Development of Brief Image Quality Evaluation Criteria for Digital OrthoPantomography （OPG） Images in Dental Radiography

An OPG （orthopantmography） is an extra-oral radiographic imaging method which provides a panoramic or wide view of both jaws and teeth on a single image. Digital OPG images provide high contrast with more details of the dentitions. The research main objective was to produce sophisticated and effective criteria that can be used by any radiographer with sound knowledge to identify common errors of digital OPG images and to increase the concern of high frequency of errors to minimize them to give an optimum image quality. The study was designed as retrospective cross sectional study. Hundred digital OPG images are evaluated by three qualified radiographers who had dental radiography experience and four student radiographers. Paired t-test was used to see the difference between the responses of radiographers and student radiographers. Kruskal-Wallis Test was used to see difference between each evaluator. Possible errors of OPG were divided into four main categories （identification, artifact, anatomical coverage and patient positioning）. Each main category consists of sub-categories. Values of subcategories were given according to their importance to get the total of 100% for each main category. The results showed that there is no significant difference between radiographers and student radiographers’ responses and also between each evaluator. Hence it shows that the criteria were an easy understandable and user-friendly tool. And results showed the frequent error category was loss of anatomical coverage and frequent error was absence of positioning the tongue against the palate.

The Comparison of Entrance Surface Radiation Dose to the Thyroid Gland Region in Different Dental Panoramic Radiography

Introduction:The proven radio sensitivity and the position of the thyroid gland make it a significant organ during the dental radiography exposure.Objectives:This study compared the surface radiation dose to the thyroid gland region during two different techniques of two dimensional(2D)conventional orthopantomography(OPG)and three dimensional(3D)OPG reconstructed from cone beam computed tomography(CBCT).Methods:The entrance surface dose to the thyroid region of the patients was evaluated using a personal dosimeter in a sample of 156 patients who prescribed for an OPG examination.Results:The obtained mean dose values for conventional OPG and reconstructed OPG from CBCT are 7.47μSv and 28.65μSv,respectively.Further a significant difference(p<0.05)was observed between those two doses.Conclusions:A significant amount of dose reduction to the thyroid gland region can be obtained when using conventional OPG compared to the CBCT.

Challenges and optimization strategies in medical imaging service delivery during COVID-19

In coronavirus disease 2019(COVID-19),medical imaging plays an essential role in the diagnosis,management and disease progression surveillance.Chest radiography and computed tomography are commonly used imaging techniques globally during this pandemic.As the pandemic continues to unfold,many healthcare systems worldwide struggle to balance the heavy strain due to overwhelming demand for healthcare resources.Changes are required across the entire healthcare system and medical imaging departments are no exception.The COVID-19 pandemic had a devastating impact on medical imaging practices.It is now time to pay further attention to the profound challenges of COVID-19 on medical imaging services and develop effective strategies to get ahead of the crisis.Additionally,preparation for operations and survival in the post-pandemic future are necessary considerations.This review aims to comprehensively examine the challenges and optimization of delivering medical imaging services in relation to the current COVID-19 global pandemic,including the role of medical imaging during these challenging times and potential future directions post-COVID-19.

Serum HIF-1α and VEGF Levels Pre-and Post-TACE in Patients with Primary Liver Cancer

