Assessment of Cerebral Circulatory Arrest via CT Angiography and CT Perfusion in Brain Death Confirmation.

OBJECTIVE: To compare the utility of computed tomography perfusion (CTP) and three different 4-point scoring systems in computed tomography angiography (CTA) in confirming brain death (BD) in patients with and without skull defects. MATERIALS AND METHODS: Ninety-two patients clinically diagnosed as BD using CTA and/or CTP for confirmation were retrospectively reviewed. For the final analysis, 86 patients were included in this study. Images were re-evaluated by three radiologists according to the 4-point scoring systems that consider the vessel opacification on 1) the venous phase for both M4 segments of the middle cerebral arteries (MCAs-M4) and internal cerebral veins (ICVs) (A60-V60), 2) the arterial phase for the MCA-M4 and venous phase for the ICVs (A20-V60), 3) the venous phase for the ICVs and superior petrosal veins (ICV-SPV). The CTP images were independently reviewed. The presence of an open skull defect and stasis filling was noted. RESULTS: Sensitivities of the ICV-SPV, A20-V60, A60-V60 scoring systems, and CTP in the diagnosis of BD were 89.5%, 82.6%, 67.4%, and 93.3%, respectively. The sensitivity of A20-V60 scoring was higher than that of A60-V60 in BD patients (p < 0.001). CTP was found to be the most sensitive method (86.5%) in patients with open skull defect (p = 0.019). Interobserver agreement was excellent in the diagnosis of BD, in assessing A20-V60, A60-V60, ICV-SPV, CTP, and good in stasis filling (κ: 0.84, 0.83, 0.83, 0.83, and 0.67, respectively). CONCLUSION: The sensitivity of CTA confirming brain death differs between various proposed 4-point scoring systems. Although the ICV-SPV is the most sensitive, evaluation of the SPV is challenging. Adding CTP to the routine BD CTA protocol, especially in cases with open skull defect, could increase sensitivity as a useful adjunct.

Mastoid Emissary Vein Canal Incidence and Its Relationship with Jugular Bulb and Sigmoid Sulcus Anatomical Variations.

Objective: We aimed to investigate the mastoid emissary vein (MEV) canal incidence and to identify its relationship with jugular bulb (JB) and sigmoid sulcus anatomical variations. Methods: We retrospectively reviewed 1,300 patients with temporal bone computed tomography (CT) scans in January 2016 to March 2020. The presence and the diameter of the MEV canal, and the anatomical variations of the sigmoid sulcus and the JB were reviewed by two radiologists. High riding JB, JB diverticulum, dehiscent JB, and anterior and lateral protrusion of the sigmoid sulcus were evaluated. All variables were summarized using descriptive statistics. The differences between the groups for categorical data were investigated using the chi-square test. Numeric variables were compared with the Mann-Whitney and the Kruskal-Wallis tests. Logistic regression models were constructed. Results: The study included 1,269 patients of whom 694 were female (54.7%) and 575 were male (45.3%). Their mean age was 39.01±18.47. Among them 915 (72.1%) had the right and 871 (68.6%) had the left MEV canal. Men were more likely to have the MEV canal on both sides. The presence of the right and left MEV canals was associated with the ipsilateral dominant JB/sigmoid sulcus. The left MEV canal was associated with the left high riding JB and right dehiscent JB. Conclusion: This is the largest patient population reported in the literature and allows a more precise estimate of the MEV canal incidence. We also classified the diameter of the MEV canal to identify clinically relevant, prominent MEV incidence. This is also the first study to demonstrate a relationship between the presence of the MEV canal, and the JB and sigmoid canal variations. Since both the prominent MEV and the JB variations may be symptomatic, knowing this association between them may have clinical relevance.

Percutaneous Intraductal Microwave Ablation and Self-expandable Metallic Stenting: A New Treatment Method for Malignant Extrahepatic Biliary Obstruction.

