<Superscript>18</Superscript>F-FDG-PET/CT for systemic staging of newly diagnosed triple-negative breast cancer

Purpose

National Comprehensive Cancer Network guidelines recommend ¹⁸F-FDG-PET/CT, in addition to standard staging procedures, for systemic staging of newly diagnosed stage III breast cancer patients. However, factors in addition to stage may influence PET/CT utility. As breast cancers that are negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor (triple-negative breast cancer, or TNBC) are more aggressive and metastasize earlier than other breast cancers, we hypothesized that receptor expression may be one such factor. This study assesses ¹⁸F-FDG-PET/CT for systemic staging of newly diagnosed TNBC.

Methods

In this Institutional Review Board-approved retrospective study, our Healthcare Information System was screened for patients with TNBC who underwent ¹⁸F-FDG-PET/CT in 2007–2013 prior to systemic or radiation therapy. Initial stage was determined from mammography, ultrasound, magnetic resonance imaging, and/or surgery, if performed prior to ¹⁸F-FDG-PET/CT. ¹⁸F-FDG-PET/CT was evaluated to identify unsuspected extra-axillary regional nodal and distant metastases, as well as unsuspected synchronous malignancies. Kaplan Meier survival estimates were calculated for initial stage IIB patients stratified by whether or not stage 4 disease was detected by ¹⁸F-FDG-PET/CT.

Results

A total of 232 patients with TNBC met inclusion criteria. ¹⁸F-FDG-PET/CT revealed unsuspected distant metastases in 30 (13 %): 0/23 initial stage I, 4/82 (5 %) stage IIA, 13/87 (15 %) stage IIB, 4/23 (17 %) stage IIIA, 8/14 (57 %) stage IIIB, and 1/3 (33 %) stage IIIC. Twenty-six of 30 patients upstaged to IV by ¹⁸F-FDG-PET/CT were confirmed by pathology, with the remaining four patients confirmed by follow-up imaging. In addition, seven unsuspected synchronous malignancies were identified in six patients. Initial stage 2B patients who were upstaged to 4 by ¹⁸F-FDG-PET/CT had significantly shorter survival compared to initial stage 2B patients who were not (3-year Kaplan Meier estimate 0.33, 95 % CI 0.13-0.55 versus 0.97, CI 0.76-0.93, p?<?.0001).

Conclusion

F-FDG-PET/CT revealed distant metastases in 15 % of patients with stage IIB TNBC. Stage IIB patients upstaged to 4 by ¹⁸F-FDG-PET/CT had significantly shorter survival than those who were not, consistent with ¹⁸F-FDG-PET/CT detecting an increased burden of disease. This study provides further evidence that populations of patients with stage IIB breast cancer, such as TNBC, should be considered for systemic staging with ¹⁸F-FDG-PET/CT at the time of initial diagnosis.

     

Multimodal imaging with <Superscript>18</Superscript>F-FDG-PET/CT and <Superscript>111</Superscript>In-Octreotide SPECT in patients with metastatic medullary thyroid carcinoma

Objective

The aim of our study was to determine the role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) and indium-111 Octreotide single photon emission tomography (¹¹¹In-Octreotide SPECT) in the evaluation of metastatic medullary thyroid carcinoma (MMTC).

Methods

Twenty-five MMTC patients were retrospectively evaluated. All patients had undergone whole-body ¹⁸F-FDG-PET/CT including 20 who had also undergone ¹¹¹In-Octreotide SPECT within a maximum interval of 6 weeks. Diagnostic contrast-enhanced computed tomography (CT) alone or as part of ¹⁸F-FDG-PET/CT examination was performed in all patients.

Results

Contrast-enhanced CT detected a total of 131 lesions including 79 enlarged lymph nodes and 14 bone lesions. ¹⁸F-FDG-PET/CT visualized a total of 92 true positive lesions (SUV_max range 1.1–10.0, mean 4.0 ± 1.7) including 66 lymph nodes, 7 of which were not enlarged on CT, and 8 bone metastases. In the 20 patients studied with both techniques, a total of 64 and 46 true positive lesions were detected by ¹⁸F-FDG-PET/CT and ¹¹¹In-Octreotide SPECT, respectively. In particular, ¹⁸F-FDG uptake was found in 43 lymph nodes and in 7 bone metastases whereas ¹¹¹In-Octreotide uptake was detected in 27 lymph nodes and in 10 bone metastases.

