Kuan-Yin Ko

Intratumoral Heterogeneity of Pretreatment 18F-FDG PET Images Predict Disease Progression in Patients With Nasal Type Extranodal Natural Killer/T-cell Lymphoma.

Purpose The aim of this study was to investigate whether the textural features of pretreatment 18F-FDG PET images can predict prognosis for nasal type extranodal natural killer/T-cell lymphoma (ENKTL). Materials and Methods A retrospective analysis of the pretreatment 18F-FDG PET images of the patients with newly diagnosed nasal type ENKTL from 2008 to 2013 was conducted. Progression-free survival (PFS) was the main outcome measure. The primary tumor was identified and then delineated using the 40% maximum standardized uptake value (SUVmax) thresholding method. The textural features of the pretreatment 18F-FDG PET images were extracted. The prognostic significance of the textural features of the PET images were examined using the receiver operating characteristic (ROC) curves and Cox regression analysis. P values <0.05 were considered statistically significant. Results In total, 17 patients were enrolled, among whom 11 showed disease progression and 6 died from the disease during the median follow-up period of 27.2 months. Dissimilarity and low-intensity short-zone emphasis (LISZE) were identified as independent predictors of PFS by using the ROC curves and multivariate Cox analysis after adjusting for the clinical variables. Conclusions Dissimilarity and LISZE were the significant predictors of disease progression in patients with nasal type ENKTL and can improve their prognostic stratification.

Incremental Diagnostic Performance of Combined Parameters in the Detection of Severe Coronary Artery Disease Using Exercise Gated Myocardial Perfusion Imaging

Purpose Myocardial perfusion imaging (MPI) using gated single-photon emission tomography (gSPECT) may underestimate the severity of coronary artery disease (CAD). This study aimed to evaluate the significance of combined parameters derived from gSPECT, as well as treadmill stress test parameters, in the detection of severe CAD. Methods A total of 211 consecutive patients referred for exercise MPI between June 2011 and June 2013 (who received invasive coronary angiography within six months after MPI) were retrospectively reviewed. Exercise MPI was performed with Bruce protocol and 201Tl injected at peak exercise. Gated SPECT was performed using a cadmium-zinc-telluride camera and processed by QPS/QGS software. Perfusion defect abnormalities such as sum stress score (SSS); sum difference score, algorithm-derived total perfusion deficits, transient ischemic dilatation ratios of end-diastolic volumes and end-systolic volumes, post-stress changes in ejection fraction, and lung/heart ratio (LHR) were calculated. Treadmill parameters, including ST depression (STD) at the 1st and 3rd minutes of recovery stage (1’STD and 3’STD), maximal STD corrected by heart rate increment (ST/HR), heart rate decline in 1st and 3rd minutes of recovery stage, recovery heart rate ratio (HR ratio), systolic and mean blood pressure ratios (SBP ratio and MAP ratio) during recovery phase were recorded. Diagnostic performances of these parameters were analyzed with receiver operating characteristic (ROC) analysis and logistic regression for detection of left main (≥ 50%) or 3-vessel disease (all ≥ 70% luminal stenosis) on invasive angiography. Results Among various MPI and treadmill parameters used for detection of severe CAD, SSS and ST/HR had the highest AUC (0.78, 0.73, p = NS) and best cut-off values (SSS > 6, ST/HR > 17.39 10-2mV/bpm), respectively. By univariate logistic regression, all parameters except 1’HRR, 3’HRR, SBP and MAP ratios increased the odds ratio of severe CAD. Only increased L/H ratio, 3’STD, and HR ratio remained significant after multivariate regression. The predicted values of combined MPI and treadmill parameters (LHR, 3’STD, and HR ratio) gave the best ROC (AUC: 0.91) than any individual parameter or parameter combination. Conclusions Of all treadmill and gSPECT parameters, the combination of MPI and treadmill parameters can offer better diagnostic performance for severe CAD.

18F-NaF PET/CT Images of Cardiac Metastasis From Osteosarcoma.

Osteosarcomas are aggressive with a high incidence of recurrence and metastasis. Cardiac osteosarcoma metastasis is rare. We described a 17-year-old boy who had right distal femoral osteosarcoma with lung metastases. During follow-up, right ventricular (RV) metastasis was noted and confirmed by histopathological examination of the surgical specimen. F-NaF PET/CT was then arranged 1 month after debulking surgery for residual tumor survey. The images showed intense F-NaF uptake at RV region, suggestive of residual cardiac metastases.

Clinical significance of right ventricular activity on treadmill thallium-201 myocardial single-photon emission computerized tomography using cadmium-zinc-telluride cameras.

