Comparison of choline-PET/CT,MRI, SPECT,and bone scintigraphy in the diagnosis of bone metastases in patients with prostate cancer: a meta-analysis

Published data on the diagnosis of bone metastases of prostate cancer are conflicting and heterogeneous. We performed a comprehensive meta-analysis to compare the diagnostic performance of choline-PET/CT, MRI, bone SPECT, and bone scintigraphy (BS) in detecting bone metastases in parents with prostate cancer. Pooled sensitivity, specificity, and diagnostic odds ratios (DOR) were calculated both on a per-patient basis and on a per-lesion basis. Summary receiver operating characteristic (SROC) curves were also drawn to obtain the area under curve (AUC) and Q* value. Sixteen articles consisting of 27 studies were included in the analysis. On a per-patient basis, the pooled sensitivities by using choline PET/CT, MRI, and BS were 0.91 [95 % confidence interval (CI): 0.83–0.96], 0.97 (95 % CI: 0.91–0.99), 0.79 (95 % CI: 0.73–0.83), respectively. The pooled specificities for detection of bone metastases using choline PET/CT, MRI, and BS, were 0.99 (95 % CI: 0.93–1.00), 0.95 (95 % CI: 0.90–0.97), and 0.82 (95 % CI: 0.78–0.85), respectively. On a per-lesion basis, the pooled sensitivities of choline PET/CT, bone SPECT, and BS were 0.84 (95 % CI: 0.81–0.87), 0.90 (95 % CI: 0.86–0.93), 0.59 (95 % CI: 0.55–0.63), respectively. The pooled specificities were 0.93 (95 % CI: 0.89–0.96) for choline PET/CT, 0.85 (95 % CI: 0.80–0.90) for bone SPECT, and 0.75 (95 % CI: 0.71–0.79) for BS. This meta-analysis indicated that MRI was better than choline PET/CT and BS on a per-patient basis. On a per-lesion analysis, choline PET/CT with the highest DOR and Q* was better than bone SPECT and BS for detecting bone metastases from prostate cancer.     

Comparison of diagnostic ability between 99mTc-MDP bone scan and 18F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

Objective

The aim of this study was to compare the diagnostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) with that of ^99mTc-methylene diphosphonate (^99mTc-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC).

Methods

Ninety-five patients with SCLC who underwent both ¹⁸F-FDG PET/CT and ^99mTc-MDP bone scan for initial staging work-up were retrospectively enrolled. All ¹⁸F-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information.

Results

Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of ¹⁸F-FDG PET/CT was 100?% on a per-patient basis and 87?% on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37?% on a per-patient basis and 29?% on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected.

Conclusions

In patients with SCLC, ¹⁸F-FDG PET/CT showed higher detection rate of bone metastasis than ^99mTc-MDP bone scan. Thus, ¹⁸F-FDG PET/CT can replace bone scan in staging patients with SCLC.     

Clinical impact of “true whole-body” 18F-FDG PET/CT: lesion frequency and added benefit in distal lower extremities

Objectives

The purpose of this study was to evaluate the lesion frequency and incremental added benefit with “true whole-body” ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) of distal lower extremities. We compared this field of view with the typical whole-body view, from head to upper thighs, in numerous patients with known or suspected malignancy.

Methods

True whole-body ¹⁸F-FDG PET/CT, from the top of the head to the bottom of the feet, was performed on 4574 consecutively registered patients with known or suspected malignancy. Using a variable sampling method, the PET images of head and torso were acquired for 90 s per bed position, and the images of lower extremities were acquired for 30 s per position, thus requiring between 22 and 24 min of emission scanning per patient. A log was maintained to record cases of abnormal findings in distal lower extremities outside the typical whole-body field of view. Suspected malignant lesions in distal lower extremities were verified by correlation with pathological findings and clinical follow-up.

Results

Abnormal findings in distal lower extremities were found in 647 (14.1 %; 95 % CI 13.1–15.2 %) of 4574 examinations. Increased FDG uptake was found in 559 examinations (12.2 %; 95 % CI 11.3–13.2 %). Lesions appeared malignant or equivocal in 67 examinations (1.5 %; 95 % CI 1.1–1.8 %) on the PET images. In 42 (0.9 %; 95 % CI 0.6–1.2 %) of 4574 examinations, these lesions were pathologically or clinically proven to be malignant. Detection of these malignancies resulted in changing clinical management in 21 (50 %) of 42 examinations. Definitive benign lesions were found in 492 examinations (10.7 %; 95 % CI 9.9–11.7 %) on the PET images. Abnormal findings were noted in 90 examinations (2.0 %; 95 % CI 1.6–2.4 %) consisting of 88 benign and 2 malignancies on the CT images alone.

Conclusion

True whole-body ¹⁸F-FDG PET/CT was not of high yield and appears to offer little additional benefit, as to detection of additional metastases and involvement, but it may affect clinical management in patients with known or suspected malignancy.     