Objective To investigate the expression levels of serum hypoxia inducible factor 1 alpha(HIF-1α) and vascular endothelial growth factor(VEGF) pre-and post-transcatheter arterial chemoembolization(TACE) in patients with primary liver cancer(PLC),and correlations between prognosis factors and serum HIF-1α as well as VEGF levels.Methods Forty consecutive patients fulfilling diagnostic criteria for PLC undergoing TACE from March 2008 to May 2009 were enrolled into the study.The serum HIF-1α and VEGF levels of PLC patients pre-and 1 day,1 week,1 month post-TACE were analyzed using ELISA,and compared with that of 20 healthy volunteers.Patients were divided into complete response(CR) and partial response(PR),stable disease(SD),progressive disease(PD) groups according to the therapeutic efficacy.Pearson correlation was used to analyze the correlation between different clinical variables and serum HIF-1α and VEGF levels before TACE,and correlation between serum HIF-1α and VEGF levels was also evaluated.Results The expression levels of serum HIF-1α and VEGF in PLC patients were 154.94±83.29 and 264.00±148.10 pg/mL pre-TACE,and both of them were significantly higher than those in control group(23.84±8.15 and 69.78±21.42 pg/mL,all P<0.01).One day after TACE,both serum HIF-1α(570.64± 230.87 pg/mL) and VEGF levels(362.07±102.25 pg/mL) reached the peak values(all P<0.01).One week post-TACE,expression levels of them were decreased(198.62±92.11 and 283.52±145.46 pg/mL respectively),but still significantly higher than those before TACE(all P<0.01).The levels of both HIF-1α(133.96±57.02 vs.255.74±123.44 pg/mL) and VEGF(150.96±84.89 vs.368.95±161.90 pg/mL) in CR group 1 month post-TACE were significantly lower than those in PR+SD+PD group(all P<0.01).The level of serum HIF-1α was positively correlated with serum VEGF level(r=0.42,P<0.001).Both serum HIF-1α and VEGF levels were observed to be correlated with portal vein tumor thrombi(P<0.05) and metastasis(P<0.05).

Change of BMD after Weaning or Resumption of Menstruation in Chinese Women with Different FokI VDR-genotypes:A Randomized,Placebo-controlled,Calcium Supplementation Trial

Objective To investigate the effect of calcium supplementation on bone mineral density （BMD） in Chinese women with different Fokl vitamin D receptor （VDR） genotypes （FF, Ff, and ff） after weaning or resumption of menstruation during lactation. Methods A total of 40 subjects with the same Fokl VDR genotype were randomly divided into two groups： one received calcium tablet （600 mg once daily as CaCO3） and the other placebo tablet once daily for 1 year. At baseline, BMD was measured by dual-energy X-ray absorptiometry at lumbar spine （L2-L4） and at left hip whereas serum PICP, serum OC, and urinary CTX, serum 25（OH）VitD3, and serum estradiol were measured at weaning and I year thereafter. Results After the intervention, BMD at lumbar spine and at left hip increased significantly in all these women with a trend among different Fokl VDR genotypes such as FF 〉 Ff 〉 ff （P〈O.05, 〈0.01, and 〈0.001, respectively）. BMD at lumbar spine in women with FF VDR genotype increased much more rapidly than in those with ff VDR genotype （P〈0.05）. Compared with the control group women with the FF genotype regained more BMD after calcium supplementation （P〈0.05）. Conclusion Daily calcium 600 mg supplementation has beneficial effect on the bone health of women with FF VDR genotype.

Combination of acoustic radiation force impulse imaging, serological indexes and contrast-enhanced ultrasound for diagnosis of liver lesions

AIM To assess the value of combined acoustic radiation force impulse(ARFI) imaging, serological indexes and contrast-enhanced ultrasound(CEUS) in distinguishing between benign and malignant liver lesions. METHODS Patients with liver lesions treated at our hospital were included in this study. The lesions were divided into either a malignant tumor group or a benign tumor group according to pathological or radiological findings. ARFI quantitative detection, serological testing and CEUS quantitative detection were performed and compared. A comparative analysis of the measured indexes was performed between these groups. Receiver operating characteristic(ROC) curves were constructed to compare the diagnostic accuracy of ARFI imaging, serological indexes and CEUS, alone or in different combinations, in identifying benign and malignant liver lesions. RESULTS A total of 112 liver lesions in 43 patients were included, of which 78 were malignant and 34 were benign. Shear wave velocity(SWV) value, serum alpha-fetoprotein(AFP) content and enhancement rate were significantly higher in the malignant tumor group than in the benign tumor group(2.39 ± 1.20 m/s vs 1.50 ± 0.49 m/s, 18.02 ± 5.01 ng/m L vs 15.96 ± 4.33 ng/m L, 2.14 ± 0.21 d B/s vs 2.01 ± 0.31 d B/s; P < 0.05). The ROC curve analysis revealed that the areas under the curves(AUCs) of SWV value alone, AFP content alone, enhancement rate alone, SWV value + AFP content, SWV value + enhancement rate, AFP content + enhancement rate and SWV value + AFP content + enhancement rate were 85.1%, 72.1%, 74.5%, 88.3%, 90.4%, 82.0% and 92.3%, respectively. The AUC of SWV value + AFP content + enhancement rate was higher than those of SWV value + AFP content and SWV value + enhancement rate, and significantly higher than those of any single parameter or the combination of any two of parameters.CONCLUSION The combination of SWV, AFP and enhancement rate had better diagnostic performance in distinguishing between benign and malignant liver lesions than the use of any single parameter or the combination of any two of parameters. It is expected that this would provide a tool for the differential diagnosis of benign and malignant liver lesions.

