Clinical UM Guideline


Subject: SPECT/CT Fusion Imaging
Guideline #: CG-MED-77 Publish Date:    09/20/2018
Status: New Last Review Date:    07/26/2018


This document addresses the medical imaging technique in which the results obtained from a single photon emission computed tomography (SPECT) scan are merged with those obtained from a computed tomography (CT) scan (also known as hybrid imaging). This fusion may occur by the combining of images from two separate devices, or by the use of specialized equipment designed to perform both SPECT scanning and CT scanning simultaneously.

Note: Please see the following related document for additional information:

Clinical Indications

Medically Necessary:

The use of SPECT/CT fusion imaging is considered medically necessary in the evaluation of parathyroid glands in individuals with hyperparathyroidism when used for anatomic localization prior to parathyroid surgery.

Not Medically Necessary:

The use of SPECT/CT fusion imaging is considered not medically necessary for all other indications.


The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

Parathyroid Imaging:




Parathyroid planar imaging (including subtraction, when performed); with tomographic (SPECT), and concurrently acquired computed tomography (CT) for anatomical localization



ICD-10 Diagnosis



Benign neoplasm of parathyroid gland


Primary hyperparathyroidism


Secondary hyperparathyroidism, not elsewhere classified


Other hyperparathyroidism


Hyperparathyroidism, unspecified

All other SPECT/CT Fusion Imaging:
Note: imaging other than parathyroid is considered not medically necessary for all indications




Unlisted miscellaneous procedure, diagnostic nuclear medicine [specified as SPECT/CT fusion scan other than parathyroid]



ICD-10 Diagnosis



All diagnoses

Discussion/General Information

SPECT/CT fusion refers to the imaging technique that combines the functional information from SPECT with the anatomical information from CT into one set of images. The SPECT and CT images are either “fused” by a software package that superimposes two digital images together or are processed simultaneously by combined SPECT/CT scanners. In either case, SPECT/CT fusion has been purported to allow for more accurate diagnosis and thus improved outcomes and treatment.

Some SPECT procedures utilize whole body scanning (such as bone scans), SPECT studies typically focus on the function of specific organs, such as the thyroid, heart, lungs, gallbladder, liver and kidneys. SPECT agents (radiopharmaceuticals) incorporate antibody and peptide formulations that can be targeted to specific tissue receptors, allowing one to discriminate healthy from diseased tissue. SPECT agents can also be monitored for tissue changes over time, allowing physicians to narrow down the characteristics of a specific disease process. Because SPECT tracers have very specific characteristics, more than one agent, each emitting a particular energy level, can be injected to track related processes simultaneously. The goal is to be able to pinpoint both the disease process and its ongoing response to treatments. However, because there are fewer landmarks using SPECT, the more specific the targeting agent is, the more difficult it is to interpret its anatomical position. This may make it difficult for physicians to accurately interpret certain SPECT images.

A CT scan is a painless, noninvasive diagnostic procedure that uses x-ray equipment to obtain cross-sectional images of the body. With the aid of a computer, each cross-sectional image of the body is added together to create a tomogram, (a 3-D image of the internal structures and organs in the body). CT scans are performed to analyze the internal structures of various parts of the body. For example, in the event of traumatic injuries, CT scans may be taken to identify blood clots or fractures. CT scans are also used to aid radiologists in performing procedures such as the biopsy of suspected cancers, the removal of internal body fluids for testing, and the draining of abscesses located deep within the body. With regards to cancer, CT scans are used to detect or confirm the presence of a tumor, its size, location, whether it has metastasized (spread) and to monitor the body’s response to treatment.

By fusing SPECT and CT scans into a single procedure, researchers hope to obtain the superior metabolic information provided by SPECT studies with the clear anatomical information gained from CT scans. Performing the two exams while the individual remains on the table increases the likelihood of good image registration.

