Innovative Use of an Injectable, Self-Healing Drug-Loaded Pectin-Based Hydrogel for Micro- and Supermicro-Vascular Anastomoses.

Microvascular surgery plays a crucial role in reconnecting micrometer-scale vessel ends. Suturing remains the gold standard technique for small vessels; however, suturing the collapsed lumen of microvessels is challenging and time-consuming, with the risk of misplaced sutures leading to failure. Although multiple solutions have been reported, the emphasis has predominantly been on resolving challenges related to arteries rather than veins, and none has proven superior. In this study, we introduce an innovative solution to address these challenges through the development of an injectable lidocaine-loaded pectin hydrogel by using computational and experimental methods. To understand the extent of interactions between the drug and the pectin chain, molecular dynamics (MD) simulations and quantum mechanics (QM) calculations were conducted in the first step of the research. Then, a series of experimental studies were designed to prepare lidocaine-loaded injectable pectin-based hydrogels, and their characterization was performed by using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and rheological analysis. After all the results were evaluated, the drug-loaded pectin-based hydrogel exhibiting self-healing properties was selected as a potential candidate for in vivo studies to determine its performance during operation. In this context, the hydrogel was injected into the divided vessel ends and perivascular area, allowing for direct suturing through the gel matrix. While our hydrogel effectively prevented vasospasm and facilitated micro- and supermicro-vascular anastomoses, it was noted that it did not cause significant changes in late-stage imaging and histopathological analysis up to 6 months. We strongly believe that pectin-based hydrogel potentially enhanced microlevel arterial, lymphatic, and particularly venous anastomoses.

Dynamic (live) 3D roadmap as navigational tool in multiplug brain arteriovenous malformation embolization: technical note.

PURPOSE: Treatment of brain arteriovenous malformation (bAVM) includes microsurgical excision, stereotactic radiosurgery, endovascular embolization, or combination. With bAVM embolization, complete angiographic obliteration ranges from 12.5 to 51%, and higher total occlusion rate is seen in SM grades I to III, ranging from 96 to 100%. METHODS: In this paper, we illustrate the use of 3D rotational angiography and dynamic (live) 3D roadmap functions in endovascular treatment of bAVM. A single dynamic 3D roadmap or two dynamic 3D roadmaps obtained help tremendously in navigation of microcatheters and wires along the parent artery and bAVM feeders. RESULTS: This method eliminates the need for repeated 2D angiograms and roadmaps for new working projections every time the C-arm position is changed for cannulation of different feeders, thereby reducing radiation dose. No instances of misalignment error, vascular perforation, or thromboembolic phenomena were observed in the 21 embolization cases performed within the previous 2 years while utilizing this feature. CONCLUSION: The dynamic 3D roadmap is an extremely useful tool for multiple-feeder cannulation, by reducing the use of multiple 2D angiograms, providing intraprocedural live and adjustable 3D roadmap for better mental orientation to angioarchitecture of the bAVM, which further aids in the overall complete angiographic obliteration rate of bAVM in a single session especially in multiplug embolization technique.

Comparison of MRI findings of hypothalamic-optic chiasmatic gliomas and craniopharyngiomas.

BACKGROUND: Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging. PURPOSE: To compare the MRI features of HOCGs and cranipharyngiomas. MATERIAL AND METHODS: Patients diagnosed with HOCG or craniopharyngioma in histopathological evaluation between 2012 and 2022 and who underwent preoperative contrast-enhanced brain MRI were included. Various MRI features were retrospectively evaluated for each lesion: T2-weighted imaging and fluid attenuation inversion recovery hyperintensity, calcification, cystic change, T1-weighted (T1W) imaging hyperintensity of the cystic component, hemorrhage, involvement of sellar, suprasellar or other adjacent structures, lobulated appearance, presence of hydrocephalus, and contrast enhancement pattern. Apparent diffusion coefficient (ADC) values were also evaluated and compared. RESULTS: Among 38 patients included, 13 (34%) had HOCG and 25 (66%) had craniopharyngioma. Craniopharyngiomas had a significantly higher rate of cystic changes, calcification, and T1W imaging hyperintensity of the cystic component than HOCGs (P <0.05). Of HOCGs, 92% had chiasm involvement, 23% had optic nerve involvement, and 31% had brain stem involvement. On the other hand, chiasm involvement was observed in 8% of craniopharyngiomas, but none had optic nerve and/or brain stem involvement (P <0.05). While 62% (8/13) of HOCGs had diffuse homogeneous enhancement, 80% (20/25) of craniopharyngiomas had a diffuse heterogeneous enhancement pattern. Mean ADC values were significantly higher in craniopharyngiomas compared to HOCGs (2.1 vs. 1.6 ×10-3mm2/s, P <0.05). CONCLUSION: Although some neuroimaging findings may overlap, features such as presence of cyst and calcification, brain stem and optic pathway involvement, different enhancement patterns, and ADC values may be helpful in the differential diagnosis of HOCGs and craniopharyngiomas.

