Dual Time Point Imaging Research Articles

Clinical application of 18F-FCH PET/CT in the diagnosis and treatment of hyperparathyroidism.

We evaluated the difference in parathyroid visualization on 18F-FCH PET/CT images obtained at 5 and 60min, and quantitatively analyzed the mode of FCH uptake at different time points, to determine the best imaging time for FCH PET/CT. This retrospective study included 73 patients with hyperparathyroidism (HPT) who underwent 18F-FCH PET/CT imaging between December 2017 and December 2021. The diagnostic efficiency of 5- and 60-min dual time point imaging for the diagnosis of hyperparathyroidism and parathyroid adenoma and hyperplasia, were compared using visual and quantitative analyses. Dual-time 18F-FCH PET/CT imaging visual analysis had diagnostic value for HPT. The receiver operating characteristic curve of PET/CT quantitative parameters for the diagnosis of HPT and lesions showed that the parathyroid/thyroid SUVmax ratio for 60-min imaging had a higher sensitivity and specificity (based on patient, sensitivity: 90.90% and specificity: 85.71%; based on focus, sensitivity: 83.06% and specificity: 85.71%) compared to that for 5-min imaging. PET/CT quantitative parameters can distinguish parathyroid adenoma and hyperplasia. The 60-min parathyroid SUVmax value had the highest diagnostic value (cutoff: 3.945; area under the curve: 0.783). The quantitative parameters of 60min 18F-FCH PET/CT have more advantages in aiding in the pathologica diagnosis and clinical treatment of HPT.

18F-FDG PET–CT dual-time imaging in detection and characterization of recurrent lesions in patients with testicular cancer

BackgroundTesticular cancer is the second most frequent form of male genital tumors. Globally, testicular malignancy has risen over the last forty years. Among malignant testicular tumors, germ cell tumors represent approximately 95% of all tumors. They are classified into seminomatous and non-seminomatous tumors as they differ in clinical features, therapy, and prognosis. Despite the increasing value of whole-body fluorodeoxyglucose positron emotion tomography/computerized tomography (18FDG-PET/CT) for all malignancies, the practical function of this imaging method in testicular germ cell tumors is still unknown. We aim to assess the diagnostic performance of18FDG-PET/CT dual-time-point imaging (DTPI) in the detection and characterization of recurrent testicular cancer lesions.Results18FDG-PET/CT DTPI showed higher specificity (SP) in lesions' delectability and characterization for local, nodal, and distant lesions than the single-time-point imaging (STPI) (97.6%, 93.8%, and 97% versus 95.2%, 68.8%, and 84.8%, respectively) and higher sensitivity (SN) for nodal and distant lesions (97% and 93.8% versus 87.8% and 87.5%, respectively). The mean SUVmaxD and the RI values—not the SUVmaxE—of the malignant lesions were significantly greater than the benign lesions (p 0.001*).Conclusions18FDG-PET/CT DTPI and its related indices (SUVmaxD and the RI) are more accurate, sensitive, and specific than the STPI in the characterization of recurrent lesions in testicular cancer patients.

Dual time point imaging in locally advanced head and neck cancer to assess residual nodal disease after chemoradiotherapy

BackgroundFDG-PET/CT has a high negative predictive value to detect residual nodal disease in patients with locally advanced squamous cell head and neck cancer after completing concurrent chemoradiotherapy (CCRT). However, the positive predictive value remains suboptimal due to inflammation after radiotherapy, generating unnecessary further investigations and possibly even surgery. We report the results of a preplanned secondary end point of the ECLYPS study regarding the potential advantages of dual time point FDG-PET/CT imaging (DTPI) in this setting. Standardized dedicated head and neck FDG-PET/CT images were obtained 12 weeks after CCRT at 60 and 120 min after tracer administration. We performed a semiquantitative assessment of lymph nodes, and the retention index (RI) was explored to optimize diagnostic performance. The reference standard was histology, negative FDG-PET/CT at 1 year, or > 2 years of clinical follow-up. The time-dependent area under the receiver operator characteristics (AUROC) curves was calculated.ResultsIn total, 102 subjects were eligible for analysis. SUV values increased in malignant nodes (median SUV1 = 2.6 vs. SUV2 = 2.7; P = 0.04) but not in benign nodes (median SUV1 = 1.8 vs. SUV2 = 1.7; P = 0.28). In benign nodes, RI was negative although highly variable (median RI = − 2.6; IQR 21.2), while in malignant nodes RI was positive (median RI = 12.3; IQR 37.2) and significantly higher (P = 0.018) compared to benign nodes. A combined threshold (SUV1 ≥ 2.2 + RI ≥ 3%) significantly reduced the amount of false-positive cases by 53% (P = 0.02) resulting in an increased specificity (90.8% vs. 80.5%) and PPV (52.9% vs. 37.0%), while sensitivity (60.0% vs. 66.7%) and NPV remained comparably high (92.9% vs. 93.3%). However, AUROC, as overall measure of benefit in diagnostic accuracy, did not significantly improve (P = 0.62). In HPV-related disease (n = 32), there was no significant difference between SUV1, SUV2, and RI in malignant and benign nodes, yet this subgroup was small.ConclusionsDTPI did not improve the overall diagnostic accuracy of FDG-PET/CT to detect residual disease 12 weeks after chemoradiation. Due to differences in tracer kinetics between malignant and benign nodes, DTPI improved the specificity, but at the expense of a loss in sensitivity, albeit minimal. Since false negatives at the 12 weeks PET/CT are mainly due to minimal residual disease, DTPI is not able to significantly improve sensitivity, but repeat scanning at a later time (e.g. after 12 months) could possibly solve this problem. Further study is required in HPV-associated disease.

