RESUMO
A three-dimensional image registration technique for CT and MR studies of the cervical spine was evaluated for feasibility and efficacy. Registration by means of external fiducial markers was slightly more accurate than registration by anatomic landmarks. The interrelationships between bony (eg, neural foramina) and soft tissue structures (eg, nerve roots) in the cervical spine were more conspicuous on registered images than on conventional displays. Registration of CT and MR images may be used to examine more precisely the relationships between bony and soft tissue structures of the cervical spine.
Assuntos
Vértebras Cervicais/patologia , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Valores de Referência , Sensibilidade e EspecificidadeRESUMO
Magnetic resonance (MR) imaging of the cervical spine with axial, low flip angle three-dimensional (3D) gradient-echo sequences is limited by long acquisition times and also by increased sensitivity to extrinsic and intrinsic magnetic field inhomogeneity, magnetic susceptibility differences, chemical shifts, and cerebrospinal fluid pulsatility. We attempted to assess the performance of gadolinium-enhanced, magnetization transfer (MT) prepulsed 3D fast gradient-echo sequences in demonstrating spondylotic changes of the cervical spine. Twenty patients with known cervical spine spondylosis were prospectively imaged in the axial plane using two gradient-echo-based MR techniques: 3D fast field echo (FFE) and gadolinium-enhanced, MT prepulsed, segmented turbo field echo (TFE). An average of 58 neural foramina on the 3D FFE images and 47 neural foramina on the contrast-enhanced TFE images were judged to be narrowed. The degree of neural foraminal narrowing was significantly less on the contrast-enhanced TFE images compared with the FFE images (P <0.001). Contrast-enhanced, MT prepulsed, segmented 3D TFE MR imaging has potential for ameliorating some of the limitations encountered in the more widely used gradient-echo techniques.
Assuntos
Vértebras Cervicais/patologia , Imagem Ecoplanar , Processamento de Imagem Assistida por Computador , Osteofitose Vertebral/diagnóstico , Meios de Contraste , Feminino , Análise de Fourier , Gadolínio DTPA , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes de Compressão Nervosa/diagnóstico , Raízes Nervosas Espinhais/patologiaRESUMO
Contrast-bolus tracking in the carotid bifurcation was accomplished using an MR angiographic technique with a 3D turbo field-echo readout (TR/TE = 6/3, flip angle = 50 degrees) modified by a keyhole scheme. Optimal visibility of the contrast bolus was achieved by digital subtraction from a reference volume. This technique reliably time-resolves the carotid arteries from the jugular veins.
