Normal uptake of <Superscript>18</Superscript>F-FDG in the testis: an assessment by PET/CT

Objective The aim of this study was to assess the physiological uptake of ¹⁸F-fluoro-2-deoxyglucose (FDG) by an apparently normal testis with combined positron emission tomography–computed tomography (PET/CT) and its correlation with age, blood glucose level, and testicular volume. Methods The testicular uptake of ¹⁸F-FDG, expressed as the standardized uptake value (SUV), was measured on PET/CT images in 203 men. The correlation between SUV and age, blood glucose level, and testicular volume was assessed. Results The SUV in the total of 406 testes was 2.44 ± 0.45 (range 1.23–3.85). The SUV was 2.81 ± 0.43 (2.28–3.85) for 30–39 years (n = 12), 2.63 ± 0.45 (1.77–3.75) for 40–49 years (n = 64), 2.46 ± 0.35 (1.44–3.15) for 50–59 years (n = 82), 2.51 ± 0.41 (1.50–3.46) for 60–69 years (n = 86), 2.43 ± 0.47 (1.42–3.29) for 70–79 years (n = 86), and 2.18 ± 0.45 (1.23–3.03) for 80–89 years (n = 76). When we calculated the mean SUV of bilateral testes in each patient, there were significant statistical differences between those in the age group of 30–39 years and 80–89 years, 40–49 years and 80–89 years, and 50–60 years and 80–89 years, when using an unpaired test with Bonferroni correction. The laterality index (|L − R|/(L + R) × 2) in 203 men was 0.066 ± 0.067 (0–0.522). There was a mild correlation between the mean SUV and age (r = −0.284, P < 0.001) as well as between the mean SUV and mean volume (r = +0.368, P < 0.001). There was no correlation between the mean SUV and glucose blood level (r = −0.065, P = 0.358). Conclusions Some uptake of FDG is observed in the normal testis and declines slightly with age. Physiological FDG uptake in the testis should not be confused with pathological accumulation.     

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

Purpose The nucleoside analogue 3′-deoxy-3′-¹⁸F-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-2-¹⁸F-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.     

Diagnostic value of <Superscript>18</Superscript>F-FDG PET/CT in trauma patients with suspected chronic osteomyelitis

Purpose To retrospectively evaluate the diagnostic value of ¹⁸F-FDG PET/CT in trauma patients with suspected chronic osteomyelitis. Methods Thirty-three partial body ¹⁸F-FDG PET/CT scans were performed in 33 patients with trauma suspected of having chronic osteomyelitis. In 10 and 23 patients, infection was suspected in the axial and appendicular skeleton, respectively. In 18 patients, PET/CT was performed in the presence of metallic implants. Histopathology or bacteriological culture was used as the standard of reference. For statistical analysis, sensitivity, specificity and accuracy were calculated in relation to findings of the reference standard. Results Of 33 PET/CT scans, 17 were true positive, 13 true negative, two false positive and one false negative. Eighteen patients had chronic osteomyelitis and 15 had no osseous infection according to the reference standard. Sensitivity, specificity and accuracy for ¹⁸F-FDG PET/CT was 94%, 87% and 91% for the whole group, 88%, 100% and 90% for the axial skeleton and 100%, 85% and 91% for the appendicular skeleton, respectively. Conclusion ¹⁸F-FDG PET/CT is a highly sensitive and specific method for the evaluation of chronic infection in the axial and appendicular skeleton in patients with trauma. PET/CT allows precise anatomical localisation and characterisation of the infectious focus and demonstrates the extent of chronic osteomyelitis with a high degree of accuracy.     

Detection of gastric cancer using <Superscript>18</Superscript>F-FLT PET: comparison with <Superscript>18</Superscript>F-FDG PET