Assessment of myelin oligodendrocyte glycoprotein antibodies and magnetic resonance spectroscopy in childhood-onset systemic lupus erythematosus.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterised by the presence of various autoantibodies. Mild cognitive impairment developing in patients without significant neuropsychiatric (NP) symptoms was thought to be the result of immune-mediated myelinopathy. We aimed to determine the role of myelin oligodendrocyte glycoprotein antibody (MOG-Ab) in the neurological manifestations of childhood-onset SLE (cSLE) and if there is a correlation between various metabolite peaks in magnetic resonance spectroscopy (MRS) and myelinopathy. METHODS: MOG-Ab levels were studied in all healthy subjects (n=28) and in all patients with (NPSLE=9) and without (non-NPSLE=36) overt neuropsychiatric manifestations. Twenty patients (all had a normal-appearing brain on plain magnetic resonance) in non-NPSLE and 20 subjects in healthy group met the MRS imaging standards for evaluation in which normal appearing brain on plain MR. RESULTS: A total of 45 cSLE (36 non-NPSLE and 9 NPSLE) subjects and 28 healthy children were recruited to the study. The mean age of the SLE patients at study time was 16.22±3.22 years. MOG-Ab was not detected in cSLE or in healthy group. There was no significant difference between the non-NPSLE group and healthy subjects in terms of choline, N-acetyl aspartate (NAA), creatine, NAA/creatine, and choline/creatine. CONCLUSIONS: There was no association of MOG-Ab with cSLE, whether NP manifestations were present or not. A causal relationship between immune-mediated myelinopathy and cognitive impairment could not be suggested, since there has been no patient with positive MOG-Ab and there has been no difference in choline, choline/creatine between groups.

Evaluation of short- and long-term results of Y-stent-assisted coiling with Leo stents in endovascular treatment of wide-necked intracranial bifurcation aneurysms.

PURPOSE: This study aimed to evaluate the feasibility, safety, and efficacy of Y-stent-assisted coiling (Y-SAC) using LEO Baby® stents in treating of bifurcation aneurysms. METHODS: Patients who underwent Y-SAC using a braided stent (LEO Baby®, Montmorency, France) for wide-necked intracranial aneurysms between 2009 and 2019 and whose radiological and clinical follow-up data for at least 6 months could be obtained were evaluated. Data were obtained from patient records and analyzed retrospectively. RESULTS: We evaluated 111 patients with a mean age of 56.0 ± 10.8 years (range, 25-88 years). Most of the aneurysms were detected incidentally. Three patients had ruptured aneurysms. LEO Baby deployment and coiling were successful in all patients. Immediate aneurysm occlusion rates were determined as modified Raymond-Roy classification (mRRC) I 95.5% (n = 106), mRRC II 3.6% (n = 4), mRRC IIIa 0.9% (n = 1). In the sixth month, aneurysm occlusion rates were found to be complete and nearly complete in all patients (mRRC I 94.6%, n = 105 and mRRC II 4.5%; n = 5, respectively). Follow-up data of 91 patients for > 2 years were obtained. Of these, 88 had MRRCI obstruction and 3 had MRRC II obstruction. The overall complication rate was 4.8%, and one patient died during the post-procedural follow-up. CONCLUSION: The long-term follow-up results of Y-stenting with LEO Baby revealed that it provides stable closure of the aneurysm sac while preserving the main arterial structures. Therefore, it is a safe, durable, and effective method for treating wide-necked and complex bifurcation aneurysms.

Spontaneous internal carotid artery dissection in a child diagnosed by high resolution vessel wall MRI.

