MR Techniques Research Articles

Utility of silent magnetic resonance angiography in the evaluation and characterisation of intracranial dural arteriovenous fistula

To evaluate the utility of silent magnetic resonance angiography (MRA) in the diagnosis, characterisation, and therapeutic planning of intracranial dural arteriovenous fistula (DAVF). Twenty consecutive patients with DAVF were enrolled prospectively and were evaluated using silent MRA and digital subtraction angiography (DSA) as a part of routine work-up. The diagnosis and location of fistula, Borden and Cognard classification, entire arterial feeders, and venous drainage were analysed. A therapeutic strategy was formulated, and the accessible route and vessel were predicted, which was confirmed on endovascular treatment. Silent MRA was 100% sensitive and accurate for location and classification of fistulas. Silent MRA showed a sensitivity of 82% and 76.5% for entire arterial feeders and draining veins, which improved to a sensitivity of 90% and 94% when prominent feeders and immediate venous drainage was considered. Among the missed veins, thrombosed sinus, slow sinus flow, small calibre, reduced image quality were the causes. The therapeutic decision matched with DSA in all cases and silent MRA accurately identified the potential accessible feeder in 94% cases. Silent MRA is a promising MR technique that can provide both diagnostic and therapeutic information similar to that obtained from DSA.

Assessment of blood supply of the external carotid artery in moyamoya disease using super-selective pseudo-continuous arterial spin labeling technique.

To evaluate the diagnostic accuracy of super-selective pseudo-continuous arterial spin labeling (ss-pCASL) at depicting external carotid artery (ECA) perfusion territory in moyamoya disease (MMD). In total, 103 patients with MMD who underwent both ss-pCASL and digital subtraction angiography (DSA, the reference standard) were included. There were 3, 184, and 19 normal, preoperative, and postoperative MMD hemispheres, respectively. The ss-pCASL results were interpreted by two different visual inspection criteria: presence or absence and definite or indefinite ECA perfusion territory. The performance of ss-pCASL at depiction of ECA perfusion territory was compared to that of DSA. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. The κ statistic was used to assess intermodality and inter-reader agreement. When interpreted as presence or absence, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ss-pCASL for depicting ECA perfusion territory were 78.3 %, 79.6 %, 92.5 %, 53.4 %, and 78.6 %, respectively, and the intermodality and inter-reader agreement were κ = 0.49 (CI: 0.43 - 0.55, p < 0.01) and 0.71 (CI: 0.66 - 0.76, p < 0.01), respectively. When interpreted as definite or indefinite, the respective values were 61.1%, 100%, 100%, 44.5%, 70.4%, κ = 0.42 (CI: 0.37 - 0.47, p < 0.01), and 0.90 (CI: 0.87 - 0.93, p < 0.01). ss-pCASL has substantial sensitivity and specificity compared with DSA for depicting the presence versus absence of ECA perfusion territory in MMD. As a noninvasive method in which no ionradiation or contrast medium is needed, ss-pCASL may potentially reduce the need for repeated DSA examination. • Super-selective pseudo-continuous arterial spin labeling (ss-pCASL) is a noninvasive vessel-selective MR technique to demonstrate perfusion territory of a single cerebral artery. • Compared with digital subtraction angiography, ss-pCASL has substantial sensitivity and specificity for depicting the perfusion territory of the external carotid artery in brain parenchyma in moyamoya disease. • ss-pCASL may potentially reduce the need for repeated DSA examination.

Whole-brain 3D MR fingerprinting brain imaging: clinical validation and feasibility to patients with meningioma

PurposeMR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma.Materials and methodsA whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman’s ANOVA test.ResultsMR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001)ConclusionsPhantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.

Magnetic resonance angiography and perfusion mapping by arterial spin labeling using Fourier transform-based velocity-selective pulse trains: Examination on a commercial perfusion phantom.

