Accuracy Of MRI Research Articles

Correlation of Magnetic Resonance Imaging and Arthroscopy Findings in Cruciate Ligaments and Meniscus Injury of Knee in West Nepal

Introduction: Magnetic resonance imaging is a noninvasive diagnostic modality and provides clinically relevant information to orthopaedic surgeons by detecting and characterizing injuries of cruciate ligaments and meniscus of the knee. MRI is routinely used before arthroscopic examination and surgery. Arthroscopy is considered the reference standard for the diagnosis of injuries of cruciate ligaments and meniscus of the knee and hence the efficacy of MRI needs to be compared with arthroscopic findings. Methods: This was a retrospective observational study at Bheri hospital, Nepalgunj. A total of 114 Patients who were investigated with MRI and managed with arthroscopic procedures for a knee injury, between June 2017 to February 2022, were included in the study.Data analysis was done for determining true positive, true negative, false positive and false negative as per MRI and arthroscopic findings.Sensitivity, specificity, positive predictive value and negative predictive value were calculated based on specific equations. Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MRI for ACL were 89.65%, 96.42%, 96.29%, 90% & 92.98%, PCL was 96.42%, 100%, 100%, 97.72% & 99.12%, the medial meniscus was 88.46%, 88.70%, 86.79%, 90.10% & 88.59% and lateral meniscus was 84.61%, 94.31%, 81.48%, 95.40% & 92.10% respectively. Conclusions: MRI is an excellent noninvasive modality for imaging the knee and it yields high accuracy in diagnosing injuries of cruciate ligaments and meniscus.

Diagnostic accuracy of multiparametric MRI in endometrial cancer and its adjunctive value in identifying high-risk women requiring surgical staging

Dear Editor, Endometrial cancer is the most common gynaecological cancer in developed countries, with a five-year survival rate of 81%.1,2 Prognostic factors include the International Federation of Gynecology and Obstetrics (FIGO) stage, depth of myometrial invasion (MI), lymph node involvement, cervical stromal involvement, and histological grade. Total hysterectomy with bilateral salpingo-oophorectomy (THBSO), pelvic and para-aortic

Review of the role of MRI and 18 F-sodium fluoride PET/computed tomography in the characterisation of spinal bone metastases in a cohort of patients with breast cancer.

The purpose of the study was to compare the diagnostic accuracy and relative usefulness of MRI and 18 F-NaF (sodium fluoride) PET/computed tomography (CT) for detection of spinal bone metastases in a cohort of patients with high-risk breast cancer (BrCa). A retrospective study was conducted of patient and lesion-based analyses on 66 consecutive patients (median age, 62.5 years; age range, 33-91 years) who underwent Spinal MRI as well as 18 F-NaF PET-CT for restaging of newly diagnosed recurrent BrCa with no previous bone metastases. Both scans were performed within 20 days of each other. Review of prior images, clinical decisions, multi-disciplinary team discussions and decisions as well as follow-up information including scans and definitive tests was performed at least 12 months after the initial scans. Of the 66 patients reviewed, 26 patients had documented spinal bone metastases on one or both modalities, while 40 patients were considered bone disease free on both modalities and this was confirmed on follow-up. On lesion-based analysis, the findings of 18 F-NaF PET-CT and spinal MRI were concordant in 51 patients (77.3%). In the remaining patients, 18 F-NaF PET/CT detected more lesions in 4 patients (7.6%) and MRI detected more lesions in 10 patients (15.1%). Interestingly, there was a very high, 97 % concordance (64 patients) between spinal MRI and 18 F-NaF PET-CT when staging of spinal bone metastasis was taken into consideration. In one patient MRI identified two spinal bone metastases which were not seen on 18 F-NaF PET/CT; and, in one patient 18 F-NaF PET/CT showed few spinal bone metastases when no lesion was seen on MRI. Our study showed a high level of concordance between 18 F NaF PET-CT and spinal MRI within the setting of detection of bone lesions in the spine in a cohort of patients with high-risk BrCa. In our opinion, this high level of concordance negates the need to perform both tests although each test may be indicated for slightly different reasons. Further longitudinal studies across a longer duration and more centres may provide more definitive answers.

