Improving advanced intraoperative MRI methods during pediatric neurosurgery.

Advanced intraoperative MR images (ioMRI) acquired during the resection of pediatric brain tumors could offer additional physiological information to preserve healthy tissue. With this work, we aimed to develop a protocol for ioMRI with increased sensitivity for arterial spin labeling (ASL) and diffusion MRI (dMRI), optimized for patient positioning regularly used in the pediatric neurosurgery setting. For ethical reasons, ASL images were acquired in healthy adult subjects that were imaged in the prone and supine position. After this, the ASL cerebral blood flow (CBF) was quantified and compared between both positions. To evaluate the impact of the RF coils setups on image quality, we compared different setups (two vs. four RF coils) by looking at T1-weighted (T1w) signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), as well as undertaking a qualitative evaluation of T1w, T2w, ASL, and dMR images. Mean ASL CBF did not differ between the surgical prone and supine positions in any of the investigated regions of interest or the whole brain. T1w SNR (gray matter: p = 0.016, 34% increase; white matter: p = 0.016, 32% increase) and CNR were higher (p = 0.016) in the four versus two RF coils setups (18.0 ± 1.8 vs. 13.9 ± 1.8). Qualitative evaluation of T1w, T2w, ASL, and dMR images resulted in acceptable to good image quality and did not differ statistically significantly between setups. Only the nonweighted diffusion image maps and corticospinal tract reconstructions yielded higher image quality and reduced susceptibility artifacts with four RF coils. Advanced ioMRI metrics were more precise with four RF coils as the standard deviation decreased. Taken together, we have investigated the practical use of advanced ioMRI during pediatric neurosurgery. We conclude that ASL CBF quantification in the surgical prone position is valid and that ASL and dMRI acquisition with two RF coils can be performed adequately for clinical use. With four versus two RF coils, the SNR of the images increases, and the sensitivity to artifacts reduces.

Prophylactic pectoralis major flap to compensate for increased risk of pharyngocutaneous fistula in laryngectomy patients with low skeletal muscle mass (PECTORALIS): study protocol for a randomized controlled trial.

BACKGROUND: Total laryngectomy (TL) is a surgical procedure commonly performed on patients with advanced laryngeal or hypopharyngeal carcinoma. One of the most common postoperative complications following TL is the development of a pharyngocutaneous fistula (PCF), characterized by a communication between the neopharynx and the skin. PCF can lead to extended hospital stays, delayed oral feeding, and compromised quality of life. The use of a myofascial pectoralis major flap (PMMF) as an onlay technique during pharyngeal closure has shown potential in reducing PCF rates in high risk patients for development of PCF such as patients undergoing TL after chemoradiation and low skeletal muscle mass (SMM). Its impact on various functional outcomes, such as shoulder and neck function, swallowing function, and voice quality, remains less explored. This study aims to investigate the effectiveness of PMMF in reducing PCF rates in patients with low SMM and its potential consequences on patient well-being. METHODS: This multicenter study adopts a randomized clinical trial (RCT) design and is funded by the Dutch Cancer Society. Eligible patients for TL, aged ≥ 18 years, mentally competent, and proficient in Dutch, will be enrolled. One hundred and twenty eight patients with low SMM will be centrally randomized to receive TL with or without PMMF, while those without low SMM will undergo standard TL. Primary outcome measurement involves assessing PCF rates within 30 days post-TL. Secondary objectives include evaluating quality of life, shoulder and neck function, swallowing function, and voice quality using standardized questionnaires and functional tests. Data will be collected through electronic patient records. DISCUSSION: This study's significance lies in its exploration of the potential benefits of using PMMF as an onlay technique during pharyngeal closure to reduce PCF rates in TL patients with low SMM. By assessing various functional outcomes, the study aims to provide a comprehensive understanding of the impact of PMMF deployment. The anticipated results will contribute valuable insights into optimizing surgical techniques to enhance patient outcomes and inform future treatment strategies for TL patients. TRIAL REGISTRATION: NL8605, registered on 11-05-2020; International Clinical Trials Registry Platform (ICTRP).

Prevalence and 3-month follow-up of cerebrovascular MRI markers in hospitalized COVID-19 patients: the CORONIS study.