Purpose:Benchmarking of flow and perfusion MR techniques on standardized phantoms can facilitate the use of advanced angiography and perfusion-mapping techniques across multiple sites, field strength, and vendors. Here, MRA and perfusion mapping by arterial spin labeling (ASL) using Fourier transform (FT)–based velocity-selective saturation and inversion pulse trains were evaluated on a commercial perfusion phantom.Methods:The FT velocity-selective saturation–based MRA and FT velocity-selective inversion–based ASL perfusion imaging were compared with time-of-flight and pseudo-continuous ASL at 3 T on the perfusion phantom at two controlled flow rates, 175 mL/min and 350 mL/min. Velocity-selective MRA (VSMRA) and velocity-selective ASL (VSASL) were each performed with three velocity-encoding directions: foot–head, left–right, and oblique 45°. The contrast-to-noise ratio for MRA scans and perfusion-weighted signal, as well as labeling efficiency for ASL methods, were quantified.Results:On this phantom with feeding tubes having only vertical and transverse flow directions, VSMRA and VSASL exhibited the dependence of velocity-encoding directions. The foot–head-encoded VSMRA and VSASL generated similar signal contrasts as time of flight and pseudo-continuous ASL for the two flow rates, respectively. The oblique 45°–encoded VSMRA yielded more uniform contrast-to-noise ratio across slices than foot–head and left–right-encoded VSMRA scans. The oblique 45°–encoded VSASL elevated labeling efficiency from 0.22–0.68 to 0.82–0.90 through more uniform labeling of the entire feeding tubes.Conclusion:Both FT velocity-selective saturation–based VSMRA and FT velocity-selective inversion–based VSASL were characterized on a commercial perfusion phantom. Careful selection of velocity-encoding directions along the major vessels is recommended for their applications in various organs.

MR Image Changes of Normal-Appearing Brain Tissue after Radiotherapy.

Simple SummaryRadiotherapy is one of the most important treatment options against cancer. Irradiation of cancerous tissue either directly destroys the cancer cells or damages them such that they cannot reproduce. One side-effect of radiotherapy is that tumor-surrounding normal tissue is inevitably also irradiated, albeit at a lower dose. The resulting long-term damage can significantly affect cognitive performance and quality of life. Many studies investigated the effect of irradiation on normal-appearing brain tissues and some of these correlated imaging findings with functional outcome. This article provides an overview of the examination of radiation-induced injuries using conventional and enhanced MRI methods and summarizes conclusions about the underlying tissue changes. Radiation-induced morphologic, microstructural, vascular, and metabolic tissue changes have been observed, in which the effect of irradiation was evident in terms of decreased perfusion and neuronal health as well as increased diffusion and atrophy.Radiotherapy is part of the standard treatment of most primary brain tumors. Large clinical target volumes and physical characteristics of photon beams inevitably lead to irradiation of surrounding normal brain tissue. This can cause radiation-induced brain injury. In particular, late brain injury, such as cognitive dysfunction, is often irreversible and progressive over time, resulting in a significant reduction in quality of life. Since 50% of patients have survival times greater than six months, radiation-induced side effects become more relevant and need to be balanced against radiation treatment given with curative intent. To develop adequate treatment and prevention strategies, the underlying cause of radiation-induced side-effects needs to be understood. This paper provides an overview of radiation-induced changes observed in normal-appearing brains measured with conventional and advanced MRI techniques and summarizes the current findings and conclusions. Brain atrophy was observed with anatomical MRI. Changes in tissue microstructure were seen on diffusion imaging. Vascular changes were examined with perfusion-weighted imaging and susceptibility-weighted imaging. MR spectroscopy revealed decreasing N-acetyl aspartate, indicating decreased neuronal health or neuronal loss. Based on these findings, multicenter prospective studies incorporating advanced MR techniques as well as neurocognitive function tests should be designed in order to gain more evidence on radiation-induced sequelae.

