AJNR. American journal of neuroradiology最新文献

Background and purpose: Subpial hemorrhage is an underrecognized type of hemorrhagic stroke primarily affecting neonates. Blood accumulation in the impermeable pia mater compresses the adjacent cortex, leading to injury. The consequences of this stroke type remain poorly understood. The study aims to evaluate the association between imaging findings and neurological outcomes at follow-up in neonates with subpial hemorrhage.

Materials and methods: We retrospectively included neonates with suspected subpial hemorrhage who underwent brain MRI between January 2012 and February 2024. Two pediatric neuroradiologists evaluated MRIs for subpial hemorrhage location, size, and pattern using a previously described system that classified subpial hemorrhage only (Pattern A), subpial hemorrhage with cortical injury (Pattern B), and subpial hemorrhage with cortical injury and intraparenchymal hemorrhage (Pattern C). They also assessed for medullary vein engorgement/thrombosis. We extracted demographic data, perinatal events, hospital outcomes, and Alberta Infant Motor Scale (AIMS) scores, when available. Descriptive analysis was used for demographic, clinical, and imaging findings. Fisher's exact test evaluated associations between clinical outcomes and imaging findings.

Results: Twenty-nine patients (median gestational age 38 weeks, IQR: 37-39) were included, with 82% having birthweights >2500g. Subpial hemorrhages were most commonly on the right side (66%) and in the temporal lobe (62%). Most hemorrhages measured 1-4 cm (59%). Pattern C (15/29, 52%) was associated with delayed motor development as assessed by AIMS (9/15, 60%) (p=.042), while Pattern B (10/29, 35%) was associated with near-normal motor development (6/15, 40%) (p=.044). There was no statistically significant association between concurrent superficial and deep medullary vein engorgement/thrombosis and the presence of any neurological deficit (p=.055).

Conclusions: The association between subpial hemorrhage patterns and neurological outcomes, particularly motor development, may have important prognostic and management implications. In our cohort, a pattern C of subpial hemorrhage was significantly associated with delayed motor development. Concurrent involvement of superficial and deep medullary vessels may indicate a higher risk of poor neurological outcomes. These findings highlight the importance of early intervention and monitoring in neonates presenting with subpial hemorrhage.

Abbreviations: AIMS= Alberta Infant Motor Scale; IQR= Interquartile Ranges; NICU= Neonatal Intensive Care Unit; SD= Standard Deviations.

Background and purpose: This study explores the impact of stenosis degree on outcomes of stenting compared with medical therapy alone in patients with symptomatic intracranial artery stenosis.

Materials and methods: Patients with a transient ischemic attack or nondisabling ischemic stroke, attributed to 70 to 99% stenosis of a major intracranial artery, were included. The patient cohort was drawn from the China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis (CASSISS) and the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS). The primary outcome was a composite of stroke or death within 30 days or stroke in the qualifying artery territory beyond 30 days through 1 year.

Results: Out of 806 patients, 92 patients (11%) met the primary outcome. As the degree of stenosis increased, the risk of the primary endpoint was significantly lower in the stenting group (R = -0.886, P = .03). For stenosis below or equal to 85%, stenting is worse than medical therapy given the high perioperative risk [13% vs. 8.0%, HR, 1.67, (95% CI, 1.04-2.67); P = .04]; at stenosis degree above 85%, stenting was preferred over medical therapy given the potential for better long-term prevention [14% vs. 21%, HR, 0.67, (95% CI, 0.29-1.56); P = .36].

Conclusions: Patients with higher degrees of stenosis are more likely to benefit from stenting. Patients with intracranial artery stenosis exceeding 85% may be the focus of future studies. If innovations in interventional techniques significantly reduce perioperative risk, the critical threshold of 85% as the degree of stenosis might be reconsidered.

Abbreviations: CASSISS = China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis; SAMMPRIS = Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis; ICAS = Intracranial atherosclerotic arterial stenosis; WASID = Warfarin versus Aspirin for Symptomatic Intracranial Disease; VISSIT = Vitesse Intracranial Stent Study for Ischemic Stroke Therapy; PH = proportional hazards; HR = Hazard ratio.

