Consistency and prognostic value of preoperative staging and postoperative pathological staging using 18F-FDG PET/MRI in patients with non-small cell lung cancer.

OBJECTIVE: In recent years, positron emission tomography/magnetic resonance imaging (PET/MRI) has been clinically used as a method to diagnose non-small cell lung cancer (NSCLC). This study aimed to evaluate the concordance of staging and prognostic ability of NSCLC patients using thin-slice computed tomography (CT) and 18F-fluorodeoxyglucose (FDG) PET/MRI. METHODS: This retrospective study was performed on consecutive NSCLC patients who underwent both diagnostic CT and 18F-FDG PET/MRI before surgery between November 2015 and May 2019. The cTNM staging yielded from PET/MRI was compared with CT and pathological staging, and concordance was investigated, defining pathological findings as reference. To assess the prognostic value of disease-free survival (DFS) and overall survival (OS), we dichotomized the typical prognostic factors and TNM classification staging (Stage I vs. Stage II or higher). Kaplan-Meier curves derived by the log-rank test were generated, and univariate and multivariate analyses were performed to identify the factors associated with DFS and OS. RESULTS: A total of 82 subjects were included; PET/MRI staging was more consistent (59 of 82) with pathological staging than with CT staging. There was a total of 21 cases of CT and 11 cases of PET/MRI that were judged as cStage I, but were actually pStage II or pStage III. CT tended to judge pN1 or pN2 as cN0 compared to PET/MRI. There was a significant difference between NSCLC patients with Stage I and Stage II or higher by PET/MRI staging as well as prognosis prediction of DFS by pathological staging (P < 0.001). In univariate analysis, PET/MRI, CT, and pathological staging (Stage I or lower vs. Stage II or higher) all showed significant differences as prognostic factors of recurrence or metastases. In multivariate analysis, pathological staging was the only independent factor for recurrence (P = 0.009), and preoperative PET/MRI staging was a predictor of patient survival (P = 0.013). CONCLUSIONS: In NSCLC, pathologic staging was better at predicting recurrence, and preoperative PET/MRI staging was better at predicting survival. Preoperative staging by PET/MRI was superior to CT in diagnosing hilar and mediastinal lymph-node metastases, which contributed to the high concordance with pathologic staging.

Magnetic Resonance Imaging and Histopathology in a Case of Pleomorphic Adenoma of a Minor Salivary Gland in the Nasal Cavity.

BACKGROUND Pleomorphic adenoma of the salivary gland is a common benign tumor of the parotid gland. However, pleomorphic adenoma arising in the minor salivary glands, including the nasopharynx, is uncommon. This report is of a case of nasal pleomorphic adenoma in which the preoperative imaging findings were consistent with the histological features of pleomorphic adenoma of the minor salivary gland, which differs from that of pleomorphic adenoma of the major salivary gland. CASE REPORT A 56-year-old Japanese man was referred to the department of otolaryngology following nasal endoscopy performed at a referral center that identified a right nasal mass. The findings of contrast-enhanced magnetic resonance imaging (MRI) were consistent with a pleomorphic adenoma arising in the nasal septum. Needle biopsy and histology confirmed the diagnosis of pleomorphic adenoma. The tumor was resected using endoscopic surgery, and the histology confirmed the diagnosis of pleomorphic adenoma covered by normal nasal mucosa. CONCLUSIONS This case showed that pleomorphic adenoma arising in the nasal minor salivary gland had typical MRI and histological findings and was a submucosal lesion. Preoperative MRI supported the approach to surgical resection to ensure complete excision.

Measurement of cerebral vascular reserves with I-123 IMP SPECT without an arterial input function using the microsphere model and radiopharmaceutical dose calibration.

OBJECTIVES: Cerebral vascular reserve (CVR) is an important indicator for the management of and therapy for cerebral arterial occlusive disease (CAOD). Vasodilatory function is measured using the standard IMP-ARG method. The IMP autoradiography (IMP-ARG) method employed here uses a standardized input function, which was derived from 12 patients between 31 and 71 years of age. Because the population of elderly patients continues to increase in Japan, additional therapies are required to assess CVR in elderly patients with chronic cardiopulmonary disease or a history of smoking, in particular. Despite its popularity, alternatives to the IMP-ARG method are necessary. Here, we proposed the microsphere (MS) method without an input function. METHOD: Using this method and the IMP-ARG method, we measured the CVRs of 18 CAOD patients. RESULTS: The CVRs derived with these two methods were significantly and linearly correlated (r = 0.89, p < 0.01). CVRs categorized by severity were also found to correspond between the two methods (κ = 0.87). CONCLUSIONS: Thus, the method proposed here may serve as a supplemental to and be compatible with the IMP-ARG method for the assessment of CVR. Furthermore, the two methods, when used in conjunction, may result in less error than either would alone.

Evaluation of biliary anatomy in the caudate lobe using drip infusion cholangiography-computed tomography.

