Papers by Afshin Mohammadi
Japanese Journal of Radiology
Purpose CT imaging has been a detrimental tool in the diagnosis of COVID-19, but it has not been ... more Purpose CT imaging has been a detrimental tool in the diagnosis of COVID-19, but it has not been studied thoroughly in pediatric patients and its role in diagnosing COVID-19. Methods 27 pediatric patients with COVID-19 pneumonia were included. CT examination and molecular assay tests were performed from all participants. A standard checklist was utilized to extract information, and two radiologists separately reviewed the CT images. Results The mean age of patients was 4.7 ± 4.16 (mean ± SD) years. Seventeen patients were female, and ten were male. The most common imaging finding was ground-glass opacities followed by consolidations. Seven patients had a single area of involvement, five patients had multiple areas of involvement, and four patients had diffuse involvement. The sensitivity of CT imaging in diagnosing infections was 66.67%. Also, some uncommon imaging findings were seen, such as a tree-inbud and lung collapse. Conclusion CT imaging shows less involvement in pediatric compared to adult patients, due to pediatric patients having a milder form of the disease. CT imaging also has a lower sensitivity in detecting abnormal lungs compared to adult patients. The most common imaging findings are ground-glass opacities and consolidations, but other non-common imaging findings also exist.
Antioxidants
Selenium (Se) deficiency has been implicated in the pathogenesis of Hashimoto’s thyroiditis (HT),... more Selenium (Se) deficiency has been implicated in the pathogenesis of Hashimoto’s thyroiditis (HT), although the available evidence is limited. The present study aimed to explore the interrelationships between serum Se status with measures of thyroid function and antioxidant defense in new cases of HT patients with hypoechogenic thyroid. HT patients (n = 49) and matched controls (n = 50) were recruited. Selenium, thyroid hormone panel, thyroid volume (TVol), glutathione (GSH), glutathione peroxidase3 (GPx3) activity, urinary iodine concentration (UIC), and urinary creatinine (Cr) were assessed. HT patients exhibited lower Se levels compared to controls (p < 0.001) with the rates of Se-deficient (<0.85 µmol/L) participants being 58.8% and 34%, respectively. Se-deficient patients exhibited higher thyroid stimulating hormone (TSH), Thyroid volume (TVol), thyroglobulin, antibody-titers, GPx3 activity and UIC/Cr compared to Se-sufficient patients (all p < 0.001). In the Se-deficie...
European Radiology
Objectives CT findings of COVID-19 look similar to other atypical and viral (non-COVID-19) pneumo... more Objectives CT findings of COVID-19 look similar to other atypical and viral (non-COVID-19) pneumonia diseases. This study proposes a clinical computer-aided diagnosis (CAD) system using CT features to automatically discriminate COVID-19 from non-COVID-19 pneumonia patients. Methods Overall, 612 patients (306 COVID-19 and 306 non-COVID-19 pneumonia) were recruited. Twenty radiological features were extracted from CT images to evaluate the pattern, location, and distribution of lesions of patients in both groups. All significant CT features were fed in five classifiers namely decision tree, K-nearest neighbor, naïve Bayes, support vector machine, and ensemble to evaluate the best performing CAD system in classifying COVID-19 and non-COVID-19 cases. Results Location and distribution pattern of involvement, number of the lesion, ground-glass opacity (GGO) and crazy-paving, consolidation, reticular, bronchial wall thickening, nodule, air bronchogram, cavity, pleural effusion, pleural thickening, and lymphadenopathy are the significant features to classify COVID-19 from non-COVID-19 groups. Our proposed CAD system obtained the sensitivity, specificity, and accuracy of 0.965, 93.54%, 90.32%, and 91.94%, respectively, using ensemble (COVIDiag) classifier. Conclusions This study proposed a COVIDiag model obtained promising results using CT radiological routine features. It can be considered an adjunct tool by the radiologists during the current COVID-19 pandemic to make an accurate diagnosis. Key Points • Location and distribution of involvement, number of lesions, GGO and crazy-paving, consolidation, reticular, bronchial wall thickening, nodule, air bronchogram, cavity, pleural effusion, pleural thickening, and lymphadenopathy are the significant features between COVID-19 from non-COVID-19 groups. • The proposed CAD system, COVIDiag, could diagnose COVID-19 pneumonia cases with an AUC of 0.965 (sensitivity = 93.54%; specificity = 90.32%; and accuracy = 91.94%). • The AUC, sensitivity, specificity, and accuracy obtained by radiologist diagnosis are 0.879, 87.10%, 88.71%, and 87.90%, respectively.