Denoising of diffusion MRI in the cervical spinal cord – effects of denoising strategy and acquisition on intra-cord contrast, signal modeling, and feature conspicuity

Quantitative diffusion MRI (dMRI) is a promising technique for evaluating the spinal cord in health and disease. However, low signal-to-noise ratio (SNR) can impede interpretation and quantification of these images. The purpose of this study is to evaluate several dMRI denoising approaches on their ability to improve the quality, reliability, and accuracy of quantitative diffusion MRI of the spinal cord. We evaluate three denoising approaches (Non-Local Means, Marchenko-Pastur PCA, and a newly proposed Patch2Self algorithm) and conduct five experiments to validate the denoising performance on clinical-quality and commonly-acquired dMRI acquisitions: 1) a phantom experiment to assess denoising error and bias; 2) a multi-vendor, multi-acquisition open experiment for both qualitative and quantitative evaluation of noise residuals; 3) a bootstrapping experiment to estimate uncertainty of parametric maps; 4) an assessment of spinal cord lesion conspicuity in a multiple sclerosis group; and 5) an evaluation of denoising for advanced parametric multi-compartment modeling. We find that all methods improve signal-to-noise ratio and conspicuity of MS lesions in individual diffusion weighted images (DWIs), but MPPCA and Patch2Self excel at improving the quality and intra-cord contrast of diffusion weighted images – removing signal fluctuations due to thermal noise while improving precision of estimation of diffusion parameters even with very few DWIs (i.e., 16-32) typical of clinical acquisitions. These denoising approaches hold promise for facilitating reliable diffusion observations and measurements in the spinal cord to investigate biological and pathological processes.

Presumed radiological diagnosis of solid pseudopapillary tumors: do we really know what we are watching?

ObjectivesLittle is known about the clinicians’ ability to ascertain the identity of a pancreatic lesion as solid pseudopapillary tumors (SPT)preoperatively. We led this retrospective study to figure out the disease spectrum that mimic SPT, the key features of SPT and the accuracy of CT and MRI in characterizing them. MethodsRadiological and clinical database at a tertiary pancreatic disease center (Peking Union Medical College Hospital) was searched for patients who received CT or MRI with a presumed radiological diagnosis of SPT. Those patients’ clinical information and final pathological diagnosis were collected. ResultsDuring 2018.10–2021.12, 200 patients had a presumed radiological diagnosis of SPT, and 132 of them had unambiguous pathological diagnosis. SPT were confirmed in only 63.6% (84/132), while the others had a variety of neoplastic and nonneoplastic lesions, including pancreatic neuroendocrine tumors (n = 15), pseudocysts (n = 4), mucinous cystic neoplasms (n = 4), serous cystadenomas (n = 3), neural sheath tumors (n = 3), lymphoepithelial cysts (n = 2), and several very rare pathologies (n = 17). Of note, 11.4% (15/132) of those were benign or nonneoplastic lesions, while 6.8% (9/132) were neoplasms with highly aggressive nature, or pancreatic metastases, which require systematic evaluation and staging instead of upfront surgery. Retrospective radiological analysis based on key imaging features, clinical history and laboratory findings had an improved diagnostic accuracy of 78.5% with CT and 77.8% with MRI. ConclusionsThere is a broad disease spectrum mimicking SPT at CT and MRI. Key imaging features, clinical information and laboratory findings must be integrated to improve the diagnostic accuracy.

Effect of magnetic resonance imaging pre-processing on the performance of model-based prostate tumor probability mapping

Objective. Multi-parametric magnetic resonance imaging (mpMRI) has become an important tool for the detection of prostate cancer in the past two decades. Despite the high sensitivity of MRI for tissue characterization, it often suffers from a lack of specificity. Several well-established pre-processing tools are publicly available for improving image quality and removing both intra- and inter-patient variability in order to increase the diagnostic accuracy of MRI. To date, most of these pre-processing tools have largely been assessed individually. In this study we present a systematic evaluation of a multi-step mpMRI pre-processing pipeline to automate tumor localization within the prostate using a previously trained model. Approach. The study was conducted on 31 treatment-naïve prostate cancer patients with a PI-RADS-v2 compliant mpMRI examination. Multiple methods were compared for each pre-processing step: (1) bias field correction, (2) normalization, and (3) deformable multi-modal registration. Optimal parameter values were estimated for each step on the basis of relevant individual metrics. Tumor localization was then carried out via a model-based approach that takes both mpMRI and prior clinical knowledge features as input. A sequential optimization approach was adopted for determining the optimal parameters and techniques in each step of the pipeline. Main results. The application of bias field correction alone increased the accuracy of tumor localization (area under the curve (AUC) = 0.77; p-value = 0.004) over unprocessed data (AUC = 0.74). Adding normalization to the pre-processing pipeline further improved diagnostic accuracy of the model to an AUC of 0.85 (p-value = 0.000 12). Multi-modal registration of apparent diffusion coefficient images to T2-weighted images improved the alignment of tumor locations in all but one patient, resulting in a slight decrease in accuracy (AUC = 0.84; p-value = 0.30). Significance. Overall, our findings suggest that the combined effect of multiple pre-processing steps with optimal values has the ability to improve the quantitative classification of prostate cancer using mpMRI. Clinical trials: NCT03378856 and NCT03367702.

