Clinical Neuroradiology最新文献

Background: The benefits of flow diversion (FD) versus endosaccular coiling (EC) in small and medium-sized proximal saccular aneurysms of anterior circulation, amenable to both methods, remain not well-established. This study aimed to compare the efficacy and safety of FD vs EC and evaluate the triggers of treatment modality choice in the aforementioned setting.

Methods: The study had a retrospective design. Raw sample included 154 FD and 190 EC consecutively enrolled cases. All aneurysms were saccular, sized 4-14 mm, located at intradural ICA or A1/M1, not acutely ruptured and previously untreated. Median lesion size was 6.6 mm (90% < 10 mm), median neck diameter‑3.7 mm. Matched cohorts were 67 cases each, PS difference < 0.1 probit SD, all covariates: size, neck, location, shape, angle, multiplicity, rupture history, age, and incorporated arterial branch. Follow-up DSA available for 94.2% of raw sample at median 9 months.

Results: In both raw and matched samples respectively, FD versus EC demonstrated higher rates of target aneurysm total occlusion (76.4% vs 53.2%, p < 0.001 and 80.3% vs 49.2%, p < 0.001), lower of rates of intraoperative technical adverse events (7.3% vs 21.4%, p < 0.001 and 9% vs 22.4%, p = 0.032) and retreatment (raw‑2.6% vs 15.4%, p < 0.001, matched‑1.5% equal). Rates of neurological morbidity and death were similar. The choice of FD was triggered by neck size and ratio, paraophthalmic location (OR = 2.57), multiplicity (OR = 4.1) and incorporated arterial branch (OR = 4.82), p < 0.001. Incorporated branch was associated with incomplete occlusion in both treatment modalities (p < 0.01).

Conclusion: In this study FD demonstrated higher rates of target aneurysm total occlusion, lower rates of intraoperative technical adverse events and similar rates of neurological morbidity and death, compared to EC.

Purpose: Photon-Counting Detector CT is characterized by enhanced image post-processing capabilities. The diagnostic accuracy of PCD-CT angiography (PCD-CTA) in assessing intracranial stents (ICS) and flow diverters (FD) has yet to be compared with digital subtraction angiography (DSA).

Methods: Retrospective analysis of all consecutive patients who underwent ICS or FD implantation between April 2023 and May 2024. Polyenergetic images, along with virtual monoenergetic imaging (VMI), pure lumen (PL) and iodine (IOD) reconstructions were assessed by three readers using a 5-point Likert scale and defined regions of interest (ROIs). A blinded analysis was performed to identify relevant lumen reduction. The diagnostic accuracy of PCD-CTA was compared to DSA by calculating the area under the receiver operating characteristic curve.

Results: A total of 18 patients (mean age 59 ± 13 years; 14 women) with 14 implanted ICS and 10 FD were analyzed. Across all pairwise comparisons, pooled VMI reconstructions demonstrated higher ratings and signal-to-noise ratios compared to IOD, PL and UHR reconstructions (p < 0.001 for all comparisons). In the pooled assessment of DSA of in-stent vessel lumen 18 (11%) of the 162 vessel segments and 6 (33%) of the 18 patients presented relevant narrowing of the in-stent vessel lumen. The sensitivity of PCD-CTA for detecting stenosis was 100% (18 of 18 in-stent vessel segments), while specificity was 89% (128/144 in-stent vessel segments). All readers reported a 100% negative predictive value (128/128 in-stent vessel segments).

Conclusion: Photon-Counting Detector CT might provide a reliable assessment of intracranial vessels following stent or flow diverter implantation comparable to DSA in many cases.

Background: The anatomy of the proximal anterior cerebral artery (ACA) and its branches, including the recurrent artery of Heubner (RAH) and medial lenticulostriate arteries (MLSAs), is known for frequent variations. Impairment of these branches can result in severe consequences, including neurological deficits or cognitive impairment. This study aimed to analyze these branches and their variations in vivo, using data from 3D rotational angiographies (3D-RA).

Material and methods: We reviewed 3D-RAs of 209 hemispheres from 191 patients with pathologies remote from the region of interest. The presence, origin and course of the RAH were investigated. Delineation, origin and number of perforator vessels originating from the A1 segment (MLSAs) were assessed.

Results: The RAH was observed in 151 hemispheres (72%), including a single RAH in 144 (69%) and a doubled RAH in 7 (3%) hemispheres. In 37% of cases, the RAH originated from the A1 segment, in 56% from the A1/A2 transition, and in 7% from the A2 segment. In the presence of RAH, additional MLSAs originating from the A1 segment were present in 25% of hemispheres. A weak negative correlation was identified between the presence of one or two RAH and the frequency of additional MLSAs.

