Predictive value of SUVmax from initial 18F-FDG PET/CT scans for treatment outcomes in endometrial cancer patients undergoing fertility sparing management.

OBJECTIVE: To evaluate whether the maximum standardized uptake value (SUVmax) from initial 18F-FDG PET/CT (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography) scans could be a predictor of complete response and recurrence in patients with endometrial cancer who are undergoing fertility sparing management. METHODS: We conducted a retrospective review of patients who were diagnosed with endometrial cancer through biopsy and chose to undergo fertility sparing management using progestin at the Asan Medical Center, from January 2011 to December 2020. Of these, 113 patients who had an 18-FDG-PET/CT scan before starting treatment were included in our study. We measured SUVmax and examined its correlation with complete response and time to progression after achieving complete response to progestin therapy. RESULTS: Of 113 patients, 73 (64.6%) achieved a complete response through fertility sparing management. The receiver operating characteristic curve analysis revealed that the optimal cut-off value of SUVmax for predicting complete response was 6.2 (sensitivity 79.5%, specificity 57.5%, p=0.006). After analyzing recurrence in the 73 patients who achieved complete response, we found that patients with an SUVmax value >6.2 had a significantly shorter time to progression compared with those with a value <6.2. (p=0.04). CONCLUSIONS: SUVmax values of PET-CT, along with other clinicopathological parameters, could be used to predict treatment response and recurrence risk in patients with stage I endometrial cancer undergoing fertility sparing management.

Diagnostic performance of a deep-learning model using 18F-FDG PET/CT for evaluating recurrence after radiation therapy in patients with lung cancer.

OBJECTIVE: We developed a deep learning model for distinguishing radiation therapy (RT)-related changes and tumour recurrence in patients with lung cancer who underwent RT, and evaluated its performance. METHODS: We retrospectively recruited 308 patients with lung cancer with RT-related changes observed on 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) performed after RT. Patients were labelled as positive or negative for tumour recurrence through histologic diagnosis or clinical follow-up after 18F-FDG PET/CT. A two-dimensional (2D) slice-based convolutional neural network (CNN) model was created with a total of 3329 slices as input, and performance was evaluated with five independent test sets. RESULTS: For the five independent test sets, the area under the curve (AUC) of the receiver operating characteristic curve, sensitivity, and specificity were in the range of 0.98-0.99, 95-98%, and 87-95%, respectively. The region determined by the model was confirmed as an actual recurred tumour through the explainable artificial intelligence (AI) using gradient-weighted class activation mapping (Grad-CAM). CONCLUSION: The 2D slice-based CNN model using 18F-FDG PET imaging was able to distinguish well between RT-related changes and tumour recurrence in patients with lung cancer.

Performance of deep learning models for response evaluation on whole-body bone scans in prostate cancer.

OBJECTIVE: We aimed to develop deep learning classifiers for assessing therapeutic response on bone scans of patients with prostate cancer. METHODS: A set of 3791 consecutive bone scans coupled with their last previous scan (1528 patients) was evaluated. Bone scans were labeled as "progression" or "nonprogression" on the basis of clinical reports and image review. A 2D-convolutional neural network architecture was trained with three different preprocessing methods: 1) no preprocessing (Raw), 2) spatial normalization (SN), and 3) spatial and count normalization (SCN). Data were allocated into training, validation, and test sets in the ratio of 72:8:20, with the 20% independent test set rotating all scans over a five-fold testing procedure. A Grad-CAM algorithm was employed to generate class activation maps to visualize the lesions contributing to the decision. Diagnostic performance was compared using area under the receiver operating characteristics curves (AUCs). RESULTS: The data consisted of 791 scans labeled as "progression" and 3000 scans labeled as "nonprogression." The AUCs of the classifiers were 0.632-0.710 on the Raw dataset, were significantly higher with the use of SN at 0.784-0.854 (p < 0.001 for Raw versus SN), and higher still with SCN at 0.954-0.979 (p < 0.001 for SN versus SCN). Class activation maps of the SCN model visualized lesions contributing to the model's decision of progression. CONCLUSION: With preprocessing of spatial and count normalization, our deep learning model achieved excellent performance in classifying the therapeutic response of bone scans in patients with prostate cancer.

