Displaying publications 1 - 20 of 54 in total

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  1. Tan SK, Yeong CH, Raja Aman RRA, Ng KH, Abdul Aziz YF, Chee KH, et al.
    Br J Radiol, 2018 Jul;91(1088):20170874.
    PMID: 29493261 DOI: 10.1259/bjr.20170874
    OBJECTIVE: This study aimed (1) to perform a systematic review on scanning parameters and contrast medium (CM) reduction methods used in prospectively electrocardiography (ECG-triggered low tube voltage coronary CT angiography (CCTA), (2) to compare the achievable dose reduction and image quality and (3) to propose appropriate scanning techniques and CM administration methods.

    METHODS: A systematic search was performed in PubMed, the Cochrane library, CINAHL, Web of Science, ScienceDirect and Scopus, where 20 studies were selected for analysis of scanning parameters and CM reduction methods.

    RESULTS: The mean effective dose (HE) ranged from 0.31 to 2.75 mSv at 80 kVp, 0.69 to 6.29 mSv at 100 kVp and 1.53 to 10.7 mSv at 120 kVp. Radiation dose reductions of 38 to 83% at 80 kVp and 3 to 80% at 100 kVp could be achieved with preserved image quality. Similar vessel contrast enhancement to 120 kVp could be obtained by applying iodine delivery rate (IDR) of 1.35 to 1.45 g s-1 with total iodine dose (TID) of between 10.9 and 16.2 g at 80 kVp and IDR of 1.08 to 1.70 g s-1 with TID of between 18.9 and 20.9 g at 100 kVp.

    CONCLUSION: This systematic review found that radiation doses could be reduced to a rate of 38 to 83% at 80 kVp, and 3 to 80% at 100 kVp without compromising the image quality. Advances in knowledge: The suggested appropriate scanning parameters and CM reduction methods can be used to help users in achieving diagnostic image quality with reduced radiation dose.

    Matched MeSH terms: Coronary Angiography/methods*; Computed Tomography Angiography/methods*
  2. Vu H, Khanh Tuong TT, Hoang Lan N, Quoc Thang T, Bilgin K, Hoa T, et al.
    Clin Ter, 2022 11 15;173(6):565-571.
    PMID: 36373456 DOI: 10.7417/CT.2022.2483
    Background: Various non-invasive methods have been studied for assessing the severity of fatty liver disease and coronary atherosclero-sis. However, the correlation between hepatic steatosis and coronary atherosclerosis has not been fully studied, either globally or specifically in Vietnam. This study investigated the association between nonalcoholic fatty liver disease (NAFLD) and coronary atherosclerosis using coronary computed tomography angiography (CCTA).

    Methods: An analytical cross-sectional study was performed, including 223 patients treated by the Cardiology Department, the Emergency Interventional Cardiology Departments, and the Internal Cardiology Clinic of Thong Nhat Hospital.

    Results: In our cohort of 223 patients, the NAFLD was detected in 66% of the population, the mean coronary artery stenosis (CAS) was 44.54% ± 20.23%, and the mean coronary artery calcium score (CACS) was 3569.05 ± 425.99, as assessed using the Agatston method. The proportion of patients with significant atherosclerotic plaque (CAS 50%) >was 32%, whereas the remaining 68% had insignificant stenosis. Among our study population, 16% had no coronary artery calcification, 38% had mild calcification, and 46% had moderate to severe calcification. In the group of NAFLD patients, 33.3% had significant atherosclerotic plaque, which was not significantly different from the rate in individuals without NAFLD (p = 0.51). Mild coronary artery calcification was detected in 37.4% of NAFLD patients, and moderate to severe calcification was detected in 48.3% (p = 0.45).

    Conclusions: NAFLD was not found to be strongly associated with coronary atherosclerosis in this study. More studies with larger sample sizes remain necessary to verify whether any correlation exists.