PURPOSE: To investigate the prevalence of cerebrovascular MRI markers in unselected patients hospitalized for COVID-19 (Coronavirus disease 2019), we compared these with healthy controls without previous SARS-CoV-2 infection or hospitalization and subsequently, investigated longitudinal (incidental) lesions in patients after three months. METHODS: CORONIS (CORONavirus and Ischemic Stroke) was an observational cohort study in adult hospitalized patients for COVID-19 and controls without COVID-19, conducted between April 2021 and September 2022. Brain MRI was performed shortly after discharge and after 3 months. Outcomes included recent ischemic (DWI-positive) lesions, previous infarction, microbleeds, white matter hyperintensities (WMH) and intracerebral hemorrhage and were analysed with logistic regression to adjust for confounders. RESULTS: 125 patients with COVID-19 and 47 controls underwent brain MRI a median of 41.5 days after symptom onset. DWI-positive lesions were found in one patient (1%) and in one (2%) control, both clinically silent. WMH were more prevalent in patients (78%) than in controls (62%) (adjusted OR: 2.95 [95% CI: 1.07-8.57]), other cerebrovascular MRI markers did not differ. Prevalence of markers in ICU vs. non-ICU patients was similar. After three months, five patients (5%) had new cerebrovascular lesions, including DWI-positive lesions (1 patient, 1.0%), cerebral infarction (2 patients, 2.0%) and microbleeds (3 patients, 3.1%). CONCLUSION: Overall, we found no higher prevalence of cerebrovascular markers in unselected hospitalized COVID-19 patients compared to controls. The few incident DWI-lesions were most likely to be explained by risk-factors of small vessel disease. In the general hospitalized COVID-19 population, COVID-19 shows limited impact on cerebrovascular MRI markers shortly after hospitalization.

Towards retrospective motion correction and reconstruction for clinical 3D brain MRI protocols with a reference contrast.

OBJECT: In a typical MR session, several contrasts are acquired. Due to the sequential nature of the data acquisition process, the patient may experience some discomfort at some point during the session, and start moving. Hence, it is quite common to have MR sessions where some contrasts are well-resolved, while other contrasts exhibit motion artifacts. Instead of repeating the scans that are corrupted by motion, we introduce a reference-guided retrospective motion correction scheme that takes advantage of the motion-free scans, based on a generalized rigid registration routine. MATERIALS AND METHODS: We focus on various existing clinical 3D brain protocols at 1.5 Tesla MRI based on Cartesian sampling. Controlled experiments with three healthy volunteers and three levels of motion are performed. RESULTS: Radiological inspection confirms that the proposed method consistently ameliorates the corrupted scans. Furthermore, for the set of specific motion tests performed in this study, the quality indexes based on PSNR and SSIM shows only a modest decrease in correction quality as a function of motion complexity. DISCUSSION: While the results on controlled experiments are positive, future applications to patient data will ultimately clarify whether the proposed correction scheme satisfies the radiological requirements.

Differences in checkpoint-inhibitor-induced hypophysitis: mono- versus combination therapy induced hypophysitis.

Objective: Immune checkpoint inhibitors (ICIs) are revolutionary in oncology but may cause immune-related (IR) side effects, such as hypophysitis. Treatment with anti-PD-(L)1, anti-CTLA-4 or anti-CLTA-4/PD-1 may induce hypophysitis, but little is known about the differences in clinical presentation or need for different treatment. We analyzed the differences of anti-PD-(L)1, anti-CTLA-4 and anti-CTLA-4/PD-1 induced hypophysitis. Methods: retrospective analysis of 67 patients (27 anti-PD-(L)1, 6 anti-CLTA-4 and 34 anti-CTLA-4/PD-1 induced hypophysitis). Results: The median time between starting ICIs and IR-hypophysitis was longer after anti-PD(L)-1) therapy (22 weeks versus 11 and 14 weeks after anti-CTLA-4 and anti-CTLA-4/PD-1 therapy, respectively). The majority of patients (>90%), presented with atypical complaints such as fatigue, nausea, and muscle complaints. Headache, TSH or LH/FSH deficiency were more common in anti-CTLA-4 and anti-CLTA-4/PD-1 versus anti-PD-(L)1 induced hypophysitis (83% and 58% versus 8%, 67% and 41% versus 11%, and 83% and 48% versus 7%, respectively). Pituitary abnormalities on MRI (hypophysitis or secondary empty sella syndrome) were only seen in patients receiving anti-CTLA-4 or anti-CTLA-4/PD-1 therapy. Recovery from TSH, LH/FSH and ACTH deficiency was described in 92%, 70% and 0% of patients after a mean period of 14 and 104 days, respectively, and did not differ between patients who did or did not receive high-dose steroids. Conclusion: The clinical presentation of IR-hypophysitis varies depending on the type of ICIs. MRI abnormalities were only seen in anti-CTLA-4 or anti-CTLA-4/PD-1 induced hypophysitis. Endocrine recovery is seen for LH/FSH and TSH deficiency but not for ACTH deficiency, irrespective of the corticosteroid dose.

Feasibility of an MR-based digital specimen for tongue cancer resection specimens: a novel approach for margin evaluation.