Application of preoperative fluorodeoxyglucose-PET/CT parameters for predicting prognosis of high-grade neuroendocrine cervical cancer.

OBJECTIVE: High-grade neuroendocrine cervical cancer (HGNECC) is a rare and aggressive cervical cancer subtype. In this study, we aimed to evaluate the prognostic value of fluorodeoxyglucose-PET/computed tomography (CT) parameters for HGNECC. MATERIALS AND METHODS: This single-center retrospective study included 29 patients with HGNECC who underwent fluorodeoxyglucose-PET/CT scan followed by surgery between 2006 and 2016. RESULTS: The median follow-up period was 40 (range, 4-184) months. After surgery, the resection margins were tumor-negative in 28 patients (96.6%), 8 (27.6%) patients had parametrial tumor invasion, and 7 patients (24.1%) tested positive for lymph node metastasis. The tumor recurred in 20 patients (69%) and 18 patients (62.1%) died during the observation period. In the univariate analyses, age and total lesion glycolysis (TLG) were associated with worse disease-free survival (DFS) (age, hazard ratio 1.056, 95% CI 1.014-1.100, P  = 0.009; TLG2.5, hazard ratio 1.003, 95% CI 1-1.006, P  = 0.033; and TLG3.0, hazard ratio 1.003, 95% CI 1-1.006, P  = 0.034). In the multivariate analyses, older age and higher TLG3.0 were identified as independent poor prognostic factors for DFS (age, hazard ratio 1.058, 95% CI 1.014-1.104, P  = 0.009; TLG3.0, hazard ratio 1.004, 95% CI 1-1.007, P  = 0.033), while resection margin involvement was identified as an independent factor to predict poor overall survival (hazard ratio 20.717, 95% CI 1.289-332.964, P  = 0.032). CONCLUSION: Among the preoperative fluorodeoxyglucose-PET/CT parameters, TLG3.0 may be useful for predicting DFS in patients with HGNECC.

53 GBd PAM-4 fully-integrated silicon photonics transmitter with a hybrid flip-chip bonded laser.

We present a fully-integrated single-lane 53 GBd PAM-4 silicon photonics (SiPh) transmitter (Tx) with a flip-chip bonded laser diode (LD). The LD is butt-coupled to a Si edge coupler including a SiO2 suspended spot-size converter. The coupled power exceeds 10 dBm with a 1 dB allowable misalignment of 2.3 µm. The RF and eye performances of the Tx are evaluated. Extinction ratio >5 dB is obtained at 3.5 Vppd voltage swing. Aided by silicon capacitors, the Tx decouples parasitic inductances leading to remarkable improvements in the eye openings and transmitter dispersion eye closure quaternary by 1.16 dB. By implementing the fully-integrated Tx with driver packaging, we successfully demonstrate 106 Gb/s real-time operation satisfying KP4-FEC threshold at -5 dBm receiver sensitivity.

Hyaluronic acid filler injection for deep nasolabial folds: A novel intraoral approach.

Hyaluronic acid filler injection is a minimally invasive procedure for facial rejuvenation that involves injecting filling materials to correct the volume or augment specific areas in the face. Deep nasolabial folds are a common concern in aging people. The simplest way to correct a deep nasolabial fold to rejuvenate the face is to inject Ristow's space with hyaluronic acid fillers. However, conventional injection methods, such as percutaneous injections using a needle, can cause severe complications, such as skin necrosis or blindness due to intravascular injections. Therefore, the aim of the present study was to introduce a safe technique for intraoral filler injections in deep nasolabial folds and review related anatomic features to evaluate the safety of this technique.

A novel needle-free microjet drug injector using Er:YAG LASER: A completely new concept of transdermal drug delivery system.

