Areas Of High Signal Intensity Research Articles

Brainstem hemorrhage associated with venous hypertensive myelopathy without dural arteriovenous fistula: illustrative case.

Venous hypertensive myelopathy (VHM), formerly known as "Foix-Alajouanine syndrome," is a spinal cord dysfunction caused by impaired perfusion of the spinal cord. Most cases are attributed to spinal dural arteriovenous fistulas (dAVFs), but there are scattered reports of VHM without concomitant dAVF. Furthermore, no cases of VHM associated with intracranial hemorrhage exist. A 68-year-old man with a history of hypertension presented with a sudden headache, proximal paresis of the left upper extremity, impaired pain and temperature sensation in the right upper extremity, dysphagia, and dysarthria. Computed tomography scans showed intraparenchymal hemorrhage in the left medulla oblongata and a linear, continuous high-density area extending from the medulla oblongata to the cervical spinal cord. Magnetic resonance images showed cervical spondylosis at the C5-6 and C6-7 levels, with high signal intensity changes from the medulla oblongata to the lower cervical cord on T2-weighted images. Cerebral angiography showed no abnormal vessels. Conservative treatment gradually improved symptoms and the high signal intensity areas. This case highlights intracranial hemorrhage occurring from extracranial causes and the possibility of VHM due to cervical spondylosis. When hemorrhagic lesions of the craniovertebral junction or spinal parenchymal lesions are encountered, the underlying pathology should be investigated thoroughly and systematically. https://thejns.org/doi/10.3171/CASE24441.

Treatment Outcomes of PED for Unruptured Aneurysms of Internal Carotid Artery: Comparison of PED-Flex and PED-Shield.

There is a lack of data regarding the safety and effectiveness of implanting the Pipeline Embolization Device with Shield technology (PED-Shield) compared with the previous generation of Pipeline (PED-Flex). This retrospective single-center study aimed to compare treatment outcomes between the PED-Shield and PED-Flex for treating unruptured internal carotid artery aneurysms. The PED-Flex was used in 62 procedures (67 aneurysms, 59 patients) and the PED-Shield in 53 procedures (59 aneurysms, 58 patients). The mean aneurysm diameter was significantly lower in the PED-Shield group than in the PED-Flex group (11.9 ± 7.0 mm vs. 15.2 ± 6.9 mm, p < 0.001). At the 12-month follow-up, the complete angiographic occlusion rate was 72.1% and 72.3% in the PED-Flex and PED-Shield groups, respectively (p = 0.9808). Limited to aneurysms larger than 10 mm, 70.6% and 68.0%, respectively (p = 0.8175). The incidence of more than three high signal intensity areas on diffusion-weighted imaging after treatment was significantly lower in the PED-Shield group than in the PED-Flex group (27.7% vs. 67.7%; p < 0.001). Limited to aneurysms larger than 10 mm, 41.1% and 69.6%, respectively (p < 0.0117). Symptomatic ischemic complications occurred within 30 days of four PED-Flex procedures (6.5%) and one PED-Shield procedure (2.0%) (p = 0.2315). Limited to aneurysms larger than 10 mm, 1.8% and 3.2%, respectively (p = 0.6677). The incidence of mRS score worsening at 6 months was 3.2% and 1.9% in the PED-Flex and PED-Shield groups, respectively (p = 0.6534). The PED-Shield can achieve outcomes equivalent to or better than the PED-Flex. Further large-scale studies are warranted to confirm our findings.

Specific brain MRI features of constitutional mismatch repair deficiency syndrome in children with high-grade gliomas.

