Prognostic value of pretreatment tumor-to-blood standardized uptake ratio (SUR) in rectal cancer.

OBJECTIVES: The prognostic value of SUV on pretreatment F-18 FDG PET/CT imaging in patients with rectal cancer is a matter of debate. SUR is of prognostic value for survival in different cancers. In this study, we aimed to examine the potential prognostic value of SUR and other parameters in pretreatment F-18 FDG PET/CT for non-metastatic rectal cancer. METHODS: One hundred four non-metastatic rectal cancer patients who underwent pretreatment PET/CT between March 2012 and January 2018 were included in the study. Firstly, SUVmax, SUVmean, MTV, and TLG were calculated semi-automatically at the workstation. SUR was calculated as the ratio of tumor SUVmax to thoracic aorta blood SUVmean. Univariate Cox regression and Kaplan-Meier analysis were used to evaluate overall survival (OS), progression free survival (PFS), and local recurrence (LR). Then, multivariate Cox regression analysis, which included the parameters that were significant in the univariate analysis, was performed. RESULTS: Multivariate Cox regression analysis revealed that SUR was a prognostic factor for PFS. Age and T stage were prognostic factors for both OS and PFS. MTV was found to be independent risk factors for OS. CONCLUSIONS: In our study, SUR was the only F-18 FDG PET/CT parameter found to be significant for PFS. The development of new parameters can increase the prognostic value of F-18 FDG PET/CT.

The impact of PET/CT imaging performed in the early postoperative period on the management of breast cancer patients.

OBJECTIVES: The aim of the study was to evaluate the role of F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) in the early postoperative staging of breast cancer and to document (18)F-FDG PET/CT-based stage alterations and any subsequent impact on management. MATERIALS AND METHODS: Between January 2009 and June 2012, PET/CT images of patients with histopathologically proven breast cancer who underwent surgery with no previous chemotherapy or radiotherapy were retrospectively reviewed. Any stage alteration due to a change in nodal or metastatic status on PET/CT was noted. RESULTS: A total of 77 women (median age: 52 years; range: 26-87 years) were included. PET/CT revealed distant metastases that were previously undetected in 12 of the 77 women (15.6%). Of these women, one (8.3%) was diagnosed with stage I, four (33.3%) with stage II, and seven (58.4%) with stage III disease before the PET study. In two patients, lung lesions were diagnosed as metastases by conventional imaging methods, and in one patient the lesions were revealed to have a low probability for malignancy on PET/CT, and they were confirmed as benign on follow-up CT. Thus, changes in disease stage occurred in 15 of 77 (19.5%) patients following PET/CT. The disease was upstaged in 14 patients (18.2%) and downstaged in one (1.3%). CONCLUSION: The impact of (18)F-FDG PET/CT is highest in newly diagnosed stage III breast cancer because of the identification of previously undetected extra-axillary lymph nodes and distant metastases. Early postoperative (18)F-FDG PET/CT imaging may alter the staging and potentially contribute to the management of these patients.

The clinical value of incidental 18F-fluorodeoxyglucose-avid foci detected on positron emission tomography/computed tomography.

OBJECTIVE: This study was performed to show the malignant potential and clinical value of incidental focal 18F-fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography/computed tomography (PET/CT) with the confirmation of histopathologic findings or with a series of consequent correlative imaging methods. METHODS: A total of 2370 18F-FDG-PET/CT studies performed over a 16-month period in patients with various malignant diseases were retrospectively reviewed. Unexpected PET foci that were in an unusual site for metastatic spread of known malignancy and not considered to be physiologic uptake were evaluated by histopathologic findings or follow-up with correlative imaging methods for a period of 1 year or longer. There were 121 such incidental PET lesions in 116 patients. RESULTS: Seventy-four incidental PET lesions in 70 PET/CT patients were investigated further. Forty-seven lesions in 46 patients were lost to follow-up. Fifty-nine lesions were confirmed histopathologically. Fifteen lesions were evaluated with radiologic methods or instrumental examination. Thirty-six incidental PET foci were unexpected malignant or premalignant lesions (1.5% of 2370 patients and 49% of 74 PET foci). Nineteen of these 36 malignant or premalignant lesions were synchronous carcinomas, 14 lesions were unusual or unexpected malignant spread of known malignancy and three lesions were premalignant colonic adenomas. Thirty-three of 74 incidental PET lesions were of benign origin (1.4% of 2370 patients and 44% of 74 PET foci). Five PET foci were false-positive findings (7% of 74 lesions). CONCLUSION: The detection of incidental 18F-FDG-PET foci on PET/CT may reflect unexpected malignant lesions related to unusual malignant spread of primary malignancy or synchronous tumor. Follow-up of these PET foci may result in significant change in therapy management and early diagnosis of various abnormalities that require a medical approach or surgical intervention.

