 Thank you Dr. Parkaswar, Dr. Malini, Medusa and the entire organizing team for taking all these efforts really commendable job. So my topic today is MR Deficography which is essentially the imaging for obstructive defecation syndrome. Now what is this obstructive defecation syndrome commonly referred to as ODS? It is a syndrome which is characterized by the urge to defecate but an impaired ability to expel that fecal bolus. So the symptoms typically include unsuccessful fecal evacuation attempts, excessive straining, pain, bleeding after defecation and a sense of incomplete fecal evacuation. The patients may also resort to digital rectal evacuation. So typically these patients keep going again and again to the loop. They are not able to evacuate completely. They keep getting the urge to defecate and the entire life starts revolving around the bathroom. So you know there's a lot of functional overlay that comes in and the quality of life is significantly impacted. So it is a very significant syndrome for the patient who is suffering from it and therefore the surgeons have taken a lot of interest in ODS and MR Deficography and we really want this to catch up. Now why is MR Deficography so important for these patients? That is because what MR Deficography does is it divides these patients into two distinct categories, two distinct subsets. One is that group of patients who show significant structural abnormalities on MR Deficogram. These abnormalities could be rectoseals, rectorectal intrususceptions, rectal prolapse, endosil, pelvic descents and so on so forth. These patients can then be offered specific surgical treatment for those specific structural abnormalities. The surgical approaches typically include the star surgery, S-T-A-R-R, that stands for Staple Transenal Reception of Rectum. The other surgery which is commonly done for these patients is the Laptroscopic Ventral Rectopexy, where the surgeon goes in laproscopically and they pull up the rectum and fix it. So basically that is the lap ventral rectopexy. So those are the typical surgeries that these patients undergo. Now the other group of patients are those who do not show significant abnormalities on MR Deficogram. So the MR Deficogram is essentially normal in these patients. These patients are not offered surgery. They are offered conservative treatment like diet modification, lifestyle modification and biofeedback therapy. Now very briefly, biofeedback therapy is typically done by the gastroenterologist or the electrophysiologist and they use a rectal balloon and an anal manometer and they sort of retrain the patients to contract and relax the pelvic soil muscles properly to ensure proper defecation. What happens is many of these patients they have pelvic dyscinergia wherein where certain muscles they are supposed to relax during defecation like the Tuber Actiles or the Excellence Finder, they inadvertently paradoxically contract these muscles during defecation causing the obstruction. So they are sort of retrained using these biofeedback methods so that their obstruction is resolved. See here it is very important for us to understand the surgeon's perspective. We all deal with surgeons day in and day out and when the ODS patients comes to a surgical openly, what is the surgeon interested in? He is interested in finding this subgroup of patients who have structured abnormalities for whom he can do surgeries. That is what he is interested in really. All these other patients, he is not really interested in those patients. Those patients he will just refer them to the other specialists, the gastroenterologist to you know take care of his conservative treatment diet modification and biofeedback because in this subgroup of patients who do not have structure abnormalities if he does a surgery the patient does not have an abnormality to start with so the surgery is not going to succeed. The symptoms are going to persist and the patient will keep coming back to his opiade and harassing him. So he doesn't want that. So therefore the surgeons are becoming very interested in MR Difficography because it helps them to pick up this specific subgroup of patients with specific structure abnormalities for which he can offer specific surgical treatment and have good results. When we started in 2009 this was the kind of equipment we were using you know a plastic bucket with a commode top and the x-ray in the horizontal position, horizontal beam position. We used to give the patient a rectal barium and also oral barium. This is how we used to position the patient and when the patient used to pass the stools he used to give a thumbs up sign and we used to shoot the x-ray and these are the kind of images we used to get. So you see a nice recto-seal, a big bulge of the anterior rectal wall that is a recto-seal and here you can see a recto-seal as well as the herniation of the small bowel looms down. So that is a recto-seal. It will be prudent at this stage to look at the basic anatomy of the pelvic floor. So this is the pubic symphysis that is the large pockageal articulation. So this line joining the inferior margin of the pubic symphysis to the large pockageal articulation that is the PC line. All the pelvic organ collapses and descents they are measured as tangent distances below this PC line. The other thing we look at is the inner rectal angle which is the angle formed by the posterior wall of the rectum and the long axis of the inner canal and that is another measurement that we do in these patients. So as things evolved and got better we started using MR difficulty. So now this is the kind of equipment we use or now a typical 1.5 Tesla magnet and this is how the patient is placed in the magnet during the difficulty. So when we initially were doing MR difficulty we were using a T1 weighted SPG as a sequence. So we used to mix a little bit of gadolinium