Radiation dose management in fluoroscopy procedures: less is more?

The aims of this study are (1) to determine the scattered radiation dose levels in routine fluoroscopy procedures and (2) to compare them with the equivalent chest x-rays and also (3) to monitor common techniques and radiation safety measures taken by the medical officers. The study covered a sample of 105 fluoroscopic procedures performed by 18 medical officers. Each officer wore a personal pocket dosimeter inside the lead gown during each procedure. A digital dosimeter was placed near the detector of the fluoroscopy unit while a survey meter was positioned at the control panel area to record the dose levels. There were 14 types of examination included in this study. The total number of images captured was found to be the highest in barium swallow examination with 115 images, almost five times higher compared to the common practices. The longest screening time was observed in barium enema examination which is 9.15 seconds. The median of the scattered dose level was the highest in barium meal examination (165.50 μSv) which is equivalent to 8.28 times of average dose impart by chest x-ray examinations. The number of images and the length of screening time depend on the competency levels of the medical officers. They capture as many images as possible to avoid missing any abnormalities, therefore it will always be better if the fluoroscopist is consulted during each case. They should also consistently practice essential protection by minimizing exposure time, maximizing distance from the source tube and utilizing the radiation shielding

Perbandingan dos sinaran antara prosedur urografi intravena (IVU) dan tomografi berkomputer helikal tanpa kontras (UHCT) Urografi

Urografi intravena (IVU) dan tomografi berkomputer helikal tanpa kontras (UHCT) urografi adalah dua prosedur utama yang akan dijalankan semasa kajian radiologi bagi pengesanan urolitiasis (batu karang) pada sistem genitourinari. Dedahan terhadap sinaran radiasi merupakan faktor kebimbangan utama dalam kedua-dua prosedur. Oleh itu, satu kajian perbandingan dos sinaran telah dijalankan antara prosedur IVU dan UHCT urografi di samping menentukan faktor dedahan optimum bagi kedua-dua prosedur tersebut. Kajian ini telah dijalankan ke atas fantom antropomorfi seluruh tubuh mengikut protokol sebenar bagi prosedur UHCT urografi dan penghasilan radiografi bersiri beserta dengan pemberian media berkontras bagi prosedur IVU. Sebanyak tiga parameter dedahan voltan tiub digunakan iaitu 75, 80 dan 85 kVp bagi prosedur IVU dan 100, 120 dan 140 kVp bagi prosedur UHCT urografi. Hasil dos sinaran bagi prosedur IVU yang diperoleh adalah 1.40, 2.10 dan 2.79 mSv bagi 75, 80 dan 85 kVp. Manakala bagi prosedur UHCT urografi, sebanyak 0.76, 1.32 dan 1.82 mSv dos sinaran direkodkan bagi 100, 120 dan 140 kVp. Hasil kualiti imej optimum adalah menggunakan dedahan sebanyak 85 kVp bagi prosedur IVU dan 120 kVp bagi prosedur UHCT urografi. Kesimpulannya, walaupun tidak terdapat perbezaan signifikan, dos sinaran yang terhasil daripada prosedur IVU adalah tekal lebih tinggi daripada prosedur UHCT urografi

Image quality of coronary CT angiography (CCTA) using 640-slice scanner: qualitative and quantitative assessments of coronary arteries visibility

The purpose of this study was to evaluate the image quality and diagnostic accuracy of coronary computed tomography angiography (CCTA) using 640-slice scanner. Advancement of multidetector computed tomography (MDCT) technology with higher spatial, temporal resolution, and increasing detector array have improved the image quality and diagnostic accuracy of CCTA. A total of 25 patients (12 men and 13 women) underwent CCTA was chosen and data was acquired by 640-slice scanner. All 16 segments of coronary arteries were evaluated by two reviewers using a 4-likert scale for qualitative assessment. In quantitative assessment, the evaluation of 4 main coronary arteries were analysed in terms of signal intensity (SI), image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). All 25 patients with a mean age of 52.88 ± 14.75 years old and body mass index (BMI) of 24.24 ± 3.28 kg/m2 were analysed. In qualitative assessment, from the total of 400 segments, 379 segments (95 %) have diagnostic value while 21 segments do not have diagnostic value, which means 5 % artefact was detected. In quantitative assessment, there was no statistical differences in gender, race, and BMI (p>0.05). Overall evaluation showed that higher SI at the left main artery (LM) at 393.7 ± 47.19. Image noise was higher at right coronary artery (RCA) at 39.01 ± 13.97. SNR and CNR showed higher at left anterior descending (LAD) with 12.73 ± 5.17 and LM 9.14 ± 4.2, respectively. In conclusion, this study indicates that 640-slice MDCT has higher diagnostic value in CCTA examination with 95 % vessel visibility with 5 % artefact detection

Radiation dose comparison in CT thorax, CT abdomen and CT thorax-abdomen-pelvis (TAP) using 640-and 160-slice computed tomography (CT) scanners

