Performance of ¹¹C-Pittsburgh Compound B PET Binding Potential Images in the Detection of Amyloid Deposits on Equivocal Static Images

Abstract

The goal of this study was to clarify whether binding potential (BP) images using 11 C-Pittsburgh compound B ( 11 C-PiB) and dynamic PET can reliably detect cortical amyloid deposits for patients whose 11 C-PiB PET static images are ambiguous and whether visual ratings are affected by white matter retention. Methods: Static and BP images were constructed for 85 consecutive patients with cognitive impairment after 11 C-PiB dynamic PET. Cortical uptake was visually assessed as positive, negative, or equivocal for both types of images. Quantitatively, the standardized uptake value ratio (SUVR) from the static image, the nondisplaceable BP from the dynamic image for mean gray matter uptake, and the ratio of gray matter uptake to white matter retention were compared among 11 C-PiB-positive, 11 C-PiB-equivocal, and 11 CPiB-negative groups. Results: Forty-three scans were visually assessed as 11 C-PiB-positive in both the static and the BP images. Ten scans were 11 C-PiB-equivocal in the static images. In 8 of them, the BP images were 11 C-PiB-positive, whereas the other 2 were 11 C-PiB-equivocal. Thirty-two scans were assessed as 11 CPiB-negative in the static images. In the BP images, 4 were 11 CPiB-positive and 2 were 11 C-PiB-equivocal. The mean gray matter uptake of 11 C-PiB in SUVR and nondisplaceable BP, respectively, showed statistically significant differences among the 11 C-PiBpositive, 11 C-PiB-equivocal, and 11 C-PiB-negative groups. The ratio of gray matter uptake to white matter retention was lower in the BP images than static images from the 11 C-PiB-negative and 11 C-PiBequivocal groups, whereas it was higher in the 11 C-PiB-positive group. Conclusion: 11 C-PiB PET BP images can clarify visual interpretation of clinical static 11 C-PiB-equivocal images by reducing the interference of nonspecific white matter retention. We conclude that 11 C-PiB-equivocal PET findings on static images reflect cortical amyloid deposits, which can be verified using BP images. Furthermore, quantitative assessments, such as SUVR and nondisplaceable BP, are of no use for correctly rating equivocal visual findings.

I-123 iomazenil single photon emission computed tomography for detecting loss of neuronal integrity in patients with traumatic brain injury

“…LPR corresponded to distribution volume ratio (DVR) of IMZ because delayed IMZ SPECT activity and distribution volume of IMZ SPECT had high linear correlation [11]. BP ND is equal to the DVR minus a value of 1, as described by Innis et al [13, 14]. We compared FMZ BP ND and (LPR-1) of delayed IMZ SPECT (Fig.…”

Quantitative Evaluation of 18F-Flutemetamol PET in Patients With Cognitive Impairment and Suspected Alzheimer's Disease: A Multicenter Study

“…Interrater disagreement was limited to cases in which it was difficult to judge whether or not one region showed increased accumulation, which is susceptible to interference by non-specific white matter uptake of 18 F-flutemetamol. These instances of disagreements between readers may correspond to equivocal cases in 11 C-PiB PET studies (3,4). Bias in judgment criteria for visually amyloidpositive findings in at least one of the five key regions may tend to lead to deviation from the quantitative measurement in these equivocal cases.…”

“…When using amyloid PET in clinical practice, qualitative determination of whether amyloid PET is positive or negative is performed by visual interpretation alone. In this binary classification, equivocal findings are inevitable and lead to interrater variability in visual interpretation (3,4) because each rater has his or her own experience and potential internal criteria. Equivocal findings should be avoided for determining the indication for disease-modifying drugs currently under development.…”

The feasibility of 11C‐PIB‐PET/CT for amyloid plaque burden: validation of the effectiveness of CT‐based partial volume correction

“…Generally in PET amyloid imaging, amyloid deposits are mainly evaluated by visual assessment by neuroradiologists. However, it has been reported that in amyloid PET, some equivocal findings are observed in interreading even among experienced neuroradiologists, and for such patients, SUVR tends to take intermediate values ranging from a typical value for AD to that for NL (Hosokawa et al., ; Payoux et al., ). The reason may be because PVE results in lower SUVR values despite sufficient amyloid deposits.…”