PURPOSE: To evaluate the patency and clinical efficacy of percutaneous intraductal microwave ablation (PIMWA) and uncovered self-expandable metallic stents (USEMs) in inoperable malignant extrahepatic biliary obstruction. MATERIALS AND METHODS: The procedures to be performed on patients with malignant inoperable extrahepatic biliary obstruction were decided by a multidisciplinary team including an interventional radiologist. In our study, 141 patients were evaluated retrospectively. Twenty-one patients who underwent PIMWA + USEMs with the MedWaves AveCure microwave system (AveCure® Intelligent Controller and Super-Flex Smart Catheter) and met the inclusion criteria were included in the study. Complications related to the intervention, stent patency, survival time, serum bilirubin levels, and the general condition of the patients were noted. RESULTS: The median stent patency and the median survival time were 108 and 143 days, respectively. The rates of 30-day, 2-month, 6-month and 8-month survival were 95.2%, 85.7%, 38.1%, and 14.3%, respectively. CONCLUSION: The PIMWA + USEMs procedure is a safe, effective, and minimally invasive alternative palliative treatment method in patients with malignant inoperable extrahepatic biliary obstruction.

Percutaneous Treatment of Giant Cystic Echinococcosis in Liver: Catheterization Technique in Patients with CE1 and CE3a.

PURPOSE: This study aimed to evaluate the efficacy, safety, and follow-up results of the percutaneous treatment of cystic echinococcosis (CE) patients with giant hepatic cysts (at least one diameter > 10 cm). METHODS: Between January 2013 and 2018, 31 CE patients with 34 giant cysts classified as CE1 or CE3a (Gharbi type 1 or 2) according to the World Health Organization criteria and treated with the catheterization technique were analyzed retrospectively. RESULTS: Thirty-four giant hepatic cysts were treated using the catheterization technique. Technical success was 100%. One procedure was sufficient for 27 of these cysts, while six patients underwent a second procedure due to recurrence, recollection or complications; one did not accept a repeat procedure and decided to refer to surgery due to pain. Ten (29%) major complications developed. The overall clinical success was 97%. The mean follow-up period was 20 months (5-61 months), and the total reduction in the cyst volume was 92%. CONCLUSION: The catheterization technique is effective in treating giant CE with acceptable complication rates. LEVEL OF EVIDENCE: Level 4, Clinical Investigation.

Implementation of the EXOSEAL Vascular Closure Device in the Transpopliteal Arterial Approach.

PURPOSE: To investigate the feasibility and safety of the EXOSEAL vascular closure device (VCD) in achieving hemostasis in transpopliteal arterial interventions. MATERIALS AND METHODS: Between May 2014 and May 2016, 46 procedures involving transpopliteal arterial access in 28 patients (18 bilateral and 10 unilateral) were analyzed retrospectively. Popliteal arterial puncture was performed under ultrasonographic (US) and fluoroscopic guidance by using a micropuncture access set with a 21-gauge needle. Six-French sheaths were used in 45 procedures, and a 7-F sheath was used in 1 procedure. Hemostasis was achieved with the EXOSEAL VCD. All patients were examined for any access-related complications with US at 6 and 24 hours after the procedure. One week later, all patients were followed up in the outpatient clinic. RESULTS: In 44 of the 46 procedures, the EXOSEAL VCD was applied successfully. The technical failure rate was 4.4%. An excessively steep angle of the introducer sheath and improper placement of the EXOSEAL plug in the setting of high blood pressure (220/120 mm Hg) were the reasons for the 2 failures. Among the 44 successful procedures, 1 (2.3%) minor 3-cm hematoma was found to be associated with the VCD. In 1 of the 46 procedures, an arteriovenous fistula (2.2%) was observed as a puncture-related complication and treated with a stent graft. CONCLUSIONS: The EXOSEAL VCD can be safely used for hemostasis in interventions that use transpopliteal arterial approaches, with a high technical success rate and a low rate of entry-site complications.

Prevalence of clinically important posterior fossa emissary veins on CT angiography.