Backgound and purpose: This study utilizes a physics-based approach to synthesize realistic MR artifacts and train a deep learning generative adversarial network (GAN) for use in artifact reduction on EPI, a crucial neuroimaging sequence with high acceleration that is notoriously susceptible to artifacts.

Materials and methods: A total of 4,573 anatomical MR sequences from 1,392 patients undergoing clinically indicated MRI of the brain were used to create a synthetic data set using physics-based, simulated artifacts commonly found in EPI. By using multiple MRI contrasts, we hypothesized the GAN would learn to correct common artifacts while preserving the inherent contrast information, even for contrasts the network has not been trained on. A modified Pix2PixGAN architecture with an Attention-R2UNet generator was used for the model. Three training strategies were employed: (1) An "all-in-one" model trained on all the artifacts at once; (2) a set of "single models", one for each artifact; and a (3) "stacked transfer learning" approach where a model is first trained on one artifact set, then this learning is transferred to a new model and the process is repeated for the next artifact set. Lastly, the "Stacked Transfer Learning" model was tested on ADC maps from single-shot diffusion MRI data in N = 49 patients diagnosed with recurrent glioblastoma to compare visual quality and lesion measurements between the natively acquired images and AI-corrected images.

Results: The "stacked transfer learning" approach had superior artifact reduction performance compared to the other approaches as measured by Mean Squared Error (MSE = 0.0016), Structural Similarity Index (SSIM = 0.92), multiscale SSIM (MS-SSIM = 0.92), peak signal-to-noise ratio (PSNR = 28.10), and Hausdorff distance (HAUS = 4.08mm), suggesting that leveraging pre-trained knowledge and sequentially training on each artifact is the best approach this application. In recurrent glioblastoma, significantly higher visual quality was observed in model predicted images compared to native images, while quantitative measurements within the tumor regions remained consistent with non-corrected images.

Conclusions: The current study demonstrates the feasibility of using a physics-based method for synthesizing a large data set of images with realistic artifacts and the effectiveness of utilizing this synthetic data set in a "stacked transfer learning" approach to training a GAN for reduction of EPI-based artifacts.

Background and purpose: Brain [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) is critical in the diagnosis of neurodegenerative disease. Quantitative analysis with statistical parametric mapping (SPM) has been shown to improve diagnostic accuracy of FDG-PET and has been incorporated in clinical workflows. This study aimed to assess the effects of hydrocephalus on FDG PET SPM analysis accuracy, focusing on cingulate gyrus regions, which are of particular interest in dementia evaluation, and also are adjacent to the lateral ventricles.

Materials and methods: In this retrospective IRB-approved study, patients who underwent brain FDG-PET/CT or PET/MRI were evaluated. Inclusion criteria were clinical history of cognitive impairment/suspected neurodegenerative disease and MRI evidence of communicating hydrocephalus. Region-specific Z-scores for the anterior, middle, and posterior cingulate gyri (ACG, MCG, PCG), as well as for the cerebellum were generated using SPM analysis. Blinded expert qualitative assessment was performed for each anatomic region. Kappa coefficients were computed to evaluate agreement between quantitative and qualitative results. Paired nonparametric t-tests assessed Z-score differences between cingulate and cerebellar regions.

Results: The study included 48 patients (17 females, mean age 76). SPM analysis found significantly lower cingulate Z-scores compared to the cerebellum [-4.3 (ACG), -6.9 (MCG), and -3.2 (PCG), -1.2 (CBL) p < 0.0001]. Similar results were observed in the signed rank tests comparing cingulate regions to cerebellum [ACG -3.2 (SD 2.1), MCG -5.7 (SD 3.6), PCG -1.9 (SD 2.4), p < 0.001 for all 3 cingulate regions]. Kappa coefficients indicated poor agreement between SPM and qualitative assessments (kappa 0.05-0.19, p-values 0.078-0.479).

Conclusions: Our study highlights hydrocephalus as an important pitfall of FDG-PET SPM, particularly when analyzing the cingulate regions, integral to the clinical evaluation of dementia. Awareness of this pitfall can improve diagnostic accuracy and thus improve clinical outcomes in this growing patient population.

