Clinical Implications of FDG-PET in Pancreatic Ductal Adenocarcinoma Patients Treated with Neoadjuvant Therapy.

PURPOSE: To evaluate the clinical significance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with pancreatic ductal adenocarcinoma who underwent neoadjuvant therapy. METHODS: Among 285 consecutive patients who underwent pancreatic resection for pancreatic ductal adenocarcinoma between 2015 and 2021, 86 who underwent preoperative 18F-fluorodeoxyglucose positron emission tomography/computed tomography after completion of neoadjuvant treatment were reviewed. Among preoperative factors, including post-treatment maximum standardized uptake value, predictors of early recurrence and poor prognosis were identified using multivariate analysis for decision making in surgery. RESULTS: Nineteen (22%) patients with pancreatic ductal adenocarcinoma demonstrated high maximum standardized uptake (≥ 4.5). High post-treatment maximum standardized uptake (≥ 4.5) predicted early recurrence within 6 months after surgery and correlated with shorter recurrence-free survival. Elevated post-treatment CA19-9 level (> 37 U/ml) and maximum standardized uptake ≥ 4.5 were independent prognostic factors. Post-treatment, a high maximum standardized uptake value indicated a poorer prognosis than a low maximum standardized uptake value in both patients with elevated CA19-9 and normal CA19-9 levels. The median overall survival in patients with elevated post-treatment CA19-9 and high maximum standardized uptake was only 17 months; 67% experienced early recurrence. Dynamic changes in maximum standardized uptake during neoadjuvant therapy were correlated with pathological response to neoadjuvant therapy, but not with radiological response or change in CA19-9 level. CONCLUSIONS: Post-treatment assessment using maximum standardized uptake value is useful for stratifying patients with pancreatic ductal adenocarcinoma who will benefit from surgery. Instead of subsequent curative resection, additional neoadjuvant therapy should be considered in patients with a persistently high maximum standardized uptake value.

Utility of FDG PET at the Initial Radioiodine Therapy in Differentiated Thyroid Cancer.

BACKGROUND/AIM: Differentiated thyroid cancer (DTC) has a good prognosis, except in the case of patients with radioiodine therapy (RIT)-refractory cancer. However, since DTC is essentially a slowly progressing cancer, it is usually judged to be a DTC with a poor prognosis after multiple RITs and yearly follow-up with echo, computed tomography (CT), and serum thyroglobulin values. This study investigated whether fluorodeoxyglucose-positron emission tomography/CT (FDG PET/CT) combined with initial RIT could identify early-stage patients with poor prognosis. PATIENTS AND METHODS: We evaluated 100 patients with high-risk DTC who underwent total thyroidectomy and received RIT at our institution. We analyzed the clinical outcomes of patients and 18F-FDG accumulation using univariate and multivariate Cox proportional hazards regression models. RESULTS: The 10-year overall survival (OS) was 87.9%, with no significant difference in OS between 18F-FDG accumulation at pre-total or near-total thyroidectomy (NTT) (p=0.180) and 131I accumulation at initial RIT (p=0.577). However, 18F-FDG positive patients had a significantly worse prognosis than negative patients (p=0.005) at initial RIT. CONCLUSION: 18F-FDG PET/CT plays an important role in both the diagnosis and prognostic prediction of RIT refractory disease in DTC patients. 18F-FDG PET/CT can be a useful tool particularly at the time of initial RIT since the 18F-FDG accumulation enables the screening of high-risk DTC with poor prognosis at a very early time stage.

Usefulness of semi-quantitative analysis in 123I metaiodobenzylguanidine SPECT/CT for the differentiation of pheochromocytoma and cortical adenoma.

