AJNR. American journal of neuroradiology最新文献

High-grade gliomas are the most frequent primary brain tumors, yet extraneural metastasis is exceedingly rare. This is in part secondary to the relatively poor survival of these patients and likely the shielding effect of the blood-brain barrier. Given the rarity of extraneural metastasis, the pathophysiology and imaging appearance of extraneural metastasis is under-reported and poorly understood. In this case series we present 6 patients with pathology-confirmed high-grade glioma and extraneural head and neck metastasis. We highlight imaging features of metastasis on CT, MRI, and PET/CT. We also explore potential correlations and pathophysiology of high-grade glioma metastasis to the head and neck region.

Background and purpose: Cerebral angiography remains crucial for detailed characterization and preoperative assessments for intracranial aneurysm. Despite its diagnostic importance, cerebral angiography poses challenges due to its invasiveness, the risk of neurologic complications, and radiation exposure. To investigate the impact of head posture on lens radiation exposure during cerebral angiography, this study focused on the correlation between radiation doses to the eye lens, head flexion angles, and head size.

Materials and methods: A retrospective analysis was performed on 20 patients who underwent cerebral angiography for unruptured intracranial aneurysms between October and November 2022. Radiation doses to the lens, which were measured in a prior prospective study by using photoluminescent glass dosimeters, were analyzed alongside head flexion angles, anterior-posterior (AP) head diameters, and kerma-area product (KAP) to evaluate their correlation with lens radiation exposure. The lateral radiation source is located on the left side of the patients.

Results: The cohort consisted of 20 patients (60% women, mean age: 62.3 ± 9.9 years). The radiation dose to the left eye (the eye closer to the x-ray source) was 2.8 times higher than that to the right eye (9.18 ± 3.31 mGy versus 3.3 ± 0.60 mGy, P < .001). A strong positive correlation was observed between the left eye lens dose and head flexion angle (R = 0.815, P < .001). While the AP head diameter correlated significantly with the flexion angle, it showed no significant correlation with lens dose. The KAP was inversely correlated with both the left lens dose (R = -0.597, P = .005) and the flexion angle (R = -0.689, P < .001).

Conclusions: Our findings underscore the meaningful impact of head posture on lens radiation exposure during cerebral angiography. Adjusting head positioning may provide a practical approach to reduce radiation exposure to the lens. Furthermore, it is worth noting that the left lens received more radiation than the right, likely due to the x-ray source being on the left side of the patient.

Background and purpose: Clinically, hemorrhagic transformation (HT) after mechanical thrombectomy (MT) is a common complication. This study aimed to investigate the value of clinical factors, CT signs, and radiomics in the differential diagnosis of high-density areas (HDAs) in the brain after MT in patients with acute ischemic stroke with large-vessel occlusion (AIS-LVO).

Materials and methods: A total of 156 eligible patients with AIS-LVO in Center I from December 2015 to June 2023 were retrospectively enrolled and randomly divided into training (n = 109) and internal validation (n = 47) sets at a ratio of 7:3. The data of 63 patients in Center II were collected as an external validation set. According to the diagnostic criteria, the patients in the 3 data sets were divided into an HT group and a non-HT group. The clinical and imaging data from Centers I and II were used to construct a clinical factor and CT-sign model, a radiomics model, and a combined model by logistic regression. Receiver operating characteristic analysis was used to evaluate the diagnostic efficacy of each model in the 3 data sets.

Results: Clinical blood glucose and the maximum cross-sectional area on CT were associated with the HT or non-HT of the HDA according to multivariate logistic regression analyses (P < .05). Among the 3 models, the combined model had the highest diagnostic efficiency, with area under the curve values of 0.895, 0.882, and 0.820 in the 3 data sets, which were significantly greater than the area under the curve values of the radiomics model (0.887, 0.898, 0.798) and clinical factor and CT-sign model (0.831, 0.744, 0.684).

Conclusions: The combined model based on radiomics had the best performance, indicating that radiomics features can be used as imaging biomarkers to aid in the clinical judgment of the nature of HDA after MT.

Background and purpose: This animal study was designed to evaluate in vivo the acute and short-term safety and efficacy of the new Artisse intrasaccular device (ISD) for aneurysm occlusion and to gain knowledge about the behavior in the aneurysms.

Materials and methods: The device was implanted in 7 white New Zealand rabbits with bifurcation aneurysms. Immediate and 90-day angiographic follow-up as well as histologic and scanning electron microscope imaging were evaluated.

Results: Immediate postinterventional angiograms showed excellent flow reduction in all aneurysms. Progressive improvements of occlusion rate could be observed in 5 of 7 aneurysms. One device migration was noted due to undersizing, resulting in corresponding worsening of occlusion rate. Three-month microscopic examinations demonstrated excellent biocompatibility. Notably, the Artisse ISD showed increased connective tissue formation within the aneurysm sac, which correlated with the angiographic results.