Super-selective arterial embolization in the control of acute lower gastrointestinal hemorrhage

BACKGROUND Acute gastrointestinal bleeding is an emergency condition that can lead to significant morbidity and mortality.Embolization is considered the preferred therapy in the treatment of lower gastrointestinal bleeding when it is unrealistic to perform the surgery or vasopressin infusion in this population.Treatment of acute lower gastrointestinal(GI)bleeding(any site below the ligament of Treitz)using this technique has not reached a consensus,because of the belief that the risk of intestinal infarction in this condition is extremely high.The purpose of the study is to evaluate the effectiveness and safety of this technique in a retrospective group of patients who underwent embolization for acute lower GI bleeding.AIM To evaluate the efficacy and safety of super-selective arterial embolization in the management of acute lower GI bleeding.METHODS A series of 31 consecutive patients with angiographically demonstrated small intestinal or colonic bleeding was retrospectively reviewed.The success rate and complication rate of super-selective embolization were recorded.RESULTS Five out of thirty-one patients(16.1%)could not achieve sufficiently selective catheterization to permit embolization.Initial control of bleeding was achieved in 26 patients(100%),and relapsed GI bleeding occurred in 1 of them at 1 wk after the operation.No clinically apparent bowel infarctions were observed in patients undergoing embolization.CONCLUSION Super-selective embolization is a safe therapeutic method for acute lower GI bleeding,and it is suitable and effective for many patients suffering this disease.Importantly,careful technique and suitable embolic agent are essential to the successful operation.

Application of the Trivex system in the treatment of primary severe superficial varicose veins of the lower extremity

Purpose:The aim of this study was to evaluate the clinical effects of the Trivex system in the treatment of primary severe superficial varicose veins of the lower extremity and compare Trivex to the point-form-stripping combined with foam sclerotherapy(FS).Methods:A total of 64 patients(35 females,29 males;mean age,57?11 years[range,29–79 years])with primary severe superficial varicose veins of the lower extremity involving 64 legs were included between October 2015 and July 2019.The maximum diameter of the vein branches was>20 mm,which appeared to be cystic dilatation and forms large-scale in the crus or the thigh.All patients underwent high ligation and endovenous laser ablation or stripping of the trunk under general anesthesia.The surgical time,pain/phlebitis,number of incisions,amount of bleeding,recurrence of varicose vein,incidence of surgical site infections(SSIs),satisfaction score,and improvement in clinical symptoms were evaluated respectively with the patients in two groups:Group A,with patients who underwent treatment with the Trivex system,and Group B,patients who underwent treatment by point-form-stripping combined with FS.Results:All procedures were performed successfully.The average operative time in Group A was 56?11 min,whereas that of Group B was 90?33 min,which was a significant difference(p<0.05).Group A patients felt little pain after surgery,whereas in Group B the level of pain peaked on postoperative day 30,mostly due to thrombophlebitis after FS.There was no recurrence of varicose vein was observed in any patient,however,there were some residual effects in Group B,including the amount of bleeding volume,in-hospital stays,pain/phlebitis,and number of incisions(P<0.05).There were no significant differences with respect to SSIs,improvement in clinical symptoms,and satisfaction scores observed(p>0.05).Conclusions:This study shows that patients benefited from both treatment options.However,primary severe superficial varicose veins of the lower extremity treated with the Trivex system suffered less pain with fewer incisions than severe branches treated with the point-form-stripping combined with foam sclerotherapy(FS).In summary,the Trivex system is a suitable treatment prior to point-form-stripping combined with foam sclerotherapy(FS)for those who demand a high level of appearance,and especially for young patients,the Trivex system is recommended.