Conclusions

In MMTC patients, ¹⁸F-FDG-PET/CT provides a useful contribution mainly in evaluating lymph node involvement whereas ¹¹¹In-Octreotide SPECT can contribute to the detection and somatostatin receptor characterization especially of bone lesions.

     

Diagnostic and prognostic value of <Superscript>18</Superscript>F-FDG PET/CT for axillary lymph node staging in patients with breast cancer

Purpose

To investigate the diagnostic and prognostic value of ¹⁸F-FDG-PET/CT for axillary lymph node (LN) staging in breast cancer patients, employing histologic evaluation as the reference.

Methods

Among 196 patients with biopsy-proven breast cancer who had undergone ¹⁸F-FDG-PET/CT before mastectomy or breast-conserving surgery with sentinel LN biopsy and/or axillary LN dissection, 200 axillae were retrospectively analyzed by visual assessment and quantitatively using SUVmax. LN SUVmax as well as other clinicopathological features were assessed for their prognostic value using the log-rank test and Cox method.

Results

Metastasis was diagnosed histopathologically in 56 (28 %) axillae. The sensitivity, specificity, and accuracy of visual PET/CT for diagnosing node metastasis were 55.4, 95.8, and 84.5 %, respectively. When the optimal discriminative SUVmax cutoff was 1.5, these figures were 51.8, 97.2, and 84.5 %, respectively. Fourteen of 55 patients (25.5 %) with LN metastases suffered a recurrence during follow-up (median 39 months). Patients with a high nodal SUVmax (≥1.7) had a significantly lower progression-free survival rate than those with a low SUVmax (p = 0.0499). Axillary nodal and primary tumor SUVmax as well as estrogen receptor status were significantly associated with recurrence.

Conclusion

Axillary nodal SUVmax may be a prognostic indicator of disease recurrence in patients with axillary LN metastases.

     

<Superscript>18</Superscript>F-DOPA PET/CT in the diagnosis and localization of persistent medullary thyroid carcinoma

Purpose

To evaluate the performance of ¹⁸F-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET/CT in the detection of locoregional and distant medullary thyroid carcinoma (MTC) metastases and to compare imaging findings with histological data.

Methods

We retrospectively evaluated 86 MTC patients with persistently high serum calcitonin levels after initial surgery who had undergone ¹⁸F-DOPA PET/CT between January 2007 and December 2014 in two referral centres. They were followed up for at least 6 months after the PET/CT assessment. The results were compared with histological data or with the findings obtained during follow-up using a complementary imaging modality.

Results

¹⁸F-DOPA PET/CT was positive in 65 of the 86 patients, corresponding to a patient-based sensitivity of 75.6 %. Distant metastatic disease (M1) was seen in 29 patients including 11 with previously unknown metastases revealed only by PET/CT. Among the 36 patients without distant metastatic spread, 25 had nodal involvement limited to the neck, and 10 of these 25 patients underwent reoperation. The lymph node compartment-based sensitivity of ¹⁸F-DOPA PET/CT was 100 % in the two institutions but lesion-based sensitivity was only 24 %. Preoperative and postoperative median calcitonin levels were 405 pg/mL (range 128 – 1,960 pg/mL) and 259 pg/mL (range 33 – 1,516 pg/mL), respectively. None of the patients achieved normalization of serum calcitonin after reoperation.

Conclusion

¹⁸F-DOPA PET/CT enables early diagnosis of a significant number of patients with distant metastasis. It has a limited sensitivity in the detection of residual disease but provides high performance for regional analysis. A surgical compartment-oriented approach could be the approach of choice whatever the number of nodes revealed by ¹⁸F-DOPA PET/CT.

     

Detection rate of PET/CT in patients with biochemical relapse of prostate cancer using [<Superscript>68</Superscript>Ga]PSMA I&amp;T and comparison with published data of [<Superscript>68</Superscript>Ga]PSMA HBED-CC

Purpose

To determine the detection rate of PET/CT in biochemical relapse of prostate cancer using [⁶⁸Ga]PSMA I&T and to compare it with published detection rates of [⁶⁸Ga]PSMA HBED-CC.