A retrospective comparison between 68Ga-DOTA-TOC PET/CT and 18F-DOPA PET/CT in patients with extra-adrenal paraganglioma

Purpose

¹⁸F-Fluoro-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by ⁶⁸Ga-DOTA-Tyr³-octreotide (⁶⁸Ga-DOTA-TOC) PET. Therefore, we compared ⁶⁸Ga-DOTA-TOC and ¹⁸F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard.

Methods

A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with ⁶⁸Ga-DOTA-TOC PET and ¹⁸F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUV_max) of each functional imaging modality in concordant tumour lesions was measured.

Results

Compared with anatomical imaging, ⁶⁸Ga-DOTA-TOC PET and ¹⁸F-DOPA PET each had a per-patient and per-lesion detection rate of 100 % in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of ⁶⁸Ga-DOTA-TOC was 100 % and that of ¹⁸F-DOPA PET was 56.0 %. Overall, ⁶⁸Ga-DOTA-TOC PET identified 45 lesions; anatomical imaging identified 43 lesions, and ¹⁸F-DOPA PET identified 32 lesions. The overall per-lesion detection rate of ⁶⁸Ga-DOTA-TOC PET was 100 % (McNemar, P?<?0.5), and that of ¹⁸F-DOPA PET was 71.1 % (McNemar, P?<?0.001). The SUV_max (mean ± SD) of all 32 concordant lesions was 67.9?±?61.5 for ⁶⁸Ga-DOTA-TOC PET and 11.8?±?7.9 for ¹⁸F-DOPA PET (Mann-Whitney U test, P?<?0.0001).

Conclusion

⁶⁸Ga-DOTA-TOC PET may be superior to ¹⁸F-DOPA PET and diagnostic CT in providing valuable information for pretherapeutic staging of extra-adrenal PGL, particularly in surgically inoperable tumours and metastatic or multifocal disease.     

Diagnostic and prognostic value of 18F-FDG PET/CT in recurrent germinal tumor carcinoma

Aim

The aim of this bicentric retrospective study was to assess the diagnostic performance, the prognostic value, the incremental prognostic value and the impact on therapeutic management of ¹⁸F-FDG PET/CT in patients with suspected recurrent germinal cell testicular carcinoma (GCT).

Materials and methods

From the databases of two centers including 31,500 ¹⁸F-FDG PET/CT oncological studies, 114 patients affected by GCT were evaluated in a retrospective study. All 114 patients underwent ¹⁸F-FDG PET/CT for suspected recurrent disease. Diagnostic performance of visually interpreted ¹⁸F-FDG PET/CT and potential impact on the treatment decision were assessed using histology (17 patients), other diagnostic imaging modalities (i.e., contrast enhanced CT in 89 patients and MRI in 15) and clinical follow-up (114 patients) as reference. Progression-free survival (PFS) and overall survival (OS) rates were computed by means of Kaplan-Meier survival analysis. The progression rate (Hazard Ratio-HR) was determined using univariate Cox regression analysis by considering various clinical variables.

Results

Recurrent GCT was confirmed in 47 of 52 patients with pathological ¹⁸F-FDG PET/CT findings, by means of histology in 18 patients and by other diagnostic imaging modalities/follow-up in 29. Sensitivity, specificity, accuracy, positive and negative likelihood ratio (LR+ and LR-, respectively), pre-test Odds-ratio and post-test Odds-ratio of ¹⁸FDG PET/CT were 86.8%, 90.2%, 88.4%, 8.85, 0.14, 0.85, 8.85, respectively.¹⁸F-FDG PET/CT impacted significantly on therapeutic management in 26/114 (23%) cases (from palliative to curative in 12 patients, from “wait and watch” to new chemotherapy in six patients and the “wait-and-watch” approach in eight patients with unremarkable findings). At 2 and 5-year follow-up, PFS was significantly longer in patients with a negative than a pathological ¹⁸F-FDG PET/CT scan (98% and 95% vs 48% and 38%, respectively; p = 0.02). An unremarkable scan was associated also with a longer OS (98% after 2 years and 95% after 5 years, p = 0.02). At univariate Cox regression analysis, a pathological ¹⁸F-FDG PET/CT scan was associated with an increased risk of disease progression (HR = 24.3, CI 95% 14.1-40.6; p = 0.03) and lower OS (HR = 17.3 CI 95% 4,9-77; p < 0.001). Its prognostic value was confirmed also if tested against advanced disease at diagnosis and rising Human Chorionic Gonadotropin Beta (HCGB) or Alpha-Fetoprotein (AFP) (HR = 7.3 for STAGE III-PET+, p = 0.03; HR = 14.3 elevated HCGB-PET+, p = 0.02; HR 10.7 elevated AFP-PET+, p = 0.01) At multivariate analysis, only a pathological ¹⁸F-FDG PET/CT scan and advanced disease in terms of TNM staging were predictors of disease progression and OS. ¹⁸F-FDG PET/CT showed incremental value over other variables both in predicting PFS (chi-square from 24 to 40, p < 0.001) and OS (chi-square from 32 to 38, p = 0.003).