This study was carried out to compare the effective dose, size specific dose estimation (SSDE) and scan length between genders and between CT scanner with different slice number. A total of 245 set data of radiation dose and scan length for CT scanning procedure involving thorax, abdomen and pelvis regions were obtained retrospectively for comparisons. 111 patients (60 males and 51 females) were scanned using 160-slices CT scanner while 134 patients (71 males and 63 females) were scanned using 640-slices CT scanner. Generally, there were no significant differences in the radiation dose and scan length among genders. However, differences for SSDE in CT thorax and CT thorax-abdomen-pelvis (TAP) protocols exist whereby in CT thorax protocol, 640-slices CT scanner had a significantly higher value of SSDE (9.06±2.67 mGy) than that in 160-slices CT scanner (7.82±1.33 mGy). Similarly to the CT TAP protocol, whereby 640-slices CT scanner had a significantly lower value in SSDE (9.17±1.59 mGy) than that in 160-slices CT scanner (10.76±3.72 mGy). In conclusion, there was no significant difference in the radiation dose and scan length between genders but significant difference was only observed in SSDE due to the presence of body size variation among the study population especially in different CT scanners

Ocular dimensions by three-dimensional magnetic resonance imaging in emmetropic versus myopic school children

Background: Magnetic resonance imaging (MRI) has been used to investigate eye shapes; however, reports involving children are scarce. This study aimed to determine ocular dimensions, and their correlations with refractive error, using three-dimensional MRI in emmetropic versus myopic children. Methods: Healthy school children aged < 10 years were invited to take part in this cross-sectional study. Refraction and best-corrected distance visual acuity (BCDVA) were determined using cycloplegic refraction and a logarithm of the minimum angle of resolution (logMAR) chart, respectively. All children underwent MRI using a 3-Tesla whole-body scanner. Quantitative eyeball measurements included the longitudinal axial length (LAL), horizontal width (HW), and vertical height (VH) along the cardinal axes. Correlation analysis was used to determine the association between the level of refractive error and the eyeball dimensions. Results: A total of 70 eyes from 70 children (35 male, 35 female) with a mean (standard deviation [SD]) age of 8.38 (0.49) years were included and analyzed. Mean (SD) refraction (spherical equivalent, SEQ) and BCDVA were -2.55 (1.45) D and -0.01 (0.06) logMAR, respectively. Ocular dimensions were greater in myopes than in emmetropes (all P < 0.05), with no significant differences according to sex. Mean (SD) ocular dimensions were LAL 24.07 (0.91) mm, HW 23.41 (0.82) mm, and VH 23.70 (0.88) mm for myopes, and LAL 22.69 (0.55) mm, HW 22.65 (0.63) mm, and VH 22.94 (0.69) mm for emmetropes. Significant correlations were noted between SEQ and ocular dimensions, with a greater change in LAL (0.46 mm/D, P < 0.001) than in VH (0.27 mm/D, P < 0.001) and HW (0.22 mm/D, P = 0.001). Conclusions: Myopic eyeballs are larger than those with emmetropia. The eyeball elongates as myopia increases, with the greatest change in LAL, the least in HW, and an intermediate change in VH. These changes manifest in both sexes at a young age and low level of myopia. These data may serve as a reference for monitoring the development of refractive error in young Malaysian children of Chinese origin

Alternative method to pre-diagnosed coronary artery disease using photoplethysmography: a lesson from COVID-19 pandemic

Ischemic heart disease (IHD) is one of the underlying factors that contribute to mortality in COVID-19 infected patients. IHD or coronary artery disease (CAD) is commonly diagnosed using invasive coronary angiography (ICA) or computed tomography angiography (CTA). However, these imaging modalities are costly, operationally complex and hardly accessible, especially during the pandemic. Thus, researchers have great interest in using non-invasive techniques of electrocardiography (ECG) and photoplethysmography (PPG) as alternatives to pre-diagnose the disease. This study focused on the detection of the severity of stenosis in the coronary artery using PPG among newly diagnosed IHD patients. A total of 88 patients of Hospital Canselor Tuanku Muhriz were involved. They were grouped as having severe stenosis if their stenosis percentage are at 70% or more, based on ICA or CTA evidence. A total of 73 time-domain features were analyzed in this study. Five machine learning methods were investigated to categorize the patients using up to 15 selected features. Results showed that the Discriminant Analysis method performed the best with accuracy, sensitivity and specificity of 88.46%, 100% and 70%, respectively. In conclusion, the severity of stenosis in coronary arteries has a high potential of being detected using simple non-invasive tools of PPG

12-APR segmentation and global Hu-F descriptor for human spine MRI image retrieval

