quality selection based on contrast-to-noise ratio (CNR) and mean glandular dose (MGD). Three composition of breast were studied with composition of glandular/adipose of 30/70, 50/50, and 70/30. CNR was measured using 2, 4 and 6 cm-thick simulated breast phantoms with an aluminium sheet of 0.1 mm thickness placed on top of the phantom. Three target/filter combinations, namely molybdenum/molybdenum (Mo/Mo), molybdenum/rhodium (Mo/Rh) and tungsten/rhodium (W/Rh) with various tube voltage and mAs were tested. MGD was measured for each exposure. For 50/50 breast composition, Mo/Rh combination with tube voltage 26 kVp is optimal for 2 cm-thick breast. W/Rh combination with tube voltage 27 and 28 kVp are optimal for 4 and 6 cm-thick breast, respectively. For both 30/70 and 70/30 breast composition, W/Rh combination is optimal with tube voltage 25, 26 and 27 kVp, respectively. From our study it was shown that there are potential of dose reduction up to 11% for a set CNR of 3.0 by using beam quality other than that are determined by AEC selection. Under the constraint of lowest MGD, for a particular breast composition, calcification detection is optimized by using a softer X-ray beam for thin breast and harder X-ray beam for thick breast. These experimental results also indicate that for breast with high fibroglandular tissues (70/30), the use of higher beam quality does not always increase calcification detection due to additional structured noise caused by the fibroglandular tissues itself.
X-ray based radiological procedure statistics and trend in Malaysia for 1990-1994 is reported; this information allows comparisons to be made with the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) Report. Additionally it is essential information for health care planners and providers. Malaysia is categorised as a health care level II country based on the UNSCEAR definition. In 1994, the number of physicians, radiologists, x-ray units and x-ray examinations per 1000 population was 0.45, 0.005, 0.065 and 183 respectively. 3.6 million x-ray examinations were performed in 1994, with chest radiography being the commonest study (63%). Information on x-ray examinations, number of hospitals and x-ray units is reported for the Ministry of Health, private practice and teaching hospitals. Examination frequency increased in computed tomography (161%), cardiac procedures (190%), and mammography (240%); while a decrease in barium studies (-23%), cholecystography (-36%), and intravenous urography (-51%) was noted. There is a potential and need to expand and upgrade radiological services.
We report a case of a non-pulsatile groin swelling in a 38 years old male drug addict without the typical clinical signs of an aneurysm. Ultrasound revealed a left femoral artery pseudo-aneurysm. He was surgically treated and the vessels were ligated without revascularisation.
The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P > 0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (chi(2) tests).
We present a rare indirect nontraumatic cerebrospinal fluid (CSF) fistula secondary to a fourth ventricle ependymoma. The fistula resulted from rupture of the left temporal horn, distant from the tumour. The fistula was well demonstrated by MRI. High-resolution CT demonstrated a defect in the roof of the sphenoid sinus, but no leakage of CSF was seen on CT cisternography.
Development of computer-based medical inference systems is always confronted with some difficulties. In this paper, difficulties of designing an inference system for the diagnosis of arthritic diseases are described, including variations of disease manifestations under various situations and conditions. Furthermore, the need for a huge knowledge base would result in low efficiency of the inference system. We proposed a hierarchical model of the fuzzy inference system as a possible solution. With such a model, the diagnostic process is divided into two levels. The first level of the diagnosis reduces the scope of diagnosis to be processed by the second level. This will reduce the amount of input and mapping for the whole diagnostic process. Fuzzy relational theory is the core of this system and it is used in both levels to improve the accuracy.
Our preliminary experience of Somatostatin Receptor Positive Tumour Scintigraphy (SRPTS) in the management of some rare neuroendocrine tumours is highlighted. Six patients were evaluated using SRPTS. A single patient each with Zollinger-Ellison syndrome, recurrent medullary carcinoma of thyroid and Stage IV neuroblastoma. Two patients with phaeochromocytoma, and one patient with suspected insulinoma were evaluated. SRPTS was useful in three of the six patients studied i.e. patient with gastrinoma, recurrent medullary carcinoma of thyroid and metastatic neuroblastoma. SRPTS although expensive is a useful and cost-effective approach of rare endocrine tumours and it role as a first line tool in the diagnosis is discussed.
Differentiating between Cushing's disease of pituitary origin and ectopic ACTH syndrome of extra-pituitary origin remains a major challenge to the clinician because of limitations in the diagnostic accuracy of the high-dose dexamethasone suppression test. Routine use of inferior petrosal sinus sampling (IPSS) is therefore advocated by some authors for these patients. We present our preliminary experience of IPSS in 7 consecutive patients with Cushing's disease and discuss how the results impacted on the patients' management.
