Positive Magnetic Resonance Imaging Research Articles

Typical and atypical MRI abnormalities in Wernicke's encephalopathy: Correlation with blood vitamin B1 levels

PurposeClinical features of Wernicke's encephalopathy (WE) confirmed strictly through the low blood vitamin B1 (VB1) levels are limited. This study aimed to analyse magnetic resonance imaging (MRI) findings, and clinical characteristics, in patients with WE who have confirmed low blood VB1 levels. MethodsClinical and laboratory records of 12 consecutive patients with WE admitted to our hospital during the past 11 years were reviewed. The WE diagnosis was confirmed based on low blood VB1 levels and the presence of at least one of the classical triad. ResultsOphthalmoplegia and nystagmus were recorded in 75% and 50% of the patients, respectively. Eleven of 12 patients presented with consciousness disturbance/memory loss. All patients experienced gait disturbances. Eight of the 12 patients exhibited MRI abnormalities at typical sites (the dorsal midbrain [n = 7], medial thalamus [n = 6], mammillary bodies [n = 5], and dorsal pons [n = 5]). Of the 12 patients, six showed abnormalities at atypical sites (the splenium of the corpus callosum [n = 4], fornix [n = 3], cerebral cortex [n = 2], cerebellar vermis [n = 2], and dorsal medulla [n = 1]). Patients with positive MRI abnormalities had significantly lower blood VB1 levels than those without abnormalities (9.5 vs. 16.0 ng/mL). ConclusionsIn cases of confirmed WE with low blood VB1 levels, the corpus callosum, fornix, and cerebral cortex were more frequently involved than in previous studies. MRI abnormalities at both typical and atypical sites were correlated with low blood VB1 levels in WE, suggesting that lower blood VB1 levels are associated with more severe brain damage in patients with WE.

Pediatric cervical spine clearance after blunt trauma and negative CT: What is the role of MRI?

Background and purposeThe cervical spine in children has marked anatomical and biomechanical differences compared to adults, leading to significantly different patterns and incidence of spinal injury, and consequently to different X-ray and computed tomography (CT) imaging recommendations. Magnetic resonance imaging (MRI) has been validated to clear cervical spine trauma in adults, but not in pediatric patients. We hypothesized that MRI findings have a low probability to change management in children with spine trauma and negative CT findings. Materials and methodsWe reviewed records for admitted pediatric patients due to blunt trauma from January 2011 to May 2021, and identified 212 patients who underwent MRI within 3 days of a negative CT. Two neuroradiologists independently reviewed all CT and MRI images for the following categories: fracture, subluxation, spinal canal compromise, ligamentous injury, spinal canal hemorrhage, cord contusion and soft tissue hemorrhage. We identified follow-up MRI examinations as negative or positive for the above categories, and calculated the prevalence of each category as a percentage of cases with negative CT. We also evaluated whether negative and positive MRI groups differed significantly with respect to age and sex of the patients. Results and conclusionsIn our study of 212 children with cervical spine trauma and a negative CT, most follow-up MRI scans were found to be negative (79.9 %). Positive MRI findings consisted mainly of ligamentous sprain without disruption (15.1 %). Ligamentous disruption and epidural or soft tissue hemorrhage were found in 4.5 %, and focal cord contusion in 0.5 %. There was no statically significant difference between negative and positive MRI groups with respect to age (P = 0.45) and sex (P = 0.52). ConclusionIn our patient group with a negative CT, MRI did not significantly impact management nor contribute to cervical spine clearance in children.

Imaging Outcomes of Emergency MR Imaging in Dizziness and Vertigo: A Retrospective Cohort Study.

Patients exhibiting acute dizziness or vertigo often represent a diagnostic challenge, and many undergo neuroimaging for stroke detection. We aimed to demonstrate the imaging outcomes of first-line emergency MR imaging among patients with acute dizziness or vertigo and to determine the clinical risk factors for stroke and other acute pathology. This retrospective study included consecutive patients with acute dizziness or vertigo referred for emergency MR imaging in a tertiary hospital during 5 years. We recorded and analyzed patient characteristics, relevant clinical information, and imaging outcomes. Risk score models were derived to predict which patients were more likely to present with positive MR imaging findings. A total of 1169 patients were included. Acute stroke was found in 17%; other clinically significant pathology, in 8% of patients. In 75% of the patients, emergency MR imaging showed no significant abnormalities. Risk factors for acute stroke included older age, male sex, and a prevalence of cardiovascular risk factors and neurologic signs. Isolated dizziness had no discriminative power on imaging outcomes, and 14% of these patients showed acute stroke. Risk scores had only moderate performance in predicting acute ischemic stroke (receiver operating characteristic area under curve = 0.75) or any significant pathology (receiver operating characteristic area under curve = 0.70). Acute dizziness and vertigo remain challenging even when emergency MR imaging is readily available. One in 4 patients had acute pathology on MR imaging. Predictors for acute pathology (older age, male sex, cardiovascular risk factors, and neurologic signs) may aid in patient selection for MR imaging, optimizing the yield and clinical impact of emergency neuroimaging. Low diagnostic yields of CT and internal acoustic canal MR imaging may offer an opportunity to reduce health care expenditures in the future.

