ngiography of Neurovascular Lesions in Pediatric Patients Pediatric Imaging Pictorial Essay M E E N T U R I L I M G I N G JR 2006; 186:75 84 0361 803X/06/1861 75 merican Roentgen Ray Society Y O John M. Racadio 1 radley L. Fricke laise V. Jones Lane F. onnelly F Keywords: head and neck imaging, interventional radiology, neuroimaging, pediatric imaging, pediatric radiology OI:10.2214/JR.04.1595 Received October 12, 2004; accepted after revision January 31, 2005. 1 epartment of Radiology, incinnati hildren s Hospital Medical enter, 3333 urnet ve., incinnati, OH 45229-3039. ddress correspondence to J. M. Racadio (john.racadio@cchmc.org). Three-imensional Rotational ngiography of Neurovascular Lesions in Pediatric Patients OJETIVE. In this pictorial essay, we review the 3 rotational angiography (R) studies of six pediatric patients; in these cases, the information obtained with 3 R was uniquely beneficial in diagnosis and treatment planning. ONLUSION. Three-dimensional R is an excellent tool for the evaluation of a number of intracranial lesions in pediatric patients: There is less total radiation exposure from a single rotational run than from T or a conventional angiography examination that involves more than one view and the study is quick, with data acquisition requiring less than 8 sec and fully rendered 3 reconstructions generated within 180 sec. he accurate depiction of intracranial vascular lesions and related T anatomy with imaging is essential for appropriate clinical management. Historically, these lesions have been evaluated with catheter angiography using 2 digital subtraction techniques. However, overlapping vessels and large areas of opacification can obscure vascular relationships, and complex vascular structures often require multiple contrast injections for adequate evaluation, increasing radiation dose and risk of nephrotoxicity and volume overload from increased contrast load [1]. Minimizing the radiation dose is Fig. 1 Vein of Galen aneurysmal malformation in 8-month-old female infant., nteroposterior angiogram with injection in left vertebral artery shows vein of Galen aneurysmal malformation (arrows) with primary supply from left posterior choroidal artery (arrowheads)., nteroposterior gradient-rendered view of 3 rotational angiography (R) shows precise location and orientation of feeding artery (arrows) to malformation. (Fig. 1 continues on next page) JR:186, January 2006 75
E Fig. 1 (continued) Vein of Galen aneurysmal malformation in 8-month-old female infant., Two views of shaded-surface cut-away 3 R show flow into aneurysmal malformation through feeding vessel (arrows) and precise diameter of feeding vessel in preparation for coil embolization., Two views from volume-rendered 3 R obtained 16 months after partial embolization. Note previous area of embolization (arrows), as determined with conventional angiography, and new vessel (arrowheads) feeding aneurysmal malformation. ut-away feature of 3 R workstation used to locate exact site of feeding vessel enters aneurysmal malformation from the left. E, Oblique view of shaded-surface reconstruction from left vertebral artery injection after second embolization. Previously placed embolization coils (arrows) are gray with residual right-sided posterior choroidal arterial feeder (arrowheads) inferior and lateral to coil mass. particularly important in children because of the relatively increased lifetime cancer risk as compared with adults [2]. The use of R in the evaluation of intracranial aneurysms was first described in 1972 [3] and was advanced into clinical practice in 1975 [4]. The benefits of 3 digital reconstruction of rotational data were reported in animal and in vitro studies in 1997 [5] and clinically in 1998 [6]. The reports also described the usefulness of 3 R in the evaluation of intracranial arteriovenous malformations and cerebral aneurysms in adults [7]. However, there has been no published literature describing the evaluation of 76 JR:186, January 2006
ngiography of Neurovascular Lesions in Pediatric Patients Fig. 2 2-month-old female infant with arteriovenous fistula from middle cerebral artery to vein of Labbé., xial T2-weighted MR image shows enlarged transverse sinus (arrows) secondary to arteriovenous fistula., nteroposterior conventional angiogram shows dilated transverse sinus (arrows)., nteroposterior gradient-rendered view of 3 rotational angiography (R) shows arteriovenous fistula from middle cerebral artery (arrows) to vein of Labbé (arrowheads). Three-dimensional R was performed immediately before coil embolization., Medial gradient-rendered view of 3 R shows arteriovenous fistula from middle cerebral artery (arrows) to vein of Labbé (arrowheads). (Fig. 2 continues on next page) JR:186, January 2006 77
Fig. 2 (continued) 2-month-old female infant with arteriovenous fistula from middle cerebral artery to vein of Labbé. E, Posterior craniocaudal oblique volume-rendered view of 3 R shows arteriovenous fistula from middle cerebral artery (arrows) to vein of Labbé (arrowheads). On the basis of 3 R images, chronology of coil embolization was planned; patient underwent two scheduled rounds of embolization with obliteration of arteriovenous fistula. E Fig. 3 rteriovenous malformation (VM) of mandible in 10-year-old girl who presented with massive hemorrhage after attempted extraction of impacted molar tooth., oronal contrast-enhanced T1-weighted MR image shows enhancement within left mandible (arrows) and enlarged draining vein (arrowheads), indicating high-flow VM., Lateral oblique projection of volume-rendered MR angiography shows dilated vein draining from VM (arrows) in mandible, with arterial supply from internal maxillary artery (M) and lingual and facial arteries (arrowheads). (Fig. 3 continues on next page) 78 JR:186, January 2006