in the ultrasound jelly and give it per rectum and we used to ask the patient to do the straining manoeuvres and the defecation manoeuvres. So these were the kind of images we used to get. You see you are getting good details of the posterior compartment of the rectum. You can see the rectocele here but the anterior and middle compartments are just a blob of hypo intense of tissue. You are not getting much information there but we radiologists are quite simple people. You know we were quite reasonably happy with these images and we thought the job was done. But the surgeons they are a difficult breed to please. I mean they always want more. Dilmange more is their motto. So they wanted more information for the middle compartment, more information of the anterior compartment and so we had to continue evolving and this is what we have done now. So now what we do is the face touch in a MR defecogram which is essentially a T2 weighted defecogram. So the advantages are obvious. You can see the other compartments also very well the anterior middle compartment even the small power loops. Also now we don't need to mix gadolinium with the ultrasound jelly. You can put the ultrasound jelly in the rectum and inherently it has a bright T2 signal. So now let's see the procedure. It's a very simple procedure to do all departments all routine MR departments should be able to do it. No patient preparation is required. There is per rectal installation of ultrasound jelly which is readily available in any radiology department. Now first it is important to do the routine T2 anatomic sequences of the pelvis because you don't want to miss some big pelvic mass which is causing obstruction to the rectum. So all other causes get ruled out by doing a pelvic sort of routine imaging and then we do the dynamic sagittal sequence in the spinae mode. Now when this sequence is running the patient has to do certain maneuvers. First he is addressed then the patient has to squeeze the pelvic floor inwards like something you do when you don't want to pass the stool. So at this stage he is trying to tighten the pelvic muscles inwards so that is the squeeze maneuver. After that the patient is asked to give short straining efforts and relax so strain and relax. So that basically shows you the excursion of the pelvic floor and lastly the patient is asked to give a sustained straining effort relax the external stintus and defecate. See the patient is wearing an adult diaper so there is no soiling of the table everything is well contained within the adult diaper. Also it is very important all these maneuvers you have to console the patient very well before taking him in the MR room. In the MR room there is a lot of noise he cannot very properly so before you take him in the MR room you have to console him well so that he does the maneuvers well because only then you will have a good diagnostic MR defecogram. So what happens during a normal defecography? So this is the position at rest that is the inner rectal angle that you can see that's the pubo rectal is sling there. When the patient does the squeeze maneuver he takes the pelvic floor in he contracts the pelvic muscles there is a mild elevation of the pelvic floor so the angle actually becomes acute the inner rectal angle becomes more acute. When the patient strains there is a normal physiologic descent of the pelvic floor as a result of which you see the inner rectal angle becomes wide and obtuse. What happens is because of this the rectum and the inner canal now become aligned in a straight line and the stage is set for defecation whereas the patient will relax the external center and the rectal jelly will pass out. This black line is the PC line all the distances descends are measured as perpendicular distances perpendicular tangents below the PC line this pink line is the edge line which indicates the size of the hiatus. So I believe in radiology the images should be so good that they should speak for themselves you know they should not need explanation. So what we will do is instead of having a lot of theory I will show you a series of cases of MR defecography whereas we will see how beautifully MR defecography depicts the various pathologies that are associated with ODS. So let's look at this case one now what happens is as the patient starts straining you see that bulge of the anterior rectal wall that is a rectocele. So it is a classical rectocele a classical anterior rectocele which is protruding anteriorly from the rectum and many times you may be able to see rectocele in one an asymptomatic patients but there are very specific radiological criteria for a clinically significant rectocele. Any rectocele which is more than two centimeters in length and which was retained contents at the end of defecation that is likely to be clinically significant. So this is a radiological criteria also rectocele are classified as mild moderate severe 0 to 2 centimeters length is mild 2 to 4 centimeters is moderate more than 4 centimeters is severe. This is how you measure the length of the rectocele from the expected anterior wall in the actual anterior wall you measure the length and that is the length of the rectocele. Also by looking at the images you can almost sort of correlate what the patients symptoms would be. See what happens is because there are retained contents in the rectocele the patient gets an incomplete sense of evacuation every time he goes and he feels like going back again and many times the patients are smart to evacuate the rectocele what they start doing is they start putting their hand and putting pressure on the perinium to empty the rectocele. The females may even put a finger in the vagina and push the posterior wall of the vagina so that it presses against the rectocele and empties the rectocele. Some patients may put a rectal finger into the rectum and try and