Children with constitutional mismatch repair deficiency (CMMRD) syndrome have an increased risk of high-grade gliomas (HGG), and brain imaging abnormalities. This study analyzes brain imaging features in CMMRD syndrome children versus those with HGG without CMMRD. Retrospective comparative analysis of brain imaging in 30 CMMRD children (20 boys, median age eight years, 22 with HGG), seven with Lynch syndrome (7 HGG), 39 with type 1 neurofibromatosis (NF1) (four with HGG) and 50 with HGG without MMR or NF1 pathogenic variant ("no-predisposition" patients). HGG in CMMRD and Lynch patients were predominantly hemispheric (versus midline) compared to NF1 and no-predisposition patients (91% and 86%, vs 25% and 54%, p = 0.004). CMMRD-associated tumors often had ill-defined boundaries (p = 0.008). All CMMRD patients exhibited at least one developmental venous anomaly (DVA), versus 14%, 10%, and 6% of Lynch, NF1, and no-predisposition patients (p < 0.0001). Multiple DVAs were observed in 83% of CMMRD patients, one NF1 patient (3%), and never in other groups (p < 0.0001). Cavernomas were discovered in 21% of CMMRD patients, never in other groups (p = 0.01). NF1-like focal areas of high T2-FLAIR signal intensity (FASI) were more prevalent in CMMRD patients than in Lynch or no-predisposition patients (50%, vs 20% and 0%, respectively, p < 0.0001). Subcortical and ill-limited FASI, possibly involving the cortex, were specific to CMMRD (p < 0.0001) and did not evolve in 93% of patients (13/14). Diffuse hemispherically located HGG associated with multiple DVAs, cavernomas, and NF1-like or subcortical FASI strongly suggests CMMRD syndrome compared to children with HGG in other contexts. The radiologic suggestion of CMMRD syndrome when confronted with HGGs in children may prompt genetic testing. This can influence therapeutic plans. Therefore, imaging features could potentially be incorporated into CMMRD testing recommendations. Using imaging to detect CMMRD syndrome early may improve patient care. CMMRD features include: hemispheric HGG with multiple developmental venous anomalies and NF1-like or subcortical areas with high T2-FLAIR intensity. We propose novel imaging features to improve the identification of potential CMMRD patients.

Evaluation of left atrial function and tissue after pulmonary vein isolation - initial results of The EVALUATE-PVI STUDY

Abstract Background Pulmonary vein (PV) isolation (PVI) by catheter ablation is a well-established treatment for atrial fibrillation (AF). Currently, the direct and long-term impact of ablation injury on left atrial (LA) function and tissue is poorly understood. Purpose The aim of this study is to evaluate the acute and long-term impact of radiofrequency (RF) PVI ablation on LA function and corresponding tissue changes as assessed with cardiac magnetic resonance imaging (CMR). Methods Seventeen patients (76.5% male, 60.8±9.7 years) with AF who underwent primo RF PVI as part of the EVALUATE-PVI STUDY underwent three sequential CMR scans prior to PVI, and &amp;lt;72 hours and 3 months after PVI ablation. T2-weighted turbo spin echo imaging was applied to assess post-ablation edema. High-resolution three-dimensional (3D) late gadolinium-enhancement (LGE) images were acquired to study acute LA wall injury and chronic fibrosis formation. LA volume and function were derived from two-chamber and four-chamber SSFP cine images. Maximum and minimal LA volume was indexed to body surface area to compute LAVimax and LAVimin. Longitudinal LA strain was calculated using feature tracking, and subdivided into reservoir, conduit, and contractile strain. Results Acutely post-PVI, T2w images showed increased signal intensity and thickening throughout the entire LA wall. LGE images showed diffuse increased signal intensity, without distinct focal high signal intensity areas (Fig. 1). Functional assessment at this stage showed significantly reduced LA emptying fraction (EF), LA reservoir, and contractile strain compared to pre-PVI (54.8±11.1% vs. 48.5±7.9%, p=0.01; 18.6±5.6% vs. 14.6±2.0%, p&amp;lt;0.01; 8.5±3.5% vs. 5.2±1.8%, p&amp;lt;0.001, respectively), while LA conduit strain, LAVimin, and LAVimax did not differ significantly (Fig. 2). The LGE images acquired at 3 months, displayed clear, focal, high signal intensity areas surrounding the PVs. At this stage post-PVI, a significant increase in LA strain was observed (LA reservoir strain 14.6±2.0% vs. 16.9±3.5%, p&amp;lt;0.01; and contractile strain 5.2±1.8% vs. 6.7±2.9%, p&amp;lt;0.01; respectively). LAVimax was significantly reduced at 3 months compared to acutely post-PVI (Fig. 2). LAVimin and LA conduit strain did not differ between the pre- and post-PVI stages. Conclusion PVI ablation resulted in temporary reduced LA function acutely post-PVI, likely due to edema and thickening of the LA wall. At three months, LGE images revealed clearly visible increased signal intensity in the ablated segments. At this stage, LA function improved, though full recovery did not occur as evidenced by the persistent slightly reduced contractile strain, possibly due to the ablation-induced loss of LA myocardium and formation of fibrosis. The decrease in LAVimax indicates reverse remodeling as a result of the ablation.

