Distribution and prevalence of refractive error in Iranian adult population results of the PERSIAN eye cohort study PECS.

The Persian Eye Cohort Study, a population-based cross-sectional study from 2015 to 2020, examined refractive error prevalence among 48,618 Iranian adults aged 31 to 70. The study encompassed six centers in Iran, employing random cluster sampling for demographic, medical, and socioeconomic data collection through interviews. Ophthalmic exams included visual acuity, automated and manual objective refraction, subjective refraction, slit lamp, and fundus examinations. Using the spherical equivalent definition, the sample population was categorized into groups. Results indicated a mean age of 49.52 ± 9.31 and a mean refractive error of 0.26 diopters (D) ± 1.6 SD (95% CI - 0.27 to -0.24), ranging from -26.1 to + 18.5 SD. Prevalence of myopia (< -0.5D) and hyperopia (> + 0.5D) was 22.6% (95% CI 22.2-23%) and 12.5% (95% CI 12.1-12.8%), respectively. Regarding different age groups, the prevalence of hyperopia and astigmatism exhibited a steady and significant rise with increasing age (p-value < 0.001 for both). The prevalence of Myopia, however, showed a distinctive pattern, initially increasing in adults under 45, declining in those aged 55-64, and rising again among individuals aged 60 and older. Female gender, older age, urban residency, higher education, higher income, and Fars ethnicity were significantly related to a higher prevalence of myopia (p-value < 0.001 for all). Female gender (p-value < 0.001), aging (p-value < 0.001), urban residency (p-value = 0.029), and lower-income (p-value = 0.005) were significantly related to higher prevalence of hyperopia. Astigmatism (> 1D) was prevalent in 25.5% of participants (95% CI 25.1-25.9%) and correlated with male gender, aging, urban residency, illiteracy, and higher income (p-value < 0.001, < 0.001, < 0.001, < 0.001, 0.014, respectively). The study's comparison with regional and international surveys highlighted the increase in myopia among those over 65 due to higher nuclear cataract rates in older adults. Myopia positively related to education, income, and urban residency, while hyperopia did not exhibit such associations.

Balance measures of mini and brief balance evaluation system tests for Iranian population.

Introduction: Falling is a serious problem for all ages. There are several tests to assess balance. Mini-BESTest and brief-BESTest are balance tests for which there are no normative values for Iranian people. We aimed to provide the normative values of mini-BESTest and brief-BESTest among healthy Iranian adults. Methods: A cross-sectional study was designed. Three hundred healthy adults (150 males and 150 females) in six age groups (18-29, 30-39, 40-49, 50-59, 60-69, +70 years) completed the tests using Persian mini-BESTest and brief-BESTest. Normative values were calculated for age groups. Results: Normative values of mini-BESTest and brief- BESTest decreased significantly with age (from 27 to 21.9 for mini-BESTest and from 22.9 to 15.4 for brief BESTest). There were no significant differences between genders except for females in 30-39 and 40-49 years age groups which scored better on brief-BESTest and mini-BESTest, respectively. Males had significantly scored better in brief- BESTest in 60-69 and ≥ 70 age groups. Conclusions: The normative values of the mini-BESTest and brief-BESTest provided for healthy Iranian adults can help clinicians when assessing subjects with balance dysfunction.

Evaluation of the effect of artificial tears on corneal epithelial thickness changes after photorefractive keratectomy.

