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2.
Indian J Ophthalmol ; 71(8): 3005-3009, 2023 08.
Article in English | MEDLINE | ID: mdl-37530273

ABSTRACT

Purpose: To compare glaucomatous from non-glaucomatous optic atrophy using optical coherence tomography (OCT) based on the measurement values of Bruch's membrane opening minimum rim width (BMO-MRW), which is a difficult task otherwise due to their varied course of disease progression, treatment protocols, and systemic association to visual impairment. Methods: This study was conducted in 40 eyes, comprising 20 eyes with non-glaucomatous optic neuropathy (NGON) and 20 eyes with glaucomatous optic neuropathy (GON). All patients underwent a complete ophthalmic examination followed by an OCT optic disc scan to calculate the measurement of BMO-MRW. Results: The 5-fold cross-validated area under the curve for GON versus NGON from logistic regression models was 0.95 (95% confidence interval [CI]: 0.86-1.00) using BMO-MRW values from all sectors. The results revealed that the measurements were significantly lesser in GON than in NGON patients. Conclusion: Hence, OCT-based BMO-MRW values could be used as an additional test to compare glaucomatous with non-glaucomatous optic neuropathy patients, especially in cases of high clinical suspicion.


Subject(s)
Glaucoma , Optic Nerve Diseases , Humans , Tomography, Optical Coherence/methods , Bruch Membrane , Intraocular Pressure , Retinal Ganglion Cells , Visual Fields , Nerve Fibers , Glaucoma/diagnosis , Optic Nerve Diseases/diagnosis
3.
Indian J Ophthalmol ; 70(2): 448-452, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35086214

ABSTRACT

PURPOSE: To assess the retinal manifestations of Parkinson's disease using optical coherence tomography. METHODS: A prospective case-control study comparing 30 eyes from 15 patients with Parkinson's disease and 22 eyes from 11 healthy age-matched controls. Total macular subfield thickness and the thickness of the ganglion cell layer, nerve fiber layer, and peripapillary retinal nerve fiber layer were measured with spectral-domain optical coherence tomography (SD-OCT). RESULTS: The mean age of PD patients was 68.4 years ± 10.64 (range: 46-82) and in the control group was 66.36 ± 5.22 (range: 64-68). The average disease duration in patients with PD was 6.7 ± 2.8 years (range: 2-10 years). The mean best-corrected visual acuity in PD was 20/26 and 20/20 in controls, with P = 0.0059, which was significant. Significant difference was also found in the contrast sensitivity between both groups. Structural differences in the central macular thickness (P = 0.0001), subfield thicknesses in the superior (P = 0.003), inferior (P = 0.001), nasal (P = 0.004), and temporal subfields (P = 0.017) was seen. Severe thinning of the ganglion cell layer was seen in PD patients (P = 0.000) as well as of the nerve fiber layer (P = 0.004). Peripapillary retinal nerve fiber thickness measured showed significant thinning in superotemporal (P = 0.000), superonasal (P = 0.04), inferonasal (P = 0.000), inferotemporal (P = 0.000), nasal (P = 0.000), and temporal quadrants (P = 0.000). CONCLUSION: Visual dysfunction was observed in patients with PD along with structural alterations on OCT, which included macular volumes, ganglion cell layer, and peripapillary retinal nerve fiber layer.


Subject(s)
Parkinson Disease , Tomography, Optical Coherence , Aged , Case-Control Studies , Humans , Nerve Fibers , Parkinson Disease/complications , Parkinson Disease/diagnosis , Retinal Ganglion Cells , Tomography, Optical Coherence/methods
4.
Eur J Ophthalmol ; 32(4): 2355-2367, 2022 Jul.
Article in English | MEDLINE | ID: mdl-34615395