Breast MRI: an illustration of benign findings.

Despite its unparalleled sensitivity for aggressive breast cancer, breast MRI continually excites criticism for a specificity that lags behind that of modern mammographic techniques. Radiologists reporting breast MRI need to recognise the range of benign appearances on breast MRI to avoid unnecessary biopsy. This review summarises the reported diagnostic accuracy of breast MRI with particular attention to the technique's specificity, provides a referenced reporting strategy and discusses factors that compromise diagnostic confidence. We then present a pictorial review of benign findings on breast MRI. Enhancing radiological skills to discriminate malignant from benign findings will minimise false positive biopsies, enabling optimal use of multiparametric breast MRI for the benefit of screening clients and breast cancer patients.

Real-time phase contrast MRI versus conventional phase contrast MRI at different spatial resolutions and velocity encodings

PurposesTo compare the accuracy of real-time phase-contrast echo-planar MRI (EPI-PC) and conventional cine phase-contrast MRI (Conv-PC) and to assess the influence of spatial resolutions (pixel size) and velocity encoding on flow measurements obtained with the two sequences. MethodsFlow quantification was assessed using a pulsatile flow phantom (diameter: 9.5 mm; mean flow rate: 1150 mm3/s; mean flow velocity: 1.6 cm/s). Firstly, the accuracy of the EPI-PC was checked by comparing it with the flow rate in the calibrated phantom and the pulsation index from Conv-PC. Secondly, flow data from the two sequences were compared quantitatively as a function of the pixel size and the velocity encoding. ResultsThe mean percentage difference between the EPI-PC flow rate and calibrated phantom flow rate was −2.9 ± 2.1% (Mean ± SD). The pulsatility indices for EPI-PC and Conv-PC were respectively 0.64 and 0.59. In order to keep the flow rate measurement error within 10%, the ROI in Conv-PC had to contain at least 13 pixels, while the ROI in EPI-PC had to contain at least 9 pixels. Furthermore, Conv-PC had a higher velocity-to-noise ratio and could use a higher velocity encoding than EPI-PC (20 cm/s and 15 cm/s, respectively). ConclusionsThe result of this in vitro study confirmed the accuracy of EPI-PC, and found that EPI-PC can adapt to lower spatial resolutions, but is more sensitive to velocity encoding than Conv-PC.

The comparison between contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging in diagnosing bladder urothelial carcinoma.

The surgical treatment of bladder urothelial carcinoma depends on whether the tumor has invaded the bladder muscular layer. Normal ultrasound and contrast-enhanced magnetic resonance imaging (contrast-enhanced MRI) are widely used in patients bear bladder tumors; the latter is also widely used in estimating the muscularis invasion of bladder cancer (BC). However, contrast-enhanced ultrasound (CEUS) is rarely used in this aspect. As the gold standard in diagnosing muscularis invasion remains being pathological examination, this study was set to find out whether there are differences between CEUS and contrast-enhanced MRI in diagnosing bladder malignant tumors and in diagnosing the muscularis invasion of the bladder urothelial carcinoma under the guide of the pathological results. 160 patients from Yongchuan Hospital of Chongqing Medical University and The Second Affiliated Hospital of Chongqing Medical University were recruited from July 1st, 2021, to June 30th, 2022. Patients are arranged to undergo CEUS, contrast-enhanced MRI and then take a surgery. After surgery, we compare the results of CEUS, MRI and the pathological results, using software to run the statistical examinations. The accuracies of CEUS and contrast-enhanced MRI in diagnosing malignant bladder tumors were 85.90 and 84.62%, and they had no differences (P > 0.05). While the accuracies of CEUS and contrast-enhanced MRI in diagnosing the muscularis invasion were 84.62 and 76.92%, in which CEUS had a better sensitivity (P < 0.05). We found that CEUS and contrast-enhanced MRI had no differences in diagnosing the different pathological types (benign or malignant) of BC, but CEUS holds a better sensitivity in diagnosing muscularis invasions of bladder urothelial carcinoma than the contrast-enhanced MRI.