Methods

We performed a retrospective analysis in 83 consecutive patients with documented biochemical relapse after prostatectomy. All patients underwent whole body [⁶⁸Ga]PSMA I&T PET/CT. PET/CT images were evaluated for presence of local recurrence, lymph node metastases, and distant metastases. Proportions of positive PET/CT results were calculated for six subgroups with increasing prostate specific antigen (PSA) levels (<0.5 ng/mL, 0.5 to <1.0 ng/mL, 1.0 to <2.0 ng/mL, 2.0 to <5.0 ng/mL, 5.0 to <10.0, ≥10.0 ng/mL). Detection rates of [⁶⁸Ga]PSMA I&T were statistically compared with published detection rates of [⁶⁸Ga]PSMA HBED-CC using exact Fisher’s test.

Results

Median PSA was 0.81 (range: 0.01 – 128) ng/mL. In 58/83 patients (70 %) at least one [⁶⁸Ga]PSMA I&T positive lesion was detected. Local recurrent cancer was present in 18 patients (22 %), lymph node metastases in 29 patients (35 %), and distant metastases in 15 patients (18 %). The tumor detection rate was positively correlated with PSA levels, resulting in detection rates of 52 % (<0.5 ng/mL), 55 % (0.5 to <1.0 ng/mL), 70 % (1.0 to <2.0 ng/mL), 93 % (2.0 to <5.0 ng/mL), 100 % (5.0 to <10.0 ng/mL), and 100 % (≥10.0 ng/mL). There was no significant difference between the detection rate of [⁶⁸Ga]PSMA I&T and published detection rates of [⁶⁸Ga]PSMA HBED-CC (all

Conclusions

[⁶⁸Ga]PSMA I&T PET/CT has high detection rates of recurrent prostate cancer that are comparable to [⁶⁸Ga]PSMA HBED-CC.

     

Compared to <Superscript>123</Superscript>I-MIBG SPECT/CT, <Superscript>18</Superscript>F-DOPA PET/CT provides accurate tumor extent in patients with extra-adrenal paraganglioma

Aim

The aim of this study was to compare the accuracy of ¹²³I-MIBG SPECT/CT with that of ¹⁸F-DOPA PET/CT for staging extra-adrenal paragangliomas (PGLs) using both functional and anatomical images (i.e., combined cross-sectional imaging) as the reference standards.

Methods

Three men and seven women (age range 26–73 years) with anatomical and/or histologically proven disease were included in this study. Three patients had either metastatic head-and-neck paragangliomas (HNPGLs) or multifocal PGL, and seven patients had nonmetastatic disease. Comparative evaluation included morphological imaging with CT, functional imaging with ¹⁸F-DOPA PET, and ¹²³I-MIBG imaging including SPECT/CT. Imaging results were analyzed on a per-patient and per-lesion basis.

Results

On a per-patient basis, ¹⁸F-DOPA PET’s detection rate for both nonmetastatic and metastatic/multifocal disease was 100%, whereas that of planar ¹²³I-MIBG imaging alone was 10.0% and that of ¹²³I-MIBG SPECT/CT was 20.0%. Overall, on a per-lesion basis, ¹⁸F-DOPA PET showed a sensitivity of 69.2% (McNemar p?<?0.001) compared with anatomical imaging. Sensitivity of planar ¹²³I-MIBG scintigraphy was 5.6%, and that of SPECT/CT was 11.1% (McNemar p?<?0.0001). Overall, ¹⁸F-DOPA PET identified 18 lesions, and anatomical imaging identified 26 lesions; planar ¹²³IMIBG imaging identified only 1 lesion, and SPECT/CT, 2 lesions.

Conclusion

¹⁸F-DOPA PET is more sensitive than is ¹²³I-MIBG imaging, including SPECT/CT, for staging HNPGL. Combined functional and anatomical imaging (PET/CT) is indicated to exclude metastatic disease in extra-adrenal PGL.

     

Head-to-head comparison between <Superscript>18</Superscript>F-FDOPA PET/CT and MR/CT angiography in clinically recurrent head and neck paragangliomas

Purpose

Head and neck paragangliomas (HNPGLs) can relapse after primary treatment. Optimal imaging protocols have not yet been established for posttreatment evaluation. The aim of the present study was to assess the diagnostic value of ¹⁸F-FDOPA PET/CT and MR/CT angiography (MRA/CTA) in HNPGL patients with clinical relapse during their follow-up.

