جستجوی مقالات مرتبط با کلیدواژه "magnetic resonance imaging" در نشریات گروه "پزشکی"

We present a case with an intrathoracic caudate lobe in a 45-year-old woman who referred with a complaint of nonspecific chest pain. She denied previous history of trauma or surgery. Computed tomography (CT) pulmonary angiography showed a paravertebral, soft tissue mass which raised suspicion of a pleural tumor. In the coronal plane, the mass was protruding to the abdomen and had similar density with liver. Magnetic resonance imaging confirmed the diagnosis.

Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are arguably the most prominent and most widely used healthcare diagnostic modalities for a wide range of applications. There are certain specific applications for which a particular modality is specifically used or has been adopted over a period of time because of reasons like good diagnostic accuracy, fast diagnosis, etc. One such application for CT has been “Spinal Fracture Diagnosis” and for MRI has been “Brain Tumor Detection”. This study presents case studies from different time periods to demonstrate the evolution of these respective applications and emphasizes the role of Artificial Intelligence (AI) based techniques like machine learning, deep learning, etc. for advancements in the diagnostic process. The case studies will enable the new researchers to understand the background and the work done in the respective time period. The time period of the studies referred to is between the years 2000 and 2023 (Present date). The purpose of this study is to enlighten the reader about the evolution of spinal fractures and brain tumor diagnosis which are understood to be primary applications of CT and MRI, respectively and, encourage further study into topics pertaining to AI-based tools used in diagnostic modalities for applications like automatic detection and prediction, smart decision making, early detection, etc.

Pineal Gland (PG) is a midline brain structure and part of the epithalamus, a dorsal posterior segment of the diencephalon. Most findings on the role of this structure in brain function are relevant to melatonin secretion, and only a few reports are available on its involvement in brain cognition.

Due to some suggestions on the role of the diencephalon areas, including the PG, in the human memory system, we used data from two previous MRI studies on 32 and 295 healthy individuals, in order to identify first, if the PG shows activations in fMRI and during a memory retrieval task as well as showing functional connectivity with other brain structures, and second, if there are any associations between the PG volume and the memory scores of the individuals.

Using a standard PG atlas, our results showed significant activations in PG during memory retrieval, with the strength of these activations increasing with the increment of the cognitive load of the task. Also, PG showed functional connectivity with other brain structures during fMRI, the pattern of which also changed with the cognitive load of the retrieval. Finally, the volume of the PG showed significant associations with the scores of the memory tests.

Our knowledge of the PG still needs improvement, and we hope our findings here could be a help for that as well as a help to better understand the mechanisms of memory storage and retrieval in humans.

T1 thermometry is considered a straight method for the safety monitoring of patients with deep brain stimulation (DBS) electrodes against radiofrequency-induced heating during Magnetic Resonance Imaging (MRI), requiring different sequences and methods. This study aimed to compare two T1 thermometry methods and two low specific absorption rate (SAR) imaging sequences in terms of the output image quality. In this experimental study, a gel phantom was prepared, resembling the brain tissue properties with a copper wire inside. Two types of rapid gradient echo sequences, namely radiofrequency-spoiled and balanced steady-state free precession (bSSFP) sequences, were used. T1 thermometry was performed by either T1-weighted images with a high SAR sequence to increase heating around the wire or T1 mapping methods. The balanced steady-state free precession (bSSFP) sequence provided higher image quality in terms of spatial resolution (1×1×1.5 mm3 compared with 1×1×3 mm3) at a shorter acquisition time. The susceptibility artifact was also less pronounced for the bSSFP sequence compared with the radiofrequency-spoiled sequence. A temperature increase, of up to 8 ℃, was estimated using a high SAR sequence. The estimated change in temperature was reduced when using the T1 mapping method.  Heating induced during MRI of implanted electrodes could be estimated using high-resolution T1 maps obtained from inversion recovery bSSFP sequence. Such a method gives a direct estimation of heating during the imaging sequence, which is highly desirable for safe MRI of DBS patients.

Mammograms often reveal breast microcalcifications, necessitating invasive procedures to ascertain whether they are cancerous or benign.

Although many microcalcifications are linked to noncancerous conditions, this study sought to investigate the efficacy of a computer-aided detection (CAD) system using breast MRI in distinguishing between benign and malignant breast anomalies.

