Erratum to "Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion" [Radiology Case Reports 17 (2022) 1848-1852].

[This corrects the article DOI: 10.1016/j.radcr.2022.03.023.].

Carotid web arising in the common carotid artery and adjacent to a transverse process of the cervical spine: A case report.

BACKGROUND AND IMPORTANCE: A carotid web (CaW) is an intraluminal membrane-like filling defect typically located in the posterior wall of the proximal internal carotid artery and is increasingly recognized as a potential cause of embolic stroke. We herein reported a case of a CaW that has an unusual location at the CCA; furthermore, an elongated transverse process of the cervical spine was adjacent to the CaW at the CCA. CLINICAL PRESENTATION: An 87-year-old woman with a history of minor stroke underwent thorough radiological examinations of her CCA lesion. Radiological examinations, including duplex ultrasonography, digital subtraction angiography (DSA), computed tomography, and magnetic resonance angiography, revealed that the morphological characteristics of the lesion were compatible with those of a typical CaW except for its location at the CCA. Furthermore, three-dimensional DSA revealed that the lesion was adjacent to the transverse process of the sixth cervical spine (C6), suggesting mechanical damage by the spinal transverse process as a possible pathogenesis of this CaW. CONCLUSION: This is the rare case of a CaW located in the CCA, far from the carotid bulb. Arterial dissection due to mechanical damage by the spinal transverse process may be a possible causative mechanism of the CaW in the present case.

Acute internal carotid artery occlusion due to dissection of the paraclinoid segment: Diagnostic usefulness of angiographic findings during stent retriever deployment.

Intracranial artery dissection is an uncommon but possible cause of ischemic stroke, and is usually diagnosed based on imaging findings such as mural hematoma and dissection flap. However, it is challenging to recognize the underlying dissection in cases of acute large vessel occlusion. In this report, we present a case of acute internal carotid artery occlusion, in which the underlying dissection of the paraclinoid segment was found during the thrombectomy procedure. Two thrombectomy procedures failed to recanalize the acute internal carotid artery occlusion without removing any clot. Angiography performed during a Trevo stent retriever deployment in the first pass showed obscure contrast defects in the stent strut with temporary flow restoration. In the next pass, the appearance of the contrast defects changed and a parallel linear contrast appeared on the outside of the vessel wall. These angiographic findings were identified as mural hematoma and dissection flap, indicating dissection of the paraclinoid as the cause of the occlusion. During antiplatelet loading and preparation of a dedicated intracranial stent, the Trevo stent retriever was left deployed again at the occlusion site to maintain the blood flow. After permanent stenting with an Enterprise stent, angiography revealed complete recanalization. The patient recovered fully after the procedure. In the present case, stent retriever deployment revealed the hallmarks of dissection on angiography, such as mural hematoma, dissection flap, and temporal morphological changes, by restoring the blood flow temporarily. Such angiographic findings can provide useful information on the occlusion characteristics and real-time feedback for optimal treatment strategy.

Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion.

Mechanical thrombectomy is highly effective for the recovery of acute ischemic stroke with large vessel occlusion. However, refractory occlusions are still encountered despite the use of currently available devices. In this article, we present a case of refractory terminal internal carotid artery occlusion treated with the "crossing double stent retriever technique." Two thrombectomy procedures with the combined technique using a stent retriever and aspiration catheter failed to recanalize the terminal internal carotid artery occlusion that involved the dominant anterior cerebral artery. We then applied the crossing double stent retriever technique as a rescue technique. Two microcatheters were advanced across the occlusion: one to the anterior cerebral artery and the other to the middle cerebral artery. First, a Trevo NXT 4 mm stent retriever was deployed from the anterior cerebral artery. Next, an additional Trevo NXT 4 mm stent retriever was deployed from the middle cerebral artery, and full immediate restoration of flow was achieved on angiography. Intraprocedural radiological images showed that the 2 microcatheters traversed different pathways, and the 2 stent retrievers completely covered the entire vessel with apparent in-stent clot sign. Both stent retrievers were then pulled back together, and a hard clot was retrieved. Subsequent angiography revealed complete recanalization. The crossing double stent retriever technique seems an effective rescue technique for treating refractory terminal internal carotid artery occlusion, especially with the anatomical feature of branching of the dominant anterior cerebral artery. This technique can facilitate the device-clot-vessel interaction by engaging the clot via 2 different device pathways.