RADT-41. PREDICTION OF TREATMENT OUTCOME IN GAMMA KNIFE RADIOSURGERY OF BENIGN MENINGIOMAS

Abstract Objective This study aimed to assess the predictability of machine learning (ML) ensemble models for the success of Gamma Knife radiosurgery (GKRS) on non-skull base benign meningiomas. METHODS A total of 331 non-skull base benign meningiomas treated primarily with GKRS between 1997 and 2015 were retrospectively analyzed. When a tumor remained not larger than 125% of the initial volume at the last imaging follow-up and no significant change in the high signal intensity area around the tumor, it was classified as 'treatment success (TS).' Univariate correlation and multivariate logistic regression analyses were performed to identify statistically significant prognostic factors. Four ensemble algorithms were trained to predict the outcome of GKRS. The importance of features related to TS was analyzed. RESULTS The median MR imaging follow-up period was 8.6 years. The tumor control and signal change rates were 91.5% and 16.3%, respectively, and the TS rate was 77.6%. The conventional multivariate logistic regression model showed 83.7% accuracy and 37.8% specificity. The ML models had accuracies between 78.0% and 82.2% and specificities between 30.3% and 80.7%, and they were similar to those of conventional logistic regression analyses. The smaller brain volume absorbed more than 14 Gy, and the absence of signal change before GKRS was a favorable prognostic factor for TS in all models. The bagging algorithm with selected features showed the best specificity of 80.7% and the most significant AUC of 0.723. CONCLUSION A bagging ensemble algorithm with selected features had better specificity with similar accuracy than conventional multivariate logistic regression in predicting GKRS outcomes for non-skull base meningiomas.

MRI characteristics of lumbosacral dural arteriovenous fistulas.

Spinal dural arteriovenous fistulas located in the lumbosacral region are rare and present with nonspecific clinical signs. The purpose of this study was to find out the specific radiologic features of these fistulas. We retrospectively reviewed the clinical and radiological data of 38 patients diagnosed with lumbosacral spinal dural arteriovenous fistulas in our institution from September 2016 to September 2021. All patients underwent time-resolved contrast-enhanced three-dimensional MRA and DSA examinations, and were treated with either endovascular or neurosurgical strategies. Most of the patients (89.5%) had motor or sensory disorders in both lower limbs as the first symptoms. On MRA, the dilated filum terminale vein or radicular vein was seen in 23/30 (76.7%) patients with lumbar spinal dural arteriovenous fistulas and 8/8 (100%) patients with sacral spinal dural arteriovenous fistulas. T2W intramedullary abnormally high signal intensity areas were found in all lumbosacral spinal dural arteriovenous fistula patients, with involvement of the conus present in 35/38 (92.1%) patients. The "missing piece sign" in the intramedullary enhancement area was seen in 29/38 (76.3%) patients. Dilatation of the filum terminale vein or radicular vein is powerful evidence for diagnosis of lumbosacral spinal dural arteriovenous fistulas, especially for sacral spinal dural arteriovenous fistulas. T2W intramedullary hyperintensity in the thoracic spinal cord and conus, and the missing-piece sign could be indicative of lumbosacral spinal dural arteriovenous fistula.

Primary synovial sarcoma of the shoulder: Case report of the “triple sign” on proton density magnetic resonance imaging

The first case of synovial sarcoma was published in 1893. The disease is a type of primary malignancy of the soft tissues. It is a rare and aggressive neoplasm of unknown tissue origin, characterized by strong metastatic potential and poor prognosis. The present case of a 64-year-old male patient with pain and swelling in his right shoulder and progressive loss of movement demonstrates an uncommon location for the neoplasm. Magnetic resonance proton-density fat-suppressed turbo spin-echo sequences show a heterogeneous mass in the right shoulder. The lack of homogeneity in the signal has been described in medical literature as the "triple sign" and is represented by low, intermediate, and high signal intensity areas through the neoplasm. Visible serpentine vessels spread through the tumor. There was a visible metastatic disease in the regional lymph nodes and metastatic foci in the adjacent bones. Pathological analysis of the tumor confirmed the diagnosis of biphasic synovial sarcoma. An oncological committee advised chemotherapy and radiotherapy. More prominent magnetic resonance imaging findings in synovial sarcoma that may facilitate the diagnostic process are the inhomogeneity and "triple sign" in proton density and T2 sequences, multilobulated tumors, septa, irregular borders, serpentine vascular channels, engagement of the adjacent bones and bone marrow, and involvement of the joint synovia.