PURPOSE: This study aimed to evaluate the corneal epithelial thickness changes after photorefractive keratectomy (PRK) and the impact of long-term artificial tear usage on epithelial thickness changes in these patients. METHODS: This study was performed on 71 patients (142 eyes) without dry eye disease who received PRK for myopic refractive correction. The corneal epithelial thickness profile was obtained before, one, three, and six months after surgery using anterior segment optical coherence tomography. Patients were randomly divided into two groups: group A, who received preservative-free artificial tears post-surgery, and group B, who did not receive artificial tears. RESULTS: The epithelial thickness decreased universally in the first month and then increased in the 3- and 6-month follow-ups. Group A had a significantly thicker epithelium in central, paracentral, and midperipheral zones compared with group B in the 3-month follow-up. In the 6-month follow-up, no significant differences were detected between groups. At the last follow-up, the central, paracentral, and midperipheral zone epithelial thicknesses in all patients were significantly higher than preoperative values, but peripheral zone thickness only increased to preoperative values. CONCLUSIONS: Patients using artificial tears showed a faster thickening, especially in the central and paracentral zones, but there were no significant differences between the two groups in the final follow-up. Artificial tear usage may increase the rate of the epithelial remodeling process in post-PRK patients without significantly altering the final epithelial thickness profile. Further studies are warranted to evaluate the influence of different factors on epithelial remodeling.

Jugular foramen versus hypoglossal canal in axial CT scan.

Background: Differentiating jugular foramen from hypoglossal canal in computed tomography (CT) scan is vital for correct diagnosis of posterior fossa pathologies; however, it has been shown that the ability for differentiating these skull base elements is limited. The purpose of this study was to produce a simple algorithm for differentiating the jugular foramen from the hypoglossal canal in axial CT scan on two levels (top level where bony carotid canal is evident and lower level where bony carotid canal is not evident). Methods: Data derived from axial CT scan of 250 patients (500 sides) were used for producing algorithm. At top level petro-occipital fissure utilized for recognizing occipital condyle in which hypoglossal canal is located; and, at lower level the distance between the posterior border of the anatomic element (jugular foramen or hypoglossal canal) and the tangent to the anterior bony part is used for producing algorithm. Results: The mean age of patients was 38.1 ± 19 years. The petro-occipital fissure can be used in all patients for differentiating hypoglossal canal. At lower level the distance between the anterior tangent and the posterior border of the element was significantly lower for hypoglossal canal (P value < 0.001). The distance more than 3.5 mm with sensitivity 83.8% and specificity 97.1% differentiate jugular foramen from hypoglossal canal. Conclusion: Simple algorithms based on quantitative morphologic features of the jugular foramen and hypoglossal canal can be used with high sensitivity and specificity to distinguish these elements.

Presumably Corneal Graft Rejection after COVID-19 Vaccination.

We report two cases of corneal graft rejection following immunization with COVID-19-inactivated vaccine Sinopharm and describe the practical implications of this phenomenon in the clinical setting. A 36-year-old woman with a history of unilateral repeated PKP received the first dose of inactivated Sinopharm vaccine. Seven days later, she presented with symptoms and signs of unilateral corneal graft rejection on slit-lamp examination. A 54-year-old woman with a history of unilateral PKP secondary to herpes simplex keratitis (HSK) developed signs of unilateral corneal graft rejection just a week after injection of the first dose of the similar vaccine. Rejection in both patients was treated successfully with topical steroids. To the best of our knowledge, this is the first report of corneal graft rejection following the COVID-19-inactivated Sinopharm vaccine which occurred through the short period after the injection. We hypothesized that the rejection is the result of an allogenic reaction and the immunogenic role of aluminum hydroxide as an adjuvant of this type of vaccine. However, as the second case had a history of rejection following the HSK, a reactivation could not be definitely ruled out. Ophthalmologists should consider these types of adverse reactions after COVID-19 immunization and also monitor a close follow-up of graft health postimmunization. Patients should be informed about the signs and symptoms of rejection, urgent referral, and treatment.

Normative values of functional reach test, single-leg stance test, and timed "UP and GO" with and without dual-task in healthy Iranian adults: A cross-sectional study.