ABSTRACT

PURPOSE: To describe the etiology and treatment outcomes of choroidal neovascularization (CNV) in a pediatric population with intravitreal anti-vascular endothelial growth factors (VEGF). METHODS: Retrospective single center interventional case series. A total of 26 eyes of 23 consecutive pediatric patients with CNV of various etiologies were treated with intravitreal injection of anti-VEGF agents. RESULTS: There were 15 males (65.2%) and eight females (34.8%), diagnosed with CNV during the study period. The mean age at presentation with CNV was 11.7 ± 3.3 years, (range 4-16 years) and the mean follow was 28.1 ± 18 months, (range 8-72 months). Inflammatory CNV was the most common etiology. The mean best corrected visual acuity (BCVA) and mean central macular thickness (CMT) at presentation, were logMAR 0.8 ± 0.3 and 367.6 ± 134.8 µm respectively. At the final visit, CNV in all eyes remained regressed with significant improvement in mean BCVA to logMAR 0.4 ± 0.4 (p < 0.0001) and mean CMT to 242.5 ± 82.4 µm (p < 0.0001). A mean of two intravitreal injections per eye was required for CNV regression. CONCLUSION: Intravitreal anti-VEGF therapy for pediatric CNV is an effective treatment in majority of affected eyes.


Subject(s)
Angiogenesis Inhibitors , Choroidal Neovascularization , Adolescent , Angiogenesis Inhibitors/therapeutic use , Bevacizumab/therapeutic use , Child , Child, Preschool , Choroidal Neovascularization/diagnosis , Choroidal Neovascularization/drug therapy , Choroidal Neovascularization/etiology , Female , Fluorescein Angiography , Humans , Intravitreal Injections , Male , Retrospective Studies , Treatment Outcome , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Visual Acuity
5.
Eur J Ophthalmol ; 32(3): 1610-1618, 2022 May.
Article in English | MEDLINE | ID: mdl-34132140

ABSTRACT

PURPOSE: To describe an unusual variant of central serous chorioretinopathy (CSC) presenting as a choroidal elevation with subretinal fluid and its response to accepted treatment modalities of CSC. DESIGN: A retrospective case series. SUBJECTS: Six eyes of three patients, two males and one female, with a mean age of 55.3 years, were included in the study. All of them had Pachychoroid features, solitary choroidal elevation and subretinal fluid on optical coherence tomography (OCT); none of the patients had a previous episode of CSC. METHODS: Patients were studied with biomicroscopy, ultrasonography, fluorescein angiography and indocyanine green angiography. Systemic evaluation to rule out inflammatory and infective pathologies, and an oncologist referral also was done. Patients were managed in the line of central serous chorioretinopathy, using conservative treatment, focal laser and oral eplerenone. MAIN OUTCOME MEASURES: Resolution of subretinal fluid and choroidal elevation. RESULTS: Complete resolution of choroidal elevation and subretinal fluid was noted in all the three patients. There was no recurrence till the end of follow-up. CONCLUSION: Pachychoroid disease may present as solitary choroidal elevation with subretinal fluid due to exaggerated posterior choroidal fluid loculation and has a favourable outcome. However, it should be considered after exclusion of other differential diagnoses.


Subject(s)
Central Serous Chorioretinopathy , Central Serous Chorioretinopathy/diagnosis , Central Serous Chorioretinopathy/pathology , Choroid/pathology , Female , Fluorescein Angiography/methods , Humans , Male , Phenotype , Retrospective Studies , Tomography, Optical Coherence/methods
6.
Cureus ; 13(3): e14057, 2021 Mar 23.
Article in English | MEDLINE | ID: mdl-33777588

ABSTRACT

Purpose To evaluate the anatomical and visual outcomes in optic disc pit maculopathy following pars plana vitrectomy (PPV) with inverted internal limiting membrane (ILM) flap Methods Retrospective interventional case series of 10 patients diagnosed with serous macular detachment secondary to optic disc pit who underwent PPV with inverted ILM flap and were followed up for a year. Results A p-value of less than 0.05 was defined as statistically significant. The mean age of patients was 27.2 ± 10.6 years, preoperatively the mean best-corrected visual acuity of the logarithm of the minimum angle of resolution was 0.91 ± 0.42 (approximate Snellen equivalent 20/162), which improved to the logarithm of the minimum angle of resolution of 0.58 ± 0.29 (approximate Snellen equivalent 20/76) at end of one year, (p=0.008). The mean central macular thickness was 804.9 ± 294.1 m which improved to 273.4 ± 102.54 m, (p=0.002). After surgery, at end of one year, 60% of patients (6/10) had 15- or more-than-15-letter improvement of vision on Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity testing, 20% (2/10) gained a 10-letter improvement and 20% (2/10) retained the same vision. Conclusion PPV with inverted ILM flap can be considered as a good approach for the management of serous macular detachment secondary to optic disc pit and produce good anatomical and visual results at one year with stabilization of the disease.