The skin barrier effectively inhibits the penetration of substances; therefore, drug delivery, especially the delivery of drugs that are hydrophilic, through the skin, is challenging. Objectives: Physicians in the esthetic field now use the transdermal drug delivery system to attempt to deliver esthetic materials, such as hyaluronic acid and poly-DL-lactic acid into the skin. Conventionally, esthetic physicians manually injected these materials using needle syringes into the dermis layer. However, the injection is often irregular, imprecise, slow, and painful. Injector devices have been developed to overcome these limitations. A total of five Korean cadavers (that of three men and two women with a mean age of 69.2 years; range, 60-73 years) underwent laser injection. We used a device called Er:YAG LASER to create the pressure needed for microjet delivery to the skin of the cadaver. Discussion: In this study, the first LASER pressure-based, needle-free microjet injector was used to deliver drugs effectively into the dermis of a cadaver. This study showed that a novel needle-free microjet injector using Er:YAG LASER can introduce beneficial, liquid, esthetic drugs into the papillary dermal layer (depth of 300um) with minimal epidermal damage.

Diagnostic performance of deep learning models for detecting bone metastasis on whole-body bone scan in prostate cancer.

PURPOSE: We evaluated the performance of deep learning classifiers for bone scans of prostate cancer patients. METHODS: A total of 9113 consecutive bone scans (5342 prostate cancer patients) were initially evaluated. Bone scans were labeled as positive/negative for bone metastasis using clinical reports and image review for ground truth diagnosis. Two different 2D convolutional neural network (CNN) architectures were proposed: (1) whole body-based (WB) and (2) tandem architectures integrating whole body and local patches, here named as "global-local unified emphasis" (GLUE). Both models were trained using abundant (72%:8%:20% for training:validation:test sets) and limited training data (10%:40%:50%). The allocation of test sets was rotated across all images: therefore, fivefold and twofold cross-validation test results were available for abundant and limited settings, respectively. RESULTS: A total of 2991 positive and 6142 negative bone scans were used as input. For the abundant training setting, the receiver operating characteristics curves of both the GLUE and WB models indicated excellent diagnostic ability in terms of the area under the curve (GLUE: 0.936-0.955, WB: 0.933-0.957, P > 0.05 in four of the fivefold tests). The overall accuracies of the GLUE and WB models were 0.900 and 0.889, respectively. With the limited training setting, the GLUE models showed significantly higher AUCs than the WB models (0.894-0.908 vs. 0.870-0.877, P < 0.0001). CONCLUSION: Our 2D-CNN models accurately classified bone scans of prostate cancer patients. While both showed excellent performance with the abundant dataset, the GLUE model showed higher performance than the WB model in the limited data setting.

Anatomical consideration of deep calf veins: application to catheter-directed thrombolysis.

PURPOSE: An antegrade approach is frequently used in catheter-directed thrombolysis to remove deep-vein thrombosis. However, the antegrade approach is difficult when accessing veins with small diameters; therefore, understanding the variation of deep calf vein is important. METHODS: This study measured the diameters and surface areas of the proximal and distal posterior tibial vein, peroneal vein, and anterior tibial vein to determine which are preferable for venous access. This study dissected 132 legs from Korean and Thai cadavers. The proximal and distal posterior tibial vein, peroneal vein, and anterior tibial vein were scanned and measured. RESULTS: The mean diameter and surface area were largest for the proximal tibial vein, at 6.34 mm and 0.312 cm2, respectively, followed by the anterior tibial vein (5.22 mm and 0.213 cm2), distal posterior tibial vein (3.29 mm and 0.091 cm2), and peroneal vein (3.43 mm and 0.081 cm2). The proximal posterior tibial vein and anterior tibial vein have large diameters and surface areas, which make them ideal for applying an antegrade approach in catheter-directed thrombolysis. CONCLUSIONS: The distal posterior tibial vein and peroneal vein are not recommended due to their smaller surface areas and also the anatomical variations therein.

Deep learning detection of prostate cancer recurrence with 18F-FACBC (fluciclovine, Axumin®) positron emission tomography.

