جستجوی مقالات مرتبط با کلیدواژه « MRI » در نشریات گروه « پزشکی »

Radiomic feature reproducibility assessment is critical in radiomics‑based image biomarker discovery. This study aims to evaluate the impact of preprocessing parameters on the reproducibility of magnetic resonance image (MRI) radiomic features extracted from gross tumor volume (GTV) and high‑risk clinical tumor volume (HR‑CTV) in cervical cancer (CC) patients.

This study included 99 patients with pathologically confirmed cervical cancer who underwent an MRI prior to receiving brachytherapy. The GTV and HR‑CTV were delineated on T2‑weighted MRI and inputted into 3D Slicer for radiomic analysis. Before feature extraction, all images were preprocessed to a combination of several parameters of Laplacian of Gaussian (1 and 2), resampling (0.5 and 1), and bin width (5, 10, 25, and 50). The reproducibility of radiomic features was analyzed using the intra‑class correlation coefficient (ICC).

Almost all shapes and first‑order features had ICC values > 0.95. Most second‑order texture features were not reproducible (ICC < 0.95) in GTV and HR‑CTV. Furthermore, 20% of all neighboring gray‑tone difference matrix texture features had ICC > 0.90 in both GTV and HR‑CTV.

The results presented here showed that MRI radiomic features are vulnerable to changes in preprocessing, and this issue must be understood and applied before any clinical decision‑making. Features with ICC > 0.90 were considered the most reproducible features. Shape and first‑order radiomic features were the most reproducible features in both GTV and HR‑CTV. Our results also showed that GTV and HR‑CTV radiomic features had similar changes against preprocessing sets.

Primary idiopathic frozen shoulder (FS) causes pain and stiffness in the shoulder joint. Over time, this disease causes restriction of shoulder motion. We undertook this study to evaluate possible correlation of MRI findings with outcome of conservative management in FS. A total of 65 cases participated in prospective cohort study. The correlation of MRI findings obtained before commencing the treatment with outcome of non-operative management (Mean of ROM, VAS, SST and OSS) was evaluated. Anterior extracapsular edema significantly correlated with FF, EXR, VAS (a) and OSS. The effusion in humeral side of axillary recess significantly correlated with ROM restriction in ABD, EXR. Capsular thickness of glenoid portion showed good significance with FF, ABD, VAS (a) and OSS. Increased thickness of CHL showed negative correlation with improvement of EXR (P=0.049) (r=-0.617). Thickening of IGHL showed negative correlation with improvement of ABD (p=0.005 r=-0.862) and FF (p=0.007 r=-0.831). Mean Height of Axillary recess (HAR) was 7.2mm (3.5-11mm). HAR showed negative correlation with VAS pain scale (P=0.036) (r=-0.682) and OSS (P=0.038) (r=-0.668) Thickness of the joint capsule and effusion at the axillary fold are important factors for refractory frozen shoulder. We can recommend MRI for refractive cases and low threshold of expectation can be set for conservative management in patients with above findings. Level of evidence: III

Hearing loss is the most common sensory-neurological defect in humans. The most common hearing impairment is sensorineural hearing loss (SNHL) caused by the inner ear and related nerves. Diffusion tensor imaging (DTI) is an advanced MRI technique that can provide valuable information about auditory neural pathways and their microstructural changes. The present study was designed to investigate the microstructural changes in auditory pathways-related fiber tracts in children with SNHL. 

Twenty-two children including 11 subjects with SNHL aged 1-4 years and 11 healthy children were examined as controls. Then, DTI-derived parameters, such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD), and radial diffusivity (RD), and volume of fiber tracts were extracted from the inferior longitudinal fasciculus, acoustic radiation, and uncinate fasciculus. 

The results showed an increase in MD, RD, and AxD as well as a decrease in FA, volume, and diameter of auditory-pathway-related fiber tracts. Interestingly, there was an increase in the FA of acoustic radiation.

White matter connections in the auditory canal decrease and AR integrity increases due to compensatory effects. These probably reflect atrophy or degradation as well as compensatory cross-modal reorganization in the absence of auditory input and the use of sign language.

