Evaluation of 18F-FDG PET with Bladder Irrigation in Patients with Uterine and Ovarian Tumors

Evaluation of ¹⁸F-FDG PET with Bladder Irrigation in Patients with Uterine and Ovarian Tumors

Koichi Koyama, MD¹, Terue Okamura, MD¹, Joji Kawabe, MD², Nozomi Ozawa, MD¹, Kenzi Torii, MD¹, Naohiko Umesaki, MD³, Masato Miyama, MD³, Hironobu Ochi, MD² and Ryusaku Yamada, MD¹

¹ Department of Radiology, Osaka City University School of Medicine, Osaka, Japan
² Department of Nuclear Medicine, Osaka City University School of Medicine, Osaka, Japan
³ Department of Obstetrics and Gynecology, Osaka City University School of Medicine, Osaka, Japan

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FIGURE 1. Typical case of malignant cervical cancer (patient 15). Patient was 83-y-old woman who consulted our hospital because of chief complaint of abnormal genital bleeding. (A) MRI revealed mass measuring 3 cm in diameter in cervical region of uterus. (B) ¹⁸F-FDG PET images showed marked ¹⁸F-FDG accumulation (SUV = 13.58) in region identical to that of mass detected by MRI. Although MRI showed urinary bladder at level similar to that of mass, ¹⁸F-FDG in urinary bladder was eliminated by bladder irrigation, which facilitated evaluation of PET images. Diagnosis of squamous cell carcinoma was established on basis of biopsy results.

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FIGURE 2. (A) Strong artifact caused by residual ¹⁸F-FDG activity in urinary bladder because of insufficient bladder irrigation (patient 33). Detection of tumor ¹⁸F-FDG accumulation was easy because slice level of tumor ¹⁸F-FDG accumulation was not same as slice level of artifact. (B) Residual ¹⁸F-FDG detected in left and right ureters after bladder irrigation (patient 24). One cannot easily differentiate ¹⁸F-FDG accumulation in ureter from that in metastatic lymph node by these axial images alone. (C) Reconstruction of coronal images facilitates diagnosis of ¹⁸F-FDG accumulation in ureters.

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FIGURE 3. Distribution of SUVs for malignant and nonmalignant cases. Significant difference existed between SUVs for malignant cases and those for nonmalignant cases. SUV cutoff of 2.0 was optimal for differentiating malignant cases from nonmalignant cases, but there was still only 1 false-positive case of ovarian fibroma.

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FIGURE 4. Patient was 43-y-old woman who consulted our hospital because of chief complaint of large palpable intrapelvic tumor (patient 39). MRI showed huge mass in front of sacrum and on right side of uterus. On basis of its location, mass was considered to be ovarian tumor. (A) This mass generally showed low intensity on T1- and T2-weighted images, suggesting that it contained fibrous components. However, high-intensity area was shown inside mass on T2-weighted image. MRI failed to differentiate whether mass was malignant or benign. (B) ¹⁸F-FDG PET showed heterogeneous ¹⁸F-FDG accumulation (SUV = 3.93) in this mass lesion, but high ¹⁸F-FDG accumulation was not seen in area of strong T2 signal. On basis of these findings, malignancy could not be excluded. After surgical treatment, mass was histologically diagnosed as fibroma. This case was the only false-positive case evaluated by SUV.

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FIGURE 5. Distribution of SUVs for each gynecologic tumor. SUVs for all malignant lesions were greater than 2.0. No significant difference existed between SUVs for uterine cervical carcinomas and those for uterine corpus carcinomas. BO = benign ovarian tumor or no malignancy; NRUCer = nonrecurrent uterine cervical carcinoma; OC = ovarian cancer; ROC = recurrent ovarian cancer; RUCer = recurrent uterine cervical carcinoma; RUCor = recurrent uterine corpus carcinoma; UCer = uterine cervical carcinoma; UCor = uterine corpus carcinoma.