Conclusion

¹⁸F-FDG PET/CT has a very good diagnostic performance in patients with suspected recurrent GCT and has an important prognostic value in assessing the rate of PFS and OS. Furthermore, ¹⁸F-FDG PET/CT impacted the therapeutic regimen in 23% of patients, thus providing a significant impact in the restaging process.

     

Prospective evaluation of magnetic resonance enterography for the detection of mesenteric small bowel tumours

Purpose

To prospectively evaluate magnetic resonance (MR) enterography for detecting mesenteric small-bowel tumours (MSBTs) and assess the added value of gadolinium-chelate injection.

Material and methods

Over a 2-year period MR enterography examinations of 75 patients (33 men, 42 women; mean age, 53.8 years; range, 19–85) with suspected MSBT were blindly analysed by two readers for the presence of MSBT. Sensitivities, specificities, predictive positive values (PPVs), negative predictive values (NPVs) and accuracies of MR enterography for the detection of MSBT were calculated on per-patient and per-lesion bases. The McNemar test was used to compare sensitivities and specificities of the unenhanced and gadolinium-enhanced sets of MR enterographies.

Results

Thirty-seven MSBTs were pathologically confirmed in 26 patients. The mean tolerance score of the examinations was 0.7. On a per-patient basis, sensitivity, specificity, PPV, NPV and accuracy for detection of MSBT were 96 % [95 % CI, 89–100 %], 96 % [90–100 %], 93 % [83–100 %], 98 % [94–100 %] and 96 % [92–100 %], respectively. On a per-lesion basis, sensitivity and PPV were 70 % [56–85 %] and 93 % [83–100 %], respectively. Gadolinium injection yielded higher sensitivities on both bases (P?=?0.008).

Conclusion

MR enterography is an accurate and well-tolerated imaging modality for detecting MSBT. Intravenous administration of gadolinium-chelate improves sensitivity for MSBT detection.

Key Points

? MR enterography accurately detects mesenteric small bowel tumours. ? MR enterography is a well-tolerated imaging technique. ? Intravenous administration of gadolinium chelate improves sensitivity for detecting small-bowel tumours.     

A meta-analysis of 18F-Fluoride positron emission tomography for assessment of metastatic bone tumor

Purpose

The aim of this study was to assess the diagnostic performance of ¹⁸F-Fluoride positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) compared with bone scintigraphy (BS) planar or BS planar and single photon emission computed tomography (SPECT) in evaluating patients with metastatic bone tumor.

Materials and methods

We performed a meta-analysis of all available studies addressing the diagnostic accuracy of ¹⁸F-Fluoride PET, ¹⁸F-Fluoride PET/CT, BS planar, and BS planar and SPECT for detecting the metastatic bone tumor. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and drew summary receiver operating characteristic curves using hierarchical regression models. We also compared the effective dose and cost-effectiveness estimated by data from the enrolled studies between ¹⁸F-Fluoride PET or PET/CT and BS planar or BS planar and SPECT.

Results

When comparing all studies with data on ¹⁸F-Fluoride PET or PET/CT, sensitivity and specificity were 96.2% [95% confidence interval (CI) 93.5–98.9%] and 98.5% (95% CI 97.0–100%), respectively, on a patient basis and 96.9% (95% CI 95.9–98.0%) and 98.0% (95% CI 97.1–98.9%), respectively, on a lesion basis. The Az values of ¹⁸F-Fluoride PET or PET/CT were 0.986 for the patient basis and 0.905 for the lesion basis, whereas those of BS or BS and SPECT were 0.866 for the patient basis and 0.854 for the lesion basis. However, the estimated effective dose and average cost-effective ratio were poorer for ¹⁸F-Fluoride PET or PET/CT than those of BS planar or BS planar and SPECT.

Conclusion

¹⁸F-Fluoride PET or PET/CT has excellent diagnostic performance for the detection of metastatic bone tumor, but the estimated effective dose and average cost-effective ratio are at a disadvantage compared with BS planar or BS planar and SPECT.     

Comparison of FDG PET/CT and MRI in lymph node staging of endometrial cancer

Objective

Endometrial cancer is the most frequent cancer occurring in the female genital tract in the Western countries. Because surgical staging is currently the standard, noninvasive techniques that accurately identify lymph node (LN) metastases would be beneficial by reducing costs and complications. The purpose of our study is to compare the diagnostic accuracy of 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) with that of magnetic resonance imaging (MRI) for detecting LN metastases in the preoperative staging of endometrial cancer.