Evaluation of Neonatal Acute Metabolic Crisis in Maple Syrup Urine Disease with MR Diffusion and MR Spectroscopy: Case Series and Review of the Literature

AbstractMagnetic resonance imaging (MRI) findings of acute metabolic crisis in maple syrup urine disease (MSUD) in neonates were reviewed. This case cohort study included six MSUD neonates imaged during acute metabolic decompensation. Specific diffusion imaging and proton spectroscopic findings were reviewed. All patients revealed extensive intramyelinic cytotoxic edema typically involving myelinated white matter structures. Brainstem, cerebellar white matter and peduncles, midbrain, posterior limbs of internal capsules, central portions of periventricular, and perirolandic white matter regions showed typical MSUD edema. Gray matter structures such as dentate nucleus and thalamus were involved in all patients. Involvement of other deep nuclei was also noted in a few patients. None of the patients showed involvement of the superficial cortex. Reduction in N-acetyl aspartate, a prominent lactate peak, and a peak representing methyl groups of amino acids were characteristic findings seen on intermediate short echo time MR spectroscopy. Our case series outlines the importance of diffusion and spectroscopy MR techniques in the diagnosis of acute neonatal MSUD metabolic crisis.

Role of ABER Positioning in Evaluation of Anteroinferior Labroligamentous Lesions in Shoulder MR Arthrograms

Background: MR arthrography in the abduction and external rotation (ABER) position has been demonstrated to enhance the diagnostic ratio of anterior labro-ligamentous complex tears. Meanwhile, the diagnostic and discriminatory rates of MR arthrography in this position in various types of the antero-inferior labro-ligamentous lesions have not been completely discovered. Aim: This study aimed to perform comparison between ABER MR and the conventional MR arthrography considering the diagnostic rate and discriminatory precision of various anteroinferior labro-ligamentous lesions. Methods: We studied 38 patients who suffered from shoulder conditions and evaluated the results of both conventional MR and ABER MR arthrography. An antero-inferior labro-ligamentous lesion was diagnosed with the detection of absence, fray, detachment, displacement of the antero-inferior labrum or detection of the contrast material inside the labrum, or avulsion, rupture of the inferior glenohumeral ligament at the humeral or labral attachment. All study subjects have undergone shoulder arthroscopy after MR technique. Results: ABER MR arthrography was associated with significant increased accuracy and diagnostic sensitivity than that of conventional MR regarding the diagnostic rate of various types of the antero-inferior labro-ligamentous lesions (p < 0.05). Conclusion: Based on our results, ABER MR arthrography would add more value to the diagnosis if the conventional MR were doubtful in suspected antero-inferior labro-ligamentous complex injuries.

Application of 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm

ObjectivesTo assess 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm. Materials and methodsBetween Oct 2018 and May 2019, we enrolled 25 patients with intracranial aneurysm who underwent stent-assisted coil embolization. All patients were followed up for 6 to10 months after endovascular treatment (EVT) using 3D-TOF MRA, 3D T1-SPACE and DSA to evaluate aneurysm occlusion and parent artery patency. ResultsWith regards to aneurysm occlusion, the specificity of 3D-TOF MRA was 86.9% (20/23) and the accuracy was 84% (21/25). There was no statistical significance (P ​= ​0.409) compared with the DSA. The parent artery by 3D-TOF MRA showed that there were 14 patients with grade 3, 8 patients with grade 2 and 3 patients with grade 1. However, 3D T1-SPACE showed that all 25 patients were grade 4, and were clearly displayed without metal artifacts. The comparison of the two MR techniques demonstrated that 3D T1-SPACE was superior to 3D-TOF MRA in the evaluation of parent artery (P<0.001). Conclusions3D T1-SPACE sequence provides better image quality and higher accuracy for evaluating stented parent arteries compared to TOF-MRA. This study also shows that 3D-TOF MRA has a merit to evaluate aneurysm occlusion. The combination of these two modalities can be used as an optional follow-up evaluation after EVT of intracranial aneurysms.