Enhanced contrast imaging with polyamide 6/Fe(OH)3 nanofibrous scaffolds: A focus on high T1 relaxivity

Nanofibers serve as widely employed tissue engineering scaffolds in diverse biomedical applications. When implanted in vivo, it is crucial for tissue engineering scaffolds to be visualizable, enabling the monitoring of their shape, position, and performance. This capability facilitates the effective assessment of implant deformations, displacements, degradations, and functionalities. However, in many biomedical imaging techniques such as magnetic resonance imaging (MRI), the contrast of tissue engineering scaffolds is often inadequate. MRI is particularly notable for its effectiveness in imaging soft tissues. Previous endeavors to enhance the contrast of tissue engineering scaffolds in MRI have involved the use of negative contrast agents (CAs). Nonetheless, negative CAs can result in artifacts, thus favoring the preference for positive CAs due to their ability to generate clearer boundaries. In this study, we successfully prepared composite polyamide 6 nanofibrous scaffolds with ultrafine dispersion Fe(OH)3 nanoparticles using electrospinning and in-situ growth techniques. The relaxation properties of the magnetic nanofibrous scaffolds confirmed the successful production of scaffolds suitable for positive imaging. In vitro cell seeding experiments demonstrated the efficient proliferation and adhesion of endothelial cells and fibroblasts. In vivo studies further revealed the biocompatibility and functionality of the scaffolds. These findings indicate that the prepared PA6/Fe(OH)3 composite nanofibrous scaffolds can enable straightforward, safe, and efficient in vivo positive contrast MRI monitoring, thereby playing a pivotal role in the integration of diagnosis and treatment within tissue engineering scaffolds.

Rational Design of Magnetic Nanoparticles as T1-T2 Dual-Mode MRI Contrast Agents.

Magnetic nanoparticles (MNPs), either paramagnetic or superparamagnetic depending on their composition and size, have been thoroughly studied as magnetic resonance imaging (MRI) contrast agents using in vitro and in vivo biomedical preclinical studies, while some are clinically used. Their magnetic properties responsible in some cases for high magnetization values, together with large surface area-to-volume ratios and the possibility of surface functionalization, have been used in MRI-based diagnostic and theranostics applications. MNPs are usually used as positive (T1) or negative (T2) MRI contrast agents, causing brightening or darkening of selected regions in MRI images, respectively. This review focusses on recent developments and optimization of MNPs containing Gd, Mn, Fe and other lanthanide ions which may function as dual-mode T1-T2 MRI contrast agents (DMCAs). They induce positive or negative contrast in the same MRI scanner upon changing its operational mode between T1-weighted and T2-weighted pulse sequences. The type of contrast they induce depends critically on their r2/r1 relaxivity ratio, which for DMCAs should be in the 2-10 range of values. After briefly discussing the basic principles of paramagnetic relaxation in MNPs, in this review, the basic strategies for the rational design of DMCAs are presented and typical examples are discussed, including in vivo preclinical applications: (1) the use of NPs with a single type of contrast material, Gd- or Mn-based NPs or superparamagnetic NPs with appropriate size and magnetization to provide T2 and T1 contrast; and (2) inclusion of both types of T1 and T2 contrast materials in the same nanoplatform by changing their relative positions.

Walking Dead Macrophage-Based Positive Enhancement MRI for Ultrahighly Efficient Diagnosis of Nephritis.