evacuate the rectocele. So these are the typical histories you will get in these patients who have clinically significant rectocele. Now we look at the next case again the image itself should show the diagnosis you saw what happened the entire rectum telescoped into the anal canal so that is a recto anal into suception. So I will let it loop once more you see what happens there you see that is the telescoping of the rectum and this is a classical recto anal into suception and this sign that we get is known as the arrowhead configuration. So what symptoms do these patients have? These patients initially they do pass some stools and then the inter suception occurs and they get choked up. So typically the history will be that they do pass some stools initially but then they get blocked and that is typically what we see on the MR difficulty as well. Now this is a more severe form you see what happens here is as the patient duplicates there is an inter suception but then as it continues to strain the entire rectum prolapses out from the anal words along with the mesorectal fat. So this is a full thickness rectal prolapse I let it loop once more you see what happens the entire rectum now starts collapsing out along with the mesorectal fat and this is a full thickness rectal prolapse obviously these patients they will present with something coming out per rectum and many times they are themselves trained to sort of reposition it back into the anal canal. Sometimes it becomes irreducible when it becomes like an emergency. So these are the static images of that same patient. Now this again highlights the advantage of doing a fiesta MR difficult. You see what happens is there is some inter suception but more importantly there is a rectus seal and there is also bald and bladder descent they are coming way below the pubococcal line. You can see that on the static images you can see that's the PC line the bald is this tissue between the bladder and the rectum. So there is significant descents below the PC line. This patient then underwent a surgery a endoposture repair with sacrospinus fixation with a trans obturator tape and this is the post of MR difficult. You see now what's happening the bladder and bald they are staying put where they should be because they have been hooked up there so they are staying in position also the rectus seal and the inter suception which was seen earlier are no longer seen because that has been fixed you see there is no rectus seal. So this is showing significant imaging improvement and even clinically the patient had significant improvement. So this are the post of stills. Now this next case highlights a very important technical point for the radiologist when they are doing difficult graph. You see initially everything looks fine it's a little jerky difficult graph no but no doubt but everything is looking okay he's passing stools everything is fine but then later there is inter suception you see the telescoping of the rectum there. So this is important to highlight the fact that you have to run your difficult graph long enough because many pathologies they get elicited of the sustained straining during the latest stages of defecation. So if you run a short sequence you will feel everything is normal but it is the latest stages when there is sustained pressure that the pathologies come up. So it is important to run your sequence long enough at our center we run it for almost 150 to 180 seconds that I think is the bare minimum many times you may have to run it longer but shorter than that you are likely to miss pathologies which should come up in the later stages of defecation. This case shows a slightly different kind of pathology now what happens here is as the patient starts defecating you see there is a very prominent bulge of the bubo rectalis on the posterior wall and that keeps the inner rectal angle acute even during defecation remember during normal difficult I had said the inner rectal angle becomes obtuse but here the bubo rectalis is hyperactive hypercontracting even during defecation when it should relax and that is causing a very prominent bulge on the posterior wall and a very acute inner rectal angle. So these are patients who may be sent for biofeedback therapy to retrain their bubo rectalis to relax at the right time. Also one more therapy approach is they inject botulinum toxin into that tuber rectalis to cause a partial paralysis of that muscle and weaken that muscle. So these are the treatment approaches for these patients. This entity has several names you call it the tuber rectalis sling syndrome or the pelvic spastic perineum syndrome or the hyperactive tuber rectalis syndrome but essentially it's a tuber rectalis which is overactive and which is obstructing defecation. Now this case again highlights an important thing which the radiologist has to convey to the surgeon. So see what happens here. You see there is a mild interception a recto seal but more importantly can you see what's happening here. These are the small bubo loops which are coming deep down into the pouch of the glas and they are abetting the anterior wall of the rectum. So that is a entero seal I'll let it loop around once more. You see those loops there these loops. So on the static images you can see these loops are here they are abetting the anterior wall of the rectum. Now why is this so important. See one of the surgeries that I told you for these patients is the star surgery, staple transenal resection of rectum. So what they do in their surgery is that they put a circular stapler device per rectum and that device pulls in a circumferential band of the rectal ball and then when you fire the stapler that band of ball is resected and the two ends are sutured together. So that sort of shortens the rectum, takes care of the recto seal many times takes care of the rectorectal interception