Adrenal incidentalomas: imaging challenges\u2014role of MDCT scan versus MRI in evaluating adrenal incidentalomas

BackgroundThe term adrenal incidentaloma (AI), by definition, is an adrenal mass that is unexpectedly detected through an imaging procedure performed for reasons unrelated to adrenal dysfunction or suspected dysfunction. Despite their frequent appearance, the challenge remains in recognizing and treating the small percentage of AI that poses a significant risk, either because of their hormonal activity or because of their malignant histology. The aim of this study is to study the role of MRI, specifically chemical shift imaging (CSI), against various MDCT scans (non-enhanced, enhanced, and delayed) in the characterization of incidentally discovered adrenal masses to offer a way for the patients to avoid unnecessary time and money-wasting imaging modalities used to reach a diagnosis of their incidentally discovered adrenal lesions. We examined a total number of 20 patients with total of 22 adrenal lesions. The mean age was 51.1 ± 15.27.ResultsIn our study, we found that among CT parameters, APW and RPW showed the highest sensitivity and specificity for detection of lipid-rich adenomas. CSI has also proven to be the best MR technique. However, there is no statistically significant difference in the diagnostic capability of CSI versus the CT washout technique. Both modalities could be conducted, according to specific patient preferences and/or limitations, with comparable highly accurate outcomes.ConclusionThis study demonstrates that a similar diagnostic outcome is obtained from contrast-enhanced CT (CECT) and MRI with CSI of adrenal lesions.

Quantification of intracranial arterial stenotic degree evaluated by high-resolution vessel wall imaging and time-of-flight MR angiography: reproducibility, and diagnostic agreement with DSA.

The purpose of this study was to compare the reproducibility and diagnostic agreement of high-resolution vessel wall imaging (HR-VWI) and time-of-flight magnetic resonance angiography (TOF-MRA) with digital subtraction angiography (DSA) to evaluate intracranial arterial stenosis. We retrospectively enrolled patients who underwent HR-VWI and TOF-MRA with suspected intracranial artery disease and had DSA results from our institutional imaging database. Two neuroradiologists separately and independently evaluated anonymous image data for the stenotic lesions. DSA was analyzed by two neurointerventionalists and it served as a standard criterion. The reproducibility of these two MR techniques was determined by the intraclass correlation coefficients (ICCs). The diagnostic agreement to DSA was assessed by the concordance correlation coefficients (CCCs). A total of 246 lesions from 106 individuals were analyzed for stenotic degrees. The total intra-observer and inter-observer reproducibility of HR-VWI was excellent for identifying stenosis and better than of TOF-MRA. The overall concordance of HR-VWI with DSA was excellent with CCC = 0.932, whereas TOF-MRA was 0.694. In addition, HR-VWI could provide additional vessel wall information. HR-VWI has more advantages over TOF-MRA, such as better reproducibilities and diagnostic agreements with DSA to analyze intracranial arterial stenosis. It provides additional information that helps in clinical diagnosis and management. • High-resolution vessel wall imaging can assess intracranial arterial stenosis with a better reproducibility than TOF-MRA and has a higher diagnostic agreement with DSA. • High-resolution vessel wall imaging had a higher diagnostic agreement with DSA compared with TOF-MRA. • Apart from evaluating vascular stenosis, HR-VWI provided additional vessel wall information to help in clinical diagnosis.

Bosniak classification of cystic renal masses, version 2019: interpretation pitfalls and recommendations to avoid misclassification.

The purpose of this review is to describe the potential sources of variability or discrepancy in interpretation of cystic renal masses under the Bosniak v2019 classification system. Strategies to avoid these pitfalls and clinical examples of diagnostic approaches are also presented. Potential pitfalls in the application of Bosniak v2019 are divided into three categories: interpretative, technical, and mass related. An organized, comprehensive review of possible discrepancies in interpreting Bosniak v2019 cystic masses is presented with pictorial examples of difficult clinical cases and proposed solutions. The scheme provided can guide readers to consistent, precise application of the classification system. Radiologists should be aware of the possible sources of misinterpretation of cystic renal masses when applying Bosniak v2019. Knowing which features and types of cystic masses are prone to interpretive errors, in addition to the inherent trade-offs between the CT and MR techniques used to characterize them, can help radiologists avoid these pitfalls.

