Intracranial magnetic resonance angiography

Transvenous embolization along with intraprocedural image fusion technique for complex intracranial dural arteriovenous fistula

PURPOSE

This study aimed to investigate the efficacy and safety of an intraprocedural image fusion technique using flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) for the transvenous approach in treating intracranial dural arteriovenous fistulas (dAVFs).

METHODS

A retrospective review was conducted on patients who underwent transvenous embolization for dural AVFs. The patients were classified into two groups according to the treatment technique used: the FDCT-RA and IF technique group and the conventional technique group. The primary outcomes assessed were the angiographic and clinical outcomes, complications, fluoroscopy time, and radiation exposure. Univariate analyses were performed to compare the two treatment modalities.

RESULTS

Eighty-six patients with intracranial dAVFs were treated with transvenous embolization (TVE), of which 37 patients underwent transvenous approach with flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) technique used. The FDCT-RA and IF group showed difference in the location of dAVFs, occlusion state of the sinus, and access routes in comparison to the conventional treatment group. The FDCT-RA and IF technique was predominantly used for dAVFs involving the anterior condylar confluence and cavernous sinus with ipsilateral inferior petrosal sinus (IPS) occlusion. Patients treated with this technique demonstrated a higher rate of complete occlusion (91.9%, n = 34) compared to those treated with the conventional technique (79.6%, n = 39), but this difference was not statistically significant (p = 0.136). Although the implementation of this technique during the treatment procedure showed a tendency to decrease both fluoroscopy duration and radiation dose, the observed results did not reach statistical significance (p = 0.315, p = 0.130).

CONCLUSION

The intraprocedural image fusion technique using FDCT-RA for transvenous treatment of intracranial dAVFs could provide help in treatment of dAVFs of certain locations or access routes. It might provide aid in microcatheter navigation, without increasing the radiation exposure and fluoroscopy time.

Age-dependent Intracranial Artery Morphology in Healthy Children

PURPOSE

Evaluation of intracranial artery morphology plays an important role in diagnosing a variety of neurovascular diseases. In addition to clinical symptoms, diagnosis currently relies on qualitative rather than quantitative evaluation of vascular imaging sequences, such as magnetic resonance angiography (MRA). However, there is a paucity of literature on normal arterial morphology in the pediatric population across brain development. We aimed to quantitatively assess normal, age-related changes in artery morphology in children.

METHODS

We performed retrospective analysis of pediatric MRA data obtained from a tertiary referral center. An MRA dataset from 98 children (49 boys/49 girls) aged 0.6-20 years (median = 11.5 years) with normal intracranial vasculature was retrospectively collected between 2011 and 2018. All arteries were automatically segmented to determine the vessel radius. Using an atlas-based approach, the average radius and density of arteries were measured in the three main cerebral vascular territories and the radius of five major arteries was determined at corresponding locations.

RESULTS

The radii of the major arteries as well as the average artery radius and density in the different vascular territories in the brain remained constant throughout childhood and adolescence (|r| < 0.369 in all cases).

CONCLUSION

This study presents the first automated evaluation of intracranial vessel morphology on MRA across childhood. Our results can serve as a framework for quantitative evaluation of cerebral vessel morphology in the setting of pediatric neurovascular diseases.

Inner Ear Conductive Hearing Loss and Unilateral Pulsatile Tinnitus Associated with a Dural Arteriovenous Fistula: Case Based Review and Analysis of Relationship between Intracranial Vascular Abnormalities and Inner Ear Fluids

While pulsatile tinnitus (PT) and dural arteriovenous fistula (DAVF) are not rarely associated, the finding of a conductive hearing loss (CHL) in this clinical picture is unusual. Starting from a case of CHL and PT, diagnosed to be due to a DAVF, we analyzed relationship between intracranial vascular abnormalities and inner ear fluids. DAVF was treated with endovascular embolization. Following this, there was a dramatic recovery of PT and of CHL, confirming their cause-effect link with DAVF. We critically evaluated the papers reporting this association. This is the first case of CHL associated with PT and DAVF. We describe the most significant experiences and theories reported in literature, with a personal analysis about the possible relationship between vascular intracranial system and labyrinthine fluids. In conclusion, we believe that this association may be a challenge for otolaryngologists. So we suggest to consider the possibility of a DAVF or other AVMs when PT is associated with CHL, without alterations of tympanic membrane and middle ear tests.