Purpose  We prospectively investigated the feasibility of 3′-deoxy-3′-¹⁸F-fluorothymidine (FLT) positron emission tomography (PET) for the detection of gastric cancer, in comparison with 2-deoxy-2-¹⁸F-fluoro-d-glucose (FDG) PET, and determined the degree of correlation between the two radiotracers and proliferative activity as indicated by Ki-67 index. Methods  A total of 21 patients with newly diagnosed advanced gastric cancer were examined with FLT PET and FDG PET. Tumour lesions were identified as areas of focally increased uptake, exceeding that of surrounding normal tissue. For semiquantitative analysis, the maximal standardized uptake value (SUV) was calculated. Results  For detection of advanced gastric cancer, the sensitivities of FLT PET and FDG PET were 95.2% and 95.0%, respectively. The mean (±SD) SUV for FLT (7.0 ± 3.3) was significantly lower than that for FDG (9.4 ± 6.3 p < 0.05). The mean FLT SUV and FDG SUV in nonintestinal tumours were higher than in intestinal tumours, although the difference was not statistically significant. The mean (±SD) FLT SUV in poorly differentiated tumours (8.5 ± 3.5) was significantly higher than that in well and moderately differentiated tumours (5.3 ± 2.1; p < 0.04). The mean FDG SUV in poorly differentiated tumours was higher than in well and moderately differentiated tumours, although the difference was not statistically significant. There was no significant correlation between Ki-67 index and either FLT SUV or FDG SUV. Conclusion  FLT PET showed as high a sensitivity as FDG PET for the detection of gastric cancer, although uptake of FLT in gastric cancer was significantly lower than that of FDG.     

The clinical efficacy of <Superscript>18</Superscript>F-FDG-PET/CT in benign and malignant musculoskeletal tumors

Objective  Most of the current clinical data on the role of 2-[¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG-PET) in musculoskeletal tumors come from patients studied with PET and less frequently with hardware fusion PET/computed tomography (CT). And the number of cases in each report is too small to clarify the exact clinical efficacy of PET or PET/CT. This prompted us to analyze our experience with ¹⁸F-FDG-PET/CT in a relatively large group of patients with musculoskeletal tumors. Methods   ¹⁸F-FDG-PET/CT was performed on 91 patients from May 2004 to June 2007. The final diagnosis was obtained from surgical biopsy in 83 patients (91%) and clinical follow-up in 8 (9%). We analyzed the characteristics and amount of ¹⁸F-FDG uptake in soft tissue and bone tumors, and investigated the ability of ¹⁸F-FDG-PET/CT to differentiate malignant from benign tumors. The cutoff maximum standardized uptake value (SUV_max) was calculated using the receiver-operation characteristic curve method. Sensitivity, specificity, and diagnostic accuracy were calculated with cutoff SUV_max and the final diagnosis. Unpaired t test was used for the statistical analysis. Results  Final diagnosis revealed 19 benign soft tissue tumors (mean SUV_max 4.7), 27 benign bone tumors (5.1), 25 malignant soft tissue tumors (8.8), and 20 malignant bone tumors (10.8). There was a significant difference in SUV_max between benign and malignant musculoskeletal tumors in total (P < 0.002), soft tissue tumors (P < 0.05), and bone tumors (P < 0.02). Sensitivity, specificity, and diagnostic accuracy were 80%, 65.2%, and 73% in total with cutoff SUV_max 3.8, 80%, 68.4%, and 75% in the soft tissue tumors with cutoff SUV_max 3.8, and 80%, 63%, and 70% in the bone tumors with cutoff SUV_max 3.7. Conclusions   ¹⁸F-FDG-PET/CT reliably differentiated malignant soft tissue and bone tumors from benign ones, although there were many false-positive and falsenegative lesions. Further studies with all kinds of musculoskeletal tumors in large numbers are needed to improve the diagnostic accuracy of ¹⁸F-FDG-PET/CT.     

<Superscript>18</Superscript>F-FDG PET/CT in sarcoidosis management: review and report of 20 cases

