Objective: We investigated the fluoroscopy time (FT) and radiation dose by the number of cerebral angiography (CA) operator experiences to clarify the learning curve of CA.

Methods: The subjects were cases for whom CA was performed at our hospital for 5 years between April 2015 and March 2020. Based on the number of CA operator experiences, they were classified into four groups: 1–50 cases (group A), 51–100 cases (group B), 101–200 cases (group C), and 201 cases and later (group D). The FT and radiation dose were retrospectively investigated.

Results: Of the 865 consecutive CA cases, 293 cases for follow-up, i.e. after treatment, 54 for arteriovenous shunt diseases, 21 lacking data, and 1 case requiring intervention for thrombosis during CA were excluded. In total, 496 CA cases were investigated. There were 61 cases in group A, 56 cases in group B, 44 cases in group C, and 335 cases in group D, and there was no significant difference in patient background factors among the groups. The median FT and radiation dose (interquartile range) in each group were 20.2 min (14.6) and 374 mGy (185.3) in group A, 14.8 min (12.1) and 366 mGy (167.9) in group B, 10.8 min (6) and 320 mGy (151.7) in group C, and 9.4 min (6.4) and 336 mGy (171) in group D. The FT was significantly shorter in group C than in group A, and significantly shorter in group D than in groups A, B, and C. The radiation dose was significantly lower in groups C and D than in groups A and B.

Conclusion: This study suggested that CA can be performed alone after experiencing approximately 100 cases as an operator.

Objective: As an important evaluation index of vascular damage, the study aims to clarify the value of contact pressure applied to blood vessels and how it changes with respect to balloon pressure during balloon dilation.

Methods: The contact pressure was evaluated through an in vitro measurement system using a model tube with almost the same elastic modulus as the blood vessel wall and our film-type pressure sensor. A poly (vinyl alcohol) hydrogel tube with almost the same elastic modulus was fabricated as the model vessel. The film-type sensor was inserted between the balloon catheter and the model vessel, and the balloon was dilated.

Results: The contact pressure applied to the blood vessel was less than 10% of the balloon pressure, and the increase in contact pressure was less than 1% of the increase in balloon pressure (8 to 14 atm). Moreover, the contact pressure and its increase were larger in the model with a high elastic modulus.

Conclusion: The contact pressure to expand the soft vessel model was not high, and the balloon pressure almost appeared to act on the expansion of the balloon itself. Our experiment using variable stiffness vessel models containing film-type sensors showed that the contact pressure acting on the vessel wall tended to increase as the wall became harder, even when the nominal diameter of the balloon was almost identical to the vessel. Our results can be clinically interpreted: when a vessel is stiff, the high-pressure inflation may rupture it even if its nominal diameter is identical to the diameter of the vessel.

Objective: Cervical dislocated fractures frequently cause vertebral artery injury (VAI), which, in turn, propagates the thrombus at the site of injury. Cerebral embolism due to a thrombus after the reduction of dislocation leads to a poorer neurological outcome. Therefore, we investigated the outcome of treatment for cervical dislocated fractures and the usefulness of parent artery occlusion (PAO) before reduction.

Methods: Eight patients with cervical dislocated fractures with a locked facets treated at our hospital between January 2018 and December 2020 were evaluated. We retrospectively examined patient characteristics and clinical outcomes.

Results: Among the eight patients, two were injured at C4/5, four at C5/6, and two at C6/7. All patients had locked facets. Four patients had bilateral dislocation, while the others had unilateral dislocation. Two patients with unilateral dislocation had ipsilateral vertebral artery occlusion (VAO), while the other six did not. Both patients with VAO underwent PAO to prevent cerebral embolism before reduction. The six patients who did not have VAI underwent reduction without preprocedural treatment. No cerebral ischemic complications were observed. One patient died due to paralysis of the respiratory muscles caused by spinal cord injury but the remaining seven recovered well.

Conclusion: PAO before reduction for cervical dislocated fractures with VAO may be effective in preventing cerebral embolism after reduction.

Objective: Large vessel occlusion (LVO) stroke during pregnancy is rare but a life-threatening issue for the mother and fetus. We report a rare case of a pregnant woman with congenital protein S deficiency who underwent mechanical thrombectomy.

Case Presentation: A 35-year-old woman presented with right hemiplegia and aphasia. The National Institutes of Health Stroke Scale was 23 and MRI revealed acute infarction on the left hemisphere. MRA showed disruption of the left middle cerebral artery. Mechanical thrombectomy was performed following intravenous thrombolysis, and then complete recanalization was achieved. The reduction in protein S activity due to pregnancy was suspected to have affected LVO. Subsequently, the patient was diagnosed with congenital protein S deficiency and recovered to modified Rankin scale 2 at 3 months after the onset.

