Researchers from the U.S. and U.K. have developed an automated retrospective image reconstruction technique that helps to overcome poor image results from patient motion in cardiac PET scans. Their study was published online on 15 November in the Journal of Nuclear Medicine.
The so-called gross patient motion correction approach significantly increased maximum standardized uptake value (SUVmax) and tumor-to-background ratio (TBR) by as much as 30% and 40%, respectively, among patients undergoing thoracic sodium fluoride (NaF) PET scans. What's more, several lesions initially classified as being negative for NaF uptake were upgraded to NaF-avid after the technique was applied.
"We demonstrate a simple but effective automated data-driven patient motion compensation technique, which utilizes exclusively list-mode data, does not require any additional hardware during image acquisition, and can be applied retrospectively to data obtained with standard [PET] protocols," wrote lead author Martin Lyngby Lassen, PhD, from Cedars-Sinai Medical Center, Los Angeles, and colleagues from the University of Edinburgh in Scotland.
Patient movement can cause artifacts and blurred images, especially in cardiac studies. Thoracic PET imaging to evaluate calcification and coronary plaque is particularly susceptible to gross patient motion and cardiorespiratory motion. Both can reduce TBR and SUVmax, making it harder to detect abnormalities.
To correct for this issue, the researchers developed an image reconstruction and 3D coregistration process. First, they delineate the lesions and determine the reference PET images. Next, individual gross patient motion frames with focal coronary NaF uptake are coregistered in 3D to create motion-modified PET images.
Lassen and colleagues then tested the algorithm in 28 individuals (mean age, 68.5 ± 8.7 years) with confirmed multivessel coronary artery disease who underwent NaF-PET/CT (Biograph mCT, Siemens Healthineers) scans of their coronary arteries. The patients received 248 ± 10 MBq of NaF approximately one hour before 30-minute PET image acquisition and low-dose CT for attenuation correction.
The researchers then reviewed two different patient motion patterns: sudden repositioning, which is movement likely due to patient discomfort and defined in this study as motion of more than 0.5 mm within three seconds; and general repositioning, which is the result of normal muscle relaxation and includes motion of more than 0.3 mm over at least 15 seconds.
NaF-PET scans detected 35 lesions in 28 patient scans with no image modification. There were 110 patient repositionings during the scans, for an average of 3.9 movements per patient.
With the motion correction technique, SUVmax increased by 4.7% (p = 0.0001) and TBR increased by 8.4% (p < 0.0001) for NaF-avid lesions.
| Effect of PET motion correction on cardiac NaF-PET scans | |||
| No motion correction | After motion correction | Change | |
| SUVmax | 1.8 | 1.9 | 4.7% |
| Tumor-to-background ratio | 1.8 | 2.0 | 8.4% |
Gross patient motion correction also upgraded the diagnoses of three patients (11%) to NaF-avid lesions, from initial diagnoses of nonavid lesions.
Lassen and colleagues suggested their technique could be adapted to other PET imaging applications, given that the process begins with standard PET protocols and the same distribution of counts as in nonattenuation-corrected PET images.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&fit=crop&h=100&q=70&w=100)
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