Methods

Sixteen consecutive patients presenting with local pain, tinnitus, dysphagia, hoarse voice, cranial nerve involvement, deafness, or retrotympanic mass appearing during follow-up after the initial treatment of HNPGLs were retrospectively evaluated. Patients underwent both ¹⁸F-FDOPA PET/CT and MRA (15 patents) or CTA (1 patent). Both methods were first assessed under blinded conditions and afterwards correlated. Head and neck imaging abnormalities without histological confirmation were considered true-positive results based on a consensus between radiologists and nuclear physicians and on further ¹⁸F-FDOPA PET/CT and/or MRA.

Results

¹⁸F-FDOPA PET/CT and MRA/CTA were concordant in 14 patients and in disagreement in 2 patients. ¹⁸F-FDOPA PET/CT and MRA/CTA identified, respectively, 12 and 10 presumed recurrent HNPGLs in 12 patients. The two lesions diagnosed by PET/CT only were confirmed during follow-up by otoscopic examination and MRA performed 29 and 17 months later. ¹⁸F-FDOPA PET/CT images were only slightly influenced by the posttreatment sequelae, showing a better interobserver reproducibility than MRA/CTA. Finally, in 2 of the 16 studied patients, ¹⁸F-FDOPA PET/CT detected two additional synchronous primary HNPGLs.

Conclusion

¹⁸F-FDOPA PET/CT is highly sensitive in posttreatment evaluation of patients with HNPGLs, and also offers better interobserver reproducibility than MRA/CTA and whole-body examination. We therefore suggest that ¹⁸F-FDOPA PET/CT is performed as the first diagnostic imaging modality in symptomatic patients with suspicion of HNPGL relapse after primary treatment when ⁶⁸Ga-labeled somatostatin analogues are not available.

     

<Superscript>68</Superscript>Ga-PSMA-HBED-CC PET imaging in breast carcinoma patients

Background

To report on imaging findings using ⁶⁸Ga-PSMA-HBED-CC PET in a series of 19 breast carcinoma patients.

Methods

⁶⁸Ga-PSMA-HBED-CC PET imaging results obtained were compared to routinely performed staging examinations and analyzed as to lesion location and progesterone receptor status.

Results

Out of 81 tumor lesions identified, 84% were identified on ⁶⁸Ga-PSMA-HBED-CC PET. ⁶⁸Ga-PSMA-HBED-CC SUVmean values of distant metastases proved significantly higher (mean, 6.86, SD, 5.68) when compared to those of primary or local recurrences (mean, 2.45, SD, 2.55, p?=?0.04) or involved lymph nodes (mean, 3.18, SD, 1.79, p?=?0.011). SUVmean values of progesterone receptor-positive lesions proved not significantly different from progesterone receptor-negative lesions. SUV values derived from FDG PET/CT, available in seven patients, and ⁶⁸Ga-PSMA-HBED-CC PET/CT imaging proved weakly correlated (r?=?0.407, p?=?0.015).

Conclusions

⁶⁸Ga-PSMA-HBED-CC PET/CT imaging in breast carcinoma confirms the reported considerable variation of PSMA expression on human solid tumors using immunohistochemistry.

     

Pulmonary <Superscript>18</Superscript>F-FDG uptake helps refine current risk stratification in idiopathic pulmonary fibrosis (IPF)

Purpose

There is a lack of prognostic biomarkers in idiopathic pulmonary fibrosis (IPF) patients. The objective of this study is to investigate the potential of ¹⁸F-FDG-PET/ CT to predict mortality in IPF.

Methods

A total of 113 IPF patients (93 males, 20 females, mean age?±?SD: 70?±?9 years) were prospectively recruited for ¹⁸F-FDG-PET/CT. The overall maximum pulmonary uptake of ¹⁸F-FDG (SUV_max), the minimum pulmonary uptake or background lung activity (SUV_min), and target-to-background (SUV_max/ SUV_min) ratio (TBR) were quantified using routine region-of-interest analysis. Kaplan–Meier analysis was used to identify associations of PET measurements with mortality. We also compared PET associations with IPF mortality with the established GAP (gender age and physiology) scoring system. Cox analysis assessed the independence of the significant PET measurement(s) from GAP score. We investigated synergisms between pulmonary ¹⁸F-FDG-PET measurements and GAP score for risk stratification in IPF patients.