Conclusions: The new Artisse ISD adapted well to aneurysm morphology and created immediate contrast stasis and excellent neck coverage. While angiographic results showed only moderate adequate occlusion at 3 months, histologic data showed excellent biocompatibility and good connective tissue formation within the aneurysm sac in all aneurysms treated with the Artisse ISD. Sizing and correct positioning appear to be crucial for adequate occlusion.

Background and purpose: Isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion classify adult-type diffuse gliomas into 3 tumor subtypes with distinct prognoses. We aimed to evaluate the performance of edited MR spectroscopy for glioma subtyping in a clinical setting, via the quantification of D-2-hydroxyglutarate (2HG) and cystathionine. The delay between this noninvasive classification and the integrated histomolecular analysis was also quantified.

Materials and methods: Subjects with presumed low-grade gliomas eligible for surgery (cohort 1) and subjects with IDH-mutant gliomas previously treated and with progressive disease (cohort 2) were prospectively examined with a single-voxel Mescher-Garwood point-resolved spectroscopy sequence at 3T. Spectra were quantified using LCModel. The Cramér-Rao lower bounds threshold was set to 20%. Integrated histomolecular analysis according to the 2021 WHO classification was considered as ground truth.

Results: Thirty-four consecutive subjects were enrolled. Due to poor spectra quality and lack of histologic specimens, data from 26 subjects were analyzed. Twenty-one belonged to cohort 1 (11 women; median age, 42 years); and 5, to cohort 2 (3 women; median age, 48 years). Edited MR spectroscopy showed 100% specificity for detection of IDH-mutation and 91% specificity for the prediction of 1p/19q-codeletion status. Sensitivities for the prediction of IDH and 1p/19q codeletion were 69% and 33%, respectively. The median Cramér-Rao lower bounds values were 16% (13%-28%) for IDH-mutant and 572% (554%-999%) for IDH wild type tumors. The time between MR spectroscopy and surgery was longer for low-grade than for high-grade gliomas (P = .03), yet the time between MR spectroscopy and WHO diagnosis did not differ between grades (P = .07), possibly reflecting molecular analyses-induced delays in high-grade gliomas.

Conclusions: Our results, acquired in a clinic setting, confirmed that edited MR spectroscopy is highly specific for both IDH-mutation and 1p/19q-codeletion predictions and can provide a faster prognosis stratification. In the upcoming IDH-inhibitor treatment era, incorporation of edited MR spectroscopy into clinical workflow is desirable.

Background and purpose: Early opacification of the renal collecting system during CT myelography (CTM) performed for the evaluation of spontaneous intracranial hypotension (SIH) has been demonstrated in prior studies. However, these investigations often included CTMs scanned >30 minutes after intrathecal contrast injection, a longer delay than the myelographic techniques used in current practice. The purpose of this study was to determine whether renal contrast excretion (RCE) measured during this earlier time period (≤30 minutes) can discriminate patients with SIH from patients without SIH.

Materials and methods: A single-center, retrospective cohort of consecutive patients presenting for evaluation of possible SIH between July 2021 and May 2022 was studied. RCE was measured in both renal hila by using standardized (5-15 mm³) ROIs. Receiver operating characteristic (ROC) curves were constructed by comparing RCE between patients with SIH and patients without SIH in the overall cohort and within the subgroup of patients with negative myelograms.

Results: The study cohort included 190 subjects. Both unadjusted and adjusted models demonstrated a statistically significant increase in renal contrast attenuation among patients with SIH compared with those without SIH (P values ≤.001). The ROC curve showed moderate discrimination between these groups (area under the ROC curves [AUC] 0.76). However, by using clinically meaningful test criteria of sensitivity >90% or specificity >90%, the 2 corresponding threshold hounsfield units (HU) values resulted in low specificity of 31.3% and sensitivity of 50.8%. Subgroup analysis of patients with negative myelograms showed poorer performance in discriminating SIH+ from SIH- (AUC 0.62). In this subgroup, using similar test criteria of sensitivity >90% or specificity >90 resulted in low specificities and sensitivities, at 26.0% and 37.5%, respectively.

Conclusions: We found a statistically significant positive association between RCE and SIH diagnosis during early-phase CTM; however, clinically useful thresholds based on cutoff values for renal HU resulted in poor sensitivities or specificities, with substantial false-positives or false-negatives, respectively. Thus, while we confirmed statistically significant differences in RCE in the ≤30-minute period, in keeping with prior investigations of more delayed time periods, overlap in renal attenuation values prevented the development of clinically useful threshold values for discriminating SIH+ from SIH- patients.

Background and purpose: Hemodynamic factors significantly influence the onset, progression, and rupture of intracranial aneurysms (IAs). Current rupture risk prediction scores focus primarily on the clinical, anatomic, and morphologic aspects. This study aimed to investigate the hemodynamic characteristics differences between ruptured and unruptured IAs.

