gms | German Medical Science

Objective: Adequate assessment of the spinal canal with its neuronal structures in patients after complex spinal surgery via standard CT or MRI often remains difficult due to metal-related artefacts. So in many cases more invasive imaging techniques like CT-myelography are necessary. A new promising image modality could be the use of a dual-source CT. This technology allows the reduction of metal-related artefacts and thereby a better evaluation of neural pathologies. This study wanted to evaluate whether the detection of remnant, recurrent or adjacent spinal pathologies could be improved by using a 3rd generation dual-source CT in that patients collective.

Methods: In all patients a 3rd generation dual-source CT was obtained due for follow-up imaging or presenting with new symptoms after cervical or lumbosacral complex spinal surgery. Low tube voltage monoenergetic datasets were calculated in 10 keV intervals (40-190 keV). Software calculated standard CT protocol image (120keV) sets were simultaneously generated for comparative analysis. Image quality was independently assessed by two experienced neurosurgeons through choosing the subjectively best image quality of all performed datasets in comparison to standard CT imaging. A 5-point Likert scale was used regarding overall image quality.

Results: A total of 41 patients after complex spinal surgery could be included. Gender distribution was balanced (20 men and 21 women). Mean age of the patient collective was 61 years (range 30-82y). Most of the patients had previously received lumbar stabilization (25 out of 41; 61%). The remaining 16 patients (39%) previously underwent cervical surgery. The best overall image quality was rated by one neurosurgeon in 39 of the 41 cases and in 40 by the other neurosurgeon. A relevant reduction of metal-related artefacts was seen at higher keV ranges of 170 keV to 190 keV with the maximum artefact reduction seen at 190 keV.

Conclusion: The use of a 3rd generation dual-source CT for follow-up assessment in patients after complex spinal surgery with metal implants seems to be a promising alternative to standard CT or MRI due to the powerful reduction of metal-related artefacts. Therefore extra invasive diagnostic methods could be avoided in the future. Furthermore it can be used as an applicable modality in patients with contraindications for MRI.