What Imaging Method Is Best in Primary Hyperparathyroidism?

When it comes to identifying primary hyperparathyroidism (pHPT), choline positron emission tomography and computed tomography (PET-CT) may be the way to go.

In a meta-analysis of 119 comparative studies, choline PET-CT had the highest sensitivity for localization of primary hyperparathyroidism, Seong-Jang Kim, MD, PhD, of Pusan National University Yangsan Hospital in Korea, and colleagues reported in JAMA Otolaryngology-Head & Neck Surgery.

When compared with other imagining techniques including technetium (Tc) 99m sestamibi (MIBI) single-photon emission computed tomography (SPECT), choline PET-CT had significantly higher sensitively in both a patient-based analysis (OR 5.22, 95% credible interval [CrI] 2.36-11.80) and a lesion-based analysis (OR 17.70, 95% CrI 5.79-60.10).

The researchers also classified all imaging types into eight representative imaging categories. Among these, choline PET-CT had the highest surface under the cumulative ranking curve (SUCRA) value in both patient-based and lesion-based analyses.

Trailing behind choline PET-CT, CT imaging alone had the second highest SUCRA value in patient-based analyses, followed by carbon 11-labeled methionine (MET) PET-CT, MIBI planar, MIBI single-photon emission, MRI, dual tracer, and ultrasonography (US).

"The results of this [network meta-analysis] clearly showed that choline PET-CT, either FCH [fluorocholine] or CCH [carbon 11-labeled choline], should be the imaging method of choice for localization of pHPT in both patient-based and lesion-based analyses," Kim's group suggested.

"Among the various imaging methods, traditionally, neck US and parathyroid scintigraphy (either with SPECT or SPECT-CT) using the dual tracer subtraction technique or dual phase of MIBI have been well established for preoperative localization of pHPT, although there was no clear consensus on the optimal imaging approach," the researchers wrote.

For the study, they performed a systematic review of the PubMed, Embase, and Cochrane Library databases to find 119 direct comparative studies that included at least two imaging modalities of primary hyperparathyroidism. These studies included 48 that were prospective analyses, and 37 of which were performed after 2010. Data on 8,495 patients were included in the meta-analysis.

The group further divided the preoperative imaging techniques into eight main categories:

• Choline PET-CT, including FCH PET-CT, FCH PET-MRI, and CCH PET-CT

• MET PET-CT

• MIBI SPECT, including MIBI SPECT-CT, MIBI pinhole SPECT, MIBI SPECT-contrast-enhanced CT, Tc 99m tetrofosmin (TF) SPECT, and TF SPECT-CT

• MIBI planar, including MIBI pinhole and TF planar

• Dual tracer, including MIBI-Tc subtraction, MIBI-iodine 123 subtraction, TF-Tc subtraction, and thallium 201-Tc subtraction with planar, pinhole, SPECT, or SPECT-CT

• US including contrast-enhanced US, high-resolution US with color Doppler, 3-D US, endoscopic US, and surgeon-performed US

• CT, including 4D-CT and dual-energy CT

• MRI including 3T-MRI and dynamic MR angiography

The researchers called surgical resection of abnormal parathyroid glands through neck exploration "the mainstay for curative treatment" for primary hyperparathyroidism, and explained that proper image-guided exploration is key for performing minimally invasive parathyroidectomies.

Choosing the best technique can improve clinical outcomes, including reducing operation times, length of hospital stay, costs, and bolstering patient satisfaction, the team said.

Writing in an accompanying commentary, Martin Almquist, MD, PhD, of Skåne University Hospital in Lund, Sweden, noted that it can be difficult to find diseased glands in patients with primary hyperparathyroidism and that "even high-volume, experienced surgeons are sometimes unable to cure their patients."

A major strength of the study was that it incorporated all existing available interventions -- something that is rare, he said.

"The present study indicates that FCH PET/CT has promise to be the imaging modality that parathyroid surgeons have longed for," Almquist stated, adding, however, that this still needs to be confirmed with a randomized clinical trial comparing this imaging technique with standard imaging.

"Currently, more than one imaging study is often needed to provide accurate localization for pHPT. The present study indicates that there is great potential for FCH PET/CT to replace all other imaging modalities as a one-stop parathyroid imaging procedure," he concluded.

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