Staging Breast Cancer with MRI, the T. A Key Role in the Neoadjuvant Setting.

Breast cancer (BC) is the most common cancer among women worldwide. Neoadjuvant chemotherapy (NACT) indications have expanded from inoperable locally advanced to early-stage breast cancer. Achieving a pathological complete response (pCR) has been proven to be an excellent prognostic marker leading to better disease-free survival (DFS) and overall survival (OS). Although diagnostic accuracy of MRI has been shown repeatedly to be superior to conventional methods in assessing the extent of breast disease there are still controversies regarding the indication of MRI in this setting. We intended to review the complex literature concerning the tumor size in staging, response and surgical planning in patients with early breast cancer receiving NACT, in order to clarify the role of MRI. Morphological and functional MRI techniques are making headway in the assessment of the tumor size in the staging, residual tumor assessment and prediction of response. Radiomics and radiogenomics MRI applications in the setting of the prediction of response to NACT in breast cancer are continuously increasing. Tailored therapy strategies allow considerations of treatment de-escalation in excellent responders and avoiding or at least postponing breast surgery in selected patients.

Placenta Accreta Spectrum (PAS) Disorder: Ultrasound versus Magnetic Resonance Imaging.

PAS is one of the most dangerous conditions associated with pregnancy and remains undiagnosed before delivery in from half to two-thirds of cases. Correct prenatal diagnosis is essential to reduce the burden of maternal and fetal morbidity. The purpose of our study is to evaluate the accuracy of US and MRI in the diagnosis of PAS. In this retrospective study, 104 patients with suspected placenta accreta were enrolled and had been investigated with US and MRI. They were divided into four groups: no PAS, accreta, increta, and percreta. Compared to MRI, US results were higher in the diagnosis and in the identification of PAS severity (85% US vs. 80% MRI). For both methods, in the case of posterior placenta, there is greater difficulty in identifying the presence/absence of the disease (67% in both methods) and the severity level (61% US vs. 55% MRI). US, properly implemented with the application of defined and standardized scores, can be superior to MRI and absolutely sufficient for the diagnosis of PAS, limiting the use of MRI to a few doubtful cases and to cases in which surgical planning is necessary.

Accuracy of non-contrast enhancement multiparametric MRI to diagnose liver tumor compared to conventional MRI sequences

Magnetic resonance imaging is widely used to create detailed images of the organs and tissues. In daily clinical practice of diagnosing liver cirrhosis, it is still a challenge to find the best clinical diagnosis for detection hepatic lesions like hemangioma or hepatoma. In this study, we tried to compare the accuracy of method non-contrast enhancement multiparametric MRI (mpMRI) with conventional liver MRI. A total of 120 patients with liver cirrhosis were enrolled and were divided into two groups, 60 patients with hepatic hemangioma (HH, group A) and 60 patients with hepatocellular carcinoma (HCC, group B). MRI was first used for different diagnosis hepatic lesions without any invasive procedure or surgical treatment. All acquired MRI images were divided into 2 parts: the first part was the non-contrast enhancement multiparametric MRI (mpMRI), and the second part named the conventional liver MRI, was covered all images including non-contrast enhancement and dynamic contrast material-enhanced. The MRI images were interpreted by two experience gastrointestinal radiologists (I and II). Before analysis, the clinical manifestations, laboratory data, tissue biopsy results were not known. Paired samples t-test was used to analyze the significant difference of two-tailed probability (P &lt; 0.05), and its Hemangioma and Hepatoma of receiver operating characteristic curve and area under the ROC curves values were evaluated. In the results, two-tailed probability of non-contrast enhancement mpMRI sequences and the conventional liver MRI in group A was found to be P = 0.109, while that in group B was found to be P = 0.115. After Wilcoxon sign-ranked test, the two-tailed probability reached 0.557 in group A, while that of group B reached 0.624; both showed not difference between the two groups. In conclusion, the non-contrast enhancement mpMRI that included the half-Fourier single-shot turbo spin-echo (HASTE) with fat suppression T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) and susceptibility-weighted imagining (SWI) sequence can provide reliable information for effectively differentiate HH and HCC without using contrast materials. This study is expected to provide a reference for the application of MRI in clinical diagnose for a better enhanced method.

