Impact of incidental irradiation on clinically uninvolved nodal regions in patients with advanced non-small-cell lung cancer treated with involved-field radiation therapy: does incidental irradiation contribute to the low incidence of elective nodal failure?

PURPOSE: To evaluate the incidental irradiation dose to elective nodal regions in the treatment of advanced non-small-cell lung cancer with involved-field radiation therapy (IF-RT) and the pattern of elective nodal failure (ENF). METHODS AND MATERIALS: Fifty patients with advanced non-small-cell lung cancer, who received IF-RT at Kagawa University were enrolled. To evaluate the dose of incidental irradiation, we delineated nodal regions with a Japanese map and the American Thoracic Society map (levels 1-11) in each patient retrospectively and calculated the dose parameters such as mean dose, D95, and V95 (40 Gy as the prescribed dose of elective nodal irradiation). RESULTS: Using the Japanese map, the median mean dose was more than 40 Gy in most of the nodal regions, except at levels 1, 3, and 7. In particular, each dosimetric parameter of level 1 was significantly lower than those at other levels, and each dosimetric parameter of levels 10 to 11 ipsilateral (11I) was significantly higher than those in other nodal regions. Using the American Thoracic Society map, basically, the results were similar to those of the Japanese map. ENF was observed in 4 patients (8%), five nodal regions, and no mean dose to the nodal region exceeded 40 Gy. On the Japanese map, each parameter of these five nodal region was significantly lower than those of the other nodal regions. CONCLUSIONS: These results show that a high dose of incidental irradiation may contribute to the low incidence of ENF in patients who have received IF-RT.

Positron emission tomography with the glucose analog [F]-fluoro-2-deoxy-D-glucose for evaluating pelvic lymph node metastasis in uterine corpus cancer: comparison with CT and MRI findings.

OBJECTIVE: The aims of this study were to investigate the ability of positron emission tomography (PET) with the glucose analog [(18)F]-fluoro-2-deoxy-D-glucose (FDG) to detect pelvic lymph node metastasis of uterine corpus cancer and to perform a retrospective comparison with computed tomography (CT) and magnetic resonance imaging (MRI) findings. METHODS: Forty-six patients with uterine corpus cancer scheduled for surgery, including bilateral pelvic and/or para-aortic lymphadenectomy, were eligible for this study. CT and MRI of the pelvis and abdomen were performed in all patients within 2 weeks preceding whole-body FDG-PET. FDG-PET images were analyzed visually for objective assessment of regional tracer uptake. The sensitivity and specificity of each imaging modality for detecting pelvic lymph node metastasis were determined, respectively. RESULTS: Eleven (7 with myometrial invasion less than 1/2, 4 with myometrial invasion over 1/2) of the 46 patients (23.9%) were revealed to have pelvic lymph node metastasis. The sensitivity and specificity for detecting pelvic lymph node metastasis in patients with uterine corpus cancer by FDG-PET were 31.3% and 96.1% by lymph node region, respectively, and 36.4% and 91.4% by patient, respectively. No significant difference was noted among each imaging modality with sensitivity or specificity. Moreover, the sensitivity and specificity for detecting pelvic lymph node metastasis in 29 patients with endometrioid adenocarcinomas by FDG-PET were 28.6% and 96.1% by lymph node region, respectively, and 50% and 92% by patient, respectively. No significant difference was noted among each imaging modality in terms of sensitivity or specificity. Among 11 patients with pathologically positive pelvic lymph node metastasis, three out of four patients with myometrial invasion over 1/2 were diagnosed as pelvic lymph node metastasis positive by all diagnostic modalities, however, only one of seven patients with myometrial invasion less than 1/2 was diagnosed as pelvic lymph node metastasis positive by PDF-PET and CT. MRI could not detect pelvic lymph node metastasis in patients with myometrial invasion less than 1/2. CONCLUSIONS: We suggest that current imaging modalities including FDG-PET cannot change medical management of patients with uterine corpus cancer before surgery.

