Distinguishing Axillary Lymphadenopathy after COVID-19 Vaccination from Malignant Lymphadenopathy.

Objectives: To study the differences between malignant hypermetabolic axillary lymphadenopathy (MHL) and COVID-19 vaccine-associated axillary hypermetabolic lymphadenopathy (VAHL) using clinical imaging. Methods: A total of 1096 patients underwent Positron Emission Tomography-Computed Tomography (PET-CT) between 1 June 2021 and 30 April 2022 at Ehime University Hospital. In total, 188 patients with axillary lymphadenopathy after the COVID-19 vaccination were evaluated. The patients were classified into three groups such as VAHL (n = 27), MHL (n = 21), and equivocal hypermetabolic axillary lymphadenopathy (EqHL; n = 140). Differences in lymph node (LN) swellings were statistically analyzed using clinical imaging (echography, CT, and 18F-FDG PET). Results: MHL included a higher female population (90.5%) owing to a higher frequency of breast cancer (80.9%). Axillary LNs of MHL did not show any LN fatty hilums (0%); however, those of VAHL and EqHL did (15.8 and 36%, respectively). After the logistic regression analysis of the patients who had axillary lymphadenopathy without any LN fatty hilums, the minor axis length and ellipticity (minor axis/major axis) in the largest axillary LN, SUVmax, and Tissue-to-Background Ratio (TBR) were useful in distinguishing malignant lymphadenopathies. A receiver-operating characteristic (ROC) analysis indicated that a cut-off value of ≥7.3 mm for the axillary LN minor axis (sensitivity: 0.714, specificity: 0.684) and of ≥0.671 for ellipticity (0.667 and 0.773, respectively) in the largest LN with the highest SUVmax and TBR were predictive of MHL. Conclusions: Axillary lymphadenopathy of the minor axis and ellipticity in LN without fatty hilums may be useful to be suspicious for malignancy, even in patients who have received COVID-19 vaccination. Further examinations, such as 18F-FDG PET, are recommended for such patients.

Impact of digital positron emission tomography/computed tomography on the delineation of clinical target volume in advanced lung cancer.

The present study investigated the differences between digital [18F]-Fluorodeoxyglucose (FDG) positron emission tomography [PET]/computed tomography [CT] (dPET/CT) and conventional PET/CT (cPET/CT) in delineating the clinical target volume (CTV) in patients with advanced lung cancer in the involved field radiation therapy (IFRT) era. Patients with advanced lung cancer were scanned using two dual-imaging protocols (dPET/CT and cPET/CT). Two virtual delineations contoured with reference to dPET/CT and cPET/CT images were created for each patient by five radiation oncologists. Changes in the delineation of target volumes in each patient were examined. A total of 10 patients [male/female, 9/1; median age, 65 years (range, 58-80 years)] were enrolled between April 2020 and September 2020. Significant changes in the delineation of CTVs were uncommon between dPET/CT and cPET/CT. A notable increase in CTVn was observed in 10% of the patients (1/10; P<0.05; Smirnov-Grubbs analysis). In this patient, a node that was not assessed as lymph node metastasis when cPET/CT was used was assessed as lymph node metastasis when dPET/CT was used and was included in the CTVn by all five radiation oncologists. In patients with advanced lung cancer, notable changes in CTV delineations are uncommon, regardless of whether dPET/CT or cPET/CT is used. However, in some cases, CTVn delineation with reference to dPET/CT may improve the treatment outcomes of IFRT for advanced lung cancer.

Multicenter Evaluation of the Feasibility of Clinical Implementation of SPECT Myocardial Blood Flow Measurement: Intersite Variability and Imaging Time.