Improvement of the diagnostic accuracy of MRA with subtraction technique in cerebral vasospasm

PURPOSE

Vasospasm has been considered the most severe acute complication after subarachnoid hemorrhage (SAH). MRA is not considered ideal for detecting cerebral vasospasm because of background including the hemorrhage. The aim of this study is to evaluate the efficacy of Subtraction MRA (SMRA) by comparing it to that of conventional MRA (CMRA) for diagnosis of cerebral vasospasm.

METHODS

Arteries were assigned to one of three categories based on the degree of MRA diagnostic quality of vasospasm (quality score): 0, bad … 2, good. Furthermore each artery was assigned to one of four categories based on the degree of vasospasm severity (SV score): 0, no vasospasm … 3, severe. The value of the difference between DSA-SV score and MRA-SV score was defined as the DIF score. CMRA and SMRA were compared for each arterial region with regard to quality score and DIF score.

RESULTS

The average CMRA and SMRA quality score were 1.46 and 1.79; the difference was statistically significant. The average CMRA and SMRA DIF score were 1.08 and .60; the difference was statistically significant.

CONCLUSIONS

Diagnosis of cerebral vasospasm is more accurate by SMRA than by CMRA. The advantages are its noninvasive nature and its ability to detect cerebral vasospasm.

Advanced imaging modalities in the detection of cerebral vasospasm

The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, ¹³³Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.

The use of CT-angiography for monitoring thrombus formation after balloon occlusion of a dissecting vertebral artery pseudoaneurysm

We present a 49-year-old man with a subarachnoid haemorrhage from a dissecting vertebral artery (VA) pseudoaneurysm treated with a proximal balloon occlusion. The clinical course was complicated by the sudden appearance of a lateral medullary syndrome (Wallenberg), which completely resolved after anticoagulant therapy. During this course, CT-angiography (CTA) enabled monitoring of both the progression and partial resolution of the thrombus in the occluded VA. An anatomical variant of a perforating artery originating from the VA proximal to the posterior inferior cerebral artery (PICA) was subsequently demonstrated, explaining the ischemic event. The value of CTA in clinical management is discussed. The prophylactic use of anticoagulant therapy especially in the case of a perforating artery to the lateral medulla originating proximally to the PICA, is suggested.

Penetrating head injury in children: a case report and review of the literature

Head trauma is exceedingly common in children, but rarely presents as a penetrating injury to the skull. Most of the recommendations on evaluation, management, and follow-up of such injuries are based on the adult literature. We report a case of penetrating head injury from a tapered metal object in a 4-year old child.

Magnetic resonance angiography of the intracranial vessels

In this overview the results and indications of Magnetic Resonance Angiography of the intracranial vasculature will be discussed. The value of MRA will be studied in the visualisation of normal variants of the cerebral anatomy, the imaging of cerebrovascular disease, the diagnosis of aneurysms and cerebral arteriovenous malformations, the preoperative setup of cerebral tumors and the demonstration of vascular compression.

Risk of harboring an unruptured intracranial aneurysm

BACKGROUND AND PURPOSE

The purpose of the present study was to calculate the prevalence and relative risk of unruptured incidental intracranial aneurysms (IAs) among families with IA case(s) compared with the general population in one geographically defined area in East Finland and to identify the risk group that could benefit most from screening for IAs. We compared these results with our earlier study results of familial IA (FIA) cases, with two or more known IA cases in the same family.