PURPOSE: To evaluate the interest of (18)F-fluoro-2-deoxy-D: -glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for diagnosis and therapeutic follow-up of patients with sarcoidosis. METHODS: Twenty consecutive patients with biopsy-proven sarcoidosis were retrospectively included, in particular, 13 and seven cases of thoracic and extra-thoracic sarcoidosis, respectively. All patients underwent (18)F-FDG PET/CT, and 12 of them also (67)Ga scintigraphy. Five patients were re-examined by (18)F-FDG PET/CT to assess response to corticosteroid (CS) treatment. RESULTS: Sensitivity of (18)F-FDG PET/CT in detecting active sarcoidosis localizations was determined considering only biopsy-proven sites. For thoracic, sinonasal, and pharyngo-laryngeal localizations, (18)F-FDG PET/CT sensitivity was 100%, 100%, and 80%, respectively. Overall sensitivity for all 36 biopsy-proven localizations improved from 78% to 87% after excluding skin involvement. Considering only the 12 patients who underwent both scintigraphic examinations, overall sensitivity of (67)Ga scintigraphy and (18)F-FDG PET/CT was 58% and 79%, respectively and improved to 67% and 86% after excluding all sites of skin involvement. To evaluate the efficacy of CS treatment, five enrolled patients underwent second (18)F-FDG PET/CT. Complete regression of all foci of pathological tracer uptake was showed in two cases, permitting CS withdrawal after 2 and 6 months. Improvement but incomplete regression of mediastino-pulmonary disease occurred in two patients treated with CS for 19 and 21 months. Disease progression was assessed in one patient treated with decreasing doses of CS during 16 months. CONCLUSION: (18)F-FDG PET/CT allows to obtain a complete morpho-functional cartography of inflammatory active localizations and to follow treatment efficacy in patients with sarcoidosis, particularly in atypical, complex, and multisystemic forms.     

Usefulness of <Superscript>18</Superscript>F-FDG PET/CT to Detect Metastatic Mucinous Adenocarcinoma Within an Inguinal Hernia

Metastatic mucinous adenocarcinoma in an inguinal hernia is a rare disease and the image findings of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) are little known. Here, we introduce a 57-year-old man with metastatic mucinous adenocarcinoma in an inguinal hernia. On initial ¹⁸F-FDG PET/CT, hypermetabolism was observed in mucinous adenocarcinoma of the cecum, and adenocarcinomas of the transverse and ascending colon, respectively. Follow-up ¹⁸F-FDG PET/CT revealed newly developed multiple hypermetabolism in peritoneal seeding masses and nodules in the pelvic cavity and scrotum. Peritoneal carcinomatosis in the right pelvic side wall was extended to the incarcerated peritoneum and mesentery in the right inguinoscrotal hernia.¹⁸F-FDG PET/CT was useful to reveal unexpected peritoneal seeding within the inguinal hernia. Also, this case demonstrated that metastatic mucinous adenocarcinomas had variably intense FDG uptake.     

<Superscript>11</Superscript>C-acetate PET imaging of lung cancer: comparison with <Superscript>18</Superscript>F-FDG PET and <Superscript>99m</Superscript>Tc-MIBI SPET

Recently carbon-11 acetate (AC) positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of cancer that is negative on fluorine-18 fluorodeoxyglucoce (FDG) PET. We investigated the uptake of AC in lung cancer to determine whether this tracer is of potential value for tumour detection and characterisation, and to compare AC PET imaging with FDG PET and technetium-99m sestamibi (MIBI) single-photon emission tomography (SPET). Twenty-three patients with 25 lung cancers underwent AC and FDG PET. Twenty of 23 patients were also investigated with MIBI SPET. Dynamic images were acquired for 26 min after the injection of 555 MBq of AC. Standardised uptake values (SUVs) and/or tumour to non-tumour activity ratios (T/N) for each tumour were investigated at 10–20 min after AC administration, 40–60 min after administration of 185 MBq FDG and 15–45 min after administration of 555 MBq MIBI. Twenty lung cancers were resected surgically, and the degree of tracer uptake in the primary lesion was correlated with histopathological features (cell dedifferentiation and aggressiveness) and prognosis. Rapid uptake of AC followed by extremely slow clearance was observed. For the purpose of tumour identification, AC PET was inferior to FDG PET in 8 of 25 (32%) lung cancers, and the T/N of AC was lower than that of FDG. However, AC PET was superior to FDG PET in the identification of a slow-growing tumour (bronchiolo-alveolar carcinoma). There was a positive correlation between AC uptake (T/N) and MIBI uptake (T/N) (r=0.799, P<0.0001). A positive correlation was not observed between either AC or MIBI uptake and the degree of cell dedifferentiation in lung adenocarcinomas, whereas FDG uptake did correlate with the degree of cell dedifferentiation. In lung adenocarcinoma, there was a weak correlation between aggressiveness and FDG uptake, but no correlation was evident for AC and MIBI. In addition, a positive correlation was not observed between AC or MIBI uptake and postoperative recurrence in lung adenocarcinoma, whereas FDG uptake did correlate with postoperative recurrence. Thus, the greater the FDG uptake, the higher the malignant grade. In conclusion, for the purpose of tumour identification, AC PET was inferior to FDG PET but superior to MIBI SPET. Neither AC nor MIBI uptake reflects the malignant grade in lung adenocarcinoma, whereas FDG uptake does. AC PET is less diagnostically informative than FDG PET in patients with lung cancer. However, AC PET may play a complementary role in the identification of low-grade malignancies that are not FDG avid.     

