Clinical SPECT/CT—Time for a New Standard of Care

I haven't been able to attend the SNMMI (Society of Nuclear Medicine and Molecular Imaging) meeting in quite a while. It is unfortunately scheduled on the first week of June, and even if I can score the week off, I'm usually off on vacation with the family.

This year's meeting was in Vancouver, my most favorite city on the planet, so I'm doubly deprived. It's in St. Louis next year, and I'm going to try my best to be there.

One of the highlights of the SNM (I still can't get used to the new title) is, not coincidentally, the "Highlights" lecture at the end of the meeting. There are several different sections of this concluding talk, but I'm most intrigued by the General NM talk given by Alan H. Maurer, M.D., from Temple University School of Medicine, Philadelphia, Pennsylvania. I've stolen the title of his talk, "2013 SNMMI Highlights Lecture: General Clinical Nuclear Medicine: Clinical SPECT/CT—Time for a New Standard of Care" for this article.

Dr. Maurer starts off with a brief synopsis of the not-quite parallel development of the otherwise similar technologies, PET/CT and SPECT/CT. PET/CT appeared much more rapidly:

The timelines of the early development of SPECT and CT are roughly synchronous. The question, then, is why has the evolutionary progress been so much slower from SPECT to SPECT/CT (>40 years) than from PET to PET/CT (<20 years)? Among possible explanations are the lack of separate reimbursement for most SPECT/CT procedures, an already large installed base of standalone SPECT units, and the need for more studies documenting clinical cost effectiveness.

As usual, money talks. If reimbursement is the same for a scan from a $300K machine as that performed on a $1M machine, why buy the latter? The bean-counters won't grasp that the more expensive machine does a better job, or in modern ACA-tainted parlance, "Adds Value" to the scan. It costs more, and you won't be getting it anytime soon.

But Dr. Maurer just changed the rules of the game. 

My overall conclusion, and one that I will illustrate with examples from presentations at the 2013 SNMMI Annual Meeting, is that SPECT/CT is a new standard of care that we should be performing on a regular basis, just as we do with PET/CT. Multiple studies at this meeting showed not only increased sensitivity, specificity, and accuracy, but increased reader confidence, decreased interobserver variability, as well as a broad range of new applications with SPECT/CT.

And illustrate he does.  Here are just a few examples lifted from the article:

A Swiss study examined SPECT/CT vs. MRI in the evaluation of wrist pain:

Experienced and inexperienced readers looked at images from 32 patients (Fig. 1). Experienced readers’ results with SPECT/CT showed accuracy, specificity, and sensitivity of 77%, 90%, and 74%, respectively. The respective figures for MR imaging were 56%, 10%, and 65% and for planar bone scan were 44%, 70%, and 39%.

A group from Alberta, Canada brought back the old tried and true Gallium study, with rather amazing results:

“Bone/gallium SPECT-CT is equivalent to contrast-enhanced MRI in the diagnosis of infectious spondylodiscitis: a retrospective study”. The retrospective study included 34 patients with suspected spondylodiscitis. Bone/gallium SPECT/CT was found to have similar sensitivity, specificity, PPV, NPV, and accuracy (94%, 100%, 100%, 94%, and 97%, respectively) to MR (94%, 100%, 100%, 80%, and 95%, respectively) (Fig. 8). Although prospective research is needed, the authors concluded that these results suggest that bone/gallium SPECT/CT is equivalent to contrast-enhanced MR imaging in the diagnosis of infectious spondylodiscitis.

Take that, MRI!

I've been promising my clinicians an improvement in parathyroid scanning once the new SPECT/CT arrives:

A group from Sapporo, Japan, experienced in parathyroid imaging

. . . compared high-resolution ultrasound, 99mTc-sestamibi scans, and multidetector CT for presurgical evaluation of multigland disease in 25 patients (8 with primary and 17 secondary hyperparathyroidism) with 78 involved glands. Fused SPECT/CT yielded the highest sensitivity of all modalities as well as the highest PPV.

Clearly, the addition of CT to SPECT allows for far more precise localization and characterization of the scintigram. It is so intuitive, it almost goes without saying. 

Somewhat unfortunately, Dr. Maurer's conclusion backed off a tiny bit from his profound observation at the beginning of his talk:

As noted earlier, I believe that just as we have established PET/CT as a standard of care, we should now be moving toward SPECT/CT as our standard of care. The presentations at this year’s SNMMI meeting reinforce this belief. At the same time, we need more outcomes and effectiveness data before SPECT/CT will be properly reimbursed so it can achieve more widespread routine clinical use.

Yes, we should indeed be moving toward SPECT/CT as the standard of care. But in truth, we are there, and even a cursory look at a SPECT without CT shows just how critical it is to pair the two. I'll go with Dr. Maurer's original sentiment. SPECT/CT IS the new standard of care. I'll even go way, way out on a limb, which will make the bean-counters tear their hair out, and the equipment-makers jump for joy: There is no longer any reason to buy a conventional SPECT camera; EVERY NEW GAMMA CAMERA (perhaps with a few exceptions for narrow, dedicated applications) SHOULD BE A SPECT/CT device. Period. SPECT/CT is now the de facto standard of care, and it is sheer foolishness to buy 40-year-old technology in its stead. How many PET scanners (as opposed to PET/CT) are being sold today? Just about none. I hope to be able to make that claim for SPECT/CT within two to three years.

Due to various bureaucratic and CON snafus, I won't be getting MY SPECT/CT until early next year. Since we were delayed so long, we were able to upgrade to the latest and greatest Siemens Symbia Intevo SPECT/CT:

You will be hearing a LOT about this beauty from me once it's installed.

I plan to provide my patients the standard of care. You should, too.