Parathyroid Imaging
The parathyroid glands are four small glands in the neck which control the body’s calcium level. Keeping a proper balance of calcium is essential to the normal functioning of other organs in the body including the heart, kidneys, bones, and the nervous system. Due to the size and location of the parathyroid glands, localization is important preoperatively. In a 2007 study by Lavely and colleagues, 98 participants had a diagnosis of primary hyperparathyroidism and single adenoma. Each participant had planar imaging, SPECT scanning, and SPECT/CT fusion imaging and comparisons were made to compare the accuracy of parathyroid SPECT/CT imaging to SPECT and planar imaging for localization of parathyroid adenomas. The overall sensitivity for localization for all modalities was 60%, specificity was 99%, positive predictive value (PPV) was 80%, negative predictive value (NPV) was 97%, and area under the curve (AUC) was 80%. When SPECT/CT was compared to planar imaging, the single-phase SPECT/CT was not significantly superior to dual-phase imaging for sensitivity, AUC or PPV of localization. The dual-phase SPECT/CT did have a higher sensitivity, AUC and PPV than the dual-phase planar imaging. When SPECT/CT was compared to SPECT scan, the dual-phase SPECT/CT was superior to dual-phase SPECT sensitivity and AUC for localization. The most superior method found was early SPECT/CT in combination with any delayed imaging when compared to a single- or dual-phase planar or SPECT scan for localization of parathyroid adenoma.

A study by Prommegger and colleagues (2009) evaluated 116 participants with primary hyperparathyroidism who had a SPECT scan and CT scan compared to SPECT/CT scan to determine whether the SPECT/CT fusion scan was superior in detecting abnormal parathyroid glands. The CT scan alone predicted the position of the abnormal gland in 75 participants, the SPECT scan alone predicted the position in 64 participants and the SPECT/CT fusion scan predicted the position of the abnormal gland in 102 participants. The sensitivity for CT scan was 70% and specificity was 94%. Sensitivity for SPECT scan was 59% with a specificity of 95%, SPECT/CT scan showed sensitivity of 80% with a specificity of 99%. A total of 62 participants underwent surgery. The authors concluded that the use of SPECT/CT fusion imaging had a higher sensitivity and specificity than CT or SPECT imaging alone when used for preoperative localization of parathyroid glands in those individuals with hyperparathyroidism.

In a 2015 meta-analysis by Wong and colleagues, the authors sought to determine the diagnostic utility of parathyroid scintigraphy with SPECT/CT fusion imaging for localization of parathyroid adenoma when compared to older planar and SPECT scans. A total of 24 articles were included in their analysis. Sensitivity of SPECT/CT was found to be 0.86 (confidence interval [CI], 0.81-0.90) compared to sensitivity of SPECT at 0.74 (CI, 0.66–0.82) and planar imaging at 0.70 (CI, 0.61–0.80). Using SPECT/CT imaging with parathyroid scintigraphy improves performance when compared to older planar and SPECT imaging.

Another meta-analysis by Treglia and colleagues (2016) reported on 23 articles in which participants with primary hyperparathyroidism had SPECT/CT fusion imaging prior to surgery. The pooled detection rate of SPECT/CT in preoperative planning of individuals with primary hyperparathyroidism was 88% (95% CI, 84% to 92%) on a per participant-based analysis and 88% (95% CI, 82% to 92%) on a per lesion-based analysis.

Based on expert opinion and guidance, SPECT/CT is found to be medically necessary for certain parathyroid indications, especially when compared with other imaging modalities. In a 2006 study by Sharma and colleagues, the authors compared the accuracy of four types of sestamibi-based scans for preoperative parathyroid localization. A total of 138 participants underwent planar imaging, 165 participants underwent SPECT scanning, 350 participants underwent SPECT with thyroid I-subtraction phase, and 180 participants underwent SPECT/CT imaging. False negative scans were noted in 38% of planar scans, 27% of SPECT scans, 4% of SPECT with thyroid I-subtraction phase, and 17% in SPECT/CT. The accuracy of each scan was determined based on intraoperative parathyroid pathology. When a single focus of uptake was noted on scan, a single adenoma was found at that location in 77% of planar imaging, 85% of SPECT imaging, 68% SPECT with thyroid I-subtraction, and 87% with SPECT/CT. A 2009 European Association of Nuclear Medicine parathyroid guideline notes that “Use of integrated SPECT/CT with a high spatial resolution, spiral CT used for anatomical localization, improves accuracy and reporter confidence in clinical practice.”

