Effective and organ doses in patient undergoing interventional neuroradiology procedures: A multicentre study.

PURPOSE: Radiation doses to adult patients submitted to cerebral angiography and intracranial aneurysms treatments were assessed by using DICOM Radiation Dose Structured Reports (RDSR) and Monte Carlo simulations. Conversion factors to estimate effective and organ doses from Kerma-Area Product (PKA) values were determined. METHODS: 77 cerebral procedures performed with five angiographic equipment installed in three Italian centres were analyzed. Local settings and acquisition protocols were considered. The geometrical, technical and dosimetric data of 16,244 irradiation events (13305 fluoroscopy, 2811 digital subtraction angiography, 128 cone-beam CT) were extracted from RDSRs by local dose monitoring systems and were input in MonteCarlo PCXMC software to calculate effective and organ doses. Finally, conversion factors to determine effective and organ doses from PKA were determined. Differences between centres were assessed through statistical analysis and accuracy of dose calculation method based on conversion factors was assessed through Bland-Altman analysis. RESULTS: Large variations in PKA (14-561 Gycm2) and effective dose (1.2-73.5 mSv) were observed due to different degrees of complexity in the procedures and angiographic system technology. The most exposed organs were brain, salivary glands, oral mucosa, thyroid and skeleton. The study highlights the importance of recent technology in reducing patient exposure (about fourfold, even more in DSA). No statistically significant difference was observed in conversion factors between centres, except for some organs. A conversion factor of 0.09 ± 0.02 mSv/Gycm2 was obtained for effective dose. CONCLUSIONS: Organ and effective doses were assessed for neuro-interventional procedures. Conversion factors for calculating effective and organ doses from PKA were provided.

Targeted Radiation Therapy Can Treat Myxomatous Cerebral Aneurysms.

BACKGROUND: Neoplastic cerebral aneurysms are rare presentations of cardiac myxomas. The natural history of such aneurysms is not well understood, and the optimal treatment strategy remains unclear. Clipping and coiling are effective, although can carry significant morbidity. Chemotherapy and radiation can theoretically be effective, although their clinical efficacy remains to be proven. CASE DESCRIPTION: Here we describe a patient with cardiac myxoma presenting with multiple progressively fusiform aneurysms. These aneurysms were noted to be growing during conservative monitoring given the eloquent location. Subsequently, the patient underwent multiple sessions of targeted radiation therapy, which lead to obliteration, shrinkage, or halting in growth of these aneurysms. CONCLUSIONS: Low-dose targeted radiation therapy can be safe and effective in treatment of neoplastic myxomatous aneurysms.

Patient radiation dose in diagnostic and interventional procedures for intracranial aneurysms: experience at a single center.

OBJECTIVE: To assess patient radiation doses during cerebral angiography and embolization of intracranial aneurysms in a large sample size from a single center. MATERIALS AND METHODS: We studied a sample of 439 diagnostic and 149 therapeutic procedures for intracranial aneurysms in 480 patients (331 females, 149 males; median age, 57 years; range, 21-88 years), which were performed in 2012 with a biplane unit. Parameters including fluoroscopic time, dose-area product (DAP), and total angiographic image frames were obtained and analyzed. RESULTS: Mean fluoroscopic time, total mean DAP, and total image frames were 12.6 minutes, 136.6 ± 44.8 Gy-cm(2), and 251 ± 49 frames for diagnostic procedures, 52.9 minutes, 226.0 ± 129.2 Gy-cm(2), and 241 frames for therapeutic procedures, and 52.2 minutes, 334.5 ± 184.6 Gy-cm(2), and 408 frames for when both procedures were performed during the same session. The third quartiles for diagnostic reference levels (DRLs) were 14.0, 61.1, and 66.1 minutes for fluoroscopy time, 154.2, 272.8, and 393.8 Gy-cm(2) for DAP, and 272, 276, and 535 for numbers of image frames in diagnostic, therapeutic, and both procedures in the same session, respectively. The proportions of fluoroscopy in DAP for the procedures were 11.4%, 50.5%, and 36.1%, respectively, for the three groups. The mean DAP for each 3-dimensional rotational angiographic acquisition was 19.2 ± 3.2 Gy-cm(2). On average, rotational angiography was used 1.4 ± 0.6 times/session (range, 1-4; n = 580). CONCLUSION: Radiation dose in our study as measured by DAP, fluoroscopy time and image frames did not differ significantly from other reported DRL studies for cerebral angiography, and DAP was lower with fewer angiographic image frames for embolization. A national registry of radiation-dose data is a necessary next step to refine the dose reference level.

Augmented reality in the surgery of cerebral aneurysms: a technical report.