OBJECTIVE: 123I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of pheochromocytomas (PHEOs), but some PHEOs are difficult to differentiate from cortical adenoma (CA) or normal adrenal uptake by visual evaluation alone. A new semi-quantitative analysis using 123I MIBG SPECT/CT is thus expected. Herein, we introduce the tumor-to-liver count ratio (T/L) and the tumor-to-muscle count ratio (T/M). METHODS: We examined the cases of 21 patients with PHEOs (10 males, 11 females; age 24-80, median 61 years) and 23 patients with CA (15 males and 8 females, age 30-78, median 58 years). The visual scoring based on 123I MIBG planar images (planar score) and SPECT images (SPECT score) was used as the conventional evaluation. Using 123I MIBG SPECT/CT findings, we calculated the semi-quantitative values of the count ratio using the maximum or mean count of the tumor and the liver or muscle as the reference organ (T/Lmax, T/Lmean, T/Mmax and T/Mmean). Each evaluation of the PHEOs and CAs was compared, and the diagnosing performance was evaluated based on an ROC analysis. RESULTS: The area under curve (AUC) values were as follows: the planar score, 0.833; SPECT score, 0.813; T/Lmax, 0.986; T/Lmean, 0.975; T/Mmax, 0.955; and T/Mmean, 0.933. The AUC for T/Mmax was significantly higher than those of the planar score, and SPECT score by ROC analysis (p < 0.01 each). CONCLUSION: The semi-quantitative value of 123I MIBG SPECT/CT is more useful than the conventional visual evaluation for differentiating PHEOs from CAs.

Compared to conventional PET/CT scanners, silicon-photomultiplier-based PET/CT scanners show higher arterial 18F-FDG uptake in whole-body 18F-FDG-PET/CT.

OBJECTIVES: To clarify differences in arterial 18F-FDG (fluorodeoxyglucose) uptake between silicon photomultiplier (SiPM)-based and conventional PET/CT scanners, and to compare clinical and phantom results. PATIENTS AND METHODS: Twenty-six patients with lung tumours underwent serial SiPM-based and conventional PET/CT scans on the same day. We compared the target-to-background ratios [TBRsi (SiPM), TBRc (conventional)] and the percentage difference between TBRsi and TBRc (ΔTBR) in the carotid artery, aorta and peripheral arteries. The correlation between ΔTBR and vessel size was also investigated. In the carotid artery, active segment analyses were performed with the threshold (TBR ≥1.6), and we compared each scanner's ratio of active segments and TBR values. We compared the clinical results with the recovery coefficients (RCs). RESULTS: The TBRsi was significantly higher than the TBRc in the carotid artery, aorta and peripheral arteries (1.63 ± 0.22 vs. 1.43 ± 0.22, 1.65 ± 0.19 vs. 1.53 ± 0.15 and 1.37 ± 0.31 vs. 1.11 ± 0.27, mean ± SD, P ≤ 0.0001 for all), and the peripheral arteries showed the highest ΔTBR (24.4 ± 16.8%). The small (10-15 mm) vessels (26.9 ± 15.9%) showed significantly higher ΔTBRs than the larger vessels (7.3 ± 8.5% for 15-20 mm, 8.0 ± 12.8% for ≥20 mm, P < 0.0001 for both). The carotid artery showed significantly higher ratios of active segment (54.5 vs. 20.5%, P < 0.0001) and TBR values (1.85 ± 0.25 vs. 1.76 ± 0.15, P = 0.0006) for TBRsi vs. TBRc. The differences in RCs were similar to those of ΔTBR for each vessel size. CONCLUSIONS: SiPM-based PET/CT scanners showed higher arterial 18F-FDG uptake (especially in vessels <15 mm) than conventional scanners, and the threshold TBR ≥1.6 is not applicable for the carotid artery for SiPM-based PET/CT systems.

123I metaiodobenzylguanidine (MIBG) uptake predicts early relapse of neuroblastoma using semi-quantitative SPECT/CT analysis.

OBJECTIVE: 123I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of neuroblastoma (NB). MIBG uptake is correlated with norepinephrine transporter expression; hence, it is expected that high-MIBG tumors would be more highly differentiated and have a better prognosis than those with lower expression. We have introduced a method of assessing MIBG accumulation semi-quantitatively using SPECT/CT fusion images. The purpose of this study was to evaluate the relationship of 123I MIBG uptake measured by semi-quantitative values of SPECT/CT and early relapse of NB. METHODS: We studied the cases of 11 patients (5 males and 6 females, age 5-65 months, median age 20 months) with histopathologically proven NB between April 2010 and March 2015. The early-relapse group was defined as patients who had relapsed within 3 years after the first 123I MIBG SPECT/CT exam. Other patients were classified as the delay-relapse group. Uptake of MIBG was evaluated using the count ratio of tumor and muscles. T/Mmax and T/Mmean were defined as follows: T/Mmax = max count of tumor/max count of muscle, T/Mmean = mean count of tumor/mean count of muscle. RESULTS: The average T/Mmean values of the early-relapse group and delay-relapse group were 2.65 ± 0.58 and 7.66 ± 2.68, respectively. The T/Mmean values of the early-relapse group were significantly lower than those of delay-relapse group (p < 0.05). The average T/Mmax of the early-relapse group and delay-relapse group were 8.86 ± 3.22 and 16.20 ± 1.97, respectively. There was no significant difference in T/Mmax values between the two groups. CONCLUSIONS: Low 123I MIBG uptake using semi-quantitative SPECT/CT analysis was correlated with early relapse of NB.