Results

During a mean follow-up of 29 months, there were 54 deaths. The mean TBR?±?SD was 5.6?±?2.7. Mortality was associated with high pulmonary TBR (p?=?0.009), low forced vital capacity (FVC; p?=?0.001), low transfer factor (TLCO; p?<?0.001), high GAP index (p?=?0.003), and high GAP stage (p?=?0.003). Stepwise forward-Wald–Cox analysis revealed that the pulmonary TBR was independent of GAP classification (p?=?0.010). The median survival in IPF patients with a TBR < 4.9 was 71 months, whilst in those with TBR?> 4.9 was 24 months. Combining PET data with GAP data (“PET modified GAP score”) refined the ability to predict mortality.

Conclusions

A high pulmonary TBR is independently associated with increased risk of mortality in IPF patients.

     

<Superscript>68</Superscript>Ga-PSMA PET/CT in patients with recurrent prostate cancer after radical treatment: prospective results in 314 patients

Purpose

We studied the usefulness of ⁶⁸Ga-prostate-specific membrane antigen (PSMA) PET/CT for detecting relapse in a prospective series of patients with biochemical recurrence (BCR) of prostate cancer (PCa) after radical treatment.

Methods

Patients with BCR of PCa after radical surgery and/or radiotherapy with or without androgen-deprivation therapy were included in the study. ⁶⁸Ga-PSMA PET/CT scans performed from the top of the head to the mid-thigh 60 min after intravenous injection of 150?±?50 MBq of ⁶⁸Ga-PSMA were interpreted by two nuclear medicine physicians. The results were correlated with prostate-specific antigen (PSA) levels at the time of the scan (PSApet), PSA doubling time, Gleason score, tumour stage, postsurgery tumour residue, time from primary therapy to BCR, and patient age. When available, ⁶⁸Ga-PSMA PET/CT scans were compared with negative ¹⁸F-choline PET/CT scans routinely performed up to 1 month previously.

Results

From November 2015 to October 2017, 314 PCa patients with BCR were evaluated. Their median age was 70 years (range 44–92 years) and their median PSApet was 0.83 ng/ml (range 0.003–80.0 ng/ml). ⁶⁸Ga-PSMA PET/CT was positive (one or more suspected PCa lesions detected) in 197 patients (62.7%). Lesions limited to the pelvis, i.e. the prostate/prostate bed and/or pelvic lymph nodes (LNs), were detected in 117 patients (59.4%). At least one distant lesion (LNs, bone, other organs, separately or combined with local lesions) was detected in 80 patients (40.6%). PSApet was higher in PET-positive than in PET-negative patients (P?<?0.0001). Of 88 patients negative on choline PET/CT scans, 59 (67%) were positive on ⁶⁸Ga-PSMA PET/CT.

Conclusion

We confirmed the value of ⁶⁸Ga-PSMA PET/CT in restaging PCa patients with BCR, highlighting its superior performance and safety compared with choline PET/CT. Higher PSApet was associated with a higher relapse detection rate.

     

Diagnostic Value of <Superscript>18</Superscript>F-FDG PET/CT and MRI in the Preoperative Evaluation of Uterine Carcinosarcoma

Purpose

This study aimed to compare the diagnostic value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and magnetic resonance imaging (MRI) in the preoperative evaluation of uterine carcinosarcoma.

Methods

Fifty-four women with pathologically confirmed uterine carcinosarcoma who underwent preoperative FDG PET/CT and MRI from June 2006 to November 2016 were included. Pathologic findings from primary tumor lesions, para-aortic and pelvic lymph node (LN) areas, and peritoneal seeding lesions were compared with the FDG PET/CT and MRI findings. The maximum standardized uptake value (SUVmax) of the primary tumor and LN was obtained. The tumor-to-liver ratio (TLR) was calculated by dividing the SUVmax of the primary tumor or LN by the mean SUV of the liver.

Results

For detecting primary tumor lesions (n?=?54), the sensitivity and accuracy of FDG PET/CT (53/54) and MRI (53/54) were 98.2%. The sensitivity, specificity, and accuracy of FDG PET/CT versus MRI were as follows: 63.2% (12/19) versus 26.3% (5/19), 100% (35/35) versus 100% (35/35), and 87.0% versus 74.0%, respectively, for pelvic LN areas (p?=?0.016); 85.7% (12/14) versus 42.9% (6/14), 90% (36/40) versus 97.5% (39/40), and 88.9% versus 83.3%, respectively, for para-aortic LN areas (p?=?0.004); and 59.4% (19/32) versus 50% (16/32), 100% (22/22) versus 100% (22/22), and 75.9% versus 70.4%, respectively, for peritoneal seeding lesions (p?=?0.250). For distant metastasis, the sensitivity, specificity, and accuracy of FDG PET/CT were 100 (8/8), 97.8 (45/46), and 98.2%, respectively.