Methods

Two hundred eighty-seven consecutive patients with endometrial cancer underwent preoperative PET/CT and MRI for staging. The malignancy criteria for LNs were a short diameter of 1 cm or more by MRI and focally increased ¹⁸F-FDG uptake by PET/CT. After evaluating PET/CT and MRI separately, morphologic and functional image findings were compared with the histological findings regarding LN metastasis for all patients. PET/CT and MRI images were classified on the basis of histological findings as true-positive, true-negative, false-positive, or false-negative. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

Results

Histologic examination revealed LN metastases in 51 patients (17.8 %). The maximal standardized uptake values (SUVmax) of the primary lesions by PET/CT ranged from 1.4 to 37.7, with a mean value of 9.3, whereas those of the metastatic LNs ranged from 2.0 to 22.5 with a mean of 7.3. On a per-patient basis, node staging resulted in sensitivities of 70.0 % with ¹⁸F-FDG PET/CT and 34.0 % with MRI, and specificities of 95.4 % with PET/CT and 95.0 % with MRI. The NPV of PET/CT was 94.3 %, and that of MRI was 87.2 %. On a lesion base analysis, sensitivity of PET/CT was 79.4 % while that of MRI was 51.6 %. In detecting distant metastasis, the sensitivity, specificity, accuracy, PPV, and NPV of PET/CT were 92.9, 98.9, 98.6, 81.3, and 99.6 %, respectively.

Conclusion

Diagnostic performance of FDG PET/CT was better than MRI for detecting metastatic lymph nodes in patients with endometrial cancer both by patient basis and lesion basis analyses. Due to high NPV, FDG PET-CT could aid in selecting candidates for lymphadenectomy.

     

Thyroglobulin levels and thyroglobulin doubling time independently predict a positive 18F-FDG PET/CT scan in patients with biochemical recurrence of differentiated thyroid carcinoma

Purpose

To assess the relationship between serum thyroglobulin (Tg) levels, Tg doubling time (Tg-DT) and the diagnostic performance of ¹⁸F-FDG PET/CT in detecting recurrences of ¹³¹I-negative differentiated thyroid carcinoma (DTC).

Methods

Included in the present study were 102 patients with DTC. All patients were treated by thyroid ablation (e.g. thyroidectomy and ¹³¹I), and underwent ¹⁸F-FDG PET/CT due to detectable Tg levels and negative conventional imaging. Consecutive serum Tg measurements performed before the ¹⁸F-FDG PET/CT examination were used for Tg-DT calculation. The ¹⁸F-FDG PET/CT results were assessed as true or false after histological and/or clinical follow-up.

Results

Serum Tg levels were higher in patients with a positive ¹⁸F-FDG PET/CT scan (median 6.7 ng/mL, range 0.7–73.6 ng/mL) than in patients with a negative scan (median 1.8 ng/mL, range 0.5–4.9 ng/mL; P?<?0.001). In 43 (88 %) of 49 patients with a true-positive ¹⁸F-FDG PET/CT scan, the Tg levels were >5.5 ng/mL, and in 31 (74 %) of 42 patients with a true-negative ¹⁸F-FDG PET/CT scan, the Tg levels were ≤5.5 ng/mL. A Tg-DT of <1 year was found in 46 of 49 patients (94 %) with a true-positive ¹⁸F-FDG PET/CT scan, and 40 of 42 patients (95 %) with a true-negative scan had a stable or increased Tg-DT. Moreover, combining Tg levels and Tg-DT as selection criteria correctly distinguished between patients with a positive and a negative scan (P<0.0001).

Conclusion

The accuracy of ¹⁸F-FDG PET/CT significantly improves when the serum Tg level is above 5.5 ng/mL during levothyroxine treatment or when the Tg-DT is less than 1 year, independent of the absolute value.     

Diagnostic accuracy of 18F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma

Purpose

To evaluate the diagnostic accuracy of ¹⁸F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma.

Methods

We retrospectively analysed data from 53 patients (age 20.1?±?10.5 years, 39 male) who had undergone 71 ¹⁸F-FDG PET/CT studies for suspected recurrence (52 studies) or for routine follow-up (19 studies) after primary therapy of skeletal Ewing sarcoma. ¹⁸F-FDG PET/CT studies were evaluated qualitatively and quantitatively (maximum standardized uptake value, SUVmax) by two nuclear medicine physicians in consensus. Sensitivity, specificity, predictive values and accuracy were calculated on per study basis. Clinical/imaging follow-up (minimum 6 months) and/or histopathology (when available) were taken as the reference standard.

Results

Of the total of 71 ¹⁸F-FDG PET/CT studies, 42 (59.1 %) were positive for recurrence and 29 (40.9 %) were negative for recurrence. Local recurrence was most common (38 studies) followed by bone metastasis (9 studies), and node and lung metastasis (2 studies each). Of the 71 studies, 38 were true-positive, 27 were true-negative, 4 were false-positive and 2 were false-negative. Overall per study based sensitivity was 95 %, specificity was 87 %, PPV was 90 %, NPV was 93 % and accuracy was 91.5 %. No significant difference was found in the accuracy of PET/CT between the suspected recurrence group and the routine follow-up group (94 % vs. 84 %; P?=?0.390). Overall mean lesion SUVmax was 7.8?±?4.1 (range 1.9–17.2). No site-based difference was found in SUVmax.

Conclusion

¹⁸F-FDG PET/CT demonstrates high diagnostic accuracy for detecting recurrence in patients with primary skeletal Ewing sarcoma, when it is suspected (clinically or on imaging) or during routine follow-up.     