Nonionic intravenous contrast agent does not cause clinically significant artifacts to <Superscript>18</Superscript>F-FDG PET/CT in patients with lung cancer

Objective This study was performed to evaluate the effects of intravenous (i.v.) contrast agent on semi-quantitative values and lymph node (LN) staging of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with lung cancer. Methods Thirty-five patients with lung cancer were prospectively included. Whole-body PET and nonenhanced CT images were acquired 60 min following the i.v. injection of 370 MBq ¹⁸F-FDG and subsequently, enhanced-CT images were acquired with the i.v. administration of 400 mg iodinated contrast agent without positional change. PET images were reconstructed with both nonenhanced and enhanced CTs, and the maximum and average standardized uptake values (SUV_max and SUV_ave) calculated from lung masses, LNs, metastatic lesions, and normal structures were compared. To evaluate the effects of the i.v. contrast agent on LN staging, we compared the LN status on the basis of SUVs (cut-offs; SUV_max = 3.5, SUV_ave = 3.0). Results The mean differences of SUV_max in normal structures between enhanced and nonenhanced PET/CT were 15.23% ± 13.19% for contralateral lung, 8.53% ± 6.11% for aorta, 5.85% ± 4.99% for liver, 5.47% ± 6.81% for muscle, and 2.81% ± 3.05% for bone marrow, and those of SUV_ave were 10.17% ± 9.00%, 10.51% ± 7.89%, 4.95% ± 3.89%, 5.66% ± 9.12%, and 2.49% ± 2.50%, respectively. The mean differences of SUV_max between enhanced and nonenhanced PET/CT were 5.89% ± 3.92% for lung lesions (n = 41), 6.27% ± 3.79% for LNs (n = 76), and 3.55% ± 3.38% for metastatic lesions (n = 35), and those of SUV_ave were 3.22% ± 3.01%, 2.86% ± 1.71%, and 2.33% ± 3.95%, respectively. Although one LN status changed from benign to malignant because of contrast-related artifact, there was no up- or down-staging in any of the patients after contrast enhancement. Conclusions An i.v. contrast agent may be used in PET/CT without producing any clinically significant artifact.     

Optimal dose of <Superscript>18</Superscript>F-FDG required for whole-body PET using an LSO PET camera

Reducing the acquisition time of whole-body fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) (corrected for attenuation) is of major importance in clinical practice. With the introduction of lutetium oxyorthosilicate (LSO), the acquisition time can be dramatically reduced, provided that patients are injected with larger amounts of tracer and/or the system is operated in 3D mode. The aim of this study was to determine the optimal dose of ¹⁸F-FDG required in order to achieve good-to-excellent image quality when a "3-min emission, 2-min transmission/bed position" protocol is used for an LSO PET camera. A total of 218 consecutive whole-body ¹⁸F-FDG PET studies were evaluated retrospectively. After excluding patients with liver metastases, hyperglycaemia and paravenous injections, the final study population consisted of 186 subjects (112 men, 74 women, age 59±15 years). Patients were injected with an activity of ¹⁸F-FDG ranging from 2.23 to 15.21 MBq/kg. Whole-body images corrected for attenuation (3 min emission, 2 min transmission/bed position) were acquired with an LSO PET camera (Ecat Accel,Siemens) 60 min after tracer administration. Patients were positioned with their arms along the body. Image reconstruction was done iteratively and a post-reconstruction filter was applied. Image quality was scored visually by two independent observers using a five-point scoring scale (poor, reasonable, good, very good, excellent). In addition, the coefficient of variability (COV) was measured in a region of interest over the liver in order to quantify noise. Of the images obtained in 118 patients injected with 8 MBq/kg ¹⁸F-FDG, 92% and 90% were classified as good, very good or excellent by observer 1 and observer 2, respectively. The COV averaged 10.63%±3.19% for doses 8 MBq/kg and 16.46%±5.14% for doses <8 MBq/kg. Administration of an ¹⁸F-FDG dose of 8 MBq/kg results in images of good to excellent quality in the vast majority of patients when using an LSO PET camera and applying a 3-min emission, 2-min transmission/bed position acquisition protocol. At lower doses, a rapid decline in image quality and increasing noise are observed. Alternative protocols should be adopted in order to compensate for the loss in image quality when doses <8 MBq/kg are used.     