Pediatric whole-body magnetic resonance imaging: comparison of STIR and T2 Dixon sequences in the detection and grading of high signal bone marrow changes

ObjectivesTo compare short time inversion recovery (STIR) and T2 Dixon in the detection and grading of high signal intensity areas in bone marrow on whole-body MRI in healthy children.MethodsProspective study, including whole-body 1.5-T MRIs from 77 healthy children. Two experienced radiologists in consensus identified and graded areas of high bone marrow signal on STIR and T2-weighted (T2W) turbo spin echo (TSE) Dixon images (presence, extension) in two different sessions at an interval of at least 3 weeks. In a third session, a third observer joined the two readers for an additional consensus reading with all sequences available (substitute gold standard).ResultsFour hundred ninety of 545 (89.9%) high signal areas were visible on both sequences, while 27 (5.0%) were visible on STIR only and 28 (5.1%) on T2W Dixon only. Twenty-four of 27 (89%) lesions seen on STIR only, and 25/28 (89%) seen on T2W Dixon only, were graded as mildly increased signal intensity. The proportion of true positive high signal lesions was higher for the T2W Dixon images as compared to STIR (74.2% vs. 68.2%) (p = 0.029), while the proportion of false negatives was lower (25.9% vs. 31.7% (p = 0.035) for T2W Dixon and STIR, respectively). There was a moderate agreement between the T2W Dixon and STIR-based extension scores on a 0–4 scale, with a kappa of 0.45 (95% CI = 0.34–0.56).ConclusionsMost high signal bone marrow changes identified on a 1.5-T whole-body MRI were seen on both STIR and water-only T2W Dixon, underscoring the importance of using identical protocols when following bone-marrow signal changes over time.Key Points• Whole-body MRI is increasingly being used to diagnose and monitor diseases in children, such as chronic non-bacterial osteomyelitis, malignant/metastatic disease, and histiocytosis.• Standardized and validated imaging protocols, as well as reference standards by age for the growing skeleton are lacking.• Prospective single-center study showed that 90% of high signal bone marrow areas identified on a 1.5-T whole-body MRI in healthy children is seen on both STIR and water-only T2W Dixon, while 5% is seen on STIR only and 5% on T2W Dixon only.

A Case of Sinonasal Low-Grade Nonintestinal Adenocarcinoma That Was Difficult to Diagnose Preoperatively

AbstractWe report a case of sinonasal low-grade, nonintestinal adenocarcinoma (LG non-ITAC). The patient, a 56-year-old woman, was referred to our university hospital for a left nasal tumor with nasal obstruction, epistaxis, and nasal discharge. Nasal endoscopy revealed a nasal polypoid tumor with a smooth margin occupying the left nasal cavity. The sinonasal tumor was diagnosed as an exophytic papilloma by histopathology. Sinonasal contrast computed tomography (CT) confirmed homogeneous opacification of the left frontal, maxillary, and ethmoidal sinuses. There was no evidence of a potential bone defect. T2-weighted magnetic resonance imaging (MRI) showed a relatively uniform high signal intensity area in the left maxillary and frontal sinuses. An area of high signal intensity was also found in a part of the left ethmoid sinus. Left transnasal endoscopic ethmoidectomy was performed under general anesthesia. The tumor in the nasal cavity was prone to bleeding. We defined the site of tumor attachment as the suprabullar cell. The anterior ethmoidal artery was exposed, and the tumor was carefully dissected and removed. Based on the findings of these radiological and histological examinations, the sinonasal tumor was diagnosed as a LG non-ITAC. Sinonasal non-ITAC is an adenocarcinoma without the histopathological characteristics of salivary or intestinal-type adenocarcinoma. Non-ITAC is additionally classified into the high-grade and LG types. LG non-ITAC is very uncommon. Thus far, there is only one published report in the literature on the clinical and therapeutic characteristics of LG non-ITAC in Japan. Non-ITAC has a good prognosis, with a low risk of metastasis. Therefore, it is imperative to suspect and distinguish non-ITAC from other sinonasal tumors with similar symptoms preoperatively.

New Imaging Features of Multinodular and Vacuolating Neuronal Tumor Revealed by Alcohol and Illicit Drugs Consumption.