Effective Dose Levels from Computed Tomography of the Head during Contrast Studies in Nigeria

Background: Diagnostic reference levels for a number of common diagnostic radiological examinations against which individual centres could compare their performance have been recommended by relevant international agencies. Due to variations in different populations globally, local and national diagnostic reference levels are more reliable. To the best of our knowledge, no centre-specific study has been carried out and national surveys are not available. Objective: To establish a preliminary local and national diagnostic reference level in Nigeria. Methods: A pro-spective and cross-sectional study involving 30 conscious paediatrics and adult patients referred for head computed tomography scan. They were positioned supine and scanned according to the standard protocol for head computed tomography with manual mA selection. The total dose-length products were recorded at the end of the pre-contrast and post-contrast sequences respectively. The pre-contrast dose was taken into cognizance in the determination of the post-contrast value. The effective dose was established by multiplying the dose-length product by 0.0023 mSv.mGy-1.cm-1, a conversion coefficient for brain tissue adopted from the European Commission. Statistical Package for Social Sciences version 17.0 was used to analyze the data. Results: 30 paediatrics and adult patients of mixed gender participated in the study. Their ages ranged from 1 to 74 years with a mean age of 41.47 ± 23.30 years. The pre-contrast effective dose ranged from 1.93 mSv to 3.32 mSv with mean of 2.56 ± 0.51 mSv and 75th percentile of 3.11 mSv while the post-contrast effective dose ranged from 4.06 mSv to 6.97 mSv with mean of 5.27 ± 0.97 mSv and 75th percentile of 6.13 mSv. The mean effective dose from this work and two other isolated studies was 3.0 mSv. Conclusion: Although our quantified doses are below threshold limits for occupational exposures they are higher than the recommended level for the public. A further optimization of scanning protocols by the radiographers could lower the effective dose for patients undergoing contrast head computed tomography in our centre and in the country.

Mass attenuation coefficient of olive peat material for absorbing gamma ray energy

The mass attenuation coefficients (l/q) of a natural material, i.e., olive peat, were measured at photon energies of 0.059, 0.356, 0.662, 1.17, and 1.332 MeV and compared with those of concrete and Pb. The experimental samples were irradiated with 214Am, 133Ba, 137Cs, and 60Co point sources using a transmission arrangement. The olive peat samples were obtained from different areas in Jordan, namely Mafraq (sample M), Kerak (sample K), Ajloun (sample A), and Irbid (sample I), and photon energies were measured using a NaI(Tl) scintillation detector with an energy resolution of 7.6% at 662 keV. The differences in the l/q of olive peat samples and the calculated l/q of concrete were consistently within 0.7% at photon energies of 0.356–1.332 MeV. This finding indicates that olive peat can be used in radiation applications in the field of medical physics. Finally, the half-value layer (HVL) of the experimental samples was measured, and results were compared with those of concrete and Pb. Pb and concrete exhibited minimal HVL values due to their high density, and the HVL of olive peat revealed lower shielding effectiveness than that of concrete.

The Initial Implementation of the Sentinel Lymph Node Biopsy (SLNB) for Breast Cancer Management in Malta

Over the past two decades, the sentinel lymph node biopsy (SLNB) based on sentinel node (SN) being the first lymph node that harbors metastases, revolutionized breast cancer management. SLNB presents much less morbidity when compared to radical axillary lymph node dissection (ALND) where all nodes are dissected irrespective of their metastatic involvement. The purpose of this study was to evaluate the effectiveness of SLNB by investigating whether the histological characteristics of the SNs identified using scintigraphy are predictive of the histological characteristics of the ALN basin. Methods: Fifty-five female breast cancer patients underwent lymphoscintigraphy and SLNB followed by ALND. The histological status of the SN/s was correlated to the histological status of the ALNs to determine whether the SN accurately stages the ALNs in breast cancer. Results: During surgery, SNs were successfully isolated in 52 out of 55 cases (94.5%) (range, 0 to 9). No SNs were identified in 3 cases (5.5%). Results demonstrate a significant association (p = 0.05) between the metastatic status of SNs and the corresponding ALNs in 42 out of 52 patients (80.8%), but with a high false-negative rate (FNR) of 37.5%. Conclusion: The findings of this study show that the sentinel node concept provides the benefits of SLNB in the majority of instances. However, further work is required in reducing the FNR. Once the effectiveness of SLNB as a staging technique is locally established, the need of ALND in SN-negative patients would be limited, thus improving the quality of life of Maltese breast cancer patients.