Nephritis is an inflammatory condition of the glomerulus, and the clinical gold standard for its diagnosis is a kidney biopsy. However, obtaining biopsy results can take several days, which does not meet the requirement of rapid diagnosis, especially for rapidly progressive types. To achieve an effective and noninvasive diagnosis, we propose a nephritis-specific, positive magnetic resonance imaging (MRI) contrast agent based on Gd3+ anchored walking dead macrophage Gd-RAW. Gd-RAW exhibits high selectivity for inflammatory renal parenchyma and provides comparable results to histopathology methods. The Gd-RAW-based MRI contrast agent reduces the diagnostic time of nephritis from 14 days of biopsy to 1 h. Furthermore, in a unilateral nephritis model constructed by increasing the glycerol concentration, the T1WI of renal parenchyma exhibits an increased signal-to-noise ratio, which is crucial for evaluating nephritic severity. This work promotes rapid diagnosis of nephritis and potentially provides sufficient evidence for clinicians to offer timely treatment to patients. The methodology of paramagnetic ion-anchored macrophage corpse also opens up new prospects for designing more specific and biosafe MRI contrast agents.

The first study of real-world efficacy and safety of Natalizumab (Tysabri®) in Iran

Objectives: Natalizumab is an injectable DMT (disease-modifying therapy) which used for RRMS (relapsing-remitting multiple sclerosis) since 2006. The drug has been available in Iran since 2014. Introduction: This study was aimed to evaluate the real-world effectiveness of Natalizumab in a referral center in Tehran, Iran. This study is the first real world analysis of efficacy and safety of Natalizumab in our country. Methods: In this retrospective study, patients with RRMS were investigated in a high-volume center in Tehran from 2019 to 2021. MS (Multiple Sclerosis) patients under treatment with Natalizumab who have received at least 3 infusions of the drug and had completed follow-up data, have been evaluated for safety and efficacy of Natalizumab. Results: 100 patients were included in the final analysis. The mean follow-up time was 20 months (6–33 months). The median EDSS (Expanded Disability Status Scale) score of patients reached to 2 from 2.5 after the treatment course (P < 0.0001). The annualized relapse rate (ARR) decreased from 0.81 (95% CI: 0.73–0.87) to 0.023 (95% CI 0.009–0.061). The median JCV (John Cunningham virus) index remained unchanged before treatment 0.85 (IQR: 0.21–2.41) compare to after the treatment 0.85 (IQR: 0.21–2.31). The number of patients with active brain and cervical MRI (Magnetic Resonance Imaging) lesions decreased significantly (P = 0.001). NEDA-3 (No evidence of disease activity) was improved from 9% to 87% after the treatment with Natalizumab. No serious adverse events except than one progressive multifocal encephalopathy (PML) case have been found. The main reasons of switching from Natalizumab to the other DMDs (Disease Modifying Drugs) were positive JC index, starting phase, noncompliance, pregnancy, MRI activity and seroconversion after starting the drug. Conclusion: Natalizumab is a safe and effective choice in RRMS patients for reducing relapse rate, disability score, active MRI lesion, and improving the NEDA (No evidence of disease activity).

Predictive Factors for Extracapsular Extension of Prostate Cancer to Select the Candidates for Nerve-sparing Radical Prostatectomy.

Nerve-sparing radical prostatectomy (NSRP) for prostate cancer (PC) enables better postoperative recovery of continence and potency but may increase the risk of positive surgical margins. This study aimed to investigate preoperative predictive factors for extracapsular extension (ECE) of PC to select patients for NSRP. We retrospectively evaluated 288 patients with PC (576 lobes) diagnosed with 12-core transrectal ultrasound-guided biopsy and magnetic resonance imaging (MRI) who underwent laparoscopic or robot-assisted radical prostatectomy at our institution. Surgical specimens and preoperative parameters (prostate-specific antigen, prostate volume, biopsy and MRI findings, preoperative therapy) were analyzed. Of 576 prostate lobes, the incidence Ipsilateral ECE was identified in 97 (16.8%) lobes. The higher number of unilateral positive biopsy cores, the highest Gleason score 8 or more and positive unilateral findings on MRI are significant higher in prostate sides with ECE in univariate analysis. In multivariate analysis, positive unilateral MRI findings (odds ratio [OR], 2.86; p < 0.001) and unilateral biopsy positive core ≥ 3 (OR, 3.73; p < 0.001) were independent predictors of unilateral ECE. The detection rate of unilateral ECE in those cases with two factors (side-specific positive biopsy core 2 or less and side-specific MRI findings negative) was 7.1% (19/269). Patients with fewer unilateral positive biopsy cores and negative unilateral MRI findings might be good candidates for NSRP.