Background: Balance impairment is a common problem in all age groups. There are several tools to assess balance. Functional reach test (FRT), single-leg stance (SLS) test, timed up and go (TUG) test, and TUG with the cognitive dual-task (TUGcog) are commonly employed balance tests. The current study aimed to determine the normative values of FRT, SLST, TUG, and TUGcog across age groups and genders in healthy Iranian adults. Methods: We designed a cross-sectional study, and 240 healthy adults (120 males and 120 females) in six age groups (18-29, 30-39, 40-49, 50-59, 60-69, ≥70 years) completed FRT, SLST, TUG, and TUGcog based on the Persian version of BESTest instructions. Results: There were significant age-specific declines in balance performances. Gender had effects on 18-29 years and older adults (≥60 years), and males performed better than females. Male and females had similar performance on the TUG and TUGcog tests in 60-69 years (p > 0.05). Conclusions: The normative values of FRT, SLS, TUG, and TUGcog provided for healthy Iranian adults increase the clinical utility of tests, and serve as a reference to estimating the individuals' balance performance across age and gender groups.

Ectopic intrathyroidal thymic tissue in an adult patient: a case report and review of the literature.

BACKGROUND: Ectopic intrathyroidal thymic tissue is a rare diagnosis, specifically in adults. Such ectopic tissue is usually misdiagnosed as benign or malignant thyroid lesions and is mainly investigated by ultrasonography and pathologic examination. CASE PRESENTATION: We present the case of an adult 31-year-old Persian female patient with a cervical mass and no other significant medical history. The lesion had hypo- to isoechoic features on sonographic imaging, and needle aspiration examination revealed lymphoid cells suspicious of lymphoid malignancies. However, pathologic examination after resection of the lesion showed normal thymic tissue. CONCLUSIONS: The rare entity of ectopic thymic tissue within the thyroid gland in adult patients requires meticulous examination by clinicians, radiologists, and pathologists to diagnose the condition with high accuracy and plan appropriate management.

Machine learning approach to differentiation of peripheral schwannomas and neurofibromas: A multi-center study.

BACKGROUND: Non-invasive differentiation between schwannomas and neurofibromas is important for appropriate management, preoperative counseling, and surgical planning, but has proven difficult using conventional imaging. The objective of this study was to develop and evaluate machine learning approaches for differentiating peripheral schwannomas from neurofibromas. METHODS: We assembled a cohort of schwannomas and neurofibromas from 3 independent institutions and extracted high-dimensional radiomic features from gadolinium-enhanced, T1-weighted MRI using the PyRadiomics package on Quantitative Imaging Feature Pipeline. Age, sex, neurogenetic syndrome, spontaneous pain, and motor deficit were recorded. We evaluated the performance of 6 radiomics-based classifier models with and without clinical features and compared model performance against human expert evaluators. RESULTS: One hundred and seven schwannomas and 59 neurofibromas were included. The primary models included both clinical and imaging data. The accuracy of the human evaluators (0.765) did not significantly exceed the no-information rate (NIR), whereas the Support Vector Machine (0.929), Logistic Regression (0.929), and Random Forest (0.905) classifiers exceeded the NIR. Using the method of DeLong, the AUCs for the Logistic Regression (AUC = 0.923) and K Nearest Neighbor (AUC = 0.923) classifiers were significantly greater than the human evaluators (AUC = 0.766; p = 0.041). CONCLUSIONS: The radiomics-based classifiers developed here proved to be more accurate and had a higher AUC on the ROC curve than expert human evaluators. This demonstrates that radiomics using routine MRI sequences and clinical features can aid in differentiation of peripheral schwannomas and neurofibromas.

Variable Expressivity of Wolfram Syndrome in a Family with Multiple Affected Subjects.