7.
Am J Ophthalmol Case Rep ; 22: 101042, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33681533

ABSTRACT

PURPOSE: To describe the multimodal imaging findings and treatment outcomes in choroidal neovascularization secondary to Choroideremia. OBSERVATIONS: A 13-year-old male presented with reduced visual acuity in the left eye. He gave a history of nyctalopia. His best-corrected visual acuity (BCVA) was 20/20 in the right eye and 20/40 in the left eye. Based on multimodal imaging, the diagnosis of choroideremia in both eyes with a subfoveal choroidal neovascularization in the left eye was made. He underwent five intravitreal anti-vascular endothelial growth factor (VEGF) injections of Ranibizumab over a period of 3 years, with the final injection given due to recurrence of neovascularization. Post-treatment, his BCVA improved to 20/20 in the left eye with regression of the neovascular network. CONCLUSIONS AND IMPORTANCE: This case highlights the role of OCTA in diagnosis of choroidal neovascularization in choroideremia as well as its successful management with anti-VEGF injections with long term follow up.

9.
Oman J Ophthalmol ; 11(3): 200-206, 2018.
Article in English | MEDLINE | ID: mdl-30505108

ABSTRACT

Central serous chorioretinopathy (CSC), the fourth most common nonsurgical retinopathy with a usual self-limiting course, is known to present with persistent or recurrent form with distressing visual loss. Evolution of newer mutimodal imaging techniques have revolutionized the understanding about the pathophysiology of CSC, and hence the diagnosis and management. Multifactorial etiopathology of CSC promotes the use of multiple treatment modalities. With advances in investigative options, treatment options including conventional focal laser, micropulse laser, photodynamic therapy, and transpupillary thermotherapy are also advancing and refining. Medical management for CSC is also under evaluation with a wide spectrum of new drugs in vogue. However, standard of treatment is yet to be established through randomized clinical trials. This review article discusses the current approach to multimodal treatment options for CSC including conventional as well as newer therapeutic modalities.

10.
Oman J Ophthalmol ; 11(2): 103-112, 2018.
Article in English | MEDLINE | ID: mdl-29930442

ABSTRACT

Central serous chorioretinopathy (CSC), the fourth most common nonsurgical retinopathy, is characterized by serous retinal detachment most commonly involving the macular region. Although natural history of CSC shows a self-limiting course, patients are known to present with persistent, recurrent, or even bilateral CSC with distressing visual loss. Multimodal imaging techniques for CSC include optical coherence tomography (OCT) with enhanced depth imaging, fundus autofluorescence, fluorescein angiography, indocyanine green angiography, and OCT angiography. Evolution of new imaging techniques in addition to conventional imaging modalities has revolutionized the understanding about the pathophysiology of CSC and hence the diagnosis and management. This review article elaborates on current understanding about pathophysiology and risk factors, as well as multimodal imaging-based features of CSC.

11.
Retina ; 38(6): 1195-1204, 2018 Jun.
Article in English | MEDLINE | ID: mdl-28445211

ABSTRACT

PURPOSE: To study multimodal imaging features of polypoidal choroidal vasculopathy (PCV) associated with central serous chorioretinopathy (CSC) in the same eye. METHODS: A retrospective observational study of cases of suspected PCV which underwent indocyanine green angiography, fundus fluorescein angiography and optical coherence tomography was done, to look for simultaneous typical CSC-like active leak in the same eye. The relevant history, best-corrected visual acuity, optical coherence tomography, fundus fluorescein angiography, and indocyanine green angiography findings were analyzed. RESULTS: From 226 patients reviewed, 195 patients had PCV from which 6 eyes (3.07%) with features of PCV associated with typical CSC-like active leak in the same eye were identified; 3 men and 3 women with a mean age of 62.6 years. Optical coherence tomography showed notched pigment epithelial detachment in two and irregular peaked pigment epithelial detachment in four cases with subretinal fluid and/or subretinal haemorrhage over a thick choroid with dilated outer choroidal vessels. Fundus fluorescein angiography showed stippled hyperfluorescence at polyp area and a separate typical CSC-like active leak-Inkblot in three and Smokestack in three cases. On indocyanine green angiography, multiple polyps were noted with choroidal hyperpermeability in late phase at the site of CSC leak. CONCLUSION: The coexistence of PCV with typical CSC-like active leaks and a thick choroid in the same eye simultaneously provides strong evidence that these diseases have an association and support the hypothesis that these conditions may originate from predisposed thick choroid.