This cross-sectional study included forty patients with mammographically suspicious microcalcifications who underwent stereotactically-guided biopsies at our institution over two years. Prior to the biopsy, these patients received a breast MRI within eight weeks. Surgical interventions were carried out for cases identified as malignant or of uncertain malignant potential. The study aimed to determine diagnostic benchmarks by comparing the breast imaging reporting and database system (BI-RADS) category assignments from initial mammography screenings and breast MRI reports to the pathology findings.

Histopathology reports showed that of the total cases, 23 were benign, and 17 were malignant. Breast MRI exhibited a sensitivity of 88.8%, specificity of 54.5%, a positive predictive value of 58.5%, and a negative predictive value of 94.1%. Further analysis using CAD demonstrated sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 50.0%, 59.0%, and 100%, respectively.

Utilizing breast MRI with the support of CAD, radiologists could significantly enhance their capability to differentiate between benign and malignant mammographic microcalcifications. This innovative diagnostic approach has the potential to decrease the necessity for unnecessary breast biopsies.

Investigate the immediate resonance magnetic image changes undergone by the lumbar canal after indirect decompression and compare them at one-year post-intervention. We also investigate the clinical outcome of indirect decompression at one-year follow-up. Imaging changes in patients who underwent indirect lumbar decompression and percutaneous posterior fixation were analyzed with one-year follow-up. Radiographic measurements were performed preoperatively and postoperatively (at one year), and the area of lumbar canal occupation and yellow ligament by nuclear magnetic resonance was compared preoperatively, at 48 hours post-surgery, and at one year. Radiographic measurements included disc height, foraminal height, total lumbar lordosis, and segmental lordosis. The VAS lumbar and lower limb scales and the Oswestry Disability Index (ODI) were used to assess clinical outcomes. A total of 21 male and 23 female patients underwent indirect decompression at 64 lumbar levels. A significant improvement was observed in the clinical evaluation of all patients’ post-surgery (p < 0.001) in all radiographic parameters. There was an immediate increase in the lumbar canal at 48 hours (p < 0.001), which continued to increase at one year post-intervention (p < 0.05). The yellow ligament occupation area decreased at 48 hours (p < 0.001) and continued to decrease until one year (p < 0.01). Four complications were recorded, one of which was a posterior tract infection requiring open decompression. Indirect decompression for degenerative lumbar disease provided successful clinical outcomes, including indirect expansion of the dural sac at 48 hours post-procedure, with progressive increase in the lumbar canal area at one-year follow-up. Level of evidence: III

Soft tissue hemangiomas are among the most prevalent soft tissue tumors and can pose diagnostic challenges due to their propensity to extend into various regions. In our case, imaging studies facilitated effective characterization of the mass, and timely intervention with sclerotherapy enabled adequate initial control of the lesion.  Subsequently, medical management with propranolol and a second scheduled surgical intervention with sclerotherapy contributed to a reduction in the lesion size, alleviation of symptoms, and improvement in prognosis. 

Case Report:

We present a rare case of a giant cervical soft tissue hemangioma with laryngeal extension in an adult female, initially misdiagnosed as a primary laryngeal hemangioma. This case underscores the critical role of diagnostic imaging in assessing the extent of these vascular tumors. 

A thorough assessment of the suspected site, as well as the entire head, neck, and chest, should be conducted for all patients with suspected hemangiomas.

Cystic renal masses (CRM) are found incidentally in many patients undergoing lumbar MRI. cysts.

The present study aimed to determine the diagnostic value of T2-weighted imaging features of CRM on lumbar spine MRI and their reliability in differentiating complex renal lesions from simple

All lumbar MRIs performed between 2019 and 2021 were included in this prospective study. Patients with simple cysts on MRI underwent a renal ultrasound by an expert radiologist. Patients with complex or suspicious cysts, based on sonographic characteristics, were subjected to a CT scan with contrast. For complex cysts identified on MRI, patients underwent a CT scan with contrast without first undergoing an ultrasound examination. Finally, the sensitivity, specificity, and positive and negative predictive values of T2 lumbar MRI images were calculated to determine the nature of the cysts.