PURPOSE: To study the genetic basis and clinical manifestations of Wolfram syndrome in a multi-affected family. METHODS: Complete clinical examinations including urological, ophthalmic, neurological, and endocrinologic assessment were performed for three affected family members. Genomic DNA was extracted from peripheral blood leukocytes with salting out method and all WFS1 exons and their flanking regions were sequenced. Candidate variation was screened for segregation in the pedigree by Sanger sequencing. RESULTS: A known pathogenic missense mutation in WFS1 gene (c.1885C > T which leads to p.Arg629Trp in the encoded protein) was identified in all affected individuals. Both clinical and genetic investigations confirmed Wolfram syndrome diagnosis with variable phenotypic features. CONCLUSION: Identical mutations in the Wolfram syndrome causative gene can lead to variable manifestations of the syndrome even in the same family. Although the medical findings and clinical examination are imperative for the diagnosis of Wolfram syndrome, genetic testing is useful to confirm the diagnosis, especially in cases with possible reduced penetrance of the characteristic signs.

Association between iron deposition in splenic,hepatic and myocardial tissues assessed by T2* relaxometry technique.

BACKGROUND: Decreasing signal intensity of the spleen assessed by T2* MRI is a frequent finding in patients with beta-thalassemia due to iron deposition within the reticuloendothelial cells in this organ. This parameter can also be applied to determine the candidates for blood cell transfusion. However, the association between splenic siderosis and iron overload in other vital organs such as heart and liver remains unclear. The present study aimed to assess the correlation between iron deposition in splenic, hepatic and myocardial tissues by T2* relaxometry technique. METHODS: This cross-sectional study included 39 consecutive patients with a definitive diagnosis of beta-thalassemia major who underwent spleen, liver and heart MRI examinations for iron deposition and cardiac function. RESULTS: No significant correlation was found between the heart and splenic T2* relaxation time (R=0.206, P=0.357). We revealed a strong correlation between the splenic T2* relaxation time and hepatic calculated T2*s (R=0.515, P=0.014). The liver T2* values can be predicted from the splenic T2*s by a new linear equation. According to the ROC curve analysis, the splenic T2* could significantly, but moderately predict moderate to severe from mild liver iron excess (AUC=0.667). CONCLUSION: Our study demonstrated a significant linear correlation between the splenic and hepatic T2* relaxation time, probably indicative of the same iron deposition mechanism, and made us available to write a linear model that would predict the deposited iron density in the spleen with the use of the magnetic resonance T2* values.

Machine Assist for Pediatric Posterior Fossa Tumor Diagnosis: A Multinational Study.

BACKGROUND: Clinicians and machine classifiers reliably diagnose pilocytic astrocytoma (PA) on magnetic resonance imaging (MRI) but less accurately distinguish medulloblastoma (MB) from ependymoma (EP). One strategy is to first rule out the most identifiable diagnosis. OBJECTIVE: To hypothesize a sequential machine-learning classifier could improve diagnostic performance by mimicking a clinician's strategy of excluding PA before distinguishing MB from EP. METHODS: We extracted 1800 total Image Biomarker Standardization Initiative (IBSI)-based features from T2- and gadolinium-enhanced T1-weighted images in a multinational cohort of 274 MB, 156 PA, and 97 EP. We designed a 2-step sequential classifier - first ruling out PA, and next distinguishing MB from EP. For each step, we selected the best performing model from 6-candidate classifier using a reduced feature set, and measured performance on a holdout test set with the microaveraged F1 score. RESULTS: Optimal diagnostic performance was achieved using 2 decision steps, each with its own distinct imaging features and classifier method. A 3-way logistic regression classifier first distinguished PA from non-PA, with T2 uniformity and T1 contrast as the most relevant IBSI features (F1 score 0.8809). A 2-way neural net classifier next distinguished MB from EP, with T2 sphericity and T1 flatness as most relevant (F1 score 0.9189). The combined, sequential classifier was with F1 score 0.9179. CONCLUSION: An MRI-based sequential machine-learning classifiers offer high-performance prediction of pediatric posterior fossa tumors across a large, multinational cohort. Optimization of this model with demographic, clinical, imaging, and molecular predictors could provide significant advantages for family counseling and surgical planning.

Deep COVID DeteCT: an international experience on COVID-19 lung detection and prognosis using chest CT.

