Purpose: To evaluate the potential of Photon-Counting Detector CT Angiography (PCD-CTA) for the post-interventional assessment of intracranial aneurysms treated with coil-embolization or clipping, compared to digital subtraction angiography (DSA). Methods: Retrospective analysis of consecutive patients treated with coils or clips between April 2023 and May 2024, who underwent PCD-CTA and, if necessary, DSA as part of their clinical routine. Polyenergetic images and spectral reconstructions were performed at different kiloelectron volt (keV) levels (40, 80 and 120) and with reconstruction kernels: Quantitative (Qr56 and Qr72) and Head vessel (Hv56 and Hv72), both with and without iterative metal artifact reduction (iMAR). Three independent readers assessed image quality using a 5-point Likert scale and region of interest analysis. A blinded, independent reading was performed to determine the presence of aneurysm remnants and intracranial vessel stenosis in the parent vessel. Results: A total of 21 patients (mean age 58 ± 14 years; range 36–74; 18 women) with intracranial, saccular aneurysms treated with either clipping (17/21) or coiling (4/21) were included. Reconstructions using smooth kernels (Hv56, Qr56) at a low keV level (40 keV) yielded increased signal- and contrast-to-noise ratios compared to sharper kernels (Hv72, Qr72) and higher keV levels (80 and 120 keV) (p < 0.001). Unexpectedly, reconstructions with iMAR negatively impacted evaluation, with only 6/21 diagnostic images at the clip site. The sensitivity of PCD-CTA for detecting aneurysm remnants was 100% (7 of 7 aneurysm clip/coil site), while specificity was 89% for patients with clips (8/9). A 100% negative predictive value was observed for all readers regarding aneurysm remnants. Conclusion: Photon-Counting CT-Angiography demonstrated adequate diagnostic value in most patients with intracranial clips. However, while coil artifacts were reduced, spectral reconstructions and iMAR were not sufficient to fully minimize these artifacts.

BACKGROUND AND PURPOSE: Radiographic shunt series are still the imaging technique of choice for radiologic evaluation of VP-shunt complications. Radiographic shunt series are associated with high radiation exposure and have a low diagnostic performance. Our aim was to investigate the diagnostic performance of whole-body ultra-low-dose CT for detecting mechanical ventriculoperitoneal shunt complications. MATERIALS AND METHODS: This retrospective study included 186 patients (mean age, 54.8 years) who underwent whole-body ultra-low-dose CT (100 kV[peak]; reference, 10 mAs). Two radiologists reviewed the images for the presence of ventriculoperitoneal shunt complications, image quality, and diagnostic confidence. On a 5-point Likert scale, readers scored image quality and diagnostic confidence (1 = very low, 5 = very high). Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Radiation dose estimation of whole-body ultra-low-dose CT was calculated and compared with the radiation dose of a radiographic shunt series. RESULTS: 34 patients positive for VP-shunt complications were correctly identified on whole-body ultra-low-dose CT by both readers. No false-positive or -negative cases were recorded by any of the readers, yielding a sensitivity of 100% (95% CI, 87.3%–100%), a specificity of 100% (95% CI, 96.9%–100%), and perfect agreement (κ = 1). Positive and negative predictive values were high at 100%. Shunt-specific image quality and diagnostic confidence were very high (median score, 5; range, 5–5). Interobserver agreement was substantial for image quality (κ = 0.73) and diagnostic confidence (κ = 0.78). The mean radiation dose of whole-body ultra-low-dose CT was significantly lower than the radiation dose of a conventional radiographic shunt series (0.67 [SD, 0.4] mSv versus 1.57 [SD, 0.6] mSv; 95% CI, 0.79–1.0 mSv; P < .001). CONCLUSIONS: Whole-body ultra-low-dose CT allows detection of ventriculoperitoneal shunt complications with excellent diagnostic accuracy and diagnostic confidence. With concomitant radiation dose reduction on contemporary CT scanners, whole-body ultra-low-dose CT should be considered an alternative to the radiographic shunt series.

Background/Objectives: Chronic subdural hematoma (cSDH) is a common disease of growing significance due to the increasing use of antithrombotic drugs and population aging. There exists conflicting observational evidence that previous treatment with angiotensin-converting enzyme (ACE) inhibitors reduces the rate of cSDH recurrence. This study assesses the hypothesis that ACE inhibitors may affect recurrence rates by altering hematoma membrane formation. Methods: All patients with chronic subdural hematoma who were operated upon in a single university hospital between 2015 and 2020 were considered for inclusion. Hematomas were classified according to their structural appearance in computed tomography (CT) imaging into one of eight subtypes. Patients’ own medication, prior to hospitalization for cSDH treatment, was noted, and the use of ACI-inhibitors was identified. Results: Of the included 398 patients, 142 (35.9%) were treated with ACE inhibitors before admission for cSDH treatment. Of these, 115 patients (81.0%) received ramipril, 13 received patients lisinopril (11.3%), and 11 patients (9.6%) received enalapril. Reflecting cardiovascular comorbidity, patients on ACE inhibitors were more often simultaneously treated with antithrombotics (63.4% vs. 42.6%; p ≤ 0.001). Hematomas with homogenous hypodense (OR 11.739, 95%CI 2.570 to 53.612; p = 0.001), homogenous isodense (OR 12.204, 95%CI 2.669 to 55.798; p < 0.001), and homogenous hyperdense (OR 9.472, 95%CI 1.718 to 52.217; p < 0.001) architectures, as well as the prior use of ACE inhibitors (OR 2.026, 95%CI 1.214 to 3.384; p = 0.007), were independently associated with cSDH recurrence. Conclusions: Once corrected for hematoma architecture, type of surgery, and use of antithrombotic medication, preoperative use of ACE inhibitors was associated with a twofold increase in the likelihood of hematoma recurrence.

Background: Young children requiring neurosurgical care frequently undergo repeated neuroimaging. Whereas CT involves exposure to ionizing radiation, conventional MRI is time-consuming and often necessitates sedation in non-cooperative children. To address these limitations, ultrafast cranial MRI (UF-MRI) based on T2-HASTE sequences was implemented at our institution in 2019 for selected indications. The aim of this study was to evaluate the real-world implementation of UF-MRI in children younger than six years of age. Methods: We retrospectively analyzed cranial MRI examinations consisting exclusively of ultrafast sequences performed between July 2019 and December 2024 in children younger than six years. Clinical settings, diagnostic adequacy, immediate consequences for patient management, and the impact on MRI and CT utilization were systematically assessed. Results: A total of 404 UF-MRI examinations were performed in 198 inpatients and outpatients (mean age: 2 years 2 months) without the need for dedicated anesthesia team support solely for imaging. Only one examination (0.2%) required same-day repetition after mild oral sedation. In 20 patients (5.0%), UF-MRI was supplemented by conventional MRI under anesthesia, most commonly for preoperative planning. Immediate clinical consequences included no change in management in 54.5% of examinations, early follow-up in 22.8%, shunt valve adjustment in 11.6%, neurosurgical intervention in 7.7%, and other measures in 5.0%. UF-MRI accounted for 24.5% of all cranial MRI examinations in this age group and was associated with a 41% reduction in CT utilization compared with the corresponding period prior to UF-MRI implementation. Conclusions: In routine clinical practice, UF-MRI provides rapid, clinically sufficient neuroimaging in young children without the need for sedation or exposure to ionizing radiation. Its implementation significantly streamlines imaging workflows, optimizes resources utilization, reduces the need for CT, and supports timely clinical decision-making, underscoring its value as a complementary imaging modality in pediatric neuroimaging.