Preliminary study on association between toxoplasmosis and breast cancer in Iran

Objective:To investigate the possible association between Toxoplasma gondii(T.gondii)infection and breast cancer by examining the seropositivity and serointensity rate of anti-T gondii antibodies in breast cancer patients and healthy volunteers.Methods:This study was carried out on 66 women with breast cancer which consists of 29 newly diagnosed patients(Group 1) and 37 cases undergoing treatment and regular checkups(Group 2).Also,60 healthy women(Group 3) with no history of cancer confirmed by clinical examination and imaging participated in this study.The participants were tested for T.gondii immunoglobulin G(IgG) and immunoglobulin M(IgM) antibodies by enzyme-linked immunoassays.Results:The mean age of Groups 1.2 and 3 were 43.3±6.8,41.8±5.5 and 42.3±4.9.respectively(P=0.72).Overall.104(82.5%) and 8(6.3%) out of 126 women were positive for anti-T gondii IgG and IgM antibodies,respectively.Higher seropositivity rate of anti-T.gondii antibodies(IgG) was seen in breast cancer patients(86.4%) compared with control group(78.3%)(P=0.24).IgG antibodies were detected in 89.2%of cancer patients under treatment.82.7%of newly diagnosed patients(P=0.18).IgM antibodies were found in 3(10.3%),2(5.4%)and 3(5%) in Groups 1.2 and 3.No significant difference was found between the mean titers of T.gondii IgG antibody among these groups(P=0.87).Conclusions:This study did not find any significant association between toxoplasmosis and breast cancer besides higher rates of seropositivity and serointensity in patients compared with healthy volunteers.

Feasible Method to Assess the Performance of a Lung Cancer CT Screening CAD System in Clinical Practice: Dependence on Nodule Size and Density

Detection of small pulmonary nodules is the goal of lung cancer screening. Computer-aided detection (CAD) systems are recommended to use in lung cancer computed tomography (CT) screening to increase the accuracy of nodule detection. Size and density of lung nodules are primary factors in determining the risk of malignancy. Therefore, purpose of this study is to apply computer-simulated virtual nodules based on the point spread function (PSF) measured in same scanner (maintaining spatial resolution condition) to assess the CAD system performance dependence on nodule size and density. Virtual nodules with density differences between lung background and nodule density (ΔCT) values (200, 300 and 400 HU) and different sizes (4 to 8 mm) were generated and fused on clinical images. CAD detection was performed and free-response receiver operating characteristic (FROC) curves were obtained. Results show that both density and size of virtual nodules can affect detection efficiency. Detailed results are possible to use for quantitative analysis of a CAD system performance. This study suggests that PSF-based virtual nodules could be effectively used to assess the lung cancer CT screening CAD system performance dependence on nodule size and density.

Cerebral lipiodol embolism after transarterial chemoembolization for hepatic carcinoma:A case report

We report a case of cerebral lipiodol embolism(CLE) after transarterial chemoembolization(TACE) for unresectable hepatic carcinoma(HCC).A 54-year-old man with unresectable HCC underwent TACE via the right hepatic artery and right inferior phrenic artery using a mixture of 40 mg pirarubicin and 30 mL lipiodol.His level of consciousness deteriorated after TACE,and non-contrast computed tomography revealed a CLE.The cerebral conditions improved after supportive therapy.The complication might have been due to hepatic arterio-pulmonary vein shunt caused by direct invasion of the tumor.Even though CLE is an uncommon complication of TACE,we should be aware of these rare complications in patients with high risk factors.