ngiography of Neurovascular Lesions in Pediatric Patients neurovascular lesions in pediatric patients with 3 R to our knowledge. In this pictorial essay, we review 3 R studies in six children in which the information obtained with 3 R was uniquely beneficial in diagnosis and treatment planning. Three-imensional R Technique ll patients underwent 3 R on an Integris llura iplane unit (Philips Medical Systems). Three-dimensional images were reconstructed from data collected using a 180 rotational arc. uring the rotational examination, contrast material was hand-injected into the vascular territory of interest. total of 120 images were obtained in this arc. Radiation exposure, as measured with a pelvic phantom, was found to be 4.4 Gy/cm 2 when 120 images were obtained. This compares to a total dose of 9.6 Gy/cm 2 resulting from two angiographic series obtained in the anteroposterior and lateral planes. Three-dimensional reconstructions Fig. 3 (continued) rteriovenous malformation (VM) of mandible in 10-year-old girl who presented with massive hemorrhage after attempted extraction of impacted molar tooth., Medial view of volume color-rendered 3 rotational angiography from injection of left external carotid artery shows supply to VM from lingual and facial arteries (arrows) and from palatal branches of internal maxillary artery (arrowheads)., Lateral view of same reconstruction as shows VM (arrows) and markedly dilated draining vein (arrowheads). are performed in 180 sec and are available for analysis and manipulation on a dedicated 3 R workstation. linical Utility Vascular Malformations Three-dimensional imaging is useful in defining both intracranial and extracranial vascular malformations. The configuration of their feeding vessels, transition points, and draining veins is shown [7]. In children, these malformations are typically high-flow, with complex anatomy of both arterial feeders and venous drainage. The 3 R data set enables highly detailed anatomic analysis of arterial supply to malformations so that decisions regarding microcatheter choice, angle of approach, and chronology of embolization can be made with a single arteriographic run (Fig. 1). This information aids in determining the type of coils or embolic material appropriate for endovascular therapy and for assessment of potential open surgical treatment (Fig. 2). In patients with complex malformations, 3 R volume color rendering can be used to show the transition from arterial to venous components (Fig. 3). neurysms In the evaluation of intracranial aneurysms, 3 R allows detailed information concerning the aneurysmal neck, including diameter, morphology, and orientation of the feeding arteries and surrounding vessels [7]. These characteristics are essential to determine the appropriate type and size of endovascular coils for embolization. The 3 R workstation offers a virtual 3 cut-away option, which enables the radiologist to visualize the exact location, orientation, and size of the feeding vessels, even in a highly complex vascular web. Three-dimensional reconstruction of rotational data generates images that can be visualized in any plane, which is beneficial for treatment planning. single rotation replaces multiple static views that would be necessary to otherwise de- JR:186, January 2006 79
fine aneurysms and, as previously mentioned, can decrease total radiation dose. The detailed real-time analysis afforded by 3 R has established its usefulness in adults, and this experience can be directly applied to the less frequently encountered pediatric patient with intracranial aneurysm. Tumors Three-dimensional R also has been shown to be useful in evaluating the vascular anatomy of intracranial neoplasms for surgical planning or preoperative embolization. The 3 R data set enables delineation of the exact vascular supply to the tumor, providing the neurosurgical team with an ideal surgical approach and decreasing the risk of encountering unexpected vascular anatomy in the operating suite (Fig. 4). Fig. 4 Meningioma in 7-year-old boy., xial contrast-enhanced T1-weighted MR image shows meningioma (arrows) in left parietal lobe is impinging on branches of middle cerebral artery in sylvian fissure., Lateral oblique volume-rendered view of 3 rotational angiography (R) from left common carotid arterial injection shows external carotid artery (arrowheads), internal carotid artery (I), and vessel paucity (arrows) in area of meningioma. (Fig. 4 continues on next page) Trauma MT is a quick and readily available imaging technique to evaluate trauma patients. However, certain lesions can produce a great amount of artifact on T images, and when in close proximity to vessels or vital tissues, it may be difficult to assess these structures for injury. oth conventional angiography and 3 R can be used as an adjunct for evaluation of these patients. The rotational angiogram itself takes seconds to acquire, with only a 180-sec lag time for reconstruction of the 3 image. ynamic information can also be obtained from the 