Correlation between Semi-Quantitative <Superscript>18</Superscript>F-FDG PET/CT Parameters and Ki-67 Expression in Small Cell Lung Cancer

Purpose

The aim of this study was to evaluate the relationship between semiquantitative parameters on ¹⁸F-FDG PET/CT including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) and the expression level of Ki-67 in small-cell lung cancer (SCLC).

Methods

Ninety-four consecutive patients with SCLC were enrolled in this study. They underwent ¹⁸F-FDG PET/CT for initial evaluation of SCLC, and we measured SUVmax, avgSUVmean, MTVsum, and TLGtotal on ¹⁸F-FDG PET/CT images. The protein expression of Ki-67 was examined by immunohistochemical staining.

Results

Significant correlations were found between the MTVsum and Ki-67 labeling index (r = 0.254, p = 0.014) and the TLGtotal and Ki-67 labeling index (r = 0.239, p = 0.020). No correlation was found between the SUVmax and Ki-67 labeling index (r = 0.116, p = 0.264) and the avgSUVmean and Ki-67 labeling index (r = 0.031, p = 0.770). Dividing the Ki-67 expression level into three categories, it was suggested that increasing Ki-67 expression level caused a stepwise increase in the MTVsum and TLGtotal. (p = 0.028 and 0.039, respectively), but not the SUVmax and avgSUVmean (p = 0.526 and 0.729, respectively).

Conclusion

In conclusion, the volume-based parameters of ¹⁸F-FDG PET/CT correlate with immunohistochemical staining of Ki-67 in SCLC. Measurement of the MTVsum and TLGtotal by ¹⁸F-FDG PET/CT might be a simple, noninvasive, and useful method to determine the proliferative potential of cancer cells.     

<Superscript>11</Superscript>C-methionine uptake in cerebrovascular disease: A comparison with<Superscript>18</Superscript>F-FDG PET and<Superscript>99m</Superscript>Tc-HMPAO SPECT

OBJECTIVES: Carbon-11-L-methyl-methionine (11C-methionine) has been reported to be useful for evaluating brain tumors, but several other brain disorders have also shown signs of high methionine uptake. We retrospectively evaluated the significance of 11C-methionine uptake in cerebrovascular diseases, and also compared our results with those for 18F-FDG PET and 99mTc-HMPAO SPECT. METHODS: Seven patients, including 3 patients with a cerebral hematoma and 4 patients with a cerebral infarction, were examined. All 7 patients underwent both 11C-methionine PET and 99mTc-HMPAO SPECT, and 6 of them underwent 18F-FDG PET. RESULTS: A high 11C-methionine uptake was observed in all 3 patients with cerebral hematoma. Increased 99mTc-HMPAO uptake was observed in 2 out of 3 patients, and all 3 patients had decreased 18F-FDG uptake. Of 4 patients with a cerebral infarction, high 11C-methionine uptake was observed in 3. Increased 99mTc-HMPAO uptake was also observed in one patient, whereas 3 patients had decreased 18F-FDG uptake. CONCLUSIONS: We should keep in mind that high 11C-methionine uptake is frequently observed in cerebrovascular diseases. CVD should therefore be included in the differential diagnosis when encounting patients with a high 11C-methionine uptake.     

The role of <Superscript>18</Superscript>F-FDG PET in characterising disease activity in Takayasu arteritis

Takayasu arteritis (TA) is a rare, sporadic and chronic inflammatory arteritis, which predominantly affects the aorta and its branches. Diagnosis can be difficult and there are limitations to the current diagnostic work-up. By detecting areas of active glucose metabolism present in active vasculitis, imaging with fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) could potentially have a role in the management of TA. Our aim was to assess this role by reviewing 28 ¹⁸F-FDG PET scans performed on 18 patients suspected of having TA. All patients had full clinical and laboratory assessment, cross-sectional imaging and angiography, and 16/18 satisfied the American College of Rheumatologists criteria for TA. ¹⁸F-FDG PET achieved a sensitivity of 92%, a specificity of 100%, and negative and positive predictive values of 85% and 100% respectively in the initial assessment of active vasculitis in TA. We conclude that ¹⁸F-FDG PET can be used to diagnose early disease, to detect active disease (even within chronic changes) and to monitor the effectiveness of treatment.     

