Ca Rectum Imaging

MRI in Carcinoma Rectum

1. CRC - Locoregional Imaging Dr Manoj K S DMRD MD RD DNB RD Consultant Radiologist KIMS

2. Multidisciplinary approach Rectal cancer staging has three crucial components: local staging, metastatic disease evaluation, and investigation of other bowel segments for synchronous tumors. Diagn Interv Radiol 2014; 20:390–398 Ümit Tapan, Mustafa Özbayrak, Servet Tatlı MRI in local staging of rectal cancer “ A multidisciplinary team consisting of a MRI radiologist, colorectal surgeon, medical and radiation oncologists, and gastrointestinal pathologist play a crucial role in overall care in patients with rectal cancer” AJR:199, July 2012 Vivek Gowdra Halappa1etaal

3. Rectal Anatomy The rectum varies in length from 10 to 15 cm from the upper end of the anal canal to the recto-sigmoid junction. Rectum divided into three parts: These three parts are defined from the anal verge (AV) as L ower rectum (0–5 cm), Middle rectum (5–10 cm), and Upper rectum (10–15 cm). The rectosigmoid junction is considered to be at the level of S3 by anatomists and at the level of sacral promontory by surgeons. The distal ring is regarded as the muscular anorectal ring by surgeons and as the dentate line by the anatomists.

4. imaging structural dynamic molecular tumor margins nodes relations

5. Local Staging Imaging Modalities Endorectal Ultrasound {ERUS} MRI [ HR MRI 1.5 T / 3 T / Endorectal coil ] MDCT PET CT PET MRI Circumferential resection margin (CRM) Extramural venous invasion (EMV), Sphincter complex status Extra mesorectal nodes Why MRI

6. MRI in Ca Rectum High-resolution T2-weighted imaging is the key sequence in the magnetic resonance (MR) imaging evaluation of primary rectal cancer. This sequence generally consists of thin-section (3-mm) axial images obtained orthogonal to the tumor plane, with an in-plane resolution of 0.5–0.8 mm MR imaging of primary rectal tumors can be used to assess the tumor in terms of (a) stage; (b) depth of invasion outside the muscularis propria; and (c) relationship to the mesorectal fascia, anal sphincter, and pelvic sidewall. The American Joint Committee on Cancer (tumor-node-metastasis [TNM]) guidelines have been used to develop MR imaging criteria for the staging of primary rectal tumors

7. Standardized Technique 3mm, 16cm-18cm FOV, 4-6 NSA, 256x256 matrix, TR >3,000, TE 80-100, ETL 16 In plane resolution 0.6mm x 0.6mm Brown G, Daniels IR, Richardson C et al Techniques and trouble-shooting in high spatial resolution thin slice MRI for rectal cancer. Br J Radiol 2005; 78:245-251 .

8. High-Quality MRI is a fundamental requirement to obtain accurate anatomical information of the tumoral relationships

9. MRI : Rectal anatomy The rectal wall is composed of three layers: Mucosa : A fine low-signal line Submucosa : High-signal layers Muscularis propria : Two low-signal layers (outer longitudinal and inner circular) at T2-weighted images The rectum is surrounded by mesorectal fat containing lymph nodes, superior hemorrhoidal vessels, and fibrous tissue, which are represented as high signal intensity surrounding the muscularis propria.

10. 3 Tesla MRI submucosa muscularis MRF mucosa

11. Mesorectal Fascia = Excisional Margin in TME = Circumferential Resection Margin(CRM) CRM is a term referring to the surgically dissected surface of the rectum corresponding to the non‑peritonealized part of the rectum. It is applicable to tumors below the peritoneal reflection of the rectum For upper rectal tumors, the CRM exists only posteriorly and in upper‑mid rectal tumors it is posterior and lateral

12. The MRF is only circumferential for rectal tumours below the anterior peritoneal reflection. The MRF does not apply to anterior, peritonealized surface of the anterior rectum above the anterior peritoneal reflection.