Abbreviations: FDG= [18F]fluorodeoxyglucose, PET= Positron Emission Tomography, SPM:=Statistical Parametric Mapping, SUV:= Standardized Uptake Values, NPH= Normal Pressure Hydrocephalus, MRI= Magnetic Resonance Imaging, CT= Computed Tomography, ACG= Anterior Cingulate Gyrus, MCG= Middle Cingulate Gyrus, PCG= Posterior Cingulate Gyrus, CBL= Cerebellum.

Background and purpose: Post-carotid endarterectomy (CEA) cerebral hyperperfusion (CH) can cause intracerebral hemorrhage and cognitive decline. Alterations in susceptibility in response to acetazolamide (ACZ) on 7T MRI quantitative susceptibility mapping (QSM) detects elevated CBV occurring due to impaired cerebrovascular autoregulation. We explored preoperative relative susceptibility changes on 7T MRI QSM in response to ACZ and their ability to predict CH following CEA.

Materials and methods: Sixty-three patients with uni-or bilateral cervical ICA stenosis ≥70% underwent 7T MRI at baseline and at 5, 10, 15, and 20 min after ACZ administration before surgery. The difference between the susceptibility of venous structures and surrounding brain parenchyma at each time point after ACZ administration relative to the difference at baseline (relative susceptibility difference; RSD) on QSM images was calculated in the cerebral hemisphere ipsilateral to surgery. Brain perfusion SPECT was conducted preoperatively and immediately following CEA to detect postoperative CH (≥ 100% rise in CBF postoperatively).

Results: In nine patients with postoperative CH, RSD was significantly increased at 5 or 10 min following ACZ administration (p < 0.05) but reduced at 15 and 20 min (p < 0.05). In 54 patients without postoperative CH, RSD at all four time points after ACZ administration was significantly lower than the baseline value (p < 0.05). The area under the receiver operating characteristic curve to predict postoperative CH was significantly greater in RSD₅ (0.981; 95% CI, 0.910-0.999) than in RSD₁₅ (0.872; 95% CI, 0.764-0.943) (p < 0.05) or RSD₂₀ (0.780; 95% CI, 0.658-0.874) (p < 0.01). Sensitivity, specificity, and positive and negative predictive values for RSD₅ at a cutoff near the left upper corner of the curve were 100%, 89%, 60%, and 100%, respectively. Logistic regression analysis revealed that only RSD₅ significantly predicted postoperative CH (95% CI, 455.9-4043.6; p < 0.05).

Conclusions: Changes in susceptibility on preoperative 7T MRI QSM following ACZ administration predict CH following CEA. Patients with increased RSD₅ on pre-CEA 7T MRI QSM following ACZ administration should undergo brain perfusion imaging immediately after surgery. Detection of CH on postoperative brain perfusion imaging warrants intensive blood pressure control.

Abbreviations: CEA = carotid endarterectomy; CH = cerebral hyperperfusion; OEF = oxygen extraction fraction; ACZ = acetazolamide; QSM = quantitative susceptibility mapping; 3D = three-dimensional; RSD = relative susceptibility difference; SD = standard deviation; ROC = receiver operating characteristic.

Background and purpose: Photon counting detector CT myelography is a recently described technique used for detecting spinal CSF leaks, including CSF-venous fistulas. Various image reconstruction techniques, including smoother versus sharper kernels and virtual monoenergetic images, are available with photon counting CT. Moreover, denoising algorithms have shown promise in improving sharp kernel images. No prior studies have compared image quality of these different reconstructions on photon counting CT myelography. Here, we sought to compare several image reconstructions using various parameters important for the detection of CSF-venous fistulas.