PURPOSE: This study aimed to retrospectively evaluate the caudate branches (CBs), which are bile ducts originating from the caudate lobe (CL), using drip infusion cholangiography with computed tomography (DIC-CT). METHODS: The confluence patterns of CBs were evaluated in 185 adult patients undergoing DIC-CT. The following bile duct features were evaluated: (a) number of depicted CBs; (b) identification of the caudate portion from which the CBs were derived; (c) identification of the confluence site of a CB; and (d) whether there was a difference in the confluence site of the CBs depending on the position of the right posterior hepatic duct (RPHD) and the portal vein (PV). RESULTS: DIC-CT enabled detection of a total of 640 bile ducts from the CL in 185 patients, and the total number of CBs from the Spiegel lobe (SP), the paracaval portion, and the caudate process (CP) were 347 (54.2%), 112 (17.5%), and 181 (28.2%), respectively. In the SP, over 60% of CBs joined the left hepatic duct system (LHDS). The positional relationship between the RPHD and the PV was divided into a supra-portal course (n = 168) and an infra-portal course (n = 17). The number of CBs joining the LHDS was significantly different between a supra-portal course and an infra-portal course (p = 0.0484). CONCLUSION: CBs were depicted by DIC-CT in 98.9% of the subjects, and a detailed evaluation was possible. The number of CBs joining the LHDS was associated with the position of the RPHD and the PV.

Improvement in the measurement error of the specific binding ratio in dopamine transporter SPECT imaging due to exclusion of the cerebrospinal fluid fraction using the threshold of voxel RI count.

OBJECTIVE: In Japan, the Southampton method for dopamine transporter (DAT) SPECT is widely used to quantitatively evaluate striatal radioactivity. The specific binding ratio (SBR) is the ratio of specific to non-specific binding observed after placing pentagonal striatal voxels of interest (VOIs) as references. Although the method can reduce the partial volume effect, the SBR may fluctuate due to the presence of low-count areas of cerebrospinal fluid (CSF), caused by brain atrophy, in the striatal VOIs. We examined the effect of the exclusion of low-count VOIs on SBR measurement. METHODS: We retrospectively reviewed DAT imaging of 36 patients with parkinsonian syndromes performed after injection of 123I-FP-CIT. SPECT data were reconstructed using three conditions. We defined the CSF area in each SPECT image after segmenting the brain tissues. A merged image of gray and white matter images was constructed from each patient's magnetic resonance imaging (MRI) to create an idealized brain image that excluded the CSF fraction (MRI-mask method). We calculated the SBR and asymmetric index (AI) in the MRI-mask method for each reconstruction condition. We then calculated the mean and standard deviation (SD) of voxel RI counts in the reference VOI without the striatal VOIs in each image, and determined the SBR by excluding the low-count pixels (threshold method) using five thresholds: mean-0.0SD, mean-0.5SD, mean-1.0SD, mean-1.5SD, and mean-2.0SD. We also calculated the AIs from the SBRs measured using the threshold method. We examined the correlation among the SBRs of the threshold method, between the uncorrected SBRs and the SBRs of the MRI-mask method, and between the uncorrected AIs and the AIs of the MRI-mask method. RESULTS: The intraclass correlation coefficient indicated an extremely high correlation among the SBRs and among the AIs of the MRI-mask and threshold methods at thresholds between mean-2.0D and mean-1.0SD, regardless of the reconstruction correction. The differences among the SBRs and the AIs of the two methods were smallest at thresholds between man-2.0SD and mean-1.0SD. CONCLUSION: The SBR calculated using the threshold method was highly correlated with the MRI-SBR. These results suggest that the CSF correction of the threshold method is effective for the calculation of idealized SBR and AI values.

Spontaneously Ruptured Paraovarian Tumor of Borderline Malignancy with Extremely Elevated Serum Carbohydrate Antigen 125 (CA125) Levels: A Comparison of the Imaging and Pathological Features.

BACKGROUND Paraovarian cysts are common and are generally benign; however, they are frequently misdiagnosed as being of ovarian origin. Conversely, paraovarian tumors of borderline malignancy are extremely rare. Especially, no cases of spontaneous rupture have been reported, and all previous reports had normal serum carbohydrate antigen (CA) 125 level. As for imaging findings, the presence of papillary projections in the lumen of paraovarian tumors does not always indicate malignancy or benignancy, which makes the preoperative distinction difficult. CASE REPORT We report a case involving a 22-year-old Asian woman with a spontaneously ruptured paraovarian tumor of borderline malignancy. The serum CA125 concentration was extremely elevated, at 28,831 U/mL. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a collapsed unilocular cystic lesion with multiple papillary projections. On MRI, the papillary projections showed two different patterns, which corresponded to the pathological findings. CONCLUSIONS Ruptured paraovarian tumors of borderline malignancy may show extremely high serum CA125 values. Furthermore, specific MRI findings may be useful in evaluating the malignancy of paraovarian tumors.