Evaluation of the therapeutic effects and recurrence for head and neck cancer after chemoradiotherapy by FDG-PET.

OBJECTIVE: The purpose of this study was to detect early stage recurrence or a residual tumor after chemoradiotherapy by FDG-PET. METHODS: A total of 51 head and neck cancer lesions in 27 patients were examined-including primary sites and metastatic lymph nodes. The therapeutic effects were evaluated by visual inspection, pre-treatment SUV, post-treatment SUV and % change in SUV. RESULTS: No local recurrence was observed in 37 of the lesions, while recurrence or a residual tumor was observed in the other 14 lesions after therapy. A significant difference was found between the two groups regarding the post-treatment SUV and the % change in SUV. Taking the post-treatment SUV of 3 and the % change of 60 as a cut-off value, a significant difference was thus found between the recurrence cases and non-recurrence cases. When all lesions were divided into two groups-including the post-treatment SUV>3 and the % change in the SUV<60 group, and the post-treatment SUV<3 or the % change in SUV>60 group, the overall accuracy was 88.2% (45/51). Therefore, it is more useful to predict the prognosis after chemoradiotherapy by a combined analysis of the post-treatment SUV and the % change in SUV. According to the post-treatment PET period, namely, within 4 weeks and from 5 to 15 weeks after treatment, the accuracy was 85.7% (24/28) and 91.3% (21/23), respectively (p=0.5385). CONCLUSION: The results suggest that it may be possible to predict the recurrence even at 4 weeks after treatment. Therefore, the use of a semi-quantitative analysis of FDG-PET between the pre-treatment and post-treatment findings is thus considered to be helpful in choosing the optimal therapy and for making an accurate prognosis.

Relationship between myocardial flow reserve by oxygen-15 water positron emission tomography in the subacute phase of myocardial infarction and left ventricular remodeling in the chronic phase.

The purposes of this study were to examine the effects of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) on myocardial flow reserve in patients with acute myocardial infarction (AMI) in the subacute phase using oxygen-15 positron emission tomography (PET) and to elucidate the relationship between the myocardial flow reserve and remodeling in the chronic phase. Sixty patients who had been treated with coronary angioplasty within 12 h after the onset of AMI were enrolled. Patients were divided into an enalapril (ACEI) group and a candesartan (ARB) group. The myocardial flow reserve was measured by oxygen-15 water PET in the subacute phase from the 20th to the 30th day after the onset of AMI. Left ventriculography was performed to measure the left ventricular ejection fraction in the chronic phase about 6 months after the onset. Ten patients (33%) in the enalapril group and 4 patients (13%) in the candesartan group stopped taking their respective medications within a few days of starting, because of side effects such as cough or hypotension. Thus, the prevalence of medication intolerance was higher in the enalapril group. The myocardial flow reserve in the subacute phase and the left ventricular ejection fraction in the chronic phase were lower in the enalapril group (2.08 +/- 0.30 and 42 +/- 6%) than in the candesartan group (2.25 +/- 0.20 and 49 +/- 5%) (p < 0.05). The myocardial flow reserve significantly correlated with the left ventricular ejection fraction in all patients (r = 0.45, p < 0.01). The myocardial flow reserve assessed by PET in the subacute phase after AMI was found to be related to left ventricular remodeling in the chronic phase.

Does three-dimensional power Doppler ultrasound improve the diagnostic accuracy for the prediction of adnexal malignancy?