Craniocervical dissection is one of the most common causes of stroke in children. Although the most common cause of dissection is trauma, spontaneous dissections in which no cause can be revealed may also occur. The diagnosis of this type of dissection in children can be challenging with the preferred non-invasive imaging methods (MRA, CTA). Intracranial vessel wall imaging is a promising novel method for identifying specific signs of dissection. We report an 11-year-old girl with spontaneous ICA dissection, whose diagnosis was confirmed by an MRI of the intracranial vessel wall. Vessel wall imaging has contributed substantially to the diagnosis and follow-up of this case.

The efficacy of preoperative diffusion tensor tractography on surgical planning and outcomes in patients with intramedullary spinal tumor.

PURPOSE: The aim of this study was to investigate the efficacy of diffusion tensor tractography (DTT) of spinal cord on surgical planning and postoperative neurological outcomes in patients with spinal intramedullary tumors. METHODS: The study was conducted retrospectively from the radiological and clinical data of our hospital database. Patients with intramedullary spinal cord tumors who underwent diffusion tensor imaging for spinal cord lesions were selected between 2019 and 2022. Demographic characteristics and intraoperative neurophysiological monitoring data were evaluated. The McCormick scale was used to grade the pre- and postoperative neurological status of the patients. The tumoral lesions were categorized into 3 types according to the fiber course on DTT. RESULTS: Eleven patients were found to have radiological findings that were compatible with intramedullary tumor; eight (72.7%) of them ultimately underwent surgery following being approved as surgical candidates in the spinal diffusion tensor imaging studies. Six cases had Type 1, one case had Type 2, and 4 cases had Type 3 tumors according to the fiber course. All Type 1 tumors were classified as resectable and all of them were gross totally resected. Type 2 lesion that was rated as resectable by DTI was subtotally resected. Type 3 lesions were followed without surgery except the one with tumoral progression and neurological deficit. The postoperative neurological outcomes were compatible with intraoperative neurophysiological monitoring results. CONCLUSION: Diffusion tensor imaging and tractography may be beneficial regarding the selection of patients suitable for surgery and in the subsequent surgical planning.

A new ventricular index based on coronal brain magnetic resonance images in patients with idiopathic normal pressure hydrocephalus.

BACKGROUND: The aim of this study was to assess the effectiveness of a new quantitative index for the diagnosis of idiopathic normal pressure hydrocephalus. METHODS: This retrospective study was conducted at Istanbul University Cerrahpasa Medical Faculty between January 2016 and November 2022. A total of 31 patients diagnosed with idiopathic normal pressure hydrocephalus were included in the study group and 48 patients were included in the control group. Measurement via the new Index was performed on a coronal section of magnetic resonance imaging at the level of the anterior commissure. RESULTS: The new Index's mean diagnostic performance was 1.16 ± 0.08 in the study group, significantly lower (p < 0.0001) than the mean of 1.43 ± 0.10 in the control group. When a cutoff value of 1.23 was used for the new index, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates were 96.1%, 90.7%, 80.6%, 98%, and 91.3%, respectively. DISCUSSION: The new Index described here is an effective, feasible, reproducible, highly sensitive, and specific quantitative method that can contribute to the improved diagnosis of patients with idiopathic normal pressure hydrocephalus.

Machine learning as a clinical decision support tool for patients with acromegaly.

OBJECTIVE: To develop machine learning (ML) models that predict postoperative remission, remission at last visit, and resistance to somatostatin receptor ligands (SRL) in patients with acromegaly and to determine the clinical features associated with the prognosis. METHODS: We studied outcomes using the area under the receiver operating characteristics (AUROC) values, which were reported as the performance metric. To determine the importance of each feature and easy interpretation, Shapley Additive explanations (SHAP) values, which help explain the outputs of ML models, are used. RESULTS: One-hundred fifty-two patients with acromegaly were included in the final analysis. The mean AUROC values resulting from 100 independent replications were 0.728 for postoperative 3 months remission status classification, 0.879 for remission at last visit classification, and 0.753 for SRL resistance status classification. Extreme gradient boosting model demonstrated that preoperative growth hormone (GH) level, age at operation, and preoperative tumor size were the most important predictors for early remission; resistance to SRL and preoperative tumor size represented the most important predictors of remission at last visit, and postoperative 3-month insulin-like growth factor 1 (IGF1) and GH levels (random and nadir) together with the sparsely granulated somatotroph adenoma subtype served as the most important predictors of SRL resistance. CONCLUSIONS: ML models may serve as valuable tools in the prediction of remission and SRL resistance.