QSMART: Quantitative susceptibility mapping artifact reduction technique

Purpose: Quantitative susceptibility mapping (QSM) is a novel MR technique that allows mapping of tissue susceptibility values from MR phase images. QSM is an ill-conditioned inverse problem, and although several methods have been proposed in the field, in the presence of a wide range of susceptibility sources, streaking artifacts appear around high susceptibility regions and contaminate the whole QSM map. QSMART is a post-processing pipeline that uses two-stage parallel inversion to reduce the streaking artifacts and remove banding artifact at the cortical surface and around the vasculature. Method: Tissue and vein susceptibility values were separately estimated by generating a mask of vasculature driven from the magnitude data using a Frangi filter. Spatially dependent filtering was used for the background field removal step and the two susceptibility estimates were combined in the final QSM map. QSMART was compared to RESHARP/iLSQR and V-SHARP/iLSQR inversion in a numerical phantom, 7T in vivo single and multiple-orientation scans, 9.4T ex vivo mouse data, and 4.7T in vivo rat brain with induced focal ischemia. Results: Spatially dependent filtering showed better suppression of phase artifacts near cortex compared to RESHARP and V-SHARP, while preserving voxels located within regions of interest without brain edge erosion. QSMART showed successful reduction of streaking artifacts as well as improved contrast between different brain tissues compared to the QSM maps obtained by RESHARP/iLSQR and V-SHARP/iLSQR. Conclusion: QSMART can reduce QSM artifacts to enable more robust estimation of susceptibility values in vivo and ex vivo.

Value of diffusion tensor imaging and tractography in unilateral lumbar disc prolapse

BackgroundConventional MR imaging is not enough for evaluation of symptomatic foraminal stenosis, because there is high incidence of false-positive results in asymptomatic elderly patients. Conventional MR cannot quantitatively assess the severity of the nerve lesion. DTI is a non-invasive way to effectively trace the nerve fiber bundle and quantitatively evaluate the nerve injury. DTI with fiber tracking may describe abnormalities beyond the resolution of conventional MR techniques. The aim of this work was to compare between the mean values of diffusion parameters such as fractional anisotropy and apparent diffusion coefficient of the compressed lumbar spinal nerve roots and of the contralateral normal nerve roots. Correlate these parameters with the severity of neurological symptoms. This is a prospective study that was conducted on 50 patients with symptomatic unilateral posterolateral lumbar disc prolapse at a university hospital. They were investigated with diffusion tensor imaging with tractography on a 1.5-T MR. The changes in the mean fractional anisotropy and apparent diffusion coefficient values of the compressed nerves and the relationship between these changes and the severity of the neurological side effects using Japanese Orthopedic Association score and visual analogue scale were investigated.ResultsThe mean fractional anisotropy values were significantly lower (p ≤ 0.001), and mean apparent diffusion coefficient values were significantly higher (p ≤ 0.001) in compressed nerves than in contralateral intact nerves. There were strong correlations between the DTI parameters and the severity of the neurological symptoms as assessed using the Japanese Orthopedic Association score and the visual analogue scale.ConclusionIn patients with lumbar disc prolapse, radicular diffusion parameters are affected in the compressed roots in comparison to the healthy roots and this affection is correlated with the degree of prolapse and with the severity of neurological symptoms. DTI with fiber tracking provide clinically relevant information and describe abnormalities beyond the resolution of conventional MR techniques.

Tracking of Labelled Stem Cells Using Molecular MR Imaging in a Mouse Burn Model in Vivo as an Approach to Regenerative Medicine.

Therapies based on stem cell transplants offer significant potential in the field of regenerative medicine. Monitoring the fate of the transplanted stem cells in a timely manner is considered one of the main limitations for long-standing success of stem cell transplants. Imaging methods that visualize and track stem cells in vivo non-invasively in real time are helpful towards the development of successful cell transplantation techniques. Novel molecular imaging methods which are non-invasive particularly such as MRI have been of great recent interest. Hence, mouse models which are of clinical relevance have been studied by injecting contrast agents used for labelling cells such as super-paramagnetic iron-oxide (SPIO) nanoparticles for cellular imaging. The MR techniques which can be used to generate positive contrast images have been of much relevance recently for tracking of the labelled cells. Particularly when the off-resonance region in the vicinity of the labeled cells is selectively excited while suppressing the signals from the non-labeled regions by the method of spectral dephasing. Thus, tracking of magnetically labelled cells employing positive contrast in vivo MR imaging methods in a burn mouse model in a non-invasive way has been the scope of this study. The consequences have direct implications for monitoring labeled stem cells at some stage in wound healing. We suggest that our approach can be used in clinical trials in molecular and regenerative medicine.