It has been almost a decade since the multinodular and vacuolating neuronal tumor (MVNT) was first described. In 2021, WHO classified it as a defined entity, and it is considered one of the glioneuronal and neuronal tumors. Due to its similarities with dysembryoplastic neuroepithelial tumors (DNET), some authors consider it a variant of these, ranking in the category of malformations, but genetic alterations favor a neoplastic origin. We present a 29-year-old male with a generalized onset tonic-clonic seizure after a nightclub party. Imaging studies revealed a right temporal multinodular and vacuolating neuronal tumor confirmed by biopsy. It is considered a nonaggressive, "leave me alone" brain lesion, which does not require biopsy because of well-defined MRI characteristics. Surgery is indicated only in symptomatic cases. We consider that this lesion was revealed by his seizure, most probably provoked (with normal video EEG recording) by the consumption of a lot of alcohol, illicit drugs, and sleep loss after a club party. We recommended close monitoring, but our patient preferred the surgery. Our case added more imaging details corroborated with the histopathology features of MVNT. FLAIR images revealed hypointense nodules surrounded by hyperintense peripheral rings and areas of high signal intensity between the nodules, which correspond to the histopathological architecture. To our knowledge, this is the first case of MVNT with diffusion tensor imaging and fiber tractography imaging studies.

Assessment of Age-Related Changes in Normal Clivus Bone Marrow Using Clivus-to-Corpus Callosum Signal Intensity Ratio on Magnetic Resonance Imaging

Objective: To assess whether the signal intensity ratio of the clivus to corpus callosum (clivus/CC) depends on age. Materials and Methods: A retrospective study of 244 subjects investigated the magnetic resonance imaging (MRI) appearance of the clivus on T1-weighted sagittal images. Both qualitative and quantitative assessments of MRIs were evaluated. In qualitative assessment, signal intensity patterns of clivus were graded from I to III, according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, the authors performed multivariable Gaussian regression analysis to assess the association of age categorized by decades and the signal intensity ratio of clivus/CC and clivus to cerebrospinal fluid (clivus/CSF). Results: Grade I clivus was found in about 40% of the age 1 to 9, whereas Grade III clivus was more frequent at more than 15% in the age over 50. There were statistically different in the mean values of clivus/CSF and clivus/CC signal intensity ratios by grades. The mean values of clivus/CSF and clivus/CC signal intensity ratios were increased by ages in both genders, but slightly higher in males. In unadjusted analyses, the differences in mean values of clivus/CC signal intensity ratio were larger by increasing age. After adjustment for gender, the difference in mean values remained the same. Conclusion: There was an age-related pattern of clivus bone marrow intensity. Since the use of CC as a new landmark showed a similar pattern as of pons, the ratio of clivus/CC signal intensity may be used as an alternative measurement in brain MRI. Keywords: Clivus; Bone marrow; Magnetic resonance imaging (MRI); Corpus callosum (CC)

VP.46 Dermatomyositis-specific autoantibodies and muscle MRI findings

To date, 5 dermatomyositis specific autoantibodies (DMSAs) have been identified. Recent studies have revealed that each DM subtype according to the positive DMSA has clinical and pathological characteristic features, which naturally raises a question whether each DM subtype has unique features also on muscle MRI. We studied muscle MRI of 125 patients who had one of the 5 DMSAs and were pathologically diagnosed with DM by sarcoplasmic MxA expression at our center from January 2009 to November 2021. A total of proximal 12 leg and 8 arm muscles were evaluated in the axial plane, in addition to fascia and subcutaneous fat (SF). For skeletal muscle, the intensity (faint or strong), distribution (diffuse, patchy, or peripheral), percent area of affected (none, below 50%, more than 50%), and the texture (honeycomb pattern, homogeneous, or heterogeneous) of high signal intensity (HSI) within each muscle were evaluated. We graded the scores 0-3 according to the percent area of HSI in fascia and the scores 0-2 according to the HSI in SF. Among 125 patients, 79 were women, 32 were children (< 18years), and the median age were 54 years. Of these patients, 42 had anti-TIF1-γ, 16 anti-Mi-2, 16 anti-MDA5, 44 anti-NXP2, and 7 anti-SAE antibodies, respectively. Anti-TIF1-γ DM was associated with peripheral distribution of HSI (97.6% vs non- TIF1-γ DM 77.1%; p < 0.01). Anti-NXP2 DM was associated with diffuse distribution of HSI (97.7% vs 76.5%; p < 0.01) and high fascia score (p < 0.05). Anti-MDA5 DM was reversely associated with diffuse distribution of HSI (31.3% vs 91.7%; p < 0.001) and honeycomb pattern (62.5% vs 99.1%; p < 0.001), while it tended to have patchy distribution of HSI (56.3% vs 31.2%; p = 0.057). All DM patients had at least one HSI area in fascia. Each DM subtype according to positive DMSA seems to have characteristic MRI features, except for anti-SAE DM whose sample number was too small in this study. Fascial edema is common among DM patients.