13. ERUS in Ca Rectum

14. T Stages of TNM Stage T1 tumors are confined to the submucosa; Stage T2 tumors invade the muscularis propria (arrows), which consists of a circular inner muscle layer and a longitudinal outer layer; Stage T3 tumors extend beyond the muscularis propria; Stage T4 tumors involve adjacent organs or the peritoneum.

15. MRI versus CT LOW 0-5cm, MID 5-10cm, UPPER 10-15cm

16. 3 Tesla MRI

17. Meta-analysis of 21 studies [from ESGAR] Magnetic resonance imaging for the clinical management of rectal cancer patients: recommendations from the 2012 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting

18. MRI Protocol

19. HR MRI Protocol Diagn Interv Radiol 2014; 20:390–398 Ümit Tapan, Mustafa Özbayrak, Servet Tatlı MRI in local staging of rectal cancer

20. HR MRI Protocol Imaging in rectal cancer with emphasis on local staging with MRI S upreeta Arya, Deepak Das, Reena Engineer1, Avanish Saklani2 Indian Journal of Radiology and Imaging / May 2015 / Vol 25 / Issue 2 Department of Radio‑Diagnosis, 1Radiation Oncology, and 2Surgical Oncology, Tata Memorial Centre, Mumbai, Maharashtra, India

21. MRI Rectum Technique Summary of Essentials Scan duration = quality 7mins average length of each sequence 4-6 NSA/NEX and T2- FSE / TSE /FRFSE 0.6mm x 0.6mm x 3mm = 1.1mm3 voxel Adequate coverage – 5cm above top of tumour Perpendicular to the rectal wall Low rectal cancer – parallel to anal canal Ensure discontinuous deposits are covered on high res Antispasmodics - Buscopan Saturation Bands Firm coil placement with secure abdominal compression

22. Rad-path correlation The Rectal doughnut

23. Rad-path correlation The Rectal doughnut T1 stage tumors extend upto the submucosa, while tumors extending into the muscularis propria without extension into perirectal tissues are T2 . It is not possible to reliably distinguish between T1 and T2 tumors on MRI (from Dr Gina Brown et al)

24. T2 Tumor T2 : invasion of circular/longitudinal layers

25. CRM status: A tumor–MRF distance >2 mm is CRM negative • A distance of <1 mm between the advancing tumor edge and MRF is indicative of a CRM‑positive status Also, CRM positivity could be due to tumor/ perirectal nodes / deposits / tumor stranding reaching <1 mm of the MRF When the tumor/node/deposit–MRF distance is between 1 and 2 mm,the CRM is regarded as “threatened”

26. Measuring depth of extramural spread Subclassification of T3 based on prognostic patterns T3 Spread into perirectal fat T3a Tumor extends <5 mm beyond the muscularis propria T3b Tumor extends 5‑10 mm beyond the muscularis propria T3c Tumor extends >10 mm beyond the muscularis propria

27. Nodal anatomy & MRI Correlation Two MRI criteria in perirectal nodes favor metastases: (a) heterogeneity of signal intensity on T2W sequences and (b) irregular margins Size criteria are unreliable as 30‑50% metastatic nodes in rectal cancers are <5 mm in size Afferent lymphatic Efferent lymphatics and vessels Medullary sinus Follicle Marginal sinus Capsule Morphologic criteria Size > 8mm/10mm short axis

28. Lymph node border and signal intensity –measuring size of nodes worsens results Node positive if either irregular border or mixed signal intensity was demonstrated, the sensitivity, specificity were high. Metastases were demonstrated in 51/56 nodes (91%, 95% CI 81% to 96%) with either an irregular border or a mixed intensity signal. Only 9/225 nodes (4%, CI 2.1% to 7.4%) with smooth borders and a uniform signal contained metastases. Size of node bears no relationship to malignant risk Dr Gina Brown et al