The Emerging Role of Fast MR Techniques in Traumatic Brain Injury

The Emerging Role of Fast MR Techniques in Traumatic Brain Injury

Role of Double Inversion Recovery Sequence in Neuro-imaging on 3 Tesla MRI

Double Inversion Recovery (DIR) is a robust sequence designed to suppress fat and water signals using two 180° inversion pulses to produce prominent gray matter contrast with high spatial resolution. It has proven to be more sensitive in delineating white matter signal abnormalities than conventional MR techniques. In our study, the highest image contrast with lesion load was observed using DIR over FLAIR and T2 weighted imaging. DIR is evidently valuable for the detection of demyelinating lesions observed in multiple sclerosis (MS), malignancies, epileptogenic foci, and cortical anomalies. Hence this pictorial review is intended to assess the diagnostic efficacy of DIR modality in clinical Neuro-imaging.

Gadolinium-based contrast agents: What we learned from acute adverse events, nephrogenic systemic fibrosis and brain retention.

Radiologists have been administering gadolinium-based contrast agents (GBCA) in magnetic resonance imaging for several decades, so that there is abundant experience with these agents regarding allergic-like reactions, nephrogenic systemic fibrosis (NSF) and gadolinium retention in the brain. This review is based on a selective literature search and reflects the current state of research on acute adverse effects of GBCA, NSF and brain retention of gadolinium. Due to the frequent use of GBCA, data on adverse effects of these compounds are available in large collectives. Allergic-like reactions occurred rarely, whereas severe acute reactions were very rarely observed. Systemic changes in NSF also occur very rarely, although measures to avoid NSF resulted in a significantly reduced incidence of NSF. Due to gadolinium retention in the body after administration of linear MR contrast agents, only macrocyclic preparations are currently used with few exceptions. Clear clinical correlates of gadolinium retention in the brain could not be identified so far. Although the clinical added value of GBCA is undisputed, individual risks associated with the injection of GBCA should be identified and the use of non-contrast enhanced MR techniques should be considered. Alternative contrast agents such as iron oxide nanoparticles are not clinically approved, but are currently undergoing clinical trials. GBCA have a very good risk profile with a low rate of adverse effects or systemic manifestations such as NSF. Gadolinium retention in the brain can be minimized by the use of macrocyclic GBCA, although clear clinical correlates due to gadolinium retention in the brain following administration of linear GBCA could not be identified yet. · Acute adverse effects are predominantly mild/moderate, rarely severe reactions occur.. · International guidelines resulted in significant reduction of nephrogenic systemic fibrosis.. · Application of macrocyclic contrast agents minimizes gadolinium retention in the brain.. · Bäuerle T, Saake M, Uder M. Gadolinium-based contrast agents: What we learned from acute adverse events, nephrogenic systemic fibrosis and brain retention. Fortschr Röntgenstr 2021; 193: 1010 - 1018.

Additional value and new insights by four-dimensional flow magnetic resonance imaging in congenital heart disease: application in neonates and young children

Cardiovascular MRI has become an essential imaging modality in children with congenital heart disease (CHD) in the last 15–20 years. With use of appropriate sequences, it provides important information on cardiovascular anatomy, blood flow and function for initial diagnosis and post-surgical or -interventional monitoring in children. Although considered as more sophisticated and challenging than CT, in particular in neonates and infants, MRI is able to provide information on intra- and extracardiac haemodynamics, in contrast to CT. In recent years, four-dimensional (4-D) flow MRI has emerged as an additional MR technique for retrospective assessment and visualisation of blood flow within the heart and any vessel of interest within the acquired three-dimensional (3-D) volume. Its application in young children requires special adaptations for the smaller vessel size and faster heart rate compared to adolescents or adults. In this article, we provide an overview of 4-D flow MRI in various types of complex CHD in neonates and infants to demonstrate its potential indications and beneficial application for optimised individual cardiovascular assessment. We focus on its application in clinical routine cardiovascular workup and, in addition, show some examples with pathologies other than CHD to highlight that 4-D flow MRI yields new insights in disease understanding and therapy planning. We shortly review the essentials of 4-D flow data acquisition, pre- and post-processing techniques in neonates, infants and young children. Finally, we conclude with some details on accuracy, limitations and pitfalls of the technique.