Quantitative analysis of mean apparent propagator-magnetic resonance imaging for distinguishing glioblastoma from solitary brain metastasis

PurposeDistinguishing glioblastoma (GBM) and solitary brain metastasis (SBM) is vital for determining the optimal treatment. GBM and SBM present similar imaging characteristics on conventional magnetic resonance imaging (MRI). The aim of this study was to evaluate the efficacy of quantitative analysis of mean apparent propagator (MAP)-MRI for distinguishing GBM and SBM. MethodEighty-nine patients were enrolled. Regions of interest (ROIs), including the enhancing area (EA), peritumoural high signal intensity area (PHA), and maximum abnormal signal area (MASA), were manually delineated. The following MAP parameters for each region were measured: mean square displacement (MSD), non-Gaussianity (NG), NG axial (NGAx), NG vertical, Q-space inverse variance, return to origin probability (RTOP), return to axis probability (RTAP), and return to plane probability (RTPP). Normalised MAP values from each region were compared between the GBM and SBM groups, and their diagnostic efficiency was assessed. Multivariate logistic regression analysis was used to create the most accurate model. ResultsCompared with the SBM group, the MSD was significantly lower in the GBM group, whereas the RTAP, RTOP, and RTPP were significantly higher in each region, except for RTAPPHA (all P < 0.05). RTPPPHA, MSDEA, and RTPPMASA showed the most significant differences (all P < 0.01). The best logistic regression model combined RTPPPHA, MSDEA, and NGAxMASA (area under the curve, 0.840). ConclusionsQuantitative analysis of MAP-MRI is useful for distinguishing GBM from SBM. Multivariate analysis combined with multiple ROIs can improve diagnostic performance.

Age-Related Changes in Signal Intensity Ratio of Normal Clivus Bone Marrow on Magnetic Resonance Imaging

Objective: To evaluate the association between the signal intensity ratio of clivus bone displayed on magnetic resonance (MR) imaging and ages.Materials and Methods: A retrospective cohort study of 268 patients underwent brain MR imaging during January 2015 to October 2019. We qualitatively and quantitatively assessed bone marrow signal intensity of clivus bone that were performed on T1-weighted sagittal images. In qualitative assessment, the signal intensities of clivus were visually graded from Grade I to III according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, we evaluated the association between the signal intensity ratio of clivus to pons and age categorized by decades in multivariable Gaussian regression analysis.Results: Of 268 patients, the ratio of males to females is 1:1. Grade I clivus was found about 35% of the age 1-9 years, whereas Grade 3 clivus was more frequent (more than 13%) in the ages over 30 years. There were statistically different in the mean values of clivus/CSF and clivus/pons signal intensity ratios by grades. The mean values of clivus/CSF and clivus/pons signal intensity ratios were increased by ages in both sexes, but slightly higher in males. In regression analysis after adjustment for sex, the differences in mean values of clivus/pons signal intensity ratios were larger by increasing age, using the age 1-9 as a reference group.Conclusion: The present study confirms that signal intensity ratios of clivus to pons on T1-weighted sagittal MR images is increased with ages.

Bimodal Interventional Instrument Markers for Magnetic Particle Imaging and Magnetic Resonance Imaging-A Proof-of-Concept Study.

The purpose of this work was to develop instrument markers that are visible in both magnetic particle imaging (MPI) and magnetic resonance imaging (MRI). The instrument markers were based on two different magnetic nanoparticle types (synthesized in-house KLB and commercial Bayoxide E8706). Coatings containing one of both particle types were fabricated and measured with a magnetic particle spectrometer (MPS) to estimate their MPI performance. Coatings based on both particle types were then applied on a segment of a nonmetallic guidewire. Imaging experiments were conducted using a commercial, preclinical MPI scanner and a preclinical 1 tesla MRI system. MPI image reconstruction was performed based on system matrices measured with dried KLB and Bayoxide E8706 coatings. The bimodal markers were clearly visible in both methods. They caused circular signal voids in MRI and areas of high signal intensity in MPI. Both the signal voids as well as the areas of high signal intensity were larger than the real marker size. Images that were reconstructed with a Bayoxide E8706 system matrix did not show sufficient MPI signal. Instrument markers with bimodal visibility are essential for the perspective of monitoring cardiovascular interventions with MPI/MRI hybrid systems.