OBJECTIVE: The aim of the present study was to investigate the diagnostic accuracy of three-dimensional power Doppler ultrasound (3DPD) in the differentiation between benign and malignant adnexal masses and evaluate 3DPD for assessing malignancy in comparison with two-dimensional transvaginal gray-scale sonography (2DTVS), magnetic resonance imaging (MRI) and positron emission tomography (PET). SUBJECTS AND METHODS: Thirty-six patients with suspicious adnexal masses were included in this study. 2DTVS and 3DPD were performed preoperatively. MRI and PET examinations were also carried on within two weeks of initial sonography. All the results of diagnostic imaging techniques were evaluated separately. Final diagnosis was confirmed by the postoperative histopathology. The mature cystic teratomas and endometriomas with typical gray-scale sonographic appearance were excluded from the study. RESULTS: Of the 36 patients, 25 had a malignancy, 5 had a borderline tumor, and 6 had a benign mass. Sensitivity of 2DTVS, 3DPD, MRI and PET were 96.7%, 76.7%, 96.7% and 83.3%, respectively. The sensitivity of 2DTVS was as high as that of MRI, and both of them were significantly higher than those of 3DPD and PET, respectively. There were no significant differences both in specificity and accuracy among these 4 techniques. CONCLUSION: 3DPD did not improve the diagnostic accuracy for the prediction of malignancy in adnexal masses. 2DTVS may still remain an important modality for the prediction of adnexal malignancy.

Detection of hepatocellular carcinoma using 11C-choline PET: comparison with 18F-FDG PET.

UNLABELLED: The purpose of this study was to retrospectively investigate the feasibility of 11C-choline PET, compared with 18F-FDG PET, for the detection of hepatocellular carcinoma (HCC). METHODS: A total of 16 HCC lesions in 12 patients were examined with both 11C-choline PET and 18F-FDG PET. Tumor lesions were identified as areas of focally increased uptake, exceeding that of surrounding noncancerous liver tissue. For semiquantitative analysis, the tumor-to-liver (T/L) ratio was calculated by dividing the maximal standardized uptake value (SUV) in HCC lesions by the mean SUV in noncancerous liver tissue. RESULTS: 11C-choline PET showed a slightly higher detection rate than did 18F-FDG PET for detection of HCC (63% vs. 50%, respectively), although this difference was not statistically significant. 11C-choline PET had a better detection rate for moderately differentiated HCC lesions but not for those poorly differentiated (75% vs. 25%, respectively). In contrast, 18F-FDG PET exhibited the opposite behavior, with corresponding detection rates of 42% and 75%, respectively. The mean 11C-choline SUV and T/L ratio in moderately differentiated HCC lesions were higher than those in poorly differentiated HCC lesions. In contrast, the mean 18F-FDG SUV and T/L ratio in poorly differentiated HCC were higher than those in moderately differentiated HCC. These differences, however, were also not statistically significant. CONCLUSION: 11C-choline PET had a better detection rate for moderately differentiated HCC lesions but not for poorly differentiated HCC lesions, whereas 18F-FDG PET produced the opposite result. 11C-choline is a potential tracer to complement 18F-FDG in detection of HCC lesions.

3'-Deoxy-3'-18F-fluorothymidine as a proliferation imaging tracer for diagnosis of lung tumors: comparison with 2-deoxy-2-18f-fluoro-D-glucose.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of 3'-deoxy-3'-F-fluorothymidine (FLT) positron emission tomography (PET) for detection of lung tumor in comparison with 2-deoxy-2-F-fluoro-D-glucose (FDG) PET. METHODS: Fifty-four patients with newly diagnosed pulmonary nodules on chest computed tomographic (CT) scan suggestive of a malignant tumor were examined with both FLT and FDG PET. The intensity of uptake in lung tumors was scored. For visualized lesions, the maximum standardized uptake value (SUV) was calculated. RESULTS: Thirty-six patients were found to have lung cancer; and 18, benign lesions. Using visual analysis, the sensitivity of FLT PET for detection of lung cancer was 83%; the specificity, 83%; and the accuracy, 83%. The corresponding values for FDG PET were 97%, 50%, and 81%, respectively. The specificity of FLT PET was significantly higher than that of FDG PET. The uptake of FLT in lung cancer was significantly lower than that of FDG. Using semiquantitative analysis, the sensitivity of FLT was 86%; the specificity, 72%; and the accuracy, 81%. The corresponding values for FDG were 89%, 67%, and 81%, respectively. CONCLUSIONS: These preliminary results indicate that FLT PET may be specific for malignant tumors although uptake of FLT in lung cancer was significantly lower than that of FDG.

