MRI in the Staggging of Rectal Cancer - Imedex, LLC Slides/0941 Jhaveri - fina… · MRI in the...
Transcript of MRI in the Staggging of Rectal Cancer - Imedex, LLC Slides/0941 Jhaveri - fina… · MRI in the...
MRI in the Staging of Rectal Cancerg g
Kartik S Jhaveri, MDAbdominal ImagingAssistant Professor Faculty of MedicineAssistant Professor, Faculty of [email protected]
ObjectivesWhy MRI ?Normal MR AnatomyNormal MR AnatomyPreoperative StagingTTNM
• Post Treatment and Recurrence Evaluation• Conclusion
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Staging
ERUS
MRI PET-CTMRI
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Endorectal US(ERUS) has high accuracyaccuracy
So Why MRI…….?y
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Limitations of ERUS MRI
Small or Very large tumors Very High or Very Low MassSt ti CStenotic CancerMesorectal FasciaLN detection < MRILN detection < MRI
MRI is also performed sans ER device
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ERUS VS MRIT1 VS T2 ERUS
MST2 VS T3 MRI > ERUS
MT
T3 VS T4 MRI >ERUS RA
GN MRI >ERUS I
G
E
M CT/PET CT6
M CT/PET-CT
What About CT ?What About CT ?
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CT VS MRICT =Inferior Contrast Resolution
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NORMAL MRI ANATOMY
T2 AxialT2 Axial Inner High Signal -Mucosa/Submucosa
Middle Low Signal –
Muscularis Propria
Outer High Signal –
Mesorectal Fat
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T2 CORONAL
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T2 SAGITTAL
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MESORECTAL FASCIA
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ROLE OF HIGH RESOLUTION MRIPre-operative road map of tumor
T stage ( 2 , 3 OR 4)CRM (Circumferential resection margin)Di t f l / hi tDistance from anal verge/sphincter
• Define Prognostic groups• Define Prognostic groups
Deciding Preoperative therapyg p pyLocal Recurrence Risk
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ManagementT1 Transanal ExcisionT2T3
TMEPreop Chemorad + TMET3 Preop Chemorad TME
vs
T4TME + Postop Chemorad
• Preop Chemorad +ExenterationT4 Preop Chemorad Exenteration
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MRI AccuracyT Staging : 71-91 %N Staging : 43-85 %CRM 95 %CRM : 95 %Highest Accuracy and Consistency g y y
Beets-Tan RG et al. Lancet 2001Brown G et al. BJS 2003 & RSNA 2004 Nagtegaal I et al Am J Surg Path 2002
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Nagtegaal I et al. Am J Surg Path 2002
T Stageg
T1 s carcinoma in situT1 invades sub-mucosaT1 invades sub mucosaT2 invasion of circular/longitudinal layerslayersT3 invasion through muscularis T4 direct invasion of other organs orT4 direct invasion of other organs or visceral peritoneum
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T1
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T2
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T3
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T3Ci f i l R i M i CRMCircumferential Resection Margin =CRM
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CRM and MRIMRI : >6mm from CRM
P th l 2 N ti M iPathology >2mm Negative Margin
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Good and Bad T3
CRM >6 CRM 022
CRM >6mm CRM = 0 mm
T4
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T4
24Pre sacral infiltration
MRI PITFALLS IN T STAGET1 VS T2
T3 –DESMOPLASTIC REACTION-OVERSTAGINGOVERSTAGING
CRM Thin PatientsCRM -Thin Patients- Anterior wall tumor- Lower rectal tumor
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T1 OR T2
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T3 OVERSTAGING
Desmoplastic Reaction
RadioGraphics 2006; 26:701–714
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CRM
LOW AND ANTERIOR TUMOR28
LOW AND ANTERIOR TUMOR
N STAGEN0: No regional lymph node metastasis
N1: Metastases in1 to 3nearby lymph nodes
N2: Metastases in 4 or more nearby lymph nodesy y p
N3 : Distant LNRectum : External &CommonRectum : External &Common iliac and abdominal
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Criteria of nodal metastasis
Size : >8mm and round > 10mm in short axis and oval
Border : Spiculated or indistinctBorder : Spiculated or indistinct
Signal intensity
Enhancement pattern
Moderate accuracy, sensitivity and specificity !!!
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N STAGE
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Nanoparticle Enhanced MR –Nodal stagingNodal staging
USPIOUSPIO
NEJM . Harisinghani et al. 348 (25): 2491
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USPIO
BENIGN
MALIGNANT
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USPIO-enhanced MR Imaging for Nodal Staging in Patients with Primary Rectal Cancer.
Max J. Lahaye et al Radiology: 246: Number 3,March 2008
Short axis <10mm
Sensitivity 93%
Specificity 96%p y
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N-stage: PET/CT
Accuracy upto 80%Advantage of PET: Identification of sub-centimeter, metastatic nodes.
Disadvantage of PET: cannot detect small volume disease within nodes (microscopic metastases).
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Response Assessment To Ch R dChemoRads
MRIMRIDiffusion Weighted MRI (DWI)
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MRI
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MRI-CONTRAST
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Diffusion Weighted Imaging-DWIDWI is a recently introduced technique that depicts differences in molecular diffusion caused by thediffusion caused by the random and microscopic motion of molecules, which is known as Brownian motion
• Restricted Diffusion results in higher signal on DW image (EPI)-more typical of malignant tissueg
May have role for assessing or predicting treatmentor predicting treatment response by ADC calculation
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DWI-Rectal Cancer
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Recurrent Tumor Evaluation
Sagittal plane essential when assessing g p gsacral involvement
Recurrence often nodular in morphology
Post treatment fibrosis often co-exists
MRI or PET ?
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Recurrent tumorRecurrent tumor
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Recurrent tumorRecurrent tumor
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PET
P APR B i l B f hPost APR. Benign presacral mass: Bx of the mass was negative.
Malignant presacral tissue.45
g pAccuracy in high 90% for PET-CT
Intriguing Case
RECURRENCE ?
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CHRONIC SINUS TRACT OR RECURRENCERECURRENCE
2007
2008
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ConclusionEndorectal US for T1 VS T2MRI FOR Stage T3 and HigherMRI for CRM-Tumor distanceLower Accuracy for Nodal Staging? USPIO in future? USPIO in future
• PET-CT for Tumor recurrence in uncertain casesuncertain cases
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