PURPOSE: To evaluate the performance of deep learning (DL) classifiers in discriminating normal and abnormal 18F-FACBC (fluciclovine, Axumin®) PET scans based on the presence of tumor recurrence and/or metastases in patients with prostate cancer (PC) and biochemical recurrence (BCR). METHODS: A total of 251 consecutive 18F-fluciclovine PET scans were acquired between September 2017 and June 2019 in 233 PC patients with BCR (18 patients had 2 scans). PET images were labeled as normal or abnormal using clinical reports as the ground truth. Convolutional neural network (CNN) models were trained using two different architectures, a 2D-CNN (ResNet-50) using single slices (slice-based approach) and the same 2D-CNN and a 3D-CNN (ResNet-14) using a hundred slices per PET image (case-based approach). Models' performances were evaluated on independent test datasets. RESULTS: For the 2D-CNN slice-based approach, 6800 and 536 slices were used for training and test datasets, respectively. The sensitivity and specificity of this model were 90.7% and 95.1%, and the area under the curve (AUC) of receiver operating characteristic curve was 0.971 (p < 0.001). For the case-based approaches using both 2D-CNN and 3D-CNN architectures, a training dataset of 100 images and a test dataset of 28 images were randomly allocated. The sensitivity, specificity, and AUC to discriminate abnormal images by the 2D-CNN and 3D-CNN case-based approaches were 85.7%, 71.4%, and 0.750 (p = 0.013) and 71.4%, 71.4%, and 0.699 (p = 0.053), respectively. CONCLUSION: DL accurately classifies abnormal 18F-fluciclovine PET images of the pelvis in patients with BCR of PC. A DL classifier using single slice prediction had superior performance over case-based prediction.

Feasibility and effectiveness of treatment strategy of tandem high-dose chemotherapy and autologous stem cell transplantation in combination with 131 I-MIBG therapy for high-risk neuroblastoma.

This study was performed to evaluate the safety and effectiveness of tandem HDCT/ASCT combined with targeted radiotherapy using 131 I-MIBG for high-risk neuroblastoma. Patients with high-risk neuroblastoma were treated with 8 to 10 cycles of induction chemotherapy before tandem HDCT/ASCT. Patients received 131 I-MIBG treatment before the second HDCT/ASCT. Local radiotherapy and maintenance therapy were performed after tandem HDCT/ASCT. Between 2012 and 2016, 19 patients were diagnosed with high-risk neuroblastoma in our institution and 18 of them received tandem HDCT/ASCT combined with 131 I-MIBG therapy. For the first HDCT/ASCT regimen, 12 patients received busulfan/melphalan and six patients received melphalan/etoposide/carboplatin. The second HDCT included ThioCy. The median dose of 131 I-MIBG was 17.2 mCi/kg for the first eight patients, while 12 patients in the latter period of the study received reduced dose of 10.7 mCi/kg. The 5-year OS and EFS rates were 79% and 61%, respectively, for all 19 patients with high-risk neuroblastoma, and 83% and 64%, respectively, for 18 patients who completed tandem HDCT/ASCT combined with 131 I-MIBG therapy. Six patients experienced disease relapse and five patients died. Treatment-related mortality was not observed. Among 15 evaluable patients, 11 patients (73%) developed hypothyroidism, six patients (40%) had CKD, and six patients (40%) had growth failure. Hypothyroidism and growth failure were less frequent in patients who received reduced doses of 131 I-MIBG therapy. Tandem HDCT/ASCT combined with HD 131 I-MIBG therapy could be feasible for patients with high-risk neuroblastoma with acceptable toxicity profiles and favorable outcomes.

Clinicopathologic risk factors of radioactive iodine therapy based on response assessment in patients with differentiated thyroid cancer: a multicenter retrospective cohort study.

