Magnetic resonance imaging in the diagnosis of brain arteriovenous malformations and in the evaluation of the results of stereotactic radiosurgery (review)

2021 ◽  
Vol 23 (1) ◽  
pp. 135-145
Author(s):  
A. S. Tokarev ◽  
S. A. Chuvilin ◽  
M. V. Neznanova
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Stereotactic Radiosurgery ◽  
Arteriovenous Malformations ◽  
Endovascular Embolization ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Factors Affecting ◽  
Risk Of Rupture ◽  
High Degree

Arteriovenous malformations (AVM) are quite rare, but they are dangerous pathology due to the risk of rupture and intracranial hemorrhage, which leads to disability. This review enlights the epidemiology of AVM and their symptoms, current methods of diagnostics and treatment as well as prognosis and treatment outcomes. Nowadays microsurgical removal, endovascular embolization, stereotactic radiosurgery and combination of these methods are used in clinical practice for AVMs treatment. Stereotactic radiosurgery is a highly effective non-invasive technique resulting in high degree of AVM obliteration with low risk of complications. The results of magnetic resonance imaging usage in assessing the degree of obliteration and the development of post-radiation complications are presented in this article. The optimization of magnetic resonance imaging algorithm is necessary for determination of statistically significant factors affecting the obliteration process.

scholarly journals Sensitivity of Magnetic Resonance Imaging in the Detection of Colorectal Liver Metastases

2008 ◽  
Vol 90 (1) ◽  
pp. 25-28 ◽  
Author(s):  
S Blyth ◽  
A Blakeborough ◽  
M Peterson ◽  
IC Cameron ◽  
AW Majeed
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Liver Metastases ◽  
Colorectal Liver Metastases ◽  
Imaging Modality ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
High Degree

INTRODUCTION The aim of this study was to evaluate the sensitivity of magnetic resonance imaging (MRI) in the detection of colorectal liver metastases. PATIENTS AND METHODS Pre-operative MRI scanning of the liver was performed by a single radiologist and the size and number of definite liver metastases were recorded. Patients then underwent hepatectomy with routine intra-operative ultrasonography (IOUS) and resected specimens were sent for histopathology. Pathology findings were compared with those of MRI scans to determine the sensitivity of this imaging modality. Exclusions were patients undergoing hepatic resection more than 4 weeks after the MRI scan, those undergoing chemotherapy at the time of the scan, and those with conglomerate unilobar metastases. RESULTS Complete data were available for 84 patients. There was total agreement between MRI, IOUS and histology in 79 patients (101 metastases). MRI missed 5 metastases in 5 patients that were found on IOUS (or palpation of superficial lesions) and subsequently confirmed by histological examination. These measured 5 mm or less (4 patients) and 7 mm (one patient). The sensitivity of MRI in the detection of colorectal liver metastases was thus 94% for all lesions and 100% for lesions 1 cm or larger in diameter. CONCLUSIONS MRI of the liver is a non-invasive technique with an extremely high degree of sensitivity in the detection of colorectal liver metastases and should be considered as the ‘gold standard’ in the pre-operative imaging of these patients.

Multisession CyberKnife Radiosurgery for Intramedullary Spinal Cord Arteriovenous Malformations

Neurosurgery ◽  
2006 ◽  
Vol 58 (6) ◽  
pp. 1081-1089 ◽  
Author(s):  
John Sinclair ◽  
Steven D. Chang ◽  
Iris C. Gibbs ◽  
John R. Adler
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spinal Cord ◽  
Magnetic Resonance ◽  
Arteriovenous Malformations ◽  
Conus Medullaris ◽  
Spinal Angiography ◽  
Resonance Imaging ◽  
Intramedullary Spinal Cord ◽  
Cyberknife Radiosurgery

Abstract OBJECTIVE: Intramedullary spinal cord arteriovenous malformations (AVMs) have an unfavorable natural history that characteristically involves myelopathy secondary to progressive ischemia and/or recurrent hemorrhage. Although some lesions can be managed successfully with embolization and surgery, AVM size, location, and angioarchitecture precludes treatment in many circumstances. Given the poor outlook for such patients, and building on the successful experience with radiosurgical ablation of cerebral AVMs, our group at Stanford University has used CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS) to treat selected spinal cord AVMs since 1997. In this article, we retrospectively analyze our preliminary experience with this technique. METHODS: Fifteen patients with intramedullary spinal cord AVMs (nine cervical, three thoracic, and three conus medullaris) were treated by image-guided SRS between 1997 and 2005. SRS was delivered in two to five sessions with an average marginal dose of 20.5 Gy. The biologically effective dose used in individual patients was escalated gradually over the course of this study. Clinical and magnetic resonance imaging follow-up were carried out annually, and spinal angiography was repeated at 3 years. RESULTS: After a mean follow-up period of 27.9 months (range, 3–59 mo), six of the seven patients who were more than 3 years from SRS had significant reductions in AVM volumes on interim magnetic resonance imaging examinations. In four of the five patients who underwent postoperative spinal angiography, persistent AVM was confirmed, albeit reduced in size. One patient demonstrated complete angiographic obliteration of a conus medullaris AVM 26 months after radiosurgery. There was no evidence of further hemorrhage after CyberKnife treatment or neurological deterioration attributable to SRS. CONCLUSION: This description of CyberKnife radiosurgical ablation demonstrates its feasibility and apparent safety for selected intramedullary spinal cord AVMs. Additional experience is necessary to ascertain the optimal radiosurgical dose and ultimate efficacy of this technique.