    Matched MeSH terms: Coronary Angiography/methods
  3. Abdullah KA, McEntee MF, Reed W, Kench PL
    J Med Imaging Radiat Oncol, 2016 Aug;60(4):459-68.
    PMID: 27241506 DOI: 10.1111/1754-9485.12473
    The aim of this systematic review is to evaluate the radiation dose reduction achieved using iterative reconstruction (IR) compared to filtered back projection (FBP) in coronary CT angiography (CCTA) and assess the impact on diagnostic image quality. A systematic search of seven electronic databases was performed to identify all studies using a developed keywords strategy. A total of 14 studies met the criteria and were included in a review analysis. The results showed that there was a significant reduction in radiation dose when using IR compared to FBP (P  0.05). The mean ± SD difference of image noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were 1.05 ± 1.29 HU, 0.88 ± 0.56 and 0.63 ± 1.83 respectively. The mean ± SD percentages of overall image quality scores were 71.79 ± 12.29% (FBP) and 67.31 ± 22.96% (IR). The mean ± SD percentages of coronary segment analysis were 95.43 ± 2.57% (FBP) and 97.19 ± 2.62% (IR). In conclusion, this review analysis shows that CCTA with the use of IR leads to a significant reduction in radiation dose as compared to the use of FBP. Diagnostic image quality of IR at reduced dose (30-41%) is comparable to FBP at standard dose in the diagnosis of CAD.
    Matched MeSH terms: Coronary Angiography/methods*; Computed Tomography Angiography/methods*
  4. Givehchi S, Safari MJ, Tan SK, Md Shah MNB, Sani FBM, Azman RR, et al.
    Phys Med, 2018 Jan;45:198-204.
    PMID: 29373248 DOI: 10.1016/j.ejmp.2017.09.137
    PURPOSE: Accurate determination of the bifurcation angle and correlation with plaque buildup may lead to the prediction of coronary artery disease (CAD). This work evaluates two techniques to measure bifurcation angles in 3D space using coronary computed tomography angiography (CCTA).

    MATERIALS AND METHODS: Nine phantoms were fabricated with different bifurcation angles ranging from 55.3° to 134.5°. General X-ray and CCTA were employed to acquire 2D and 3D images of the bifurcation phantoms, respectively. Multiplanar reformation (MPR) and volume rendering technique (VRT) were used to measure the bifurcation angle between the left anterior descending (LAD) and left circumflex arteries (LCx). The measured angles were compared with the true values to determine the accuracy of each measurement technique. Inter-observer variability was evaluated. The two techniques were further applied on 50 clinical CCTA cases to verify its clinical value.

    RESULTS: In the phantom setting, the mean absolute differences calculated between the true and measured angles by MPR and VRT were 2.4°±2.2° and 3.8°±2.9°, respectively. Strong correlation was found between the true and measured bifurcation angles. Furthermore, no significant differences were found between the bifurcation angles measured using either technique. In clinical settings, large difference of 12.0°±10.6° was found between the two techniques.

    CONCLUSION: In the phantom setting, both techniques demonstrated a significant correlation to the true bifurcation angle. Despite the lack of agreement of the two techniques in the clinical context, our findings in phantoms suggest that MPR should be preferred to VRT for the measurement of coronary bifurcation angle by CCTA.

    Matched MeSH terms: Coronary Angiography/methods*; Computed Tomography Angiography/methods*
  5. Borhanuddin BK, Abdul Latiff H, Mohamed Yusof AK
    Cardiol Young, 2022 Dec;32(12):1994-1998.
    PMID: 35707919 DOI: 10.1017/S1047951122000154
    BACKGROUND: CT is an accepted non-invasive imaging tool to assess the coronary arteries in adults; however, its utilisation in children is limited by high heart rate and lack of standardised protocol. We sought to assess diagnostic quality and factors that affect image quality of CT in assessing coronary artery lesions in Kawasaki patients less than 18 years of age.

    METHODOLOGY: CT coronary angiography was performed on patients with Kawasaki disease diagnosed with coronary aneurysm or suspected to have coronary stenosis. Studies were performed using electrocardiogram-gated protocols. General anaesthesia was used in patients who were not cooperative for breathing control. Heart rate, image quality, and effective radiation dose were documented.

    RESULTS: Fifty-two Kawasaki patients underwent CT coronary angiography to assess coronary artery lesions. Median heart rate was 88 beats per minute (range 50-165 beats/minute). Image quality was graded as excellent in 34 (65%) patients, good in 17 (32%), satisfactory in 1, and poor in 1 patient. Coronary artery aneurysm was found in 25 (bilateral = 6, unilateral = 19, multiple = 11). Thrombus was found in 11 patients resulting in partial and total occlusion in 8 and 3 patients, respectively. Coronary stenosis was noted in 2 patients. The effective radiation dose was 1.296 millisievert (median 0.81 millisievert). Better diagnostic imaging quality was significantly related to lower heart rate (p = 0.007).