Conclusions

FDG PET/CT showed superior diagnostic accuracy compared to MRI in detecting pelvic and para-aortic LN metastasis in patients with uterine carcinosarcoma. Moreover, FDG PET/CT facilitated the identification of distant metastasis.

     

Incidental focal <Superscript>18</Superscript>F-FDG uptake in the frontal process of the maxilla on PET/CT: prevalence and clinical significance

Objective

We investigated the prevalence and clinical significance of incidental focal ¹⁸F-FDG uptake in the frontal process of the maxilla, mimicking malignancy on PET/CT.

Methods

From a total of 32,834 patients who underwent ¹⁸F-FDG PET/CT, patients with focal uptake in the frontal process of the maxilla were selected by a database search. For those patients, medical records including relevant imaging studies were reviewed.

Results

Thirty-nine patients (0.12 %) demonstrated focal uptake on PET/CT. On CT of PET/CT, all lesions showed ground-glass attenuation with or without bony expansion, consistent with fibrous dysplasia. When comparing previous PET/CT, follow-up PET/CT, and CT, a significant difference in degree of ¹⁸F-FDG uptake was noted, with no associated change in the size of maxillary lesions. There were no patients who had symptoms or signs related to maxillary lesions during follow-up.

Conclusion

Focal ¹⁸F-FDG uptake in the frontal process of the maxilla is a rare, incidental, and persistent finding with variable uptake and can represent a benign condition.

     

The impact of [<Superscript>68</Superscript>Ga]PSMA I&amp;T PET/CT on radiotherapy planning in patients with prostate cancer

Purpose

To determine the impact of Gallium-68-labled prostate-specific membrane antigen positron-emission tomography/computed tomography ([⁶⁸Ga]PSMA PET/CT) on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.

Methods

A total of 106 patients with prostate cancer scheduled for radiation therapy underwent 120 [⁶⁸Ga]PSMA PET/CT scans prior to radiotherapy treatment. In 20 cases, patients underwent [⁶⁸Ga]PSMA PET/CT for primary therapy (PT), 75 cases were referred for biochemical relapse after surgery (RL), and 25 cases were intended for palliative treatment of localized metastases (MD). We retrospectively compared the impact of [⁶⁸Ga]PSMA PET/CT on lesion detection and treatment decision to CT alone.

Results

[⁶⁸Ga]PSMA PET/CT revealed a total of 271 positive lesions, whereas CT detected 86 lesions (32%). Overall, the radiotherapy regime was changed in 55 of 120 cases (46%) based on the higher detection rate of [⁶⁸Ga]PSMA PET/CT: in 15% of cases with PT, in 43% of cases with RL, and in 44% of cases with MD.

Conclusion

[⁶⁸Ga]PSMA PET/CT is superior to CT alone for lesion detection in prostate cancer, thereby significantly impacting on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.

     

Assessing the role of <Superscript>18</Superscript>F-FDG PET and <Superscript>18</Superscript>F-FDG PET/CT in the diagnosis of soft tissue musculoskeletal malignancies: a systematic review and meta-analysis

Purpose

Twelve years ago a meta-analysis evaluated the diagnostic performance of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in assessing musculoskeletal soft tissue lesions (MsSTL). Currently, PET/CT has substituted PET imaging; however, there has not been any published meta-analysis on the use of PET/CT or a comparison of PET/CT with PET in the diagnosis of MsSTL. Therefore, we conducted a meta-analysis to identify the current diagnostic performance of ¹⁸F-FDG PET/CT and determine if there is added value when compared to PET.

Methods

A systematic review of English articles was conducted, and MEDLINE PubMed, the Cochrane Library, and Embase were searched from 1996 to March 2015. Studies exploring the diagnostic accuracy of ¹⁸F-FDG PET/CT (or dedicated PET) compared to histopathology in patients with MsSTL undergoing investigation for malignancy were included.