The image retrieval system has been used to provide the needed correct images to the physicians while the diagnosis and treatment process is being conducted. The earlier image retrieval system was a text-based image retrieval system (TBIRS) that used keywords for the image context and it requires human’s help to manually make text annotation on the images. The text annotation process is a laborious task especially when dealing with a huge database and is prone to human errors. To overcome the aforementioned issues, the approach of a content-based image retrieval system (CBIRS) with automatic indexing using visual features such as colour, shape and texture becomes popular. Thus, this study proposes a semi-automated shape segmentation method using a 12-anatomical point representation method of the human spine vertebrae for CBIRS. The 12 points, which are annotated manually on the region of interest (ROI), is followed by automatic ROI extraction. The segmentation method performs excellently, as evidenced by the highest accuracy of 0.9987, specificity of 0.9989, and sensitivity of 0.9913. The features of the segmented ROI are extracted with a novel global Hu-F descriptor that combines a global shape descriptor, a Hu moment invariant, and a Fourier descriptor based on the ANOVA selection approach. The retrieval phase is implemented using 100 MRI data of the human spine for thoracic, lumbar, and sacral bones. The highest obtained precision is 0.9110 using a normalized Manhattan metric for lumbar bones. In a conclusion, a retrieval system to retrieve lumbar bones of the MRI human spine has been successfully developed to help radiologists in diagnosing human spine diseases

Radiation dose reduction in thoracic and abdomen-pelvic CT using tube current modulation: A phantom study

This phantom study was designed to compare the radiation dose in thoracic and abdomen-pelvic CT scans with and without use of tube current modulation (TCM). Effective dose (ED) and size-specific dose estimation (SSDE) were calculated with the absorbed doses measured at selective radiosensitive organs using a thermoluminescence dosimeter-100 (TLD-100). When compared to protocols without TCM, the ED and SSDE were reduced significantly with use of TCM for both the thoracic and abdomen-pelvic CT. With use of TCM, the ED was 6.50 ± 0.29 mSv for thoracic and 6.01 ± 0.20 mSv for the abdomen-pelvic CT protocols. However without use of TCM, the ED was 20.07 ± 0.24 mSv and 17.30 ± 0.41 mSv for the thoracic and abdomen-pelvic CT protocols, respectively. The corresponding SSDE was 10.18 ± 0.48 mGy and 11.96 ± 0.27 mGy for the thoracic and abdomen-pelvic CT protocols with TCM and 31.56 ± 0.43 mGy and 33.23 ± 0.05 mGy, for thoracic and abdomen-pelvic CT protocols without TCM, respectively. The highest absorbed dose was measured at the breast with 8.58 ± 0.12 mGy in the TCM protocols and 51.52 ± 14.72 mGy in the protocols without TCM during thoracic CT. In the abdomen-pelvic CT, the absorbed dose was highest at the skin with 9.30 ± 1.28 mGy and 29.99 ± 2.23 mGy in protocols with and without use of TCM, respectively. In conclusion, the TCM technique results in significant dose reduction, thus it is to be highly recommended in routine thoracic and abdomen-pelvic CT

Observation of Ureteric Diameter in Negative Intravenous Urogram in Hospital Universiti Kebangsaan Malaysia

Background: This study observed the widest ureteric diameter in negative intravenous urogram (IVU) examinations using low osmolar contrast media. Methods: We reviewed a total of one hundred and eighty four ureters from 92 negative IVUs. Results: The results show a mean diameter for the abdominal ureter of 4.19mm with an SD of 1.27 mm and a mean pelvic ureteric diameter of 4.45mm with an SD of 1.37 mm. The upper limits for abdominal ureter and pelvic ureter based on a confidence interval of 95% were 4.37 mm and 4.64 mm, respectively. Conclusions: There was no significant difference between the right and left ureteric diameter in both female and male subjects. There was no significant correlation between ureteric diameters and the age of subjects, from the second to the eighth decades

Predicting Outcome of Trial of Voiding Without Catheter in Acute Urinary Retention with Intravesical Prostatic Protrusion

Background: Acute urinary retention (AUR) is one of the most serious complications of benign prostatic hypertrophy. This study was done to predict the outcome of trial of voiding without catheter (TWOC) in patients with AUR with intravesical prostatic protrusion (IPP) detected on transabdominal ultrasound. Other factors such as prostatic volume and patient’s age were also assessed. Method: Patients with a first episode of AUR secondary to benign prostatic hypertrophy were assessed with ultrasound following bladder catheterization. The IPP was measured and graded (grade 1 is 5 mm or less, grade 2 is 5–10 mm and grade 3 is more than 10 mm). Success of TWOC was then correlated with the degree of IPP. Results: A total of 32 patients with AUR were included in the study. Patients with grade 3 IPP were found to have a significant failure rate compared to grade 1 (P = 0.022) and grade 2 (P = 0.041). Conclusion: Intravesical prostatic protrusion is a useful predictor of success of TWOC in patients with AUR. Patients with grade 3 IPP on ultrasound would benefit from TWOC and warrant earlier definitive surgical treatment