Comparison of standardized uptake values obtained from two- and three-dimensional modes of fluorine-18 fluorodeoxyglucose PET-CT in oncological cases

PURPOSEWe investigated the usability of standardized uptake values (SUV) obtained from both two- and three-dimensional (2D and 3D) positron-emission tomography and computed tomography (PET-CT) imaging, and compared the images obtained from these techniques in terms of image quality, lesion detectability, and the presence of artifacts. MATERIALS AND METHODSImage data from 100 patients, who had undergone two PET imagings obtained in 2D and 3D mode after a low dose CT, were evaluated prospectively. Subjective analysis of 2D and 3D images was performed by two readers evaluating the following criteria: overall image quality, detectability of each identified lesion, and the presence of artifacts. The lesions recognized by the readers were also analyzed quantitatively by measuring SUV values. RESULTSThere was a significant difference between the SUVs obtained in 2D and 3D modes. Regardless if the first scan was performed in 2D or 3D mode, the values obtained from 3D imaging were significantly lower than those obtained from 2D imaging (mean SUVmax was 10.48±7.57 for 2D, and 9.66±6.93 for 3D, P < 0.001). Visual analysis did not reveal significant differences regarding lesion detectability between two modes. CONCLUSIONIn oncological PET-CT applications, SUV values are significantly lower in 3D compared with 2D mode. Thus when serial scanning is needed to evaluate response to therapy in the same patient, the imaging modality should be taken into account and performed with the same method to avoid misinterpretation. Additionally, 3D PET-CT imaging can be used instead of 2D PET-CT due to its shorter scanning time without loss of lesion detectability

Comparison of CT and PET-CT based planning of radiation therapy in locally advanced pancreatic carcinoma

Abstract Background To compare computed tomography (CT) with co-registered positron emission tomography-computed tomography (PET-CT) as the basis for delineating gross tumor volume (GTV) in unresectable, locally advanced pancreatic carcinoma (LAPC). Methods Fourteen patients with unresectable LAPC had both CT and PET images acquired. For each patient, two three-dimensional conformal plans were made using the CT and PET-CT fusion data sets. We analyzed differences in treatment plans and doses of radiation to primary tumors and critical organs. Results Changes in GTV delineation were necessary in 5 patients based on PET-CT information. In these patients, the average increase in GTV was 29.7%, due to the incorporation of additional lymph node metastases and extension of the primary tumor beyond that defined by CT. For all patients, the GTVCT versus GTVPET-CT was 92.5 ± 32.3 cm3 versus 104.5 ± 32.6 cm3 (p = 0.009). Toxicity analysis revealed no clinically significant differences between two plans with regard to doses to critical organs. Conclusion Co-registration of PET and CT information in unresectable LAPC may improve the delineation of GTV and theoretically reduce the likelihood of geographic misses.</p

Hepatobiliary scintigraphy to detect duodenogastric reflux: Intravenous administration of Tc-99m pertechnetate to define the location of the stomach

PubMedID: 11290908A 65-year-old man who had a cholecystectomy 20 years previously and a recent 6-month history of right upper abdominal pain that spread to the back was evaluated for duodenogastric reflux by hepatobiliary scintigraphy. Abnormal activity in two frames suggested duodenogastric reflux. To determine file location of the stomach, intravenous administration of Tc-99m pertechnetate was administered after the hepatobiliary scan. This is a simple method that includes only the intravenous administration of 3 to 5 mCi (111 MBq) Tc-99m pertechnetate and is a good alternative to the oral use of technetium agents, which have a carefully calculated dose adjustment to avoid scatter, and dual-isotope imaging, which requires a second isotope

The value of F-18-fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of an unknown primary: diagnosis and follow-up

WOS: 000272915000010PubMed ID: 19952921Background The management of the patients with carcinoma of an unknown primary represents a difficult challenge in oncology. F-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has provided new insights in the diagnosis, staging, and follow-up of oncological patients. Aim This study aimed to investigate the value of FDG PET/CT in clarifying the primary site in our patients with histologically proven tumor metastasis (HPM) or with a high clinical suspicion of malignancy, and the clinical impact of this technique on the management of these patients. Methods In total 94 patients from two centers underwent FDG PET/CT imaging; 78 patients with HPIVI and 16 patients with a clinical suspicion of malignancy. The histology and/or follow-up data were used as the gold standard. Hypermetabolic findings at the site of the pathological CT changes or at physiological FDG uptake sites were the criteria for malignancy. PET/CT findings were analyzed for the identification of the primary tumor site, for the relationship with survival, and also for the effect in chemotherapy monitoring. Results Primary malignancy was discovered in 53 of 90 patients (59%) histologically and 37 (41%) patients' primary tumor sites were not found during the study period. Amongst 90 patients, five (6%) were normal on FDG PET/CT. Of 85 patients (94%) with pathological findings on FDG PET/CT, 27 patients (32%) had solitary and 58 (68%) patients had multiple organs affected. Regarding the whole study population, a sensitivity of 74% and a specificity of 78% were calculated for FDG PET/CT imaging. Regarding the patients with HPM, the sensitivity and specificity values were 84 and 81%, respectively. The mean survival time of the patients with disseminated disease was significantly shorter than those of the patients with single or no lesion (13.44 +/- 1.61, 20.98 +/- 2.0 and 26.67 +/- 2.73 months, respectively, P = 0.014). In seven of eight patients, follow-up FDG PET/CT scans effectively monitored the patients' therapies. Conclusion Whole-body FDG PET/CT has to be considered a useful method, especially in an early phase of the diagnostic workup of patients with carcinoma of an unknown primary syndrome, to optimize the management. Nucl Med Commun 31:59-66 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