Standardized uptake values of uterine leiomyoma with <Superscript>18</Superscript>F-FDG PET/CT: variation with age,size, degeneration,and contrast enhancement on MRI

OBJECTIVE: To assess the effect of age, size, the degree of degeneration, and contrast enhancement on magnetic resonance imaging (MRI) on 18F-fluoro-2-deoxyglucose (18F-FDG) uptake in uterine leiomyomas using quantitative standardized uptake values (SUVs). METHODS: A total of 61 leiomyomas of 41 patients, who underwent combined positron emission tomography/computed tomography (PET/CT) using 18F-FDG and contrast-enhanced MRI were included in this study. Sixty-one leiomyomas were divided into two groups: "non-degenerated" leiomyomas showing distinct low signal intensity on T2-weighted images and intermediate signal intensity on T1-weighted images, and "degenerated" leiomyomas showing other types of signal intensity. Sixty-one leiomyomas were also divided into two groups of "strongly enhancing" leiomyomas and "weakly enhancing" leiomyomas in terms of their degree of contrast enhancement on MRI. RESULTS: The mean values of the maximum and average SUVs for the total of 61 leiomyomas were 2.34 +/- 0.75 (range 1.59-5.15) and 1.74 +/- 0.50 (0.66-3.95), respectively. There was a moderate negative correlation between the maximum and average SUVs and age (r = -0.43 and P = 0.00016, r = -0.31 and P = 0.029, respectively). Although there was a mild positive correlation between maximum SUV and size (r = 0.35 and P = 0.011), there was no significant difference between average SUV and size. Although there was no significant difference in average SUV between "degenerated" and "non-degenerated" leiomyomas, the maximum SUV of "degenerated" leiomyomas was significantly higher than that of "non-degenerated" leiomyomas (P = 0.0012). The degree of contrast enhancement on MRI was not significantly correlated with 18F-FDG uptake. CONCLUSIONS: Mild or moderate uptake of 18F-FDG is often observed in uterine leiomyoma and declines with age, and should not be confused with malignant accumulation.     

<Superscript>18</Superscript>F-FDG PET,genotype-corrected ACE and sIL-2R in newly diagnosed sarcoidosis

Purpose  Angiotensin-converting enzyme (ACE) and soluble interleukin-2 receptor (sIL-2R) are serological markers, widely used for determining sarcoidosis activity. ¹⁸F-FDG PET has proven to be a sensitive technique in the imaging of sarcoidosis. The aim of this study was to determine sensitivity of ¹⁸F-FDG PET, genotype-corrected ACE and sIL-2R in active sarcoidosis as well as their correlation. Methods  This retrospective study included 36 newly diagnosed, symptomatic sarcoidosis patients. ACE and sIL-2R levels were simultaneously obtained within 4 weeks of ¹⁸F-FDG PET. ACE was corrected for genotype and expressed as Z-score. ¹⁸F-FDG PET was visually evaluated and scored as positive or negative. Maximum and average standardized uptake values (SUV_max and SUV_avg) were compared with ACE and sIL-2R. Results   ¹⁸F-FDG PET was found positive in 34 of 36 patients (94%). Thirteen patients (36%) showed an increased ACE with the highest sensitivity found in patients with the I/I genotype (67%). Seventeen patients (47%) showed an increased sIL-2R. No correlation was found between SUV and ACE or sIL-2R. Increased ACE and sIL-2R correlated with a positive ¹⁸F-FDG PET in 12 patients (92%) and 16 patients (94%), respectively. Conclusion   ¹⁸F-FDG PET is a very sensitive technique to assess active sarcoidosis, in contrast with ACE and sIL-2R, suggesting a pivotal role for ¹⁸F-FDG PET in future sarcoidosis assessment.     