Comparison of Diagnostic Accuracy of Magnetic Resonance Imaging and Transient Elastography Fibro Scan for Detecting Liver Fibrosis

Objective: Diagnosing liver fibrosis without resorting to invasive surgery is in high demand but underserved. The focus of this study is on the diagnostic accuracy of MRI and the transient elastography fibro scan for liver fibrosis. Methodology: After the ethical approval from institute review board, sixty patients with liver fibrosis were selected by random sampling technique underwent multiparametric MR, transesophageal echocardiography (TE), and blood testing in this single-center cross-sectional study. Noninvasive treatment alternatives were weighed against histological information including stage and grade (such as MR fat and iron content). The diagnostic accuracy of each method for F3 and F4 hepatic fibrosis, as well as for advanced fibrosis, was evaluated using ROC curve analysis. Each technique was evaluated based on its accuracy (F3–F4). Results: Magnetic resonance elastography was used to find significant correlations between fibrosis stage and collagen content (r = 0.66; P = 0.001), as well as between inflammatory grade and collagen content (r = 0.53; P = 0.036). The MRE, TE, DCE-MRI, DWI, and APRI all had AUCs of 0.78 or above, while the AUC for identifying advanced fibrosis was 0.71. Advanced fibrosis AUC values were between 0.94 and 0.77, 0.79 and 0.79, and 0.70 and 0.70. (F3–F4). Practical implication: This study will to determine which diagnostic technique is better suited to accurately diagnose the liver fibrosis patients. Conclusion: The strongest correlation was seen between histological markers and MRI. The ability of magnetic resonance imaging to detect advanced liver fibrosis and cirrhosis was also superior to that of transient elastography fibro scans. Keywords: MRI, Liver fibrosis, diagnostic accuracy, transient elastography fibro scan

Comparison of multislice spiral CT and MRI in diagnosis of occult fracture of knee joint with meniscus and ligament injury

To investigate the diagnostic value of multislice spiral CT (MSCT) and MRI in occult fracture of knee joint with meniscus and ligament injury. From January 2020 to March 2021, 63 patients with knee occult fracture with meniscus and ligament injury, including 41 males and 22 females, aged from 21 to 67 years old, with an average of (44.35±8.77) years old, the course of disease ranged from 1 to 6 days, with an average of (4.64±1.75) days, the body mass index (BMI) was (19.85±2.78) kg/m2. MSCT and MRI data of 63 patients were collected and statistically analyzed to evaluage their diagnist value. The detection of MRI for occult knee fravtures with meniscus and ligament injury, joint cavity effusion, bone marrow edema, and articular surface injury were 100.00% (63/63), 95.24% (60/63), 42.86% (27/63) and 36.51% (23/63), respectively. The detection rates of MSCT were 49.21% (31/63), 41.27% (26/63), 0.00% (0/63) and 1.59% (1/63), respectively, significantly lwver than that of MRI (P<0.05). The diagnostic sensitivity, specificity and accuracy of MRI were significantly higher than those of MSCT(P<0.05). The sensitivity, specificity and accuracy of magnetic resonance imaging in the diagnosis of occult fracture of knee joint with meniscus and ligament injury are significantly better than that of MSCT. MRI has higher accuracy in the diagnosis of peripheral tissue diseases such as joint cavity, articular surface and bone marrow, and can reduce the risk of clinical misdiagnosis.

The Accuracy of Multiparametric MRI in Identification of Intraprostatic Tumor Deposits after Local Prostate Radiation Therapy