Magnetic resonance imaging of spinal arteriovenous malformations

1987 ◽  
Vol 66 (6) ◽  
pp. 830-834 ◽  
Author(s):  
John L. Doppman ◽  
Giovanni Di Chiro ◽  
Andrew J. Dwyer ◽  
Joseph L. Frank ◽  
Edward H. Oldfield
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Arteriovenous Malformations ◽  
High Signal ◽  
Resonance Imaging ◽  
Content Type ◽  
Spinal Arteriovenous Malformations ◽  
Magnetic Resonance Imaging Mri ◽  
Spinal Avm ◽  
Fine Print

✓ Magnetic resonance imaging (MRI) was performed on 12 patients with spinal arteriovenous malformations (AVM's). Six lesions were intramedullary, five were dural, and one was in a posterior extramedullary location. Serpentine filling defects similar to the classic myelographic findings were demonstrated within the high-signal cerebrospinal fluid on T2-weighted coronal scans. The intramedullary nidus was identified by MRI as an area of low-signal intensity within the cord in all six intramedullary AVM's. Neither the dural nor the posterior extramedullary lesions showed intramedullary components. It is concluded that MRI may noninvasively provide the initial diagnosis of a spinal AVM and distinguish intramedullary from dural and extramedullary lesions.

scholarly journals Evaluation of Rectal and Skin Temperature Variations of Anesthetised Dogs Undergoing Magnetic Resonance Imaging Diagnosis

2019 ◽  
Vol 76 (2) ◽  
pp. 209
Author(s):  
Andra DEGAN ◽  
Ruxandra TUDOR ◽  
Ruxandra COSTEA ◽  
Dragoș BÎRȚOIU ◽  
Mihai SĂVESCU ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
General Anesthesia ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Thermal Imaging ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Temperature Variations ◽  
Before And After

General anesthesia produces different degrees of central nervous depression and changes in the peripheral circulation, therefore affecting the patient’s thermoregulatory mechanism. Moreover, the lack of proper, specially designed equipment for magnetic resonance imaging (MRI) environment monitoring can represent a challenge for the anesthetist. We examined the temperature variations correlated with different anesthetic protocols in dogs that underwent general anesthesia in order to evaluate changes in rectal and distal extremities temperature, before and after anesthesia. This study was conducted at the Faculty of Veterinary Medicine in Bucharest, on 21 dogs that were divided in 3 groups depending on the anesthetic protocol used. First group (B) received butorphanol (0.2 mg/kg, intravenously IV), second group (BK) had butorphanol (0.2 mg/kg) and a low dose of ketamine (2 mg/kg) IV, and group 3 (BM) was premedicated with butorphanol (0.2 mg/kg) and midazolam (0.2 mg/kg) IV. All patients were induced with propofol i.v. (3.24±0.68), intubated and maintained with isoflurane and oxygen. We determined rectal temperature before and right after the end of anesthesia with a digital thermometer and distal extremities temperature with the use of a thermal imaging camera attached to a smartphone. There was no significant difference between the rectal temperature before and after anesthesia within the 3 groups. Patients in group BK had a significant change in skin temperature at the end of anesthesia in all limbs (from 310C to 29.8 0C, p=0.008 and from 31 0C to 29.70C, p=0.009), respectively). Temperature variations were presented before and at the end of anesthesia, for all the groups especially at skin level. This study revealed that mobile thermal imaging represents a non-invasive technique that is helpful in assessing real time temperature changes in patients undergoing general anesthesia.

scholarly journals Dilated Virchow–Robin Spaces Mimicking a Brainstem Arteriovenous Malformation

2017 ◽  
Vol 08 (02) ◽  
pp. 291-293 ◽  
Author(s):  
Thomas J. Buell ◽  
Arjun Ramesh ◽  
Dale Ding ◽  
Daniel M. S. Raper ◽  
Ching-Jen Chen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Arteriovenous Malformation ◽  
Arteriovenous Malformations ◽  
Pulse Sequences ◽  
Resonance Imaging ◽  
Unique Case ◽  
Cystic Neoplasms ◽  
Imaging Characteristics ◽  
Magnetic Resonance Imaging Mri

ABSTRACTVirchow–Robin spaces (VRS) are ubiquitous and commonly observed as the resolution of magnetic resonance imaging (MRI) continues to improve. The function of VRS and the etiology of their dilation is still a subject of research. Diagnosing dilated VRS (dVRS) can be challenging because they may appear similar to other pathologies such as cystic neoplasms, infectious cysts, and even arteriovenous malformations (AVMs) on certain MRI pulse sequences. We reported a unique case of brainstem dVRS mimicking an AVM. Furthermore, the extensive pontine involvement of our patient’s lesion is rarely described in neurosurgical literature. Understanding the imaging characteristics of dVRS is critical to accurately diagnose these lesions and avoid unnecessary tests and procedures.

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