ObjectiveIdentification of right ventricular (RV) abnormalities is important in patients with suspected coronary artery disease (CAD). RV activity can be better visualized on myocardial single-photon emission computerized tomography (SPECT) using a higher sensitivity cadmium–zinc–telluride (CZT) detector. The aim of this study was to investigate the clinical significance of RV/left ventricular (LV) uptake ratios during exercise thallium-201 SPECT using CZT detectors. Patients and methodsA total of 102 patients underwent treadmill ECG-gated SPECT, coronary angiography, and echocardiography. SPECT myocardial perfusion was interpreted using a 17-segment model and a 0–4-point scale. RV/LV uptake ratios were calculated on the basis of maximum counts per pixel within the entire RV and LV walls. The relationships between RV/LV uptake ratio and gated SPECT, presence of CAD (≥50% stenosis in the left main or ≥70% in the main branches), demographics, and echocardiographic parameters were analyzed. ResultsStress RV/LV ratios correlated positively with the presence of left main or multivessel disease, and tricuspid regurgitation maximum pressure gradient. After multivariate regression, stress/rest RV/LV ratios correlated positively with mitral flow deceleration time, age, female sex, and use of &bgr;-blockers. ConclusionRV/LV uptake ratios on the basis of exercise myocardial perfusion SPECT imaging using CZT cameras are useful for the detection of severe CAD and could serve as an indicator of pulmonary hypertension and LV diastolic dysfunction.

Pregnancy Outcome After I-131 Therapy for Patients With Thyroid Cancer: A Nationwide Population-Based Cohort Study.

Abstract The aim of this study was to evaluate the influence of I-131 therapy on pregnancy outcome in patients that received therapeutic I-131 doses for thyroid cancer in Taiwan. This nationwide population-based cohort study was based on data from 1998 to 2010 obtained from the Taiwanese National Health Insurance Research Database. We identified 11,708 women with thyroid cancer (≥15 and ⩽50 years of age) by International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients were divided into 2 cohorts: I-131 therapy cohort and non-I-131 therapy cohort. The mean follow-up period was 6.08 years for the I-131 cohort and 6.87 years for the non-I-131 cohort. The case cohort and the control cohort comprised 775 and 716 pregnant patients, respectively. The overall incidence of pregnancy was significantly lower in the I-131 cohort (adjusted HR = 0.77, 95% CI = 0.70–0.86) and it was also observed when the patients were stratified according to age (HR = 0.73, 95% CI = 0.64–0.83 in 25–34 years; HR = 0.63, 95% CI = 0.49–0.82 in 35–44 years). Patients in the I-131 cohort had a lower successful delivery rate, particularly among patients in 25 to 34 years (OR = 0.60, 95% CI = 0.45–0.80). No significant difference was observed for adverse pregnancy conditions between 2 cohorts. I-131 therapy is associated with decreased pregnancy and successful delivery rates. The underlying mechanism likely involves physician recommendation, patients psychological issue, and potential impact of I-131 treatment on reproductive health. Further investigation is needed.

Ictal Phase Perfusion SPECT of Nonketotic Hyperglycemia-Induced Parieto-occipital Seizure.

A 68-year-old man with diabetes mellitus type 2 presented himself with visual distortion and apraxia. Nonketotic hyperglycemic seizure with both motor and sensory components was suspected. Tc-ECD perfusion SPECT demonstrated hyperperfusion at right parieto-occipital lobe during ictal phase. Normalization of hyperperfused area was noted on follow-up perfusion SPECT after intense glucose control. In nonketotic hyperglycemic state, the depletion of GABA in cerebral neurons lowers the seizure threshold. We demonstrated that ictal phase perfusion SPECT contributed to not only diagnosis but also served as a follow-up tool.

The clinical significance of right ventricular activity on Tl-201 myocardial SPECT using CZT cameras

Following the path of clinical applications of hybrid PET/CT, it would seem logical that PET/MR imaging can provide an innovative and attractive alternative taking full advantage of the superiority of MR imaging over CT in differentiating soft-tissue characteristics with a reduction of radiation exposure. The challenges of PET/MR imaging are still numerous both on the technical side and on the clinical side. Atlas of PET/MR Imaging in Oncology, edited by internationally known experts in the fields of PET and MR imaging, highlights the potential applications of whole-body hybrid PET/MR imaging in oncology. Although it is a convincing collection of anecdotal cases, it reflects only the early observations of 2 academic centers that were first adopting this new technique in clinical practice. The book is divided into 2 parts, with the first part consisting of 3 chapters that introduce hybrid imaging, PET/MR instrumentation, and technical principles and cover the protocols for standard PET/MR imaging acquisition. The second part has 9 chapters illustrating head and neck, prostate, breast, and gynecologic cancers; brain tumors; pediatric oncology; lymphomas; endocrine tumors; and degenerative and inflammatory diseases. Each case study includes a brief introduction, clinical history, imaging findings, and teaching points, followed by comments. The images are of good quality, and the references are updated. The multimedia version of the book also includes dynamic movies that allow the reader to browse through series of rotating 3-dimensional images, display blending between PET and MR imaging, and visualize 3-dimensional image volumes. The movies can be played either continuously or sequentially for better exploration of sets of images. The diversity of cases and broad scope of clinical domains covered in the different chapters underline the potential applications not only in oncology but also in other clinical domains. The use of different radiolabeled tracers such as 18F-fluorocholine and 18F-fluorotyrosine also shows the potential of PET beyond the conventional 18F-FDG tracer in clinical applications of hybrid PET/MR imaging. This new imaging modality has only recently been introduced for clinical use and will face the same challenges and skepticism that PET/CT encountered. The lack of a tangible added value from combined PET/MR imaging over the two examinations acquired separately is the first issue that needs to be addressed from both a clinical perspective and a cost-effectiveness point of view. This is the first book on PET/MR imaging in oncology. I highly recommend it to trainees and practitioners in the fields of nuclear medicine and radiology, as well as oncology.