Dual-time-point FDG-PET for evaluation of lymph node metastasis in patients with non-small-cell lung cancer.

OBJECTIVE: The objective of this study was to retrospectively evaluate whether delayed additional F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging can improve the certainty of this modality in evaluating lymph node metastasis in patients with non-small-cell lung cancer (NSCLC). METHODS: Eighty-three patients with NSCLC were examined. FDG-PET imaging (whole body) was performed at 1-h (early) post-FDG injection and repeated 2 h (delayed) after injection only in the thoracic area. The PET images were evaluated qualitatively for regions of focally increased metabolism. If a lymph node was visible on the PET image, the semi-quantitative analysis using the standardized uptake value (SUV) was determined for both early and delayed images (SUV(early) and SUV(delayed), respectively). Retention index (RI) was then calculated on the basis of the following equation: (SUV(delayed) - SUV(early)) x 100/SUV(early). The RI value of more than 0% was taken to be the PET criterion for malignancy. RESULTS: For early and delayed PET, sensitivities for lymph node staging were 54% and 62%, respectively, specificities were 89% for both, and accuracies were 78% and 81%, respectively. The results of combined delayed PET and RI showed a sensitivity of 62%, specificity of 96%, and accuracy of 86%. CONCLUSIONS: Dual-time-point FDG-PET (combined delayed PET and RI) showed better (although not statistically significant) specificity, positive predictive value, and accuracy than early or delayed PET alone for lymph node staging in NSCLC.

Comparison of (18)F-FLT PET and (18)F-FDG PET for preoperative staging in non-small cell lung cancer.

PURPOSE: The nucleoside analog 3'-deoxy-3'-(18)F-fluorothymidine (FLT) has been introduced for imaging cell proliferation with positron emission tomography (PET). We prospectively compared the diagnostic efficacy of FLT PET with that of 2-deoxy-2-(18)F-fluoro-D-glucose (FDG) PET for the preoperative nodal and distant metastatic staging of non-small cell lung cancer (NSCLC). METHODS: A total of 34 patients with NSCLC underwent FLT PET and FDG PET. PET imaging was performed at 60 min after each radiotracer injection. The PET images were evaluated qualitatively for regions of focally increased metabolism. For visualized primary tumors, the maximum standardized uptake value (SUV) was calculated. Nodal stages were determined by using the American Joint Committee on Cancer staging system and surgical and histologic findings reference standards. RESULTS: For the depiction of primary tumor, sensitivity of FLT PET was 67%, compared with 94% for FDG PET (P = 0.005). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for lymph node staging on a per-patient basis were 57, 93, 67, 89, and 85%, respectively, with FLT PET and 57, 78, 36, 91, and 74%, respectively, with FDG PET (P > 0.1 for all comparisons). Two of the three distant metastases were detected with FLT and FDG PET. CONCLUSION: In NSCLC, FLT PET showed better (although not statistically significant) specificity, positive predictive value and accuracy for N staging on a per-patient basis than FDG PET. However, FDG PET was found to have higher sensitivity for depiction of primary tumor than FLT PET.

Monitoring the neoadjuvant therapy response in gynecological cancer patients using FDG PET.