    CONCLUSION: Electrocardiogram-triggered CT coronary angiography provides a good diagnostic assessment of coronary artery lesions in children with Kawasaki disease.

    Matched MeSH terms: Coronary Angiography/methods; Computed Tomography Angiography/methods
  6. Vattoth S, Cherian J, Pandey T
    Magn Reson Imaging, 2007 Oct;25(8):1227-31.
    PMID: 17442526
    Magnetic resonance angiographic evaluation of the intracranial vasculature has been predominantly carried out using conventional angiographic techniques such as time of flight and phase contrast sequences. These techniques have good spatial resolution but lack temporal resolution. Newer faster angiographic techniques have been developed to circumvent this limitation. Elliptical centric time-resolved imaging of contrast kinetics (EC-TRICKS) is one such technique which has combined the use of elliptical centric ordering of the k-space with multiphase 3D digital subtraction MR angiogram (MRA) to achieve excellent temporal resolution of the arterial and venous circulations. Its applications have been mainly in the peripheral vasculature. We report the use of this technique in a case of a high-flow, direct carotid-cavernous fistula to demonstrate its potential in intracranial MR angiography.
    Matched MeSH terms: Magnetic Resonance Angiography/methods*
  7. Khor CG, Tan BE, Kan SL, Tsang EE, Lim AL, Chong EY, et al.
    J Clin Rheumatol, 2016 Jun;22(4):194-7.
    PMID: 27219306 DOI: 10.1097/RHU.0000000000000362
    OBJECTIVE: There is paucity of data for Takayasu arteritis (TAK) among South Asians. We aimed to evaluate the clinical features, angiographic findings, as well as treatment and outcome of TAK among Malaysian multiethnic groups.

    METHODS: This is a retrospective review of 40 patients with TAK seen in major rheumatology centres in Malaysia between April 2006 and September 2013.

    RESULTS: Majority were female patients (92.5%), with a female-to-male ratio of 12:1. Median duration of disease from diagnosis was 66 months (interquartile range, 33-177 months). Fifteen (37.5%) were Malays, 9 (22.5%) each were Indians and indigenous from East Malaysia and 7 (17.5%) were Chinese. Indian and indigenous from East Malaysia were overrepresented in this disease. The mean (SD) age of symptom onset and diagnosis were 25.5 (8.1) and 27.4 (8.4), respectively. The 3 most common clinical presentations at diagnosis were diminished or absent pulse, which occurred in 80% of the patients, followed by blood pressure discrepancy (60%) and arterial bruit (52.5%). There was no difference in clinical presentation among ethnic groups. The subclavian artery was the commonest vessel involved (72.5%), followed by the carotid artery (65%) and renal artery (47.5%). Eight patients had coronary artery involvement, and 2 patients had pulmonary artery involvement. Type I arterial involvement was the commonest (80.0%), followed by type IV (35%), present in isolation or mixed type. Glucocorticoid was the main medical treatment (90.0%). Nineteen patients (47.5%) underwent revascularization procedures. Five patients died during the follow-up period.

