MRA review

Familial Intracranial Aneurysms in Saudi Arabia: What Do We Need To Do?

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating event with significant morbidity and mortality. The incidence of SAH might be influenced by environmental factors but genetic predisposition is evolving as an important effector in the risk of development of intracranial aneurysms and rupture of aneurysms. This requires strategies for effective screening of family members at risk of developing such a phenotype, in order to deliver preventive treatment to these target lesions. We discuss the potential for implementing these strategies in the Saudi Arabian health system and the future implications on our care for such a vulnerable group of subjects.

Physical exam myths: listening for carotid artery bruits in stroke patients

When a patient presents to the emergency department with a neurologic deficit and a cerebrovascular event is included in the differential diagnosis, the classic recommendation is to examine the carotid artery and assess for the presence of a bruit. The diagnostic yield and utility of this practice has seldom been called into question. This critical appraisal will review the practice of listening for a carotid artery bruit (CAB) in suspected stroke patients and analyze its clinical utility, including the sensitivity and specificity of a CAB for detecting a significant lesion and the potential impact a CAB may have on the investigation and disposition of such patients.

[Asymptomatic carotid disease--early detection]

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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.

Diagnostic issues in migraine

Headache poses diagnostic challenges to the clinician for many reasons. It is an extremely common complaint, and may be associated with acute illness or serious pathology such as brain tumor or cerebral aneurysm. However, the majority of patients experiencing recurrent headache in the population suffer either from a variant of tension-type headache or migraine. Because migraine is more likely to be disabling, it becomes the most likely diagnosis for any patient presenting with recurrent headache interfering with function. Although the diagnostic criteria developed by the International Headache Society in 1998 are useful as a guide, migraine may be more readily recognized in a clinical setting by its consideration at the top of the differential for patients presenting with recurrent headache. This article reviews the standard diagnostic criteria for migraine, while also addressing the primary and secondary headache syndromes that may be considered in a differential diagnosis. The indications and roles for specific investigative procedures such as neuroimaging are reviewed. Specific emphasis is placed on the clinical recognition of migraine in the context of an assortment of headache conditions.

Pediatric extracranial applications of MR angiography

Extracranial magnetic resonance angiography (MRA) was performed in 20 children to evaluate for various arterial and venous conditions. Time-of-flight and phase-contrast angiograms were constructed using a maximal-intensity-projection algorithm. The accuracy of MRA was comparable to Doppler ultrasound (n = 12) and conventional angiography (n = 3). MRA could provide an excellent mapping of patent (including collaterals) versus thrombosed vessels at sites not evaluated or inaccessible by sonography. Limitations included assessment of small and/or tortuous vessels, severely stenotic lesions, and very slow flow.

Use of three-dimensional segmented FLASH sequence with magnetization transfer contrast to improve Gd-DTPA-enhanced intrahepatic MR portography

Twenty healthy volunteers underwent gadopentetate dimeglumine (gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA))-enhanced MR angiography (MRA) using three-dimensional-segmented fast low angle shot images (FLASH) with magnetization transfer contrast (MTC) pulses. MRA was obtained at 75 seconds (early phase) and 135 seconds (late phase) after bolus injection of Gd-DTPA (MTC+ group) during one period of breath-holding. Within 1 week. MRA without MTC was performed under the same scanning conditions. Visualization of intrahepatic portal branches with these methods was compared in both phases. Portal vein-liver contrast-to-noise ratios were significantly higher in the MTC+ group in both phases. For third- and fourth-order portal branches, visualization was significantly better in the MTC+ group in both phases. Use of three-dimensional-segmented FLASH shortened acquisition time and facilitated imaging during breath-holding and also reduced whole-body average specific absorption rate values. Visualization of intrahepatic portal vein branches was improved by MTC pulses, and effective imaging time was prolonged.