Discrimination between non-functioning pituitary adenomas and hypophysitis using machine learning methods based on magnetic resonance imaging­derived texture features.

PURPOSE: Hypophysitis is a heterogeneous condition that includes inflammation of the pituitary gland and infundibulum, and it can cause symptoms related to mass effects and hormonal deficiencies. We aimed to evaluate the potential role of machine learning methods in differentiating hypophysitis from non-functioning pituitary adenomas. METHODS: The radiomic parameters obtained from T1A-C images were used. Among the radiomic parameters, parameters capable of distinguishing between hypophysitis and non-functioning pituitary adenomas were selected. In order to avoid the effects of confounding factors and to improve the performance of the classifiers, parameters with high correlation with each other were eliminated. Machine learning algorithms were performed with the combination of gray-level run-length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray-level co-occurrence entropy. RESULTS: A total of 34 patients were included, 17 of whom had hypophysitis and 17 had non-functioning pituitary adenomas. Among the 38 radiomics parameters obtained from post-contrast T1-weighted images, 10 tissue features that could differentiate the lesions were selected. Machine learning algorithms were performed using three selected parameters; gray level run length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray level co-occurrence entropy. Error matrices were calculated by using the machine learning algorithm and it was seen that support vector machines showed the best performance in distinguishing the two lesion types. CONCLUSIONS: Our analysis reported that support vector machines showed the best performance in distinguishing hypophysitis from non-functioning pituitary adenomas, emphasizing the importance of machine learning in differentiating the two lesions.

Trigeminal neuropathy as presenting symptom of craniofacial venous metameric syndrome.

AIMS: Trigeminal neuropathy is more likely to suggest neuronal damage and occur due to secondary pathology than trigeminal neuralgia. Evaluation of underlying etiologies are necessary. CASE: A 29-year-old female patient presented with left sided continuous burning pain likened to pins and needles at maxillary distribution for about a year. Her examination was normal except left-sided buccal swelling without any skin or mucosal change. Cranial MRI revealed asymmetrical dilation of left Meckel's cave, bilateral cerebral developmental venous anomaly and left sided slow flow venous malformation from superior temporal fossa to masseter muscle. Cerebral angiography confirmed widespread venous return anomaly in both cerebral hemispheres and slow-flow venous malformation that does not fill in the early arterial phase in the left buccal space and superficial temporal fossa. Cerebrofacial venous metameric syndrome is diagnosed. Percutaneous sclerotherapy with alcohol is planned in three separate sessions, the first of the three planned sessions is performed yet and the patient stated that her neuropathic pain decreased by 40% afterwards. SIGNIFICANCE: Clinical manifestation of the cerebrofacial venous metameric syndrome depends on the localization of the lesions; therefore, venous anomalies in relation with the trigeminal branches can present with painful trigeminal neuropathy.

Intracranial vessel wall imaging.

PURPOSE OF REVIEW: To give an overview regarding the potential usefulness of vessel wall imaging (VWI) in distinguishing various intracranial vascular diseases, their common imaging features, and potential pitfalls. RECENT FINDINGS: VWI provides direct visualization of the vessel wall and allows the discrimination of different diseases such as vasculitis, atherosclerosis, dissection, Moyamoya disease, and reversible cerebral vasoconstriction syndrome. Recent studies showed that concentric and eccentric involvement in the vessel wall, as well as the enhancement pattern were found important for the distinguishing these diseases and evaluating their activity. SUMMARY: Most of the imaging techniques currently used are based on luminal imaging. However, these imaging methods are not adequate to distinguish different diseases that can demonstrate similar radiological findings. VWI is being increasingly used as a noninvasive imaging method to offset this limitation.

The diagnostic contribution of intracranial vessel wall imaging in the differentiation of primary angiitis of the central nervous system from other intracranial vasculopathies.