Радіонуклідна модель «dual time point imaging» у прогнозуванні параендопротезних ускладнень при ендопротезуванні кульшових і колінних суглобів

Вступ. Останніми десятиріччями в світі зафіксовано зростання кількості хворих на деформуючий остеоартроз різної етіології від 19,8 до 63 %. В Україні поширеність остеоартрозу становить 2200,6 на 100 000 населення, в Америці — 6500 на 100 000 населення. В той же час залишаються не повністю вивченими питання визначення остеосцинтиграфічних параметрів, при яких можливо спрогнозувати в передопераційному періоді параендопротезні ускладнення з метою проведення ендопротезування без ризику їх виникнення. Мета. Ви-значення діагностичної ролі радіонуклідного методу у прогнозуванні параендопротезних ускладнень у хворих на деформуючий остеоартроз кульшових і колінних суглобів шляхом розробки сцинтиграфічної моделі «dual time point imaging». Матеріали та методи. Трифазова остеосцинтиграфія проводилась на томографічній сцинтиляційній гамма-камері «Тамара-301Т» за стандартним протоколом: І етап — ангіографічна фаза, проводилась одразу після внутрішньовенного болюсного введення 600–800 МБк 99mTc-метилендифосфонату; ІІ етап — рання статична фаза, виконувалась у статичному режимі одразу після закінчення ангіографічної фази, збір інформації протягом 120 секунд; ІІІ етап — відстрочена статична фаза, проводилась через 2–4 години після введення радіофармацевтичного препарату (РФП), виконувалась у статичному режимі. Результати. При деформуючому остеоартрозі відбувалась швидка елімінація радіологічного індикатора з патологічного вогнища у зв’язку з активним вимиванням РФП внаслідок зниження кровопостачання тканин ділянки. У вогнищах ревматоїдного артриту, навпаки, спостерігалось зростання відсотка накопичення індикатора через інтенсифікацію інтегральної перфузії цих ділянок, за рахунок підвищення проникності судин внаслідок дії інфекційних агентів, активації факторів резорбції та синтезу мінеральних компонентів, ангіогенезу. Встановлено позитивну вірогідну кореляцію між показниками сцинтиграфічних параметрів включення РФП до ендопротезування та кількістю післяопераційних імплант-асоційованих ускладнень, а саме: між показниками сцинтиграфії при ревматоїдних артритах і кількістю випадків гематогенної суглобової інфекції в післяопераційний період — через 1 рік після ендопротезування (r = 0,581; p < 0,05). Висновки. Застосування радіонуклідної моделі «dual time point imaging» сприяє ранньому виявленню та зниженню відсотка параендопротезних ускладнень у післяопераційний період, зменшенню кількості виконання ревізійних ендопротезувань і скороченню терміну реабілітаційно-відновлювальних заходів після ендопротезування кульшових і колінних суглобів.

Dual time point imaging of staging PSMA PET/CT quantification; spread and radiomic analyses.