    CONCLUSIONS: The Malaysian TAK cohort had similarities with and differences from other published TAK cohort. A nationwide TAK registry is needed to determine the prevalence of the disease among different ethnic groups.
    Matched MeSH terms: Angiography/methods
  8. Lam ES
    Med J Malaysia, 1979 Dec;34(2):171-3.
    PMID: 548723
    Matched MeSH terms: Cerebral Angiography/methods*
  9. Salah H, Tamam N, Rabbaa M, Abuljoud M, Zailae A, Alkhorayef, et al.
    Appl Radiat Isot, 2023 Feb;192:110548.
    PMID: 36527854 DOI: 10.1016/j.apradiso.2022.110548
    Computed tomography coronary angiography (CTCA) has generated tremendous interest over the past 20 years by using multidetector computed tomography (MDCT) because of its high diagnostic accuracy and efficacy in assessing patients with coronary artery disease. This technique is related to high radiation doses, which has raised serious concerns in the literature. Effective dose (E, mSv) may be a single parameter meant to reflect the relative risk from radiation exposure. Therefore, it is necessary to calculate this quantity to point to relative radiation risk. The objectives of this study are to evaluate patients' exposure during diagnostic CCTA procedures and to estimate the risks. Seven hundred ninety patients were estimated during three successive years. The patient's exposure was estimated based on a CT device's delivered radiation dose (Siemens Somatom Sensation 64 (64-MDCT)). The participating physicians obtained the parameters relevant to the radiation dose from the scan protocol generated by the CT system after each CCTA study. The parameters included the volume CT dose index (CTDIvol, mGy) and dose length product (DLP, mGy × cm). The mean and range of CTDIvol (mGy) and DLP (mGy × cm) for three respective year was (2018):10.8 (1.14-77.7) and 2369.8 ± 1231.4 (290.4-6188.9), (2019): 13.82 (1.13-348.5), and 2180.5 (501.8-9534.5) and (2020) 10.9 (0.7-52.9) and 1877.3 (149.4-5011.1), respectively. Patients' effective doses were higher compared to previous studies. Therefore, the CT acquisition parameter optimization is vital to reduce the dose to its minimal value.
    Matched MeSH terms: Coronary Angiography/methods
  10. Sun CZ, Sim SSKP, Vyas CH, Lott PW, Gunatheesan R, Teo KYC, et al.
    Eye (Lond), 2022 Jun;36(6):1143.
    PMID: 35046551 DOI: 10.1038/s41433-021-01859-6
    Matched MeSH terms: Fluorescein Angiography/methods
  11. Pee XK, Low A, Ab Kahar MEPI, Mohamed SO, Chong YJ
    BMC Ophthalmol, 2023 Nov 07;23(1):444.
    PMID: 37932684 DOI: 10.1186/s12886-023-03186-8
    BACKGROUND: To report a rare case of pulmonary and ocular complications with visual loss due to bilateral Purtscher-like retinopathy and paracentral acute middle maculopathy (PAMM) following a hyaluronic acid (HA) filler injection to the breast. Systemic and visual recovery was attained following corticosteroid therapy.

    CASE PRESENTATION: A 27-year-old lady presented with painless blurring of vision in both eyes for 2 weeks following hyaluronic acid breast filler injections by a non-medical practitioner. She was initially admitted to the medical ward for diffuse alveolar haemorrhage and altered sensorium. The presenting visual acuity was counting fingers in both eyes. Bilateral dilated fundus examination showed hyperaemic discs, concentric rim of retinal whitening around macula with patches of polygonal-shaped retinal whitening, generalised cotton-wool spots, tortuous veins, and flame-shaped haemorrhages. Spectral-domain optical coherence tomography (SD-OCT) macula revealed hyper-reflective bands at the inner nuclear layer (INL). Fluorescein angiography demonstrated hot discs, delayed arm-to-retina time, arterial filling, and arterio-venous transit time with staining of the vessels at the posterior pole. She was managed with a tapering dose of systemic corticosteroids. The visual acuity improved to 6/12 over 8 weeks with significant anatomical and functional improvement. Dilated fundus examination showed resolution of initial funduscopy findings. The hyper-reflective bands on the OCT had resolved with subsequent thinning of the INL and disorganisation of retinal inner layers.

    CONCLUSION: Filler injections are in increasing demand and are frequently being performed by non-medical practitioners. Visual loss from non-facial HA fillers is rare. Inadvertent entry of HA into a blood vessel may potentially cause systemic and sight-threatening ocular complications. Good anatomical knowledge and proper injection technique are vital in preventing this unfortunate sequela. There are limited reports on successful visual recovery following various treatment approaches and we hope this case provides valuable insights.

    Matched MeSH terms: Fluorescein Angiography/methods
  12. Yun KE, Chang Y, Rampal S, Zhang Y, Cho J, Jung HS, et al.
    J Clin Gastroenterol, 2018 07;52(6):508-514.
    PMID: 28471937 DOI: 10.1097/MCG.0000000000000824
    GOALS: Because of shared risk factors between clinically manifest cardiovascular disease and colorectal cancer, we hypothesized the coexistence of subclinical atherosclerosis measured by coronary artery calcium (CAC) and colorectal adenoma (CRA) and that these 2 processes would also share common risk factors.

