Download surveillance imaging

Control# 1638
Poster# EP 130
RECCURENT MEDULLOBLASTOMA:
ROLE OF DIFFUSION WEIGHTED
IMAGING
Dr. Rakhee Gawande M.D and Dr. David Nascene M.D
Department of Radiology
DISCLOSURES
• NONE
INTRODUCTION
• Medulloblastoma is the most common malignant
CNS tumor of childhood
• Comprise 15-20% of CNS tumors of children
• 35-40% recurrence rate
• Surveillance imaging important for early detection,
prompt intervention and good outcome
• MRI of the brain and spine remain primary modality
for diagnosis of recurrence
• Since relapse is typically intra-cranial, surveillance
spine MRI has low yield
SURVEILLANCE IMAGING
• The reported rate of asymptomatic relapse is 1946%
• Multiple studies have shown that surveillance
imaging detected minority of recurrences with no
survival advantage
• Survival advantage limited due to our inability to
successfully treat recurrence.
• Current treatment regimen per the COG Phase II
screening trial (ACNS0821) include combination of
temozolomide, irinotecan, and bevacizumab
SURVEILLANCE IMAGING
• In the ACNS0821, recurrence is defined as tumor
measurable in two perpendicular dimensions on
MRI and histologic verification of malignancy at
original diagnosis, but not necessarily at the time of
recurrence.
• Recurrent disease should be differentiated from
treatment-related changes like radiation necrosis or
pseudoprogression
SITES OF RECCURENT DISEASE
• Relapse more common in young children
• Isolated local recurrence rare; usually
associated with meningeal dissemination
• Local recurrence not associated with
incomplete resection
• Risk for local recurrence influenced by
patient age and not by amount of residual
tumor
• Frontobasal region predominant site for
supratentorial meningeal recurrence
PURPOSE
To compare the rate of detection of recurrent
disease on diffusion weighted imaging (DWI)
with contrast enhanced imaging (CE-MRI)
MATERIAL AND METHODS
• Retrospective review of MRI of patients with
medulloblastoma
• Recurrence defined as an area of hyperintense
signal on DWI with iso-hypointense signal on ADC
(Apparent diffusion coefficient)
• And area of nodular enhancement on CE-MRI
RESULTS
• Database search from 2003 to 2013 revealed 45 patients
with medulloblastoma
• 12 patients (26%) suspected to have recurrent disease
• Mean age of patients at recurrence 17.1+/-14.4 yrs (range 4
to 47, median 11 yrs)
• Male: Female 8:4
• Mean time interval from diagnosis to recurrence is 36.3 +/32.5 months (range 6 to 113 months)
• Site of recurrence:
Cerebellum:7
Subependymal: 5
Basal cistern:1
RESULTS
COMPARISON OF DWI WITH CE-MRI:
• 9/12 patients with confirmed recurrence had
restricted diffusion signal (100%)
• Only 5/12 patients had contrast enhancement (55%)
• 2/12 patients with radiation necrosis had positive
contrast enhancement and no restricted diffusion
signal
SENSITIVITY SPECIFICITY
PPV
NPV
DWI
100%
75%
90%
100%
CE MRI
55.56%
33.33%
71.43%
20%
LOCAL RECURRENCE
DWI
ADC
38 yr old male with local recurrence 30
months after therapy along the
inferomedial right cerebellum. Note
restricted diffusion signal on an initial
scan without associated enhancement.
A close interval follow-up showed
enhancement in this region consistent
with biopsy proven recurrence
Post gad
3 month
Follow up
LOCAL RECURRENCE
6 mth
Follow
up
DWI
ADC
Post gad
8 yr old male with local recurrence in the right cerebellum
seen as an area of restricted diffusion signal with associated
enhancement. Note persistent disease on follow up scans
SUBEPENDYMAL RECURRENCE
DWI
ADC
Post gad
13 yr old female with subependymal recurrence 74 months
after therapy. Note enhancing nodular lesion in the midline
along the septum pellucidum with restricted diffusion signal
SUBEPENDYMAL RECCURENCE
DWI
ADC
Post gad
9 yr old female with subependymal recurrence in the
frontal horn of both lateral ventricles, 34 months after
therapy. Note absence of contrast enhancement with
clear detection of lesion on DWI
SUBEPENDYMAL RECCURENCE
DWI
Post gad
5 yr old male with subependymal recurrence seen 16 months
after therapy. Note that the lesion is easily identified on DWI
due to restricted diffusion signal. Lesion is not clearly
apparent on post contrast images.
SUBEPENDYMAL RECCURENCE
10 yr old male with
subependymal recurrence 56
months after therapy. The lesion
is easily identified in the anterior
body of the left lateral ventricle
on DWI and shows progressive
increase in size and restricted
diffusion signal over 1 yr period.
Note lack of contrast
enhancement and difficulty in
detection on the post-contrast
images. Lesion was missed on
several scans performed at an
outside facility.
DWI
ADC
Post gad
RADIATION NECROSIS
6 MONTH
FOLLOW
UP
DWI
ADC
Post gad
4 yr old female with patchy enhancement in the right cerebellum
9 months following treatment. Note absence of DWI signal
abnormality. Follow up imaging showed resolution of
enhancement without treatment, consistent with radiation
necrosis
CONCLUSION
• Restricted diffusion signal is commonly seen in
patients with recurrent medulloblastoma
• It can aid in the early detection of these lesions with
favorable outcome.
• Hence DWI images should be carefully scrutinized
in all patients and suspicious areas carefully
followed.
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