Objective: This study explores the feasibility of ex-vivo high-field magnetic resonance (MR) imaging to create digital a three-dimensional (3D) representations of tongue cancer specimens, referred to as the "MR-based digital specimen" (MR-DS). The aim was to create a method to assist surgeons in identifying and localizing inadequate resection margins during surgery, a critical factor in achieving locoregional control. Methods: Fresh resection specimens of nine tongue cancer patients were imaged in a 7 Tesla small-bore MR, using a high-resolution multislice and 3D T2-weighted Turbo Spin Echo. Two independent radiologists (R1 and R2) outlined the tumor and mucosa on the MR-images whereafter the outlines were configured to an MR-DS. A color map was projected on the MR-DS, mapping the inadequate margins according to R1 and R2. We compared the hematoxylin-eosin-based digital specimen (HE-DS), which is a histopathological 3D representation derived from HE stained sections, with its corresponding MR-images. In line with conventional histopathological assessment, all digital specimens were divided into five anatomical regions (anterior, posterior, craniomedial, caudolateral and deep central). Over- and underestimation 95th-percentile Hausdorff-distances were calculated between the radiologist- and histopathologist-determined tumor outlines. The MR-DS' diagnostic accuracy for inadequate margin detection (i.e. sensitivity and specificity) was determined in two ways: with conventional histopathology and HE-DS as reference. Results: Using conventional histopathology as a reference, R1 achieved 77% sensitivity and 50% specificity, while R2 achieved 65% sensitivity and 57% specificity. When referencing to the HE-DS, R1 achieved 94% sensitivity and 61% specificity, while R2 achieved 88% sensitivity and 71% specificity. Range of over- and underestimation 95HD was 0.9 mm - 11.8 mm and 0.0 mm - 5.3 mm, respectively. Conclusion: This proof of concept for volumetric assessment of resection margins using MR-DSs, demonstrates promising potential for further development. Overall, sensitivity is higher than specificity for inadequate margin detection, because of the radiologist's tendency to overestimate tumor size.

The Differentiation between Progressive Disease and Treatment-Induced Effects with Perfusion-Weighted Arterial Spin-Labeling in High-Grade Gliomas.

BACKGROUND AND PURPOSE: Treatment-induced effects are difficult to differentiate from progressive disease in radiologically progressing diffuse gliomas after treatment. This retrospective, single-center cohort study investigated the diagnostic value of arterial spin-labeling perfusion in differentiating progressive disease from treatment-induced effects in irradiated patients with a high-grade glioma. MATERIALS AND METHODS: Adults with a high-grade glioma diagnosed between January 1, 2012, and December 31, 2018, with a new or increasing contrast-enhancing lesion after radiotherapy with or without chemotherapy and arterial spin-labeling were consecutively included. Arterial spin-labeling is part of the routine follow-up examinations of patients with a high-grade glioma. The outcomes of progressive disease or treatment-induced effects were defined after histologic or >6 weeks radiologic follow-up. Two neuroradiologists graded the arterial spin-labeling visually as negative (hypointense to gray matter) or positive (iso-/hyperintense). Additionally, the arterial spin-labeling signal intensity in the enhancing lesion was compared quantitatively with that in the contralateral normal brain. Diagnostic test properties and the Cohen κ inter- and intrarater reliability were determined. We present data according to the time after radiation therapy. RESULTS: We included 141 patients with 173 lesions (median age, 63 years). Ninety-four (54%) lesions showed treatment-induced effects, and 79 (46%), progressive disease. For visual analysis, the ORs of an arterial spin-labeling positive for progressive disease in the group with progression within 3, between 3 and 6, and after 6 months after radiation therapy were 0.65 (95% CI, 0.28-1.51; P = .319), 3.5 (95% CI, 0.69-17.89; P = .132), and 6.8 (95% CI, 1.48-32; P = .014). The areas under the curve were 0.456, 0.652, and 0.719. In quantitative analysis, the areas under the curve were 0.520, 0.588, and 0.587 in these groups. Inter- and intrarater reliability coefficients were 0.67 and 0.62. CONCLUSIONS: Arterial spin-labeling performed poorly in differentiating progressive disease from treatment-induced effects in high-grade gliomas within 6 months after radiation therapy, with fair performance after this period. Arterial spin-labeling may need to be combined with other imaging features and clinical information for better performance.

The Additional Value of Somatostatin Receptor Positron Emission Computed Tomography ([68Ga]Ga-DOTATOC PET/CT) Compared with Magnetic Resonance Imaging of the Head and Neck Region in Paraganglioma Patients: A Pilot Study.

The Dutch guideline for patients suspected of head and neck paragangliomas (HNPGLs) recommends magnetic resonance imaging (MRI) and/or computed tomography (CT) of the head and neck area. Additionally, it suggests considering additional nuclear imaging. The aim of this study was to evaluate the outcomes of [68Ga]Ga-DOTATOC PET/CT compared to MRI in patients with suspected HNPGLs and carriers of genetic variations. METHODS: In this single-center pilot study, retrospective data were obtained from consecutive patients between 2016 and 2023. Both MRI and [68Ga]Ga-DOTATOC PET/CT were performed within 12 months. The primary outcome was the location of HNPGLs. RESULTS: A total of 25 consecutive patients were included, and 7 patients (28.0%, p = 0.5) showed differences between the imaging modalities, of whom 5 patients had unexpected localizations with additional uptake by somatostatin receptors (SSTR) on the [68Ga]Ga-DOTATOC PET/CT. CONCLUSIONS: The authors recommend performing baseline imaging with [68Ga]Ga-DOTATOC PET/CT (if available) in variant carriers and using MRI/CT for follow-up according to the regional protocol, thereby shifting the gold standard for baseline imaging from MRI/CT to [68Ga]Ga-DOTATOC PET/CT.