Retinal artery embolization during carotid angioplasty and carotid artery stenting: case report.

A 69-year-old man presented with a rare case of retinal artery embolization, which occurred as a complication of carotid angioplasty and carotid artery stenting performed for recurrent cerebral infarction. Magnetic resonance imaging and angiography showed right internal carotid artery stenosis with ulceration. Carotid angioplasty and carotid artery stenting were performed using the distal protection system with the PercuSurge GuardWire. However, just after dilation, the patient complained of ocular pain and blurred vision on the right, which was subsequently diagnosed as retinal artery embolization. Heparin was given for 15 hours after stenting, and aspirin and ticlopidine medication were continued. The patient received hyperbaric oxygen therapy for 1 week. The patient's blurred vision gradually improved, but visual field defect remained. Debris was probably flushed into the external carotid artery, and passed through an anastomosis into the ophthalmic artery, resulting in retinal artery embolization.

Optimization and evaluation of networked single-wall carbon nanotubes as a NO(2) gas sensing material.

We have prepared conductometric NO(2) gas sensors based on single-wall carbon nanotube (SWNT) networks. The SWNT properties are modified systematically by varying the annealing temperature between 350 to 550 degrees C under vacuum. Thermal annealing is not only necessary to remove dispersant used for nanotube dispersion but also plays an important role in optimizing the gas sensing abilities. In this paper, the sensing performance is evaluated through three crucial sensing characteristics: sensitivity to NO(2), humidity interfering effect, and sensor stability over repeated use, all examined at room temperature. The sensor annealed at 400 degrees C shows the highest NO(2) sensitivity because of the structural properties, i.e., high specific surface area and the molecular geometry of having all carbon atoms at the tube-surface. The sensor also shows negligible humidity interfering effect and high sensor stability, originating from the hydrophobicity and chemical stability of the material, respectively. In contrast, annealing temperatures higher than 400 degrees C lead to structural defects in SWNTs and thus lower the sensing performance. We experimentally confirm that these SWNT characteristics make SWNTs a suitable gas sensing material from a practical perspective.

Enhanced performance of a filter-sensor system.

In this paper are addressed two important, but seemingly unrelated issues: long term performance of a gas sensing array and performance of an air purification unit. It is shown that when considered together, the system can be regarded as a "smart filter". The enhancement is achieved by periodic differential sampling and measurement of the "upstream" and "downstream" gases of a filter. The correctly functioning filter supplies the "zero gas" from the downstream for the continuous sensor baseline correction. A key element in this scheme is the synthetic jet that delivers well-defined pulses of the two gases. The deterioration of the performance of the "smart filter" can be diagnosed from the response pattern of the sensor. The approach has been demonstrated on removal/sensing of ammonia gas from air.

Chronic demyelinating polyneuropathy in graft-versus-host disease following allogeneic bone marrow transplantation.

In recent years a novel problem has arisen in organ transplantation medicine, namely GVHD. The nervous system has been involved mainly at the level of the CNS and this can lead to a serious outcome for the patient. In rare cases, peripheral nerves may be affected and show acute or chronic polyneuropathy. Here a case is reported of polyneuropathy associated with chronic GVHD. A 32-year-old man, suffering from chronic GVHD following an allogeneic bone marrow transplantation (BMT) for malignant lymphoma at the age of 25, developed a motor dominant polyneuropathy 5 years later. Electrophysiologic studies demonstrated the demyelinating type of polyneuropathy. Biopsy specimens from skin and skeletal muscle disclosed perivascular lymphocytic infiltrates expressing T-cell markers. The sural nerve showed a loss of myelinated nerve fibers with epineurial fibrosis and rare occurrence of T cells, but without obvious vasculitic changes. The present case suggested that polyneuropathy could develop in association with chronic GVHD in some patients with a long-standing disease course.