The Coronavirus disease 2019 (COVID-19) presents open questions in how we clinically diagnose and assess disease course. Recently, chest computed tomography (CT) has shown utility for COVID-19 diagnosis. In this study, we developed Deep COVID DeteCT (DCD), a deep learning convolutional neural network (CNN) that uses the entire chest CT volume to automatically predict COVID-19 (COVID+) from non-COVID-19 (COVID-) pneumonia and normal controls. We discuss training strategies and differences in performance across 13 international institutions and 8 countries. The inclusion of non-China sites in training significantly improved classification performance with area under the curve (AUCs) and accuracies above 0.8 on most test sites. Furthermore, using available follow-up scans, we investigate methods to track patient disease course and predict prognosis.

Assessing the abilities of senior otolaryngology residents and graduated otolaryngologists in recognizing skull base elements in axial CT scan: proposing a new method for differentiating superior orbital fissure and optic canal.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the ability of recognizing some important elements of the skull base in axial CT-scan cuts, including the optic canal (OC), superior orbital fissure (SOF), vidian canal (VC), foramen rotundum (FR), jugular foramen (JF) and hypoglossal canal (HC). METHODS: In this study, 25 otolaryngology residents and 25 recently graduated otolaryngologists were evaluated in terms of their recognition of skull base elements, using 30 axial CT-scan cuts. Two months later, the exam related to skull base CT scans was taken in groups after a brief anatomy courses for otolaryngology residents. RESULTS: The percentage of correct answers from otolaryngology residents regarding OC, SOF, VC, FR, JF, and HC in the first exam were 74 ± 26, 47 ± 34, 65 ± 30, 41 ± 38, 58 ± 26, and 68 ± 32, respectively. The correct answer for each element was similar between groups, and the differences were not statistically significant (p > 0.05). p value for the differences observed regarding the percentage of correct answers for the second exam between trained otolaryngology residents and recent otolaryngology graduates regarding OC and JF was no significant (p > 0.05) but significant for the other elements with better result in trained otolaryngology residents and most for SOF (p > 0.0001). CONCLUSION: This study showed that the ability of recognition for the mentioned elements in axial CT-scan cuts was low among otolaryngology residents and graduated otolaryngologists. The proposed novel method for distinguishing SOF from OC had a powerful and long-lasting effect on trainee.

Metformin synergistically increases the anticancer effects of lapatinib through induction of apoptosis and modulation of Akt/AMPK pathway in SK-BR3 breast cancer cell line.

Objectives: Combination chemotherapy is a beneficial intervention for breast cancer, versus single therapy. We investigated the effect of Metformin (Met) on Lapatinib (Lap)-induced apoptosis in SK-BR3 cells. Materials and Methods: Toxic effect of Met and Lap on SK-BR3 cells was measured using MTT assay. Flow cytometry was used to measure the co-treatment effect of Met on lapatinib-induced apoptosis. The relative expression of Bax, Bcl2, and P21 was measured using a real-time PCR. The activity of caspase 3 and 9 was measured using an ELISA kit. The protein level of AMPK and Akt was determined using Western blot analysis. Results: Metformin and lapatinib alone and combined form showed significant time- and dose-dependent toxic effects on SK-BR3 cell viability. The greatest synergistic inhibitory effect on the cell viability [combination index (CI) = 0.51] was remarkable at Met 100 mM combined with Lap 100 nM. The combination has a stronger apoptotic death (46%) versus lapatinib alone. The combination considerably increased the mRNA expression of Bax and P21, and caspase 3 and 9 activity, while, decreasing the mRNA expression of Bcl2. Additionally, the combination significantly up-regulated and down-regulated the protein levels of AMPK and Akt, respectively. Conclusion: The metformin-lapatinib combination can induce more potent apoptotic death versus each compound individually. The combination may be suggested as a valuable therapeutic intervention in patients with breast cancer. However, additional in vivo studies are necessary to evaluate the clinical use of the combination for induction of apoptosis and its antitumor effects.