Hybrid CT angiography and quantitative 15O-water PET for assessment of coronary artery disease: comparison with quantitative coronary angiography

Purpose

CT angiography (CTA) can rule out significant stenoses with a very high reliability, whereas its ability to confirm significant stenoses is suboptimal. In contrast, measurements of myocardial blood flow (MBF) provide information on the haemodynamic consequences of stenoses. Therefore, a combination of the two might improve diagnostic accuracy. We conducted a head-to-head comparison of CTA, measurement of MBF by ¹⁵O-water PET, and hybrid PET/CTA for the detection of significant coronary artery stenoses.

Methods

The study group comprised 44 outpatients scheduled for invasive coronary angiography (ICA) with an intermediate pretest likelihood of coronary artery disease. The patients underwent 64-slice CTA and baseline and hyperaemic PET before ICA with quantitative coronary angiography analysis.

Results

On a per-patient basis, the negative predictive values (NPV; 95 % confidence intervals in parentheses) were 88 % (64 – 97 %) for CTA, 90 % (71 – 97%) for PET and 92 % (74 – 98%) for PET/CTA, and the positive predictive values (PPV) were 71 % (53 – 85%) for CTA, 87 % (68 – 95%) for PET and 100 % (84 – 100%) for PET/CTA. Similarly, on a per-vessel basis the NPVs (which were generally high) were 97 % (94 – 100%) for CTA, 95 % (90 – 99%) for PET and 97 % (95 – 100%) for PET/CTA, and the PPVs (which were lower, but higher with PET/CTA) were 53 % (39 – 66%) for CTA, 53 % (40 – 66%) for PET and 85 % (73 – 97%) for PET/CTA. In six patients, CTA analysis was hampered by the presence of severe calcifications. However, with the addition of the PET data, all six patients were correctly categorized.

Conclusion

Cardiac quantitative hybrid PET/CTA imaging has better diagnostic accuracy than CTA alone and PET alone. CTA has a suboptimal PPV, suggesting that hybrid PET/CTA imaging should be used to assess the significance of coronary stenoses diagnosed by CTA.     

Diagnostic accuracy of 18F-FDG PET/CT for assessing response to radiofrequency ablation treatment in lung metastases: a multicentre prospective study

Purpose

To assess diagnostic accuracy of ¹⁸F-FDG PET/CT at 3 months for the detection of local recurrence after radiofrequency ablation (RFA) of lung metastases.

Methods

The PET/CT scan at 3 months was compared with a baseline PET/CT scan from a maximum of 2 months before RFA, with the reference standard as recurrence diagnosed by CT during a 12-month follow-up. Local recurrence was diagnosed on the PET/CT scan if lesional uptake was greater than the mediastinal background. Maximum standardized uptake values (SUVmax) were recorded. ROC curve analysis for SUVmax was performed. Overall survival (OS) and time to local relapse were computed from the date of RFA using the Kaplan-Meier method (www.clinicaltrials.gov: NCT 00382252).

Results

Between 2005 and 2009, 89 patients (mean age 65 years) underwent RFA for 115 lung metastases (mean size 16.2 ± 6.9 mm). The median SUVmax before RFA was 5.8?±?4. PET/CT at 3 months and the reference standard were available in 77 patients and 100 lesions. Accuracy was 66.00 % (95 % CI 55.85–75.18 %), sensitivity 90.91 % (95 % CI 58.72–99.77 %), specificity 62.92 % (95 % CI 52.03–72.93 %), PPV 23.26 % (95 % CI 11.76–38.63 %), and NPV 98.25 % (95 % CI 90.61–99.96 %). One-year OS was 94.2 % (95 % CI 86.6–97.5 %) and the probability of being free of local recurrence 1 year after RFA was 84.6 % (95 % CI 75.0–90.8 %).

Conclusion

The specificity of PET/CT at 3 months is low because of persistent inflammation, especially when the lesion is close to the pleura. This technique is useful for its negative predictive value, but positive findings need to be confirmed by histology before new treatment is planned.     

Diagnostic Performance of 68Ga-DOTATATE PET/CT, 18F-FDG PET/CT and 131I-MIBG Scintigraphy in Mapping Metastatic Pheochromocytoma and Paraganglioma

Purpose

To evaluate the diagnostic performance of ⁶⁸Ga-DOTATATE ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT), ¹⁸F-FDG PET/CT and ¹³¹I-MIBG scintigraphy in the mapping of metastatic pheochromocytoma and paraganglioma.

Materials and Methods

Seventeen patients (male = 8, female = 9; age range, 13–68 years) with clinically proven or suspicious metastatic pheochromocytoma or paraganglioma were included in this prospective study. Twelve patients underwent all three modalities, whereas five patients underwent ⁶⁸Ga-DOTATATE and ¹³¹I-MIBG without ¹⁸F-FDG. A composite reference standard derived from anatomical and functional imaging findings, along with histopathological information, was used to validate the findings. Results were analysed on a per-patient and on per-lesion basis. Sensitivity and accuracy were assessed using McNemar’s test.