The aims were to evaluate the performance of models that predict Gleason Grade (GG) groups with radiomic data obtained from the prostate gland in dual time 68Ga-Prostate Specific Membrane Antigen (PSMA) Positron Emission Tomography/Computerized Tomography (PET/CT) images for prostate cancer (PCa) staging, and to analyze the contribution of late imaging to the radiomic model and to evaluate the relationship of the distance between tumor foci in the body (Dmax) obtained in early PET images with histopathology and prostate specific antigen (PSA) value. Between October 2020 and August 2021, 41 patients who underwent 68Ga-PSMA PET/CT for staging of PCa were retrospectively analyzed. Volumetric and radiomics data were obtained from early and late PSMA PET images. The differences between age, metastasis status, PSA, standard uptake value (SUV), volumetric and radiomics parameters between GG groups were analyzed. Early and late PET radiomic models were created, area under curve (AUC), sensitivity, specificity and accuracy values of the models were obtained. In addition, the correlation of Dmax values with total PSMA-tumor volume (TV), Total lesion (TL)-PSMA and PSA values was evaluated. In metastatic patients, the difference in Dmax between GG groups was analyzed. There was a significant difference between patients with GG ≤ 3 and > 3 in 35 of the early PET radiomic features. In the early PET model, multivariate analyses showed that GLRLM_RLNU and PSA were the most meaningful parameters. The AUC, sensitivity, specificity and accuracy values of the early model in detecting patients with GG > 3 were calculated as 0.902, 76.2%, 84% and 78.1%, respectively. In 36 late PET radiomic features, there was a significant difference between patients with GG ≤ 3 and > 3. In multivariate analyses; SHAPE_compacity and PSA were obtained as the most meaningful parameters. The AUC, sensitivity, specificity and accuracy values of the late model in detecting patients with GG > 3 were calculated as 0.924, 85.7%, 85% and 85.4%. There was a strong correlation between Dmax and PSA values (p < 0.001, rho: 0.793). Dmax showed strong correlation with PSMA-TVtotal and TL-PSMAtotal (p < 0.001, rho: 0.797; p < 0.001, rho: 0.763, respectively). In patients with metastasis, median Dmax values of the GG > 3 group were higher than GG ≤ 3 group; A statistically significant difference was obtained between these two groups (p=0.023). Model generated from the late PSMA PET radiomic data had better performance in the current study. Without the use of invasive methods, the heterogeneity and aggressiveness of the primary tumor and the prediction of GG groups may be possible with 68Ga-PSMA PET/CT images obtained for diagnostic purposes especially with late PSMA PET/CT imaging.

68Ga-PSMA11 PET/CT for biochemically recurrent prostate cancer: Influence of dual-time and PMT- vs SiPM-based detectors

Objectives68Ga-PSMA11 PET/CT is excellent for evaluating biochemically recurrent prostate cancer (BCR PC). Here, we compared the positivity rates of dual-time point imaging using a PET/CT scanner (DMI) with silicon photomultiplier (SiPM) detectors and a PET/CT scanner (D690) with photomultiplier tubes (PMT), in patients with BCR PC. MethodsFifty-eight patients were prospectively recruited and randomized to receive scans on DMI followed by D690 or vice-versa. Images from DMI were reconstructed using the block sequential regularized expectation maximization (BSREM) algorithm and images from D690 were reconstructed using ordered subset expectation maximization (OSEM), according to the vendor's recommendations. Two readers independently reviewed all images in randomized order, recorded the number and location of lesions, as well as standardized uptake value (SUV) measurements. ResultsTwenty-eight patients (group A) had DMI as first scanner followed by D690, while 30 patients (group B) underwent scans in reversed order. Mean PSA was 30±112.9 (range 0.3–600.66) ng/mL for group A and 41.5 ± 213.2 (range 0.21–1170) ng/mL for group B (P = 0.796). The positivity rate in group A was 78.6% (22/28 patients) vs. 73.3% (22/30 patients) in group B. Although the performance of the two scanners was equivalent on a per-patient basis, DMI identified 5 additional sites of suspected recurrent disease when used as first scanner. The second scan time point did not reveal additional abnormal uptake. ConclusionsThe delayed time point in 68Ga-PSMA11 PET/CT did not show a higher positivity rate. SiPM-based PET/CT identified additional lesions. Further studies with larger cohorts are needed to confirm these results.

18 F-FDG-PET/MRI in patients with Graves\u2019 orbitopathy.

PurposeCurrently, therapeutic management of patients with Graves’ orbitopathy (GO) relies on clinical assessments and MRI. However, monitoring of inflammation remains difficult since external inflammatory signs do not necessarily represent the orbital disease activity. Therefore, we aimed to evaluate the diagnostic value of 18F-FDG-PET/MRI to assess the inflammation of GO patients.MethodsEnrolled patients with new onset of GO underwent ophthalmological examinations to evaluate the activity (CAS) and severity of GO (NOSPECS), as well as an 18F-FDG-PET/MRI (Siemens Biograph mMR) with dual time point imaging (immediately post-injection and 60 min p.i.). A subset of PET parameters including maximum standardized uptake value (SUVmax), metabolic target volume (MTV), and total lesion glycolysis (TLG) were obtained separately per eye and per extraocular eye muscle (EOM). EOM thickness was measured on the co-registered MRI.ResultsOf 14 enrolled patients, three showed mild, seven moderate-to-severe, and four sight-threatening GO. Patients with severe GO showed statistically significant higher TLG than patients with mild GO (p = 0.02) and higher MTV than patients with mild (p = 0.03) and moderate (p = 0.04) GO. Correlation between NOSPECS on one hand and MTV and TLG on the other was significant (R2 = 0.49–0.61).ConclusionTLG and MTV derived from FDG-PET appear to be good discriminators for severe vs. mild-to-moderate GO and show a significant correlation with NOSPECS. As expected, PET parameters of individual eye muscles were not correlated with associated eye motility, since fibrosis, and not inflammation, is mainly responsible for restricted motility. In conclusion, 18F-FDG-PET/MRI can be used for assessment of GO inflammation.