    BACKGROUND: No study has directly compared the risk factors associated with subclinical coronary atherosclerosis and CRA.

    STUDY: This was a cross-sectional study using multinomial logistic regression analysis of 4859 adults who participated in a health screening examination (2010 to 2011; analysis 2014 to 2015). CAC scores were categorized as 0, 1 to 100, or >100. Colonoscopy results were categorized as absent, low-risk, or high-risk CRA.

    RESULTS: The prevalence of CAC>0, CAC 1 to 100 and >100 was 13.0%, 11.0%, and 2.0%, respectively. The prevalence of any CRA, low-risk CRA, and high-risk CRA was 15.1%, 13.0%, and 2.1%, respectively. The adjusted odds ratios (95% confidence interval) for CAC>0 comparing participants with low-risk and high-risk CRA with those without any CRA were 1.35 (1.06-1.71) and 2.09 (1.29-3.39), respectively. Similarly, the adjusted odds ratios (95% confidence interval) for any CRA comparing participants with CAC 1 to 100 and CAC>100 with those with no CAC were 1.26 (1.00-1.6) and 2.07 (1.31-3.26), respectively. Age, smoking, diabetes, and family history of CRC were significantly associated with both conditions.

    CONCLUSIONS: We observed a graded association between CAC and CRA in apparently healthy individuals. The coexistence of both conditions further emphasizes the need for more evidence of comprehensive approaches to screening and the need to consider the impact of the high risk of coexisting disease in individuals with CAC or CRA, instead of piecemeal approaches restricted to the detection of each disease independently.