METHODS

The study groups were collected from the catchment area of the University Hospital of Kuopio in East Finland. The inclusion criteria were age 30 to 70 years and unruptured incidental IAs > or =3 mm. Patients with previous subarachnoid hemorrhage or in whom a ruptured IA was found to be the cause of death were excluded from all study groups. During routine forensic autopsies the circle of Willis was studied for IAs to estimate the number of IAs in the general population. In the families with one known IA case and in FIA families, MR angiography was used as a preliminary screening method for IAs, followed by intra-arterial angiography to verify suspected IAs. Study populations were age and sex adjusted for the statistical calculations.

RESULTS

The relative risk for IAs among first-degree relatives in FIA families was 4.2 (95% confidence interval, 2.2 to 8.0) and among first-degree relatives in families with only one affected family member was 1.8 (95% confidence interval, 0.7 to 4.8) compared with the general population in East Finland.

CONCLUSIONS

First-degree relatives in FIA families constitute a high-risk group for incidental IAs, and this group would benefit from screening studies for IAs. Screening for IAs in families with only one affected member or in the general population is not recommended.

Use of Magnetic Resonance Imaging and Magnetic Resonance Angiography in Diagnosis of Sigmoid Sinus Thrombosis

Magnetic resonance angiography is an established radiologic technique which is rapidly becoming useful in imaging the head and neck. Currently, this imaging modality is important in the diagnosis of sigmoid sinus thrombosis caused by otologic disease. Since the introduction of antibiotic therapy, the percentage of deaths attributed to intracranial complications from otitic disease has decreased from 2.5 to approximately 0.25% of documented deaths. Also, the incidence of sinus thrombosis within this group has decreased, but it is still a serious and potentially lethal condition.

Sinus thrombosis is suspected clinically when mastoid disease progresses, with picket fence fever pattern, chills, headaches and signs of papilledema. Definitive diagnosis is necessary before surgical treatment. The Queckenstedt test is unreliable, computed tomography is better suited for demonstrating thrombosis of the sagittal sinus rather than the sigmoid sinus, and conventional angiography (although it provides excellent visualization) has the hazard of ionizing radiation and requires vessel puncture and the use of intraarterial contrast agents.

We present two cases of thrombosis of the sigmoid sinus as an intracranial otologic complication which were diagnosed definitively with magnetic resonance imaging and magnetic resonance angiography. The combination of magnetic resonance imaging, which showed the thrombosis displaying abnormal signal intensity, and magnetic resonance angiography, which demonstrated the absence of flow in the sinus, was an ideal diagnostic tool. For both patients, treatment consisted of mastoidectomy, sigmoid sinus decompression and antibiotics.

Spontaneous pulsatile tinnitus secondary to a dural malformation not visualized by magnetic resonance angiography

The author describes a case of tinnitus secondary to a right dural malformation not visualized by magnetic resonance angiography. The prime role of computed tomography/angiography is emphasized.

The evaluation of headaches in children and adolescents

The importance of a thorough evaluation of each patient with headache is stressed. Details of the data base, pertinent information regarding the physical examination, and thoughts concerning selection of laboratory tests are provided. The majority of headache types seen in pediatric practice can correctly be identified using these methodologies.

Transcranial Doppler sonography and magnetic resonance angiography in the assessment of collateral hemispheric flow in patients with carotid artery disease

BACKGROUND AND PURPOSE

The aim of this investigation was to compare the respective efficacy of transcranial Doppler sonography (TCD) and magnetic resonance angiography (MRA) for the assessment of intracranial hemodynamics in patients with extracranial occlusion or severe stenosis of the internal carotid artery (ICA).