PURPOSE: The aim of this study is to demonstrate the diagnostic effect of VWI in differentiating PACNS from other vasculopathies and its role in post-treatment follow-up in PACNS patients in this study. METHODS: In this prospective study, we included patients with clinical suspicion of PACNS who presented with new-onset ischemic events and had significant intracranial large vessel stenosis on DSA or MRA. VWI was performed on all patients. The imaging findings and final diagnoses were recorded. Control VWI was performed on patients with PACNS diagnosis after at least 3 months of treatment, and the change in findings was also evaluated. RESULTS: Twenty-three patients were included in the study had a median age of 40 (range 12-58). The most common clinical manifestations were focal neurologic deficits. According to the initial clinical evaluation, 10 patients (43.5%) were classified as PACNS and 13 patients (56.5%) as indeterminate for PACNS. After incorporating the VWI findings, the diagnosis of PACNS was confirmed in all clinically diagnosed PACNS patients. Concentric wall thickening and contrast enhancement were statistically significant in the PACNS group (p <0.001). According to concentric thickening and VWE features, sensitivity and specificity in distinguishing PACNS and other vasculopathies were 95.2%, 75% and 95.2%, 68.8%, respectively. Vessel wall enhancement regressed in 7 of 9 patients during a median follow-up period of 8 months (range 5.5-11.5) in PACNS patients who followed up. CONCLUSION: VWI seems a new and useful imaging method in the differential diagnosis of PACNS and might be a useful adjunct for post-treatment follow-up.

Endovascular treatment of anterior cranial fossa dural arteriovenous fistula: a multicenter series.

PURPOSE: We report a multicenter experience using endovascular embolization as the first line approach for treatment of anterior cranial fossa (ACF) dural arteriovenous fistula (DAVF). METHODS: All patients with DAVFs located in the anterior cranial fossa who were treated with endovascular technique as a first line approach were included. Demographics, clinical presentation, angioarchitecture, strategy, complications, immediate angiographic, and follow-up results were included in the analysis. RESULTS: Twenty-three patients met the inclusion criteria (18 male and 5 female). Age ranged from 14 to 79 years (mean 53 years). Twelve patients presented with hemorrhage. Twenty-eight endovascular procedures were performed. The overall immediate angiographic cure rate after endovascular treatment was 82.6% (19/23 patients). The angiographic cure rate of the transvenous strategy was significantly superior to the transarterial strategy (p ≤ 0.001). There was 1 complication in 28 total procedures (3.6%). Angiographic follow-up was available in 21 out of the 23 patients with a mean of 25 months (range 2 to 108 months). In these 21 patients, the DAVF was completely cured in 20 (95%). At last follow-up, all patients had a modified Rankin scale (mRS) 0 to 2. CONCLUSION: Our experience suggests that endovascular treatment for ACF DAVFs has an acceptable safety profile with high rates of complete occlusion, particularly with transvenous approach. Whenever possible, transvenous approach should be preferred over transarterial approach as first line strategy.

Does measurement of the jugular foramen diameter on MRI help to differentiate transverse sinus thrombosis from unilateral transverse sinus hypoplasia?

BACKGROUND AND PURPOSE: The transverse sinus (TS) is a frequent location of cerebral venous thrombosis. However, unilateral TS hypoplasia is a frequent variation and radiological imaging pitfall in the diagnosis because it may mimic unilateral TS thrombosis. The purpose of this study is to find a cutoff value for bilateral jugular foramen (JF) diameter ratios on magnetic resonance imaging (MRI) for differentiating TS thrombosis from TS hypoplasia. MATERIALS AND METHODS: We retrospectively reviewed magnetic resonance venography results for 174 patients with reduced unilateral TS caliber resulting from either unilateral thrombosis (80 patients) or unilateral hypoplasia (94 patients). We calculated the ratio by proportioning the diameter of the JF ipsilateral to the TS with caliber reduction to the diameter of the contralateral JF. The Mann-Whitney U test was used to compare the ratios between thrombosis and hypoplasia groups, and the cutoff value was calculated by receiver-operating characteristic curve analysis. RESULTS: The ratio of bilateral JF diameters was lower in patients with hypoplasia than those with thrombosis (P < .01). The cutoff value to determine the diagnosis of TS hypoplasia with maximum accuracy was 0.638, with a sensitivity of 91.3% and specificity of 64.9%. CONCLUSION: In equivocal cases, calculating the cutoff value by proportioning the diameter of JF ipsilateral to the TS with caliber reduction to the contralateral JF seems to be an efficient, quick, and straightforward method and valuable aid to differentiate TS thrombosis from TS hypoplasia.