PURPOSE: We assessed the prevalence of the clinically important posterior fossa emissary veins detected on computed tomography (CT) angiography. MATERIALS AND METHODS: A total of 182 consecutive patients who underwent 64-slice CT angiography were retrospectively reviewed to determine the clinically important posterior fossa emissary veins. RESULTS: Of 166 patients, the mastoid emissary vein (MEV) was not identified in 37 (22.3%) patients. It was found bilaterally in 82 (49.4%) and unilaterally in 47 (28.3%) patients. Only six patients had more than one MEV that were very small (<2 mm), and only five patients had very large (>5 mm) veins. The posterior condylar vein (PCV) was not identified in 39 (23.5%) patients. It was found bilaterally in 97 (58.4%) and unilaterally in 30 (18.1%) patients. Only 15 patients had a very large (>5 mm) PCV. The petrosquamosal sinus (PSS) was identified only in one patient (0.6%) on the left side. The occipital sinus was found in two patients (1.2%). CONCLUSIONS: The presence of the clinically important posterior fossa emissary veins is not rare. Posterior fossa emissary veins should be identified and systematically reported, especially prior to surgeries involving the posterior fossa and mastoid region.

Variations of the cerebellar arteries at CT angiography.

PURPOSE: There are few studies that investigated variations of the cerebellar arteries, and the prevalence of some variations has not been reported. We aim to identify and evaluate variations of the cerebellar arteries using CTA. METHODS: The findings in 341 patients who underwent 64-slice CTA were reviewed for anatomical variations of the cerebellar arteries. We assessed variations and classified our findings to describe the results of our analysis. We attempted to create an anatomical model for CTA that is somewhat different from previous studies and described our findings according to vascular anatomy. RESULTS: Only 11.7% of the 341 patients had all the cerebellar arteries without anatomical variations. Vertebral artery continuation as posterior inferior cerebellar artery (PICA) was found in 4.4% of the patients. Absence of the anterior inferior cerebellar artery (AICA) was observed in 36.1%, and absence of the PICA was observed in 6.7% of the patients. The origin of the PICA was extradural in 71 (20.8%) patients. Double origin of the PICA, PICA duplication, and fenestration were rarely found. Duplication of the AICA (7.9%), and superior cerebellar artery (SCA) (20.5%), and early bifurcation of SCA (9.4%) were frequently observed. Superior cerebellar artery and posterior cerebral artery (PCA) common trunk and SCA originating from PCA were found 9.4 and 8.2%, respectively. CONCLUSION: Variations of the cerebral arteries can be easily evaluated by CTA. Recognizing and reporting them at cerebral CT angiography may be clinically important.

Why should we report posterior fossa emissary veins?

Posterior fossa emissary veins are valveless veins that pass through cranial apertures. They participate in extracranial venous drainage of the posterior fossa dural sinuses. The mastoid emissary vein, condylar veins, occipital emissary vein, and petrosquamosal sinus are the major posterior fossa emissary veins. We believe that posterior fossa emissary veins can be detected by radiologists before surgery with a thorough understanding of their anatomy. Describing them using temporal bone computed tomography (CT), CT angiography, and cerebral magnetic resonance (MR) venography examinations results in more detailed and accurate preoperative radiological interpretation and has clinical importance. This pictorial essay reviews the anatomy of the major and clinically relevant posterior fossa emissary veins using high-resolution CT, CT angiography, and MR venography images and discusses the clinical importance of reporting these vascular variants.

Three-dimensional CT imaging in pediatric calvarial pathologies.

In children with suspected cranial pathologies, three-dimensional (3D) computed tomography (CT) imaging is superior to other modalities. It can help differentiate actual pathology from normal or variant appearances. Sutures and fontanelles, synostosis, abnormalities of head shape without craniosynostosis, congenital calvarial defects, cranial fractures, bone tumors, and postoperative cranial vault can be assessed easily with 3D CT imaging. We aimed to discuss the common normal, variant, and pathological findings that 3D CT imaging can aid to diagnose as well as explain the usefulness of 3D CT imaging in the diagnosis of calvarial pathologies.