BACKGROUND: Single-center studies have shown that single photon emission computed tomography myocardial blood flow (MBF) measurement is accurate compared with MBF measured with microspheres in a porcine model, positron emission tomography, and angiography. Clinical implementation requires consistency across multiple sites. The study goal is to determine the intersite processing repeatability of single photon emission computed tomography MBF and the additional camera time required. METHODS: Five sites (Canada, Italy, Japan, Germany, and Singapore) each acquired 25 to 35 MBF studies at rest and with pharmacological stress using technetium-99m-tetrofosmin on a pinhole-collimated cadmium-zinc-telluride-based cardiac single photon emission computed tomography camera with standardized list-mode imaging and processing protocols. Patients had intermediate to high pretest probability of coronary artery disease. MBF was measured locally and at a core laboratory using commercially available software. The time a room was occupied for an MBF study was compared with that for a standard rest/stress myocardial perfusion study. RESULTS: With motion correction, the overall correlation in MBF between core laboratory and local site was 0.93 (range, 0.87-0.97) at rest, 0.90 (range, 0.84-0.96) at stress, and 0.84 (range, 0.70-0.92) for myocardial flow reserve. The local-to-core difference in global MBF (bias-MBF) was 5.4% (-3.8% to 14.8%; median [interquartile range]) at rest and 5.4% (-6.2% to 19.4%) at stress. Between the 5 sites, bias-MBF ranged from -1.6% to 11.0% at rest and from -1.9% to 16.3% at stress; the interquartile range in bias-MBF was between 9.3% (4.8%-14.0%) and 22.3% (-10.3% to 12.0%) at rest and between 17.0% (-11.3% to 5.6%) and 33.3% (-10.4% to 22.9%) at stress and was not significantly different between most sites. Both bias and interquartile range were like previously reported interobserver variability and less than the SD of the test-retest difference of 30%. The overall difference in myocardial flow reserve was 1.52% (-10.6% to 11.3%). There were no significant differences between with and without motion correction. The average additional acquisition time varied between sites from 44 to 79 minutes. CONCLUSIONS: The average bias-MBF and bias-MFR values were small with standard deviations substantially less than the test-retest variability. This demonstrates that MBF can be measured consistently across multiple sites and further supports that this technique can be reliably implemented. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03427749.

Effect of preparation method for radioactive iodine therapy on serum electrolytes.

PURPOSE: Thyroid hormone withdrawal (THW) in preparation for radioactive iodine therapy (RIT) may lead to hyponatremia and hyperkalemia because hypothyroidism reduces the glomerular filtration rate. Using recombinant human thyrotropin (rhTSH) may avoid these changes; however, these two preparation methods have not been compared in the literature. The purpose of this study was to reveal whether THW and rhTSH as preparation methods for RIT affect serum electrolytes differently. We also evaluated clinical factors influencing the onset of hyponatremia and hyperkalemia during RIT. MATERIALS AND METHODS: From April 2005 to December 2020, we analyzed 278 patients with thyroid cancer who received RIT. The patients were classified into two groups based on the preparation method, and renal function and serum electrolytes were compared between the groups. We also evaluated clinical factors that may affect overt hyponatremia (serum sodium level < 134 mmol/L) and hyperkalemia (serum potassium level ≥ 5.0 mmol/L). RESULTS: Serum sodium and chloride levels in the THW group were significantly lower than those in the rhTSH group (p < 0.001 and p = 0.002, respectively). In contrast, the serum potassium level in the THW group was significantly higher than that in the rhTSH group (p = 0.008). As for clinical factors that may influence hyponatremia, age and estimated glomerular filtration rate (eGFR) were significantly associated with serum sodium level in the univariate analysis (p = 0.033 and p = 0.006, respectively). In the multivariate analysis, only age was significantly associated with serum sodium level (p = 0.030). Regarding hyperkalemia, distant metastases, the preparation method and eGFR were significantly associated with the serum potassium level in the univariate analysis (p = 0.005, p = 0.005 and p = 0.001, respectively). In the multivariate analysis, only eGFR was significantly associated with hyperkalemia (p = 0.019). CONCLUSION: THW and rhTSH affect serum sodium and potassium levels differently. Renal function may be risk factors for hyperkalemia, whereas older age may be a risk factor for hyponatremia.

Clinical features and prognosis of isolated cardiac sarcoidosis diagnosed using new guidelines with dedicated FDG PET/CT.