Equivalent tumor detection for early and late FAPI-46 PET acquisition

IntroductionPositron emission tomography (PET) using small ligands of the fibroblast activation protein (FAP) was recently introduced. However, optimal uptake time has not been defined yet. Here, we systematically compare early (~ 10 min p.i.) and late (~ 60 min p.i.) FAPI-46 imaging in patients with various types of cancer.MethodsThis is a retrospective single-institutional study. Imaging was performed at the Essen University Hospital, Germany. A total of 69 patients who underwent dual time-point imaging for either restaging (n = 52, 75%) or staging (n = 17, 25%) of cancer were included. Patients underwent PET with two acquisitions: early (mean 11 min, SD 4) and late (mean 66 min, SD 9). Mean injected activity was 148 MBq (SD 33).ResultsIn total, 400 lesions were detected in 69 patients. Two of 400 (0.5%) lesions were only seen in early time-point imaging but not in late time-point imaging. On a per-patient level, there was no significant difference between SUVmax of hottest tumor lesions (Wilcoxon: P = 0.73). Organ uptake demonstrated significant early to late decrease in SUVmean (average ∆SUVmean: − 0.48, − 0.14, − 0.27 for gluteus, liver, and mediastinum, respectively; Wilcoxon: P < 0.001). On a per-lesion basis, a slight increase of SUVmax was observed (average ∆SUVmax: + 0.4, Wilcoxon: P = 0.03).ConclusionIn conclusion, early (~ 10 min p.i.) versus late (~ 60 min p.i.) FAPI-46 imaging resulted in equivalent lesion uptake and tumor detection. For improved feasibility and scan volume, we implement early FAPI-46 PET in future clinical and research protocols.

Dual-Time Point [68Ga]Ga-PSMA-11 PET/CT Hybrid Imaging for Staging and Restaging of Prostate Cancer.

Simple SummaryEarly diagnosis and tumor characterization of prostate cancer (PCa) are important for accurate treatment. [68Ga]Ga-PSMA-11 PET/CT turns out to constitute a major step toward improved diagnostic procedures to detect primary, recurrent, and metastatic PCa. The aim of our study is to evaluate the effect of a second imaging modality for the staging and restaging of PCa by possibly detecting additional PCa lesions due to the well-known increase of PSMA uptake over time. There was a significant increase in tracer uptake on delayed images in comparison to early [68Ga]Ga-PSMA-11 PET/CT in our study, but the lesion positivity rate was comparable. However, in a few individual cases, additional delayed scans provided an information advantage in PCa lesion detection. The findings of our study are likely to be of major interest to clinicians as well as to researchers defining the algorithms that are necessary to implement this promising method with its specific tracer into clinical routine.Routine [68Ga]Ga-PSMA-11 PET/CT (one hour post-injection) has been shown to accurately detect prostate cancer (PCa) lesions. The goal of this study is to evaluate the benefit of a dual-time point imaging modality for the staging and restaging of PCa patients. Biphasic [68Ga]Ga-PSMA-11 PET/CT of 233 patients, who underwent early and late scans (one/three hours post-injection), were retrospectively studied. Tumor uptake and biphasic lesion detection for 215 biochemically recurrent patients previously treated for localized PCa (prostatectomized patients (P-P)/irradiated patients (P-I) and 18 patients suspected of having primary PCa (P-T) were separately evaluated. Late [68Ga]Ga-PSMA-11 PET/CT imaging detected 554 PCa lesions in 114 P-P patients, 187 PCa lesions in 33 P-I patients, and 47 PCa lesions in 13 P-T patients. Most patients (106+32 P-P/P-I, 13 P-T) showed no additional PCa lesions. However, 11 PSMA-avid lesions were only detected in delayed images, and 33 lesions were confirmed as malignant by a SUVmax increase. The mean SUVmax of pelvic lymph node metastases was 25% higher (p < 0.001) comparing early and late PET/CT. High positivity rates from routine [68Ga]Ga-PSMA-11 PET/CT for the staging and restaging of PCa patients were demonstrated. There was no decisive influence of additional late imaging with PCa lesion detection on therapeutic decisions. However, in a few individual cases, additional delayed scans provided an information advantage in PCa lesion detection due to higher tracer uptake and improved contrast.