Subject(s)
Central Serous Chorioretinopathy/pathology , Choroid Diseases/pathology , Choroid/blood supply , Aged , Central Serous Chorioretinopathy/diagnostic imaging , Choroid Diseases/diagnostic imaging , Coloring Agents , Female , Fluorescein Angiography/methods , Humans , Indocyanine Green , Male , Middle Aged , Multimodal Imaging , Retinal Detachment/pathology , Retinal Pigment Epithelium/pathology , Retrospective Studies , Subretinal Fluid , Tomography, Optical Coherence/methods
12.
Retina ; 38(7): 1307-1315, 2018 07.
Article in English | MEDLINE | ID: mdl-28520642

ABSTRACT

PURPOSE: To assess the long-term visual and anatomical outcomes after intravitreal anti-vascular endothelial growth factor therapy for inflammatory choroidal neovascular membrane (CNVM). METHODS: Retrospective case series of 15 consecutive cases of newly diagnosed inflammatory CNVM who were treated with intravitreal bevacizumab or ranibizumab injections. RESULTS: The study included 8 women and 7 men with mean age at presentation with CNVM of 40.53 ± 17.46 years (range, 11-70 years), and mean follow-up duration after anti-vascular endothelial growth factor therapy was 20.53 ± 14.53 months (range, 6-48 months). All eyes had classic CNVM confirmed by fluorescein angiography, most commonly located in the peripapillary area (8 eyes, 53.3%), followed by juxtafoveal (4 eyes, 26.7%), and subfoveal location (3 eyes, 20%). All CNVMs showed complete resolution with mean 2.6 ± 1.2 injections per eye. Preinjection mean best-corrected visual acuity of logarithm of minimum angle of resolution 0.79 ± 0.76 (approximate Snellen equivalent 20/123) and mean central macular thickness of 435.9 ± 190.2 µm improved significantly to mean best-corrected visual acuity of logarithm of minimum angle of resolution 0.46 ± 0.43 (approximate Snellen equivalent 20/58) and mean central macular thickness of 262.13 ± 108.70 µm (P value 0.02 and <0.0001, respectively) at the final visit. Recurrence was seen in 26.7% eyes (4/15), all of which regressed with single injection. Only complication noted was subretinal fibrosis in one eye (6.7%). CONCLUSION: For inflammatory CNVM, in addition to immunosuppression in cases with active inflammation, anti-vascular endothelial growth factor therapy seems as a very effective treatment modality resulting in significant visual improvement and foveal flattening. Incidence of major complications is rare, and the recurrence rate seems low.


Subject(s)
Bevacizumab/administration & dosage , Choroidal Neovascularization/drug therapy , Choroiditis/drug therapy , Ranibizumab/administration & dosage , Adolescent , Adult , Aged , Angiogenesis Inhibitors/administration & dosage , Child , Choroidal Neovascularization/diagnosis , Choroiditis/diagnosis , Female , Fluorescein Angiography , Follow-Up Studies , Fundus Oculi , Humans , Intravitreal Injections , Male , Middle Aged , Retrospective Studies , Time Factors , Tomography, Optical Coherence , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Young Adult
13.
Aliment Pharmacol Ther ; 44(2): 189-97, 2016 07.
Article in English | MEDLINE | ID: mdl-27193351

ABSTRACT

BACKGROUND: Periostin is highly expressed in eosinophilic oesophagitis (EoE), but has not been extensively studied as a non-invasive biomarker. AIM: To assess whether serum periostin distinguished EoE from controls at baseline, had utility for monitoring treatment response, or was associated with IL-13 levels. METHODS: This was a sub-analysis of a prospective cohort study of adults undergoing out-patient upper endoscopy. Incident cases of EoE were diagnosed per consensus guidelines. Controls were subjects with either GERD or dysphagia without EoE. EoE patients were treated with swallowed/topical steroids and had repeat endoscopy/biopsy. Serum periostin levels for cases and controls were compared at baseline, and pre/post-treatment levels were compared for cases. Serum IL-13 and tissue expression of periostin were also assessed. RESULTS: A total of 61 incident EoE cases and 87 controls were analysed. Despite a marked increase in tissue periostin expression in cases, the median baseline serum periostin level was only slightly higher in cases than controls (22.1 ng/mL vs. 20.7; P = 0.04); there was no change in post-treatment levels. There was also no difference in serum periostin for cases by histologic response or atopic status. There was a strong trend towards higher serum IL-13 levels in cases in the highest periostin quartile (57.1 pg/mL vs. 2.6; P = 0.07). CONCLUSIONS: Serum periostin levels were similar in cases and controls, and there were no changes post-treatment. Given elevated IL-13 levels in the EoE patients with the highest periostin levels, future studies could explore periostin as a biomarker in EoE, perhaps in the setting of anti-IL-13 therapy.