PURPOSE: We retrospectively evaluated the ability of FDG PET to predict the response of primary tumor to chemotherapy or chemoradiotherapy in patients with gynecological cancer. METHODS: FDG PET examinations were performed before and after completion of chemotherapy or chemoradiotherapy in 21 patients with advanced gynecological cancer (uterine cancer, n = 13; ovarian cancer, n = 8). PET imaging was performed at 1 h after injection. Semi-quantitative analysis was performed using the standardized uptake value (SUV) at the primary tumor for both before and after therapy (SUV(before) and SUV(after), respectively). Percent change value was calculated according to the following equation: (SUV(before) - SUV(after) x 100/SUV(before). Based on histopathological analysis of the specimens obtained at surgery, patients were classified as responders or non-responders. RESULTS: Ten patients were found to be responders and 11 to be non-responders. SUV(after) in responders was significantly lower than that in non-responders (p < 0.005). Taking an arbitrary SUV(after) of 3.8 as the cutoff for differentiating between responders and non-responders, FDG PET showed a sensitivity of 90%, a specificity of 63.6%, and an accuracy of 76.2%. The percent change value in the responders was significantly higher than that in the non-responders (p < 0.0005). Taking an arbitrary percent change of 65 as the cutoff for differentiating between responders and non-responders, FDG PET showed a sensitivity of 90%, a specificity of 81.8%, and an accuracy of 85.7%. CONCLUSION: These findings suggest that FDG PET-derived parameters including SUV and especially percent change value may have the potential to predict response to chemotherapy or chemoradiotherapy in patients with advanced gynecological cancer.

Comparison of early and delayed FDG PET for evaluation of biliary stricture.

OBJECTIVE: We assessed whether delayed FDG PET imaging is more useful for the evaluation of biliary stricture in differential diagnosis of malignancy from benign disease. METHODS: Thirty-seven patients who underwent FDG PET for differential diagnosis of the disease causing biliary stricture were included. FDG PET imaging was performed at 70+/-12 min (early) post FDG injection and repeated 188+/-27 min (delayed) after injection only in the abdominal region. Image analysis was performed with visual interpretation and using a semi-quantitative method if lesion was visible on the PET image. The semi-quantitative analysis using the standardized uptake value (SUV) was determined for both early and delayed images (SUVearly and SUVdelayed, respectively). The tumour-to-normal liver (T/L) ratio was also calculated. RESULTS: The final diagnosis was cholangiocarcinoma in 29 and benign disease in eight patients. In cases of cholangiocarcinoma, visual analysis of FDG PET using the delayed images, improve the diagnosis with one more patient correctly identified. For early and delayed FDG PET, sensitivities were 82.8% and 86.2%, respectively; specificities were 87.5% for both; and accuracies were 83.8% and 86.5%, respectively. Both SUV and T/L ratio derived from delayed images were significantly higher than those derived from early images for cholangiocarcinoma (P<0.0002 and P<0.0001, respectively). CONCLUSION: FDG PET could be useful for differential diagnosis of malignancy from benign disease in patients with biliary stricture. Especially, the delayed targeted FDG PET imaging can be recommended in those patients when early imaging is negative or equivalent, because of increased lesion uptake and increased lesion to background contrast ratio.

[18F]fluorodeoxyglucose positron emission tomography imaging in a case of relapsing polychondritis.

Relapsing polychondritis is a rare multisystemic disease that is characterized by recurrent inflammation of the cartilaginous structures of the external ear, nose, joint, larynx, and tracheobronchial tree. Airway involvement is present in up to 50% of patients with the disease and is a major cause of morbidity and mortality. We describe a patient with relapsing polychondritis presenting with tracheal and bronchial abnormalities that were identified by an increased uptake on [18F]fluorodeoxyglucose positron emission tomography.

Correlation of 18F-FLT and 18F-FDG uptake on PET with Ki-67 immunohistochemistry in non-small cell lung cancer.