Trigeminal Neuralgia Secondary to Intracranial Neoplastic Lesions: a Case Series and Comprehensive Review.

It is known that intracranial tumors may trigger trigeminal neuralgia (TN) in some patients although the exact prevalence and occurrence is not completely defined yet. In the present study, we present a case series of patients with brain tumor and a clinical diagnosis of TN as the first and main manifestation of the disease. A retrospective analysis was performed involving patients diagnosed with brain tumor whose exclusive clinical feature our department focused on was TN. In addition, a review of all published cases was performed. From January 2017 to November 2018, 718 patients with brain tumor were admitted to our department, 17 of which suffered of TN, of which 8 patients presented with at least another neurologic symptom and 9 patients presented with TN alone, with typical symptoms of stubbing electric pain in 6 cases. In our series, we found that 2.3% of patients admitted for brain tumors had TN. In 0.8% of cases, TN was the main clinical symptom. The prevalence of tumor lesion in patients with facial neuropathic pain is not defined, but it is a well-known recognized initial symptom; however, early cerebral magnetic resonance imaging (MRI) is not yet strongly recommended in patients with newly diagnosed trigeminal neuralgia. The purpose of this article is, especially in unusual cases, to show that the application of such MR techniques and preoperative evaluation may contribute to diagnosis, indication, and surgery planning.

Reference Ranges, Diagnostic and Prognostic Utility of Native T1 Mapping and Extracellular Volume for Cardiac Amyloidosis: A Meta-Analysis.

Cardiac MRI is central to the evaluation of cardiac amyloidosis (CA). Native T1 mapping and extracellular volume (ECV) are novel MR techniques with evolving utility in cardiovascular diseases, including CA. To perform a meta-analysis of the diagnostic and prognostic data of native T1 mapping and ECV techniques for assessing CA. Systematic review and meta-analysis. In all, 3520 patients including 1539 with CA from 22 studies retrieved following systematic search of Pubmed, Cochrane, and Embase. 1.5T or 3.0T/modified Look-Locker inversion recovery (MOLLI) or shortened MOLLI (shMOLLI) sequences. Meta-analysis was performed for all CA and for light-chain (AL) and transthyretin (ATTR) subtypes. Thresholds were calculated to classify native T1 and ECV values as not suggestive, indeterminate, or suggestive of CA. Area under the receiver-operating characteristic curves (AUCs) and hazards ratios (HRs) with 95% confidence intervals (95% CI) were pooled using random-effects models and Open-Meta(Analyst) software. Six studies were diagnostic, 16 studies reported T1 and ECV values to determine reference range, and six were prognostic. Pooled AUCs (95% CI) for diagnosing CA were 0.92 (0.89-0.96) for native T1 mapping and 0.96 (0.93-1.00) for ECV, with similarly high detection rates for AL- and ATTR-CA. Based on the pooled values of native T1 and ECV in CA and control subjects, the thresholds that suggested the absence, indeterminate, or presence of CA were identified as <994 msec, 994-1073 msec, and >1073 msec, respectively, for native T1 at 1.5T. Pooled HRs (95% CI) for predicting all-cause mortality were 1.15 (1.08-1.22) for native T1 mapping as a continuous parameter, 1.19 (1.01-1.40) for ECV as a continuous parameter, and 4.93 (2.64-9.20) for ECV as a binary threshold. Native T1 mapping and ECV had high diagnostic performance and predicted all-cause mortality in CA. 1 TECHNICAL EFFICACY STAGE: 2.