as well. Now in this patient if they put in the stapler when they will pull in the rectal wall it is possible that these small bubble loops may get also sucked into the stapler and if then the surgeon fires the stapler there will be a perforation of that small bubble and the patient will land up with a catastrophic abdominal peritonitis. So that is a disaster for the surgeon so this has to be avoided. So you have to make the surgeon aware of these small bubble loops. So what they do is then during surgery they give the patient a head loop so that the small bubble loops empty out from the pouch of the glass or they may even put in a laparoscope to ensure that all the small bubble loops are pulled out from that pouch of the glass. It is very important to prevent this catastrophic complication of small bubble perforation whilst firing the stapler during star surgery. Now this is a tricompartmental difficult. You see what we have done is we have also opacified the vaginal wall. So you have the bladder that's the wall the same ultrasound jelly in the vaginal wall and also in the rectum. So this is when surgeons they demand more they want to know details from the vaginal wall also. So you can do this. So this is a tricompartmental difficult. You can see the vaginal wall beautifully between the two and it helps to exactly assess the position of the vaginal loop. Another example of tricompartmental difficult. You see what's happening here. All the three compartments are showing significant descent below the pelvic floor. So all of them are going way below the pelvic floor. These are the static images and you can see the PC line and all three are descending. So this is known as a descending perenium syndrome. This is typically seen in older patients or in women who have multiple child breasts and they are very poor prognosis because what has happened here is that the entire pelvic muscle tone the pelvic floor tone is very poor and no amount of surgery can really fix that. So this is a typical multi-specialty approach to try and manage these patients but generally the prognosis is poor. The descents are graded as mild moderate severe 0 to 3 centimeter is mild 3 to 6 centimeter is moderate anything more than 6 centimeter is severe. One must remember that 0 to 3 centimeter that mild descent is physiological. It is normally seen during defecation and one does not have too much on that. So what are the pros of MR difficulty? Excellent soft tissue resolution, no ionizing radiation whatsoever, multi-tenor dynamic so you can keep repeating it before and after surgeries and it shows you all the three compartments of the pelvis. The cons are availability but now I am seeing more and more centers doing MR difficulty and that is a good sign. Also supine position was initially considered to be a disadvantage because it was considered to be non-cisilogic but that is no longer true because there was a very good article in radiographics where they compared supine versus erect MR difficulty and what they found was that any clinically significant pathology it will be picked up on the supine difficulty as well. The reason they postulated is the effort of training that is much more the pressure of straining is much more than gravity anyways. So if there is any clinically significant pathology the straining effort will elicit that pathology but the important caveat there is good straining effort. So you have to ensure that if the patient does not strain well during your study then it is slightly that your study may be non-diagnostic and suboptimal and you may miss pathology. So it is very important to console the patient well and ensure that he strains well during the defecogram. Now one trick that we have found useful is when many times when a patient is not able to strain in the routine supine position we allow him to flex the hips and the knee a little so the hip is flexed the knee is flexed and below the feet we give him a foot rest. So the what happens is the patient can then leverage his heels against the foot rest and by using that as a fulcrum as a leverage he can then defecate better he can then at least exert a better straining effort. So these are some tricks you learn along the way but ensuring a good straining effort is the key to getting a good diagnostic MR defecogram. This is our old data which we had published in the Indian Journal of Radiology in Saibhav 2015. Now why I am at defecograms just to conclude I would also like to mention one other test which is very useful for these patients with chronic constipation. This is a colonic transit study where we give around 20 let pellets to the patient in a capsule and then we take serial x's every 12 hours to monitor the progress. Usually the normal patient by 48 hours all the left pellets should be evacuated. If after 72 hours you keep following up and you see all the left pellets accumulating in the right side of the colon then that is the patient with a right colonic inertia or modality disorder. If all of them accumulate in the left colon that is the left colonic inertia or left colonic modality disorder and if all of them accumulate in the pelvis like this then that could be a pelvic inertia or that could be a obstructive defecation syndrome because he is not able to evacuate from that. Now importantly when you are doing this colonic transit study you must stop all the modality drugs that these patients are on for at least 7 days prior to doing the study because we want to analyze the native modality state of the patient's models. We don't want to see the effect of the drugs handling that. So you have to stop all the modality drugs for a week and then do the colonic transit study and many times this is done along with the MR difficulty of 32. I'd like to thank my colleagues Ritesh and Rukul who are my partners in kind for this and thanks a lot for your attention.