BACKGROUND: Augmented reality is the overlay of computer-generated images on real-world structures. It has previously been used for image guidance during surgical procedures, but it has never been used in the surgery of cerebral aneurysms. OBJECTIVE: To report our experience of cerebral aneurysm surgery aided by augmented reality. METHODS: Twenty-eight patients with 39 unruptured aneurysms were operated on in a prospective manner with augmented reality. Preoperative 3-dimensional image data sets (angio-magnetic resonance imaging, angio-computed tomography, and 3-dimensional digital subtraction angiography) were used to create virtual segmentations of patients' vessels, aneurysms, aneurysm necks, skulls, and heads. These images were injected intraoperatively into the eyepiece of the operating microscope. An example case of an unruptured posterior communicating artery aneurysm clipping is illustrated in a video. RESULTS: The described operating procedure allowed continuous monitoring of the accuracy of patient registration with neuronavigation data and assisted in the performance of tailored surgical approaches and optimal clipping with minimized exposition. CONCLUSION: Augmented reality may add to the performance of a minimally invasive approach, although further studies need to be performed to evaluate whether certain groups of aneurysms are more likely to benefit from it. Further technological development is required to improve its user friendliness.

[Screening for cerebral aneurysms in the ADPKD population: mandatory or potentially harmful?]. / Lo screening degli aneurismi cerebrali nella popolazione ADPKD: un esame irrinunciabile o una procedura potenzialmente dannosa?

Cerebral aneurysm in autosomal dominant polycystic kidney disease (ADPKD) is an uncommon event (documented in 6-13% of cases) but frequently characterized by severe neurological sequelae and potentially fatal in case of rupture. The arterial vascular wall of the anterior cerebral circulation is most frequently involved. Experimental data showed the expression of polycystins (the proteins modified by the mutation in this disease) in the affected arterial vascular wall and some mutations apparently give rise to greater susceptibility to the complication. The risk factors that cause the predisposition to this condition and the natural history are poorly understood. This lack of information complicates the clinical management of these patients because many pivotal questions still need an answer: Are cerebral aneurysms to be screened for in the ADPKD population? If so, at which intervals? In which cases where an aneurysm has been detected is correction needed? Which type of correction technique is to be preferred, interventional neuroradiology or neurosurgery? The three authors compare their partially discordant positions on this highly controversial topic.

Application of microscope integrated indocyanine green video-angiography during microneurosurgical treatment of intracranial aneurysms: a review.

Indocyanine Green Video Angiography (ICG-VA) is recently introduced to the practice of cerebrovascular neurosurgery. This technique is safe and noninvasive and provides reliable real-time information on the patency of blood vessels of any size, as well as residual filling of aneurysms. In this article, a review of the literature and our experience with ICG-VA during microneurosurgery of intracranial aneurysms is presented.

Determination of dosimetric perturbations caused by aneurysm clip in stereotactic radiosurgery using gel phantoms and EBT-Gafchromic films.

Some radiotherapy patients are treated with titanium surgical aneurysm clips in the radiation field. This is of particular importance for stereotactic radiosurgery brain treatments, where the length of the blade of the clip may be comparable to the size of the radiation field. This study seeks to determine the extent of the dosimetric effects caused by surgical clips in stereotactic radiosurgery, using polyacrylamide gel phantoms and EBT type Gafchromic films. Using gel phantoms scanned with magnetic resonance imaging scanner, dose enhancement of around 20% was noted at distances less than 2 mm away from the clip surface. Gafchromic films showed about 6% variations in the dose up to few millimeters from the clip. These experimental results confirmed results predicted by Monte Carlo simulation techniques for higher density material surgical clips such as lead and platinum. Moreover, these experimental measurements clearly indicate dose reduction due to radiation attenuation behind the clip of about 4%.

Local intra-arterial eptifibatide for intraoperative vessel thrombosis during aneurysm coiling.

We report on our experience with the intra-arterial administration of eptifibatide for thrombolysis during aneurysm-embolization procedures. In 4 cases (3 stent-assisted coiling procedures and 1 with posthemorrhagic vasospasm), we noted the formation of thrombus occluding a vessel. We administered eptifibatide (10-15 mg) through a microcatheter proximal to the thrombus. The thrombus rapidly dissolved, resulting in the recanalization of the occluded vessels with no rethrombosis or hemorrhagic complications.

Feasibility of radioactive embolization of intracranial aneurysms using 32P-implanted coils.