PURPOSE: The nucleoside analogue 3'-deoxy-3'-(18)F-fluorothymidine (FLT) has recently been introduced for imaging cell proliferation with positron emission tomography (PET). We prospectively evaluated whether FLT uptake reflects proliferative activity as indicated by the Ki-67 index in non-small cell lung cancer (NSCLC), in comparison with 2-deoxy-2-(18)F-fluoro-D-glucose (FDG). METHODS: A total of 18 patients with newly diagnosed NSCLC were examined with both FLT PET and FDG PET. PET imaging was performed at 60 min after each radiotracer injection. Tumour lesions were identified as areas of focally increased uptake, exceeding background uptake in the lungs. For semi-quantitative analysis, the maximum standardised uptake value (SUV) was calculated. Proliferative activity as indicated by the Ki-67 index was estimated in tissue specimens. Immunohistochemical findings were correlated with SUVs. RESULTS: The sensitivity of FLT and FDG PET for the detection of lung cancer was 72% and 89%, respectively. Four of the five false-negative FLT PET findings occurred in bronchiolo-alveolar carcinoma. The mean FLT SUV was significantly lower than the mean FDG SUV. A significant correlation was observed between FLT SUV and Ki-67 index (r = 0.77; p < 0.0002) and for FDG SUV (r = 0.81; p < 0.0001). CONCLUSION: The results of this preliminary study suggest that, compared with FDG, FLT may be less sensitive for primary staging in patients with NSCLC. Although FLT uptake correlated significantly with proliferative activity in NSCLC, the correlation was not better than that for FDG uptake.

Preoperative identification of subthalamic nucleus for deep brain stimulation using three-dimensional phase sensitive inversion recovery technique.

PURPOSE: We assessed the feasibility of utilizing three-dimensional (3D) phase sensitive inversion recovery (IR) images for preoperatively determining deep brain stimulator position. METHODS: We measured geometric distortion with a grid phantom and evaluated images of 3 volunteers to determine optimum imaging parameters for 3D phase sensitive IR. RESULTS: Geometric distortion measured less than 1.0%. Respective inversion and recovery times, which provided high T(1) contrast between the subthalamic nucleus and adjacent tissue, were 200 and 4000 ms. In studies of 3 volunteers and 2 patients, the subthalamic nucleus was clearly depicted in 3D phase sensitive IR images. The measured coordinates of the subthalamic nucleus agreed well with those calculated by conventional estimation from midpoint of the anterior and posterior commissure. CONCLUSION: Three-dimensional phase sensitive inversion recovery was useful in visualizing the subthalamic nucleus for effective deep brain stimulation.

Diagnostic value of kinetic analysis using dynamic FDG PET in immunocompetent patients with primary CNS lymphoma.

PURPOSE: The purpose of this study was to investigate the accumulation of FDG in immunocompetent patients with primary central nervous system (CNS) lymphoma using qualitative and quantitative PET images and to compare baseline with follow-up PET after therapy. METHODS: Twelve immunocompetent patients with CNS lymphoma were examined. Dynamic emission data were acquired for 60 min immediately following injection of FDG. In seven patients, repeated PET studies were performed after treatment. Applying a three-compartment five-parameter model, K (1), k (2), k (3), k (4), vascular fraction (V ( B )) and cerebral metabolic rate of glucose (CMR(Glc)) were obtained. We evaluated the FDG uptake visually using qualitative and parametric images and quantitatively using parametric images. RESULTS: A total of 12 lesions were identified in ten patients with newly diagnosed CNS lymphoma. On visual analysis, ten lesions showed an increase on qualitative images, eight showed an increase on K (1) images, 12 showed an increase on k (3) images and ten showed an increase on CMR(Glc) images. On quantitative analysis, k (2), k (3) and CMR(Glc) values of the lesion were significantly different from those of the normal grey matter (p<0.02-0.0005). A total of three lesions were identified in two patients with recurrent tumour. All three lesions showed an increase on qualitative, k (3) and CMR(Glc) images. The K (1), k (2), k (3) and CMR(Glc) values after treatment were significantly different from those obtained before treatment (p<0.04-0.008). CONCLUSION: Kinetic analysis, especially with respect to k (3), using dynamic FDG PET might be helpful for diagnosis of CNS lymphoma and for monitoring therapeutic assessment.

Usefulness of 99mTc-Technegas and 133Xe dynamic SPECT in ventilatory impairment.