MRI findings of peroneal tendon tears do not necessarily correlate to clinical findings in paediatric and adolescent patients.

Pathologic abnormality of the peroneal tendons are thought to be an under-appreciated source of vague ankle and hindfoot pain in paediatric patients, partly because they can be difficult to diagnose and differentiate from lateral ankle ligament injuries. While magnetic resonance imaging (MRI) is the primary imaging modality used to detect peroneal tendon pathology, previous studies in adults have found that positive MRIs demonstrate a positive predictive value (PPV) of associated clinical findings around 48%. There are no similar known published studies in the paediatric population. Our objective was to determine the positive predictive value of peroneal tendon pathology as diagnosed by MRI as related to positive clinical exam findings in the paediatric and adolescent population. This IRB approved retrospective study was conducted at a tertiary children's hospital. Inclusion criteria included patients under 18years from our tertiary care institution with (a) ankle MRI findings indicating pathology of the peroneus brevis/longus tendons confirmed by a board certified paediatric musculoskeletal radiologist and (b) formal review of the clinical examination by a fellowship trained paediatric orthopaedic surgeon. Patients with congenital deformities or previous surgical intervention of the lateral ankle were excluded. Forty-seven patients (with 48 MRIs) met inclusion criteria over a tenyear period. The majority of the positive MRI scans (70%) demonstrated a peroneus brevis split tear. Of the patients with positive findings on MRI, 17 patients had an associated positive clinical exam. The positive predictive value of MRI for peroneal tendon tears with positive clinical findings was 35.41% (95% confidence interval = 31.1% to 41.6%). There were 31 patients with MRI positive findings with a negative clinical exam. Despite having a negative clinical exam, a high percentage of patients had positive MRI findings suggestive of peroneal tendon pathology which confirms findings of adult populations demonstrating a high rate of incidental finding of peroneal tendon pathology on MRI in paediatric patients.

A Cross-sectional Study on Neuroimaging in Epilepsy: Diagnostic Value of T2 Relaxometry in Mesial Temporal Lobe Epilepsy

Introduction: The use of Magnetic Resonance Imaging (MRI) T2 relaxometry and spectroscopy has added new dimensions to the imaging of Temporal Lobe Epilepsy (TLE). Advanced techniques like MRI diffusion and MRI perfusion are new additions to the MRI protocol for epilepsy. Aim: To study the diagnostic value of T2 relaxation time in Electroencephalogram (EEG) confirmed seizure cases. Materials and Methods: A single-centre, cross-sectional study was conducted at Department of Radiodiagnosis, Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India, from December 2020 to November 2022 at a tertiary care hospital. All patients were subjected to MRI with a special epilepsy protocol and T2 relaxometry. Hippocampal T2 relaxation values for each slice were measured by placing a Region of Interest (ROI) on the representative image obtained from the T2 relaxometry sequence, focusing on the hippocampus in both the control and study groups. The control group (n=30) consisted of healthy volunteers, whereas the case group (n=36) comprised patients presenting with a history of seizures with positive MRI and EEG findings. Mean T2 relaxation time was calculated in each ROI, and an average was derived. Mean and Standard Deviation (SD) were calculated for the continuous variables, while ratios and proportions were calculated for the categorical variables. To determine the association of T2 relaxometry values in the study and control groups, an unpaired t-test was used. Results: The mean age of participants was 25.14±9.35 years (ranging from 9 to 51 years). The male-to-female ratio was 1.25:1. Hippocampal atrophy (32 out of 36 cases) and T2 signal alteration (30 out of 36 cases) were the most commonly identified features in Mesial Temporal Sclerosis (MTS). MRI without T2 relaxometry had a sensitivity of 94%. In two cases, where only mild hippocampal atrophy was identified in the conventional MRI sequence, making the diagnosis dubious, T2 relaxometry revealed increased T2 relaxation time in the head of the hippocampus and guided a proper diagnosis. EEG was able to lateralise seizures in 8 out of 13 right MTS cases (61.5%), 10 out of 17 left MTS cases (58.9%), and 5 out of 6 cases of bilateral MTS (83%). Conclusion: T2 relaxometry allows quantification of hippocampal signal intensity, allowing the detection of even subtle changes in signal intensity that are difficult to perceive by visual assessment.

Artificial intelligence for the detection of sacroiliitis on magnetic resonance imaging in patients with axial spondyloarthritis.

