Optimal activity of [18F]FDG for Hodgkin lymphoma imaging performed on PET/CT camera with BGO crystals.

BACKGROUND: We aimed to find the minimum feasible activity of fluorodeoxyglucose ([18F]FDG) in positron emission tomography/computed tomography (PET/CT) of Hodgkin lymphoma patients performed on a camera with bismuth germanate (BGO) crystals. MATERIAL AND METHODS: Ninety-one [18F]FDG PET/CT scans (each in seven Bayesian Penalized Likelihood [BPL] reconstructions with varying acquisition time per bed position - 2 min, 1.5 min, 1 min, 50 s, 40 s, 30 s, and 20 s) were independently assessed by three physicians to evaluate image quality. Mean administered activity was 3.0 ± 0.1 MBq/kg and mean uptake time was 54.0 ± 8.7 min. The series quality was subjectively marked on a 1-10 scale and then ranked 1-7 based on the mean mark. Interobserver rank correlation and intraclass correlation within each series for the three observers were calculated. Phantom studies were also performed to determine if reduced acquisition time can be directly translated into a reduced activity. RESULTS: Time series were marked and ranked unanimously - the longer the time of acquisition the higher the mark and rank. The interobserver agreement in the ranking was excellent (100%) with a kappa coefficient of 1.00 (95% CI [0.83-1.0]). The general intraclass correlation coefficient (agreement between the marks observers gave each time series) was very high (0.945, 95% CI [0.936-0.952]) and was higher the shorter the time per bed. According to all three observers only the series with 2 min and 1.5 min acquisition time were appropriate for assessment (mean mark ≥ 7). In phantom studies there was a linear correlation between time per bed, administered activity, and number of total prompts detected by a scanner. Hence, a reduction of acquisition time of 25% (from 2 min to 1.5 min) could be directly translated into a 25% activity reduction (from 3.0 to 2.25 MBq/kg). CONCLUSIONS: In patients with HL, [18F]FDG activity can be reduced by up to 25% when using a BGO crystal camera, without substantial impact on image quality.

CT imaging features of thin-walled cavitary squamous cell lung cancer.

Primary lung cancer manifesting as a thin-walled solitary cavity, occurs relatively infrequently. The most common histologic type presenting such a pattern is squamous cell cancer, followed by adenocarcinoma, and finally - large cell cancer. Cavitation is typically not seen in small cell lung cancer. Entities indicating malignancy of such lesions include irregular cystic wall, wall nodule formation, nodular septa or increased standard uptake on positron emission tomography (PET). We are presenting a case of a squamous cell lung cancer manifesting on chest CT as a thin-walled septated cavity with irregular margins mimicking a cyst. The lesion was reported unchanged in a follow-up computed tomography after 3 months. A follow-up scan obtained 2 years after initial examination showed thickening of a cyst wall, solid structures within its lumen and thoracic lymph nodes enlargement.

Hounsfield units from unenhanced 18F-FDG-PET/CT are useful in evaluating supradiaphragmatic lymph nodes in children and adolescents with classical Hodgkin's lymphoma.

BACKGROUND: The precise identification of the primarily-affected nodal regions in Hodgkin's lymphoma(HL) is essential in determining the stage of the disease and the intensity of chemotherapy and radiotherapy. OBJECTIVES: The aim of this study was to use the degree of X-ray attenuation (XRA) in Hounsfield units(HU) and the lymph node-to-muscle attenuation ratio (LN/M) in computed tomography (CT) unenhancedimaging, routinely performed with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET),to distinguish HL-affected supradiaphragmatic lymph nodes. MATERIAL AND METHODS: The study included 52 patients with classical HL treated according to the EuroNet-PHL-C1 protocol. Patients received 2 chemotherapy cycles after 18F-FDG-PET/CT testing, followedby re-examination. The lymph nodes were evaluated according to the Society for Pediatric Oncology andHematology's GPOH-HD-2002 study and Lugano criteria as not-involved (NI-LN) and involved (I-LN). RESULTS: A significant difference (p < 0.001) was found in the XRA and LN/M values between NI-LN andI-LN before treatment and after the 2 chemotherapy cycles. The optimal cut-off point for XRA (44.7 HU) andLN/M (0.79) values distinguishing I-LN from NI-LN nodes was determined by receiver operating characteristic(ROC) analysis. After 2 cycles of chemotherapy, higher XRA (p = 0.002) and LN/M (p = 0.001) values in thegroup with inadequate early CTx response were found. CONCLUSIONS: The use of XRA in HU and LN/M, together with the existing standard, can improve the qualificationof supradiaphragmatic lymph nodes in HL.

