AIM: To determine the frequency of HIV-related ocular involvement and to describe the characteristics of involvement in a special clinic in Tehran.METHODS: In this cross sectional study, 141 patients (125 male and 16 female, 282 eyes) of HIV-infected patients with various stages of HIV infection that were referred to Center of behavioral diseases were evaluated during a period of 7 months. Every patient had a complete profile including demographic data, method of HIV transmission, recent CD4 T cell lymphocyte count, serological studies for common sexual or blood-born viruses and toxoplasmosis, history of antiretroviral therapy, and associated systemic disease. RESULTS: A total of 141 patients were evaluated. HIV-related ocular involvement was detected in 15 patients (10.6%), including 3 mycobacterium tuberculosis-related choroiditis, 2 cytomegalovirus retinitis, 2 retinal toxoplasmosis, 2 herpes simplex virus-related lesions, 1 HIV-associated retinopathy, 1 herpes zoster ophthalmicus, 1 undetermined vitritis, and 3 cases of cranial nerve involvement including 2 cases of gaze palsy and 1 case of papilitis. In our study, mean CD4 T cell lymphocyte count was fewer in patients with ocular involvement than in patients without ocular involvement (204.7±123.8 vs 403.7±339.7, P=0.029), but there was no difference in other possible associated factors between two groups.lesions are the most common HIV-related ocular involvements in Tehran that is different from those of recent publications in developed countries.

Purpose: This study aimed to evaluate the impact of a metal artifact reduction (MAR) algorithm on cone-beam computed tomography (CBCT) scans of titanium and zirconia implants, both within and outside the field of view (FOV). Materials and Methods: In this in vitro study, a dry human mandible was positioned in a CBCT scanner with only its left quadrant included in the FOV. Each type of implant (titanium and zirconia) was placed once in the right second premolar extraction socket and once in the left second premolar extraction socket of the mandible. CBCT scans were acquired with and without MAR. Three regions of interest (ROIs) were defined in relation to a resin block, and the contrast-to-noise ratio (CNR) was calculated for each ROI. Data were analyzed using 2-way analysis of variance with an alpha level of 0.05. Results: Application of a MAR algorithm significantly increased the CNR within and outside the FOV for both implant types (P<0.05). Relative to titanium implants, zirconia implants were associated with significantly lower CNRs in both positions (P<0.05) and generated more artifacts. Implant placement outside the FOV was associated with slightly lower image quality than positioning within the FOV, although this finding was not significant (P>0.05). Conclusion The results suggest that application of a MAR algorithm in CBCT significantly impacts artifactgeneration. Titanium implants exhibited significantly lower metal artifact generation compared to zirconia implants.Positioning either implant type outside the FOV, as opposed to inside it, slightly increased artifact generation;however, this was not statistically significant.

Purpose: This study aimed to evaluate the impact of a metal artifact reduction (MAR) algorithm on cone-beam computed tomography (CBCT) scans of titanium and zirconia implants, both within and outside the field of view (FOV). Materials and Methods: In this in vitro study, a dry human mandible was positioned in a CBCT scanner with only its left quadrant included in the FOV. Each type of implant (titanium and zirconia) was placed once in the right second premolar extraction socket and once in the left second premolar extraction socket of the mandible. CBCT scans were acquired with and without MAR. Three regions of interest (ROIs) were defined in relation to a resin block, and the contrast-to-noise ratio (CNR) was calculated for each ROI. Data were analyzed using 2-way analysis of variance with an alpha level of 0.05. Results: Application of a MAR algorithm significantly increased the CNR within and outside the FOV for both implant types (P<0.05). Relative to titanium implants, zirconia implants were associated with significantly lower CNRs in both positions (P<0.05) and generated more artifacts. Implant placement outside the FOV was associated with slightly lower image quality than positioning within the FOV, although this finding was not significant (P>0.05). Conclusion The results suggest that application of a MAR algorithm in CBCT significantly impacts artifactgeneration. Titanium implants exhibited significantly lower metal artifact generation compared to zirconia implants.Positioning either implant type outside the FOV, as opposed to inside it, slightly increased artifact generation;however, this was not statistically significant.

Purpose: This study aimed to evaluate the impact of a metal artifact reduction (MAR) algorithm on cone-beam computed tomography (CBCT) scans of titanium and zirconia implants, both within and outside the field of view (FOV). Materials and Methods: In this in vitro study, a dry human mandible was positioned in a CBCT scanner with only its left quadrant included in the FOV. Each type of implant (titanium and zirconia) was placed once in the right second premolar extraction socket and once in the left second premolar extraction socket of the mandible. CBCT scans were acquired with and without MAR. Three regions of interest (ROIs) were defined in relation to a resin block, and the contrast-to-noise ratio (CNR) was calculated for each ROI. Data were analyzed using 2-way analysis of variance with an alpha level of 0.05. Results: Application of a MAR algorithm significantly increased the CNR within and outside the FOV for both implant types (P<0.05). Relative to titanium implants, zirconia implants were associated with significantly lower CNRs in both positions (P<0.05) and generated more artifacts. Implant placement outside the FOV was associated with slightly lower image quality than positioning within the FOV, although this finding was not significant (P>0.05). Conclusion The results suggest that application of a MAR algorithm in CBCT significantly impacts artifactgeneration. Titanium implants exhibited significantly lower metal artifact generation compared to zirconia implants.Positioning either implant type outside the FOV, as opposed to inside it, slightly increased artifact generation;however, this was not statistically significant.