Results

Our meta-analysis included 14 articles composed of 755 patients with 757 soft tissue lesions. There were 451 (60 %) malignant tumors and 306 benign lesions. The ¹⁸F-FDG PET/CT (and dedicated PET) mean sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for diagnosing MsSTL were 0.96 (0.90, 1.00), 0.77 (0.67, 0.86), 0.88 (0.85, 0.91), 0.86 (0.78, 0.94), and 0.91 (0.83, 0.99), respectively. The posterior mean (95 % highest posterior density interval) for the AUC was 0.92 (0.88, 0.96). PET/CT had higher specificity, accuracy, and positive predictive value when compared to a dedicated PET (0.85, 0.89, and 0.91 vs 0.71, 0.85, and 0.82, respectively).

Conclusion

¹⁸F-FDG PET/CT and dedicated PET are both highly accurate in the diagnosis of MsSTL. PET/CT is more accurate and specific and has a higher positive predictive value than PET.

     

Prognostic implications of <Superscript>62</Superscript>Cu-diacetyl-bis (<Emphasis Type="Italic">N</Emphasis><Superscript>4</Superscript>-methylthiosemicarbazone) PET/CT in patients with glioma

Objective

The potential of positron emission tomography/computed tomography using ⁶²Cu-diacetyl-bis (N⁴-methylthiosemicarbazone) (⁶²Cu-ATSM PET/CT), which was originally developed as a hypoxic tracer, to predict therapeutic resistance and prognosis has been reported in various cancers. Our purpose was to investigate prognostic value of ⁶²Cu-ATSM PET/CT in patients with glioma, compared to PET/CT using 2-deoxy-2-[¹⁸F]fluoro-d-glucose (¹⁸F-FDG).

Method

56 patients with glioma of World Health Organization grade 2–4 were enrolled. All participants had undergone both ⁶²Cu-ATSM PET/CT and ¹⁸F-FDG PET/CT within mean 33.5 days prior to treatment. Maximum standardized uptake value and tumor/background ratio were calculated within areas of increased radiotracer uptake. The prognostic significance for progression-free survival and overall survival were assessed by log-rank test and Cox’s proportional hazards model.

Results

Disease progression and death were confirmed in 37 and 27 patients in follow-up periods, respectively. In univariate analysis, there was significant difference of both progression-free survival and overall survival in age, tumor grade, history of chemoradiotherapy, maximum standardized uptake value and tumor/background ratio calculated using ⁶²Cu-ATSM PET/CT. Multivariate analysis revealed that maximum standardized uptake value calculated using ⁶²Cu-ATSM PET/CT was an independent predictor of both progression-free survival and overall survival (p?<?0.05). In a subgroup analysis including patients of grade 4 glioma, only the maximum standardized uptake values calculated using ⁶²Cu-ATSM PET/CT showed significant difference of progression-free survival (p?<?0.05).

Conclusions

⁶²Cu-ATSM PET/CT is a more promising imaging method to predict prognosis of patients with glioma compared to ¹⁸F-FDG PET/CT.

     

Diagnostic utility of PET/CT with <Superscript>18</Superscript>F-DOPA and <Superscript>18</Superscript>F-FDG in persistent or recurrent medullary thyroid carcinoma: the importance of calcitonin and carcinoembryonic antigen cutoff

Purpose

This study sought to evaluate and compare the utility of 18-F-fluorodihydroxyphenylalanine (¹⁸F-DOPA) and 18-F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for identification of lesions in patients with recurrent medullary thyroid carcinoma (MTC). In addition, we analyzed the correlation between the calcitonin (Ct), carcinoembryonic antigen (CEA) levels, each doubling time (DT), and PET positivity. We evaluated the reliability of the 150 pg/mL Ct cutoff set by the American Thyroid Association guidelines for further imaging (including ¹⁸F-DOPA PET/CT).

Methods

We prospectively recruited 18 patients with recurrent MTC, identified by elevation of Ct or CEA. Each patient underwent a ¹⁸F-FDG PET/CT and a ¹⁸F-DOPA PET/CT.