PURPOSE: We investigated whether predictive clinicopathologic factors can be affected by different response criteria and how the clinical usefulness of radioactive iodine (RAI) therapy should be evaluated considering variable factors in patients with differentiated thyroid carcinoma (DTC). METHODS: A total of 1563 patients with DTC who underwent first RAI therapy after total or near total thyroidectomy were retrospectively enrolled from 25 hospitals. Response to therapy was evaluated with two different protocols based on combination of biochemical and imaging studies: (1) serum thyroglobulin (Tg) and neck ultrasonography (US) and (2) serum Tg, neck US, and radioiodine scan. The responses to therapy were classified into excellent and non-excellent or acceptable and non-acceptable to minimize the effect of non-specific imaging findings. We investigated which factors were associated with response to therapy depending on the follow-up protocols as well as response classifications. Multivariate logistic regression analysis was performed to identify factors significantly predicting response to therapy. RESULTS: The proportion of patients in the excellent response group significantly decreased from 76.5 to 59.6% when radioiodine scan was added to the follow-up protocol (P < 0.001). Preparation method (recombinant human TSH vs. thyroid hormone withdrawal) was a significant factor for excellent response prediction evaluated with radioiodine scan (OR 2.129; 95% CI 1.687-2.685; P < 0.001) but was not for other types of response classifications. Administered RAI activity, which was classified as low (1.11 GBq) or high (3.7 GBq or higher), significantly predicted both excellent and acceptable responses regardless of the follow-up protocol. CONCLUSIONS: The clinical impact of factors related to response prediction differed depending on the follow-up protocol or classification of response criteria. A high administered activity of RAI was a significant factor predicting a favorable response to therapy regardless of the follow-up protocol or classification of response criteria.

Performance of 68Ga-DOTA-Conjugated Somatostatin Receptor-Targeting Peptide PET in Detection of Pheochromocytoma and Paraganglioma: A Systematic Review and Metaanalysis.

We performed a systematic review and metaanalysis of the performance of 68Ga-DOTA-conjugated somatostatin receptor-targeting peptide (68Ga-DOTA-SST) PET in the detection of pheochromocytomas and paragangliomas (PPGLs). Methods: PubMed and Embase were searched until May 8, 2018. We included studies that reported the detection rate of 68Ga-DOTA-SST PET in patients with PPGLs. Detection rates were pooled using a random-effects model. Subgroup analyses and metaregression were performed to explore the cause of heterogeneity. Results: Thirteen studies were included for qualitative synthesis. Per-lesion detection rates of 68Ga-DOTA-SST PET were consistently higher (ranging from 92% to 100%) than other imaging modalities, including 18F-fluorohydroxyphenylalanine (18F-FDOPA) PET, 18F-FDG PET, and 123/131I-metaiodobenzylguanidine (123/131I-MIBG) scintigraphy. However, in patients with polycythemia/paraganglioma syndrome, the detection rate of 68Ga-DOTA-DOTATATE PET was 35%. Nine studies (215 patients) with no specific inclusion criteria for subtype were quantitatively synthesized. The pooled detection rate was 93% (95% confidence interval [CI], 91%-95%), which was significantly higher than that of 18F-FDOPA PET (80% [95% CI, 69%-88%]), 18F-FDG PET (74% [95% CI, 46%-91%]), and 123/131I-MIBG scan (38% [95% CI, 20%-59%], P < 0.001 for all). A greater prevalence of head and neck paragangliomas was associated with higher detection rates of 68Ga-DOTA-SST PET (P = 0.0002). Conclusion:68Ga-DOTA-SST PET exhibited superior performance for lesion detection, over other functional imaging modalities, in patients with PPGLs, with the exception of polycythemia/paraganglioma syndrome. This might suggest 68Ga-DOTA-SST PET as a first-line imaging modality for the primary staging of PPGL or the restaging of PPGL with unknown genetic status.

Prognostic Value of Volumetric Parameters of Pretreatment 18F-FDG PET/CT in Esophageal Cancer: A Systematic Review and Meta-analysis.