Polish Journal of Radiology
Purpose: Only five percent of thyroid nodules are malignant. It is important to find reliable and... more Purpose: Only five percent of thyroid nodules are malignant. It is important to find reliable and at the same time non-invasive methods to identify high-risk nodules. The aim of this study was to determine the diagnostic validity of a morphologic feature-oriented approach of ultrasound study for the identification of malignant thyroid nodules. Material and methods: Seventy-one thyroid nodules in 71 consecutive patients were evaluated with both ultrasonography (US) and US-assisted fine needle aspiration biopsy (FNAB). Thyroid grey-scale and power Doppler US were performed, and a Windows-based software was designed to process power Doppler US (PDUS) images that were recorded directly by the US device. We provided a histogram graph of coloured pixels and calculated the Malignancy Index to identify the probability of malignancy for each thyroid nodule. Results: Thirty-six nodules (50.7%) were determined to be malignant in FNAB. Area under the receiver operating curve was 0.91 (95% CI: 0.85-0.98) for PDUS-based malignancy index in differentiating malignant thyroid nodules from benign ones. The best cutoff point for malignancy index was determined to be 0.092, with a sensitivity of 86.1% and specificity of 80% in identifying malignant nodules. Conclusions: This PDUS-driven malignancy index using a contour-finding algorithm approach could accurately and reliably differentiate malignant and benign thyroid nodules. As a pre-FNAB assessment, the malignancy index may be able to reduce the number of patients with nodular thyroid disease undergoing this invasive procedure.
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, Jan 31, 2018
Speckle noise is the main factor that degrades ultrasound image contrast and segmentation failure... more Speckle noise is the main factor that degrades ultrasound image contrast and segmentation failure. Determining an effective filter can reduce speckle noise and improve segmentation performances. The aim of this study was to define a useful filter to improve the segmentation outcome. Twelve filters, including median, hybrid median (Hmed), Fourier Butterworth, Fourier ideal, wavelet (Wlet), homomorphic Fourier Butterworth, homomorphic Fourier ideal, homomorphic wavelet (Hmp_Wlet), frost, anisotropic diffusion, probabilistic patch-based (PPB), and homogeneous area filters, were used to find the best filter(s) to prepare thyroid nodule segmentation. A receiver operating characteristic (ROC) analysis was used for filter evaluation in the nodule segmentation process. Accordingly, 10 morphologic parameters were measured from segmented regions to find the best parameters that predict the segmentation performance. The best segmentation performance was reached by using 4 hybrid filters that m...
International Journal of Cancer Management
Iranian Journal of Radiology, 2009
To compare the diagnostic findings of ultrasonography and radiography in nasal fractures. Design ... more To compare the diagnostic findings of ultrasonography and radiography in nasal fractures. Design and Main Outcome Measures: In this prospective study, 63 patients (23 female and 40 male; mean age, 26.8 years) with clinical signs of a nasal bone fracture were investigated. All patients underwent radiography (lateral view of the nose plus occipitomental view) and ultrasonography (10-MHz ultrasound scanner) of the nasal dorsum and the lateral nasal walls and a clinical examination by 2 consultants. Thirty-six patients underwent nasal fracture reduction. Two radiographs and 3 ultrasound images of each patient were analyzed by 2 experienced readers at different times. After assessing the nasal dorsum and lateral nasal walls in radiographs and ultrasound images, they decided whether the nose was fractured or not or whether the results were uncertain. The results were analyzed by various statistical testing methods (for sensitivity, specificity, positive and negative predictive value, and accuracy). Results: Assessment of the lateral nasal walls revealed that ultrasonography was statistically superior (P=.04) to radiography. In contrast, assessment of the nasal dorsum showed radiography to be statistically superior (P=.01) to ultrasonography. Assessment of the nasal pyramid revealed no statistical difference between radiography and ultrasonography (P =.91). Conclusion: In assessment of the nasal pyramid, ultrasonography can be considered an alternative to radiography, with equivalent diagnostic performance.