Results

On a per-patient basis, 14/17 patients were detected in ⁶⁸Ga-DOTATATE, 7/17 patients in ¹³¹I-MIBG, and 10/12 patients in ¹⁸F-FDG. The sensitivity and accuracy of ⁶⁸Ga-DOTATATE, ¹³¹I-MIBG and ¹⁸F-FDG were (93.3 %, 94.1 %), (46.7 %, 52.9 %) and (90.9 %, 91.7 %) respectively. On a per-lesion basis, an overall of 472 positive lesions were detected; of which 432/472 were identified by ⁶⁸Ga-DOTATATE, 74/472 by ¹³¹I-MIBG, and 154/300 (patient, n = 12) by ¹⁸F-FDG. The sensitivity and accuracy of ⁶⁸Ga-DOTATATE, ¹³¹I-MIBG and ¹⁸F-FDG were (91.5 %, 92.6 % p < 0.0001), (15.7 %, 26.0 % p < 0.0001) and (51.3 %, 57.8 % p < 0.0001) respectively. Discordant lesions were demonstrated on ⁶⁸Ga-DOTATATE, ¹³¹I-MIBG and ¹⁸F-FDG.

Conclusions

Ga-DOTATATE PET/CT shows high diagnostic accuracy than ¹³¹I-MIBG scintigraphy and ¹⁸F-FDG PET/ CT in mapping metastatic pheochromocytoma and paraganglioma.     

18F-FDOPA与18F-FDG PET/CT诊断脑肿瘤的系统评价

目的 系统评价18F-FDOPA与18F-FDG PET/CT显像在脑肿瘤诊断中的临床价值.方法 采用Meta分析与直接比较方法.使用计算机检索中国期刊全文数据库、中文科技期刊数据库、万方数据库、中国生物医学文献数据库、PubMed、Embase、The Cochrane Library,从建库至2016年10月,搜索直接比较18F-FDOPA与18F-FDG PET/CT诊断脑肿瘤的诊断性试验.用Meta-Disc 1.4软件进行分析,计算两种不同显像剂的合并敏感度(sensitivity,SEN)、合并特异度(specificity,SPE)、合并阳性似然比(positive likelihood ratio,+LR)、合并阴性似然比(negative likelihood ratio,-LR)、诊断优势比(diagnostic odds ratio,DOR),并绘制综合受试者工作特征曲线计算曲线下面积(area under curve,AUC)与Q*值.结果 最终共纳入4篇文章,Meta 分析结果显示,18F-FDOPA PET/CT对脑肿瘤诊断的合并SEN为0.97(95％ CI =0.90 ～ 1.00),SPE为0.67(95％ CI =0.45 ～0.84),+LR为2.31 (95％ CI=1.40 ～3.81),-LR为0.07 (95％ CI =0.02～ 0.24),DOR为39.72(95％ CI=8.94～176.48),AUC为0.9725,Q*为0.9239.18F-FDG PET/CT对脑肿瘤诊断的合并SEN为0.51(95％CI=0.39～0.63),SPE为0.75(95％ CI=0.53 ～0.90,+LR为l.59(95％ CI=0.70 ～ 3.61),-LR为0.63(95％ CI =0.47 ～0.86),DOR为2.55(95％ CI =0.82 ～7.92),AUC为0.5848,Q*为0.5638.结论 18F-FDOPA PET/CT显像诊断脑肿瘤的敏感性比18F-FDG高,对脑肿瘤具有良好的诊断价值,可作为脑肿瘤诊断的方法之一.     

Clinical significance of 18F-α-methyl tyrosine PET/CT for the detection of bone marrow invasion in patients with oral squamous cell carcinoma: comparison with 18F-FDG PET/CT and MRI

Objective

L-3-[¹⁸F]-fluoro-α-methyl tyrosine (¹⁸F-FAMT) is an amino acid tracer for positron emission tomography/computed tomography (PET/CT) which specifically transported into cancer cells by L-type amino acid transporter 1 (LAT1). LAT1 overexpression in tumors is significantly correlated with cell proliferation and angiogenesis. ¹⁸F-FAMT PET/CT, fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT and magnetic resonance imaging (MRI) were compared for their diagnostic performance in the detection of bone marrow invasion in patients with oral squamous cell carcinoma (OSCC).

Methods

Twenty-seven patients with OSCC on the upper or lower alveolar ridge underwent staging by MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT studies before surgery. Post-surgical pathologic examination was used as the standard to determine the final diagnoses. The possibility of bone marrow invasion on MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT were usually graded retrospectively into five-point score. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated according to the obtained scores.

Results

As the sensitivity of ¹⁸F-FDG PET/CT was highest (100 %) among that of MRI (95 %) and ¹⁸F-FAMT PET/CT (90 %), the specificity of ¹⁸F-FAMT PET/CT was highest (85.7 %) among that of MRI (57 %) and ¹⁸F-FDG PET/CT (14.3 %). The size of pathological tumor was accorded with that detected by ¹⁸F-FAMT PET/CT and was smaller than that detected by ¹⁸F-FDG PET/CT (P < 0.01). Significant difference was not found between ¹⁸F-FAMT PET tumor volume and pathological tumor volume.