2 rotational raw data. Whereas the 3 reconstruction can be subject to the same metallic artifact that compromises T, the 2 data are unencumbered and give the clinician excellent 180 diagnostic images to make a well-informed and confident decision (Fig. 5). Three-dimensional R is also useful in delineating incidental findings detected on posttraumatic imaging evaluation (Fig. 6). onclusion Three-dimensional R is an excellent tool for the evaluation of a number of intracranial lesions in children: There is less total radiation exposure from a single rotational run than from T or a conventional angiography examination that involves more than one view and the study is quick, with data acquisition requiring less than 8 sec and fully rendered 3 reconstructions generated within 180 sec. y eliminating multiple oblique angiographic injections, the overall contrast load is 80 JR:186, January 2006
ngiography of Neurovascular Lesions in Pediatric Patients E Fig. 4 (continued) Meningioma in 7-year-old boy., nteroposterior shaded-surface views of 3 R without (left image) and with (right image) spherical volume measurement of tumor (green) show location and mass effect of meningioma. Internal carotid artery (arrows) and superficial temporal branch of external carotid artery (arrowheads) are shown., Lateral oblique shaded-surface view of 3 R depicts spherical volume measurement of tumor (green). Internal carotid artery (arrows) and superficial temporal branch of external carotid artery (arrowheads) are shown. E, Lateral shaded-surface view of 3 R with spherical volume measurement (green). Internal carotid artery (arrows) and superficial temporal branch of external carotid artery (arrowheads) are shown. Three-dimensional R enables neurosurgical team to delineate ideal surgical approach that would identify middle cerebral artery branches at risk before encountering them in operating suite. JR:186, January 2006 81
Fig. 5 10-year-old boy with gunshot injury to neck., xial T image shows left common carotid artery (arrows) near bullet., xial T image illustrates that visualization of left common carotid artery is compromised by metallic artifact secondary to bullet., Medial posterior oblique shaded-surface view of 3 rotational angiography (R) shows bullet near common carotid artery. Note artifactual defect suggesting spasm or stenosis of common carotid artery adjacent to bullet., Medial anterior oblique view from 2 R shows bullet does not contact common carotid artery, which is intact. Surgical exploration and anticoagulation therapy were withheld, and patient recovered. 82 JR:186, January 2006
ngiography of Neurovascular Lesions in Pediatric Patients decreased when compared with conventional angiography or T. Multiple 3 reconstruction renderings and options available at the 3 R workstation allow the radiologist to better understand complex intracranial lesions in real time. Three-dimensional R will continue to benefit pediatric patients with complex intracranial lesions in the diagnosis, evaluation, and determination of the most effective treatment strategies. References 1. Sugahara T, Yukunori K, Nakashima K, Hamatake Fig. 6 alcified lesion near vertebral artery in 15-year-old boy who underwent T for evaluation of football injury., xial T image shows incidental calcified lesion (arrows) near left vertebral artery (arrowheads)., MR angiography image shows left vertebral artery (arrows) but does not exclude vessel injury secondary to artifact and irregular appearance of vessel wall., nteroposterior shaded-surface view of 3 rotational angiography (R) shows vertebral artery (arrows) without evidence of vascular lesion., Medial shadedsurface view of 3 R shows intact vertebral artery (arrows). Threedimensional R was performed and showed no evidence for dissection or pseudoaneurysm. Lesion has remained stable and is presumed unrelated to trauma at presentation. S, Honda S, Takahashi M. omparison of 2 and 3 digital subtraction angiography in evaluation of intracranial aneurysms. m J Neuroradiol 2002; 23:1545 1552 2. onnelly LF, Emery KH, rody S, et al. Minimizing radiation dose for pediatric body applications of single-detector helical T: strategies at a JR:186, January 2006 83
FOR YOUR INFORMTION large children s hospital. JR 2001; 176:303 306 3. ornelis G, ellet, van Eygen, Roisin P, Libon E. Rotational multiple sequence roentgenography of intracranial aneurysms. cta Radiol iag (Stockh) 1972; 13:74 76 4. Voigt K, Stoeter P, Petersen. Rotational cerebral roentgenography. I. Evaluation of the technical procedure and diagnostic application with model studies. Neuroradiology 1975; 10:95 100 5. Fahrig R, Fox J, Lownie S, Holdsworth W. Use of a -arm system to generate true three-dimensional computed rotational angiograms: preliminary in vitro and in vivo results. m J Neuroradiol 1997; 18:1507 1514 6. Heautot JF, habert E, Gandon Y, et al. nalysis of cerebrovascular diseases by a new 3-dimensional computerized X-ray angiography system. Neuroradiology 1998; 40:203 209 7. Klucznik RP. urrent technology and clinical applications of three-dimensional angiography. Radiol lin North m 2002; 40:711 728 For the convenience of JR authors, a standardized form requesting permission to reprint from other publications is now available via the RRS Web site at www.ajronline.org/misc/ifora.shtml. Your computer system must have version 3.0 or later of dobe crobat Reader. 84 JR:186, January 2006