Diagnostic accuracy of visual analysis versus dual time-point imaging with 18F-FDG PET/CT for the characterization of indeterminate pulmonary nodules with low uptake

ObjectiveTo determine the accuracy of visual analysis and the retention index (RI) with dual-time point 18F-FDG PET/CT for the characterization of indeterminate pulmonary nodules (IPN) with low FDG uptake. Materials and methodsA retrospective analysis was performed on 43 patients (28 men, 64±11 years old, range 36–83 years) referred for IPN characterization with 18F-FDG-PET/CT and maximum standard uptake value ≤2.5 at 60min post-injection (SUVmax1). Nodules were analyzed by size, visual score for FDG uptake on standard (OSEM 2,8) and high definition (HD) reconstructions, SUVmax1, SUVmax at 180min post-injection (SUVmax2), and RI was calculated. The definitive diagnosis was based on histopathological confirmation (n=28) or ≥2 years of follow-up. ResultsTwenty-four nodules (56%) were malignant. RI≥10% on standard reconstruction detected 18 nodules that would have been considered negative using the standard SUVmax≥2.5 criterion for malignancy. RI≥10% had a sensitivity, specificity, PPV, NPV and accuracy of 75%, 73.7%, 78.3%, 70%, and 74.4%, respectively, while for FDG uptake>liver on HD these were 79.1%, 63.2%, 73.1%, 70.6%, and 72.1%, respectively. SUVmax1≥2, SUVmax2>2.5 and FDG uptake>liver on standard reconstruction had a PPV of 100%. FDG uptake>mediastinum on HD had a NPV of 100%. ConclusionsRI≥% was the most accurate criterion for malignancy, followed by FDG uptake>liver on HD reconstruction. On standard reconstruction, SUVmax1≥2 was highly predictive of malignancy, as well as SUVmax2>2.5 and FDG uptake>liver. FDG uptake<mediastinum on HD was highly predictive of benign nodules.

The role of 18FDG PET/CT imaging of aortic atherosclerosis: prospective study and technique optimization

BackgroundAtherosclerosis is an inflammatory disease of the inner wall of large and medium-sized arteries. The progress of atherosclerosis based on a lot of factors, including systemic involvement of disease, the precise vascular arterial affection, and the degree of flow obstruction. We aim in this study to estimate the FDG uptake of the aortic wall in the early and delayed imaging and to correlate this with the morphologic changes detected by CT.ResultsThis is a prospective study that was performed through 1 year. The study included 50 patients [30 males (60%) and 20 females (40%)] with male to female mean ratio 1.5:1 and their mean age 58.3 ± 15.7 years. Each patient underwent dual time-point 18F-FDG PET CT imaging at ~ 60 min (Early images) and 180 min (delayed images) after the administration of 18F-FDG. For each patient, the global 18F-FDG uptake in the aorta was determined by manually drawing regions of interest (ROIs) around the outer part of the arterial wall on every slice of the attenuation-corrected transverse PET CT images. Per-patient, per-time-point, per-vessel, and per-ROI radiotracer decay-corrected and body weight-corrected SUVs were calculated, resulting in a single mean value of maximum SUV for the aorta. The aortic wall FDG uptake was measured in both early and delayed images and expressed in terms of SUVmax. Then Retention index percentage of the aorta was measured. The retention index percentage was calculated by subtracting the SUVmax in early images from the SUVmax in delayed images and dividing by SUVmax in early images.ConclusionAortic wall FDG uptake can be used as an additional parameter as well as a biomarker on evaluation of the arterial atherosclerotic activity. Delayed post 3 h FDG imaging is more accurate than the routine early post 1 h imaging in evaluating the atherosclerotic activity.

The clinical value of texture analysis of dual-time-point 18F-FDG-PET/CT imaging to differentiate between 18F-FDG-avid benign and malignant pulmonary lesions.