Conclusion: Aggravation of congenital protein S deficiency due to pregnancy led to the onset of LVO. The patient showed a good outcome after mechanical thrombectomy.

Objective: We report the case of a patient with recurred idiopathic intracranial hypertension (IIH) with transverse sinus (TS) stenosis after initial stenting, which was treated with additional stent placed in tandem to the secondarily occurred stent-adjacent stenosis (SAS).

Case Presentation: A 41-year-old woman complained of reduced visual acuity and blurred vision, and presented with papilledema. Lumbar puncture revealed an opening pressure of 36 cmH₂O. MRI revealed no space-occupying lesions, and the patient was diagnosed with IIH based on the modified Dandy criteria. MR venography revealed stenosis in the right and hypoplastic left TS. The patient complained of headache and neck pain after each lumbar puncture for examination. Venous sinus stenting (VSS) was performed in the right TS. One month after stenting, follow-up angiography revealed stenosis in the remaining parts of TS. Five months after stenting, IIH recurred, and SAS was detected on angiography. An additional stenting procedure was performed. Three months after the second treatment, her symptoms disappeared and cerebrospinal fluid pressure was normalized.

Conclusion: Patients with post-VSS recurrent IIH may develop restenosis in the remaining parts of TS at variable progression speeds. In this case, angiography revealed gradually advancing stenosis that seemed to form SAS at the time of recurrence. If the initial VSS is effective for IIH, SAS can also be treated effectively and less invasively with a second stent placement covering the entire TS length.

Objective: We present a case of intraprocedural device malfunction related to the JET 7 Xtra Flex reperfusion catheter during mechanical thrombectomy.

Case Presentation: A 92-year-old man presented with sudden right hemiparesis with a National Institutes of Health Stroke Scale score of 22. His left middle cerebral artery (M1) was occluded, and emergency mechanical thrombectomy was performed. After partial recanalization was achieved, angiography through a JET 7 Xtra Flex was attempted. After manual injection of contrast media via a 10-mL syringe through the JET 7 Xtra Flex, the catheter moved, jumping forward, and the distal tip of the catheter expanded and ruptured. This resulted in intracranial vessel damage and subsequent patient death.

Conclusion: Contrast media must not be injected through the JET 7 Xtra Flex. If contrast media needs to be injected for angiography during mechanical thrombectomy with a reperfusion catheter, it should always be through the guide catheter.

Objective: Laterocavernous sinus dural arteriovenous fistulas (DAVFs) are rare and not always accessible transvenously due to their angioarchitecture. We report a case of non-sinus-type laterocavernous sinus DAVF treated by endovascular transarterial venous coil embolization.

Case Presentation: A 78-year-old woman was admitted to our hospital with loss of consciousness, right hemiparesis, and motor aphasia. CT demonstrated intracerebral hematoma in the left frontal lobe and subarachnoid hemorrhage. On CTA and MRA, a DAVF was found in the left laterocavernous sinus region associated with the accessory meningeal artery (AMA) and draining directly into the superficial middle cerebral vein. The diagnosis was confirmed by DSA, which revealed a DAVF fed by the large and straight AMA and the internal carotid artery’s meningohypophyseal trunk. Endovascular transarterial venous coil embolization was performed through the AMA. A microcatheter was advanced beyond the shunt point into the origin of the draining vein, and coils were placed in the venous and arterial sides of the fistula. The fistula was completely occluded, and 15-month follow-up angiography demonstrated stable obliteration of the fistula.

Conclusion: Transarterial venous coil embolization may be a treatment option for non-sinus-type laterocavernous sinus DAVF with a large fistula size and a large and straight feeding artery.

Objective: Standard thrombectomy techniques, including stent retrieval and a direct aspiration first pass technique, are not effective when the occluded vessel is narrow and sharply bifurcated from the main trunk. Here, we present a new and alternative method for patients with such anatomical features and describe two cases treated by this method.

Case Presentations: Case 1 was a 66-year-old woman who presented with consciousness disturbance and left hemiparesis. MRA suggested a right middle cerebral artery occlusion. Case 2 was an 86-year-old man who presented with sudden onset of consciousness disturbance; MRA indicated occlusion of the basilar artery. Both cases were successfully treated by our new method. First, we navigated a microcatheter, microguidewire, and aspiration catheter into the patent and visible branch adjacent to the occluded branch. The aspiration catheter was then carefully pulled back with continuous mechanical aspiration. When reverse blood flow from the aspiration catheter was suspended, we slightly advanced the catheter and caught the thrombus. Complete recanalization was attained in the two cases treated with this technique, which was named as sideway aspiration technique (SAT).

Conclusion: Although it warrants further study, SAT may be a potentially safe and effective method for thrombectomy in cases with thrombus in a sharply bifurcated branch.