Accuracy of FDG-PET/CT and paraneoplastic antibodies in diagnosing cancer in paraneoplastic neurological syndromes.

OBJECTIVE: There is still no consensus about whether to perform PET/CT to detect carcinoma in paraneoplastic neurological syndromes (PNS) in patients with or without antibodies. The aim of this study is to determine the diagnostic accuracy of PET/CT and antibodies in patients with PNS. MATERIAL AND METHODS: A retrospective study was conducted on patients with clinically suspected PNS between 2008 and 2013. The association between histopathological findings, paraneoplastic antibodies, and PET/CT findings were evaluated. Sensitivity and specificity for the detection of underlying malignancy were calculated for PET/CT and paraneoplastic antibodies. RESULTS: A total of 42 patients were analyzed. Of these 42 patients, 32 (75%) had a classical PNS, 6 (14%) had positive PET/CT findings, and 34 were tested for the presence of antibodies (anti-Hu Ab, anti-Yo Ab, and anti-Ri Ab). Twenty one of 34 patients had positive antibodies. Of the 6 patients with positive PET/CT findings, 6 had positive histopathological results. Among 21 patients with positive biomarkers, carcinoma was confirmed only in 5 patients. One patient with negative antibodies, but positive PET/CT findings, was diagnosed with a tumor. Gastric carcinoma was detected in 1 patient with negative PET/CT findings and antibodies during follow-up. Based on the results, PET/CT was found to have 85.71% sensitivity, 100% specificity, 100% positive and 97.22% negative predictive values in the detection of tumors. CONCLUSION: PET/CT has a certain diagnostic accuracy for detecting underlying malignancy in patients with PNS, regardless of the presence of paraneoplastic antibodies.

Decreased preoperative serum fibulin-3 levels in colon cancer patients.

OBJECTIVE: Fibulin-3 is known to play a role in tumor cell malignancy, invasion and metastasis, as well as in the clinical progression of tumors. This study aimed to assess serum fibulin-3 levels in patients with colon cancer compared with healthy controls and its relationship to demographics and tumor pathology. PATIENTS AND METHODS: A total of 80 patients (mean age, 58.99 years; 42% males) with colon cancer and 50 controls (mean age, 57.75; 55% males) were included. Serum levels of fibulin-3 were determined using a commercially available sandwich ELISA (Enzyme-Linked ImmunoSorbent Assay). RESULTS: Preoperative serum fibulin-3 levels were significantly lower in the group of patients with colon cancer (mean, 35.91 ng/mL; range, 10-73 ng/mL) compared with the control group (mean, 96.68 ng/mL; range, 57-168 ng/mL). CONCLUSIONS: It was concluded that fibulin-3 is expressed at a lower level in colon cancer, and it can serve as a marker for advanced colon cancer.

Comparison of FDG and FDG-labeled leukocytes PET/CT in diagnosis of infection.

UNLABELLED: The aim of this study is to compare FDG and FDG-labeled leukocyte (WBC) PET/CT in the diagnosis of infection using different SUV and visual thresholds for interpretation. Patients, material, method: 49 consecutive patients (27 men, 22 women, mean age: 55.7 years, range: 16-89 years) with suspected musculoskeletal infection (n = 34), vascular graft infection (n = 5), aortitis (n =1 ), endocarditis (n = 1), mass lesion which is suspicious for infection or malignity (n = 6), and fever of unknown origin (n = 2) underwent both FDG and WBC-PET/CT. Images were evaluated by both visual analysis (grade 1-3) according to uptake intensity and quantitative grading (grade 1-3) based on lesion to background SUVmax values. Final diagnosis was made by histopathological, microbiological analysis or clinical-radiological work-up. RESULTS: The diagnosis of infection was made in total 24 patients, of whom 14 were diagnosed by histopathological and the rest by clinical-radiological work-up. WBC-PET/CT imaging with the visual threshold of 1b as infection positivity (for truncal lesions uptake equivalent to liver or lumbar vertebrae uptake; for extremity lesions uptake significantly higher than neighbouring soft tissue uptake or higher than neighbouring bone marrow uptake) was found to have the highest diagnostic accuracy (AUC: 0.874, CI: 0.771-0.997, p < 0.001). The optimal SUV threshold was found to be 8.8 (p = 0.006; sensitivity: 72.7%, specificity: 82.8) and 5.3 (p < 0.001; sensitivity: 81.8%, specificity: 79.3%) for FDG and WBC-PET/CT, respectively by ROC curve analysis. CONCLUSION: WBC-PET/CT is more valuable than FDG PET/CT in the imaging of infection. Visual threshold of >1b seems to be more suitable for detection of infection.