To examine whether the texture analysis of dual-time-point (DTP) F-18-fluorodeoxyglucose (18F-FDG)-PET/CT imaging can differentiate between 18F-FDG-avid benign and malignant pulmonary lesions. We compared standardized uptake value (SUV)-related (SUVmax [g/ml] and SUVmean [g/ml]), volumetric (metabolic tumor volume [MTV] [cm3] and total lesion glycolysis [TLG] [g]), and texture (entropy, homogeneity, dissimilarity, intensity variability [IV], size-zone variability [SZV], and zone percentage [ZP]) (MTV ≥ 5.0 cm3 and SUV ≥ 2.5 g/ml) parameters between 13 benign and 46 malignant lesions using the Mann-Whitney U test. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis. Stepwise logistic regression analysis was performed to identify and use the independent variables that correctly differentiate between benign and malignant lesions. Malignant pulmonary lesions showed significantly higher SUVmax, SUVmean, MTV, TLG, entropy, dissimilarity, IV, and SZV and significantly lower homogeneity and ZP than benign pulmonary lesions (all p < 0.05) in both early and delayed images. Their areas under the ROC curves (AUCs) ranged between 0.69 and 0.94, and diagnostic accuracies between 64.4% and 93.2%. Entropy-early (p = 0.014), SUVmean-delay (p = 0.039), and dissimilarity-delay (p = 0.027) were independent parameters, and combined use of them yielded the highest AUC (0.98) with 100% sensitivity (46/46), 84.6% specificity (11/13), and 96.7% (57/59) accuracy for distinguishing between benign and malignant lesions. The individual early and delayed SUV-related, volumetric, and texture parameters showed a wide range of accuracy. Combined use of independent parameters extracted from DTP imaging might yield a high diagnostic accuracy with balanced sensitivity and specificity to differentiate between benign and malignant 18F-FDG-avid pulmonary lesions. • Malignant pulmonary lesions showed significantly higher SUV-related (SUVmax and SUVmean) and volumetric (MTV and TLG) parameters than benign pulmonary lesions in both early and delayed images. • Malignant pulmonary lesions showed significantly more heterogeneous18F-FDG uptake than benign pulmonary lesions in both early and delayed images. • Combined use of independent parameters extracted from DTP imaging might yield a high diagnostic accuracy to differentiate between benign and malignant18F-FDG-avid pulmonary lesions.

Prognostic Value of the Volumetric Parameters of Dual-Time-Point 18F-FDG PET/CT in Non-Small Cell Lung Cancer Treated With Definitive Radiation Therapy.

OBJECTIVE. The purpose of this study is to assess the effectiveness of the volumetric parameters of dual-time-point imaging (DTPI) with 18F-FDG PET (DTPI FDG PET) in predicting the prognosis of patients with non-small cell lung cancer (NSCLC) treated with definitive radiation therapy (RT). MATERIALS AND METHODS. The records of consecutive patients who received definitive RT for NSCLC from April 2010 to April 2017 were retrospectively reviewed. Pretreatment DTPI FDG PET images were routinely obtained as part of the PET/CT examination. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor (SUVmax-T, MTV-T, and TLG-T, respectively) and those of the primary tumor and lymph nodes (N) combined (SUVmax-TN, MTV-TN, and TLG-TN, respectively) were used as variables, and the percentage change in these parameters (change in SUVmax [ΔSUVmax], change in MTV [ΔMTV], and change in TLG [ΔTLG]) on DTPI FDG PET were analyzed. RESULTS. Of the 118 patients identified and reviewed, 59 met the study eligibility criteria. After a median follow-up of 23.3 months, the 3-year local control rate (LCR) and disease-specific survival rates were 53.5% and 45.0%, respectively. On multivariate analysis, significant predictors of LCR were TLG-T and change in TLG-TN (ΔTLG-TN), and significant predictors of disease-specific survival were adjuvant chemotherapy, treatment response, TLG-T, and change in TLG-T (ΔTLG-T). Low percentage changes in ΔTLG (< 41.0% for ΔTLG-T and < 32.0% for ΔTLG-TN) correlated with poor LCR and disease-specific survival. SUVmax and MTV were not significant predictors of both LCR and disease-specific survival. CONCLUSION. TLG and ΔTLG were significant prognostic factors in patients with NSCLC treated with definitive RT. In particular, a relatively low ΔTLG resulted in poor outcomes in terms of LCR and disease-specific survival.

Using neighborhood gray tone difference matrix texture features on dual time point PET/CT images to differentiate malignant from benign FDG-avid solitary pulmonary nodules

ObjectiveLung cancer usually presents as a solitary pulmonary nodule (SPN) on diagnostic imaging during the early stages of the disease. Since the early diagnosis of lung cancer is very important for treatment, the accurate diagnosis of SPNs has much importance. The aim of this study was to evaluate the discriminant power of dual time point imaging (DTPI) PET/CT in the differentiation of malignant and benign FDG-avid solitary pulmonary nodules by using neighborhood gray-tone difference matrix (NGTDM) texture features.MethodsRetrospective analysis was carried out on 116 patients with SPNs (35 benign and 81 malignant) who had DTPI 18F-FDG PET/CT between January 2005 and May 2015. Both PET and CT images were acquired at 1 h and 3 h after injection. The SUVmax and NGTDM texture features (coarseness, contrast, and busyness) of each nodule were calculated on dual time point images. Patients were randomly divided into training and validation datasets. Receiver operating characteristic (ROC) curve analysis was performed on all texture features in the training dataset to calculate the optimal threshold for differentiating malignant SPNs from benign SPNs. For all the lesions in the testing dataset, two visual interpretation scores were determined by two nuclear medicine physicians based on the PET/CT images with and without reference to the texture features.ResultsIn the training dataset, the AUCs of delayed busyness, delayed coarseness, early busyness, and early SUVmax were 0.87, 0.85, 0.75 and 0.75, respectively. In the validation dataset, the AUCs of visual interpretations with and without texture features were 0.89 and 0.80, respectively.ConclusionCompared to SUVmax or visual interpretation, NGTDM texture features derived from DTPI PET/CT images can be used as good predictors of SPN malignancy. Improvement in discriminating benign from malignant nodules using SUVmax and visual interpretation can be achieved by adding busyness extracted from delayed PET/CT images.