Magnetic resonance imaging (MRI) is important for the early detection of axial spondyloarthritis (axSpA). We developed an artificial intelligence (AI) model for detecting sacroiliitis in patients with axSpA using MRI. This study included MRI examinations of patients who underwent semi-coronal MRI scans of the sacroiliac joints owing to chronic back pain with short tau inversion recovery (STIR) sequences between January 2010 and December 2021. Sacroiliitis was defined as a positive MRI finding according to the ASAS classification criteria for axSpA. We developed a two-stage framework. First, the Faster R-CNN network extracted regions of interest (ROIs) to localize the sacroiliac joints. Maximum intensity projection (MIP) of three consecutive slices was used to mimic the reading of two adjacent slices. Second, the VGG-19 network determined the presence of sacroiliitis in localized ROIs. We augmented the positive dataset six-fold. The sacroiliitis classification performance was measured using the sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). The prediction models were evaluated using three-round three-fold cross-validation. A total of 296 participants with 4,746 MRI slices were included in the study. Sacroiliitis was identified in 864 MRI slices of 119 participants. The mean sensitivity, specificity, and AUROC for the detection of sacroiliitis were 0.725 (95% CI, 0.705-0.745), 0.936 (95% CI, 0.924-0.947), and 0.830 (95%CI, 0.792-0.868), respectively, at the image level and 0.947 (95% CI, 0.912-0.982), 0.691 (95% CI, 0.603-0.779), and 0.816 (95% CI, 0.776-0.856), respectively, at the patient level. In the original model, without using MIP and dataset augmentation, the mean sensitivity, specificity, and AUROC were 0.517 (95% CI, 0.493-0.780), 0.944 (95% CI, 0.933-0.955), and 0.731 (95% CI, 0.681-0.780), respectively, at the image level and 0.806 (95% CI, 0.729-0.883), 0.617 (95% CI, 0.523-0.711), and 0.711 (95% CI, 0.660-0.763), respectively, at the patient level. The performance was improved by MIP techniques and data augmentation. An AI model was developed for the detection of sacroiliitis using MRI, compatible with the ASAS criteria for axSpA, with the potential to aid MRI application in a wider clinical setting.

P008 - Prostate-specific antigen (PSA) level and international prostate symptom score (IPSS) as stratifiers for positive magnetic resonance imaging (MRI) results in biopsy-naïve men

P008 - Prostate-specific antigen (PSA) level and international prostate symptom score (IPSS) as stratifiers for positive magnetic resonance imaging (MRI) results in biopsy-naïve men

Added Value of Prostate-specific Antigen Density in Selecting Prostate Biopsy Candidates Among Men with Elevated Prostate-specific Antigen and PI-RADS ≥3 Lesions on Multiparametric Magnetic Resonance Imaging of the Prostate: A Systematic Assessment by PI-RADS Score

BackgroundA significant proportion of patients with positive multiparametric magnetic resonance imaging (mpMRI; Prostate Imaging-Reporting and Data System [PI-RADS] scores of 3–5) have negative biopsy results. ObjectiveTo systematically assess all prostate-specific antigen density (PSAD) values and identify an appropriate cutoff for identification of patients with positive mpMRI who could potentially avoid biopsy on the basis of their PI-RADS score. Design, setting, and participantsThe study included a cohort of 1341 patients with positive mpMRI who underwent combined targeted and systematic biopsies. Outcome measurements and statistical analysisMultivariable logistic regression analysis (MVA) was used to assess the association between PSAD and the risk of clinically significant prostate cancer (csPCa, grade group ≥2) after adjusting for confounders. We used locally weighted scatterplot smoothing to explore csPCa risk according to PSAD and PI-RADS scores. PSAD utility was observed only for patients with PI-RADS 3 lesions, so we plotted the effect of each PSAD value as a cutoff for this subgroup in terms of biopsies saved, csPCa cases missed, and clinically insignificant PCa (ciPCa, grade group 1) cases not detected. Results and limitationsOverall, 667 (50%) csPCa cases were identified. On MVA, PSAD independently predicted csPCa (odds ratio 1.57; p < 0.001). For PI-RADS ≥4 lesions, the csPCa risk was ≥40% regardless of PSAD. Conversely, among patients with PI-RADS 3 lesions, csPCa risk ranged from 0% to 60% according to PSAD values, and a PSAD cutoff of 0.10 ng/ml/cm3 corresponded to a threshold probability of 10% for csPCa. Using this PSAD cutoff for patients with PI-RADS 3 lesions would have saved 32% of biopsies, missed 7% of csPCa cases, and avoided detection of 34% of ciPCa cases. Limitations include selection bias and the high experience of the radiologists and urologists involved. ConclusionsPatients with PI-RADS ≥4 lesions should undergo prostate biopsy regardless of their PSAD, while PSAD should be used to stratify patients with PI-RADS 3 lesions. Using a threshold probability of 10% for csPCa, our data suggest that the appropriate strategy is to avoid biopsy in patients with PI-RADS 3 lesions and PSAD <0.10 ng/ml/cm3. Our results also provide information to help in tailoring an appropriate strategy for every patient with positive mpMRI findings. Patient summaryWe investigated whether a cutoff value for PSAD (prostate-specific antigen density) could identify patients with suspicious prostate lesions on MRI (magnetic resonance imaging) who could avoid biopsy according to the PI-RADS score for their scan. We found that patients with PI-RADS ≥4 should undergo prostate biopsy regardless of their PSAD. A PSAD cutoff of 0.10 should be used to stratify patients with PI-RADS 3.