Conclusions

¹⁸F-FAMT PET/CT was useful and more specific than MRI or ¹⁸F-FDG PET/CT in the detection of bone marrow invasion of OSCC and may contribute to minimize the extent of resection in oral surgery patient.     

The impact of 18F-FDG PET on the management of patients with suspected large vessel vasculitis

Purpose

We aimed to assess the impact of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the management of patients with suspected large vessel vasculitis.

Methods

An international expert panel determined diagnoses and clinical management in patients with suspected large vessel vasculitis, with and without the results of ¹⁸F-FDG PET, respectively. The accuracy of the clinical diagnosis and the resulting clinical management with and without the ¹⁸F-FDG PET results were compared using logistic regression models.

Results

The analysis included 30 patients referred to a tertiary care centre with large vessel vasculitis and 31 controls. ¹⁸F-FDG PET had an overall sensitivity of 73.3% [95% confidence interval (CI) 54.1?C87.7%], a specificity of 83.9% (95% CI 66.3?C94.5%), a positive predictive value of 81.5% (95% CI 61.9?C93.7%) and a negative predictive value of 76.5% (95% CI 58.8?C89.3%). The diagnostic accuracy of ¹⁸F-FDG PET was higher in patients not receiving immunosuppressive drugs (93.3 vs 64.5%, p?=?0.006). Taken in context with other available diagnostic modalities, the addition of ¹⁸F-FDG PET increased the clinical diagnostic accuracy from 54.1 to 70.5% (p?=?0.04). The addition of ¹⁸F-FDG PET increased the number of indicated biopsies from 22 of 61 patients (36.1%) to 25 of 61 patients (41.0%) and changed the treatment recommendation in 8 of 30 patients (26.7%) not receiving immunosuppressive medication and in 7 of 31 patients (22.6%) receiving immunosuppressive medication.

Conclusion

¹⁸F-FDG PET is a sensitive and specific imaging tool for large vessel vasculitis, especially when performed in patients not receiving immunosuppressive drugs. It increases the overall diagnostic accuracy and has an impact on the clinical management in a significant proportion of patients.     

Speeding up PET/MR for cancer staging of children and young adults

Objective

Combining ¹⁸F-FDG PET with whole-body MR for paediatric cancer staging is practically feasible if imaging protocols can be streamlined. We compared ¹⁸F-FDG PET/STIR with accelerated ¹⁸F-FDG PET/FSPGR for whole-body tumour imaging in children and young adults.

Methods

Thirty-three children and young adults (17.5?±?5.5 years, range 10–30) with malignant lymphoma or sarcoma underwent a ¹⁸F-FDG PET staging examination, followed by ferumoxytol-enhanced STIR and FSPGR whole-body MR. ¹⁸F-FDG PET scans were fused with MR data and the number and location of tumours on each integrated examination were determined. Histopathology and follow-up imaging served as standard of reference. The agreement of each MR sequence with the reference and whole-body imaging times were compared using Cohen’s kappa coefficient and Student’s t-test, respectively.

Results

Comparing ¹⁸F-FDG PET/FSPGR to ¹⁸F-FDG PET/STIR, sensitivities were 99.3 % for both, specificities were statistically equivalent, 99.8 versus 99.9 %, and the agreement with the reference based on Cohen’s kappa coefficient was also statistically equivalent, 0.989 versus 0.992. However, the total scan-time for accelerated FSPGR of 19.8?±?5.3 minutes was significantly shorter compared to 29.0?±?7.6 minutes for STIR (p?=?0.001).

Conclusion

F-FDG PET/FSPGR demonstrated equivalent sensitivities and specificities for cancer staging compared to ¹⁸F-FDG PET/STIR, but could be acquired with shorter acquisition time.

Key Points

? Breath-hold FSPGR sequences shorten the data acquisition time for whole-body MR and PET/MR.? Ferumoxytol provides long-lasting vascular contrast for whole-body MR and PET/MR.? ¹⁸ F-FDG PET/FSPGR data provided equal sensitivity and specificity for cancer staging compared to ¹⁸ F-FDG PET/STIR.

     

PET/CT comparing <Superscript>68</Superscript>Ga-DOTATATE and other radiopharmaceuticals and in comparison with CT/MRI for the localization of sporadic metastatic pheochromocytoma and paraganglioma

Purpose

Pheochromocytomas/paragangliomas (PPGLs) and their metastases are tumors that predominantly express somatostatin receptor 2 (SSR2). ⁶⁸Ga-DOTA(0)-Tyr(3)-octreotate (⁶⁸Ga-DOTATATE) is a PET radiopharmaceutical with both high and selective affinity for SSRs. The purpose of this study was to evaluate the utility of ⁶⁸Ga-DOTATATE in comparison with other specific and nonspecific radiopharmaceuticals recommended in the current guidelines for the localization of metastatic sporadic PPGL by PET/CT.