Health examinations are performed every six months. X-rays, magnetic resonance imaging (MRI), ECGs, and blood tests are all part of health examinations. In this investigation, the silent T2 Fast-Spin-Echo (FSE) and Gradient-Recalled Echo (GRE) MRI head examination sequences are compared. Noise is produced during an MRI test in addition to images.
This research was conducted by adjusting the parameters on the MRI, such as time repeat (TR), time echo (TE), and echo train length (ETL). Then, the resulting silent sequence image is simulated with a simulation program.
The variation of TR 440 with TE 24 in the GRE sequence for the white matter (WM) tissue has the highest signal to noise ratio (SNR) value. The cerebispinal fluid (CSF) tissue is also in the TR 560/TE 20 variant at the same time. Then, variations of TR 3360, TE 97, and ETL 33.6 have the highest peak signal to noise ratio (PSNR) measurement results in the WM or CSF tissue.
According to the study's findings, the average sound intensity level and mean square error (MSE) value produced by the GRE sequence protocol are less than those produced by the T2 FSE sequence protocol. While this is the case, the GRE sequence protocol generates an average PSNR value that is higher than the FSE T2 sequence protocol. The T2 FSE sequence with variations of TR 3360, TE 97, and ETL 33.6 may then be observed to be the best with the ideal noise level and SNR value.

This research aims to find an alternative oral contrast agents that can be used in magnetic resonance imaging (MRI) of the gastrointestinal (GI) tract, this contrast agent must be with no or minimum side effects and gives a best imaging quality.
We have used manganese supplement (intake daily dose) after dissolving in different amounts of distilled water to obtain samples (the concentrations of the manganese solution) as oral contrast agents. The samples have been placed in tubes and imaged by MRI for finding the sample that has lowest concentration with best imaging sequences and contrast of the images. After that, this sample was tested by healthy volunteers. The subjects of the investigation were ten healthy volunteers who were scanned pre-contrast and post-contrast. The image result is measured by the signal value to calculate the SNR, contrast and then a different test is performed. There were significant variations in stomach SNR values between pre and post contrast (p-value ).
The results show that the manganese supplement gives a good imaging sequences and contrast of the images. The contrast of manganese solution is positive on T1-weighted and negative on T2-weighted.This manganese supplement behavior is similar to the complex chemical manganese compounds studied in other investigations.
The manganese supplement can be considered as a positive contrast agent on T1-weighted and negative contrast agent on T2-weighted.

PNS (Peripheral nervous system) disease comprises a wide range of manifestations from acruable damage to nerve body degeneration. Finding proper imaging sequences of MRI (Magnetic Resonance Imaging) to maximize the detection sensitivity and specificity of PNS injuries, is the purpose for which this study was conducted. In this regard, due to Wallerian degeneration, axonal degeneration and inflammation after nerve injury, were mentioned as the inseparable factors of nerve damage, and clues to be detected by the MRI. Gadofluorine M and USPIO nanoparticles are candidates which provide contrast in multiple aspects, such as diagnostic approaches and drug tracking. For instance, the P904 USPIO particle is proper for long-term monitoring, while the CS015 (PAA-coated USPIO), USPIO-PEG-tLyP-1, and USPIO nanovesicles are appropriate for drug delivery. Besides contrast agents, the implication of gradient echo or 3D DW-PSIF provides more precious data over conventional sequences, including T2-weighed on the physiological or pathological PNS status. Eventually, although the real-time imaging and simplified procedure of the ultrasound technique have advantages over MRI, the low-resolution disvalues its benefits. Alternatively, there is a growing trend in the application of Diffusion-weighted imaging (DWI) to acquire a clear concept of disease diagnosis, along with Diffusion tensor imaging (DTI) to successfully monitor the rate of nerve regeneration that is applicable for therapeutic approaches.

 Endometriosis is one of the most common diseases in the female population. The range of diagnostic delays in this disease is long and leads to adverse health-related consequences. The aim of this study was to evaluate diagnostic experiences in patients with endometriosis who are candidates for laparoscopic surgery.

 This cross-sectional study was performed on 433 patients with endometriosis who were candidates for laparoscopic surgery referred to Shohada-Tajrish Hospital in Tehran, Iran, between January 2016 and December 2021. A questionnaire including demographic and clinical information, MRI, and pathology reports were collected from participants. The MRI lesions were segmented and the results were compared with pathology and clinical examination. For statistical analysis SPSS software, version 22 was used.

 A total of 433 participated in this study with a mean age of 34.18±7.99. The average estimated duration of disease symptoms (months) was 40.58±42.33. The predictive value of clinical symptoms is weak compared to MRI. However, the probability that the disease is not present when the clinical signs are negative is acceptable in most of the endometriosis sites. MRI considerably shows the true negative rate, but its sensitivity is only relatively acceptable for the diagnosis of ascites (67.66%). Calculating the accuracy of MRI reports probably shows the overall classification of the patients via MRI test.

despite extensive research, there are no suitable and accurate non-invasive methods for diagnosing endometriosis. MRI and clinical examination alone are not useful for definitive diagnosis and it is better to examine biomarkers and artificial intelligence for non-invasive and accurate diagnosis of this disease.

Intracranial chondroma and chondrosarcoma are very rare tumors that mainly originate from the base of the skull. Advanced neuroimaging studies, including magnetic resonance spectroscopy (MRS), play a pivotal role in both tumor diagnosis and presurgical planning.