Migraine and pregnancy

Migraine and tension-type headache are primary headache disorders that occur during pregnancy. Migraine sometimes occurs for the first time with pregnancy. Most migraineurs improve while pregnant; however, migraine often recurs postpartum. Some disorders that produce headache, such as stroke, cerebral venous thrombosis, eclampsia, and SAH, occur more frequently during pregnancy. Diagnostic testing serves to exclude organic causes of headache, to confirm the diagnosis, and to establish a baseline before treatment. If neurodiagnostic testing is indicated, the study that provides the most information with the least fetal risk is the study of choice. Although drugs are used commonly during pregnancy, there is insufficient knowledge about their effects on the growing fetus. Most drugs are not teratogenic. Adverse effects, such as spontaneous abortion, development defects, and various postnatal effects, depend on the dose and route of administration and the timing of the exposure relative to the period of fetal development. Although medication use should be limited, it is not absolutely contraindicated in pregnancy. In migraine, the risk of status migrainosus may be greater than the potential risk of the medication use to treat the pregnant patient. Nonpharmacologic treatment is the ideal solution; however, analgesics, such as acetaminophen and narcotics, can be used on a limited basis. Preventive therapy is a last resort.

Diagnosis of spinal arteriovenous malformations by MRI at 1.0 T

Eight patients were examined by magnetic resonance imaging (MRI) at 1.0 T; seven had an angiographically proved spinal intradural arteriovenous malformation and one had a hemangioblastoma of the spinal cord. Myelography was also performed in five and computed tomography (CT) in four patients. The clinical and radiological findings are presented. MRI revealed the location and extent of the lesion. Myelomalacia, edema, and hematomyelia were demonstrated in three patients. In our opinion MRI is the method of choice for the diagnosis of spinal arteriovenous malformation and facilitates spinal angiography, whereas myelography and CT do not provide any further information.

Use of magnetization transfer contrast to improve single breath-hold three-dimensional MR-portography with bolus injection of gadopentetate dimeglumine: a preliminary report

We investigated whether better visualization of the intrahepatic portal system could be obtained by adding magnetization transfer contrast (MTC) to three-dimensional MR portography (3D-MRP). In 15 healthy volunteers, 3D fast low-angle shot images combined with an off-resonance pulse were obtained after bolus injection of gadopentetate dimeglumine during one period of breath-holding. Within 1 week after injection, MR images without MTC were obtained using the same scanning condition. MRPs with and without the MTC pulse were compared quantitatively and qualitatively. The contrast-to-noise ratio of the portal vein-liver was significantly higher in the group imaged with the addition of MTC. Qualitatively, the use of MTC improved peripheral portal branch depiction on maximum-intensity projection images. Even when the MTC pulse was added to the conventional method of 3D data collection, it was possible to obtain images within one period of breath-holding. In conclusion, the use of MTC can substantially enhance the quality of 3D-MRPs.

Single breath-holding three-dimensional magnetic resonance portography with bolus injection of Gd-DTPA in subjects with normal liver: a comparison with two-dimensional time-of-flight technique

Two-dimensional time-of-flight (2D-TOF) magnetic resonance (MR) portography tends to produce general image degradation owing to the phase discrepancy caused by multiple breath-holding. To solve this problem, three-dimensional (3D)-MR portographies were reconstructed from image data acquired with a bolus injection of Gd-DTPA with single breath-holding in 20 subjects with normal liver function. 2D-TOF MR portographies were obtained beforehand for the comparison. All the images were displayed in a cine mode for the two MR angiographic techniques. Visualization was assessed as positive when the vessel was visualized without disruption. 3D-MR portography produced a positive rate of over 80% for all but the left first-order branch. With the 2D-TOF techniques, however, only the portal trunk and left second-order branches were visualized at this rate. The positive rate for most portal branches was significantly higher with 3D-MR portography than with the 2D-TOF technique. In conclusion, 3D-MR portography makes it possible to depict the portal venous system without disruption using a short measurement time with single breath-holding and has the potential to become a powerful method for abdominal MR angiography.