Burak Kocak

Endovascular treatment of carotid cavernous sinus fistula: A systematic review

Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial work-up of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions.

Use of Buddy Wire to Facilitate Y-Configured Stent Placement in Middle Cerebral Artery Bifurcation Aneurysms With Daughter Branches Arising From the Sac: A Technical Note

BACKGROUND AND IMPORTANCE: Endovascular treatment of geometrically complex bifurcation aneurysms using a standard Y-configured stenting technique might be extremely difficult, particularly in aneurysms with daughter branches that acutely arise from the aneurysm sac itself. In those cases, deployment of the second stent through interstices of the first stent could be troublesome because of untoward angular changes in the vascular bifurcation prompted by angular changes resulting from placement of the first stent. Here, we describe a novel application of the buddy wire technique to facilitate Y-configured stenting in middle cerebral artery (MCA) bifurcation aneurysms with unfavorable anatomic configuration. CLINICAL PRESENTATION: A 60-year-old man with a left-sided MCA bifurcation aneurysm was treated using the buddy wire technique. In addition to the standard Y-configured stenting procedure, we also inserted a 0.014-inch exchange microguidewire into the superior daughter branch, which more acutely emanated from the sac, to attain a favorable bifurcation configuration before deployment of the stents in the Y configuration. The new technique was successful, and the postprocedural course of the treatment was uneventful. CONCLUSION: Use of a buddy wire in MCA bifurcation aneurysms with unfavorable anatomic configurations may be a promising method to facilitate Y-configured stent placement. ABBREVIATION: MCA, middle cerebral artery

Total agenesis of superior sagittal sinus and falx cerebri in a patient who has a subacute subdural hematoma crossing midline: case report.

BACKGROUND AND IMPORTANCE Anatomic variations of the superior sagittal sinus (SSS) and falx cerebri (FC) are uncommon in that agenesis of these structures is extremely rare. We report an extremely rare anatomic variation, total agenesis of the SSS and FC, and briefly discuss it from the anatomical, embryological, radiological, and clinical perspectives. CLINICAL PRESENTATION A 49-year-old woman presented with long-standing headache, gait disturbance, and nausea. Imaging studies showed a bilateral subdural hematoma crossing the midline, dilated venous structures, and perineural cysts, but SSS and FC. Following right-sided hemiparesis and consciousness disturbances, the subdural hematoma was evacuated from a left-sided parietal burr hole because of thick hematoma in this side. After the surgical evacuation, the hemiparesis and consciousness disturbances were regressed; however, she still had severe headache. On account of ongoing headaches and related imaging findings, it was thought that she had possible spontaneous intracranial hypotension. She was treated with autologous epidural blood patch and recovered well. CONCLUSION Agenesis of the SSS and FC are extremely rare variations. Agenesis of the SSS results in development of alternative venous pathways and may lead to misdiagnosis as dural arteriovenous fistulas. Agenesis of FC may cause diagnostic confusion, because subdural pathologies such as hematomas can cross the midline in rare occasions.

Dissecting aneurysms of posterior communicating artery itself: anatomical, diagnostic, clinical, and therapeutical considerations

Posterior communicating artery (PCoA) itself is an unusual location for intracranial aneurysms in that isolated dissections or dissecting aneurysms are extremely rare. In the way of correct diagnosis of dissecting aneurysms of PCoA itself, a proper understanding of (1) the anatomy of the PCoA and its perforator branches, (2) some particular diagnostic features, and (3) related clinical aspects is of significant importance. Although there are no established treatment strategies for this particular type of aneurysms, the endovascular approach might be considered as a plausible one. In this paper, our scope was to report five cases with dissecting aneurysm of the PCoA itself and to discuss this rare vascular pathology from anatomical, diagnostic, clinical, and therapeutical perspectives.

Carotid stenting with low-dose contrast medium for patients with moderate-to-severe chronic renal insufficiency: Keyhole carotid stenting

Herein, we describe a new carotid stenting approach for four patients with moderate-to-severe chronic renal insufficiency, who have a glomerular filtration rate (GFR) between 15 and 59 mL/min/1.73 m(2), using a minimum dose of contrast medium (12 mL at a 50% dilution) and SmartMask™ technology as an alternative to carotid endarterectomy.

Regional anesthesia with epinephrine-containing lidocaine reduces pericatheter bleeding after tunneled hemodialysis catheter placement: Pericatheter bleeding

Introduction: Pericatheter bleeding (PB) following tunneled hemodialysis catheter (THC) placement is a common phenomenon. In addition to complicating securement of the THC, the PB may loosen the adhesive catheter dressing and delay wound healing. The primary aim of this study was to determine whether epinephrine‐containing local anesthetics rather than plain ones reduce superficial PB after THC placement.