Prognostic outcome and complications of sentinel lymph node navigation surgery for early-stage cervical cancer.

BACKGROUND: To evaluate the prognostic outcome and surgical complications in patients with early-stage cervical cancer who underwent sentinel node navigation surgery (SNNS) for hysterectomy or trachelectomy. METHODS: A total of 139 patients who underwent SNNS using 99mTc phytate between 2009 and 2015 were evaluated. No further lymph node dissection was performed when intraoperative analysis of the sentinel lymph nodes (SLNs) was negative for metastasis. We compared the surgical complications between the SNNS group and 67 matched patients who underwent pelvic lymph node dissection (PLND) after SLN mapping between 2003 and 2008. We also examined the clinical outcomes in the SNNS group. RESULTS: The mean number of detected SLNs was 2.5 per patient. Fourteen of the 139 patients in the SNNS group underwent PLND based on the intraoperative SLN results. The amount of blood loss, the operative time, and the number of perioperative complications were significantly less in the SNNS group than in the matched PLND group. There was no recurrence during a follow-up period ranging from 2 to 88 months (median 40 months) in the SNNS group. CONCLUSIONS: Using SNNS for early-stage cervical cancer is safe and effective and does not increase the recurrence rate. A future multicenter trial is warranted.

Optimal monochromatic color combinations for fusion imaging of FDG-PET and diffusion-weighted MR images.

OBJECTIVE: To investigate the optimal monochromatic color combination for fusion imaging of FDG-PET and diffusion-weighted MR images (DW) regarding lesion conspicuity of each image. METHODS: Six linear monochromatic color-maps of red, blue, green, cyan, magenta, and yellow were assigned to each of the FDG-PET and DW images. Total perceptual color differences of the lesions were calculated based on the lightness and chromaticity measured with the photometer. Visual lesion conspicuity was also compared among the PET-only, DW-only and PET-DW-double positive portions with mean conspicuity scores. Statistical analysis was performed with a one-way analysis of variance and Spearman's rank correlation coefficient. RESULTS: Among all the 12 possible monochromatic color-map combinations, the 3 combinations of red/cyan, magenta/green, and red/green produced the highest conspicuity scores. Total color differences between PET-positive and double-positive portions correlated with conspicuity scores (ρ = 0.2933, p < 0.005). Lightness differences showed a significant negative correlation with conspicuity scores between the PET-only and DWI-only positive portions. Chromaticity differences showed a marginally significant correlation with conspicuity scores between DWI-positive and double-positive portions. CONCLUSIONS: Monochromatic color combinations can facilitate the visual evaluation of FDG-uptake and diffusivity as well as registration accuracy on the FDG-PET/DW fusion images, when red- and green-colored elements are assigned to FDG-PET and DW images, respectively.

A Functional Scoring System Based on Salivary Gland Scintigraphy for Evaluating Salivary Gland Dysfunction Secondary to 131I therapy in Patients with Differentiated Thyroid Carcinoma.

INTRODUCTION: Radioiodine therapy with 131I (131I therapy) after total or near-total thyroidectomy has been established as an effective treatment for Differentiated Thyroid Carcinoma (DTC), but can induce dry mouth symptoms by salivary gland damage and impair the patients' quality of life. AIM: To propose a functional scoring system based on Salivary Gland Scintigraphy (SGS) findings that evaluates development of salivary gland dysfunction secondary to 131I therapy in patients with DTC. MATERIALS AND METHODS: This retrospective study evaluated the records of 279 DTC patients who underwent SGS after one or more round(s) of 131I therapy, using 370 MBqof 99mTc-pertechnetate. The SGS results were assessed using a novel functional scoring system in the Parotid Glands (PGs) and Submandibular Glands (SMGs) according to visual evaluations based on a three-point uptake score, Washout Rate (%WR) score after lemon-juice stimulation, and functional score. The scores were compared among pre treatment, low-dose (<10 GBq), and high-dose (>10 GBq) groups and among pre treatment, symptom-positive, and symptom-negative groups. Risk factors for dry mouth were analyzed by univariate and multivariate logistic regression analyses. RESULTS: Dry mouth symptoms developed in 15.4% of the DTC patients after 131I therapy. The three-point uptake, %WR, and functional scores in both the PG and SMG were statistically significant between low-dose and high-dose groups, and between symptom-positive and symptom-negative groups. The PG/SMG functional scores were independent risk factors for dry mouth (odds ratio, 0.03 and 0.0007 respectively). CONCLUSION: SGS-based PG and SMG functional scores were effective biomarkers to objectively evaluate salivary gland dysfunction, with the high strength of association with dry mouth symptoms.