Conclusion: The study revealed significant differences in the presence and anatomical course of RAH and MLSAs compared to previous research. The findings highlight the importance of 3D-RA in visualizing the complex anatomy of the ACA, particularly to avoid complications during surgical or endovascular procedures.

Purpose: To investigate the shared and distinct alterations in hippocampal subfield atrophy and functional connectivity (FC) in Parkinson's disease (PD) with normal cognition (PD-NC), PD with mild cognitive impairment (PD-MCI) and unspecified MCI (U-MCI).

Methods: A total of 294 participants were included from two centers (30 PD-NC, 86 PD-MCI, 76 U-MCI, and 102 healthy controls (HC)). Comparisons of hippocampal subfield volumes were conducted among groups. Seed-based FC was calculated to assess abnormalities between hippocampal subfields and cortical regions.

Results: Compared to HC, PD-NC group showed volumetric reductions in the right cornu ammonis (CA) 2/3, granule cell layer of the dentate gyrus (GC-DG), and CA4 subfields, while PD-MCI group exhibited bilateral volumetric reductions in the same subfields. PD-MCI patients exhibited increased FC between the bilateral GC-DG/CA4 subfield and the posterior default mode network (pDMN), as well as between the right GC-DG/CA4 subfield and the calcarine, in comparison to PD-NC. U‑MCI patients displayed smaller volume in the right CA4 compared to HC. Decreased FC of the hippocampus with the widespread visual network was observed in the PD-MCI group compared to the U‑MCI group.

Conclusions: PD-MCI is associated with structural vulnerability of hippocampal subfields in the CA2/3, GC-DG, and CA4 subfields, impacting FC with pDMN and visual network. Smaller scope of hippocampal subfields atrophy but weaker hippocampus-visual network FC abnormalities in U‑MCI relative to PD-MCI may suggest distinct progression mechanisms between these two conditions.

Background: Clinical evaluation of Artificial Intelligence (AI)-based Precise Image (PI) algorithm in brain imaging remains limited. PI is a deep-learning reconstruction (DLR) technique that reduces image noise while maintaining a familiar Filtered Back Projection (FBP)-like appearance at low doses. This study aims to compare PI, Iterative Reconstruction (IR), and FBP-in improving image quality and enhancing lesion detection in 1.0 mm thin-slice brain computed tomography (CT) images.

Methods: A retrospective analysis was conducted on brain non-contrast CT scans from August to September 2024 at our institution. Each scan was reconstructed using four methods: routine 5.0 mm FBP (Group A), thin-slice 1.0 mm FBP (Group B), thin-slice 1.0 mm IR (Group C), and thin-slice 1.0 mm PI (Group D). Subjective image quality was assessed by two radiologists using a 4- or 5‑point Likert scale. Objective metrics included contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and image noise across designated regions of interest (ROIs).

Results: 60 patients (65.47 years ± 18.40; 29 males and 31 females) were included. Among these, 39 patients had lesions, primarily low-density lacunar infarcts. Thin-slice PI images demonstrated the lowest image noise and artifacts, alongside the highest CNR and SNR values (p < 0.001) compared to Groups A, B, and C. Subjective assessments revealed that both PI and IR provided significantly improved image quality over routine FBP (p < 0.05). Specifically, Group D (PI) achieved superior lesion conspicuity and diagnostic confidence, with a 100% detection rate for lacunar lesions, outperforming Groups B and A.

Conclusions: PI reconstruction significantly enhances image quality and lesion detectability in thin-slice brain CT scans compared to IR and FBP, suggesting its potential as a new clinical standard.

Purpose: We evaluated a dedicated dose-reduced UHR-CT for head and neck imaging, combined with a novel deep learning reconstruction algorithm to assess its impact on image quality and radiation exposure.

Methods: Retrospective analysis of ninety-eight consecutive patients examined using a new body weight-adapted protocol. Images were reconstructed using adaptive iterative dose reduction and advanced intelligent Clear-IQ engine with an already established (DL-1) and a newly implemented reconstruction algorithm (DL-2). Additional thirty patients were scanned without body-weight-adapted dose reduction (DL-1-SD). Three readers evaluated subjective image quality regarding image quality and assessment of several anatomic regions. For objective image quality, signal-to-noise ratio and contrast-to-noise ratio were calculated for temporalis and masseteric muscle and the floor of the mouth. Radiation dose was evaluated by comparing the computed tomography dose index (CTDIvol) values.