A total of 2,789 lumbar MRIs were performed during the study period. Of these, 169 cases (6.05%) were reported to have incidental kidney cysts. No significant differences were found between the age and sex of the patients. The size of the cysts differed significantly between complex and simple cysts. The sensitivity, specificity, and positive and negative predictive values of MRI in determining the nature of the cyst were calculated to be 100%, 98%, 83%, and 100%, respectively.

The results of the present study showed that further examinations using ultrasound and CT scans in patients with simple renal cysts on lumbar MRI are not recommended, which can significantly reduce health care costs.

The precise evaluation of tissue permeability using the Magnetic Resonance Imaging (MRI) method requires high-quality images. Due to noisy acquired dynamic MRI images, some methods of processing are required to obtain the imaging detail of interest.
This study aimed to implement Empirical Mode Decomposition (EMD) to the Lock-Locker (LL) images to improve the permeability of the normal tissue and tumor region, evaluated by the Quantitative Autoradiography (QAR) method.
In this experimental and analytical study, the EMD method was used to improve the tissue permeability from the LL- MRI images of the rat brain. The EMD components were extracted from LL images, and the resulting components were combined using different weighting factors. The tissue permeability was derived by extracting the information of each pixel from the LL image series and fitting curves to the data.
The optimum weighted combination factors images were 0.7 for the middle and low-frequency components and 1 for the high-frequency component. The calculated tissue permeability was between 0.0023-0.0043 (ml.min-1.g-1) for abnormal tissue. 
The estimation of the permeability of tumors in the rat brain with the LL images and the processed LL images by the EMD method shows that the EMD method and the weighted combination of frequency components can improve the permeability calculation in the LL images for the rat brain. The results of permeability estimation by EMD due to noise reduction of LL images are closer to the values obtained from the Quantitative Autoradiography (QAR).

The application of nanotechnology in the molecular diagnosis and treatment of cancer is essential. This study aimed to investigate the influence of curcumin-coated ultra-small superparamagnetic iron oxide (USPIO) as a T1 contrast agent in Magnetic Resonance Imaging (MRI). . In this experimental study, the influence of curcumin-coated USPIO (Fe3O4@C) on the diagnosis of the cancer cell line was investigated. After synthesis, characterization, and relaxation of Fe3O4@C, the contrast changes in T1-weight MRI to mouse colon carcinoma 26 cell line were evaluated in vitro. Fe3O4@C nanoparticles (NPs) are good at imaging; based on a relaxometry test, the r1 and r2 relaxivities of Dotarem were 3.139 and 0.603 mM−1s−1, respectively. Additionally, the r1 and r2 relaxivities of Fe3O4@C were 3.792 and 1.3 mM−1s−1, respectively, with the rate of 2.155 of r2/r1 NPs.  The NPs can be identified as a positive contrast agent with a weight of T1 in MRI. The coresh-ell Fe3O4@C NPs can be effective in cancer treatment and diagnosis because of the therapeutic effects of curcumin and the properties of USPIO.

Macroscopic tumor implants in the hernia sac are a very rare condition. They occur as a result of the implantation of malignant cells in the malignant ascites from the inguinal canal to the hernia sac. In this case report, we share the clinical and radiological findings of the macroscopic tumoral implants in the hernia sac at the level of the inguinal canal and scrotum in a male patient aged 65 years with a history of total gastrectomy for gastric adenocarcinoma and developing malignant ascites six months after the surgery.

Detection of axillary metastases in breast cancer is critical for treatment options and prognosis. The aim of this study is to investigate the value of radiomic features obtained from short tau inversion recovery (STIR) sequences in magnetic resonance imaging (MRI) of primary tumor in breast cancer in predicting axillary lymph node metastasis (ALNM).

Lesions of 165 patients with a mean age of 51.12 ±11 (range 28-82) with newly diagnosed invasive breast cancer who underwent breast MRI before treatment were manually segmented from STIR sequences in the 3D Slicer program in all sections. Machine learning (ML) analysis was performed using the extracted 851 features Python 3.11, Pycaret library program. Datasets were randomly divided into train (123, 80%) and independent test (63, 20%) datasets. The performances of ML algorithms were compared with area under curve (AUC), accuracy, recall, presicion and F1 scores.