Comparison of SPECT findings and neuropsychological sequelae in carbon monoxide and organophosphate poisoning.

Abnormal regional cerebral blood flow in patients with acute carbon monoxide (CO) and organophosphate (OP) poisoning was examined using (99m)Tc-hexamethylpropylene amine oxime (HMPAO) brain single photon emission computed tomography (SPECT) in fourteen patients. We evaluated the predictive significance of acute phase brain SPECT findings for long-term neuropsychological sequelae. Changes were found in the frontal, temporal, parietal lobes within the first week after both types of poisoning. The distribution of the hypoperfused cerebral areas as demonstrated by (99m)Tc-HMPAO imaging was similar in the two groups during the acute phase. Neuropsychological sequelae developed in five patients poisoned with OP and six with CO. Patients who had SPECT findings heterogeneously or in the temporal or frontal lobes displayed disorientation. Those with fronto-parietal and frontal lobe changes displayed mental confusion. Parkinsonism also was observed in patients with parieto-occipital, parietal and frontal lobe lesions. The distribution of these lesions appears to predict the long term sequelae of these poisonings, though additional studies with larger numbers of patients are needed to confirm the role of SPECT imaging in both OP and CO poisonings.

Contribution of 99mTc-sestamibi infusion SPECT to the characterization of fixed perfusion defects.

In patients with coronary artery disease, the distinction between scar and viable myocardium by means of myocardial perfusion imaging (MPI) sometimes can be difficult because of the equivocal meaning of fixed perfusion defects. In this study we examined whether addition of a 99mTc-sestamibi infusion study to the standard MPI could provide extra information regarding the fixed defects. Thirty-seven patients underwent standard MPI and an extra SPECT study in which 99mTc-sestamibi was given as a prolonged constant infusion. Of 324 myocardial segments available for analysis, 134 had fixed or resting perfusion abnormalities on standard MPI studies, of which 25% (33/134) in 12 patients showed partial improvement in the perfusion pattern whereas in 6% (8/134) the improvement was very significant in infusion studies. In 19 patients who were also examined with dobutamine echocardiography, 13 showed concordance between echocardiography and infusion MPI. This study suggests that infusion MPI may provide complementary information to the conventional scintigraphy with regard to interpretation of standard myocardial perfusion scans with fixed defects.

Hand involvement in Behçet's disease.

AIMS: To study the clinical hand findings in Behçet's disease (BD) and to observe scintigraphic changes of these areas. METHODS: Fifty-seven randomly selected BD patients and the patients in the control group (N=40) were evaluated by two blind rheumatologists. The hands were examined for the presence of pain, tenderness, swelling, effusion, erythema, warmth, range of motion and limitation of motion, deformities and muscle atrophy. Then scintigraphic examination of the hands was performed. Control hand scintigrams were obtained from 40 age- and sex-matched patients and were examined by the same two observers. RESULTS: Thirty-two of the 57 patients (56.1%) showed Behçet's clinical hand findings. Terminal phalangeal pulp atrophy was observed in 17 (29.81%), rheumatoid-like hand findings were observed in 16 (28.1%), dorsal interosseos atrophy was observed in 12 (20.05%) and erythema over the digits was observed in 12 (20.05%). Twenty-four patients (42.1%) had scintigraphic involvement. The disease duration was observed to be an important factor for hand findings (P=0.040) and scintigraphic involvement (P=0.011). CONCLUSION: High prevalence of hand involvement in BD and its relationship with disease duration is demonstrated. Hand involvement tends to be overlooked and careful examination is required in the evaluation of BD. The scintigraphic involvement detected in hands requires special consideration, too.

Diagnosis of orotracheal aspiration using radionuclide salivagram.

There are two main Nuclear Medicine techniques, the gastroesophageal reflux scintigraphy with late lung imaging and the nuclear salivagram, for diagnosis of pulmonary aspiration. Each of the techniques can document the two different, antegrade and retrograde, routes of pulmonary aspiration. In this report, we presented a patient with recurrent respiratory problems and emphasized the importance of concomitant use of the two techniques in the radionuclide diagnosis of aspiration.