Subject(s)
Cell Adhesion Molecules/blood , Eosinophilic Esophagitis/diagnosis , Interleukin-13/blood , Adult , Biomarkers/blood , Biopsy , Deglutition Disorders/diagnosis , Endoscopy/methods , Female , Humans , Male , Middle Aged , Outpatients , Prospective Studies
14.
Ophthalmic Surg Lasers Imaging ; 43(4): 284-90, 2012 Jul 01.
Article in English | MEDLINE | ID: mdl-22788581

ABSTRACT

BACKGROUND AND OBJECTIVE: To study the safety and efficacy of "graded" subthreshold transpupillary thermotherapy (TTT), a novel treatment protocol for chronic central serous chorioretinopathy (CSC) and an alternative to photodynamic therapy (PDT). PATIENTS AND METHODS: This retrospective pilot study included 10 eyes with chronic CSC that underwent TTT with 810-nm continuous diode laser treatment using a subthreshold power (60% reduced from threshold) for 60 seconds. Treatment was repeated at 20% increase in power from the baseline if submacular fluid persisted on optical coherence tomography (OCT) after 1 month (graded fashion). RESULTS: The mean chronic CSC duration was 20.3 ± 8.3 months. Eight eyes (80%) showed resolution of CSC on OCT. Mean number of TTT sittings required was 1.5. Although 5 eyes (50%) had 3 or more lines of improvement in Snellen visual acuity, 3 eyes (30%) had up to 2 lines of improvement. None of the patients developed macular burn or scar. CONCLUSION: The safety enhanced graded subthreshold TTT was beneficial in patients with chronic CSC.


Subject(s)
Central Serous Chorioretinopathy/therapy , Hyperthermia, Induced/methods , Adult , Chronic Disease , Fluorescein Angiography , Humans , Hyperthermia, Induced/adverse effects , Lasers, Semiconductor/therapeutic use , Male , Middle Aged , Pilot Projects , Pupil , Retrospective Studies , Tomography, Optical Coherence , Treatment Outcome , Visual Acuity/physiology
15.
Bone Marrow Transplant ; 40(4): 361-4, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17563733

ABSTRACT

Recipients of granulocyte-colony stimulating factor/granulocyte macrophage-colony stimulating factor are not only individuals with underlying disorders, but also healthy donors undergoing peripheral blood progenitor cell (PBPC) mobilization. In addition to the known adverse effects associated with G-CSF, complications such as splenic rupture have also been reported. A review of the English literature, with addition of a patient with plasma cell myeloma, reveals that splenic rupture occurs not only in patients with underlying disease, but also in healthy PBPC donors. Although the cause of splenic rupture does not appear to be associated with any specific condition, physicians should be alerted to the possibility of this potentially fatal complication in individuals receiving G-CSF therapy.


Subject(s)
Granulocyte Colony-Stimulating Factor/adverse effects , Granulocyte-Macrophage Colony-Stimulating Factor/adverse effects , Hematopoietic Stem Cell Mobilization/adverse effects , Multiple Myeloma/therapy , Splenic Rupture/etiology , Hematopoietic Stem Cell Mobilization/methods , Humans , Male , Middle Aged , Tissue Donors
18.
Clin Chim Acta ; 348(1-2): 131-7, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15369746

