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LETTER TO EDITOR
Year : 2012  |  Volume : 60  |  Issue : 6  |  Page : 646--647

Role of FIESTA and SWAN sequences in diagnosis of intraventricular neurocysticercosis

Zafar Neyaz1, Sriram S Patwari1, Vimal K Paliwal2,  
1 Department of Radiodiagnosis, SGPGIMS, Lucknow, Uttar Pradesh, India
2 Department of Neurology,SGPGIMS, Lucknow, Uttar Pradesh, India

Correspondence Address:
Zafar Neyaz
Department of Radiodiagnosis, SGPGIMS, Lucknow, Uttar Pradesh
India




How to cite this article:
Neyaz Z, Patwari SS, Paliwal VK. Role of FIESTA and SWAN sequences in diagnosis of intraventricular neurocysticercosis.Neurol India 2012;60:646-647


How to cite this URL:
Neyaz Z, Patwari SS, Paliwal VK. Role of FIESTA and SWAN sequences in diagnosis of intraventricular neurocysticercosis. Neurol India [serial online] 2012 [cited 2021 May 7 ];60:646-647
Available from: https://www.neurologyindia.com/text.asp?2012/60/6/646/105205


Full Text

Sir,

Intraventricular neurocysticercosis is often missed on routine magnetic resonance imaging (MRI) of brain owing to similar signal intensity of cyst in cerebrospinal fluid (CSF) spaces and absence of contrast enhancement of cyst wall. Recently fast imaging employing steady state acquisition (FIESTA) and susceptibility weighted angiography (SWAN) sequences have been shown to better delineate the neurocysticercosis in the CSF spaces. We present two patients of intraventricular neurocysticercosis in whom cysts were diagnosed on FIESTA/SWAN sequences.

A 10-year-old girl presented with holocranial headache and vomiting of 2 months duration and normal neurological examination. Conventional MRI brain revealed dilated lateral and third ventricles with prominent and ballooned fourth ventricle. The initial impression was that of extraventricular obstructive hydrocephalus. A FIESTA sequence revealed a cystic lesion in fourth ventricle with cystic content showing slight reduced signal intensity as compared with CSF. An eccentric dot was also nicely delineated [Figure 1]. The cyst wall and eccentric scolex demonstrated by FIESTA that was missed by conventional MRI sequences helped in pinpointing the diagnosis of neurocysticercosis in this patient.{Figure 1}

A 35-year-old lady presented with seizures, diplopia, and vomiting of 15 days duration. Neurological examination revealed bilateral papilledema with normal vision and no other localizing signs. Conventional MRI brain showed hydrocephalous with a suspicious cyst in fourth ventricle extending into foramen of Luschka. The cyst was better delineated by SWAN and FIESTA sequences that clearly revealed the cyst wall as well as the eccentric scolex [Figure 2]. The patient underwent ventriculo-peritoneal shunt along with the medical management for cysticercosis. Follow-up MRI after 6 months revealed resolution of cyst and hydrocephalus.{Figure 2}

FIESTA also called 3D constructive interference in steady state (CISS) is a heavily T2-weighted (T2W) high-resolution sequence, which increases the conspicuity of lesions in cisterns, sulci, and intraventricular spaces. It is the best noninvasive sequence to show subarachnoid and intraventricular neurocysticercus. It produces greater conspicuity of cyst wall and scolex not otherwise evident on conventional FLAIR/T2 FSE sequences. [1] Hingwala et al. have urged routine use of these sequences in patients with suspected neurocysticercosis. [2] Dincer et al. diagnosed significant number of intraventricular obstructive hydrocephalus using 3D CISS that were misdiagnosed as extraventricular obstructive hydrocephalus on conventional sequences. [3] In our patients, the cyst and CSF were indistinguishable on T2W images, whereas on FIESTA sequence, cyst content showed slight lower signals making it stand-out in the background of CSF. SWAN or susceptibility-weighted imaging (SWI) is a fully velocity compensated high-resolution 3D gradient-echo sequence that uses magnitude and filtered-phase information, both separately and in combination with each other, to create new sources of contrast. SWI often offers complementary information valuable in the diagnosis of patients with neurocysticercosis. Verma et al. showed increased visibility of scolex when SWI was added to conventional sequences. [4] We conclude that FIESTA and SWI sequences may be added to conventional MRI sequence in evaluation of patients with unexplained hydrocephalus especially from endemic regions of neurocysticercosis.

References

1Govindappa SS, Narayanan JP, Krishnamoorthy VM, Shastry CH, Balasubramaniam A, Krishna SS. Improved detection of intraventricular cysticercal cysts with the use of three dimensional constructive interference in steady state MR sequences. AJNR Am J Neuroradiol 2000;21:679-84.
2Hingwala D, Chatterjee S, Kesavadas C, Thomas B, Kapilamoorthy TR. Applications of 3D CISS sequence for problem solving in neuroimaging. Indian J Radiol Imaging 2011;21:90-7.
3Dinçer A, Kohan S, Ozek MM. Is all "Communicating" hydrocephalus really communicating? Prospective study on the value of 3D-Constructive interference in steady state sequence at 3T. AJNR Am J Neuroradiol 2009;30:1898-906.
4Verma A, Awasthi R, Prasad KN, Soni N, Singh K, Paliwal VK, et al. Improved detection of parenchymal cysticercal lesions in neurocysticercosis with T2*-weighted angiography magnetic resonance imaging. Acad Radiol 2012;19:958-64.