Clear Cell Renal Cell Carcinoma: Machine Learning-Based Quantitative Computed Tomography Texture Analysis for Prediction of Fuhrman Nuclear Grade

ObjectiveTo evaluate the performance of quantitative computed tomography (CT) texture analysis using different machine learning (ML) classifiers for discriminating low and high nuclear grade clear cell renal cell carcinomas (cc-RCCs).Materials and methodsThis retrospective study included 53 patients with pathologically proven 54 cc-RCCs (31 low-grade [grade 1 or 2]; 23 high-grade [grade 3 or 4]). In one patient, two synchronous cc-RCCs were included in the analysis. Mean age was 57.5 years. Thirty-four (64.1%) patients were male and 19 were female (35.9%). Mean tumour size based on the maximum diameter was 57.4 mm (range, 16–145 mm). Forty patients underwent radical nephrectomy and 13 underwent partial nephrectomy. Following pre-processing steps, two-dimensional CT texture features were extracted using portal-phase contrast-enhanced CT. Reproducibility of texture features was assessed with the intra-class correlation coefficient (ICC). Nested cross-validation with a wrapper-based algorithm was used in feature selection and model optimisation. The ML classifiers were support vector machine (SVM), multilayer perceptron (MLP, a sort of neural network), naïve Bayes, k-nearest neighbours, and random forest. The performance of the classifiers was compared by certain metrics.ResultsAmong 279 texture features, 241 features with an ICC equal to or higher than 0.80 (excellent reproducibility) were included in the further feature selection process. The best model was created using SVM. The selected subset of features for SVM included five co-occurrence matrix (ICC range, 0.885–0.998), three run-length matrix (ICC range, 0.889–0.992), one gradient (ICC = 0.998), and four Haar wavelet features (ICC range, 0.941–0.997). The overall accuracy, sensitivity (for detecting high-grade cc-RCCs), specificity (for detecting high-grade cc-RCCs), and overall area under the curve of the best model were 85.1%, 91.3%, 80.6%, and 0.860, respectively.ConclusionsThe ML-based CT texture analysis can be a useful and promising non-invasive method for prediction of low and high Fuhrman nuclear grade cc-RCCs.Key Points• Based on the percutaneous biopsy literature, ML-based CT texture analysis has a comparable predictive performance with percutaneous biopsy.• Highest predictive performance was obtained with use of the SVM.• SVM correctly classified 85.1% of cc-RCCs in terms of nuclear grade, with an AUC of 0.860.

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

ObjectiveOur 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).MethodsFifty-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.ResultsOn 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.ConclusionsCE-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.

Textural differences between renal cell carcinoma subtypes: Machine learning-based quantitative computed tomography texture analysis with independent external validation

OBJECTIVE To develop externally validated, reproducible, and generalizable models for distinguishing three major subtypes of renal cell carcinomas (RCCs) using machine learning-based quantitative computed tomography (CT) texture analysis (qCT-TA). MATERIALS AND METHODS Sixty-eight RCCs were included in this retrospective study for model development and internal validation. Another 26 RCCs were included from public databases (The Cancer Genome Atlas-TCGA) for independent external validation. Following image preparation steps (reconstruction, resampling, normalization, and discretization), 275 texture features were extracted from unenhanced and corticomedullary phase CT images. Feature selection was firstly done with reproducibility analysis by three radiologists, and; then, with a wrapper-based classifier-specific algorithm. A nested cross-validation was performed for feature selection and model optimization. Base classifiers were the artificial neural network (ANN) and support vector machine (SVM). Base classifiers were also combined with three additional algorithms to improve generalizability performance. Classifications were done with the following groups: (i), non-clear cell RCC (non-cc-RCC) versus clear cell RCC (cc-RCC) and (ii), cc-RCC versus papillary cell RCC (pc-RCC) versus chromophobe cell RCC (chc-RCC). Main performance metric for comparisons was the Matthews correlation coefficient (MCC). RESULTS Number of the reproducible features is smaller for the unenhanced images (93 out of 275) compared to the corticomedullary phase images (232 out of 275). Overall performance metrics of the machine learning-based qCT-TA derived from corticomedullary phase images were better than those of unenhanced images. Using corticomedullary phase images, ANN with adaptive boosting algorithm performed best for discrimination of non-cc-RCCs from cc-RCCs (MCC = 0.728) with an external validation accuracy, sensitivity, and specificity of 84.6%, 69.2%, and 100%, respectively. On the other hand, the performance of the machine learning-based qCT-TA is rather poor for distinguishing three major subtypes. The SVM with bagging algorithm performed best for discrimination of pc-RCC from other RCC subtypes (MCC = 0.804) with an external validation accuracy, sensitivity, and specificity of 69.2%, 71.4%, and 100%, respectively. CONCLUSIONS Machine learning-based qCT-TA can distinguish non-cc-RCCs from cc-RCCs with a satisfying performance. On the other hand, the performance of the method for distinguishing three major subtypes is rather poor. Corticomedullary phase CT images provide much more valuable texture parameters than unenhanced images.

Small bowel intussusception in a pregnant woman with Peutz-Jeghers Syndrome.

Intussusception is the most frequent complication of Peutz–Jeghers Syndrome (PJS), but usually seen in child age. It is a predictable, but infrequent complication in adults with PJS. However, there is no report about intussusception in pregnancy period secondary to Peutz–Jeghers (PJ) polyps in the literature. In this paper, we present a rare intussusception case in a pregnant woman with PJS, which was diagnosed with magnetic resonance imaging, and discuss this condition with a brief literature review.