Medical Ultrasonography, Dec 1, 2011
The aim of the study is to estimate the diagnostic sensitivity and utility of high-resolution ult... more The aim of the study is to estimate the diagnostic sensitivity and utility of high-resolution ultrasonography (HRUS) in comparison with a gold standard technique in the diagnosis of the nasal fracture. Using a retrospective study design, facial Computed Tomography (CT) and HRUS examinations were performed on 87 consecutive patients with nasal trauma. Ultrasonograms were obtained with a high frequency linear transducer (10 MHz). All patients also underwent facial conventional radiography (CR). The sensitivity and specificity for diagnosis of nasal fracture was evaluated for HRUS, CT and CR in comparison with the clinical examination. Then sensitivity and specificity of HRUS and CR were evaluated in comparison with CT. The sensitivity and specificity of HRUS, CT and CR in comparison with clinical exam in the diagnosis of nasal bone fracture was 97% and 100%, 86% and 87%, 72% and 73% respectively. The sensitivity and specificity of HRUS and CR in detecting fracture line in comparison with CT was 100% respectively 91%, and 79% respectively 95%. HRUS is a reliable and available method for diagnosis of nasal bone fractures especially in the fracture, which is confined to the nasal bone and can be used as a modality of choice for investigation of nasal fracture.
International Journal of Clinical and Experimental Medicine, 2012
IntroductionRecently, minimally invasive parathyroidectomy (MIP) has been developed and is gainin... more IntroductionRecently, minimally invasive parathyroidectomy (MIP) has been developed and is gaining popularity among surgeons. For this reason, preoperative localization is playing an important role to detect the precise location of the affected gland and to increase the success rate.Material and methodsFrom June 2007 to June 2011, 56 consecutive patients (11 men and 45 women) with primary or secondary hyperparathyroidism in our center underwent Gray scale, color Doppler and 99m-Tc MIBI scan prior to operative management of parathyroid lesions.ResultsThe sensitivity, specificity and accuracy of US and MIBI scan for pHPT was 88%, 94%, 91% and 70%, 100% and 85% respectively. In patients with sHPT, the sensitivity, specificity and accuracy of US and MIBI scan was 54%, 93%, 76% and 25%, 100% and 72.9% respectively. The overall sensitivity of combined US and MIBI scan in pHPT and sHPT was 97% and 45% respectively. The overall sensitivity, specificity and accuracy of CDUS in diagnosis of parathyroid lesions in pHPT and sHPT is 97%, 100%, 98.6% and 62%, 100% and 83% respectively.ConclusionThe overall sensitivity and specificity of US and MIBI in preoperative localization of parathyroid adenoma in sHPT is lower than pHPT and performing CDUS can increases the overall sensitivity and specificity of imaging methods in accurate localization of parathyroid lesion.
Introduction: There are multiple causes for ascites and conventional diagnostic method for most o... more Introduction: There are multiple causes for ascites and conventional diagnostic method for most of them is paracentesis. This method is invasive and time consuming. The aim of this study is to survey the reliability of measuring gallbladder wall thickness to discriminate between cirrhotic and malignant ascites. Materials and Methods: In our study we measured the gallbladder wall thickness by ultrasonography in 100 consecutive patients with portal hypertension induced ascites and in 100 consecutive patients with peritoneal carcinomatosis induced ascites. Results: The mean Gallbladder wall thickness was 3.94±0.69 mm in cirrhotic patients and 2.26±0.62 mm in patients with peritoneal carcinomatosis. Gallbladder wall thickening in cirrhotic patients was sig ni ficantly more compared to patients with peritoneal carcinomatosis (p-value=0.001). Conclusion: This study shows that the thickened gallbladder wall in patients with ascites is highly predictive for diagnosis of portal hypertension induced ascites.