Materials and methods: We performed a retrospective review of all consecutive decubitus photon counting CT myelograms performed between 2/1/2022 and 8/1/2024 at one institution. We included patients whose studies had the following reconstructions: Br48-40 keV virtual monoenergetic reconstruction, Br56 low energy threshold (T3D), Qr89-T3D denoised with quantum iterative reconstruction, and Qr89-T3D denoised with a convolutional neural network algorithm. We excluded patients who had extradural CSF on preprocedural imaging or a technically unsatisfactory myelogram. All four reconstructions were independently reviewed by two neuroradiologists. Each reviewer rated spatial resolution, noise, presence of artifacts, image quality, and diagnostic confidence (whether positive or negative) on a 1-5 scale. These metrics were compared using the Friedman test. Additionally, noise and contrast were quantitatively assessed by a third reviewer and compared.

Results: The Qr89 reconstructions demonstrated higher spatial resolution than their Br56 or Br48-40keV counterparts. Qr89 with convolutional neural network denoising had less noise, better image quality, and improved diagnostic confidence compared to Qr89 with quantum iterative reconstruction denoising. The Br48-40keV reconstruction had the highest contrast-to-noise ratio quantitatively.

Conclusions: In our study, the sharpest quantitative kernel (Qr89-T3D) with convolutional neural network denoising demonstrated the best performance with regards to spatial resolution, noise level, image quality, and diagnostic confidence for detecting or excluding the presence of a CSF-venous fistula.

Abbreviations: CNR = contrast-to-noise ratio; CVF = CSF-venous fistula; EID = energy integrating detector; PCD = photon counting detector; PCD-CTM = photon counting detector CT myelography; ROI = region of interest; SNR = signal-to-noise ratio; SIH = spontaneous intracranial hypotension; T3D = low-energy threshold; UHR = ultra-high resolution.

Background/purpose: Determine the most common MRI interpretation errors in patients with MRE according to our experience in a tertiary academic center with a large volume epilepsy program, in order to raise awareness of the 'blind spots' in imaging patients with MRE and to highlight the importance of combining clinical and electroencephalographic information to obtain the most accurate diagnosis.

Materials and methods: This is a retrospective observational study. All MRE-patients who underwent MRI brain (on 3 Tesla, with dedicated epilepsy protocol), and who were discussed at the weekly interdisciplinary epilepsy conference in our center between January 2008 and July 2023 were included. The initial MRI interpretation and final MRI interpretation results were reviewed.

Results: 886 patients with MRE were included. 300 patients were MRI-negative (33.86%), diagnoses were missed in 95 patients (10.7%), a second diagnosis was missed in patients with dual pathologies in 42 patients (4.74%), findings were misinterpreted in 4 patients (0.45%), an overcall was made in 2 patients (0.2%), and in 5 patients the correct diagnosis was discussed but erroneously deemed absent on initial interpretation (0.56%), resulting in a total of 148 discrepant MRI reports.MTS comprised the most common pathology encountered overall, followed by encephalomalacia related to prior insult, enlarged amygdala, malformations of cortical development, cavernoma and ulegyria.The relative proportion of missed focal cortical dysplasia, encephalocele and enlarged amygdala accounted for the commonest misses/misdiagnoses.

Conclusion: Evaluation of patients with MRE requires excellent inter-disciplinary care. Input from all members of the interdisciplinary team is essential for accurate interpretation of MRI in MRE patients for the neuroradiologist.We hope to inform radiologists of commonly overlooked pathologies in MRI brain interpretation for patients with epilepsy. In doing so, we want to maximize the yield of initial MRI interpretation in these patients.

Abbreviations: EA, enlarged amygdala; EEG, electroencephalogram; EMR, electronic medical record, FCD, focal cortical dysplasia; MCD, Malformations of Cortical Development; MEG, Magnetoencephalography; MRE, medically refractory epilepsy; MTS, mesial temporal sclerosis; TLE, temporal lobe epilepsy; Positron emission tomrgrpahy (PET), Subtraction Ictal SPECT Co-registered to MRI (SISCOM) SCNH, subcortical nodular heterotopia.

Background and purpose: Superior semicircular canal dehiscence can be detected on temporal bone MR images. Radiologists often recommend confirmation with temporal bone CT due to reported lower MRI positive predictive value. The value of these recommendations is unclear given that CT overestimates dehiscence due to volume averaging and that only a small proportion of patients with dehiscence on CT suffer from dehiscence syndrome. We thus evaluated final diagnoses and outcomes in patients who adhered to the recommended additional CT.