<h3>Purpose/Objective(s)</h3> To determine the accuracy of multiparametric (mp) MRI in identification of intraprostatic tumor deposits in prostate cancer patients previously treated with local radiation therapy (RT) using a systematic and targeted MR-guided transperineal prostate biopsy technique as a reference to guide and improve clinical workflow processes. <h3>Materials/Methods</h3> Twenty-three patients with localized prostate cancer who had been previously treated with external beam RT, brachytherapy, or combined external beam RT and brachytherapy, underwent a combined systematic and targeted MRI-guided prostate biopsy using a transperineal approach under general anesthesia. For each patient, a pre-biopsy mpMRI scan was obtained and imported into a prostate biopsy planning system. Transverse T2-weighted images were then reoriented from the supine to dorsal lithotomy position. Dividing the prostate into an apical and base section, a systematic array of transperineal biopsies spaced approximately 10mm apart was planned with additional biopsies targeting any mpMRI-identified PI-RADS 3, 4, or 5 lesions. Biopsy procedures were carried out in the dorsal lithotomy position using a transrectal ultrasound with stepper-stabilizer and template grid. Matching of the planning mpMRI images to live ultrasound images was achieved using the template grid as a reference. <h3>Results</h3> All patients successfully underwent their biopsy procedure as planned. The median PSA prior to biopsy was 5.5 ng/mL (range 2.1-24.6). The median number of biopsy specimens obtained per patient was 21 (range 13-34). Overall, the positive predictive value (PPV) of any PI-RADS 3-5 lesion (based on pathologic confirmation) was 81% (21/26). The individual PPV of PI-RADS 3, 4 and 5 lesions were 25% (1/4), 89% (16/18), and 100% (4/4), respectively. Forty-eight percent (11/23) of patients harbored mpMRI-unidentified prostate cancer. Thirty-five percent (8/23) of patients harbored mpMRI-unidentified GS≥7 disease. <h3>Conclusion</h3> Using prostate mpMRI to identify intraprostatic tumor deposits after local radiation therapy results in a high PPV, particularly for PI-RADS 4 and 5 lesions. However, given the high rate of mpMRI-unidentified prostate cancer, the addition of systematic transperineal prostate biopsy information appears necessary to improve the accuracy of mpMRI identification of intraprostatic tumor deposits.

MRI Accuracy in Staging Early and Locally Advanced Rectal Cancer

MRI Accuracy in Staging Early and Locally Advanced Rectal Cancer

Can MRI Be Used as a Sole Diagnostic Modality in Determining Clinical Stage in Cervical Cancer?

The objective of this study was to compare staging by MRI to clinical staging in patients with cervical cancer and to determine the histological accuracy of staging by MRI and examination under anesthesia (EUA) in early stage disease. This was a retrospective cohort study of patients diagnosed with cervical cancer between 2010 and 2020 at the Radboud University Medical Centre, the Netherlands. Pretreatment stage (FIGO 2009) by MRI was compared with staging by EUA. Diagnostic accuracy in terms of sensitivity, specificity, positive, and negative predictive value was calculated for MRI and EUA in patients undergoing surgery (early stage disease) with histological results as a reference standard. A total of 358 patients were included in the study and MRI-based stage differed from EUA stage in 30.7%. In 12.3% this meant a discrepancy in treatment assignment between MRI and EUA. Diagnostic accuracy of MRI in terms of sensitivity and specificity for detecting early stage disease was comparable to EUA in surgical patients. Further analyses showed that premenopausal status, early stage disease and a tumor diameter of <2 cm were associated with improved comparability of MRI and EUA (98%). There is still a large discrepancy between MRI and EUA. In patients with suspected early stage disease, diagnostic accuracy of MRI is similar to EUA, especially for premenopausal women with early stage disease and a tumor diameter of <2 cm.

MRI based composite parameter of multiple tissue types for improved patient-level hemispheric and regional level lateralization in pediatric epilepsy

Although voxel-based morphometry (VBM) of gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) changes aid in epileptic seizure lateralization, type of T1 pulse sequence, preprocessing steps and tissue segmentation methods lead to variation in tissue classification. Here, we test the prediction accuracy of individual MRI based tissue types and a novel composite ratio parameter [(GM + WM)/CSF], sensitive to parenchymal changes and independent of tissue classification variations. Pediatric patients with partial seizures (both simple and complex), but normal and lesion-free MRI were considered (33 patients; unilateral EEG; 17 female / 16 male; age mean ± SD = 11.5 ± 5 years). MRI based seizure lateralization was performed for each patient and verified with EEG findings alone or in combination with seizure semiology. T1 weighted MRI from patients and normal control subjects was spatially transformed to the Talairach atlas and automatically segmented into GM, WM and CSF tissue types. 41 age matched normal controls (11 female / 30 male; age mean ± SD = 14.6 ± 3 years) served as the null distribution to test tissue type deviations across each epilepsy patient. When verified with the patient EEG prediction, WM, GM and CSF had a hemispheric match of 76%, 70% and 55% respectively, while the composite ratio [(GM + WM)/CSF)] showed the highest accuracy of 85%. When EEG findings and seizure semiology were combined, MRI predictions using the composite ratio improved further to 88%. To further localize the epileptic focus, regional level (frontal, temporal, parietal and occipital) MRI predictions were obtained. The composite ratio performed at 88–91% accuracy, revealing regional MRI changes, not predictable with EEG. The results show inconsistent changes in GM and WM in majority of the pediatric epilepsy patients and demonstrate the applicability of the composite ratio [(GM + WM)/CSF)] as a superior predictor, independent of tissue classification variations. Clinical EEG findings combined with seizure semiology, can overcome scalp EEG's limitations and lean towards the MRI lateralization in specific cases.