PURPOSE: We performed a systematic review and meta-analysis on the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from pretreatment F-FDG PET/CT in patients with esophageal cancer. METHODS: PubMed and EMBASE databases were searched until April 12, 2018, for studies that evaluated MTV or TLG as prognostic factors in esophageal cancer, with overall survival (OS) and event-free survival serving as the end points. Hazard ratios (HRs) were meta-analytically pooled using a random-effects model. Subgroup analyses based on the clinicopathological and PET variables were performed. RESULTS: In total, 16 studies with 1294 patients were included. The pooled HRs of MTV and TLG for OS were 2.26 (95% confidence interval [CI], 1.73-2.96) and 2.23 (95% CI, 1.73-2.87), respectively. Regarding event-free survival, the pooled HRs of MTV and TLG were 2.03 (95% CI, 1.66-2.49) and 2.57 (95% CI, 1.82-3.62), respectively. Metabolic tumor volume was found to be a significant prognostic factor for OS consistently across multiple subgroups classified based on stage, histological subtype, treatment, delineation of volume of interest, and the determination method of cutoff value, with pooled HRs ranging from 1.96 to 2.54. CONCLUSIONS: In patients with esophageal cancer, MTV and TLG derived from pretreatment F-FDG PET are significant prognostic factors. As prognostic biomarkers, volumetric metabolic parameters may bolster the role of F-FDG PET in the management of esophageal cancer.

Performance of pre-treatment ¹8F-fluorodeoxyglucose positron emission tomography/computed tomography for detecting metastasis in ovarian cancer: a systematic review and meta-analysis.

OBJECTIVE: We describe a systematic review and meta-analysis of the performance of ¹8F-fluorodeoxyglucose (¹8F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting metastasis in ovarian cancer. METHODS: MEDLINE and Embase were searched for diagnostic accuracy studies that used ¹8F-FDG PET or PET/CT for pre-treatment staging, using surgical findings as the reference standard. Sensitivities and specificities were pooled and plotted in a hierarchic summary receiver operating characteristic plot. Potential causes of heterogeneity were explored through sensitivity analyses. RESULTS: Eight studies with 594 patients were included. The overall pooled sensitivity and specificity for metastasis were 0.72 (95% confidence interval [CI]=0.61-0.81) and 0.93 (95% CI=0.85-0.97), respectively. There was considerable heterogeneity in sensitivity (I²=97.57%) and specificity (I²=96.74%). In sensitivity analyses, studies that used laparotomy as the reference standard showed significantly higher sensitivity and specificity (0.77; 95% CI=0.67-0.87 and 0.96; 95% CI=0.92-0.99, respectively) than those including diagnostic laparoscopy (0.62; 95% CI=0.46-0.77 and 0.84; 95% CI=0.69-0.99, respectively). Higher specificity was shown in studies that confirmed surgical findings by pathologic evaluation (0.95; 95% CI=0.90-0.99) than in a study without pathologic confirmation (0.69; 95% CI=0.24-1.00). Studies with a lower prevalence of the FDG-avid subtype showed higher specificity (0.97; 95% CI=0.94-1.00) than those with a greater prevalence (0.89; 95% CI=0.80-0.97). CONCLUSION: Pre-treatment ¹8F-FDG PET/CT shows moderate sensitivity and high specificity for detecting metastasis in ovarian cancer. With its low false-positive rate, it can help select surgical approaches or alternative treatment options.

A Comparison of the Accuracy of Different Single Plasma Sample Methods for Measuring Glomerular Filtration Rate Using 51Cr-EDTA in Children.