Prostate Biopsies Can Be Omitted in Most Patients with a Positive Stockholm3 Test and Negative Prostate Magnetic Resonance Imaging

BackgroundMagnetic resonance imaging (MRI) combined with the Stockholm3 test can be used to inform biopsy decision-making in patients with a suspicion of prostate cancer. ObjectiveTo determine the consequence of omitting biopsies in men with a positive Stockholm3 test and a negative MRI. Design, setting, and participantsIn a real-life setting, 438 men with a positive Stockholm3 test and a negative MRI underwent systematic biopsies from 2017 to 2020. Outcome measurements and statistical analysisThe Stockholm3 test result is a percentage risk score with or without a prostate volume cutoff. The main outcomes were the number of clinically significant (Gleason grade group [GG] ≥2) and nonsignificant (GG 1) prostate cancers. Results and limitationsMedian prostate-specific antigen was 4.5 ng/ml (interquartile range 2.8–6.4 ng/ml) and the median age was 69 yr. Systematic biopsies detected grade group (GG) ≥2 disease in 48 men (11%, 95% confidence interval [CI] 8.4–14.2%) and GG 1 disease in 94 men (21.5%, 95% CI 17.9–25.6%). Of 256 patients without a volume cutoff in the test report, GG ≥2 was detected in 37 men (14.5%, 95% CI 10.7–19.3%). Omitting biopsies in patients with a volume cutoff would miss 11 GG ≥2 cases (6%, 95% CI 3.4–10.5%), reduce the number of GG 1 cases detected by 37 (39.4%, 95% CI 30.1–49.5%), and avoid a total of 182 biopsies (41.6%, 95% CI 37.0–46.2%). Limitations include the lack of follow-up data. ConclusionsSystematic biopsies can be omitted in patients with a positive Stockholm3 test and a negative MRI when there is a volume cutoff in the test report. With no volume cutoff, biopsies can be considered with shared decision-making. Patient summaryWhen investigated on suspicion of prostate cancer with a positive Stockholm3 test and a negative MRI (magnetic resonance imaging), prostate biopsies are only necessary for a subgroup of patients. This can spare some men from undergoing biopsies and reduce the detection of clinically insignificant cancers.

Brain magnetic resonance imaging (MRI) findings in central precocious puberty patients: is routine MRI necessary for newly diagnosed patients?

The overall incidence of central precocious puberty (CPP) has increased in recent decades, and brain magnetic resonance imaging (MRI) evaluations are recommended in cases of suspected brain lesions. This study aimed to investigate the prevalence of MRI abnormalities and to evaluate the need for routine brain MRI in patients with newly diagnosed CPP. This retrospective study reviewed the data of patients newly diagnosed with CPP who underwent routine pituitary MRI at Korea University Anam Hospital from March 2020 to September 2021. A total of 199 girls and 24 boys was enrolled in this study. Positive MRI findings were categorized as abnormal pituitary, nonpituitary incidental, and pathological. In addition, we investigated the incidence of MRI abnormalities and evaluated their associations with clinical and biochemical factors. Positive brain MRI findings were observed in 84 patients (37.7%). Pituitary abnormalities were found in 54 patients (24.2%), with Rathke cleft cysts being the most common (16.1%). Incidental nonpituitary findings were observed in 29 patients (13.0%), while a pathological brain lesion (diagnosed as hypothalamic hamartoma) was observed in only 1 female patient (0.4%). No significant differences in sex or age were found in incidence of pituitary abnormalities or nonpituitary incidental findings. Compared with headache controls, significant associations were observed between abnormal pituitary findings on MRI and CPP (unadjusted odds ratio, 3.979; 95% confidence interval, 1.726-9.173). True pathological findings were rare, even though the prevalence of abnormalities on pituitary MRI in patients with CPP was relatively high. Considering its cost-effectiveness, MRI screenings should be carefully considered in patients with CPP.

