Expert Responses: Cirrhotic Liver

B Value for DWI

What b value do you use for dwi?

Yeah, what b value for DWI, we do three separate sequences at varying B values.

And, frankly, I'm pretty stupid when it comes to the physics of mr.

So, I don't know that I could really tell you that with any reliability.

I find it hard to predict in advance which one is gonna work best.

So we do several in all of these cases.

Sorry, I know that's incomplete, but reflects my ignorance.

Cutoff for Regenerative Nodules

What was your cutoff for the regenerative nodule that looked like a case where, You had a regenerative nodule that looked like a dysplastic nodule?

And what was your cutoff for calling regenerative?

Yeah, there's no, there's probably very little in the way of published literature on this.

I would say if I see a lesion that's getting above two, two and a half centimeters in size, I'm starting to worry about that.

The great majority of simple cirrhotic regenerative nodules are less than two centimeters in size.

So once it gets bigger, I'm gonna apply greater scrutiny.

And now that would be in fact with Mr.

HCC Screening with DWI

Should HCC screening be done with only DWI? Wow.

I don't think so.

We employ that as one of the many sequences we do.

That sounds like somebody that's had experience or read an article about that.

I think DWI is a very valuable adjunct, but, I'm not aware that anybody is proposed with documented evidence that diffusion weighted imaging alone is sufficient.

So I would say no.

Follow-up Recommendations for IPMN

What are your recommendations for follow up of IPMN?

Oh, we're going backwards, diagnosed by CT for the first time.

Well, it depends. If it's a main branch, IPMN needs very close scrutiny.

It's probably gonna require surgery.

In fact, barring advanced stage or comorbidities, if it's a small side branch, IPMN, I would be content to follow it with imaging, up until the point, which will likely never come when it, the largest cystic component, is more than three or approaching, or more than three centimeters in diameter.

And I reiterate, so far, nobody has described a invasive carcinoma in any IPMN or for that matter, any spherical simple appearing cyst of any sort, of less than three centimeters in diameter.

So that's how I approach that.

Did I get the rest of that question?

And, several people asked me, well, come on.

We see these little sub centimeter lesions every day on ct.

Or mr do you mean to say, and does the a CR really mean to say that every one of those needs multiplanar CT with curved planar, reformation and Mr.

And so forth to characterize it?

No, I don't mean to say that at all.

Again, I think we need some common sense.

It really, really seems that side branch IP mns grow very slowly,

and if you have a little one centimeter simple appearing cystic lesion, I didn't even talk about the congenital cyst and so forth, which some of those are,

but most of these are probably gonna be side branch IPM ends.

And if that lesion is one centimeter in size and you've got a patient who's elderly or who has some other bad disease like emphysema or cirrhosis or cancer, it is extremely likely that that little lesion is never going to grow to the size of being clinically significant.

And so I will describe those lesions in the body of the report and say, likely of no little or no clinical significance, signs of cirrhosis, yes, here you go.

Signs of Cirrhosis

Signs of cirrhosis, maybe small, but not always.

Here's the signs you wanna rely on.

Widened fissures, deep gallbladder fossa.

I'm not much of a measurer, but here's one that's real easy to remember and works really well.

Take the bifurcation of the right portal vein, draw a line from that point to the edge of the caudate.

Draw a parallel line from that point on the same line to the right lobe of the liver.

The normal caudate lobe is never more than 60% of the width of the right lobe.

And in cirrhosis, the caudate is almost always equal to or greater in diameter than the right lobe.

And then you're gonna look for nodularity signs of portal hypertension to include splenomegaly, varice, and ascites.

That's how you diagnose cirrhosis.

Rules for Ignoring Fads in the Non-Cirrhotic Liver

Some rules for ignoring fads in the non-cirrhotic liver.

Let me put in a plug for my colleague Terry Desser, who has written a fabulous review article on THDs and Thad.

It's unfortunately published in kind of an obscure journal that most of us don't read seminars in CT ultrasound, Mr that's not meant to be a put down, but it just is gonna escape your thing.

So look up her name. Last name is Desser, D-E-S-S-E-R.

And so do a Google search for Desser and Thad, THAD, and you'll find this wonderful article that explains the pathophysiology, of thas and distinguishes among all the various, types.

So that's, I mean, she gives a beautiful hour long talk on that, and I've got my own talk on that.

Rules about THADs

Okay. What are some rules about thad's?

Anything that causes decreased portal venous flow or increased arterial flow will result in a Thad or a thd, which by definition is a zone of high hyper enhancement on arterial phase that equilibrates on portal venous or delayed phase.

So anything that causes portal venous thrombosis, could be a hypercoagulable state, could be a metastasis arriving at the liver, particularly via the GI tract, could be an AV fistula that, that little AV fistula that I caused with the biopsy had a Thad in the region of the left lobe because there was increased arterial, supply of contrast feeding the portal venous system there.

So it's probably too long to answer from the podium.

It's a great question.

It's a great thing to look into and read about.

And we've got actually, in my various books and so forth, I have chapters on THDs and thas and explain that as well.

Post-RFA Imaging

Briefly comment on post RFA imaging. Sure.

Interesting topic. Challenging.

And here's what I would tell you about that.

Expect for the first few weeks after RF ablation for the ablated lesion to have a thin rim of hyper enhancement.

That's okay. That's granulation tissue.

If it's nodular or thicker than a thin rim or increasing than its untreated tumor and needs an additional RF treatment.

Largely the same thing is appropriate for patients who have had taste trans arterial chemo embolization with regular chemotherapy or atrium 90, glass beads, same sort of thing.

We don't expect enhancement okay.

To have a little thin rim of granulation tissue.

Not okay to have nodular or thicker, enhancement.

Obviously not okay for the lesion to get bigger.