IMAGING FINDINGS

The text below represents a broad overview. See individual articles below for details.

MRI

Pre-operatively, brainstem compression and infiltration/invasion by the tumor have been described [1, 2, 3]. Intra-operatively, bilateral diffusion abnormalities of the proximal dentato-thalamo-cortical pathway (also known as the proximal efferent cerebellar pathway) have been noted [13].  Post-operatively, edema of the middle and superior cerebellar peduncles (brachium pontis and conjunctivum) have repeatedly been documented [4, 5, 6, 3]. Later on, Hypertrophic olivary degeneration (HOD) [11, 12] and long-standing cerebellar atrophy have also been observed [3].

SPECT

Post-operatively, hypoperfusion of the cerebellum and cerebrum can be seen during the mute period [7, 8].

DTI

Post-operatively, bilateral functional disruption of white matter of proximal DTC-pathways has been described on the 1st day after surgery [4], and in one small study the superior cerebellar peduncles could not be discerned bilaterally; the time point for those post-operative scans, however, is not known [14]. Unilateral damage to white matter of proximal right DTC pathway as well as low volumes of distal right DTC pathway (left fronto-cerebellar fibers) have been observed over 2 years after surgery [9, 10].

Links to:

Definitions, Incidence, Symptoms, Anatomy, Pathophysiology, Risk factors, Prognosis, Treatment, Prevention

1. Di Rocco, Chieffo D, Frassanito P, Caldarelli M, Massimi L, Tamburrini G (2011) Heralding cerebellar mutism: evidence for pre-surgical language impairment as primary risk factor in posterior fossa surgery. Cerebellum 10: 551-562

2. McMillan HJ, Keene DL, Matzinger MA, Vassilyadi M, Nzau M, Ventureyra EC (2009) Brainstem compression: a predictor of postoperative cerebellar mutism. Childs Nerv Syst 25: 677-681

3. Wells EM, Khademian ZP, Walsh KS, Vezina G, Sposto R, Keating RF, Packer RJ (2010) Postoperative cerebellar mutism syndrome following treatment of medulloblastoma: neuroradiographic features and origin. J Neurosurg Pediatr 5: 329-334

4. Morris EB, Phillips NS, Laningham FH, Patay Z, Gajjar A, Wallace D, Boop F, Sanford R, Ness KK, Ogg RJ (2009) Proximal dentatothalamocortical tract involvement in posterior fossa syndrome. Brain 132: 3087-3095

5. Pollack IF, Polinko P, Albright AL, Towbin R, Fitz C (1995) Mutism and pseudobulbar symptoms after resection of posterior fossa tumors in children: incidence and pathophysiology. Neurosurgery 37: 885-893

6. van Dongen HR, Catsman-Berrevoets CE, Van Mourik M (1994) The syndrome of 'cerebellar' mutism and subsequent dysarthria. Neurology 44: 2040-2046

7. Catsman-Berrevoets CE, Aarsen FK (2010) The spectrum of neurobehavioural deficits in the Posterior Fossa Syndrome in children after cerebellar tumour surgery. Cortex 46: 933-946

8. De Smet HJ, Baillieux H, Wackenier P, De PM, Engelborghs S, Paquier PF, De Deyn PP, Marien P (2009) Long-term cognitive deficits following posterior fossa tumor resection: a neuropsychological and functional neuroimaging follow-up study. Neuropsychology 23: 694-704

9. Law N, Greenberg M, Bouffet E, Taylor MD, Laughlin S, Strother D, Fryer C, McConnell D, Hukin J, Kaise C, Wang F, Mabbott DJ (2012) Clinical and neuroanatomical predictors of cerebellar mutism syndrome. Neuro Oncol 14: 1294-1303

10. Soelva V, Hernaiz DP, Abbushi A, Rueckriegel S, Bruhn H, Eisner W, Thomale UW (2013) Fronto-cerebellar fiber tractography in pediatric patients following posterior fossa tumor surgery. Childs Nerv Syst 29: 597-607

11. Patay Z, Enterkin J, Harreld JH, Yuan Y, Löbel U, Rumboldt Z, Khan R, Boop F (2014) MR Imaging Evaluation of Inferior Olivary Nuclei: Comparison of Postoperative Subjects with and without Posterior Fossa Syndrome. A J Neruoradiol 35: 797-802

12. Spiteri M, Windridge D, Avula S, Kumar R, Lewis E (2015) Identifying quantitative imaging features of posterior fossa syndrome in longitudinal MRI. Journal of Medical Imaging 2(4): 044502

13. Avula S, Kumar R, Pizer B, Pettorini B, Abernethy L, Garlick D, Mallucci C (2015) Diffusion abnormalities on intraoperative magnetic resonance imaging as an early predictor for the risk of posterior fossa syndrome. Neuro-Oncology 17(4): 614-22

14. Ojemann JF, Partridge SC, Poliakov AV, Niazi TN, Shaw DW, Ishak GE, Lee A, Browd SR, Geyer JR, Ellenbogen RG (2013) Diffusion tensor imaging of the superior cerebellar peduncle identifies patients with posterior fossa syndrome. Child Nerv Syst 29: 2071-2077