Accuracy and AUC in the training set were in the range of 57 %-86 % and 0.50-0.95, respectively. The best model in the training set was the catBoost classifier with an AUC of 0.95 and 84% accuracy. The AUC, accuracy, recall, precision values and F1 score of the CatBoost classifier on the test set were 0.92, 84 %, 89 %, 85 %, 86 %, respectively.

Radiomic features obtained from primary tumors on STIR sequences have the potential to predict ALNM in invasive breast cancer.

Man in a barrel syndrome (MIBS) presents with bilateral upper extremity weakness but preserved strength in face, neck, and lower extremities. In this case report, two cases of MIBS were admitted to the emergency department (ED) presented. The first patient injured his neck after falling off a ladder. The second patient was a victim of a traffic accident. Bilateral upper extremity weakness was examined in the first patient at first admission to the ED. On the other hand, progressive weakness was shown in the second patient during ED follow-up. The cervical imaging findings consisted with MIBS. This case report and review of literature highlights that physicians should consider every possible cause, even the rarest ones when a patient complains of neck trauma with non-specific symptoms. Rapid identification and treatment of treatable causes such as cerebral hypoperfusion are vital for patient prognosis.

Apparent diffusion coefficient (ADC) statistics can be valuable in distinguishing three types of brain tumors. The aim is to evaluate the capability of volume under the receiver operating characteristic (ROC) surface (VUS) for concurrent differential diagnosis of glioblastoma (GBM), lymphoma (LYM), and metastatic tumor(s) (MTTs) lesions of brain malignancies.

Investigated Magnetic Resonance Imaging (MRI) included 57 GBM, 25 LYM, and 25 MTT that were pathological diagnoses, after MR imaging. Region of interest (ROI) was taken from tumor regions (TUMOR), enhancement area (ENHANCED), and peritumoral edema (EDEM) regions. ADC maps were obtained after selecting a region of interest, and First-Order Histogram Features (FOHs) were extracted. Statistical analysis was performed by MedCalc version 15.8 for comparison of continuous variables between three groups of lesions and plotting the ROC curves. For VUS and correct classification rates (CCR) calculations the R software v2.13.1 with the DiagTest3grp package was used. The confidence interval level was 95% for significant results. Diagnostic accuracy of ADC in the differentiation of mentioned three groups was performed using ROC surface.

ADCMin, ADC75 and ADC95 Percentile values in TUMOR groups of ROI, ADCMaximum, ADCMin, ADCMean, ADCMedian , ADCUniformity and ADCEntropy  in ENHANCED  and ADC25, ADC75, ADC95 Percentiles, ADCMean , ADCNormal Mean , ADCMedian, ADCEntropy, ADCThird Moment and ADCStandardDeviation in EDEM had significant VUS values results among GBM, LYM and MTTs .

VUS analysis is a helpful statistical method for categorizing types of brain tumors. Using the application of FOHs and proposed cut-off points for them by the VUS analysis, the differentiation of more than two types of brain tumors would be possible, concurrently. This will help neurologists and neurosurgeons to plan their treatment and surgery or monitor the status of patients’ therapeutic needs.

To date, magnetic resonance imaging (MRI) plays a critical role in the management of rectal cancer. Although neoadjuvant chemoradiotherapy (nCRT) is a gold standard approach in advance to surgical management, it might alter the tissue texture, affecting MRI findings applied for decision-making in a procedural approach.

The current study aimed to assess the predictive parameters in MRI associated with response to nCRT in rectal cancer.

The current cross-sectional study has been conducted on 50 patients with rectal cancer who were candidates for nCRT during 2020- 21. Data including tumor markers and MRI parameters including tumor signal, tumor stage (TMN), lymph node involvement, mesorectal fascia (MRF), extramural venous invation (EMVI), peritoneal reflection invasion and tumor size were gathered at baseline and within 4-6 weeks after nCRT. The predictive factors for response to nCRT were evaluated using tumor regression grade (TRG) and TNM staging.

Tumor size (P<0.001), MRI signal intensity (P=0.038), tumor appearance in diffuse weighted imaging (DWI) (P<0.001), tumor stage (P<0.001), lymph node involvement (P<0.001), MRF (P<0.001), EMVI (P<0.001), and peritoneal reflection invasion (P<0.001) remarkably improved in post-nCRT assessments. Tumor size was associated with 3.75 (95%CI: 1.61-8.72) and 2.64 (95%CI: 1.40-4.97) folds, and lymph node involvement was associated with 77% (95%CI: 0.21-15.02) and 60% (95%CI: 0.21- 11.96) increased probability of response to treatment based on TRG and TNM, respectively.