BACKGROUND: Diagnostic guidelines for isolated cardiac sarcoidosis (iCS) were first proposed in 2016, but there are few reports on the imaging and prognosis of iCS. This study aimed to evaluate the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging in predicting iCS prognosis. METHODS AND RESULTS: We retrospectively reviewed the clinical and imaging data of 306 consecutive patients with suspected CS who underwent FDG PET/CT with a dedicated preparation protocol and included 82 patients (55 with systemic sarcoidosis including cardiac involvement [sCS], 27 with iCS) in the study. We compared the FDG PET/CT findings between the two groups. We examined the relationship between the CS type and the rate of adverse cardiac events. The iCS group had a significantly lower target-to-background ratio than the sCS group (P = 0.0010). The event-free survival rate was significantly lower in the iCS group than the sCS group (log-rank test, P < 0.0001). iCS was identified as an independent prognostic factor for adverse events (hazard ratio 3.82, P = 0.0059). CONCLUSION: iCS was an independent prognostic factor for adverse cardiac events in patients with CS. The clinical diagnosis of iCS based on FDG PET/CT and new guidelines may be important.

The tumor-to-liver ratio of the standardized uptake value is a useful FDG-PET/CT parameter for predicting malignant intraductal papillary mucinous neoplasm of the pancreas.

Background: The present study aimed to investigate the efficacy of positron emission tomography with 18Fluoro-deoxyglucose (FDG-PET/CT) for predicting malignant intraductal papillary mucinous neoplasm (IPMN). Methods: The records of 88 patients pathologically diagnosed with IPMN after surgery at Ehime University Hospital and Ehime Prefectural Central Hospital from April 2009 to December 2020 were retrospectively reviewed. The patients' characteristics, blood chemistry, and imaging examinations were evaluated as potential predictors of malignant IPMN. Of the PET/CT results, the maximum standardized uptake value (SUVmax) of the tumor, the tumor-to-blood pool ratio of the SUV (TBR), and the tumor-to-liver ratio of the SUV (TLR) were compared. Results: On pathology, the diagnosis was adenoma (IPMA) in 40 patients, high-grade dysplasia (HGD) in 26 patients, and carcinoma (IPMC) in 22 patients. HGD and IPMC were defined as malignant IPMN. On multivariate analyses, TLR ≥ 1.3 and high-risk stigmata were independent predictors of malignant IPMN (P = .001 and P = .007, respectively). When both HRS and TLR ≥ 1.3 were present, the positive predictive value for malignancy was 88.2%. Furthermore, TLR was significantly higher for patients with IPMC than with HGD (P = .039). Conclusion: TLR can be a useful predictor for differentiating benign from malignant IPMN and may be associated with postoperative outcomes.

Quantitative Assessment Using the Compartment Model for Detecting Regional Coronary Artery Disease by Dynamic Myocardial Perfusion Single-Photon Emission Computed Tomography.

BACKGROUND: This study aimed to quantitatively evaluate myocardial perfusion single-photon emission computed tomography (SPECT) using an original analysis tool in the compartment model for detecting regional significant coronary artery disease (CAD).Methods and Results: This study analyzed 41 patients (median age, 76 years) with suspected or known CAD who underwent both dynamic SPECT using 99 mTc-tetrofosmin and invasive coronary angiography. The quantitative analysis was performed using a single-tissue compartment model to evaluate the diagnostic performance of the myocardial flow reserve (MFR) for regional significant CAD, excluding infarcted territories. In the regional analysis, 114 vessels were assessed, of which 31 were diagnosed as significant coronary lesions (≥70% stenosis and/or fraction flow reserve ≤0.8). The MFR of regional significant CAD was significantly lower than that of non-significant CAD (1.11 [0.97-1.31] vs. 1.74 [1.30-2.27]; P<0.001). In the receiver operating characteristic curve analysis, the MFR displayed an area under the curve (AUC) of 0.81. While analyzing each coronary artery territory, the diagnostic performance of the MFR value in the left anterior descending (LAD) artery territory was found to be significantly higher than that found in qualitative assessment (AUC: 0.84 vs. 0.61). CONCLUSIONS: A quantitative analysis of dynamic SPECT data facilitated detecting regional CAD. For the LAD artery, the MFR displayed a higher diagnostic performance than the qualitative assessment of conventional myocardial perfusion SPECT.