    Matched MeSH terms: Coronary Angiography/methods; Computed Tomography Angiography/methods
  13. Sabarudin A, Yusof MZ, Mohamad M, Sun Z
    Radiat Prot Dosimetry, 2014 Dec;162(3):316-21.
    PMID: 24255172 DOI: 10.1093/rpd/nct280
    A study on the radiation dose associated with cerebral CT angiography (CTA) and CT perfusion (CTP) was conducted on an anthropomorphic phantom with the aim of estimating the effective dose (E) and entrance skin dose (ESD) in the eyes and thyroid gland during different CTA and CTP protocols. The E was calculated to be 0.61 and 0.28 mSv in CTA with 100 and 80 kV(p), respectively. In contrast, CTP resulted in an estimated E of 2.74 and 2.07 mSv corresponding to 40 and 30 s protocols, respectively. The eyes received a higher ESD than the thyroid gland in all of these protocols. The results of this study indicate that combining both CTA and CTP procedures are not recommended in the stroke evaluation due to high radiation dose. Application of modified techniques in CTA (80 kV(p)) and CTP (30 s) is highly recommended in clinical practice for further radiation dose reduction.
    Matched MeSH terms: Cerebral Angiography/methods*
  14. Abu Bakar N, Abdul Aziz YF, Singh Sandhu R, Fadzli F, Yaakub NA, Krishnasamy S, et al.
    Heart Lung Circ, 2013 Apr;22(4):305-8.
    PMID: 22921797 DOI: 10.1016/j.hlc.2012.07.016
    Pericardial cysts are uncommon mediastinal lesions that are usually congenital in origin. Patients are usually asymptomatic and the cysts are generally discovered on routine radiography for unrelated purposes. This case illustrates a symptomatic presentation of a haemorrhagic pericardial cyst in which radiographic, echocardiographic and multislice (MRI and CT) imaging were performed. The imaging findings were not typical of pericardial cysts leading to a diagnostic quandary despite the varied imaging techniques. In conclusion, it is important to appreciate that the imaging findings of pericardial cysts can be varied. Radiologists and clinicians alike should be aware of this variability.
    Matched MeSH terms: Magnetic Resonance Angiography/methods
  15. Vashu R, Tan S, Wong AS
    J Clin Neurosci, 2009 Jul;16(7):960-2.
    PMID: 19346131 DOI: 10.1016/j.jocn.2008.09.013
    We report on two patients with intra-operative rupture of cerebral aneurysms that were managed by microsuturing. This is one of only a few reports of successful direct repair using suturing. We found that stitching remains an option to repair a tear of a saccular part of an aneurysm and a torn neck of a blister-like aneurysm, and thus this technique can be considered before sacrificing the artery.
    Matched MeSH terms: Angiography/methods
  16. Chang LK, Liew NS, Soh HL, Tan SZ, Wong SH
    Med J Malaysia, 2008 Jun;63(2):131-6.
    PMID: 18942299 MyJurnal
    CT angiography (CTA) is a fast examination performed with a time-optimised contrast injection to enhance the cerebral arteries. Being a new imaging modality in our hospital, evaluation of the effectiveness of 64-row multislice CTA in detecting intracranial aneurysms in ruptured subarachnoid haemorrhage (SAH) cases is necessary. We conducted a descriptive prospective study by recruiting 30 consecutively operated SAH cases from May 2005 until November 2006. CTA findings were studied by radiologist and neurosurgeon and these were compared with operative findings. The sensitivity and specificity of CTA were 94.4% and 97.2% respectively. Approximately half of the patients were scanned within four hours and operated within 24 hours. In conclusion, CTA proves to be highly sensitive and specific in the diagnosis of intracranial aneurysms in our study.
    KEY WORDS: Subarachnoid haemorrhage, Intracranial aneurysm, Computed tomography (CT), CT angiography (CTA), Sarawak
    Matched MeSH terms: Angiography/methods*
  17. Sim KH, Ong TK, Chin SP, Wong M
    Indian Heart J, 2007 Mar-Apr;59(2 Suppl B):B25-32.
    PMID: 19153433
    Matched MeSH terms: Coronary Angiography/methods*
  18. Tan SP, Bux SI, Kumar G, Razack AH, Chua CB, Lee SH, et al.
    Transplant Proc, 2004 Sep;36(7):1914-6.
    PMID: 15518697
    Catheter angiography is traditionally used to determine renal arterial anatomy in live renal donors. Three-dimensional (3D) contrast-enhanced magnetic resonance imaging (MRA) has been suggested as a noninvasive replacement. We assessed the possibility of using MRA in live renal donors in Malaysia.
    Matched MeSH terms: Magnetic Resonance Angiography/methods*
  19. Chee KH, Siaw FS, Chan CG, Chong WP, Imran ZA, Haizal HK, et al.
    Int J Clin Pract, 2005 Jun;59(6):628-31.
    PMID: 15924588
    This single centre study was designed to demonstrate feasibility, safety and efficacy of the Vivant Z stent (PFM AG, Cologne, Germany). Patients with de novo lesion were recruited. Coronary angioplasty was performed with either direct stenting or after balloon predilatation. Repeated angiogram was performed 6 months later or earlier if clinically indicated. Between January to June 2003, a total of 50 patients were recruited (mean age 55.8 +/- 9 years). A total of 52 lesions were stented successfully. Mean reference diameter was 2.77 mm (+/-0.59 SD, range 2.05-4.39 mm) with mean target lesion stenosis of 65.5% (+/-11.6 SD, range 50.1-93.3%). Forty-six lesions (88.5%) were American College of Cardiologist/American Heart Association class B/C types. Direct stenting was performed in 18 (34.6%) lesions. Mean stent diameter was 3.18 mm (+/-0.41 SD, range 2.5-4 mm), and mean stent length was 14.86 mm (+/-2.72 SD, range 9-18 mm). The procedure was complicated in only one case which involved the loss of side branch with no clinical sequelae. All treated lesions achieved Thrombolysis In Myocardial Infarction 3 flow. Mean residual diameter stenosis was 12.2% (+/-7.55 SD, range 0-22.6%) with acute gain of 1.72 mm (+/-0.50 SD, range 0.5-2.8). At 6 months, there was no major adverse cardiovascular event. Repeated angiography after 6 months showed a restenosis rate of 17% (defined as >50% diameter restenosis). Mean late loss was 0.96 mm (+/-0.48 SD) with loss index of 0.61 (+/-0.38 SD). The restenosis rate of those lesions less than 3.0 mm in diameter was 22.2% compared with 6.25% in those lesions more than 3.0 mm in diameter. The Vivant Z stent was shown to be safe and efficacious with low restenosis rate in de novo coronary artery lesion.
    Matched MeSH terms: Coronary Angiography/methods
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