The Effect of Sexual Counseling Using BETTER Model on Sexual Function of Women with Infertility: A Randomized Controlled Trial.

Objective: Infertility can have adverse effects on sexuality of women. This study aims to examine the effect of sexual counseling based on the BETTER Model on the sexual function of Iranian women with infertility. Method: Eighty women with infertility were randomly assigned to either intervention or control groups. Female Sexual Function Index and Enrich Marital Satisfaction Scale were completed by participants at baseline and two months after. Results: All domains of FSFI (except for pain) were significantly increased (p < 0.001) after the intervention. Conclusions: Results showed that two sessions of sexual counseling can be used to improve the sexual health of infertile women.

A Multicenter Survey on the Trend of Chest CT Scan Utilization: Tracing the First Footsteps of COVID-19 in Iran.

BACKGROUND: Chest computed tomography (CT) scan has been used widely to diagnose COVID-19 in Iran. OBJECTIVES: To trace the footsteps of COVID-19 in Iran by exploring the trend in using chest CT scans and its economic impact on radiology departments. Methods: In this cross-sectional study, the number of imaging examinations from 33 tertiary radiology departments in 9 large cities of Iran was collected from September 23, 2019 to March 20, 2020 (Months 1 to 6) and the corresponding months in 2018-2019. RESULTS: A 50.2% increase was noted in the chest CT scan utilization in 2019-2020 compared to 2018-2019. This increase was +15%, +15%, +27%, +2%, +1% in Months 1-5 of 2019-2020, respectively. In Month 6 of 2019-2020, a 251% increase in the acquisition of chest CT scans was observed compared to the Month 6 of 2018-2019. Following negative balance of revenue from Month 1 to 5 with respect to the inflation rate, the total income in Month 6 was further 1.5% less than the same Month in 2018-19. CONCLUSION: The observed peak in chest CT utilization in Month 3 prior to the surge in Month 6 could be explained by the seasonal influenza. However, unawareness about an emerging viral disease, i.e. COVID-19, might have underutilized chest CT in Months 4 and 5 before the official announcement in Month 6. The unbalanced increase in the workload of radiology departments in the shortage of cardiothoracic radiologists with the simultaneous decrease in income initiated a vicious cycle that worsened the economic repercussions of the pandemic.

Perfusion Computed Tomography Scan Imaging in Differentiation of Benign from Malignant Parotid Lesions

Abstract Introduction The most common site of salivary gland tumors is the parotid gland. Computed tomography (CT), magnetic resonance imaging (MRI), and sonography are imaging modalities to differentiate benign from malignant parotid tumors. Objective The aim of this study is the evaluation of the diagnostic value of perfusion CT for differentiating histological categorization of benign and malignant parotid tumors. Methods A total of 29 patients with parotid neoplasms were enrolled in this study. Mean age and all CT perfusion variables (gradient and permeability, blood flow[BF], blood volume [BV], mean transit time [MTT], permeability surface [PS], maximum intensity projection [MIP], time-density curve [TDC], and time to peak [TTP]) were compared among three groups (malignant tumors [MTs],Warthin's tumor [WT] and pleomorphic adenomas [PA]). Results The mean age of the patients was 55.9±14.1 (26-77), and 15 of them were male (51.7%). Eleven lesions were PAs [37.9%], 8 lesions were WTs (27.6%0 and 10 lesions (34.5%) were MTs (6 acinic cell carcinomas [ACCs], 3 adenocystic carcinomas [AdCCs], and 1 mucoepidermoid carcinoma [MEC]). The mean age of the patients with WTs was 62±7.5 years; 52±14.2 for patients with Pas, and 55.2±17.2 for those with MTs (p=0.32). The mean MIP was 122.7±12.2 in WT, while it was 80.5±19.5 in PA, and 76.2±27.1 in MTs (p<0.001); The mean MIP for WT was higher than for PAs and MTs; the values of MTs and PAs were not statistically different. The average of BF, BV, and curve peak were higher inWTs in comparison with the other two groups, and curve time 2 and TTP were higher in PAs in comparison with MTs. Conclusion Based on this study, perfusion CT of the parotid gland and its parameters can distinguish between benign and malignant parotid masses.