Usefulness of albumin-globulin ratio as a clinical prognostic factor in patients with thyroid cancer treated with radioiodine.

OBJECTIVE: Albumin-globulin ratio (AGR), which is calculated by dividing serum albumin by serum globulin, is considered as a cancer-related inflammation biomarker. Although the prognosis of many solid cancers has been shown to be associated with AGR, there are no studies to demonstrate the association between the prognosis of thyroid cancer and AGR. The purpose of this study is to reveal the relationship between AGR and overall survival (OS) in patients with thyroid cancer who received radioactive iodine therapy (RIT). METHODS: Eighty-eight patients with thyroid cancer who had received RIT for the first time in our institution were included. The values before RIT were adopted as initial measurements for serum albumin, globulin, and thyroglobulin (Tg) and used for analysis. Patients were divided into two groups based on the AGR value. We analyzed the relationship between clinical factors and treatment outcome. RESULTS: The median follow-up period was 92.4 months (range: 30.1-173.9 months). The 5-year OS and progression-free survival (PFS) were 94% and 54%, respectively. Seventeen patients (< 65 years, 8; and ≥ 65 years, 9) died during the follow-up period. Low AGR was significantly associated with OS in both univariate and multivariate analyses (p = 0.0059 and p = 0.0120, respectively). As the 5-year OS was as high as 94%, there was no significant difference in survival rate between the two groups during the first 5 years. However, there seemed to be a remarkable difference in 10 years after the first RIT. On the other hand, Tg was significantly associated with PFS in both univariate and multivariate analyses (p = 0.0016 and p = 0.0441, respectively). In patients under the age of 65, the PFS rate was significantly lower in the low AGR group (p < 0.0001), while there was no difference in PFS rate between the two AGR groups in patients aged 65 years or older. CONCLUSIONS: AGR may be used as a prognostic factor in relatively younger patients with thyroid cancer treated with radioiodine, while it may be less useful in the older. Overall, it may be an independent prognostic factor for long-term survival in those with thyroid cancer.

Clinical significance of corrected relative flow reserve derived from 13N-ammonia positron emission tomography combined with coronary computed tomography angiography.

BACKGROUND: This study evaluated corrected relative flow reserve (RFR) derived from 13N-ammonia positron emission tomography (PET) combined with coronary computed tomography angiography (CTA). METHODS: We analyzed 61 patients who underwent coronary CTA, 13N-ammonia PET, and invasive coronary angiography. Triple-vessel disease were excluded. Conventional RFRs were calculated as the ratio of hyperemic myocardial blood flow (hMBF) of hypoperfusion areas to those of non-ischemic lesions. Corrected RFRs were calculated using PET and coronary CTA to adjust coronary territories to their feeding vessels. Diagnostic performance was compared to detect obstructive coronary lesions. RESULTS: Of the 180 vessels analyzed, 50 were diagnosed as obstructive lesions (≥ 70% stenosis and/or fractional flow reserve value ≤ 0.8). The coronary flow reserve (CFR), hMBF, conventional RFR, and corrected RFR of obstructive lesions were significantly lower than those of non-obstructive lesions. In receiver operating characteristic curve analysis, these quantitative PET measurements had area under the curve of 0.67, 0.71, 0.89, and 0.92, respectively. Diagnostic performance differences between corrected and conventional RFR were not statistically significant. CONCLUSION: In patients with single or double vessel disease, indices of RFR, with or without coronary angiographic guidance of the reference coronary territory, are better discriminators of flow-limiting stenoses than hMBF and CFR.

The prognostic significance of whole-body and spleen MTV (metabolic tumor volume) scanning for patients with diffuse large B cell lymphoma.