Metabolic Tumor Volume by 18F-FDG PET/CT Can Predict the Clinical Outcome of Primary Malignant Spine/Spinal Tumors.

BACKGROUND AND PURPOSE: Primary malignant spine/spinal tumors (PMSTs) are rare and life-threatening diseases. In this study, we demonstrated the advantage of volume-based 18F-FDG PET/CT metabolic parameter, metabolic tumor volume (MTV), for assessing the aggressiveness of PMSTs. MATERIALS AND METHODS: We retrospectively reviewed 27 patients with PMSTs and calculated SUVmax, MTV, and total lesion glycolysis (TLG) to compare their accuracy in predicting progression-free survival (PFS) and overall survival (OS) by receiver operating characteristic (ROC) curve analysis. Univariate and multivariate analyses were used to compare the reliability of the metabolic parameters and various clinical factors. RESULTS: MTV exhibited greater accuracy than SUVmax or TLG. The cut-off values for PFS and OS derived from the AUC data were MTV 45 ml and 83 ml and TLG 250 SUV⁎ml and 257 SUV⁎ml, respectively. MTV above cut-off value, but not TLG, was identified as significant prognostic factor for PFS by log-lank test (p = 0.04). In addition, MTV was the only significant predictive factors for PFS and OS in the multivariate analysis. CONCLUSIONS: MTV was a more accurate predictor of PFS and OS in PMSTs compared to TLG or SUVmax and helped decision-making for guiding rational treatment options.

The Efficiency of Respiratory-gated 18F-FDG PET/CT in Lung Adenocarcinoma: Amplitude-gating Versus Phase-gating Methods.

OBJECTIVES: In positron emission tomography (PET) studies, thoracic movement under free-breathing conditions is a cause of image degradation. Respiratory gating (RG) is commonly used to solve this problem. Two different methods, i.e., phase-gating (PG) and amplitude-gating (AG) PET, are available for respiratory gating. It is important to know the strengths and weaknesses of both methods when selecting an RG method for a given patient. We conducted this study to clarify whether AG or PG is preferable for measuring fluorodeoxyglucose (FDG) accumulation in lung adenocarcinoma and to investigate patient conditions which are most suitable for AG and PG methods. METHODS: A total of 31 patients (11 males, 20 females; average age: 70.1±11.6 yrs) with 44 lung lesions, diagnosed as lung adenocarcinoma between April 2012 and March 2013, were investigated. Whole-body FDG-PET/CT scan was performed with both PG and AG methods in all patients. The maximum standardized uptake value (SUVmax) of PG, AG, and the control data of these two methods were measured, and the increase ratio (IR), calculated as IR(%)= (Post - Pre)/Pre × 100, was calculated. The diameter and position of lung lesions were also analyzed. We defined an 'effective lesion' of PG (or AG) as a lesion which showed a higher IR compared to AG (or PG). 8 (25.8%). RESULTS: The average SUVmax and average IR were 8.99±7.94 and %21.4±25.6 in PG and 7.60±6.70 and %4.0±14.4 in AG, respectively. Although there was no significant difference between the average SUVmax of PG and AG (P=0.09), the average IR of PG was significantly higher than that of AG (P<0.01). The number of PG- and AG-effective lesions was 32 (72.7%) and 12 (28.3%), respectively. There was no significant difference in the average diameter or position of the lesions between the PG- and AG-effective lesions. There were 23 (74.2%) PG-effective and 8 (25.8%) AG-effective patients. No significant difference was observed in sex or age between PG- and AG-effective patients. CONCLUSION: The PG method was more effective for measuring FDG accumulation of lung lesions under free-breathing conditions in comparison with the AG method.