METHODS

Twenty-five patients with unilateral ICA occlusion (n = 20) or tight stenosis (n = 5) demonstrated by duplex scanning or angiography were studied with both TCD and MRA. Three-dimensional time-of-flight MRA was used for the evaluation of extracranial-intracranial ICAs. Collateralization through the circle of Willis was investigated by means of selective two-dimensional MRA with presaturation of the carotid siphon, ophthalmic artery, or basilar artery. TCD was performed according to published standards: Anterior, middle, and posterior cerebral arteries were insonated through the temporal window, and carotid siphon and ophthalmic artery were assessed through a transorbital approach. Collateralization through the anterior circle of Willis was assumed if anterior cerebral artery flow was reversed, through the external carotid artery if ophthalmic artery flow was reversed, and through the basilar artery if the ratio of ipsilateral to contralateral posterior cerebral artery velocity was greater than 50%. TCD and MRA were performed by different investigators unaware of the results obtained with the other technique.

RESULTS

In every case time-of-flight MRA demonstrated the ICA occlusion or stenosis. There was an excellent correlation (kappa = 0.64) between TCD and MRA in assessing the hemodynamic contribution of the anterior part of the circle of Willis, whereas MRA was unable to detect the anastomotic pathway of the ophthalmic artery (kappa = 0.32). The contribution of the posterior communicating artery was difficult to assess with both techniques, but in three cases only MRA showed unequivocal evidence of collateralization. In three cases of middle cerebral artery stenosis TCD was superior to MRA in demonstrating the patency of the vessel.

CONCLUSIONS

TCD and MRA should be considered complementary techniques. Combining the findings of both examinations may help to better understand the changes in intracranial hemodynamics produced by extracranial carotid occlusion. The contribution of the ophthalmic pathway, although important for the intraorbital structures, is probably of limited functional significance to the hemispheric blood supply.

Magnetic resonance angiography in 140 neuropediatric patients

Three-dimensional magnetic resonance angiography (MRA) is a noninvasive technique that images the intracranial arterial vasculature without contrast agents. The suitability of MRA was evaluated for routine use and all children were prospectively studied with conventional MR imaging and time off flight MRA (FISP3D). All MR studies were performed on a 1.5 T-MRA system using a circularly polarized head coil. The study comprised 140 children, ages 3 weeks to 18 years, with different neuropediatric diseases. Major cervical and intracranial arteries were visualized in all age groups. Smaller branches of the supratentorial arteries were identified inconstantly and the number of arteries visualized increased up to the age of 6 years. Sixty-seven children (47%) had normal intracranial vasculature. MRA demonstrated anatomic variations in 21 patients (15%). Twenty-two of 32 children with congenital malformations demonstrated abnormalities of the intracranial vasculature. The diagnostic value of MRA was confirmed in 11 of 12 patients after neonatal stroke and in 3 of 10 children after stroke at older ages. Seven of 18 children with acute hemorrhage demonstrated arteriovenous malformations or an aneurysm on MRA. The correlation with digital subtraction angiographic findings was established in 13 patients. In 9 of 13 children with brain tumor, MRA proved to be diagnostically valuable. MRA proved to be of particular value in the evaluation of the carotid artery following extracorporeal membrane oxygenation therapy. MRA can be used in children of all age groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of three-dimensional phase-contrast magnetic resonance angiography with three-dimensional time-of-flight magnetic resonance angiography in cerebral aneurysms

Magnetic resonance angiography (MRA) can be divided into two types: namely, the phase-contrast (PC) method and the time-of-flight (TOF) method. The purpose of this study is to determine which method is better suited to demonstrate cerebral aneurysms. In a total of 27 cerebral aneurysms confirmed by cerebral angiography, both three-dimensional (3-D) PC and 3-D TOF methods were performed, and the corresponding findings were compared with conventional cerebral angiographic findings. Aneurysm visualization was grouped into three categories: "good" when clearly distinguishable, "fair" if distinguishable when reconstructed, and "poor" if completely undistinguishable. All MRAs were independently interpreted by two neurosurgeons in our institute. Sensitivity was 92.6% when MRA was performed with the TOF method, whereas it was 70.4% when performed with the PC method. In conclusion, the TOF method was more useful for demonstrating the aneurysms than the PC method due to its higher spatial resolution and shorter imaging time.