BACKGROUND: Positron Emission Tomography-Computed Tomography (PET-CT) has been changing diagnostic and therapeutic strategies for patients with cancers, and several PET-CT-related prognostic factors have been reported. We have focused on metabolic tumor volumes (MTVs) over the whole body and in specific organs using 18F-PET-CT imaging, and have compared clinical data to know the prognosis of patients with diffuse large B cell lymphoma (DLBCL). PATIENTS AND METHODS: From January 2006 to December 2016, patients who were newly diagnosed for de novo DLBCL and who received 18F-FDG PET-CT scans for disease staging at Ehime University Hospital were reviewed. RESULTS: A total of forty out of 108 patients with DLBCL were analyzed. The median and the average follow-up were 3.9 years and 3.6 years. Both MTV50 and MTV60 whole-body searching indicated effective prognostic values for patients with DLBCL statistically (P = 0.027). However, analysis of MTVs in the spleen and in bone marrow did not provide any prognostic value. Receiver operating characteristic (ROC) analysis indicated that the cutoff level 25.8 in MTV60 is the most effective prognostic value (P = 0.022) which predicts patient survival after treatment with R-CHOP chemotherapy. CONCLUSION: MTV60 using whole-body scanning appears to be an effective indicator in DLBCL and indicates the patient prognosis.

Bilateral parkinsonism in a patient with infarcts involving the unilateral basal ganglia.

We describe a 61-year-old woman with bilateral parkinsonism caused by unilateral infarction limited to the territory of the lenticulostriate arteries. Although dopamine transporter imaging with single-photon emission computed tomography (DaTSPECT) demonstrated reduced putaminal tracer binding concordant with the size and location of the vascular lesion, the specific binding ratio was within the normal range. Five months after onset, the patient was free from parkinsonism without the use of any antiparkinsonian agents. When patients show bilateral parkinsonism, it is important to consider infarction of the lenticulostriate arteries. Additionally, DaTSPECT might be useful for predicting the prognosis of parkinsonism caused by infarction.

Features and clinical impact of extra-cardiac lesions with 18F-fluorodeoxyglucose positron emission tomography in patients with suspected cardiac sarcoidosis.

BACKGROUND: Sarcoidosis is a systemic inflammatory disorder and can often affect any other organs beyond the heart. Whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is used to detect not only cardiac but also extra-cardiac involvement of sarcoidosis. However, the features and clinical impact of extra-cardiac lesions have not yet been fully elucidated. Therefore, this study aimed to clarify these using FDG-PET. METHODS AND RESULTS: We enrolled 120 consecutive patients with abnormal findings clinically suggesting cardiac sarcoidosis who underwent whole-body FDG-PET. In this study, a patient with suspected cardiac sarcoidosis was defined as one having both clinically suspected findings and FDG-PET positive cardiac uptake. Subsequently, a total of 36 patients with suspected cardiac sarcoidosis were found and analyzed. Extra-cardiac involvement was detected in 35 lesions of 14 patients (39% per patient). In particular, the extra-cardiac lesions were widely distributed throughout the body, and mediastinal/hilar lymph node involvement was most commonly observed. In most of the patients (93% per patient, 13/14), the extra-cardiac lesions were localized in the regions that were considered more accessible with less risk of complication compared with endomyocardial biopsy (EMB). Based on the FDG-PET findings, 8 patients underwent extra-cardiac biopsy without complication, and its diagnostic sensitivity for histological sarcoidosis was high (75%, 6/8). Moreover, FDG-PET-guided extra-cardiac biopsy could confirm histological sarcoidosis in 4 lesions that EMB failed to prove. CONCLUSIONS: Extra-cardiac involvement in patients with suspected cardiac sarcoidosis was relatively high. FDG-PET-guided extra-cardiac biopsy may be safe and useful for the imaging based diagnosis of cardiac sarcoidosis.

Treatment intensity and control rates in combining external-beam radiotherapy and radioactive iodine therapy for metastatic or recurrent differentiated thyroid cancer.