Ectopic Cushing's syndrome in light of modern diagnostic techniques and treatment options.

Ectopic adrenocorticotropic hormone secretion (EAS) is responsible for approximately 10-15% cases of Cushing's syndrome. EAS is associated with various tumors such as small cell lung cancer and well-differentiated bronchial or gastrointestinal neuroendocrine tumors. Hormonal diagnostics include assessments in basic conditions as well as dynamic tests, such as the high-dose dexamethasone suppression test and corticotrophin releasing hormone (CRH) stimulation test. Treatment selection depends on the type of tumor and its extent. In the case of neuroendocrine tumors, the main treatments are surgery and administration of somatostatin analogs that may be additionally radiolabeled for targeted radiotherapy. The tumor histology and the presence and control of hypercortisolemia and metastases are of major importance in prognosis. In this article we presented the principles of modern hormonal and imaging diagnostics techniques as well as the key issues associated with treatment of ACTH-dependent Cushing's syndrome due to EAS.

Accuracy of FDG PET/CT in the evaluation of solitary pulmonary lesions - own experience.

INTRODUCTION: In recent years, positron emission tomography (PET) has been increasingly applied in the diagnosis of neoplastic lung diseases. In contrast to conventional imaging studies, PET-CT enables the visualisation of not only the morphology of the suspicious lesion, but also its metabolism. The aim of the present study was to investigate the role of PET-CT in the initial assessment of patients with indeterminate solitary pulmonary lesions. MATERIAL AND METHODS: The study was conducted on a group of 82 patients with indeterminate lung nodule diagnosed at the National Institute of Tuberculosis and Lung Diseases in the period from January 2008 to May 2011. CT and PET-CT were performed in all of the patients. Histological or cytological examination of the biopsy specimens obtained from bronchoscopy, mediastinoscopy and intraoperatively were the reference tests. RESULTS: Malignancy was documented in 40 patients (48.8%). Histopathological analysis of all tumours revealed 12 cases of squamous cell carcinoma, 18 cases of adenocarcinoma and 1 case of carcinoid, whereas in 9 patients the diagnosis of "non-small cell cancer not otherwise specified" was made. All lesions except one were of solid character on chest CT. SUV(max) values exceeding 2.5 were found in 38 cancer patients (true positives, TP). The mean value of SUV(max) was 9.1 (1-26.8). Forty-two lesions were documented as benign (51.2%). SUV(max) values equal to or less than 2.5 were found in 37 patients (true negatives, TN). The mean value of SUV(max) in this group was 1.9 (0.5-8.6). The diagnostic value of PET-CT SUV(max) exceeding 2.5 in the prediction of neoplastic origin of solitary pulmonary lesions was: sensitivity - 95% (95% CI 84-99%), specificity - 88% (95% CI 75-95%) and accuracy - 91.5% (95% CI 83-96%). Positive predictive value (PPV) was 88.4% (95% CI 76-95%), and negative predictive value (NPV) was 94.8% (95% CI 83-99%). False negative results concerned two patients, with final diagnosis of carcinoid and adenocarcinoma; false positive results were obtained in 5 patients with various inflammatory lesions. CONCLUSIONS: In the present study, PET-CT appeared to have high sensitivity (95%), but lower specificity (88%) for predicting the malignant character of solitary pulmonary lesions. Overall diagnostic value of PET-CT SUV(max) > 2.5 was high - PPV was 88.4%, NPV was 94.8%. In the authors' opinion, the PET-CT value may increase when clinical data as well as other radiological documentation (with retrospective assessment) are taken into consideration.

Assessment of recurrence of non-small cell lung cancer after therapy using CT and Integrated PET/CT.