Whole body magnetic resonance imaging in healthy children and adolescents: Bone marrow appearances of the appendicular skeleton

ObjectiveTo describe the appearances of bone marrow in the appendicular skeleton on fat-suppressed T2-weighted sequences as assessed by whole-body MRI in healthy and asymptomatic children and adolescents. Material and methodsFollowing ethical approval, we assessed the bone marrow of the extremities on water-only Dixon T2-weighted images as part of a whole-body MRI in 196 healthy and asymptomatic children aged 5–19 years. Based on a newly devised and validated scoring system, we graded intensity (0–2 scale) and extension (1–4 scale) of focal high signal bone marrow areas, and divided them into minor or major findings, based on intensity and extension, reflecting their potential conspicuousness in a clinical setting. ResultsIn the upper extremity, we registered 366 areas with increased signal whereof 79 were major findings. In the lower extremities there were 675 areas of increased signal of which 340 were major findings. Hundred-and-fifteen (58.79%) individuals had at least one major finding, mainly located in the hand and proximal humerus, and the feet and knees. We found no differences according to gender, reported hours of sports activity, handedness, or age group, except for more minor findings in the upper extremities amongst 15–18-year-olds as compared to those aged 5–8 years. ConclusionFocal areas of high signal intensity on whole-body MRI, T2-weighted fat suppressed images that, in a clinical setting could cause concern, were seen in more than half of healthy, asymptomatic children and adolescents. Awareness of this is important when interpreting whole-body MRI in this age group, particularly in the assessment of clinically silent lesions.

Whole-body MRI in children aged 6–18 years. Reliability of identifying and grading high signal intensity changes within bone marrow

BackgroundWhole-body magnetic resonance imaging (MRI) is increasingly being used in children, however, to date there are no studies addressing the reliability of the findings.ObjectiveTo examine intra- and interobserver reliability of a scoring system for assessment of high signal areas within the bone marrow, as visualized on T2-weighted, fat-saturated images.Materials and methodsNinety-six whole-body MRIs (1.5 T) in 78 healthy volunteers (mean age: 11.5 years) and 18 children with chronic nonbacterial osteomyelitis (mean age: 12.4 years) were included. Coronal water-only Dixon T2-weighted images were used to score the left lower extremity/pelvis for high signal intensity areas, intensity (0–2 scale), extension (0–4 scale) and shape and contour in a blinded fashion by two pairs of radiologists.ResultsFor the pelvis, grading of bone marrow signal showed moderate to good intra- and interobserver agreement with kappa values of 0.51–0.94 and 0.41–0.87, respectively. Corresponding figures for the femur were 0.61–0.68 within and 0.32–0.61 between observers, and for the tibia 0.60–0.72 and 0.51–0.73. Agreement for assessing extension was moderate to good both within and between observers for the pelvis (k = 0.52–0.85 and 0.35–0.80), for the femur (0.52–0.67 and 0.51–0.60) and for the tibia (k = 0.59–0.69 and 0.47–0.63) except for the femur metaphysis/diaphysis, with interobserver kappa values of 0.29–0.30. Scoring of shape was moderate to good within observers, but in general poorer between observers, with kappa values of 0.40–0.73 and 0.18–0.69, respectively. For contour, the corresponding figures were 0.35–0.62 and 0.09–0.54, respectively.ConclusionMRI grading of intensity and extension of high signal intensity areas within the bone marrow of pelvis and lower limb performs well and thus can be used interchangeably by different observers, while assessment of shape and contour is reliable for the same observer but is less reliable between observers. This should be considered when performing clinical trials.

Multiple intestinal lymphangiomas with episodic hemorrhage requiring partial laparoscopic resection: a case report

BackgroundLymphangioma is a non-epithelial tumor marked by aggregates of abnormally dilated lymphatics. Mesenteric occurrences account for < 1% of all cases, and < 0.05% involve the gastrointestinal tract. Most are confined to children, rarely affecting adults.Case presentationHerein, we describe an elderly Japanese woman with anemia, hypoalbuminemia, and episodic bleeding due to multiple intestinal lymphangiomas. Abdominal computed tomography revealed multiple low-density defects of mesentery, with areas of intermediate (T1 images) or high (T2 images) signal intensity similarly dispersed in magnetic resonance scanning sequences. Single-balloon enteroscopy was undertaken, enabling identification and tattooing of a small intestinal bleeding source. Laparoscopy-assisted resection at this site served to control related hemorrhage, removing a histologically confirmed hemolymphangioma. Having recovered uneventfully, the patient remained stable 2 months postoperatively.ConclusionsAlthough rare in adults, mesenteric or gastrointestinal lymphangiomas must be considered in a setting of anemia and hypoalbuminemia. Complete resection is advantageous to improve patient symptoms, but limited resection of multiple lesions may be equally effective.