BACKGROUND: To evaluate the treatment outcomes of external-beam radiotherapy (EBRT) with or without radioactive iodine therapy (RAIT) for metastatic or recurrent lesions of differentiated thyroid cancer (DTC). METHODS: Between August 1997 and March 2018, 73 lesions (distant metastases, 50; regional lymph-node metastases, 17; postoperative tumor-bed recurrences, 6) in 36 patients that had received EBRT with or without RAIT were reviewed. Doses of EBRT were 8-70 Gy (median 40 Gy). Seventeen patients received RAIT after EBRT. RESULTS: Median follow-up time of imaging studies was 14 months (range 1-110 months). Two-year overall survival rates and control rates of EBRT sites were 71% and 62%, respectively. Two-year control rates for EBRT of < 30 Gy (n = 7), 30 Gy (n = 13), 31-49 Gy (n = 25), 50 Gy (n = 20), and > 50 Gy (n = 8) were 0%, 56%, 53%, 79%, and 100%, respectively. There were statistically significant differences in control rates between < 30 Gy and 30 Gy (p = 0.003), and between 50 Gy and > 50 Gy (p = 0.037). Control rates of > 50 Gy were significantly better compared to ≤ 50 Gy (p = 0.021). Two-year control rates with (n = 28) and without (n = 45) post-EBRT RAIT were 89% and 45%, respectively (p = 0.009). In multivariate analysis, EBRT of > 50 Gy and post-EBRT RAIT were significant independent factors for favorable control of EBRT sites (hazard ratio [HR], 5.72; 95% confidence interval [CI], 1.21-27.1; p = 0.028 and HR, 2.98; 95% CI, 1.28-6.98; p = 0.012, respectively). CONCLUSION: EBRT of > 50 Gy and post-EBRT RAIT appeared to be useful for long-term control of EBRT sites for metastatic or recurrent lesions of DTC.

Impact of the sampling rate of dynamic myocardial computed tomography perfusion on the quantitative assessment of myocardial blood flow.

BACKGROUND: The relationship between shot-to-shot sampling rates for dynamic myocardial computed tomography perfusion (CTP) and robustness of CTP-derived myocardial blood flow (CT-MBF) is debatable. We retrospectively investigated the influence of a reduced sampling rate for dynamic CTP on CT-MBF computation and diagnostic performance for detecting myocardial perfusion abnormalities. METHODS: Pharmacological stress dynamic whole-heart CTP was performed in 120 patients suspected with coronary artery disease. Dynamic CTP data were obtained for 30 continuous heartbeats during the R-peak to R-peak (1RR) interval on electrocardiography. Three additional datasets were created with sub-sampling acquisitions every 2, 3, and 4 heartbeats from the original dataset as interval times of 2RR, 3RR, and 4RR, respectively. CT-MBF was calculated using deconvolution analysis and determined as the mean value of the whole heart (global CT-MBF) and using the 16-segment model (segmental CT-MBF). The diagnostic performance of segmental CT-MBF for detecting perfusion abnormalities was compared to that of cardiac magnetic resonance imaging as the gold standard in 32 of 120 patients. These results were compared among the four CTP datasets. RESULTS: Global CT-MBFs for 1RR, 2RR, 3RR, and 4RR sampling were 1.57 ±â€¯0.34, 1.54 ±â€¯0.36, 1.51 ±â€¯0.37, and 1.41 ±â€¯0.33 mL/g/min, respectively. Areas under the receiver operating characteristic curves of segmental CT-MBF for 1RR, 2RR, 3RR, and 4RR sampling were 0.84, 0.83, 0.79, and 0.76, respectively (1RR versus [vs.] 2RR, non-significant; 1RR vs. 3RR or 4RR, p < 0.05). CONCLUSION: CT-MBF with 2RR sampling has similar performance with regard to quantification and detecting myocardial perfusion abnormalities as that with 1RR sampling.

Incremental diagnostic value of whole-heart dynamic computed tomography perfusion imaging for detecting obstructive coronary artery disease.