Mædica, 2015
Wandering spleen is an unusual surgical condition that is generally asymptomatic, but the long an... more Wandering spleen is an unusual surgical condition that is generally asymptomatic, but the long and mobile vascular pedicle of the spleen predisposes it to torsion. Various imaging modalities can be used to diagnose a wandering spleen. We present the case of a 23 year-old female patient with abdominal pain, in whom torsion of the spleen was diagnosed preoperatively, using color Doppler sonography, as a whirlpool appearance.
Iranian Journal of Radiology
Dear Editor, Since foreign bodies (FB) retained after penetrating trauma may cause severe infecti... more Dear Editor, Since foreign bodies (FB) retained after penetrating trauma may cause severe infection or inflammatoryreaction,detection and removal is necessary.1 Radiolucent foreign bodies such as wood often re-main undiscovered;2 therefore, sonography plays an important role in the evaluation of these cases.3 Forty-seven patients were referred for ultrasono-graphic (US) examination because of the possible retention of non-opaque soft tissue foreign bodies in the lower or upper extremities during a three-year period (from January 2006 to January 2009). We detected and localized the foreign bodies in 45 of the 47 patients by ultrasonography. Then the sensitivity and specificityofsonographyinthediagnosisofsofttissueforeignbodieswasevaluatedas95.7% and 100%, respectively. Sonography revealed the foreign bodies as hyperechoic objects with or without posterior acoustic shadowing in all 45 patients (Figs. 1 & 2). Among 21 patients with wooden foreign bodies, posterior acoustic shadowing wa...
Iranian Journal of Radiology
We report the case of an 18-year-old man with a needle-like foreign body embedded in the liver. T... more We report the case of an 18-year-old man with a needle-like foreign body embedded in the liver. The foreign body was found in the RUQ on the plain abdominal x-ray obtained for further evaluation of a previous ingested foreign body. Computed tomography confirmed the diagnosis. The patient was asymptomatic but surgery was performed and the needle was removed. Surgery confirmed the diagnosis.
Iranian Journal of Radiology
Background/Objective: Patients in unstable clinical conditions with blunt abdominal trauma requir... more Background/Objective: Patients in unstable clinical conditions with blunt abdominal trauma require rapid evaluation of the abdominal organ injury to assess the need for laparatomy. This prospective study was conducted to determine the use of emergency sonography for evaluating patients with blunt abdominal trauma and to compare the accuracy of sonography with the results of diagnostic peritoneal lavage (DPL), exploratory laparatomy and CT scan. Patients and Methods: Emergency sonography was performed prior to any of the diagnostic methods, peritoneal lavage, exploratory laparatomy and CT, on 204 patients with blunt abdominal trauma. Sonography was performed with the “focused abdominal sonography for trauma” (FAST) technique and six areas of the abdomen were examined to detect free peritoneal fluid. Results: Sonography showed a sensitivity of 95.4%, specificity of 78.4% and an overall accuracy of 89% in the diagnosis of free peritoneal fluid. The positive and negative predictive valu...
Iranian journal of kidney diseases, 2015
Arteriovenous fistula (AVF) is the best permanent access for hemodialysis. Swelling and pain due ... more Arteriovenous fistula (AVF) is the best permanent access for hemodialysis. Swelling and pain due to thrombosis and infection is common at fistula site. Angiosarcoma is one of rare but important differential diagnosis of these signs. We present a patient on CAPD with angiosarcoma at AVF.
International journal of clinical and experimental medicine, 2014
Preoperative accurate localization of enlarged adenoma (s) in primary hyperparathyroidism (PHPT) ... more Preoperative accurate localization of enlarged adenoma (s) in primary hyperparathyroidism (PHPT) is a vital necessity. Technetium 99m sestamibi scanning is commonly used with reported acceptable sensitivities; however, false negative scan studies remain a problem. Determining effective factors on the sensitivity of the scan might improve the diagnostic value of the study by selecting the correct candidates. Patients with PHPT indicated for parathyroidectomy from June 2008 to June 2013 who had positive ultrasonographic findings for single adenoma were included in the study. All patients underwent 99m-Tc MIBI scintigraphy before the surgery. Postoperative histopathology results were used as gold standard. The effect of patients' age, gender, preoperative serum PTH level, volume of the gland and having cystic components in the adenoma on the results of the scan were investigated. A total of 70 patients (mean age: 47.76 ± 11.80; 87.1% (n = 61), female) were included. Mean PTH level ...