Results: Deep learning-based reconstruction algorithms significantly improved subjective image quality (diagnostic acceptability: DL‑1 vs AIDR OR of 25.16 [6.30;38.85], p < 0.001 and DL‑2 vs AIDR 720.15 [410.14;> 999.99], p < 0.001). Although higher doses (DL-1-SD) resulted in significantly enhanced image quality, DL‑2 demonstrated significant superiority over all other techniques across all defined parameters (p < 0.001). Similar results were demonstrated for objective image quality, e.g. image noise (DL‑1 vs AIDR OR of 19.0 [11.56;31.24], p < 0.001 and DL‑2 vs AIDR > 999.9 [825.81;> 999.99], p < 0.001). Using weight-adapted kV reduction, very low radiation doses could be achieved (CTDIvol: 7.4 ± 4.2 mGy).

Conclusion: AI-based reconstruction algorithms in ultra-high resolution head and neck imaging provide excellent image quality while achieving very low radiation exposure.

Purpose: To determine the radiological prevalence of superior semicircular canal (SSC) dehiscence in a Japanese cohort using ultra-high-resolution (0.2 mm slice thickness) photon-counting detector CT (PCD-CT) and compare it with historical data from cadaveric and conventional CT studies.

Methods: This study involved a retrospective analysis of 402 temporal bones from consecutive 201 patients (age range 0-87 years; mean 41.0 ± 26.5 years) who underwent temporal bone PCD-CT for various otologic indications, none of whom had a pre-existing diagnosis of superior semicircular canal dehiscence syndrome (SSCDS). SSC bone thickness was measured, and the presence of dehiscence or thinning was assessed using multiplanar reconstructions, primarily in the Pöschl plane. For cases with identified dehiscence or thinning, a retrospective review of clinical and audiological data was performed.

Results: The mean thickness of the bone overlying the SSC was 0.87 ± 0.50 mm (range 0-3.52 mm). A definite dehiscence was identified in only 1 of the 402 temporal bones, yielding a radiological prevalence of 0.25% (95% CI: 0.00%-1.54%). Significant thinning of the SSC roof, where the bone was present but too thin to be resolved by the measurement caliper, was noted in an additional 12 temporal bones (2.99%, 95% CI: 1.66%-5.20%). Clinical review revealed that the single case of dehiscence was asymptomatic, and in the thinning cases, otologic symptoms were attributable to co-existing pathologies.

Conclusions: The radiological prevalence of SSC dehiscence identified with 0.2 mm PCD-CT is substantially lower than that reported by most conventional CT studies and closely approximates the true anatomical prevalence of 0.4-0.6% established in cadaveric studies. This finding suggests that the ultra-high spatial resolution of PCD-CT significantly reduces or eliminates false-positive findings attributable to partial volume effects, representing a new benchmark for the accurate radiological assessment of SSCDS.

Introduction: Scatter radiation during interventional neuroradiological (INR) procedures is potentially harmful to the operator and cath-lab staff. Enhanced radiation protection devices (ERPDs) aim to improve safety by minimizing scatter radiation in addition to standard and personal protective equipment (PPE). This study evaluated the efficacy of a novel ERPD in INR.

Methods: Radiation exposure of the main operator was estimated by measuring the local dose rate at the examination position. An anthropomorphic patient whole body phantom was used simulating a standard INR procedure. The relative dose reductions were determined for the following settings: a) MasterPeace (Texray AB, Sweden) combined with ceiling-suspended lead screen (Mavig, Germany) compared to no shielding. b) MasterPeace combined with ceiling-suspended lead screen, compared to standard radiation protection consisting of a table-side curtain for lower body protection (Kenex, UK) and ceiling-suspended lead screen. Scatter radiation was measured at various operator heights (70, 130 and 160 cm) across seven routine projection angles using a biplane angio-suite (Artis zee, Siemens Healthineers, Germany).

Results: (a) The mean scatter radiation shielding effect was 98.5% compared to no shielding across all measured heights and angular projections when used in combination with a ceiling-suspended lead screen. (b) The mean scatter radiation shielding effect was 79.7% compared to standard radiation protection for all measured heights and angular projections. The shielding efficacy ranged from 93.1% for the PA projection to 31.8% for LAO30/CAU30; and from 87.0% at 70 cm to 39.5% at 160 cm.

Conclusions: This phantom study demonstrates that the MasterPeace is highly effective and provides relevant radiation protection in addition to existing standard and personal protection equipment. Clinical evaluation in INR procedures is underway.