BACKGROUND AND PURPOSE: Beta radiation can prevent recanalization after embolization. Our goal was to assess the feasibility of endovascular treatment of intracranial aneurysms using coils of a predetermined activity of 32P per centimeter. METHODS: We studied the total length of coils deployed into 357 intracranial aneurysms. Aneurysmal volumes were estimated using 3 mathematical models. We simulated that coils were implanted with 0.26 microCi/cm of 32P, calculated resulting volumetric activities, and compared them with "effective" levels derived from experimental data and "safe" levels prescribed for the clinical use of 32P in cystic craniopharyngiomas. RESULTS: Effective activities would have been reached in 92% to 98% of lesions had the coils been radioactive at the time of treatment. CONCLUSIONS: Radioactive coil embolization of aneurysms is feasible in most patients.

Patient and occupational dose in neurointerventional procedures.

Neurointerventional procedures can involve very high doses of radiation to the patient. Our purpose was to quantify the exposure of patients and workers during such procedures, and to use the data for optimisation. We monitored the coiling of 27 aneurysms, and embolisation of four arteriovenous malformations. We measured entrance doses at the skull of the patient using thermoluminescent dosemeters. An observer logged the dose-area product (DAP), fluoroscopy time and characteristics of the digital angiographic and fluoroscopic projections. We also measured entrance doses to the workers at the glabella, neck, arms, hands and legs. The highest patient entrance dose was 2.3 Gy, the average maximum entrance dose 0.9+/-0.5 Gy. The effective dose to the patient was estimated as 14.0+/-8.1 mSv. Other average values were: DAP 228+/-131 Gy cm(2), fluoroscopy time 34.8+/-12.6 min, number of angiographic series 19.3+/-9.4 and number of frames 267+/-143. The highest operator entrance dose was observed on the left leg (235+/-174 microGy). The effective dose to the operator, wearing a 0.35 mm lead equivalent apron, was 6.7+/-4.6 microSv. Thus, even the highest patient entrance dose was in the lower part of the range in which nonstochastic effects might arise. Nevertheless, we are trying to reduce patient exposure by optimising machine settings and clinical protocols, and by informing the operator when the total DAP reaches a defined threshold. The contribution of neurointerventional procedures to occupational dose was very small.

A case in favor of aneurysmographic studies: a perforating artery originating from the dome of a basilar tip aneurysm.

A posterior perforating artery originating from the dome of a basilar tip aneurysm is reported. The exact origin of this perforator was identified by selective aneurysmography only. This observation provides an argument favoring the consideration of aneurysmographic studies before treatment of large aneurysms located in proximity to areas of normal perforating arteries.

Management of tentorial dural arteriovenous malformations: transarterial embolization combined with stereotactic radiation or surgery.

The clinical, anatomical, and radiological features of nine cases of tentorial dural arteriovenous malformations (AVM's) are presented, and 45 reported cases are reviewed. Unlike dural AVM's of the transverse sigmoid and cavernous sinuses that usually have a benign natural history, dural AVM's of the tentorium typically present with hemorrhage or progressive neurological deficit. In this series, patients ranged in age from 52 to 72 years and included five men and four women. These patients presented with subarachnoid hemorrhage, parenchymal hemorrhage, brainstem dysfunction, cerebellar signs, and obstructive hydrocephalus. Malformations were fed principally by the meningohypophyseal trunk, branches of the middle meningeal artery, and the occipital artery. Venous drainage was uniform through the cortical veins (predominantly the mesencephalic, petrosal, and cerebellar veins). Eight of the nine patients had an associated venous aneurysm(s); two had more than one venous aneurysm, and two patients had a vein of Galen aneurysm associated with the tentorial dural AVM. Eight of nine patients improved after treatment, including four patients with complete obliteration of the dural AVM. Based on our experience, we have developed a treatment protocol for tentorial dural AVM's that uses transarterial embolization followed by direct microsurgery or stereotactic radiation. These therapies, applied in a staged manner, have proven safe and relatively effective for the treatment of dural AVM's.

Radiosurgery: a nursing perspective.

The term radiosurgery, originally applied to three-dimensional stereotactic irradiation of small intracranial targets with low-energy x-rays, has more recently been applied to widely differing techniques and radiation sources. These include gamma units using cobalt-60; beams of protons, helium ions and neutrons; and modified cobalt-60 or linear accelerator units. These techniques allow delivery of a high dose of radiation in a single fraction to a small and well-defined intracranial volume, without delivering significant radiation to adjacent normal tissue. The most usual targets for radiosurgery are arteriovenous malformations. It is occasionally used for acoustic neuromas and primary or metastatic brain malignancies as well. Although radiosurgery is not a new procedure, its use is becoming more widespread. Nurses, as critical members of radiosurgery teams, must be informed about all aspects of the procedures and associated nursing care skills.