BACKGROUND: This study aimed to evaluate the incremental diagnostic value of dynamic myocardial computed tomography (CT) perfusion (CTP) imaging for detecting obstructive coronary artery disease (CAD) in comparison with coronary CT angiography (CTA). METHODS: Thirty-eight patients who had undergone coronary CTA and pharmacological stress dynamic CTP before invasive coronary angiography (ICA) were selected retrospectively. Using ICA, obstructive CAD was defined as the presence of severe (≥70%) or moderate (50-69%) stenosis with fractional flow reserve (FFR) <0.75. For CT evaluations, coronary vessels with any stenosis ≥50%, ≥70% or unassessable lesions were considered significantly stenotic. Dynamic CTP was assessed quantitatively using CT-derived myocardial blood flow (CT-MBF). Receiver operating characteristic (ROC) curve analysis determined the cut-off value of CT-MBF for identifying obstructive CAD. The diagnostic performances of CTA alone and integrated CTA and CTP assessments for detecting obstructive CAD were compared. RESULTS: Using ICA and FFR, 24 of 114 vessels had obstructive CAD. The cut-off value of CT-MBF for detecting obstructive CAD was 1.26mL/g/min. The sensitivity, specificity, and positive and negative predictive values (PPV and NPV) at the vessel level were 96%, 57%, 37%, and 98% for CTA, and 83%, 93%, 77%, and 95% for integrated CTA and CTP assessment using cut-off 50% stenosis on CTA, respectively. The sensitivity, specificity, and PPV and NPV at the vessel level were 79%, 69%, 40%, and 93% for CTA, and 71%, 97%, 85%, and 93% for integrated CTA and CTP assessment using cut-off 70% stenosis on CTA, respectively. The area under the ROC curve for CTA and CTP was significantly higher than that for CTA alone (0.96 vs. 0.84, p<0.05). CONCLUSIONS: Stress dynamic myocardial CTP is feasible to detect hemodynamically obstructive CAD in patients with high pre-test likelihood and helps for improving diagnostic performance in comparison with coronary CTA alone.

Positron emission tomography/computed tomography detection of increased 18F-fluorodeoxyglucose uptake in the cardiac atria of patients with atrial fibrillation.

BACKGROUND: Direct evidence of inflammatory activity in the atria of patients with atrial fibrillation (AF) is scarce. We assessed the capability of positron-emission tomography/computed tomography (PET/CT) to diagnose AF based on fluorodeoxyglucose (FDG) uptake in the atrial wall. METHODS AND RESULTS: Among 8233 patients who underwent FDG-PET/CT as work-up for malignancies, we identified 180 consecutive patients with AF (2.2%). Of those, we selected 137 patients who had fasted >12 h before FDG injection for inclusion in the experimental group (88 men and 49 women; age: 72.7 ±â€¯8.9 years). Controls were 62 age- and sex-matched patients without AF. For visual analysis, we used a 4-point grading system. For quantitative analysis, we used the maximum standard uptake value (SUVmax) in the left (LA) and right atrial (RA) myocardium and the target-to-background ratio (TBR) of SUVmax to blood pool activity. The sensitivity, specificity, and positive-predictive value for detecting AF visually were 54.0%, 95.2%, and 96.1%, respectively; for quantitative analysis, the respective values were 65.7%, 75.8%, and 85.7%. Multivariable analysis of 11 clinical and imaging variables showed significant associations with RA SUVmax (odds ratio [OR]: 14.353, P = 0.026) and LA volume (OR: 1.371, P = 0.0001). The RA TBR was greater in cases with persistent AF than in those with paroxysmal AF (P < 0.0001). Pathological investigation of 4 autopsy hearts confirmed infiltration of extravascular macrophages and lymphocytes in the regions with FDG uptake. CONCLUSIONS: Higher atrial FDG uptake was associated with AF. PET/CT could be a useful tool for detecting local inflammation in the atria with AF.

New classification of hydronephrosis on 18F-FDG-PET/CT predicts post-operative renal function and muscle-invasive disease in patients with upper urinary tract urothelial carcinoma.