A ten percent prevalence of asymptomatic familial intracranial aneurysms: preliminary report on 110 magnetic resonance angiography studies in members of 21 Finnish familial intracranial aneurysm families

The population in eastern Finland has been stable for generations, causing a high degree of genetic isolation and providing excellent possibilities for follow-up studies. Of 91 families with familial intracranial aneurysms, 21 were randomly selected for prospective magnetic resonance angiography studies for intracranial aneurysms. Sixteen intracranial aneurysms were detected in 11 asymptomatic family members of a total of 110 studied. The prevalence of intracranial aneurysms among these familial intracranial aneurysm families is 10%, approximately 10 times higher than in the average population. Our findings suggest that family members of familial intracranial aneurysm families should be examined for intracranial aneurysms. Familial intracranial aneurysm may be a genetic disorder.

Magnetic resonance angiography (MRA) of ruptured cerebral aneurysm

The purpose of this study was to evaluate the high resolution magnetic resonance angiography (MRA) as pre-operative angiography for the detection of ruptured cerebral aneurysms. MRA was performed on 1.5 tesla system using the 3-dimensional time of flight (3D-TOF) method. The field of view was 16 cm or 20 cm and matrix size was 192 x 256 or 256 x 512. Twenty patients with ruptured cerebral aneurysms and 35 cases of non-ruptured aneurysms (incidental aneurysm) examined by both conventional angiography and MRA were included in this study. All the ruptured aneurysms were operated on based on the information obtained from conventional angiography and MRA. Aneurysms smaller than 3 mm in size were difficult to visualize on MRA. However, most ruptured aneurysms were clearly visualized because they were generally larger than 3 mm. The image quality of MRA was satisfactory for planning surgery. Screening for non-ruptured cerebral aneurysms using MRA is controversial. However, in ruptured aneurysms larger than 3 mm in size, MRA clearly revealed the aneurysm, and MRA findings were informative enough to plan surgery. It is concluded that this noninvasive examination can be selected as a first-choice examination especially in cases of ruptured aneurysm.

Familial subarachnoid hemorrhage in east Finland, 1977-1990

The familial occurrence of cerebral aneurysms in a defined clinical group of 1150 patients from a defined catchment area was studied. Two or more proven aneurysmal subarachnoid hemorrhage (SAH) patients within the same family were included. Of these 1150 patients, 113 (10%) had a proven familial occurrence of aneurysmal SAH. These 113 patients form 91 SAH families with a total of 203 aneurysm patients. Fifty-four percent of the patients were female, and the mean age in female patients was 49 years and in male patients was 44 years. In 23% of the families, three or more members were identified as having cerebral aneurysms. Middle cerebral artery aneurysms were the most common type (47%). Based on the high incidence (10%) of familial intracranial aneurysms among SAH patients, a prospective study of healthy family members for incidental intracranial aneurysms was performed, with positive findings of 12%.

Preoperative evaluation of giant cell tumors of the radius with magnetic resonance angiography

We report three clinical cases of giant cell tumor of the distal radius in which reconstructions were performed with vascularized fibular grafts. Magnetic resonance angiography, a newer and noninvasive technique, was used in addition to preoperative magnetic resonance imaging. All patients had routine digital subtraction arteriography, with which magnetic resonance angiography compared favorably, demonstrating the carpal arch anatomy and other major vessels at the tumor site. In two patients the trifurcation vessels of both legs were also studied with magnetic resonance angiography before fibular harvest. In one case, the fibula graft was successfully harvested on the basis of the magnetic resonance angiographic findings. In the other case, digital subtraction arteriography had been done to evaluate suspected peripheral vascular disease. In that case magnetic resonance angiography correlated well with the digital subtraction arteriographic study, showing bilateral anterior tibial artery occlusions and patent posterior tibial and peroneal arteries. Magnetic resonance angiography has the potential to replace conventional angiography in preoperative evaluation of upper-extremity tumors.