29. Extramural vascular invasion (EMVI) Extramural vascular invasion (EMVI) is a pathologic, microscopic feature that refers to invasion of large vessels deep to the muscularis propria and has consistently been shown to be an independent, negative prognostic factor in terms of survival. EMVI Negative • Pattern of tumour extension through muscularis propria is not nodular or no tumour extension in the vicinity of any vascular structure. • If stranding is demonstrated near extramural vessels, these vessels are of normal caliber with no definite tumour signal within EMVI Positive • Intermediate signal intensity within vessels in the vicinity of the tumour or obvious irregular vessel contour Smith NJ, Barbachano Y, Norman AR, Swift RI, Abulafi AM, Brown G. Prognostic significance of magnetic resonance imaging-detected extramural vascular invasion in rectal cancer. Br J Surg. Feb 2008;95(2):229-236

30. Extramural vascular invasion (EMVI) Discrete Serpiginous or Tubular Intermediate Signal Projections in Mesorectal fat MRI –Sens 62% - Spec 88%

31. ESGAR Recommendations Local invasion beyond the rectum A range for T-category should be reported (i.e., T2/early T3) if a definitive T-category cannot be accurately assessed Spiculation of the perirectal fat should be reported as a “T2/early T3 tumour Definite invasion: loss of intervening fat plane and corresponding T2 signal abnormality within the organ. Possible invasion: loss of intervening fat plane and no corresponding T2 signal abnormality within the organ. No invasion: preservation of the intervening fat plane

32. Ca Rectum - local invasion Invasion of adjacent organs Bladder, ureter, prostate, uterus/vagina, sacrum and/or internal and external iliac vessels. Invasion of the Levator Ani Puborectalis, pubococcygeus and/or ileococcygeus. Invasion of the Pelvic Side Wall Pelvic side wall muscles (obturator internus, piriformis and coccygeus) and/or internal iliac artery and vein. In general, tumours invading the pelvic side wall are considered unresectable

33. Ca Rectum - local invasion

34. Negative CRM (defined as > 1 mm) is associated with a significantly lower risk of local recurrence than a positive CRM (defined as < 1 mm) Quirke P, Durdey P, Dixon MF, Williams NS. Local recurrence of rectal adenocarcinoma due to inadequate surgical resection. Histopathological study of lateral tumour spread and surgical excision. Lancet. Nov 1 1986;2(8514):996-999 The minimum distance to the MRF should be reported for all T2 or higher stage tumours where the MRF can be adequately seen or can be reasonably estimated. • The minimum distance to the MRF refers to the shortest distance of the definitive tumour border to the MRF, where the definitive tumour border is the nodular or pushing border of the tumour and does not include spiculations or haziness of the perirectal fat. • If it is not possible to reasonably estimate the MRF, the minimum distance to the MRF should be reported as “unable to assess”. • The distance to the MRF should be reported as “not applicable” for tumours above the peritoneal reflection involving the peritonealized portion of the rectum (including T4a tumours). • For T4 tumours invading adjacent structures, the distance to the MRF should be reported as “0”.

35. Low rectal cancer Clinically, low rectal cancer is defined as rectal cancer located 0 to 5 cm from the anal verge. Low rectal cancers have been classified on MRI into two categories relative to the top border of puborectalis as suggested by the MERCURY group. These categories are: (i) Tumours in which the lower exent of the tumour is clearly above the top border of puborectalis and (ii) Tumours in which the lower extent of the tumour at or below the top border of puborectalis

36. Key Bioimaging markers for poor outcome at baseline and post CRT 1mm TME plane CRM involvement on MRI Depth of T extramural spread >5mm Presence of MRI detected contiguous or discontinuous venous invasion or vascular (non-nodal) tumour deposits MRI detected mucinous tumours Tumour spread into or beyond the intersphincteric plane MRI TRG status Dr Gina Brown : 2015 ,Best Practice for Rectal Cancer Staging