Brain MRI Findings in Patients in the Intensive Care Unit with COVID-19 Infection.

Online supplemental material is available for this article.

Intrathecal use of gadobutrol for gadolinium-enhanced MR cisternography in the evaluation of patients with otorhinorrhea.

PURPOSE: Intrathecal gadolinium-enhanced MR cisternography (IGE-MRC) has a high sensitivity to detect accurate localization of cerebrospinal fluid (CSF) leakage in otorhinorrhea patients. Our purpose in this study was to describe our experience in analyzing clinically suspected CSF leakage by IGE-MRC by using gadobutrol with emphasis on its safety and diagnostic performance. METHODS: We retrospectively reviewed our imaging and clinical database for the evaluation of patients admitted to our clinic with complaints of otorhinorrhea between 2017 and 2019. Two radiologists evaluated the imaging studies independently. Consensus data was used in the analysis. Medical record review and phone call were used for the follow-up. RESULTS: Of the 85 patients included in the retrospective analysis, 82 (96.5%) had rhinorrhea and 3 (3.5%) had otorrhea. Overall, 29 patients (34.1% of all patients) underwent operation for repair of the CSF leakage site. Beta-transferrin test was available and positive in 33 patients (38.8%). Five (5.9%) patients complained headaches after the procedure and complaints were resolved with increased water intake. Postprocedurally, 3 patients (3.5%) had vertigo and 1 patient (1.2%) complained nausea but spontaneous regression were observed in a few hours. None of the patients experienced a significant complication or adverse reaction during follow-up period. Sixty-seven patients (78.8%) had medical record and telephone follow-up. Mean follow-up duration with call was 14.2 months. CONCLUSION: IGE-MRC is a minimally invasive and highly sensitive imaging technique. The current results during our follow-up demonstrate the relative safety and feasibility of IGE-MRC by using gadobutrol to evaluate CSF leakage.

Evaluation of sporadic intracranial cavernous malformations for detecting associated developmental venous anomalies: added diagnostic value of C-arm contrast-enhanced cone-beam CT to routine contrast-enhanced MRI.

OBJECTIVE: Our purpose was to investigate the added diagnostic value of C-arm contrast-enhanced cone-beam CT (CE-CBCT) to routine contrast-enhanced MRI (CE-MRI) in detecting associated developmental venous anomalies (DVAs) in patients with sporadic intracranial cavernous malformations (ICMs). METHODS: Fifty-six patients (53 with single and three with double ICMs) met the inclusion criteria. All patients had routine CE-MRI scans performed at 1.5 Tesla. The imaging studies (CE-MRI and CE-CBCT) were retrospectively and independently reviewed by two observers, with consensus by a third. Group difference, intra- and interobserver agreement, and diagnostic performance of the modalities in detecting associated DVAs were calculated. Reference standard was CE-MRI. RESULTS: On CE-MRI and CE-CBCT, 37 (66%; of 56) and 47 patients (84%; of 56) had associated DVAs, respectively. In 10 patients (52.6%; of CE-MRI negatives [n=19]), CE-CBCT improved the diagnosis. Nine patients (16%; of 56) had no DVA on both imaging techniques. Difference in proportions of associated DVAs on CE-MRI and CE-CBCT was statistically significant, p < 0.05. Sensitivity, specificity, positive likelihood ratio, and area under the curve of CE-CBCT were 100% (95% confidence interval [CI]: 90.5-100%), 47.3% (95% CI: 24.4-71.1%), 1.9 (95%CI: 1.240-2.911), 0.737 (95%CI: 0.602-0.845), respectively. Intraobserver agreement was excellent for CE-MRI, kappa (κ) coefficient = 0.960, and CE-CBCT, κ=0.931. Interobserver agreement was substantial for CE-MRI, κ=0.803, and excellent for CE-CBCT, κ=0.810. CONCLUSIONS: CE-CBCT is a useful imaging technique especially in patients with negative routine CE-MRI in terms of detecting associated DVAs. In nearly half of these particular patients, it reveals an associated DVA as a new diagnosis. KEY POINTS: • Although it is known to be the gold standard, some of the DVAs associated with ICMs are underdiagnosed with CE-MRI. • In nearly half of the patients with negative routine CE-MRI, CE-CBCT reveals an associated DVA as a new diagnosis. • Intra- and interobserver agreement on CE-CBCT is excellent in terms of detecting associated DVAs.