Methods

This prospective study included 22 patients (15 men, 7 women; aged 50.0?±?13.9 years) with confirmed metastatic PPGL, a negative family history for PPGL, and negative genetic testing, who underwent ⁶⁸Ga-DOTATATE, ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/CT, and CT/MRI. Only 12 patients underwent an additional ¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) PET/CT scan and only 11 patients underwent an additional ¹⁸F-fluorodopamine (¹⁸F-FDA) PET/CT scan. The rates of detection of metastatic lesions were compared among all the imaging studies. A composite of all functional and anatomical imaging studies served as the imaging comparator.

Results

⁶⁸Ga-DOTATATE PET/CT showed a lesion-based detection rate of 97.6 % (95 % confidence interval, CI, 95.8 – 98.7 %). ¹⁸F-FDG PET/CT, ¹⁸F-FDOPA PET/CT, ¹⁸F-FDA PET/CT, and CT/MRI showed detection rates of 49.2 % (CI 44.5 – 53.6 %; p?<?0.01), 74.8 % (CI 69.0 – 79.9 %); p?<?0.01), 77.7 % (CI 71.5 – 82.8 %; p?<?0.01), and 81.6 % (CI 77.8 – 84.8 %; p?<?0.01), respectively.

Conclusion

The results of this study demonstrate the superiority of ⁶⁸Ga-DOTATATE PET/CT in the localization of sporadic metastatic PPGLs compared to all other functional and anatomical imaging modalities, and suggest modification of future guidelines towards this new imaging modality.

     

FDG PET/CT for the detection of bone marrow involvement in diffuse large B-cell lymphoma: systematic review and meta-analysis

Purpose

To systematically review and meta-analyse published data on the diagnostic performance of ¹⁸F-FDG PET/CT in detecting bone marrow involvement in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL).

Methods

PubMed/MEDLINE and Embase were systematically searched for relevant studies. The methodological quality of each study was assessed. Sensitivities and specificities of FDG PET/CT in individual studies were calculated and meta-analysed with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. Weighted summary proportions of discrepancies between the FDG PET/CT and (blind) bone marrow biopsy (BMB) results among all patients were calculated.

Results

Seven studies, with a total of 654 patients with newly diagnosed DLBCL, were included. Overall, the quality of the included studies was moderate. The sensitivity and specificity of FDG PET/CT for detecting bone marrow involvement ranged from 70.8 % to 95.8 % and from 99.0 % to 100 %, with pooled estimates of 88.7 % (95 % confidence interval, CI, 82.5 – 93.3 %) and 99.8 % (95 % CI 98.8 – 100 %), respectively. The area under the sROC curve was 0.9983. The weighted summary proportion of FDG PET/CT-negative patients with positive BMB findings among all patients was 3.1 % (95 % CI 1.8 – 5.0 %) and the weighted summary proportion of FDG PET/CT-positive patients with negative BMB findings among all patients was 12.5 % (95 % CI 8.4 – 17.3 %).

Conclusion

FDG PET/CT is accurate and complementary to BMB for detecting bone marrow involvement in patients with newly diagnosed DLBCL. A negative FDG PET/CT scan cannot rule out the presence of bone marrow involvement, but positive FDG PET/CT findings obviate the need for BMB for the detection of bone marrow involvement in these patients.     

Performance of 18F-FDG PET/CT as a postoperative surveillance imaging modality for asymptomatic advanced gastric cancer patients

Objective

The purpose of this study was to investigate the diagnostic performance of postoperative fluorine-18 fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) as a surveillance modality for advanced gastric cancer patients who were asymptomatic and negative by conventional follow-up.

Methods

We retrospectively collected 46 advanced gastric cancer patients who received approximately 1-year-postoperative ¹⁸F-FDG PET/CT surveillance following curative resection (mean age 60.6 ± 11.5 years). ¹⁸F-FDG PET/CT was interpreted by nuclear medicine physicians who were blind to the clinical information. Final confirmation was determined by clinical follow-up using tumor markers, conventional CT scan, upper gastrointestinal endoscopy and with/without subsequent histopathologic diagnosis.

Results

Four patients developed recurrence (8.7 %; 1 local and 3 distant recurrences). For local recurrence, ¹⁸F-FDG PET/CT found four hypermetabolic lesions and one was local recurrence. For distant recurrence, seven hypermetabolic lesions were found in six patients and true-positive was three lesions. False-positive cases were mainly turned out to be physiologic small bowel uptake. Regardless of the recurrence site, the sensitivity, specificity, positive predictive value and negative predictive value of ¹⁸F-FDG PET/CT were 100 % (4/4, 95 % confidence interval (CI) 39.6–100 %), 88.1 % (37/42, 95 % CI 73.6–95.5 %), 44.4 % (4/9, 95 % CI 15.3–77.3 %) and 100 % (37/37, 95 % CI 88.3–100 %), respectively in the patient-based analysis.

Conclusion

Our study showed good specificity of postoperative surveillance ¹⁸F-FDG PET/CT for detecting recurrence. Careful caution should be made for interpreting some false-positive hypermetabolic lesions in postoperative ¹⁸F-FDG PET/CT, especially at the local anastomosis site.