The analgesic effect of metformin on paclitaxel-induced neuropathic pain model in rats: By considering pathological results.

BACKGROUND AND OBJECTIVE: Metformin (MET) has been used as an antidiabetic agent for type II diabetes. At the same time, recent researches have shown that the clinical improvement of MET is useful for nerve damage. In this study, we investigated the analgesic effect of MET in paclitaxel (PAC)-induced neuropathic pain. MATERIALS AND METHODS: Forty-two adult, female rats, Wistar strain weighing 220 ± 10 g were randomly divided into 5 experimental groups. PAC was intraperitoneally (IP) administered (2.0 mg/kg) for 4 groups every other day (0, 2, 4, and 6 days). By the 30th day, MET (100, 200, and 400 mg/kg) was administered to 4 groups. Before and after treatment, basal pain threshold values were measured with Randall-Selitto analgesiometer test. At the end of experiment, pathological values were measured in selected regions including brain (motor cortex, M1), spinal cord (L4-L5), sciatic nerve, and muscle. RESULTS: According to our results, PAC-induced neuropathic pain reached to highest level at 14th day. Four hundred milligram/kilogram concentration of MET remarkably decreased PAC-induced neuropathic pain. On the other hand, pathologic features have shown that PAC had significant pathological change in the brain and spinal cord while in the peripheral nerves and muscles had not shown any pathological change. CONCLUSION: The pathological results of the current study for the first time demonstrated that MET beside of its antidiabetic effects reversed neuropathic pain induced by PAC. Consequently, this research can be promising for cancer patients that suffering from neuropathic pain induced by anticancer drugs.

Perfusion Computed Tomography Scan Imaging in Differentiation of Benign from Malignant Parotid Lesions.

Introduction The most common site of salivary gland tumors is the parotid gland. Computed tomography (CT), magnetic resonance imaging (MRI), and sonography are imaging modalities to differentiate benign from malignant parotid tumors. Objective The aim of this study is the evaluation of the diagnostic value of perfusion CT for differentiating histological categorization of benign and malignant parotid tumors. Methods A total of 29 patients with parotid neoplasms were enrolled in this study. Mean age and all CT perfusion variables (gradient and permeability, blood flow [BF], blood volume [BV], mean transit time [MTT], permeability surface [PS], maximum intensity projection [MIP], time-density curve [TDC], and time to peak [TTP]) were compared among three groups (malignant tumors [MTs], Warthin's tumor [WT] and pleomorphic adenomas [PA]). Results The mean age of the patients was 55.9 ± 14.1 (26-77), and 15 of them were male (51.7%). Eleven lesions were PAs [37.9%], 8 lesions were WTs (27.6%0 and 10 lesions (34.5%) were MTs (6 acinic cell carcinomas [ACCs], 3 adenocystic carcinomas [AdCCs], and 1 mucoepidermoid carcinoma [MEC]). The mean age of the patients with WTs was 62 ± 7.5 years; 52 ± 14.2 for patients with Pas, and 55.2 ± 17.2 for those with MTs ( p = 0.32). The mean MIP was 122.7 ± 12.2 in WT, while it was 80.5 ± 19.5 in PA, and 76.2 ± 27.1 in MTs ( p < 0.001); The mean MIP for WT was higher than for PAs and MTs; the values of MTs and PAs were not statistically different. The average of BF, BV, and curve peak were higher in WTs in comparison with the other two groups, and curve time 2 and TTP were higher in PAs in comparison with MTs. Conclusion Based on this study, perfusion CT of the parotid gland and its parameters can distinguish between benign and malignant parotid masses.