Head and Neck Cancer: Detection of Recurrence with Three-dimensional Principal Components Analysis at Dynamic FDG PET1
Yoshimi Anzai, MD,
Satoshi Minoshima, MD, PhD,
Gregory T. Wolf, MD and
Richard L. Wahl, MD
1 From the Departments of Radiology (Y.A., R.L.W.), Internal Medicine (Nuclear Medicine) (S.M., R.L.W.), and Otolaryngology and Head and Neck Surgery (G.T.W.), the University of Michigan Medical Center, B1G505 University Hospital, 1500 E Medical Center Dr, Ann Arbor, MI 48109-0028. From the 1996 RSNA scientific assembly. Received April 1, 1998; revision requested June 25; revision received October 2; accepted December 16. Supported in part by National Institutes of Health grants CA 52880, MO1RR 00042, CA 53172, and CA 56731, and the High Technology funding initiative of the University of Michigan Medical Center and Clinical Research Center. Address reprint requests to R.L.W. (e-mail: rwahl@umich.edu).
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Figure 1. Schematic of PCA and its application to dynamic FDG PET in this study.
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Figure 2. PCA (PC1, PC2, PC4) in a patient with small cell carcinoma of the larynx, which was previously treated with irradiation and chemotherapy, who presented with a right-side neck mass. SUV image set (50–60 [minutes]) shows moderate FDG uptake in the nasal mucosa (N) and lymphoid tissue in the oropharynx (L) and postirradiation changes in the neck (R) and some intravascular activities. Tumor uptake (T) is also identifiable on the right side of the neck. Principal component image sets revealed focal tumor uptake with markedly suppressed physiologic soft-tissue uptake in the first component (PC1). Vascular activities are separated in the fourth component (PC4). The second component (PC2) represents other noise variances.
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Figure 3. PCA (PC1–PC3) in a patient with laryngeal cancer, which had been treated with irradiation, who presented with sore throat and hoarseness. SUV image (50–60 [minutes]) shows diffuse mildly increased FDG uptake in the previously irradiated larynx (L), but the tumor is not conspicuous. The first component (PC1) is the vascular component (V). The second component (PC2) is the tumor component, which corresponds to a focus of recurrent laryngeal tumor (T) in the true vocal cord that extends into the anterior commissure. This tumor component image clearly separates tumor from residual FDG uptake in the postirradiation changes. In the time-activity curve, there is a small dip (arrow) that most likely relates to noise or patient motion. The third component (PC3) represents residual noises without apparent physiologic correlates.
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Figure 4. PCA (PC1–PC3) in a patient with adenoid cystic carcinoma of the right cheek and parotid gland that had been partially resected. The patient presented with swelling of the right cheek. SUV image (50–60 [minutes]) shows very mild radiotracer uptake in the right parotid gland (P). The first component image (PC1) shows gradual increase in FDG uptake, which is expected to be tumor component, corresponding to the cerebellum (C). Tumor (T) was classified into the second component image (PC2), which shows initial increase followed by gradual decrease in FDG uptake. At PCA, this tumor was not detected in the component of increasing activity (PC1) because the kinetic behavior of this particular tumor was similar to that of residual soft tissue. The third component (PC3) represents residual noises without apparent physiologic correlates.
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Copyright © 1999 by the Radiological Society of North America.