Impact of 18F-FDG PET/CT Dual Time Point Imaging in Lymphoma Patients with Lung Lesions.

The aim of: this prospective study was to assess the role of dual time imaging PET/CT study in characterization of the lung lesions in lymphoma patients with lung lesion. Patients and methods: The study was conducted on 28 lymphoma patients. Scan 1 (early image) was performed at 50 min and scan 2 (delayed image) at 110 min after FDG IV injection. The majority of final decisions were reached based on clinical and radiological follow up and the minority was pathologically based. SUV max was calculated at early and delayed images. The difference between early and delayed SUV max (D-SUV max) and the retention index (RI-SUV max) were estimated. Then their cut-off values were evaluated using area under the curve (AUC) from receiver operating characteristic (ROC) analysis. Also, the median quantitative analysis for these parameters was used. Results: Thedelayed SUV max cut-off value of 4.9 giving sensitivity of 90% and specificity of 72% (P=0.004). The cut-off value of D-SUV max of 0.55 yielding a sensitivity of 90% and specificity of 78% (P=0.001). Using 7.5% as a cut-off value of RI-SUV max had sensitivity of 80% and specificity of 67% (P=0.04). The delayed SUV max and D-SUV max had AUCs (0.825 & 0.894 respectively) which is statistically greater than of early SUV max (0.789). The D-SUV max has the largest AUC between the four indices. The median quantitative analysis for Delayed-SUV max was 4.9 (P=0.003), D-SUV max was 0.50 (P=0.001), RI-SUV max was 0.75 (P=0.01). Conclusion: The delayed time point PET/CT imaging is additive technique with higher sensitivity and specificity to characterize lung lesions in lymphoma patients.

Is Dual-Time-Point Imaging Necessary for Discrimination of Adrenal Benign Lesions Versus Malignant Masses: A Study Comparing Standard Methods with Dual-Time-Point FDG PET-CT Imaging

Objectives: This retrospective study was designed to investigate the clinical role of FDG PET-CT, for the evaluation of adrenal lesions and to compare the standart methods with dual-time-point imaging (DTPI) method to distinguish benign from malignant lesions in various cancer patients.Materials and methods: A total of 60 patients with confirmed primary malignancies underwent PET-CT examinations. Of the 60 patients, 79 adrenal lesions (36 benign and 43 malignant adrenal lesions) were shown by CT. Patients were grouped as benign adrenal group (I), malignant adrenal group (II) and dual-phase-group (III).Results: A total of 20 (33%) patients were included in benign adrenal group (Group I) with 28 adrenal lesions. Mean SUVmax value 2.95 were evaluated. All adrenal lesions in Group I had SUVmax value below cut-off 4.2 except 2. A total of 19 (32%) patients were included in malignant adrenal group (Group II) with 22 adrenal lesions. Mean SUVmax value 8.16 were evaluated. All adrenal lesions in Group II had SUVmax value over cut-off 4.2 except 2. A total of 21 (35%) patients were included in dual phase adrenal group (Group III) with 29 adrenal lesions. For malignant adrenal lesions in group III, all of the 21 malign lesions showed increased FDG uptake and SUVmax value in late imaging.Conclusion: Dual time point imaging of PET-CT seems to be very effective especially in adrenal lesions, addition of dual phase study routinely is not necessary and recommented in only indeterminated lesions.

PREDICTION OF PARANENDOPROSTHETIC COMPLICATIONS OF PATIENTS WITH THE PATHOLOGY OF HIP AND KNEE JOINTS OF VARIOUS GENESIS

Relevance. The issue of degenerative-dystrophic lesions of the hip and knee joints is becoming urgent in Ukraine. To date, in order to visualize degenerative-dystrophic and infectious-inflammatory lesions in the treatment and diagnostic process, the three-phase bone scintigraphy method is actively used, with the help of which it is possible to obtain a quantitative characteristic of metabolic changes and the morphological status of the organism.&#x0D; Objective. To determine the specific radionuclide parameters of three-phase bone scintigraphy for optimizing the prediction of paraendoprosthetic complications in pathological lesions of hip and knee joints of different genesis.&#x0D; Material and methods. The retrospective analysis of 455 patients with diseases of hip and knee joints of various genesis (including 274 women and 181 men), aged from 17 to 85 years, was conducted in the work. All patients underwent three-phase bone scintigraphy according to the standard protocol.&#x0D; Results. In the early static phase of bone scintigraphy, a gradual increase in the percentage of inclusion and distribution of radiopharmaceutical in degenerative-dystrophic and infectious-inflammatory foci is observed. The increase in accumulation of the indicator in the delayed static phase in the infectious-inflammatory foci of deforming osteoarthrosis is caused by an increase in the intensity of blood flow in the angiographic phase, which indicated the intensification of the arterial blood supply of such foci, due to active inflammation, exposure to an infectious agent or increased osteoblastic activity.&#x0D; Conclusion. The determination of the kinetic parameters of bone scintigraphy and the application of the radionuclide model of «dual time point imaging» contribute to the early detection of paraendoprosthetic complications in the postoperative period, the reduction of the number of revision procedures and the reduction in the duration of rehabilitation and recovery measures after endoprosthetics.

