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. 2022 Oct;43(10):1539-1543.
doi: 10.3174/ajnr.A7628. Epub 2022 Sep 8.

Utility of Dual-Energy CT to Improve Diagnosis of CSF Leaks on CT Myelography following Lateral Decubitus Digital Subtraction Myelography with Negative Findings

S J Huls  1 , D P Shlapak  2 , D K Kim  2 , S Leng  2 , C M Carr  2
Affiliations

Utility of Dual-Energy CT to Improve Diagnosis of CSF Leaks on CT Myelography following Lateral Decubitus Digital Subtraction Myelography with Negative Findings

S J Huls et al. AJNR Am J Neuroradiol. 2022 Oct.

Abstract

CSF leaks, including CSF-venous fistulas, which cause spontaneous intracranial hypotension, remain difficult to diagnose, even on digital subtraction myelography and CT myelography. Dual-energy CT technology has been used to improve diagnostic utility within multiple organ systems. The capability of dual-energy CT to create virtual monoenergetic images can be leveraged to increase conspicuity of contrast in CSF-venous fistulas and direct epidural CSF leakage to improve the diagnostic utility of CT myelography. Six cases (in 5 patients) are shown in which virtual monoenergetic images demonstrate a leak location that was either occult or poorly visible on high- or low-kilovolt series. This clinical report describes the novel application of dual-energy CT for the detection of subtle CSF leaks including CSF-venous fistulas.

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Figures

FIG 1.
FIG 1.
A, 50-keV VMI. B, 100 kV. C, 140 kV. Case 1: Left-side-down CTM with linear contrast at the left T12–L1 neural foramen, thought to reflect a CVF (arrows). Contrast is also noted in the renal collecting system. ROI Hounsfield units: A, 50-keV VMI Hounsfield unit maximum (max): 283 HU; mean, 76 HU. B, 100 -kV Hounsfield unit max: 147 HU; mean, 68 HU. C, 140-kV Hounsfield unit max: 116 HU; mean, 46 HU. D, 50-keV VMI. E, 100 kV. F, 140 kV. Case 1: Right-side-down CTM with paraspinal contrast at the level of T11–12, representing a second CVF (arrows). ROI Hounsfield units: D, 50-keV VMI Hounsfield unit max: 981 HU; mean, 693 HU. E, 100-kV Hounsfield unit max: 542 HU; mean, 369 HU. F, 140-kV Hounsfield unit max: 233 HU; mean, 107 HU.
FIG 2.
FIG 2.
A, 50-keV VMI. B, 100 kV. C, 140 kV. Case 2: Left-side-down CTM with a suspected distal nerve root sleeve tear at the left L2–3 (arrows). The patient also had contrast in the renal collecting system (not shown). ROI Hounsfield units: A, 50-keV VMI Hounsfield unit maximum (max): 806 HU; mean, 271 HU. B, 100-kV Hounsfield unit max: 435 HU; mean, 133 HU. C, 140-kV Hounsfield unit max: 210 HU; mean, 68 HU.
FIG 3.
FIG 3.
A, 50 -keV VMI. B, 100 kV. C, 150 kV. Case 3: Right-side-down CTM with linear contrast at the right L2–3 neuroforamen (arrows), extending into the paraspinal soft tissues, thought to reflect a vessel associated with contrast leakage at a higher right-T10 distal nerve root sleeve tear (not shown). ROI Hounsfield units: A, 50-keV VMI Hounsfield unit maximum (max): 485 HU; mean, 118 HU. B, 100-kV Hounsfield unit max: 271 HU; mean, 51 HU. C, 150-kV Hounsfield unit max: 151 HU; mean, 16 HU.
FIG 4.
FIG 4.
A, 50-keV VMI. B, 100 kV. C, 140 kV. Case 4: Right-side-down CTM with a small focus of extradural contrast at the right aspect of the thecal sac at T7–8 (arrows). ROI Hounsfield units: A, 50-keV VMI Hounsfield unit maximum (max): 441 HU; mean, 275 HU). B, 100-kV Hounsfield unit max: 277 HU; mean, 165 HU. C, 140-kV Hounsfield unit max: 163 HU; mean, 102 HU.
FIG 5.
FIG 5.
A, 50-keV VMI. B, 100 kV. C, 140 kV. Case 5: CTM right-side-down at the level of T11–12 shows linear focus most consistent with a CSF venous fistula (arrows). ROI Hounsfield units: A, 50-keV Hounsfield unit maximum (max): 436 HU; mean, 154 HU. B, 100-kV Hounsfield unit max: 251 HU; mean, 88 HU. C, 140-kV Hounsfield unit max: 125 HU; mean, 33 HU.
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Comment in

  • Myelographic Timing Matters.
    Mamlouk MD, Shen PY. Mamlouk MD, et al. AJNR Am J Neuroradiol. 2023 Mar;44(3):E16. doi: 10.3174/ajnr.A7726. Epub 2023 Feb 23. AJNR Am J Neuroradiol. 2023. PMID: 36822824 Free PMC article. No abstract available.

References

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