AIM: To assess the usefulness of SPECT images using (99m)Tc-Technegas (Technegas) and (133)Xe dynamic single photon emission computed tomography (SPECT) (Xe gas) and high-resolution computed tomography (HRCT), as compared with pathological assessment in the detection of small-airway disease including pulmonary emphysema. METHODS: Seventeen patients with lung cancer were studied. All patients who had undergone both Technegas and Xe gas and CT prior to surgery were examined. SPECT and HRCT results were compared with the results of pathological findings. Histopathological analysis was performed in an area distant from cancer in lobectomy specimens obtained at surgery. Pathological analysis was performed in relation to bronchitis, bronchiolitis, fibrosis of the alveoli and disruption in walls of the alveoli. RESULTS: Pathological abnormality (mild-to-moderate abnormal change) was seen in all 17 cases. Three patients showed low attenuation areas on CT, and abnormal patterns in SPECT images. In 11 of 14 patients who showed normal findings on CT, SPECT imaging depicted abnormal findings. The remaining three patients had no abnormal findings on CT and both SPECT imaging. CONCLUSION: Technegas and (133)Xe SPECT imaging is useful for evaluating small-airway disease including pulmonary emphysema. Furthermore, SPECT imaging is more useful than morphological HRCT imaging in the evaluation of small-airway disease including pulmonary emphysema.

Comparative evaluation of 18F-FDG PET and 67Ga scintigraphy in patients with sarcoidosis.

UNLABELLED: 67Ga scintigraphy has been used for years in sarcoidosis for diagnosis and the extent of the disease. However, little information is available on the comparison of 18F-FDG PET and 67Ga scintigraphy in the assessment of sarcoidosis. The purpose of this study was to compare the uptake of 18F-FDG and 67Ga in the evaluation of pulmonary and extrapulmonary involvement in patients with sarcoidosis. METHODS: Eighteen patients with sarcoidosis were examined. 18F-FDG PET was performed at 1 h after injection of 185-200 MBq 18F-FDG. 67Ga whole-body planar and thoracic SPECT images were acquired 72 h after injection of 111 MBq 67Ga. We evaluated 18F-FDG and 67Ga uptake visually and semiquantitatively using standardized uptake values (SUVs) and the ratio of lesion to normal lumbar spine (L/N ratio), respectively. The presence of pulmonary and extrapulmonary lesions was evaluated histopathologically or by the radiologic findings. RESULTS: Five patients had only pulmonary lesions, 12 patients had both pulmonary and extrapulmonary lesions, and 1 patient had only an extrapulmonary lesion. Both 67Ga planar and SPECT images detected 17 of 21 (81%) clinically observed pulmonary sites. The mean +/- SD of the L/N ratio was 1.97 +/- 1.09. 67Ga planar images detected 15 of 31 (48%) clinically observed extrapulmonary sites. The mean +/- SD of the L/N ratio was 1.17 +/- 0.33. 18F-FDG PET detected all 21 (100%) clinically observed pulmonary sites. The mean +/- SD of the SUV was 7.40 +/- 2.48. 18F-FDG PET detected 28 of 31 (90%) clinically observed extrapulmonary sites. The mean +/- SD of the SUV was 5.90 +/- 2.75. CONCLUSION: The results of this clinical study suggest that 18F-FDG PET can detect pulmonary lesions to a similar degree as 67Ga scintigraphy. However, 18F-FDG PET appears to be more accurate and contributes to a better evaluation of extrapulmonary involvement in sarcoidosis patients.

Dual-time-point 18F-FDG PET for the evaluation of gallbladder carcinoma.