Diagnostic accuracy of MRI in the detection of intradural extramedullary spinal tumors

Background: The majority of intradural spinal tumors are extramedullary accounting for 40% of all spinal tumors with meningiomas and nerve sheath tumors being the most frequent. Objective: To determine the diagnostic accuracy of MRI in the detection of intradural extramedullary spinal tumors taking histopathology as gold standard. Methodology: This study comprised of 140 patients with clinical suspicion of intradural extramedullary spinal tumor. MRI was performed. The cases were operated and histopathological results were recorded. The results of MRI and histopathology were compared taking histopathology as gold standard. Results: Out of 140 patients, 96 patients (68.6%) had an extramedullary tumor on MRI. After comparison of results of MRI with histopathology, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of MRI were 99%, 95.5%, 97.9%, 97.9% and 97.7% respectively. Conclusion: MRI is a highly accurate, non-invasive, safe and convenient imaging modality for the evaluation of intradural spinal tumors and is valuable for early detection, planning management and guiding surgical biopsies.

Accuracy, precision, and safety of stereotactic, frame-based, intraoperative MRI-guided and MRI-verified deep brain stimulation in 650 consecutive procedures.

Suboptimal lead placement is one of the most common indications for deep brain stimulation (DBS) revision procedures. Confirming lead placement in relation to the visible anatomical target with dedicated stereotactic imaging before terminating the procedure can mitigate this risk. In this study, the authors examined the accuracy, precision, and safety of intraoperative MRI (iMRI) to both guide and verify lead placement during frame-based stereotactic surgery. A retrospective analysis of 650 consecutive DBS procedures for targeting accuracy, precision, and perioperative complications was performed. Frame-based lead placement took place in an operating room equipped with an MRI machine using stereotactic images to verify lead placement before removing the stereotactic frame. Immediate lead relocation was performed when necessary. Systematic analysis of the targeting error was calculated. Verification of 1201 DBS leads with stereotactic MRI was performed in 643 procedures and with stereotactic CT in 7. The mean ± SD of the final targeting error was 0.9 ± 0.3 mm (range 0.1-2.3 mm). Anatomically acceptable lead placement was achieved with a single brain pass for 97% (n = 1164) of leads; immediate intraoperative relocation was performed in 37 leads (3%) to obtain satisfactory anatomical placement. General anesthesia was used in 91% (n = 593) of the procedures. Hemorrhage was noted after 4 procedures (0.6%); 3 patients (0.4% of procedures) presented with transient neurological symptoms, and 1 experienced delayed cognitive decline. Two bleeds coincided with immediate relocation (2 of 37 leads, 5.4%), which contrasts with hemorrhage in 2 (0.2%) of 1164 leads implanted on the first pass (p = 0.0058). Three patients had transient seizures in the postoperative period. The seizures coincided with hemorrhage in 2 of these patients and with immediate lead relocation in the other. There were 21 infections (3.2% of procedures, 1.5% in 3 months) leading to hardware removal. Delayed (> 3 months) retargeting of 6 leads (0.5%) in 4 patients (0.6% of procedures) was performed because of suboptimal stimulation benefit. There were no MRI-related complications, no permanent motor deficits, and no deaths. To the authors' knowledge, this is the largest series reporting the use of iMRI to guide and verify lead location during DBS surgery. It demonstrates a high level of accuracy, precision, and safety. Significantly higher hemorrhage was encountered when multiple brain passes were required for lead implantation, although none led to permanent deficit. Meticulous audit and calibration can improve precision and maximize safety.