Venous thrombosis of sarcoidosis as an unusual incidental finding on 18F-fluorodeoxyglucose positron emission tomography/computed tomography

Sarcoidosis is defined as a multisystem granulomatous disorder of unknown cause. Venous thrombosis (VT) in the sarcoidosis is rare. The routine use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has resulted in clinicians detecting many incidental findings, which have proven to be clinically significant such as thrombosis. Here, we present a case with VT of sarcoidosis in the inferior vena cava and portal vein as an unusual incidental finding on 18F-FDG PET/CT

Stabil anjina pektoris’li hastaların değerlendirilmesinde dobutamin stres doku Doppler görüntüleme ve miyokardiyal perfüzyon SPECT

To evaluate longitudinal function of ischemic and nonischemic myocardial tissue detected by Tc-99m MIBI single photon emission computed tomography (SPECT) prior to coronary revascularization in patients with stable angina pectoris. Methods: We studied 24 consecutive patients (mean age 62&plusmn;9 years; 5 women) with stable angina pectoris. All patients underwent myocardial perfusion SPECT. Tissue Doppler imaging (TDI) was performed to detect myocardial systolic velocities of anterior, inferior, septum and lateral walls at rest and peak dobutamine stress. Results: A total of 96 segments were visualized with SPECT study. Maximum mean septal, lateral, anterior and inferior TDI systolic velocities were similar in ischemic and nonischemic segments (6.73&plusmn;1.04 cm/sec, 6.93&plusmn;1.34 cm/sec, respectively) at rest. At peak stress, maximum mean TDI systolic velocities were lower in the 37 ischemic segments (11.00&plusmn;2.03 cm/sec) than 59 nonischemic segments (13.76&plusmn;1.97cm/sec, p &lt; 0.001). Because we detected ischemia in whole group using both diagnostic tests, coronary angiography was decided. Critical coronary artery stenosis related to ischemic segments was detected and coronary revascularization decided. Conclusion: TDI with dobutamine stress can be used in patients with stable angina pectoris. In this study, we observed that quantitative data by TDI associated with SPECT showed an agreement for coronary revascularization.Koroner revaskülarizasyon öncesi stabil anjina pektorisli hastalarda Tc-99m MIBI SPECT ile saptanan iskemik ve normal miyokardiyal dokunun longitüdinal fonksiyonunu değerlendirmektir. Yöntemler: Stabil anjina pektoris’li 24 ardışık hasta çalışmaya dahil edildi (ortalama yaş 62±9 yıl; 5 kadın). Tüm hastalara miyokardiyal perfüzyon SPECT sintigrafisi yapıldı. İstirahatta ve zirve dobutamin streste ön, alt, septum ve yan duvarların doku Doppler görüntüleme (DDG) ile miyokardiyal sistolik hızları tespit edildi. Bulgular: SPECT çalışmasında toplam 96 segment görüntülendi. İstirahatta ortalama en yüksek septal, yan, ön ve aşağı duvar DDG sistolik hızları iskemik olan ve iskemik olmayan segmentlerde benzerdi (sırasıyla 6.73±1.04 cm/sn, 6.93±1.34 cm/sn). Zirve streste, ortalama en yüksek DDG sistolik hızları 37 iskemik segmentte (11.00±2.03 cm/sn), 59 iskemik olmayan segmente (13.76±1.97cm/sn, p < 0.001) göre daha düşüktü. Her iki tanı testi ile tüm hasta grubunda iskemi tespit etmemiz nedeniyle tüm vakalara koroner anjiografi uygulandı ve iskemik segmentlerle ilişkili kritik koroner arter darlıkları saptandı. Sonuç: Anlamlı koroner arter darlıkların saptanmasında DDG yöntemi SPECT ile uyumlu olarak ek bilgi sağlayabilir