FDG PET/CT in monitoring treatment of retroperitoneal fibrosis.

Retroperitoneal fibrosis is an uncommon disease characterized by inflammatory fibrosis typically surrounding abdominal aorta and iliac arteries. The glucose analogue F18-fluorodeoxyglucose can be used to image inflammatory cell activity non-invasively by PET. In this report we investigated the usefulness of the FDG PET/CT in the disease activity and therapy response evaluation of retroperitoneal fibrosis.

Radio-guided occult lesion localisation for breast lesions under computer-aided MRI guidance: the first experience and initial results.

OBJECTIVE: The purpose of this study was to present an alternative technique for the pre-operative localisation of solely MRI-detected suspicious breast lesions using a computer-assisted MRI-guided radio-guided occult lesion localisation (ROLL) technique. METHODS: Between January 2009 and June 2010, 25 females with a total of 25 suspicious breast lesions that could be detected only by MRI, and for whom breast surgery was planned, underwent the computer-assisted MRI-guided ROLL technique. A seven-channel biopsy breast array coil and computerised diagnostic workstation were used for the localisation procedure. Three-phase dynamic contrast-enhanced axial images were taken. After investigating the localisation co-ordinates with the help of intervention software on a workstation, an 18 G coaxial cannula was placed in the exact position determined. Following verification of the cannula position by additional axial scans, (99m)Tc-labelled macroalbumin aggregate and MRI contrast material were injected. Post-procedure MRI scans were used to confirm the correct localisation. RESULTS: All the procedures were technically successful. The mean lesion size was 10.8 mm (range: 4-25 mm). The mean total magnet and the mean localisation times were 28.6 min (range: 18-46 min) and 13.1 min (range: 8-20 min), respectively. Grid and pillar methods were used for localisation in 24 procedures and 1 procedure, respectively. On histopathological examination, 6 malignant, 10 high-risk and 9 benign lesions were identified. All patients tolerated the procedure well. There were no major complications. CONCLUSION: This is the first report documenting the application of MRI-guided ROLL. Based on our preliminary results, this technique is very efficient and seems to be a good alternative to wire localisation.

Detection of metastases in patients with cutaneous melanoma using FDG-PET/CT.

This study aimed to detect metastases in patients with stage III or IV cutaneous melanoma by (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT). Thirty-nine patients with clinically evident stage III or IV melanoma underwent whole-body FDG-PET/CT scans for metastatic disease and these results were compared with those of biopsy. Scans for 38 of the patients were evaluated; one patient's scan could not be evaluated. There were 11 true-positive, two false-positive, 24 true-negative and one false-negative scans for the detection of melanoma metastases, with sensitivity 91%, specificity 92%, accuracy 92%, and positive and negative predictive values 84% and 96%, respectively. False-positive FDG-PET/CT scans were due to sarcoidosis in the lung and infected cyst in the liver. It is concluded that FDG-PET/CT scanning has high sensitivity and specificity for detecting stage III or IV metastatic melanoma.

Standardized uptake values of normal organs on 18F-fluorodeoxyglucose positron emission tomography and computed tomography imaging.

Standardized uptake values (SUVs) of normal organs were evaluated by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and computed tomography (PET-CT) scanning. Seventy patients (38 men and 32 women) with no non-physiological 18F-FDG uptake participated in the study. All patients fasted for at least 4 h before PET-CT imaging and their fasting blood glucose levels were within the normal range. Image acquisition was performed after intravenous administration of 18F-FDG and images were obtained from the vertex to the upper thigh region. The SUVs of various organs were determined from the transverse views. The uptake of 18F-FDG was highest in the cerebrum, cerebellum, myocardium, tonsils, liver and spleen in both sexes. Having knowledge of the physiological uptake of 18F-FDG and normal organ SUVs is required for the correct interpretation of whole-body 18F-FDG-PET-CT studies.