Histomic and transcriptomic features of MRI-visible and invisible clinically significant prostate cancers are associated with prognosis.

Magnetic resonance imaging (MRI) is increasingly used to triage patients for prostate biopsy. However, 9% to 24% of clinically significant (cs) prostate cancers (PCas) are not visible in MRI. We aimed to identify histomic and transcriptomic determinants of MRI visibility and their association to metastasis, and PCa-specific death (PCSD). We studied 45 radical prostatectomy-treated patients with csPCa (grade group [GG]2-3), including 30 with MRI-visible and 15 with MRI-invisible lesions, and 18 men without PCa. First, histological composition was quantified. Next, transcriptomic profiling was performed using NanoString technology. MRI visibility-associated differentially expressed genes (DEGs) and Reactome pathways were identified. MRI visibility was classified using publicly available genes in MSK-IMPACT and Decipher, Oncotype DX, and Prolaris. Finally, DEGs and clinical parameters were used to classify metastasis and PCSD in an external cohort, which included 76 patients with metastatic GG2-4 PCa, and 84 baseline-matched controls without progression. Luminal area was lower in MRI-visible than invisible lesions and low luminal area was associated with short metastasis-free and PCa-specific survival. We identified 67 DEGs, eight of which were associated with survival. Cell division, inflammation and transcriptional regulation pathways were upregulated in MRI-visible csPCas. Genes in Decipher, Oncotype DX and MSK-IMPACT performed well in classifying MRI visibility (AUC = 0.86-0.94). DEGs improved classification of metastasis (AUC = 0.69) and PCSD (AUC = 0.68) over clinical parameters. Our data reveals that MRI-visible csPCas harbor more aggressive histomic and transcriptomic features than MRI-invisible csPCas. Thus, targeted biopsy of visible lesions may be sufficient for risk stratification in patients with a positive MRI.

Initial Experience of 18 F-FET PET-MR Image Fusion for Evaluation of Recurrent Primary Brain Tumors.

Background An accurate monitoring technique is crucial in brain tumors to choose the best treatment approach after surgery and/or chemoradiation. Radiological assessment of brain tumors is widely based on the magnetic resonance imaging (MRI) modality in this regard; however, MRI criteria are unable to precisely differentiate tumoral tissue from treatment-related changes. This study was conducted to evaluate whether fused MRI and O-(2- 18 F-fluoroethyl)-L-tyrosine ( 18 F-FET) positron emission tomography (PET) can improve the diagnostic accuracy of the practitioners to discriminate treatment-related changes from true recurrence of brain tumor. Methods We retrospectively analyzed 18 F-FET PET/computed tomography (CT) of 11 patients with histopathologically proven brain tumors that were suspicious for recurrence changes after 3 to 4 months of surgery. All the patients underwent MRI and 18 F-FET PET/CT. As a third assessment, fused 18 F-FET PET/MRI was also acquired. Finally, the diagnostic accuracy of the applied modalities was compared. Results Eleven patients aged 27 to 73 years with a mean age of 47 ± 13 years were enrolled. According to the results, 9/11 cases (82%) showed positive MRI and 6 cases (55%) showed positive PET/CT and PET/MRI. Tumoral recurrence was observed in six patients (55%) in the follow-up period. Based on the follow-up results, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 64, 85, 25, 67, and 50%, respectively, for MRI alone and 91, 85, 100, 100, and 80%, respectively, for both PET/CT and PET/MRI. Conclusion This study found that 18 F-FET PET-MR image fusion in the management of brain tumors might improve recurrence detection; however, further well-designed studies are needed to verify these preliminary data.

The Rationality to Requesting in-ward Magnetic Resonance Imaging Investigation.