Photodynamic therapy (PDT) has emerged as a capable therapeutic modality for the treatment of cancer. PDT is a targeted cancer therapy that reportedly leads to tumor cell apoptosis and/or necrosis by facilitating the secretion of certain pro-inflammatory cytokines and expression of multiple apoptotic mediators in the tumor microenvironment. In addition, PDT also triggers oxidative stress that directs tumor cell killing and activation of inflammatory responses. However, the cellular and molecular mechanisms underlying the role of PDT in facilitating tumor cell apoptosis remain ambiguous. Here, we investigated the ability of PDT in association with hypericin (HY) to induce tumor cell apoptosis by facilitating the induction of reactive oxygen species (ROS) and secretion of Th1/Th2/Th17 cytokines in human hepatocellular liver carcinoma cell line (HepG2) cells. To discover if any apoptotic mediators were implicated in the enhancement of cell death of HY-PDT-treated tumor cells, selected gene profiling in response to HY-PDT treatment was implemented. Experimental results showed that interleukin (IL)-6 was significantly increased in all HY-PDT-treated cells, especially in 1 μg/ml HY-PDT, resulting in cell death. In addition, quantitative real-time PCR analysis revealed that the expression of apoptotic genes, such as BH3-interacting-domain death agonist (BID), cytochrome complex (CYT-C) and caspases (CASP3, 6, 7, 8 and 9) was remarkably higher in HY-PDT-treated HepG2 cells than the untreated HepG2 cells, entailing that tumor destruction of immune-mediated cell death occurs only in PDT-treated tumor cells. Hence, we showed that HY-PDT treatment induces apoptosis in HepG2 cells by facilitating cytotoxic ROS, and potentially recruits IL-6 and apoptosis mediators, providing additional hints for the existence of alternative mechanisms of anti-tumor immunity in hepatocellular carcinoma, which contribute to long-term suppression of tumor growth following PDT.
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.
Percutaneous image-guided needle biopsy is typically performed in highly vascular organs or in tumours with rich macroscopic and microscopic blood supply. The main risks related to this procedure are haemorrhage and implantation of tumour cells in the needle tract after the biopsy needle is withdrawn. From numerous conducted studies, it was found that heating the needle tract using alternating current in radiofrequency (RF) range has a potential to minimize these effects. However, this solution requires the use of specially designed needles, which would make the procedure relatively expensive and complicated. Thus, we propose a simple solution by using readily available coaxial core biopsy needles connected to a radiofrequency ablation (RFA) generator. In order to do so, we have designed and developed an adapter to interface between these two devices. For evaluation purpose, we used a bovine liver as a sample tissue. The experimental procedure was done to study the effect of different parameter settings on the size of coagulation necrosis caused by the RF current heating on the subject. The delivery of the RF energy was varied by changing the values for delivered power, power delivery duration, and insertion depth. The results showed that the size of the coagulation necrosis is affected by all of the parameters tested. In general, the size of the region is enlarged with higher delivery of RF power, longer duration of power delivery, and shallower needle insertion and become relatively constant after a certain value. We also found that the solution proposed provides a low cost and practical way to minimizes unwanted post-biopsy effects.
The objective of this study was to prospectively determine the incidence of venous thrombosis (VT) in the upper limbs in patients with peripherally inserted central catheters (PICC). We prospectively investigated the incidence of VT in the upper limbs of 26 patients who had PICC inserted. The inclusion criteria were all patients who had a PICC inserted, whilst the exclusion criterion was the inability to perform a venogram (allergies, previous contrast medium reaction and inability of gaining venous access). Both valved and non-valved catheters were evaluated. Prior to removal of the PICC, an upper limb venogram was performed. The number of segments involved with VT were determined. The duration of central venous catheterization was classified as; less than 6 days, between 6 days and 14 days and more than 14 days. VT was confirmed in 38.5% (10/26) of the patients. The majority 85.7% (12/14) were complete occlusive thrombi and the majority of VT only involved one segment. There was no statistical correlation between the site of insertion of the PICC and the location of VT. Neither was there any observed correlation between the occurrence of VT with the patient's history of hypertension, hypercholesterolaemia, coronary artery disease, diabetes mellitus, cardiac insufficiency, smoking or cancer. There was also no statistical correlation with the size of the catheter. In conclusion, PICCs are associated with a significant risk of upper extremity deep vein thrombosis (UEVT).
Different dental post designs and materials affect the stability of restoration of a tooth. This study aimed to analyse and compare the stability of two shapes of dental posts (parallel-sided and tapered) made of five different materials (titanium, zirconia, carbon fibre and glass fibre) by investigating their stress transfer through the finite element (FE) method. Ten three-dimensional (3D) FE models of a maxillary central incisor restored with two different designs and five different materials were constructed. An oblique loading of 100 N was applied to each 3D model. Analyses along the centre of the post, the crown-cement/core and the post-cement/dentine interfaces were computed, and the means were calculated. One-way ANOVAs followed by post hoc tests were used to evaluate the effectiveness of the post materials and designs (p=0.05). For post designs, the tapered posts introduced significantly higher stress compared with the parallel-sided post (p<0.05), especially along the centre of the post. Of the materials, the highest level of stress was found for stainless steel, followed by zirconia, titanium, glass fibre and carbon fibre posts (p<0.05). The carbon and glass fibre posts reduced the stress distribution at the middle and apical part of the posts compared with the stainless steel, zirconia and titanium posts. The opposite results were observed at the crown-cement/core interface.