Kikuchi-Fujimoto disease with 18f-fludeoxyglucose uptake in cervical lymph nodes on dual-time-point imaging positron emission tomography/computed tomography mimicking malignant disease

Kikuchi-Fujimoto disease (KFD) is a benign but self-limiting disorder. However, KFD is often misdiagnosed as a malignant disease. Although 18F-fludeoxyglucose (FDG) uptake on dual-time-point imaging (DTPI) positron emission tomography (PET)/computed tomography (CT) is useful in distinguishing malignant from benign disease, the latter sometimes mimics malignancy on DTPI PET/CT, resulting in a misdiagnosis. Here, we describe the case of a 30-year-old woman who complained of cervical lymphadenopathy. PET showed increased FDG uptake in multiple lymph nodes, with a maximum standardized uptake value (SUVmax) of 19.0 in the early phase to 21.8 in the late phase. A biopsy was performed, and pathological examination revealed KFD. KFD with FDG uptake in lymph nodes on DTPI PET/CT is rare and difficult to be distinguished from a malignant disease.

18F-FDG PET/CT and sentinel lymph node biopsy in the staging of patients with cervical and endometrial cancer. Role of dual-time-point imaging

ObjectiveDefinitive staging for cervical (CC) and endometrial cancer (EC) takes place once surgery is performed. The aim of this study was to evaluate the role of PET/CT in detecting lymphatic metastasis in patients with CC and EC using dual-time-point imaging (DPI), taking the histopathological results of sentinel lymph node (SLN) and lymphadenectomy as the reference. Material and methodsA prospective study was conducted on 17 patients with early CC, and 13 patients with high-risk EC. The patients had a pre-operative PET/CT, MRI, SLN detection, and lymphadenectomy, when indicated. PET/CT findings were compared with histopathological results. ResultsIn the pathology study, 4 patients with CC and 4 patients with EC had lymphatic metastasis. PET/CT showed hypermetabolic nodes in 1 patient with CC, and 5 with EC. Four of these had metastasis, one detected in the SLN biopsy. Four patients who had negative PET/CT had micrometastasis in the SLN biopsy, 1 patient with additional lymph nodes involvement. The overall patient-based sensitivity, specificity, positive and negative predictive values, and accuracy of PET/CT to detect lymphatic metastasis was 20.0%, 100.0%, 100.0%, 87.9%, and 88.2%, respectively, in CC, and 57.1%, 88.9%, 66.7%, 84.2% and 80.0%, respectively, in EC. DPI showed higher retention index in malignant than in inflammatory nodes, although no statistically significant differences were found. ConclusionsPET/CT has low sensitivity in lymph node staging of CC and EC, owing to the lack of detection of micrometastasis. Thus, PET/CT cannot replace SLN biopsy. Although no statistically significant differences were found, DPI may help to differentiate between inflammatory and malignant nodes.

Dual time point method for the quantification of irreversible tracer kinetics: A reference tissue approach applied to [18F]-FDOPA brain PET

The Patlak graphical analysis (PGAREF) for quantification of irreversible tracer binding with a reference tissue model was approximated by a dual time point imaging approach (DTPREF). The DTPREF was applied to 18 [18F]-FDOPA brain scans using the occipital cortex as reference region (DTPOCC) and compared to both PGAOCC and striatal-to-occipital ratios (SOR). Pearson correlation analysis and Bland–Altman plots showed an excellent correlation and good agreement between DTPOCC and PGAOCC, while correlations between SOR and PGAOCC were consistently lower. Linear discriminant analysis (LDA) demonstrated a similar performance for all methods in differentiating patients with Parkinson’s disease (PD) from healthy controls (HC). Specifically for [18F]-FDOPA brain imaging, these findings validate DTPOCC as an approximation for PGAOCC, providing the same quantitative information while reducing the acquisition time to two short static scans. For PD patients, this approach can greatly improve patient comfort while reducing motion artifacts and increasing image quality. In general, DTPREF can improve the clinical applicability of tracers with irreversible binding characteristics when a reference tissue is available.