PURPOSE: Among the different methods of measuring glomerular filtration rate (GFR) using 51Cr-ethylenediaminetetraacetic acid clearance, the two-plasma-sample method (TPSM) is widely used, and highly accurate. The single-plasma-sample method (SPSM) is occasionally used for simplicity, at the expense of accuracy. Our aims were (1) to investigate the correlation and (2) to compare the accuracy of six known SPSMs in pediatric patients in reference to TPSM. METHODS: We retrospectively reviewed 122 pediatric cases (65 boys, age 7.3 ± 4.6 years) and analyzed 307 GFR measurements. SPSMs included Groth and Aasted at 120 min, Ham at 120 min, Christensen and Groth at 120 and 240 min, and Jacobsson at 120 and 240 min. Reference GFR (GFRref) was defined using TPSM GFR corrected by the Jodal and Brochner-Mortensen equation. GFRref < 30 mL min-1 1.73 m-2 were excluded. The standard error of the estimate (SEE) and the number of cases with differences > 10% (N10%) were used to evaluate accuracy. RESULTS: SPSMs generally correlated well with GFRref (r = 0.92~0.99) and were relatively accurate (SEE = 9.21~15.60). Groth and Aasted showed the smallest SEE, while Jacobsson at 240 min showed the smallest N10% for all GFRref ranges. As for the decreased GFRref, Ham was most accurate followed by Jacobsson at 240 min. CONCLUSIONS: Jacobsson at 240 min provided good accuracy in all GFRref ranges and was well correlated with TPSM. Jacobsson at 240 min might be the most appropriate method to substitute for TPSM in pediatric patients. Ham could be an alternative in patients with impaired renal function.

A systematic review of the prognostic value of texture analysis in 18F-FDG PET in lung cancer.

OBJECTIVE: The aim of this study was to perform a systematic review of the prognostic value of texture parameters derived by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with lung cancer. METHODS: PubMed and EMBASE databases were searched up to March 12, 2018, for original articles involving texture analysis for the prediction of prognosis in patients with lung cancer. Risk of bias in the studies was critically assessed using the QUIPS tool. The results of survival analysis in the included studies were compared. RESULTS: Of the 446 articles retrieved, 17 studies were eligible for inclusion. Our review suggests that the prognostic value of texture parameters in lung cancer remains unproven. Most studies had a moderate to high risk of bias. Texture parameters that described prognosis were not replicated across studies. Conflicting results on hazard ratios were found among the studies. This discrepancy is partly explained by false-positive findings originating from statistical error and variability caused by different methodologies used for image acquisition and processing in the included studies. CONCLUSION: Based on currently available evidence, there is insufficient evidence to support the prognostic value of texture analysis in 18F-FDG PET in lung cancer. Further studies implementing well-established methodologies and statistical evidence are warranted for proper validation of these promising imaging biomarkers.

Thyroid Incidentalomas Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography: Malignant Risk Stratification and Management Plan.

OBJECTIVE: The aims of this study were to stratify the risk of malignancy in thyroid incidentalomas detected on 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET/CT) using ultrasound features according to guidelines for thyroid nodules and to develop a subsequent management plan. METHODS: From a historical cohort of 96,942 consecutive patients who underwent 18F-FDG PET/CT between October 2008 and September 2015, 1342 patients with 1364 nodules underwent ultrasound evaluation for focal uptake in thyroid gland, with a final diagnosis made for 877 patients with 907 nodules, which were included in this study. Ultrasound images were retrospectively reviewed, and they were stratified according to the American Thyroid Association and Korean Thyroid Image Reporting and Data System guidelines. The calculated malignancy risks were compared with the estimated risks suggested by the guidelines. RESULTS: The overall malignancy risk of thyroid incidentalomas detected on 18F-FDG PET/CT was 54.7%. When stratified according to the American Thyroid Association guidelines, the malignancy risks of thyroid incidentalomas with high and intermediate suspicion (93.2% and 45.2%, respectively) were higher than those indicated in the guidelines. The malignancy risks of thyroid incidentalomas with low and very low suspicion (8.1% and 0%, respectively) were within the guideline ranges. These findings were also noted when thyroid incidentalomas were stratified according to the Korean Thyroid Image Reporting and Data System, and in a subgroup of nodules >1 cm. CONCLUSIONS: Ultrasound examinations can be used to stratify the malignancy risk of thyroid incidentalomas detected on 18F-FDG PET/CT. The risk of malignancy did not increase in thyroid incidentalomas with low and very low suspicion, indicating that only selective biopsies may be needed in these categories of thyroid incidentalomas.

