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

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

A Case of Primary Colon Carcinoma Demonstrated by FDG PET/CT Imaging After Detection of a Solitary Brain Metastasis

The detection of brain metastases as the initial manifestation of colorectal carcinoma without liver or lung involvement is extremely rare. Herein we present a case of a 52-year-old male patient with an unusual presentation of colon cancer, with primary lesions demonstrated by fluorine- 18-labeled fluorodeoxyglucose (FDG) Positron-emission tomography/computed tomography (PET/CT) after detection of a solitary brain metastasis. Brain CT images revealed a brain tumor. Histopathologic evaluation indicated metastatic poorly differentiated adenocarcinoma, while his physical examination was normal. The PET/CT revealed abnormal intense FDG uptake in the right parietal region and in descending colon, with no other abnormal FDG uptake elsewhere in the body. The histopathologic diagnosis of the descending colon lesion revealed moderately differentiated adenocarcinoma. This case indicates that FDG PET/CT imaging may have a positive impact on the evaluation of patients with brain metastasis from an unknown primary

Primary and Secondary Intracranial Hypotension: Clinical, MRI and Radioisotope Cisternography Findings

OBJECTIVE: It was aimed to evaluate the clinical features, magnetic resonance imaging (MRI) and radioisotope cisternography findings and results of the treatment in intracranial hypotension. METHODS: Fifteen patients diagnosed with intracranial hypotension were evaluated retrospectively. The opening pressure and analysis of cerebrospinal fluid (CSF), cerebral and spinal MRI and radioisotope cisternography findings, clinical features, and results of the treatment are discussed. RESULTS: The mean age of 15 patients, 11 women and 4 men, was 37 years. Eleven patients had spontaneous (primary) and 4 had secondary intracranial hypotension. Fourteen (93.3%) patients had orthostatic headache, and 1 (6.6%) patient’s headache did not have a postural feature. In addition to the headache, 5 (33.3%) patients had nausea and vomiting, 1 patient had diplopia, 1 had neck pain, and 1 had vertigo. Cerebral MRI revealed dural thickening in 12 (85.7%) patients, enlarged hypophysis in 5 (35.7%) patients, brain sagging in 3 (21.4%) patients, subdural hematoma in 2 (14.2%) patients, and subdural effusion in 2 (14.2%) patients. Spinal MRI was normal in 5 (83.3%) of 6 patients, and it showed meningeal thickening in 1 (16.6%). Radioisotope cisternography revealed CSF leak in 8 (88.8%) of 9 patients. CSF opening pressure was ≤ 60 mmH2O in 8 (88.8%) of 9 patients. CSF protein was increased in 3 patients. Complete improvement was obtained with conservative treatment in 8 (53.3%) patients. Seven (46.6%) patients who did not improve with conservative treatment were administered epidural blood patching, and 6 of these 7 patients improved completely. CONCLUSION: Orthostatic headache, low CSF opening pressure and characteristic MRI findings are essential criteria for diagnosis of intracranial hypotension. Radioisotope cisternography is useful to detect CSF leak. In patients who do not improve with conservative treatment, autologous blood patch should be applied

A Case of Inoperable Malignant Insulinoma with Resistant Hypoglycemia Who Experienced the Most Significant Clinical Improvement with Everolimus

Metastatic insulinomas may sometimes present with recurrent life-threatening hypoglycemia episodes. Such patients usually fail to respond to various therapeutic agents which causes constant dextrose infusion requirement. Herein, we present a resistant case of inoperable malignant insulinoma who was treated with many therapeutic agents and interventions including somatostatin analogues, Yttrium-90 radioembolization, everolimus, radiotherapy, and chemoembolization. Close blood sugar monitorization during these therapies showed the most favourable response with everolimus. Everolimus treatment resulted in rapid improvement of hypoglycemia episodes, letting us discontinue dextrose infusion and discharge the patient. However, experience with everolimus in such patients is still limited, and more precise data can be obtained with the increasing use of this agent for neuroendocrine tumours