We present two cases of intracranial cartilaginous tumors, including a chondroma and a chondrosarcoma, both of which presented with severe headaches. Due to inconclusive conventional MRI and MRS results, they were both primarily diagnosed as intra-axial brain tumors. However, pathological reports later confirmed the diagnosis of a chondroma and a chondrosarcoma.

Based on the present findings, the use of advanced neuroimaging techniques, such as MRS, may improve diagnostic accuracy. We believe that MRS can play a significant role in the surgical planning of similar cases. Also, reporting rare cases worldwide can contribute to the improvement of radiographic diagnosis.

 There is limited available evidence regarding the relationship between the COVID-19 pandemic and the use of medical technology in Iran.

 This study aimed to evaluate the effect of the COVID-19 pandemic on the usage of MRI and CTS in the west of Iran.

 This quasi-experimental study was conducted on collected data regarding the usage of MRI and CTS for 58 months from the health information systems of public hospitals in Kermanshah province (36 months before and 22 months after the pandemic). An interrupted time series analysis with segmented regression was used to assess the effect of the pandemic on the use of MRI and CTS. The population data were also obtained from the Statistics Centre of Iran (SCI).

 After the COVID-19 pandemic, there was a significant increase (67.1%) in the use of CTS, while MRI decreased by 50.8%. In the first month of the pandemic, there was a reduction (14%) in using CTS and a significant decrease (81%) in using MRI compared to the pre-COVID-19 baseline level. However, after the initial reduction, there were significant increases in the use of CTS (20.4 per 100,000 population) and MRI (0.21 per 100,000 population) every month during the COVID-19 pandemic.

 Based on the results, there was an increase in the use of CT scans and a decrease in the use of MRI after the pandemic, consistent with previous studies in other countries. Further studies are required to analyze the factors affecting the use of healthcare services during crises to improve preparedness for future pandemics.

Accurate segmentation of brain tissue in magnetic resonance imaging (MRI) is an important step in the analysis of brain images. There are automated methods used to segmentation the brain and minimize the disadvantages of manual segmentation, including time consuming and misinterpretations. These procedures usually involve a combination of skull removal, bias field correction, and segmentation. Therefore, segmented tissue quality assessment segmentation of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) is required for the analysis of neuroimages.
This paper presents the performance evaluation of three automatic methods brain segmentation, fluid and white matter suppression [FSL, Freesurfer (FreeSurfer is an open source package for the analysis and visualization of structural, functional, and diffusion neuroimaging data from cross-sectional and longitudinal studies) and SPM12 (Statistical Parametric Mapping)]. Segmentation with SPM12 was performed on three tissue probability maps: i) threshold 0.5, ii) threshold 0.7 and iii) threshold 0.9. In order to compare and evaluate the automatic methods, the reference standard method, i.e., manual segmentation, was performed by three radiologists.
Comparison of GM, WM and CSF segmentation in MR images was performed using similarities between manual and automatic segmentation. The similarity between the segmented tissues was calculated using diagnostic criteria.
Several studies have examined the classification of GM, WM, and CSF using software packages. In these studies, different results have been obtained depending on the type of method and images used and the type of segmented tissues. In this study, the evaluation of the segmentation of these packages with reference standard method is performed. The results can help users in selecting an appropriate segmentation tool for neuroimages analysis.

Diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) present the ability to selectively protect functional regions and fiber tracts of the brain when brain tumors are treated with radiotherapy. This study aimed to assess whether the incorporation of fMRI and DTI data into the radiation treatment planning process of brain tumors could prevent the neurological parts of the brain from high doses of radiation. In this investigational theoretical study, the fMRI and DTI data were obtained from eight glioma patients. This patient-specific fMRI and DTI data were attained based on tumor location, the patient’s general conditions, and the importance of the functional and fiber tract areas. The functional regions, fiber tracts, anatomical organs at risk, and the tumor were contoured for radiation treatment planning. Finally, the radiation treatment planning with and without fMRI & DTI information was obtained and compared. The mean dose to the functional areas and the maximum doses were reduced by 25.36% and 18.57% on fMRI & DTI plans compared with the anatomical plans. In addition, 15.59% and 20.84% reductions were achieved in the mean and maximum doses of the fiber tracts, respectively.  This study demonstrated the feasibility of using fMRI and DTI data in radiation treatment planning to maximize radiation protection of the functional cortex and fiber tracts. The mean and maximum doses significantly decreased to neurologically relevant brain regions, resulting in reducing the neuro-cognitive complications and improving the patient’s quality of life.