The impact of <Superscript>18</Superscript>F-FDG PET/CT in patients with liver metastases

Purpose The aim of this study was to assess the performance of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) versus dedicated contrast-enhanced CT (CECT) in the detection of metastatic liver disease. Methods All patients that presented to our Institution with suspected metastatic liver disease who underwent ¹⁸F-FDG PET/CT and CECT within 6 weeks of each other, were retrospectively analyzed, covering a 5-year period. One hundred and thirty-one patients (67 men, 64 women; mean age 62) were identified. Seventy-five had colorectal carcinoma and 56 had other malignancies. The performance of CECT and that of ¹⁸F-FDG-PET/CT in detecting liver metastases were compared. The ability of each to detect local recurrence, extrahepatic metastases and to alter patient management was recorded. The final diagnosis was based on histology, clinical and radiological follow-up (mean 23 months). Results In detecting hepatic metastases, ¹⁸F-FDG-PET/CT yielded 96% sensitivity and 75% specificity, whilst CECT showed 88% sensitivity and 25% specificity. ¹⁸F-FDG-PET/CT and CECT were concordant in 102 out of 131 patients (78%). In the colorectal group ¹⁸F-FDG-PET/CT showed 94% sensitivity and 75% specificity, whilst CECT had 91% sensitivity and 25% specificity. In the noncolorectal group ¹⁸F-FDG-PET/CT showed 98% sensitivity and 75% specificity whilst CECT had 85% sensitivity and 25% specificity. Overall, ¹⁸F-FDG-PET/CT altered patient management over CECT in 25% of patients. CECT did not alter patient management over ¹⁸F-FDG-PET/CT alone in any patients. Conclusion ¹⁸F-FDG-PET/CT performed better in detecting metastatic liver disease than CECT in both colorectal and noncolorectal malignancies, and frequently altered patient management. The future role of CECT in these patients may need to be re-evaluated to avoid potentially unnecessary duplication of investigation where ¹⁸F-PET/CT is readily available. Authors stated no financial relationship to disclose     

Dual-time-point <Superscript>18</Superscript>F-FDG PET imaging for diagnosis of disease type and disease activity in patients with idiopathic interstitial pneumonia

Purpose  Individual clinical courses of idiopathic interstitial pneumonia (IIP) are variable and difficult to predict because the pathology and disease activity are contingent, and chest computed tomography (CT) provides little information about disease activity. In this study, we applied dual-time-point [¹⁸F]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET), commonly used for diagnosis of malignant tumours, to the differential diagnosis and prediction of disease progression in IIP patients. Methods  Fifty patients with IIP, including idiopathic pulmonary fibrosis (IPF, n = 21), non-specific interstitial pneumonia (NSIP, n = 18) and cryptogenic organizing pneumonia (COP, n = 11), underwent ¹⁸F-FDG PET examinations at two time points: scan 1 at 60 min (early imaging) and scan 2 at 180 min (delayed imaging) after ¹⁸F-FDG injection. The standardized uptake values (SUV) at the two points and the retention index (RI-SUV) calculated from them were evaluated and compared with chest CT findings, disease progression and disease types. To evaluate short-term disease progression, all patients were examined by pulmonary function test every 3 months for 1 year after ¹⁸F-FDG PET scanning. Results  The early SUV for COP (2.47 ± 0.74) was significantly higher than that for IPF (0.99 ± 0.29, p = 0.0002) or NSIP (1.22 ± 0.44, p= 0.0025). When an early SUV cut-off value of 1.5 and greater was used to distinguish COP from IPF and NSIP, the sensitivity, specificity and accuracy were 90.9, 94.3 and 93.5%, respectively. The RI-SUV for IPF and NSIP lesions was significantly greater in patients with deteriorated pulmonary function after 1 year of follow-up (progressive group, 13.0 ± 8.9%) than in cases without deterioration during the 1-year observation period (stable group, −16.8 ± 5.9%, p < 0.0001). However, the early SUV for all IIP types provided no additional information of disease progression. When an RI-SUV cut-off value of 0% and greater was used to distinguish progressive IIPs from stable IIPs, the sensitivity, specificity and accuracy were 95.5, 100 and 97.8%, respectively. Conclusion  Early SUV and RI-SUV obtained from dual-time-point ¹⁸F-FDG PET are useful parameters for the differential diagnosis and prediction of disease progression in patients with IIP.     