Magnetic Resonance imaging (MRI) is a valuable diagnostic tool by its non-invasive/non-ionizing nature. This study aims to determine justification of MRI in hospitalized patients at a tertiary provincial referent medical center in a one-year period. In the present retrospective and descriptive cross-sectional study, 438 admitted patients referred for MRI during 2017 were selected using systematic random sampling. The age, gender, investigated organ, the specialty of requesting physician, MRI with and without contrast, MRI diagnostic outcome were collected using checklists. Descriptive statistics and chi-square test were used for data analysis. The mean age of the patients was 42±26 years-old and female represented 53% of enrolled patients. The most and less prevalent investigated organs were the cerebrum and the orbit. After excluding cancer diagnosis, cancer staging, and therapeutic follow-up exams, MRI request was oriented in 64.3% and 77.2% of positive results was concordant with aforementioned diagnostic orientation (P<0.001). Oriented diagnostic MRI requesting is influenced by age, medical specialists and, investigated organ (P<0.001). The positive MRI is influenced significantly by oriented MRI request, gender, medical specialists and investigated organ (P<0.001). The diagnosis concordance of MRI is influenced significantly by oriented MRI request, medical specialists and investigated organ (P<0.001). Appropriate implementation of medical imaging requires boosting employed rationality by the concerned physicians. The current suboptimal results to requesting MRI rationality should mandate supplementary educational programs as to incite the medical corpus more closely implementing the published medical practice guidelines.

Magnetic Nanoparticle-Based High-Performance Positive and Negative Magnetic Resonance Imaging Contrast Agents.

In recent decades, magnetic nanoparticles (MNPs) have attracted considerable research interest as versatile substances for various biomedical applications, particularly as contrast agents in magnetic resonance imaging (MRI). Depending on their composition and particle size, most MNPs are either paramagnetic or superparamagnetic. The unique, advanced magnetic properties of MNPs, such as appreciable paramagnetic or strong superparamagnetic moments at room temperature, along with their large surface area, easy surface functionalization, and the ability to offer stronger contrast enhancements in MRI, make them superior to molecular MRI contrast agents. As a result, MNPs are promising candidates for various diagnostic and therapeutic applications. They can function as either positive (T1) or negative (T2) MRI contrast agents, producing brighter or darker MR images, respectively. In addition, they can function as dual-modal T1 and T2 MRI contrast agents, producing either brighter or darker MR images, depending on the operational mode. It is essential that the MNPs are grafted with hydrophilic and biocompatible ligands to maintain their nontoxicity and colloidal stability in aqueous media. The colloidal stability of MNPs is critical in order to achieve a high-performance MRI function. Most of the MNP-based MRI contrast agents reported in the literature are still in the developmental stage. With continuous progress being made in the detailed scientific research on them, their use in clinical settings may be realized in the future. In this study, we present an overview of the recent developments in the various types of MNP-based MRI contrast agents and their in vivo applications.

Performance of Non-EPI DW MRI for Pediatric Cholesteatoma Follow-Up.

To evaluate the accuracy, sensitivity, and specificity of nonecho planar (non-EPI) diffusion-weighted (DW) magnetic resonance imaging (MRI)to detect residual cholesteatoma in children. Retrospective study. Tertiary comprehensive hospital. Children operated on for a first-stage cholesteatoma procedure from 2010 to 2019 were included. MRIs were performed with non-EPIDW sequences. Initial reports were collected, indicating the presence or absence of hyperintensity suggestive of cholesteatoma. Three hundred twenty-three MRIs were correlated with the subsequent surgery (66%) or year-later MRI (21%), or were considered accurate if performed 5 years or more after the last surgery (13%). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging procedure for the detection of cholesteatoma were calculated. Two hundred twenty-fourchildren with mean age of 9 ± 4 years old presented with cholesteatoma. MRIs were performed 27 ± 24 months after surgery. Residual cholesteatoma was diagnosed in 35%. The sensitivity, specificity, PPV, and NPV of MRI were 62%, 86%, 74%, and 78%, respectively. Accuracy, sensitivity, and specificity increased significantly over time (multivariate analysis). The mean delay after last surgery was of 30 ± 2.0 months for accurate MRI (true positive or negative) versus 17 ± 2.0 months for nonaccurate (false positive or negative) MRIs (p < .001). However, long the delay after the last surgery, the sensitivity of non-EPI diffusion sequence MRI in children has limitations for the detection of residual cholesteatoma. Surveillance for residual cholesteatoma should incorporate findings at primary surgery, surgeon experience, a low threshold for second-look procedures, and routine imaging.