Based on the findings of this study, nCRT could remarkably improve adenocarcinoma of rectal cancer-related laboratory and imaging parameters; however, tumor size and lymph node involvement were the only predicting factors for response to nCRT.

 Incidental findings in imaging are defined as findings that appear accidentally in radiological images, and usually, the patient does not have a complaint related to the desired finding. These findings range from no-risk to high-risk. This study aimed to evaluate the prevalence of incidental findings of gynecological diseases in hip and sacroiliac Magnetic Resonance Imaging (MRI) in Imam Hossein Hospital in 2022.

 In this cross-sectional descriptive study, all patients referred to Imam Hossein Hospital (Iran-Tehran) during one year (2022) who underwent hip and sacroiliac MRI were evaluated. Hip and sacroiliac MRI images were reviewed. The following pathological findings were recorded: pelvic vascular congestion, ovarian cyst, myoma, and ovarian masses. Patients' information about age and underlying disease were also extracted from patients' files. Hip and sacroiliac diseases were also recorded. Finally, all recorded data were analyzed using the SPSS program.

 Hip and sacroiliac MRI of 364 female patients were assessed. The mean age of the patients was 50.18±13.46 years. Discopathy was the most prevalent finding in the MRI (41.76%) as a pathological finding. The prevalence of incidental findings was 32.3%. The most common incidental finding in MRI was free fluid with a prevalence of 12.1%, and ovarian cyst was seen in 6.3% of patients. There was a significant relationship between most of the incidental findings and age (P-values<0.05).

 The prevalence of incidental findings of gynecological diseases in women undergoing hip and sacroiliac MRI is considerable and shows the importance of the radiologist’s attention to review and report the entire MRI images.

 Considering the importance of paranasal sinus anatomy in treatment planning and related surgeries, the present study aimed to investigate the changes in the dimensions of paranasal sinuses according to age and gender by magnetic resonance imaging (MRI).

 MRI images of 310 patients, including 200 women and 110 men aged between 10 and 70 years old, were included in the study. The depths of all paranasal sinuses and the width of the left and right frontal sinuses were estimated in the axial plane. In addition, the height of the left and right frontal sinuses in the sagittal plane as well as the width and height of the maxillary and sphenoid sinuses in the coronal plane underwent measurement. All statistical analyses were performed using SPSS 21, and the significance level was considered at 0.05.

 Except for the width of the right maxillary sinus, the height of the left frontal sinus, and the width and depth of the left sphenoid sinus, a significant relationship was observed between the other dimensions of paranasal sinuses and gender (P<0.05). Only 5 dimensions, including the width of the left and right maxillary sinuses, the height of the left maxillary sinus, the depth of the left frontal sinus, and the depth of the right sphenoid sinus, had significant relationships with age, so that they decreased with age (P<0.05). The highest symmetry was between the left and right maxillary sinuses.

 The paranasal sinus was different in men and women. Some dimensions of paranasal sinuses had a significant relationship with age. These results can be used in planning prosthetic treatments and performing surgeries with fewer complications.

Beta thalassemia major (β-TM) is an inherited blood disorder. Affected patients require frequent blood transfusions, leading to iron deposition and end organ damage, particularly myocardial dysfunction. A 12-lead ECG is a readily available tool that could be used to screen for conduction abnormalities and arrhythmias as a marker of worsening myocardial function.  A total of 108 β-TM patients were evaluated for correlation between abnormal findings on the surface ECG and severity of myocardial iron deposition in magnetic resonance imaging as measured by T2* levels.  Patients with T2* below 20 msec had significantly longer PR intervals, P wave durations, and QTc intervals. Patients with T2* below 10 msec had the longest QRS duration and QRS activation times. Atrial fibrillation was more prevalent in patients with lower T2* levels. With a decrease in T2*, the probability of notching of QRS in the limb and precordial leads increased.  Abnormal ECG is prevalent in β-TM patients, and the frequency of changes increases with the severity of iron overload. A 12-lead ECG is a valuable and readily available tool for the early assessment of myocardial damage and the implementation of a timely and appropriate management strategy.