OBJECTIVES: To evaluate the value of a classification of hydronephrosis on 18F-flurodeoxyglucose (FDG)-PET/CT in predicting post-operative renal function and pathological outcomes among patients with upper urinary tract urothelial carcinoma. METHODS: We retrospectively reviewed 71 patients treated with nephroureterectomy (NU) for upper urinary tract urothelial carcinoma after FDG-PET/CT between 2010 and 2016. Eight patients treated with ureteral stent or nephrostomy at the time of FDG-PET/CT were excluded. We classified hydronephrosis based on renal excretion of FDG as follows: Type 0, no hydronephrosis; Type 1, hydronephrosis with FDG excretion; and Type 2, hydronephrosis without FDG excretion. eGFR was recorded before pre-operataive FDG-PET/CT examination and after nephroureterectomy. RESULTS: Thirty-three patients (52%) had hydronephrosis, classified as Type 1 in 19 patients (30%) and Type 2 in 14 (22%). Type 2 hydronephrosis was associated with ureteral cancer and severe hydronephrosis on CT. Median changes in eGFR before and after nephroureterectomy in patients classified as Type 0, 1 and 2 were -23.9, -18.8 and 2.0 ml/min/1.73 m2, respectively. On multivariate analysis, Type 2 hydronephrosis was a significant predictor of change in eGFR (P = 0.001). Rates of muscle-invasive upper urinary tract urothelial carcinoma among Type 0, 1 and 2 patients were 37, 42 and 86%, respectively. On multivariate analysis, Type 2 hydronephrosis was a significant predictor of muscle-invasive upper urinary tract urothelial carcinoma (P = 0.032, OR 6.491). CONCLUSIONS: This classification of hydronephrosis from FDG-PET/CT is simple and useful for predicting post-operative renal function and muscle-invasive disease in patients with upper urinary tract urothelial carcinoma, especially with ureteral cancer. This classification can help in deciding eligibility for lymphadenectomy or perioperative cisplatin-based chemotherapy.

Parotid Oncocytoma as a Manifestation of Birt-Hogg-Dubé Syndrome.

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disease characterized by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothoraces, and renal cancers. Oncocytomas are benign epithelial tumors that are also rare. Recently, there have been a few case reports of BHD with a parotid oncocytoma that appears to have a BHD phenotype. Here we document the eighth known case and describe the magnetic resonance imaging features of the parotid oncocytoma, which mimicked Warthin's tumor. Radiologists should be aware of the association between these rare disorders.

Clinical Usefulness of Coronary Flow Reserve Ratio for the Detection of Significant Coronary Artery Disease on 13N-Ammonia Positron Emission Tomography.

BACKGROUND: This study aimed to evaluate the diagnostic performance of coronary flow reserve (CFR), hyperemic myocardial blood flow (hMBF), and CFR ratio for detecting significant coronary artery disease (CAD) on 13N-ammonia positron emission tomography (PET).Methods and Results:We analyzed 63 patients (mean age, 71±9 years; 43 males) with suspected CAD who underwent both pharmacological stress/rest 13N-ammonia PET and coronary angiography. CFR and hMBF for PET were calculated automatically using quantitative PET software, and the CFR ratio was defined as the ratio of per-vessel CFR to maximum CFR in a standard 17-segment model. We compared the diagnostic performance among the 3 quantitative values. In the per-vessel analysis, 55 vessels were diagnosed as significant CAD (≥70% stenosis and/or fraction flow reserve ≤0.8). CFR, hMBF, and CFR ratio of significant CAD were significantly lower than for non-significant CAD (1.85±0.69 vs. 2.38±0.69; P<0.01, 1.67±0.54 vs. 2.19±0.52 mL·min-1·g-1; P<0.01, and 0.66±0.15 vs. 0.82±0.09; P<0.01, respectively). In the receiver-operating characteristic curve analysis, CFR, hMBF, and CFR ratio had areas under the curve of 0.71, 0.75, and 0.85 respectively, and the CFR ratio was significantly higher than CFR and hMBF (P<0.05). The sensitivity, specificity, and accuracy of the CFR ratio with an optimal cutoff value of 0.75 were 75%, 85%, and 82%, respectively. CONCLUSIONS: Clinically, the CFR ratio in 13N-ammonia PET was more effective in detecting significant CAD.