Preoperative [18F]FDG PET/CT tumour heterogeneity index in patients with uterine leiomyosarcoma: a multicentre retrospective study.

PURPOSE: We investigated the prognostic value of the tumour heterogeneity index determined on preoperative [18F]FDG PET/CT in patients with uterine leiomyosarcoma (LMS). METHODS: We retrospectively reviewed patients with uterine LMS who underwent preoperative [18F]FDG PET/CT scans at three tertiary referral hospitals. The PET/CT parameters maximum standardized uptake value of the primary tumour (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis were assessed. The negative values of the MTV linear regression slope (nMLRS) according to the SUV thresholds of 2.5 and 3.0 were determined as the tumour heterogeneity index. The value of PET/CT-derived parameters in predicting progression-free survival (PFS) and overall survival (OS) were determined in regression analyses. RESULTS: Clinicopathological and PET/CT data from 16 patients were reviewed. The median postsurgical follow-up was 21 months (range 4-82 months), and 12 patients (75.0%) experienced recurrence. Tumour size (P = 0.017), SUVmax (P = 0.019), MTV (P = 0.016) and nMLRS (P = 0.008) were significant prognostic factors for recurrence. MTV (P = 0.048) and nMLRS (P = 0.045) were significant prognostic factors for patient survival. nMLRS was correlated with clinicopathological parameters including tumour size (Pearson's correlation coefficient γ = 0.825, P < 0.001) and lymph node metastasis (γ = 0.721, P = 0.004). Patient groups categorized according to the nMLRS cut-off value showed significant differences in PFS (P = 0.033) and OS (P = 0.044). CONCLUSION: The preoperative tumour heterogeneity index obtained using the MTV linear regression slope may be a novel and useful prognostic marker in uterine LMS.

Diagnostic value of integrated ¹8F-fluoro-2-deoxyglucose positron emission tomography/computed tomography in recurrent epithelial ovarian cancer: accuracy of patient selection for secondary cytoreduction in 134 patients.

OBJECTIVE: The aim of this study was to evaluate the diagnostic value of integrated ¹8F-fluoro-2-deoxyglucose-positron emission tomography/computed tomography (¹8F-FDG-PET/CT) for suspected recurrence of epithelial ovarian cancer (EOC) with non-disseminated lesions. METHODS: We retrospectively reviewed the medical records of recurrent EOC patients who underwent secondary cytoreduction from January 2000 to December 2013. A total of 134 patients underwent secondary cytoreduction after imaging with either ¹8F-FDG-PET/CT or contrast-enhanced computed tomography (CECT). RESULTS: In a patient-based analysis of 134 patients, 124 (92.5%) were confirmed to be positive for malignancy. Among 72 patients with suspected non-disseminated recurrence on ¹8F-FDG-PET/CT, 65 (89.0%) were confirmed to have recurrence, giving 98.5% sensitivity, 87.7% accuracy, and 88.9% positive predictive value (PPV). In the 65 patients with recurrence, residual tumor remained in 14 patients, giving an accuracy of patient selection for secondary cytoreduction of 69.4% (50/72) and it is higher than that of CECT (64.0%). In 169 lesions removed from patients who underwent preoperative ¹8F-FDG-PET/CT, 135 (79.9%) were confirmed to be positive for malignancy and 124 were accurately detected by ¹8F-FDG-PET/CT, giving 91.9% sensitivity, 81.1% accuracy, and 85.5% PPV. Foreign body granuloma was found in 33.3% of 21 lesions with false-positive ¹8F-FDG-PET/CT findings (7/21). The mean preoperative cancer antigen 125 (CA-125) level in false-positive patients was 28.8 U/mL. CONCLUSION: Compared with CECT, ¹8F-FDG-PET/CT shows higher sensitivity in lesion-based analysis and better accuracy of patient selection for secondary cytoreduction. However, there is still a need for integration of the results of ¹8F-FDG-PET/CT, CECT, and CA-125 levels to aid treatment planning.