Materials and methods: This retrospective cohort observational study, performed at a multi-institution healthcare system, included consecutive temporal bone MRI reports 6/1/2021-5/31/2022 with a recommendation for additional temporal bone CT. We recorded: whether CT was performed, dehiscence present on CT, symptoms, final diagnosis, treatment decisions, and outcomes. Actionability elements (complete containing imaging modality, time frame, and rationale; unambiguous; unconditional; without multiplicity; and without alternate language) of the recommendations were extracted from a prior data set. Descriptive statistics were performed. A binomial generalized linear model was used to test the correlation of ambiguous recommendation language with recommendation adherence.

Results: Summarize actual data. 5109 temporal bone MRI examinations were performed and interpreted by 34 radiologists. 187/5109 reports (3.7%) included a recommendation for additional temporal bone CT including 101/5109 (2.0%) specifically for suspected superior semicircular canal dehiscence. While 22% (22/101) of these recommended examinations were performed, only 32% of these (7/22) confirmed dehiscence. Ultimately, only 1 patient was diagnosed with dehiscence syndrome and was managed conservatively. No recommendations for additional imaging (0/101) met actionable criteria and 76.2% (77/101) were ambiguous. Ambiguous recommendations had 0.54 lower, but not statistically significant, odds of being performed (95% CI: 0.19-1.6, p=0.25).

Conclusions: Radiologist recommendations for temporal bone CT in the setting of questionable superior semicircular canal dehiscence findings on MRI appear to have negligible clinical value and thus it is likely most appropriate to report possible SSCD in the MRI report impression without recommending further imaging.

Abbreviations: SSCD= superior semicircular canal dehiscence.

Background and purpose: First-degree relatives of aneurysmal subarachnoid hemorrhage patients face elevated risks for intracranial aneurysm development and aneurysmal subarachnoid hemorrhage, which both occur more often in women. Anatomical variants of the circle of Willis affect its hemodynamics and are associated with unruptured intracranial aneurysms. It is unknown if these findings apply to patients with a familial predisposition for these conditions, and if they are sex-specific. We therefore assessed if anatomical circle of Willis variants are associated with intracranial aneurysms identified at screening in individuals with a familial predisposition, and if these associations are sex-specific.

Materials and methods: Individuals with and without intracranial aneurysms, identified at MRA-TOF screening, were compared. Circle of Willis arterial diameters were measured to identify anatomical variants, categorized into six types for both the anterior and posterior parts. Logistic regression was used for comparison, adjusted for age, hypertension, and the cohorts the individuals were part of, and stratified for sex-specific subgroups.

Results: Of all 1,291 included individuals, 94 (7.3%) had aneurysms. A normal anterior variant was less common among individuals with aneurysms (OR 0.59, 95% CI 0.37-0.93). This effect was only observed in women (OR 0.45, 95% CI 0.25-0.80), and not in men (OR 1.39, 95% CI 0.57-3.35). The variant with anterior communicating artery hypoplasia or absence was more common in individuals with aneurysms (OR 1.61, 95% CI 1.03-2.54). This effect was observed in both women (OR 1.62, 95% CI 0.95-2.75) and men (OR 1.37, 95% CI 0.55-3.41). No differences were found for variants of the posterior part of the circle of Willis.

Conclusions: Women with intracranial aneurysms identified at screening less frequently had a normal anterior part of the circle of Willis compared to those without aneurysms. Additionally, individuals with aneurysms more often had anterior communicating artery hypoplasia or absence, which association was not sex-specific. These anatomical variations may enhance the effectiveness of screening for intracranial aneurysms.

Abbreviations: ACA = anterior cerebral artery; Acom = anterior communicating artery; ADPKD = autosomal dominant polycystic kidney disease; aSAH = aneurysmal subarachnoid hemorrhage; CoW = circle of Willis; PCA = posterior cerebral artery; Pcom = posterior communicating artery; UIA = unruptured intracranial aneurysm; UMCU = University Medical Center Utrecht.