Influence of the Different Primary Cancers and Different Types of Bone Metastasis on the Lesion-based Artificial Neural Network Value Calculated by a Computer-aided Diagnostic System, BONENAVI, on Bone Scintigraphy Images.

OBJECTIVES: BONENAVI, a computer-aided diagnostic system, is used in bone scintigraphy. This system provides the artificial neural network (ANN) and bone scan index (BSI) values. ANN is associated with the possibility of bone metastasis, while BSI is related to the amount of bone metastasis. The degree of uptake on bone scintigraphy can be affected by the type of bone metastasis. Therefore, the ANN value provided by BONENAVI may be influenced by the characteristics of bone metastasis. In this study, we aimed to assess the relationship between ANN value and characteristics of bone metastasis. METHODS: We analyzed 50 patients (36 males,14 females; age range: 87-42 yrs median age:72.5 yrs) with prostate, breast, or lung cancer who had undergone bone scintigraphy and were diagnosed with bone metastasis (32 cases of prostate cancer, nine cases of breast cancer, and nine cases of lung cancer). Those who had received systematic therapy over the past years were excluded. Bone metastases were diagnosed clinically, and the type of bone metastasis (osteoblastic, mildly osteoblastic, osteolytic, and mixed components) was decided visually by the agreement of two radiologists. We compared the ANN values (case-based and lesion-based) among the three primary cancers and four types of bone metastasis. RESULTS: There was no significant difference in case-based ANN values among prostate, breast, and lung cancers. However, the lesion-based ANN values were the highest in cases with prostate cancer and the lowest in cases of lung cancer (median values: prostate cancer, 0.980; breast cancer 0.909; and lung cancer, 0.864). Mildly osteoblastic lesions showed significantly lower ANN values than the other three types of bone metastasis (median values: osteoblastic,; 0.939 mildly osteoblastic; 0.788, mixed type; 0.991, and osteolytic. 0.969) The possibility of a lesion-based ANN value below 0.5 was %10.9 for bone metastasis in prostate cancer, %12.9 for breast cancer, and %37.2 for lung cancer. The corresponding possibility were %14.7 for osteoblastic metastases, %23.9 for mildly osteoblastic metastases, %7.14 for mixed-type metastases, and %16.0 for osteolytic metastases. CONCLUSION: The lesion-based ANN values calculated by BONENAVI can be influenced by the type of primary cancer and bone metastasis.

Association between Volumetric Analysis of Lung Metastases on F-18-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography and Short-term Progression after I-131 Therapy for Differentiated Thyroid Carcinoma.

PURPOSE: Lung metastases (LMs) and their radioiodine uptake affect prognosis in patients with differentiated thyroid carcinoma (DTC). We herein investigate the value of metabolic tumor volume (MTV) in LMs on positron emission tomography/computed tomography (PET/CT) using 2-[F-18]-fluoro-2-deoxy-D-glucose (F-18 FDG PET/CT) in predicting short-term progression after initial I-131 therapy in DTC patients. MATERIALS AND METHODS: We retrospectively evaluated 111 DTC patients with LMs. Diagnostic CT and I-131 scintigraphy were performed within 1 week of I-131 therapy. Maximum standardized uptake value (SUVmax) and total MTV (MTVtotal) were compared between patients with I-131-positive and I-131-negative LMs and between patients with and without short-term progression. Correlation analyses were performed between F-18 FDG PET/CT parameters and thyroglobulin (TG) level, and predictive factors for short-term progression were analyzed by logistic regression and receiver operating characteristic curve analysis. RESULTS: Patients with short-term progression had significantly higher SUVmax and MTVtotal than those without. TG levels were significantly correlated with SUVmax (r = 0.21) and MTVtotal (r = 0.51) after I-131 therapy. MTVtotal showed significant association (χ2 = 16.5, odds ratio = 0.02) with short-term progression after initial I-131 therapy and had the highest predictive value of all the putative risk factors. CONCLUSIONS: MTVtotal in LMs on F-18 FDG PET/CT is an independent predictive factor with a high predictive value for short-term progression of DTC after initial I-131 therapy. It is recommended that F-18 FDG PET/CT be performed before planning therapy during the evaluation of DTC patients with LM.