Effect of Gongronema latifolium on gastric emptying in healthy dogs

AIM:To investigate sonographically the effect of Gonogronema latifolium (G.latifolium) on gastric emptying of semi-solid meals in healthy dogs.METHODS:In a randomized,placebo-controlled experiment,twenty-five clinically healthy dogs were randomly allotted into five groups of five dogs in each group.The placebo group served as the control,and the low,moderate and high dose groups ingested the methanolic leaf extract of G.latifolium in capsules at 100 mg/kg,250 mg/kg and 500 mg/kg,respectively,while the prokinetic group ingested 0.5 mg/kg capsules of metoclopramide.After a 12-h fast,each group ingested its treatment capsules 30 min before the administration of a test meal.Measurements of gastric emptying and blood glucoselevels were obtained 30 min before and immediately after the ingestion of the test meal and thereafter every 15 min for 4 h.This was followed by further measurements every 30 min for another 2 h.RESULTS:The gastric emptying times of the placebo,low dose,moderate dose,high dose and prokinetic dose groups were 127.0 ± 8.2 min,135.5 ± 3.7 min,155.5 ± 3.9 min,198.0 ± 5.3 min and 59.0 ± 2.5 min,respectively.Gastric emptying times of the moderate and high dose groups were significantly slower than in the placebo control group (155.5 ± 3.9 min,198.0 ± 5.3 min vs 127.0 ± 8.2 min,P=0.000).No significant difference in gastric emptying between the low dose and placebo control groups was noted (135.5 ± 3.7 min vs 127.0 ± 8.2 min,P=0.072).Gastric emptying of the prokinetic group was significantly faster than that of the control group (59.0 ± 2.5 min vs 127.0 ± 8.2 min,P=0.000).The hypoglycaemic effect of G.latifolium and gastric emptying were inversely related (r=-0.95,P=0.000).CONCLUSION:G.latifolium delays gastric emptying and lowers postprandial blood glucose in healthy dogs.It reduces the postprandial blood glucose by delaying gastric emptying.

Production of Hypoxia-induced Corneal Edema in Aged Eyes

Purpose:Corneal thickness assessment is a common clinical procedure applied in corneal and contact lens care. This study aims to investigate the effect of age on hypoxia-induced corneal swelling.Methods:Eighteen male subjects were equally divided into the younger [(23.7 ± 0.8) years old] and older [(74.4 ± 2.5) years old] groups. Each subject wore a thick soft contact lens (uniform thickness of 0.3 mm) on the left cornea. With the contact lens in place, the baseline central corneal thickness was measured using a specially designed photo-pachometer. The lens was then patched behind the closed eyelids, producing an extremely hypoxic stress to the cornea. The change in central corneal thickness was monitored every 20 minutes with momentary disruptions to the hypoxic stress over the next 2 hours. The increase in thickness was taken as an index of corneal edema. The rate of change in corneal thickness, as derived from a non-linear mathematical model, was compared between groups.Results:The corneal thickness of both age groups increased significantly with time (P<0.000 1). The mean corneal swelling constant for the older subjects was 16.5 × 10-3 (S.E.M. = 2.65 × 10-3) and the value for the younger subjects was 46.5 × 10-3 (S.E.M. = 3.25 × 10-3). The difference was statistically significant (P < 0.000 1).Conclusion:Aging cornea has a slower hypoxia-induced edema response compared with the younger group. Whether it is caused by a decreased corneal lactate production or an increased resistance to physical expansion deserves further investigation. Eye Science 2004;20:1-5.

Thermoluminescence Energy Response of Copper and Magnesium Oxide Doped Lithium Potassium Borate Using a Monte Carlo N-Particle Code Simulation

The energy absorption coefficient of Cu-doped lithium potassium borate (LKB) dosimeter and TLD 100 was reported theoretically and checked by simulation of Monte Carlo n-particle code version 5 (MCNP5). The response of LKB:Cu for various photon energies (20 keV to 10 MeV) were determined by calculation, experiment and simulation. The obtained results were discussed and compared with TLD 100. For more precise results, the geometry specification, the source information, the material information and tallies were identified and fully described. The results obtained by simulation were determined based on the tally F6, which exhibited the response as energy-dependant on heating function instead of flux. The current results showed that the prepared dosimeter has a greater response than TLD 100 in the lower energy range and a flat response in the higher energy ranges (≥100 keV).