37. Features that have no adverse prognostic significance on MRI >1mm distance of tumour to TME CRM plane on MRI mrT2 versus mrT3a <1mm spread Depth of T extramural spread <5mm MRI detected lymph nodes MRI detected lymph nodes close to the mesorectal fascia

38. MR CRM prediction for low rectal cancers: TME plane safety MRI Low Rectal Stage 1 : tumour on MRI images appears confined to bowel wall (intact muscularis propria of the internal sphincter). MRI Low Rectal Stage 2 : tumour on MRI replaces the muscle coat but does not extend into the intersphincteric plane. Above sphincter it is confined to the mesorectum. MRI Low Rectal Stage 3 : invading into the intersphincteric plane or lying within 1mm of levator muscle above the level of the sphincter complex. MRI Low Rectal Stage 4 : invading the external anal sphincter and infiltrating/ extending beyond the levators +/- invading adjacent organ.

39. For tumors that are 5 cm or more above the AV, the sphincter is free • When the tumor is 0‑5 cm from the AV, sphincter invasion needs mention. Tumor reaching upto internal sphincter is T2 disease and can be offered an inter‑sphincteric resection when not reaching the inter‑sphincteric space and when at least 1 cm away from the AV Tumors reaching upto or <1 cm from AV require an APR. Tumor invasion into inter‑sphincteric space (T2 disease) or external sphincter (T3 disease) and into levator ani requires an extralevator APR after NACT‑RT to ensure negative resection margins Assessing Sphincter complex

40. Anatomic compartments beyond TME : the exenterative compartments from Dr Gina Brown

41. Assessment of Rectal Cancer: how good quality MR imaging can help surgeons Is it malignant or not? What is the depth of invasion? Are lymph nodes involved? is there EMVI? Is the proposed excision plane safe? Early Rectal Cancers EMR/ESD: TME Rectal Cancer Staging for primary TME vs preop CRT TME Low Rectal Cancer TME plane APE Beyond TME ELAPE Locally Advanced Rectal Cancer Beyond TME/Exenteration

42. Evidence base for MRI as a gold standard CRM involvement on MRI prognostic predictor for recurrence Depth of extramural spread >5mm risk factor for poor DFS Presence of MRI detected venous invasion – risk factor for local and distant recurrence and seen more frequently than path EMVI MRI detected mucinous tumours Tumour spread into or beyond the intersphincteric plane: risk of local recurrence MRI TRG status: independent prognostic predictor for overall survival and disease free survival and seen more frequently than the pathologic gold standard of pCR

43. MRI findings that justify preoperative chemo‑radiation CRM +ve or threatened T3b tumors with >5 mm spread into perirectal fat Sphincter complex involved Extramesorectal nodes (MRI used to re‑plan RT field) T2 and T3 disease with bulky mesorectal nodes Adjacent organ invasion (these are restaged after NACT‑RT to consider pelvic exenteration surgery) Invasion of the anterior peritoneal reflection in upper rectal cancers

44. Pre & Post CTRT Post‑treatment stage is indicated by the prefix “y.” Accuracy of MRI for predicting yT stage is 50% and for CRM at restaging is 66%,

45. Pre & Post NACTRT

46. Restaging after CCRT/NACT-RT “ Post-CCRT MR imaging has low accuracy in predicting the pathologic stage, with the major component of error being overstaging of pathologic stage T1 and T2 tumors ; the overstaging is due to the limited capability of MR imaging to allow differentiation between viable tumor, residual fibrotic nontumor tissue, and desmoplastic reaction. Understaging of irradiated rectal cancer can affect treatment planning, including the surgical strategy, and thus affect the tumor recurrence rate and patients’ prognoses “

47. Overstaging due to markedly hypointense tissue infiltration at the mesorectal fascia in a 65-year-old man with rectal cancer. (a, b) Axial T2-weighted images obtained before CCRT ( a obtained at a lower level than b ) show a hypointense mass in the rectum with involvement of the mesorectal fascia (arrow). (c, d) On corresponding axial T2-weighted images obtained after CCRT, the mass is markedly shrunken with low-signal-intensity tissue infiltration at the mesorectal fascia (arrow). At surgery, there was no tumor invasion of the mesorectal fascia.