<Superscript>18</Superscript>F-FDG-PET/CT as an indicator for resection of pulmonary epithelioid hemangioendothelioma

A 60-year-old man with a 7-year history of multiple pulmonary nodules presented to our hospital because the nodules were seen to have increased in size on review of films on a regular medical checkup 1 week earlier. Computed tomography (CT) revealed multiple pulmonary nodules with calcification in the lungs. The largest nodule measuring 2.5 cm in the maximum dimension was lobulated and ill-defined. The patient underwent 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) to evaluate the multiple nodules and to search for a primary lesion. 18F-FDG-PET/CT revealed increased uptake in only two nodules with a standardized uptake value of 4.61 and 2.10, respectively. The two foci with increased 18F-FDG uptake were resected and pathologically proven to be pulmonary epithelioid hemangioendothelioma (PEH). PEH can transform into malignancy with metastasis. An 18F-FDG-PET/CT finding may be an indicator to decide on PEH resection.     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

Purpose Uterine carcinosarcomas clinically confined to the uterus usually harbor occult metastases. We conducted a pilot study to evaluate the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in uterine carcinosarcoma. Methods Patients with histologically confirmed uterine carcinosarcoma were enrolled. Abdominal and pelvic magnetic resonance imaging (MRI)/whole-body computed tomography (CT) scan, and whole-body ¹⁸F-FDG PET or PET/CT were undertaken for primary staging, evaluating response, and restaging/post-therapy surveillance. The clinical impact of ¹⁸F-FDG PET was determined on a scan basis. Results A total of 19 patients were recruited and 31 ¹⁸F-FDG PET scans (including 8 scans performed on a PET/CT scanner) were performed. Positive impacts of scans were found in 36.8% (7/19) for primary staging, 66.7% (2/3) for monitoring response, and 11.1% (1/9) for restaging/post-therapy surveillance. PET excluded falsely inoperable disease defined by MRI in two patients. Aggressive treatment applying to three patients with PET-defined resectable stage IVB disease seemed futile. Two patients died of disease shortly after salvage therapy restaged by PET. With PET monitoring, one stage IVB patient treated by targeted therapy only was alive with good performance. Using PET did not lead to improvement of overall survival of this series compared with the historical control (n = 35) (P = 0.779). Conclusions The preliminary results suggest that ¹⁸F-FDG PET is beneficial in excluding falsely inoperable disease for curative therapy and in making a decision on palliation for better quality of life instead of aggressive treatment under the guidance of PET. PET seems to have limited value in post-therapy surveillance or restaging after failure.     

Impact of dual-time-point <Superscript>18</Superscript>F-FDG PET imaging and partial volume correction in the assessment of solitary pulmonary nodules

Purpose Our aim was to assess the diagnostic potential of ¹⁸F-FDG PET using partial volume correction and dual-time-point imaging in the assessment of solitary pulmonary nodules. Methods We included 265 patients in this retrospective study (171 men; 94 women; age range, 41–92 years). All had pulmonary nodules on CT, and diagnosis was confirmed by biopsy or follow-up CT. All underwent whole body FDG PET, 60 min after FDG injection. Of the 265 patients, 255 underwent second FDG PET for chest 100 min after injection. Maximum SUVs for nodules were calculated from both scans. Partial volume correction for first time SUVs was applied, using coefficient factor. Malignancy was defined using the following criteria: (1) Visual assessment; (2) First time SUV ≥ 2.5; (3) Partial volume corrected first time SUV ≥ 2.5; (4) second time SUV ≥ 2.5; (5) Increase in SUV over time; (6) Increase or no change in SUV; (7) First time SUV ≥ 2.5 and/or increase or no change in SUV. Results Biopsy and follow-up revealed 72 malignant lung nodules and 193 benign nodules. Sensitivity, specificity and accuracy for the five criteria were as follows: (1) 97, 58 and 68%; (2) 65, 92 and 85%; (3) 84, 91 and 89%; (4) 90, 80 and 83%; (5) 84, 95 and 92%; (6) 92, 92, and 92%; (7) 95, 90 and 91%, respectively. Conclusion Dual-time-point ¹⁸F-FDG PET has potential impact on improving the diagnostic accuracy for malignant lung nodules. Dual-time-point ¹⁸F-FDG PET imaging should be included in the clinical work-up of patients with pulmonary nodule.