Current Techniques and Practices for Myocardial Stress Testing—A Comparative Survey between Malta and International Nuclear Medicine Centres

Objectives: The study compared cardiac scintigraphy stress scanning practices applied in a National Maltese Nuclear Medicine centre and in international centres. This was achieved through the design of an online survey which investigated participant knowledge of stress testing, and current procedural practice. Methods: An online survey comprising 12 questions was prepared using Survey Monkey. Professional Nuclear Medicine groups such as the Medical-Physics-Engineering community and Virtual Radiopharmacy were targeted. Access to the survey remained open for eight months during which a periodic reminder was sent to optimise the response rate. Forty-three members responded from across Europe and Australasia. Chi-square tests and comparisons between multiple responses using IBM SPSS 20 were used to evaluate the results. Information related to Maltese practice was collated separately for review and comparative purposes. Results: The online survey participants comprised United Kingdom [72%], other European countries [18%] and Australasia [9%]. The majority of respondents [n = 39] reported pharmacological stress testing as being performed either alone or in conjunction with exercise stress testing as the preferred option. Most participants [60%] were aware of local stress test protocols but had limited knowledge in relation to guidelines designed for cases where patients were not suitable for pharmacological stress testing. Conclusion: The survey provided information about procedures within participating centres for scintigraphic cardiac stress scanning. Differences were identified with regards to the preferred radiopharmaceutical tracers and procedural protocols. Further investigation of examination techniques is warranted, with the aim of increasing standardisation of protocol compliance and the application of more suitable practice.

Sonographic Estimation of Visceral Adipose Tissue in an African Population

Purpose: To establish normal values of sonographically-quantified visceral adipose tissue (VAT) in an African population and to correlate results with biomarkers. Patients and Methods: 100 male and 150 female volunteers were scanned for intra-abdominal adipose tissue thickness. Other parameters obtained include BMI, WC, and blood pressure (BP). Pearson correlation coefficient (r) was used to estimate the degree of relationship in VAT, BMI, WC, and blood pressure. Results: The mean VAT thickness was 25.36 ± 16.42 mm. VAT correlated positively and linearly with age (r = 0.651;p < 0.05), BMI (males: r = 0.745, p < 0.05, and females: r = 0.736;p < 0.05), WC (males: r = 0.797, p < 0.05;females: r = 0.779, p < 0.05), and systolic and diastolic blood pressure. (Systolic: r = 0.524, p < 0.05, and diastolic: r = 0.535, p <0.05). Conclusion: Ultrasound is a useful tool in assessing VAT during routine scans to identify patients at risk of increased blood pressure and cardiac diseases associated with obesity.

Effects of Pupil Diameter on Light Detection and Temporal Modulation

Purpose: This study compared the effects of pupil variation on light detection and temporal modulation across the central visual field.Methods:Light detection sensitivity (LDS) and low flickering frequency (6Hz) temporal modulation sensitivity (TMS) of 20 young subjects were measured from the central visual field of the right eyes using an automated perimeter (Medmont M600). The measurements were taken under 3 artificial pupils, I.e. 3 mm, 4.3 mm and 6 mm diameters.The sensitivities were grouped and averaged for different retinal eccentricities(3°, 6°, 10° and 15°).Results:TMS and LDS were reduced with increasing retinal eccentricities( P ＜ 0.001)and decreasing pupil diameters( P ＜ 0.001). TMS collected from all pupil diameters were significantly different from each other( P ＜ 0.001). Similarly, LDS under 3 mm pupil was statistically different from those of 4.3 mm and 6 mm(P ＜ 0.003). Comparison of the hills of vision showed that pupil variation resulted in significantly different slopes (P=0.001).The slopes were also found to be significantly different between TMS and LDS (P=0.012).Conclusions: The data showed that dilated pupil resulted in significantly higher sensitivities than those of smaller pupil for both visual functions. The difference in the slopes of hills of vision also suggested that the variation in retinal illumination affected the visual responses differently at various retinal eccentricitities for TMS and LDS.