In a 2017 study by Sandqvist and colleagues, the authors reported on 249 participants who were biochemically diagnosed with primary hyperparathyroidism and received SPECT/CT imaging. A total of 200 participant records were reviewed following parathyroidectomy and compared to SPECT and CT images. The sensitivity for SPECT/CT was 83% with a specificity of 96% when compared to SPECT alone. SPECT alone sensitivity was 80% with a specificity of 93%. For small adenomas (less than 210 mg), SPECT/CT showed 67% which were graded with the highest confidence score, compared to 53% with SPECT alone.

Other Clinical Conditions
The use of SPECT/CT fusion has been studied for other clinical conditions. A 2011 guideline by the European Association of Nuclear Medicine (Flotats), reported on hybrid imaging for individuals with known or suspected coronary artery disease. In terms of cardiac imaging, the hybrid systems are not routinely used because of the difficulty in determining which individuals would benefit from the dual scanning and radiation exposure is reported as a concern.


Computed tomography (CT): An imaging technique that creates multiple cross-sectional images of the body by using special x-rays and computer enhancement to detect disease or abnormalities.

Single Photon Emission Computed Tomography (SPECT): An imaging technique that measures the concentration of chemicals injected into the body, and provides images of the chemical function of body parts of interest.


Peer Reviewed Publications:

  1. Lavely WC, Goetze S, Friedman KP, et al. Comparison of SPECT/CT, SPECT, and planar imaging with single- and dual-phase (99m)Tc-sestamibi parathyroid scintigraphy. J Nucl Med. 2007; 48(7):1084-1089.
  2. Liddy S, Worsley D, Torreggiani W, Feeney J. Preoperative imaging in primary hyperparathyroidism: literature review and recommendations. Can Assoc Radiol J. 2017; 68(1):47-55.
  3. Prommegger R, Wimmer G, Profanter C, et al. Virtual neck exploration: a new method for localizing abnormal parathyroid glands. Ann Surg. 2009; 250(5):761-765.
  4. Sandqvist P, Nilsson IL, Grybäck P, et al. SPECT/CT's advantage for preoperative localization of small parathyroid adenomas in primary hyperparathyroidism. Clin Nucl Med. 2017; 42(2):e109-e114.
  5. Shafiei B, Hoseinzadeh S, Fotouhi F, et al. Preoperative 99mTc-sestamibi scintigraphy in patients with primary hyperparathyroidism and concomitant nodular goiter: comparison of SPECT-CT, SPECT, and planar imaging. Nuc Med Commun. 2012; 33(10):1070-1076.
  6. Sharma J, Mazzaglia P, Milas M, et al. Radionuclide imaging for hyperparathyroidism (HPT): which is the best technetium-99m sestamibi modality? Surgery. 2006; 140(6):856-863.
  7. Treglia G, Sadeghi R, Schalin-Jäntti C, et al. Detection rate of 99m Tc-MIBI single photon emission computed tomography (SPECT)/CT in preoperative planning for patients with primary hyperparathyroidism: A meta-analysis. Head Neck. 2016; 38 Suppl 1:E2159-E2172.
  8. Wong KK, Fig LM, Gross MD, Dwamena BA. Parathyroid adenoma localization with 99mTc-sestamibi SPECT/CT: a meta-analysis. Nucl Med Commun. 2015; 36(4):363-375.

Government Agency, Medical Society, and Other Authoritative Publications:

  1. Centers for Medicare and Medicaid Services. National Coverage Determination: Computerized Tomography. NCD #220.1. Effective March 12, 2008. Accessed on June 28, 2018.
  2. Flotats A, Knuuti J, Gutberlet M, et al. Hybrid cardiac imaging: SPECT/CT and PET/CT. A joint position statement by the European Association of Nuclear Medicine (EANM), the European Society of Cardiac Radiology (ESCR) and the European Council of Nuclear Cardiology (ECNC). Eur J Nucl Med Mol Imaging. 2011; 38(1):201-212.
  3. Hindié E, Ugur O, Fuster D, et al. 2009 EANM parathyroid guidelines. Eur J Nucl Med Mol Imaging. 2009; 36(7):1201-1216.






Medical Policy & Technology Assessment Committee (MPTAC) review. Initial document development. Moved content of RAD.00042 SPECT/CT Fusion Imaging to new clinical utilization management guideline document with the same title.