J Korean Soc Radiol.  2010 Jul;63(1):1-7. 10.3348/jksr.2010.63.1.1.

Cerebral Sparganosis: The Differential Features between Live and Degenerated Worms on CT and MR Images

• Kim MS
• Yu IK
• Chang KH
• Han MH
• Kim MS
• Lee BH
• Lee YH

• KMID: 2208878
• DOI: http://doi.org/10.3348/jksr.2010.63.1.1

Abstract

PURPOSE
The purpose of this study is to describe the characteristic features of cerebral sparganosis with live worm on CT and MRI as compared with the characteristic CT and MRI features of degenerated cerebral worms.
MATERIALS AND METHODS
Twelve patients with surgically-proven live worms (the live group) and 13 patients with degenerated worms (the degenerated group) were included in this study. We retrospectively reviewed the CT scans of all the patients and the MR images of 19 patients.
RESULTS
The live group showed highly attenuated lesion (50-70 HUs for the CT number) on precontrast CT with surrounding enhancement extending to the cortical surface, a mass effect and change of the location and shape of the enhancing lesion on the follow-up images, whereas the degenerated group showed punctate calcification (more than 130 HUs) with surrounding enhancement and cerebromalacia in 77% of the subjects (p<.01). The highly attenuated lesion had an amorphous nodular or nodulotubular shape, and these lesions were slightly hyperintense on the T1-weighted MR images and hypointense on the T2-weighted MR images.
CONCLUSION
In patients with cerebral sparganosis, live worm infection is highly suggested if there is a focal amorphous hyperattenuated lesion on the precontrast CT with a surrounding mass effect, irregular nodulotubular enhancement extending to the pial surface and change of the enhancing lesion on the follow-up images.

MeSH Terms

Encephalomalacia
Follow-Up Studies
Helminths
Humans
Magnetic Resonance Imaging
Parasites
Retrospective Studies
Sparganosis

Figure

• 

  Fig. 1 A 29-year-old male patient with a live worm. A. On the precontrast CT, focal nodular highly attenuated lesion (arrow) is seen in the right anterior frontal cortex with surrounding low density. Note the mildly compressed ipsilateral frontal horn of the lateral ventricle. B. On the postcontrast CT, the ring-shaped densely enhancing lesion (arrow) is seen just around the highly attenuated lesion. C. On the postcontrast CT six month later, the previously enhancing lesion totally disappeared and cortical atrophy and ipsilateral ventricular dilatation remained (arrow). D. On the T2-weighted MR image (at the same time as for Fig. C), the irregular nodular-tubular low signal intensity lesion (black arrow) with surrounding high signal intensity is seen in the right high frontal cortex. E. On the T1-weighted MR image, this lesion (arrow) shows iso-signal intensity. F. On the postcontrast T1-weighted MR image, the irregular nodulotubular shaped enhancing lesion (arrow) is well visualized from the pial surface to the white matter in the right frontal lobe. G. On the postcontrast T1-weighted coronal MR image 2 month later, the shape of the enhancing lesion (arrow) is slightly changed. H. On the surgical field, a live spargana worm (arrow) was found at the site corresponding to the enhancing lesion on MR.

• 

  Fig. 2 A 52-year-old male patient with a degenerated worm. A. On precontrast CT, irregular punctate calcifications (arrows) are seen in the high frontoparietal cortex and subcortical white matter with no surrounding low density. B, C. On the follow-up MR 39 months later, localized cortical atrophy (white arrows) is seen with low signal intensity on the T1-weighted image (B) and high signal intensity on the T2-weighted image (C). Note the focal low signal intensity lesion in Fig C (black arrow), which seems to be the calcified lesion seen on CT. D. After gadolinium injection, the ring shaped focal enhancing lesion (arrow) is seen with surrounding atrophy.

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