48. CRC CE CT

49. Multi detector computed tomography (MDCT) scanning protocol 120 kV, 200-250 mA, tube rotation time of 0.5 s per rotation (pitch 6); 16×0.75mm collimation, table feed of 22.5mm per rotation and section thickness of 10 mm. Prior to scanning, 40 ml of ionic contrast (Diatrizoate Sodium) diluted in 2 litres of water -to drink over a period of 2.5 hours. - 100ml of contrast medium (Iohexol 300 mg/ml) intravenously at a rate of 3 ml/s.using power injector CT performed in the portal-venous phase with a 70 second delay between the start of contrast material administration and the start of helical scanning. The 10 mm-thick transverse CT images reconstructed at 2.5 mm intervals for interpretation of MDCT data

50. The upper node ( black arrow ) depicts a typical metastatic node: the node shows no contrast enhancement and remains hypo-intense except for an enhancing rim. The lower node ( white arrow ) shows the typical features of a benign node: the node shows a hyper-intense signal, comparable to that of enhancing vessels ( V ) and appears to have a relief. B The metastatic node ( black arrow ) shows no apparent contrast enhancement Gadofosveset-enhanced 3D T1-weighted gradient-echo images

51. MR Volumetry Although MR volumetry sometimes results in overestimation of the volume of the remaining tumor after CCRT, there is good correlation of the tumor volume and reduction after CCRT between MR imaging and histopathologic analysis. However, MR volumetric evaluation cannot demonstrate any differences between patients with complete histologic regression and those with residual disease Restaging of Rectal Cancer with MR Imaging after Concurrent Chemotherapy and Radiation Therapy Dae Jung Kim, MD • Joo Hee Kim, MD • Joon Seok Lim, MD • Jeong-Sik Yu, MD Jae-Joon Chung, MD • Myeong-Jin Kim, MD • Ki Whang Kim, MD RadioGraphics 2010; 30:503–516

52. PET CT

53. Primary Rectal Cancer Primary Colon Cancer Staging – MRI abdomen + pelvis with contrast (to assess liver also) If no outside/previous good quality imaging If NACT/RT not indicated- Xray Chest If NACT/RT indicated or high risk tumors- CT Chest with Pre NACT/RT Planning CT If good quality outside imaging is available- CT/MRI- the same will be considered sufficient Post NACT/RT assessment- At the end of 5 weeks Clinical assessment- p/r MRI Pelvis Plain + USG abdomen CECT abdomen + pelvis For low risk patients CXR For high risk patients (High CEA/ bulky tumor/nodal disease) CT Chest For patients with resectable metastases/planned for morbid surgery (eg pelvic exenteration) PET CT to rule out disseminated disease

54. 3 Tesla MRI High resolution DWI (multiple B value ,IVIM) DCE (T1 PERFUSION) Fusion imaging Subtraction Parametric maps Texture/Histogram

55. PET-MR Multiparameteric PET-MR Assessment of Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer: PET, MR, PET-MR and Tumor Texture Analysis: A Pilot Study Full-Text HTML XML Download as PDF  (Size:1013KB) PP. 49-60 DOI: 10.4236/ami.2015.53005    2,536 Downloads   3,099 Views   Citations Author(s)     Leave a comment Ur Metser 1* , Kartik S. Jhaveri 1 , Grainne Murphy 1 , Jaydeep Halankar 1 , Douglas Hussey 1 , Paul Dufort 1 , Erin Kennedy 2

56. Radiogenomics

57. Thank You All