Predicting response to somatostatin analogues in acromegaly: machine learning-based high-dimensional quantitative texture analysis on T2-weighted MRI.

OBJECTIVE: To investigate the value of machine learning (ML)-based high-dimensional quantitative texture analysis (qTA) on T2-weighted magnetic resonance imaging (MRI) in predicting response to somatostatin analogues (SA) in acromegaly patients with growth hormone (GH)-secreting pituitary macroadenoma, and to compare the qTA with quantitative and qualitative T2-weighted relative signal intensity (rSI) and immunohistochemical evaluation. METHODS: Forty-seven patients (24 responsive; 23 resistant patients to SA) were eligible for this retrospective study. Coronal T2-weighted images were used for qTA and rSI evaluation. The immunohistochemical evaluation was based on the granulation pattern of the adenomas. Dimension reduction was carried out by reproducibility analysis and wrapper-based algorithm. ML classifiers were k-nearest neighbours (k-NN) and C4.5 algorithm. The reference standard was the biochemical response status. Predictive performance of qTA was compared with those of the quantitative and qualitative rSI and immunohistochemical evaluation. RESULTS: Five hundred thirty-five out of 828 texture features had excellent reproducibility. For the qTA, k-NN correctly classified 85.1% of the macroadenomas regarding response to SAs with an area under the receiver operating characteristic curve (AUC-ROC) of 0.847. The accuracy and AUC-ROC ranges of the other methods were 57.4-70.2% and 0.575-0.704, respectively. Differences in predictive performance between qTA-based classification and the other methods were significant (p < 0.05). CONCLUSIONS: The ML-based qTA of T2-weighted MRI is a potential non-invasive tool in predicting response to SAs in patients with acromegaly and GH-secreting pituitary macroadenoma. The method performed better than the qualitative and quantitative rSI and immunohistochemical evaluation. KEY POINTS: • Machine learning-based texture analysis of T2-weighted MRI can correctly classify response to somatostatin analogues in more than four fifths of the patients. • Machine learning-based texture analysis performs better than qualitative and quantitative evaluation of relative T2 signal intensity and immunohistochemical evaluation. • About one third of the texture features may not be excellently reproducible, indicating that a reliability analysis is necessary before model development.

Preoperative evaluation of tumour consistency in pituitary macroadenomas: a machine learning-based histogram analysis on conventional T2-weighted MRI.

PURPOSE: To evaluate the potential value of machine learning (ML)-based histogram analysis (or first-order texture analysis) on T2-weighted magnetic resonance imaging (MRI) for predicting consistency of pituitary macroadenomas (PMA) and to compare it with that of signal intensity ratio (SIR) evaluation. METHODS: Fifty-five patients with 13 hard and 42 soft PMAs were included in this retrospective study. Histogram features were extracted from coronal T2-weighted original, filtered and transformed MRI images by manual segmentation. To achieve balanced classes (38 hard vs 42 soft), multiple samples were obtained from different slices of the PMAs with hard consistency. Dimension reduction was done with reproducibility analysis, collinearity analysis and feature selection. ML classifier was artificial neural network (ANN). Reference standard for the classifications was based on surgical and histopathological findings. Predictive performance of histogram analysis was compared with that of SIR evaluation. The main metric for comparisons was the area under the receiver operating characteristic curve (AUC). RESULTS: Only 137 of 162 features had excellent reproducibility. Collinearity analysis yielded 20 features. Feature selection algorithm provided six texture features. For histogram analysis, the ANN correctly classified 72.5% of the PMAs regarding consistency with an AUC value of 0.710. For SIR evaluation, accuracy and AUC values were 74.5% and 0.551, respectively. Considering AUC values, ML-based histogram analysis performed better than SIR evaluation (z = 2.312, p = 0.021). CONCLUSION: ML-based T2-weighted MRI histogram analysis might be a useful technique in predicting the consistency of PMAs, with a better predictive performance than that of SIR evaluation.