Materials and methods: Conducted from July 2021 to July 2022, this prospective cohort study involved patients with ruptured and unruptured IAs undergoing DSA. Hemodynamic characteristics were assessed by using the AneurysmFlow tool. Hemodynamic, clinical, anatomic, and morphologic parameters were compared between ruptured and unruptured IA groups.

Results: The study included 127 patients with 135 aneurysms (67 ruptured, 68 unruptured). Complex flow patterns (type 3 and 4) were observed more frequently in ruptured aneurysms compared with unruptured aneurysms (OR, 5.57; 95% CI, 2.49-12.45; P < .001) in univariate analysis, and were also more common in unruptured aneurysms associated with daughter sac features (P = .015). The mean aneurysm flow amplitude (MAFA) was lower in ruptured aneurysms, and associated with lower flow velocity in the parent artery related to vasospasm. MAFA in the aneurysmal dome or any additional daughter sacs was lowest compared with other regions inside the aneurysms. The technical failure rate of AneurysmFlow measurements was 8.5% (12 of 139 patients). Additionally, hypertension (OR, 0.42; 95% CI, 0.30-0.54; P < .001), bifurcation location (anterior communicating artery/anterior cerebral artery/MCA/posterior communicating artery/posterior circulation) (OR, 0.17; 95% CI, 0.05-0.29; P = .005), and irregular shape (OR, 0.19; 95% CI, 0.05-0.35; P = .012) were identified as independently associated with rupture.

Conclusions: Complex flow patterns identified on the AneurysmFlow tool are significantly more common in ruptured and unruptured aneurysms associated with daughter sac features. The lowest MAFA in the aneurysmal dome and daughter sacs likely indicates specific pathophysiologic changes within the aneurysm wall associated with rupture incidence. Hypertension, bifurcation location, and an irregular shape are independently associated with the risk of rupture. Further multicenter studies with larger sample sizes are needed to validate these findings.

Background and purpose: Normal pressure hydrocephalus (NPH) is a diagnostic challenge because its clinical symptoms and imaging appearance resemble normal aging and other forms of dementia. Identifying NPH is essential so that patients can receive timely treatment to improve gait distortion and quality of life. An automated marker of NPH was developed and evaluated on clinical CT images, and its utility was assessed in a large patient cohort.

Materials and methods: A retrospective review was conducted of CT images from 306 tap test-responsive patients with NPH between January 2015 and January 2022. Control CT images were obtained from patients in the emergency department who were evaluated for headache and had unremarkable CT findings between June 2021 and August 2022. The ventricle-to-subarachnoid volume ratio (VSR) was automatically calculated by the imaging software and used as a predictor of NPH in linear regression modeling with adjustment for age and sex. The correlations of VSR with age, sex, and the receiver operating characteristic were computed.

Results: VSR was significantly greater in patients with NPH than controls (P < .001). Importantly, VSR was not significantly correlated with age (P = .56, R² = 0.001). VSR identifies NPH with a sensitivity and specificity of 94.1% and 92.5%, respectively, with an area under the receiver operating characteristic curve of 0.99 (95% CI 0.975-0.995).

Conclusions: Automated assessment of the VSR on head CT images identified probable NPH with 93% accuracy. The assessment of a large cohort of patients with NPH supports the generalizability of clinical screening of CT images. Moreover, the results support the utility of ventricle-to-sulcal concordance often used by radiologists but not currently a part of the accepted guidelines for imaging markers of NPH.

Background and purpose: DWI is crucial for detecting infarction stroke. However, its spatial resolution is often limited, hindering accurate lesion visualization. Our aim was to evaluate the image quality and diagnostic confidence of deep learning (DL)-based super-resolution reconstruction for brain DWI of infarction stroke.

Materials and methods: This retrospective study enrolled 114 consecutive participants who underwent brain DWI. The DWI images were reconstructed with 2 schemes: 1) DL-based super-resolution reconstruction (DWI_DL); and 2) conventional compressed sensing reconstruction (DWI_CS). Qualitative image analysis included overall image quality, lesion conspicuity, and diagnostic confidence in infarction stroke of different lesion sizes. Quantitative image quality assessments were performed by measurements of SNR, contrast-to-noise ratio (CNR), ADC, and edge rise distance. Group comparisons were conducted by using a paired t test for normally distributed data and the Wilcoxon test for non-normally distributed data. The overall agreement between readers for qualitative ratings was assessed by using the Cohen κ coefficient. A P value less than .05 was considered statistically significant.

Results: A total of 114 DWI examinations constituted the study cohort. For the qualitative assessment, overall image quality, lesion conspicuity, and diagnostic confidence in infarction stroke lesions (lesion size <1.5 cm) improved by DWI_DL compared with DWI_CS (all P < .001). For the quantitative analysis, edge rise distance of DWI_DL was reduced compared with that of DWI_CS (P < .001), and no significant difference in SNR, CNR, and ADC values (all P > .05).

Conclusions: Compared with the conventional compressed sensing reconstruction, the DL-based super-resolution reconstruction demonstrated superior image quality and was feasible for achieving higher diagnostic confidence in infarction stroke.