Impact of patient age on the iodine/FDG "flip-flop" phenomenon in lung metastasis from thyroid cancer.

OBJECTIVES: Radioiodine therapy is an effective treatment for lung metastasis from thyroid cancer. However, cases of lung metastasis without iodine uptake are often encountered. In such cases, FDG accumulation in lung lesions is often observed. There is a reverse relationship between iodine and FDG accumulation in thyroid cancer lesions, the so-called "flip-flop" phenomenon. The aim of this study was to assess the relationship between patient age and the occurrence of the flip-flop phenomenon. METHODS: Eighty-six patients who underwent radioiodine therapy for lung metastasis were studied retrospectively (age 17-73 years; median 60 years; males:females 22:64). We compared the clinical data and imaging findings (size and FDG uptake of lung nodules) between patients with (n = 44) and without (n = 42) iodine uptake in lung metastasis. RESULTS: Significantly more young patients showed iodine accumulation in lung metastasis than old patients (p = 0.0025). Lung metastases with larger size or greater FDG uptake showed no iodine uptake more frequently with significant difference (p = 0.015 and <0.001, respectively). Among patients with FDG uptake in the lung metastasis, 57.1 % of young patients (<60 years) and 24.3 % of the old patients (≥60 years) showed iodine uptake (p = 0.0029). CONCLUSIONS: Higher patient age and lung nodules with large size or FDG accumulation are negative factors for iodine accumulation in lung metastases from thyroid cancer. In addition, our results show that young patients have a greater likelihood of iodine uptake even when FDG accumulates in lung metastasis, in contrast to old patients.

Diagnostic utility of intravoxel incoherent motion mr imaging in differentiating primary central nervous system lymphoma from glioblastoma multiforme.

PURPOSE: To evaluate the diagnostic performance of intravoxel incoherent motion (IVIM) MR imaging and 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphoma (PCNSL) from glioblastoma multiforme (GBM). MATERIALS AND METHODS: Fifty patients, 17 with PCNSL and 33 with GBM, were retrospectively studied. From the 3 Tesla IVIM data, the perfusion fraction (f) and diffusion coefficient (D) were obtained. In addition, the maximum standard uptake value (SUVmax ) was obtained from the FDG-PET data. Each of the three parameters was compared between PCNSL and GBM using Mann-Whitney U-test. The performance in discriminating between PCNSL and GBM was evaluated using receiver-operating characteristics analysis and area-under-the-curve (AUC) values for the three parameters. RESULTS: The fmax and Dmin values were significantly higher in GBM than in PCNSL (P < 0.01 and P < 0.0001, respectively). In addition, the SUVmax value was significantly lower in GBM than in PCNSL (P < 0.0005). The AUC values for fmax , Dmin , and SUVmax were 0.756, 0.905, and 0.857, respectively. The combination of the fmax and Dmin increased the diagnostic performance (AUC = 0.936) of fmax (P < 0.05), but this value was not significantly different from the values for Dmin (P = 0.30). CONCLUSION: IVIM-MR imaging noninvasively provides useful quantitative information in distinguishing between PCNSL and GBM. J. Magn. Reson. Imaging 2016;44:1256-1261.

Esophagectomy-related thoracic duct injury detected by lymphoscintigraphy with 99mTc-diethylenetriamine pentaacetic acid-human serum albumin: report of a case.

Chylothorax is an uncommon but potentially life-threatening complication of esophagectomy. A 72-year-old man underwent thoracoscopy-assisted subtotal esophagectomy and reconstruction with a gastric tube, through a retrosternal route, after preoperative chemoradiotherapy. Chylothorax was detected after starting enteral feeding on postoperative day (POD) 7. Despite conservative therapy such as fasting, total parenteral nutrition, and octreotide administration, massive fluid drainage continued. On POD 19, lymphoscintigraphy with (99m)Tc-diethylenetriamine pentaacetic acid-human serum albumin (HSA-D) was performed and the site of leakage was detected at the level of the fourth thoracic vertebra. On POD 23, the thoracic duct was ligated, following which the volume of chylothorax decreased. Lymphoscintigraphy 12 days after the reoperation showed no leakage from the thoracic duct. We recommend lymphoscintigraphy with (99m)Tc-HSA-D for locating the chyle leakage site and helping decide about the operative indication.

Abnormality in Wnt signaling is causatively associated with oxidative stress-induced intestinal tumorigenesis in MUTYH-null mice.