UNLABELLED: Conventional imaging techniques such as ultrasonography, CT, and MRI are able to detect gallbladder abnormalities but are not always able to differentiate a malignancy from other disease processes such as cholecystitis. The purpose of the present study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for differentiating malignant from benign gallbladder disease. METHODS: The study evaluated 32 patients who were suspected of having gallbladder tumors. (18)F-FDG PET (whole body) was performed at 62 +/- 8 min (early) after (18)F-FDG injection and was repeated 146 +/- 14 min (delayed) after injection only in the abdominal region. We evaluated the (18)F-FDG uptake both visually and semiquantitatively. Semiquantitative analysis using the standardized uptake value (SUV) was performed for both early and delayed images (SUV(early) and SUV(delayed), respectively). The retention index (RI) was calculated according to the equation (SUV(delayed) - SUV(early)) x 100/SUV(early). The tumor-to-liver ratio was also calculated. RESULTS: The final diagnosis was gallbladder carcinoma in 23 patients and benign disease in 9 patients. For visual analysis of gallbladder carcinoma, delayed (18)F-FDG PET images improved the specificity of diagnosis in 2 patients. When an SUV(early) of 4.5, SUV(delayed) of 2.9, and RI of -8 were chosen as arbitrary cutoffs for differentiating between malignant and benign conditions, sensitivity increased from 82.6% to 95.7% and 100% for delayed imaging and combined early and delayed imaging (i.e., RI), respectively. With the same criteria, specificity decreased from 55.6% to 44.4% for delayed imaging and combined early and delayed imaging, respectively. The specificity of (18)F-FDG PET improved to 80% in the group with a normal level of C-reactive protein (CRP) and decreased to 0% in the group with an elevated CRP level. For gallbladder carcinoma, both SUV and tumor-to-liver ratios derived from delayed images were significantly higher than the ratios derived from early images (P < 0.0001). CONCLUSION: Delayed (18)F-FDG PET is more helpful than early (18)F-FDG PET for evaluating malignant lesions because of increased lesion uptake and increased lesion-to-background contrast. However, the diagnostic performance of (18)F-FDG PET depends on CRP levels.

A case of non-hodgkin's lymphoma of the ovary: usefulness of 18F-FDG PET for staging and assessment of the therapeutic response.

Primary ovarian lymphoma as the initial manifestation is rare. A 27-year-old woman presented to our hospital with the symptoms of lower abdominal fullness and pollakisuria. CT scan and MRI revealed bilateral ovarian tumors, which showed heterogeneous masses. 18F-FDG PET revealed strong uptake by the abdominal masses, and the maximum standardized uptake value (SUVmax) was 12.5. Abnormal uptake was not shown by other regions. An exploratory laparotomy was performed. Histological findings revealed diffuse large B-cell lymphoma. The clinical stage was IV according to the Ann Arbor system. International prognostic index (IPI) was 3 (high-intermediate risk). Chemotherapy was administered consisting of three courses of an R-CHOP regimen, and 18F-FDG PET and CT scan revealed no signs of involvement 3 months after initiation of the chemotherapy. 18F-FDG PET was a useful method for staging and assessment of the therapeutic response in primary ovarian lymphoma.

Correlation of FDG-PET findings with histopathology in the assessment of response to induction chemoradiotherapy in non-small cell lung cancer.

PURPOSE: The objective of this study was to evaluate the ability of FDG-PET to predict the response of primary tumour and nodal disease to preoperative induction chemoradiotherapy in patients with non-small cell lung cancer (NSCLC). METHODS: FDG-PET studies were performed before and after completion of chemoradiotherapy prior to surgery in 26 patients with NSCLC. FDG-PET imaging was performed at 1 h (early) and 2 h (delayed) after injection. Semi-quantitative analysis was performed using the standardised uptake value (SUV) at the primary tumour. Percent change was calculated according to the following equation: [see text]. Based on histopathological analysis of the specimens obtained at surgery, patients were classified as pathological responders or pathological non-responders. The clinical nodal stage on the post-chemoradiotherapy PET scan was visually determined and compared with the final pathological stage. RESULTS: Eighteen patients were found to be pathological responders and eight to be pathological non-responders. SUV(after) values from both early and delayed images in pathological responders were significantly lower than those in pathological non-responders. The percent change values from early and delayed images in the pathological responders were significantly higher than those in the pathological non-responders. The post-chemoradiotherapy PET scan accurately predicted nodal stage in 22 of 26 patients. CONCLUSION: FDG-PET may have the potential to predict response to induction chemoradiotherapy in patients with NSCLC.