The assessment of the individual magnetic resonance imaging (MRI) features provides vital clues about the diagnosis of neurological complications during the postpartum period assists in the determination of the common neurological complications, differentiates these neurological disorders on basis of the MRI features, and helps with the early treatment planning. This study aimed to describe various complications that occur during the postpartum period to describe the MRI features of these neurological complications and the differentiating features from each other.

The study was a retrospective hospital-based analysis study conducted in the Department of Radiodiagnosis and modern imaging, Maharana Bhopal government hospital and RNT Medical College Udaipur, Rajasthan, India, from October 2017 to September 2018 (All the patients presented during this time frame were included in the study). A total of 58 postpartum cases of neurological disorders who were referred to the department for radiological evaluation and who had positive MRI imaging findings were included in the study.

Most common neurological symptoms were seizures followed by headache and focal neurological deficit (FND). Moreover, the most typical neurological complication was cerebral vein thrombosis, followed by posterior reversible encephalopathy syndrome (PRES). Other common complications were intracranial hemorrhage, ischemic infarcts, infections, acute hypoxic-ischemic encephalopathy, and metabolic encephalopathy. Rare but important findings included postpartum hypernatremic encephalopathy with extra pontine myelinolysis and rhabdomyolysis and postpartum reversible cerebral vasoconstriction syndrome (PRCVS).

MRI, along with angiography and venography, is the modality of choice to evaluate postpartum neurological symptoms and plays a crucial role in the early diagnosis of neurological complications. Furthermore, MRI helps establish this diagnosis early to avoid further complications.

Primary abdominal ectopic pregnancy is a very rare condition that occurs when the gestational sac is implanted directly into the abdominal peritoneum. In many cases it is difficult to have an exact diagnosis before explorative and therapeutic laparotomy or laparoscopic surgery and most of them are diagnosed during surgery. It can be a life threatening condition with high morbidity due to misdiagnosis or mismanagement. Cases Report: A 36 -year-old Iranian woman was admitted to Mahdieh hospital emergency department of shahid Beheshti medical science university (Tehran, Iran) with vaginal spotting and abdominal right lower quadrant pain with a background history of 6 weeks’ amenorrhea and a significant beta-human chorionic gonadotropin of 26660 IU/L. Subsequent transvaginal sonography revealed paraovarian fluid and 20×23 hyperheteroechoic right adnexal mass with peripheral vascularity indicating probable ectopic pregnancy. Following that, she underwent diagnostic and therapeutic laparotomy. It showed 400 cc blood and 50 cc clot in vesicouterine pouch that were suctioned. There was no evidence of right adnexal ectopic pregnancy however a resemblance of trophoblastic tissue was located on the wall of uterovesical pouch on the omentum.

We conclude that emergency laparotomy or laparoscopic surgery should be done to prevent occurrence of uncontrollable bleeding. Also utilizing MRI can be beneficial for exact detection the site of ectopic pregnancy before surgery which can be useful for perioperative planning and management of this condition.

 This study aimed to systematically evaluate the correlation between cognitive function and brain imaging findings in patients with hepatic encephalopathy (HE).

 We searched PubMed, China National Knowledge Infrastructure, and Wanfang databases to obtain literature on cognitive function and the diagnosis of HE via brain imaging from the establishment of the databases to March 20, 2023. Two researchers independently screened the literature, extracted data, and evaluated the risk of bias in the included studies. RevMan v. 5.3 software was used in the meta-analysis.

 A total of 14 articles were included. The meta-analysis showed that digit symbol test (DST) scores and psychometric HE scores (PHES) were positively correlated with the imaging findings of the frontal lobe in patients with HE, with correlation coefficients of 0.49 (Z = 0.53; 95% confidence interval [CI]: 0.23 ~ 0.83) and 0.52 (Fisher’s Z: 0.58; 95% CI: 0.41 ~ 0.76), respectively. The number connection test-A reaction times were negatively correlated with the signal in the globus pallidus, with a correlation coefficient of -0.23 (Z = - 0.23; 95% CI: - 0.43~ - 0.03); DST scores were positively correlated with the signal in the globus pallidus, with a correlation coefficient of 0.45 (Z = 0.49; 95% CI: 0.29 ~ 0.69); and PHES were positively correlated with the mean peak of grey matter, with a correlation coefficient of 0.52 (Z = 0.57; 95% CI: 0.46 ~ 0.73).

 Imaging findings are related to the cognitive function of patients with HE. Therefore, they can be used to evaluate the cognitive function of these patients and promptly intervene in and prevent the progression of the disease.

Schwannoma’s are benign tumors that can affect all nerves even the peripheric nerve. In the present study, a 66 year old case (man) which had a mass upon his wrist with a diagnostic delay of two years has been studied. Diagnosis was based on imaging features (Ultrasonography and MRI) with Electromyography (EMG) which was assessed by histopathological examination.