Postoperative Spine

Postoperative Bildgebung der Wirbelsäule

Die Bildgebung der postoperativen Wirbelsäule hat im Wesentlichen zwei Aufgaben: Sie dient der Kontrolle des operativen Erfolgs und der Identifikation von Komplikationen. Dafür stehen die konventionelle Röntgenaufnahme, Computertomographie (CT), Myelographie und Magnetresonanztomographie (MRT) zur Verfügung. Unter Berücksichtigung der präoperativen Situation, der durchgeführten Operation und der postoperativen Beschwerdekonstellation ist es Aufgabe der Radiologinnen und Radiologen, die passende Modalität für eine suffiziente Diagnostik zu wählen. Insbesondere der Zustand nach Implantation von Fremdmaterial bedeutet eine technische Herausforderung im Rahmen der Bildakquisition. In der Befundung sehen sich die Radiologinnen und Radiologen mit der Aufgabe konfrontiert, zwischen natürlichen, zu erwartenden postoperativen Veränderungen und relevanten Komplikationen zu differenzieren. Ein reger Austausch mit Patientinnen und Patienten und zuweisenden Klinikerinnen und Klinikern ist dabei unerlässlich. Insbesondere klinische Hinweise auf einen Infekt, neue oder deutliche progrediente neurologische Ausfallserscheinungen und das Konus-Kauda-Syndrom erfordern eine zeitnahe Diagnosestellung, um eine rasche Therapieeinleitung zu gewährleisten.

Evaluation of craniocervical pseudomeningoceles with three-dimensional T2-SPACE sequence at 3T

BACKGROUND

Pseudomingocele is a postoperative fluid collection adjacent to the dural membrane. The distinction of pseudomeningocele from other postoperative collections is very important.

PURPOSE

To show the efficacy of three-dimensional (3D) T2-weighted sampling perfection with application-optimized contrasts using a different flip-angle evolution (SPACE) magnetic resonance imaging (MRI) sequence in the diagnosis of pseudomeningocele in which conventional MRI sequences may be insufficient.

MATERIAL AND METHODS

A total of 10 patients were included in the study. All of these patients also had 3D T2-SPACE high-resolution volumetric MR image in addition to conventional cervical and cerebral MR sequences. All MR examinations were reviewed by two neuroradiologists.

RESULTS

Pseudomeningocele neck was shown in six patients by both conventional sequences and SPACE sequence. In two patients, the neck was only shown in the SPACE sequence. Four pseudomeningocele necks were shown to have flow void with both conventional sequences and SPACE sequence. Flow void could only be demonstrated by SPACE sequence in two patients.

CONCLUSION

A T2-SPACE sequence can show the presence of pseudomeningocele neck and flow void even in cases where conventional MRI cannot show, thus contributing to the diagnosis of pseudomeningocele. Therefore, especially in postoperative imaging, the T2-SPACE sequence may be included in routine sequences to make the differential diagnosis correctly.

Differentiating epidural fibrosis from disc herniation on contrast-enhanced and unenhanced MRI in the postoperative lumbar spine

OBJECTIVE

To determine diagnostic confidence and inter-observer/intra-observer agreement in differentiating epidural fibrosis from disc herniation and lumbar spinal stenosis parameters on magnetic resonance images (MRI) in postoperative lumbar spines with (Gad-MRI) and without (unenhanced MRI) intravenous gadolinium-based contrast agent.

SUBJECTS AND METHODS

N = 124 lumbar spine MRI examinations of four groups were included: 1-6 months, 7-18 months, 19-36 months, more than 37 months between lumbar spine surgery and imaging. Two radiologists evaluated Gad-MRI and unenhanced MRI: diagnostic confidence was determined as confident or unconfident. Inter-observer and intra-observer agreement were assessed in differentiating epidural fibrosis from disc herniation and for lumbar spinal stenosis parameters on MRI. Fisher's exact test and Cohen's kappa served for statistics.

RESULTS

Diagnostic confidence in differentiating epidural fibrosis from disc herniation was significantly higher on Gad-MR images compared with unenhanced MRI at 1-18 months for observer 1 and at 1-6 months postoperatively for observer 2 (p values: 0.01-0.025). Inter-observer agreement at 1-6 months postoperatively for identification of epidural fibrosis was higher on Gad-MRI (kappa values: 0.53 versus 0.24). Inter-observer and intra-observer agreement for identification of disc herniation and for assessment of lumbar spinal stenosis parameters revealed inconsistent data, without a trend for higher inter-observer or intra-observer agreement on Gad-MRI compared with unenhanced MRI (kappa values: 0.17-0.75).

CONCLUSION

Gad-MR images compared with unenhanced MRI improved diagnostic confidence and agreement in differentiating epidural fibrosis from disc herniation for both observers in the first 6 months and for one observer in the first 18 months after lumbar spine surgery. After 18 months, Gad-MR images compared with unenhanced MRI did neither improve confidence nor agreement.