ABSTRACT

BACKGROUND: Lipid peroxidation and derived oxidized products are being intensively investigated because of their potential to cause injury and because of their pathogenic role in several diseases. The view that an excess of lipid peroxidation products is present and is relevant in the pathogenesis of cardiogenic shock-induced damage has still not received definitive support. METHODS: To evaluate the extent of lipid peroxidation, the status of enzymatic and nonenzymatic antioxidants in patients with cardiogenic shock that complicate acute myocardial infarction (AMI) and to compare with normal subjects. RESULTS: Compared with normal subjects, cardiogenic shock patients had higher malondialdehyde, conjugated dienes and reduced activities of erythrocyte antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lower concentrations of reduced glutathione (GSH) in erythrocyte and in plasma GSH, vitamin C, vitamin E and in beta-carotene. CONCLUSIONS: Cardiogenic shock is associated with greater than normal lipid peroxidation and with an imbalance in antioxidants' status. These results indicate that low activities of SOD, CAT, GPx and low concentrations of GSH, vitamin C, vitamin E and beta-carotene in the circulation of patients with cardiogenic shock complicating AMI may be due to increased utilization to scavenge lipid peroxides. Decrease in plasma concentrations of GSH, vitamin E and beta-carotene seems to be responsible for the elevation of lipid peroxidation in cardiogenic shock complicating AMI compared with MI.


Subject(s)
Antioxidants/metabolism , Myocardial Infarction/metabolism , Oxidative Stress , Shock, Cardiogenic/metabolism , Ascorbic Acid/blood , Blood Pressure , Catalase/blood , Female , Glutathione/blood , Glutathione Peroxidase/blood , Heart Rate , Humans , Male , Middle Aged , Myocardial Infarction/complications , Myocardial Infarction/physiopathology , Shock, Cardiogenic/etiology , Shock, Cardiogenic/physiopathology , Superoxide Dismutase/blood , Thiobarbituric Acid Reactive Substances/metabolism , Vitamin E/blood , beta Carotene/blood
19.
Clin Chim Acta ; 340(1-2): 207-12, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14734214

ABSTRACT

BACKGROUND: Free radical-mediated oxidative stress has been implicated in the progression of alcoholic hypertension and diabetic hypertension. METHODS: The lipid peroxides and antioxidant status of plasma and erythrocytes were investigated in alcoholic hypertensive patients and alcoholic hypertensive patients with diabetes and compared with normal subjects. RESULTS: A significant increase is observed in the levels of glucose, lipid peroxidation (P<0.05) in the alcoholic hypertensive patients with/without diabetes and the increase was significantly higher in alcoholic hypertensive patients with diabetes. The activities of erythrocyte antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH) and plasma concentrations of GSH, vitamin C, vitamin E and beta-carotene decreased significantly and the level of ceruloplasmin increased in alcoholic hypertensive patients with/without diabetes when compared to normal subjects. Plasma GSH and vitamin E levels exhibited a further decrease in alcoholic hypertensive patients with diabetes. CONCLUSIONS: An enhanced lipid peroxidation is observed in alcoholic hypertensive patients with diabetes and a more pronounced decrease in the levels of plasma GSH and vitamin E among antioxidants.


Subject(s)
Alcoholism/complications , Alcoholism/metabolism , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/metabolism , Hypertension/complications , Hypertension/metabolism , Lipid Peroxidation , Adult , Alcoholism/blood , Antioxidants/metabolism , Blood Glucose/metabolism , Blood Pressure/physiology , Diabetes Mellitus, Type 2/blood , Erythrocytes/enzymology , Erythrocytes/metabolism , Humans , Hypertension/blood , Lipid Peroxides/metabolism , Middle Aged , Oxidation-Reduction
20.
Br J Radiol ; 54(639): 232-40, 1981 Mar.
Article in English | MEDLINE | ID: mdl-7470785

ABSTRACT

During 1978/79 a survey was made of the performance characteristics of 29 EMI brain and body CT scanners in Britain. Comparative data on such performance parameters as noise, uniformity of CT numbers, low-contrast detectability, resolution, modulation transfer function (MTF) and effective photon energy were measured using a set of regular-geometry and anthropomorphic phantoms. In addition, dose profiles were obtained for a single slice using TLD and film. The results of the survey are presented; the dependence of the performance characteristics on the types of machines surveyed and the operating modes employed is discussed.


Subject(s)
Tomography, X-Ray Computed , Brain/diagnostic imaging , Humans , Models, Structural , Radiation Dosage , Technology, Radiologic , Tomography, X-Ray Computed/instrumentation , Tomography, X-Ray Computed/methods , United Kingdom
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