MUTYH is a DNA glycosylase that excises adenine paired with 8-oxoguanine to prevent mutagenesis in mammals. Biallelic germline mutations of MUTYH have been found in patients predisposed to a recessive form of familial adenomatous polyposis (MAP: MUTYH-associated polyposis). We previously reported that Mutyh-deficient mice showed a high susceptibility to spontaneous and oxidative stress-induced intestinal adenoma/carcinoma. Here, we performed mutation analysis of the tumor-associated genes including Apc, Ctnnb1, Kras and Trp53 in the intestinal tumors of Mutyh-deficient mice. In the 62 tumors, we identified 25 mutations in Apc of 18 tumors and 36 mutations in Ctnnb1 of 36 tumors. Altogether, 54 out of the 62 tumors (87.1%) had a mutation in either Apc or Ctnnb1; no tumor displayed mutations simultaneously in the both genes. Similar to MAP, 60 out of 61 mutations (98.3%) were identified as G:C to T:A transversions of which 85% occurred at either AGAA or TGAA sequences. Immunohistochemical analyses revealed the accumulation of ß-catenin in the nuclei of tumors. No mutation was found in either Kras or Trp53 in the tumors. These results indicate that the uncontrolled activation of Wnt signaling pathway is causatively associated with oxidative stress-induced intestinal tumorigenesis in the Mutyh-deficient mice.

Nabothian cyst a predominant cause of false-positive iodine uptake in uterus: comparison of SPECT/CT and pelvic MRI.

PURPOSE: Many cases of unexpected radioiodine uptake have been reported, including physiological uptake in healthy tissue and in both benign and malignant nonthyroidal lesions. However, iodine uptake in the uterus has not been well assessed. In this article, we systemically analyzed iodine uptake in the uterus and identified the site in which uptake occurred. MATERIALS AND METHODS: Seventy-six female patients who underwent SPECT/CT from neck to pelvis were included in this study; 5 patients with uterine uptake received pelvic MRI. Iodine uptake in the uterus was diagnosed with SPECT/CT and compared with the findings of the MRI. Serum TSH level, administered dose of iodine-131 and number of radioiodine therapies were compared between the 2 groups with and without iodine uptake in the uterus. RESULTS: Twenty (26.3%) of 76 patients showed iodine uptake in the uterine cervix on SPECT/CT. It was difficult to distinguish the uptake in the uterus from that in the urinary bladder or rectum using only planar images. The patients with the uterine uptake were younger than those without (median age, 46.5 vs. 62, P = 0.011). There were no significant differences in serum TSH level, administered dose of iodine-131, or number of radioiodine therapies between the 2 groups. In all instances of the 5 patients who underwent pelvic MRI, iodine uptake in the uteri was located in nabothian cysts. CONCLUSION: Iodine uptake in the uterus is frequently found if pelvic SPECT/CT is performed. Nabothian cysts are a predominant cause of iodine uptake in the uterine cervix.

Diagnostic and prognostic value of pretreatment SUV in 18F-FDG/PET in breast cancer: comparison with apparent diffusion coefficient from diffusion-weighted MR imaging.

UNLABELLED: In oncology, the apparent diffusion coefficient (ADC) measured by diffusion-weighted MR imaging (DWI) and the standardized uptake value (SUV) from (18)F-FDG PET have similar clinical applications. The purpose of this study was to assess the correlation between the ADC and SUV and compare their potential in the diagnosis and prediction of prognosis in breast tumors. METHODS: Seventy-nine female patients (age range, 19-69 y; average, 49.1 y) with 83 pathologically proven breast tumors were recruited. The diagnoses consisted of 70 malignant breast tumors (65 cases of invasive ductal carcinoma, 1 of medullary carcinoma, 1 of mucinous carcinoma, 1 of squamous cell carcinoma, and 2 of micropapillary carcinoma) and 13 benign breast tumors (4 cases of fibroadenoma, 4 of mastopathy, 3 of adenosis with atypia, and 2 of benign phyllodes tumor). All patients underwent mammary gland MR imaging with DWI and (18)F-FDG PET within a 2-wk interval. The patients' ADCs and SUVs were measured within the tumor by DWI and (18)F-FDG PET, respectively. For the malignant tumors, we evaluated the relationships among ADC, SUV, histopathologic appearance, and long-term prognosis. RESULTS: A significant difference (P < 0.05) was observed in both parameters (ADC and SUV) between the benign and malignant breast tumors, and the difference was more significant when we introduced a new parameter, SUV/ADC. There was a weak inverse correlation between ADC and SUV (r = -0.36; P = 0.06) among the total tumors; however, this correlation was not significant within the group of malignant tumors. High SUV was found to correlate with larger tumor size, higher nuclear grade, and the triple-negative hormonal receptor profile. High ADC was revealed to be correlated with negative progesterone receptor and positive human epidermal growth factor receptor 2 profile. Higher SUVs also showed a correlation with poor prognosis. No correlation was seen between ADC and prognosis. CONCLUSION: Both SUV and ADC are helpful parameters in differentiating benign from malignant breast tumors. The use of SUV and ADC in combination may help in the diagnosis because of their inverse relationship. High preoperative SUV was associated with poor prognosis, but the contribution of ADC to prognosis prediction was small.