INTRODUCTION: Non-small cell lung cancer (NSCLC) has become the leading cause of cancer-related deaths in Poland. Follow-up of patients with NSCLC is aimed at early detection of local recurrence, metastatic process, treatment-related complications or second primary lung cancer. We investigated the diagnostic accuracy of FDG-PET-CT in the detection of recurrence of NSCLC after treatment. MATERIAL AND METHODS: Seventy-two NSCLC patients (19 females, 56 males), stage I to IV, who had undergone surgery and/ /or radiation therapy, occasionally associated with chemotherapy, were retrospectively included in our study. Chest radiographs and thoracic computed tomography (CT) were performed to localize the abnormality prior to PET-CT. All the patients underwent CT and PET-CT in the period from January 2008 until January 2012. All PET images were interpreted in conjunction with thoracic CT. PET-CT and CT diagnoses were correlated with pathological diagnoses. RESULTS: Forty-five patients had recurrent tumour. Tumour recurrence was observed more often in men than in women and also in case of neoplastic cell emboli in lymphatic or blood vessels. In three patients second primary lung cancer was diagnosed. False positive diagnosis of relapse based on PET-CT was obtained in 4 patients, mainly due to inflammatory lesions. The accuracy of PET-CT for diagnosis of recurrence was 94.4% (95% CI 91; 100). CONCLUSIONS: FDG PET-CT was the best method to differentiate recurrent bronchogenic carcinoma from inflammatory lesions, especially at post-therapeutic sites. It has been shown that PET-CT is more accurate method than CT in recurrent NSCLC. PET-CT results had a further impact on the clinical management and treatment planning.

[Staging of non-small cell lung cancer using CT and integrated PET-CT]. / Ocena zaawansowania niedrobnokomórkowego raka pluca metodatomografii komputerowej i pozytonowej tomografii emisyjnejskojarzonej z tomografia komputerowa

INTRODUCTION: Lung cancer is the leading cause of death from cancer in developed countries. Radiological imaging methods are the basic methods in early diagnosis of this disease. TNM classification is a very important tool for optimal treatment in non-small lung cancer (NSCLC). Conventional radiological techniques allow the evaluation of the stage on the basis of anatomical changes only, while PET-CT provides information about the biochemical processes that may precede anatomical changes. The aim of this study was to compare the accuracy and sensitivity of CT and PET-CT in the staging of NSCLC. MATERIAL AND METHODS: The study was conducted on a group of 99 patients with NSCLC diagnosed at the Institute of Tuberculosis and Lung Diseases in the period from January 2008 to May 2010. CT and PET-CT were performed in all patients. Histological or cytological examination of the material obtained from biopsy, bronchoscopy, mediastinoscopy, and intraoperatively was the reference test. TNM classification was performed independently after CT and PET-CT. RESULTS AND CONCLUSIONS: It has been shown that PET-CT is a more accurate and sensitive method than CT in the staging process in NSCLC. PET-CT allowed the correct classification of the T, N, M, and total TNM in, respectively, 97%, 95%, 99%, and 89% of cases, while for CT it was, respectively, 95%, 84%, 84%, and 68% (p = 0.0002).

Prospective echocardiographic evaluation of patients with endogenous subclinical hyperthyroidism and after restoring euthyroidism.

OBJECTIVES: Clinical significance of, and the need for, treatment in subclinical hyperthyroidism (sHT) is still a matter of debate. The aim of the study was to assess the impact of sHT on echocardiographic parameters. DESIGN: Patients with endogenous sHT of nonautoimmune origin underwent full echocardiographic assessment at diagnosis and after restoring euthyroidism with radioiodine treatment. PATIENTS: Studied group consisted of 44 patients (37 women, 7 men), aged 22-65 years (mean 45·9±11·0). MEASUREMENTS: Full echocardiographic assessment included estimation of cardiac chamber diameters and volume as well as cardiac contractility, according to the guidelines of the American Society of Echocardiography. Left ventricular mass was calculated according to Penn's convention. For estimation of left ventricle diastolic function, the following echocardiographic parameters were obtained: maximal early filling wave velocity (E), maximal late filling wave velocity (A), E/A ratio, isovolumetric relaxation time and early filling wave deceleration time. RESULTS: In the studied group, phase of sHT was associated with increased volume of heart chambers, increased diameter of ascending aorta, increased left ventricle mass and disturbed left ventricle relaxation (P<0·05). The systolic function of the left ventricle was unaffected; however, the ejection time was shortened. The changes were reversible with restoring biochemical euthyroidism (P<0·05). Moreover, a significant correlation between some of the parameters and thyroid hormones concentration was demonstrated. CONCLUSIONS: sHT was associated with significant changes in echocardiographic parameters, which may contribute to increased cardiovascular risk in these patients. The alterations were reversible with restoring biochemical euthyroidism, what supports the necessity of treatment introduction in sHT.