Usefulness of 99mTc-ciprofloxacin (infecton) scan in diagnosis of chronic orthopedic infections: comparative study with 99mTc-HMPAO leukocyte scintigraphy.

UNLABELLED: 99mTc-labeled ciprofloxacin (infecton) has been developed for detecting infectious foci, which localize in high concentrations in living bacteria. Other studies performed with various infections in animals and humans have found that infecton is a promising agent with better specificity for bacterial infections than white blood cell (WBC) scans. In this study, we evaluated the efficacy of infecton scintigraphy for detecting chronic bone and joint infections. METHODS: Fifty-six sites with suspected bone or joint infection were examined with 99mTc-WBC and infecton scans in 51 patients. Of these patients, 21 had prosthetic implant materials. Biochemical, radiologic, and microbiologic data and clinical outcomes also contributed, along with the results from scintigraphic techniques, in determining the presence or absence of infection. Scintigraphic images were produced at 1 and 4 h after injection of 370-400 MBq infecton or 185-200 MBq 99mTc-hexamethylpropyleneamine oxime (HMPAO)-WBCs. For each patient, there were at least 2 d and at most 7 d between scintigraphic studies. RESULTS: There were 30 true-positive, 4 false-positive, 20 true-negative, and 2 false-negative results with infecton. With 99mTc-HMPAO-WBCs, the results were 20, 1, 23, and 12, respectively. Values for sensitivity, specificity, and accuracy were 94%, 83%, and 89%, respectively, with the infecton scan and 63%, 96%, and 77%, respectively, with WBC scanning. Differences between the two agents were statistically significant (P < 0.001). Infecton and WBC scan results were in general concordance for 43 of 56 sites (77%). Infecton results for vertebral infections were the most notable findings in this study, despite the limited number of patients with this condition. Infecton scans were positive for hot spots in five of six patients with vertebral osteomyelitis. WBC scans showed photon-deficient areas in four of these same patients and normal distribution in the remaining two patients. CONCLUSION: Infecton is a useful agent for detecting infectious foci in bones and joints. Moreover, the infecton scan seems to be a more powerful tool in diagnosing vertebral infections than WBC scintigraphy.

The effect of P-glycoprotein function inhibition with cyclosporine A on the biodistribution of Tc-99m sestamibi.

PURPOSE: The failure to cure persons with cancer is caused primarily by the development of drug resistance by overexpression of p-glycoprotein. Diverse groups of drugs have been identified, including cyclosporine A, which can reverse drug resistance by inhibiting P-glycoprotein transport. Tc-99m sestamibi is a substrate for P-glycoprotein. P-glycoprotein is normally expressed in biliary canalicular surfaces of hepatocytes and is responsible for the excretion of cationic metabolites from the liver. The aim of the current study was to evaluate the effect of cyclosporine A on the biological distribution of Tc-99m sestamibi in vivo. METHODS: Five patients with alopecia and two renal transplant patients who were treated with cyclosporine A were selected for the study. All patients were examined before and at least 2 weeks after administration of cyclosporine A. Tc-99m sestamibi scintigraphy was performed by obtaining planar abdominal images at 5, 30, 60, 120, and 180 minutes after injection, and the liver-heart ratios were calculated. RESULTS: Plasma cyclosporine A, bilirubin levels, liver enzymes, and creatinine clearance values were obtained from all patients. In three, the plasma cyclosporine A level was increased to more than 400 pg/dl. The liver-heart ratio was increased significantly after cyclosporine A administration (P < 0.01). After cyclosporine A administration Tc-99m sestamibi excretion was delayed and the uptake in the liver was increased. The difference was 17% at 5 minutes and 38% at 180 minutes. Liver retention was greatest in patients with cyclosporine A toxicity. CONCLUSIONS: With a limited number of patients, this study suggests that Tc-99m sestamibi excretion from the liver is mediated by P-glycoprotein, and inhibition of P-glycoprotein transport not only delays liver excretion but also increases the liver uptake of Tc-99m sestamibi. Because this observation deserves further investigation, the inhibition of P-glycoprotein function with nontoxic multidrug-resistance reversing agents may be used as an intervention to increase the tumor uptake of Tc-99m sestamibi and to increase the sensitivity of Tc-99m sestamibi tumor imaging.