Usefulness of partial volume effect-corrected F-18 FDG PET/CT for predicting I-131 accumulation in the metastatic lymph nodes of patients with thyroid carcinoma.

PURPOSE: The purpose of this study was to evaluate the clinical usefulness of partial volume effect (PVE)-corrected F-18 FDG PET/CT for predicting I-131 accumulation in metastatic lymph nodes (mLNs) during I-131 therapy for papillary thyroid carcinoma (PTC). METHODS: Sixty-five mLNs in 31 PTC patients who underwent F-18 FDG PET/CT in an initial radioiodine therapy (RIT) were retrospectively evaluated. Of these, 25 mLNs were I-131-positive and 40 were I-131-negative. SUVmax and SUVmax with PVE correction (cSUVmax) were measured for each mLN, where PVE correction was performed utilizing a simple table lookup correction method. Then, SUVmax/cSUVmax was compared between I-131-positive and I-131-negative mLNs, including the analyses for the mLNs with small-sized (<1 cm) and weak FDG accumulation (SUVmax <3.5). The predictability for I-131 accumulation with SUVmax/cSUVmax was also compared. RESULTS: For all 65 mLNs, SUVmax/cSUVmax was significantly higher in I-131-negative than I-131-positive mLNs (p < 0.0001). Only in cSUVmax, I-131-negative mLNs were significantly higher than I-131-positive, in terms of the 30 small-sized mLNs (p = 0.0001) and 14 mLNs with weak FDG uptake (p = 0.007). The highest accuracy in predictability for I-131 accumulation was significantly better with cSUVmax (92 %) than SUVmax (62 %) (p < 0.0001). CONCLUSION: PVE-corrected F-18 FDG PET/CT is a valuable predictor of I-131 accumulation in mLNs during RIT.

Prediction of outcome with FDG-PET in definitive chemoradiotherapy for esophageal cancer.

The purpose of this study was to assess the efficacy of ¹8F-fluoro-2-deoxy-glucose uptake positron emission tomography (FDG-PET) for the prediction of outcome in definitive chemoradiotherapy (CRT) for esophageal cancer. We enrolled 56 patients with esophageal cancer treated with definitive CRT and examined by FDG-PET before treatment. We examined the correlation of the maximum standardized uptake value (SUVmax) in FDG-PET of the primary tumor with overall survival (OS), progression-free survival (PFS), local control (LC) and response of the primary tumor. After definitive CRT, 30 patients had a clinical complete response (CR), making the CR rate 54%. For all 56 patients, the 2-year OS rate, PFS rate and LC rates were 64%, 38% and 51%, respectively. We divided the patients into two groups according to SUVmax: SUVmax < 10 (low-SUV) and ≥10 (high-SUV). The 2-year OS rates in the low- and high-SUV groups were 100% and 41%, the PFS rates were 73% and 19%, the LC rates were 71% and 39%, and the CR rates were 100% and 32%, respectively. A univariate analysis revealed significant differences between the low- and high-SUV group in OS, PFS, LC and response (P = 0.0005, 0.0002, 0.048, and <0.0001, respectively). SUVmax and T stage were significantly associated with OS, PFS, LC and response. A multivariate analysis showed significant differences between the SUVmax <10 and ≥10 groups in overall survival and response (P < 0.05). Our result suggests that the SUVmax in FDG-PET of the primary tumor before treatment may have prognostic value for esophageal cancer.