Application of ultra-short echo time-T2* component analysis technology in monitoring morphological and biochemical changes of achilles tendon in amateur marathon athletes

Objective: To explore the value of ultra-short echo time (UTE)-T2* component analysis techniques in dynamic monitoring the morphological and biochemical changes in amateur marathon athletes' achilles tendon before and after the marathon. Methods: Twenty-nine amateur marathon runners were recruited between October 2020 and March 2021 in Zhuhai City, Guangdong Province, including 25 males and 4 females, aged from 24 to 50 (40±6) years old. All volunteers underwent bilateral achilles tendon MRI examination 1 week before the marathon, 48 hours after the race, and 1 month after the race. The shape and signal of the achilles tendon were evaluated by routine T1-weighted, proton density weighted with fat saturation sequence and different echo time (TE) UTE sequence, and the changes of achilles tendon after running was quantitatively analyzed by UTE-T2* sequence. The values of single-component analysis (T2*M), short T2* components (T2*S), and long T2* components (T2*L) and Fraction values were obtained using UTE-T2* sequence. The value of the whole achilles tendon was measured on the sagittal images of achilles tendon, and the Achilles tendon was equally divided into three subregions [muscle-tendon junction (MTJ), middle (MID), and insertion (INS)]. The region of interest was delineated by two radiologists independently. The intra-group correlation coefficient (ICC) was used to evaluate the consistency of the data measured by two radiologists. Nonparametric Friedman M test was used to compare the differences of T2*M, T2*S, T2*L and Fraction values in different time points and different subregions. Wilcoxon rank-sum test was used to compare the difference between 48 h post-race and pre-race T2*S values (ΔT2*S) of different distance, different running posture, different pace and different amount of training, in which ΔT2*S equals the T2*S value of 48 h post-race minus the T2*S value of pre-race. Results: On the sequence of short TE (TE≤0.6 ms), achilles tendinopathy can manifest as scattered punctate hypointensity in areas of high signal intensity. The two radiologists showed a good consistency in measuring the T2*M, T2*S, T2*L and Fraction values of the achilles tendon, and the ICC values ​​were 0.96, 0.94, 0.83 and 0.94, respectively. The T2*s values was significantly higher in the whole Achilles tendon, MTJ and MID segment at 48 h post-exercise compared to pre-exercise, and decreased after 1 month of exercise, [0.49 (0.45, 0.59) vs 0.54 (0.49, 0.59) vs 0.53 (0.49, 0.57), 0.48 (0.44, 0.54) vs 0.53 (0.47, 0.58) vs 0.50 (0.46, 0.57), 0.48 (0.43, 0.58) vs 0.54 (0.47, 0.59) vs 0.52 (0.46, 0.57); respectively, all P<0.05]. The changes in T2*M, T2*L and Fraction values are not statistically significant (all P>0.05). In different running gestures, the ΔT2*S of achilles tendon who using the postures of front-middle feet is higher than that using the postures of back feet (0.03(-0.05, 0.07) vs -0.03(-0.17, 0.11), P=0.001). Conclusion: The Bi-component analysis of UTE-T2* technology is superior to single component analysis in monitoring the dynamic changes of achilles tendon before and after exercise, and T2*S is a more sensitive sequence to evaluate the subtle changes in the chemical composition of achilles tendon.

The potential role of diffusion weighted imaging in the diagnosis of early carotid and vertebral artery dissection

PurposeTo investigate the role of the diffusion weighted imaging (DWI) in the acute dissection of internal carotid artery (ICA) and vertebral artery (VA) and assessing the length of intramural hematoma (IMH), caused by dissection.MethodsWe analyzed 28 patients presenting with a dissection of the ICA and/or VA with respect to the presence of high signal intensity areas on DWI suggestive of dissection and 20 control subjects without arterial dissection, some with and some without atherosclerotic lesions. ICA or VA dissection was defined by clinical and imaging, computed tomography angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA) findings. The length of DWI hyperintensity was compared to length of the occlusion or stenosis on the angiographic examination.ResultsIn 28 patients, 30 dissected arteries were analyzed. Time intervals from the onset of the first clinical symptoms to the radiological evaluation ranged from 1.5 h to 42 days. In 28 (93%) of the dissections, a high signal intensity of the affected artery was present on DWI. The measurement of the dissection length on DWI compared to DSA showed a mean deviation of 2.7 mm and a standard deviation of 3.7 mm.ConclusionDWI is a highly sensitive and valuable pulse sequence for the detection of dissected cervical arteries even in the first hours after symptom onset. In contrast to CTA and MRA, DWI can be a potential tool for a reliable measurement of the dissection length.