Medical ultrasonography, 2014
Pulmonary fibrosis is the main cause of mortality in patients with Systemic Scleroderma (SSc). Th... more Pulmonary fibrosis is the main cause of mortality in patients with Systemic Scleroderma (SSc). This study was performed to investigate the utility of modified trans-thoracic ultrasound (TTUS) scoring system according to the comet tail sign (B-line artifacts) and to compare it with high-resolution computed tomography (HRCT) findings in patients with SSc and pulmonary involvement. Seventy subjects with SSc diagnosed according to the American College of Rheumatology criteria were enrolled. All subjects underwent HRCT followed by TTUS for comet tail sign detection in order to predict the degree of lung fibrosis. The modified TTUS assessment was performed at 10 intercostals spaces level. A significantly positive correlation between TTUS and the severity of pulmonary involvement (Spearman's correlation coefficient= 0.695, P < 0.001), (LR=74.36, P<0.001) was found. When compared with HRCT as the gold standard method, the sensitivity, specificity, positive and negative predictive ...
International journal of clinical and experimental medicine, 2013
The large number of patients that require fine needle aspiration biopsy (FNAB) to discriminate ma... more The large number of patients that require fine needle aspiration biopsy (FNAB) to discriminate malignant from benign thyroid nodules is a practical problem especially in iodine deficient area. To obtain an ultrasound (US) score and for predicting malignant nodules and reduce the number of unnecessary and expensive FNAB. A total of 280 thyroid nodules observed from August 2009 to August 2011 that had underwent FNAB were evaluated by US for echogenicity, peripheral halo, microcalcifications and intranodular vascularity. showed that nodules with two ultrasonographic features (US score = 4) were characterized by a 67.9% sensitivity and a 87% specificity for prediction of malignant thyroid nodules. According to our data, we suggest FNAB for nodules with US score ≥ 4. The practical use of this US score may help reduce unnecessary and expensive FNAB especially in iodine-deficient areas.
International journal of clinical and experimental medicine, 2013
Alveolointerstitial involvement is a common manifestation in patients with connective tissue diso... more Alveolointerstitial involvement is a common manifestation in patients with connective tissue disorders. The aim of our study is to investigate the utility of modified TTUS scoring system compared with HRCT findings of pulmonary involvement in rheumatoid lung disease. Thirty one consecutive patients with a suspected diagnosis of rheumatoid lung involvement were examined with high resolution transthoracic ultrasonography for detecting of ultrasonographic comet tail signe as a ultrasonographic marker of lung involvement in alveolointerstitial involvement in rheumatoid lung disease and the results of them were compared with High resolution computed tomography as gold standard method for diagnosis of lung involvement in this patients. In comparison with HRCT as gold standard method, the sensitivity, specificity, positive and negative predictive value of TTUS was 73.58%, 88.23%, 95.12% and 51.72% respectively. Modified TTUS can be a useful imaging modality in the evaluation of even early ...
Iranian journal of kidney diseases, 2013
Microalbuminuria is a reliable marker of diabetic nephropathy. Establishment of peripheral vascul... more Microalbuminuria is a reliable marker of diabetic nephropathy. Establishment of peripheral vascular complications leads to early diagnosis, prevention, and treatment of renal and cardiovascular complications. This study investigated the value of ankle-brachial index (ABI) for prediction of microalbuminuria in type 2 diabetic patients. Measurement of ABI with color Doppler ultrasonography was carried out for 206 patients with type 2 diabetes mellitus. An ABI Index less than 0.9 was defined as a predictive marker for atherosclerosis. Microalbuminuria and risk factors of atherosclerosis were compared between the patients categorized based on the ABI values. The mean ABI was 1.1 ± 0.2 (range, 0.052 to 1.6), and 41 (20%) had an abnormal ABI (< 0.9). The correlations were significant between abnormal ABI and duration of disease (P = .04), cardiovascular event and cardiac care unit admission (P = .001), hypertension (P = .01), and dyslipidemia (P = .01). There was a significant correlat...
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Papers by Afshin Mohammadi