Results

Abnormal uptakes were detected with ¹⁸F-DOPA (n=12) and ¹⁸F-FDG (n=9), (sensitivity of 66.7% vs. 50%; p<0.01). Twenty-eight lesions were detected with ¹⁸F-DOPA vs. 16 lesions with ¹⁸F-FDG (1.56±1.5 vs. 0.89±1.18 lesions per patient; p=0.01). None of our patients showed additional lesions with ¹⁸F-FDG in comparison to ¹⁸F-DOPA. Patient-based detection rate increased significantly with Ct levels ≥150 pg/mL vs. Ct<150 pg/mL for both ¹⁸F-DOPA (sensitivity 90.9% vs. 28.6%; p=0.013) and ¹⁸F-FDG PET/CT (sensitivity 72.7% vs. 14.3%; p=0.025). Using a CEA cutoff of ≥5 ng/mL, detection rates of ¹⁸F-DOPA and ¹⁸F-FDG PET/CT were 81.1% and 72.7%, respectively. No correlation between Ct-DT or CEA-DT and PET positivity was found. Histological confirmation was obtained in eight patients.

Conclusions

¹⁸F-DOPA PET/CT appears to be superior to ¹⁸F-FDG PET/CT in detecting and locating lesions in patients with recurrent MTC. This technique tends to be especially useful in patients with negative results in other imaging modalities and Ct≥150 pg/mL or CEA≥5 ng/mL.

     

Diagnostic value of combining <Superscript>11</Superscript>C-choline and <Superscript>18</Superscript>F-FDG PET/CT in hepatocellular carcinoma

Purpose

In this prospective study, our goal was to emphasize the diagnostic value of combining ¹¹C-choline and ¹⁸F-FDG PET/CT for hepatocellular carcinoma (HCC) in patients with chronic liver disease.

Methods

Thirty-three consecutive patients were enrolled. All patients were suspected to have HCC based on CT and/or MRI imaging. A final diagnosis was obtained by histopathological examination or by imaging alone according to American Association for the Study of Liver Disease criteria. All patients underwent PET/CT with both tracers within a median of 5 days. All lesions showing higher tracer uptake than normal liver were considered positive for HCC. We examined how tracer uptake was related to biological (serum α-fetoprotein levels) and pathological (differentiation status, peritumoral capsule and vascular invasion) prognostic markers of HCC, as well as clinical observations at 6 months (recurrence and death).

Results

Twenty-eight HCC, four cholangiocarcinomas and one adenoma were diagnosed. In the HCC patients, the sensitivity of ¹¹C-choline, ¹⁸F-FDG and combined ¹¹C-choline and ¹⁸F-FDG PET/CT for the detection of HCC was 75 %, 36 % and 93 %, respectively. Serum α-fetoprotein levels >200 ng/ml were more frequent among patients with ¹⁸F-FDG-positive lesions than those with ¹⁸F-FDG-negative lesions (p?<?0.05). Early recurrence (n=2) or early death (n=5) occurred more frequently in patients with ¹⁸F-FDG-positive lesions than in those with ¹⁸F-FDG-negative lesions (p?<?0.05).

Conclusion

The combined use of ¹¹C-choline and ¹⁸F-FDG PET/CT detected HCC with high sensitivity. This approach appears to be of potential prognostic value and may facilitate the selection of patients for surgical resection or liver transplantation.

     

Therapy assessment of bone metastatic disease in the era of <Superscript>223</Superscript>radium

Purpose

Defining an optimal imaging modality for assessment of therapy and the best time of evaluation are pivotal for ideal patient’s management.

Methods

²²³Ra (Xofigo®, formerly Alpharadin) has been approved by the FDA and European Medicines Agency for treatment of metastatic castration-resistant prostate cancer with painful osseous involvement.

Results

PET/CT imaging using various radiotracers such as ¹⁸F–FDG, ¹⁸F–FCH, ⁶⁸Ga-PSMA and ¹⁸F–NaF have been investigated to mitigate the limitations of conventional imaging modalities. Diagnostic radiotracers that have properties similar to a therapeutic radiotracer will precisely assess of the possibility and efficacy of a treatment; this is the theranostic concept. An example of a diagnostic test employed for selecting targeted therapy is the combined use of ¹⁸F–fluoride PET/CT for evaluation of possible therapy with ²²³Ra.

Conclusion

This review examines the most recent publications related to this topic.

     

Role of <Superscript>18</Superscript>F-FDG PET/CT in patients affected by Langerhans cell histiocytosis

Purpose

Langerhans cell histiocytosis (LCH) is a rare hematological disorder for which the utility of¹⁸F-FDG PET/CT is unclear. Our aim was to explore the metabolic features of LCH and the possible role of¹⁸F-FDG PET/CT in LCH evaluation.

Materials and methods

We found 17 patients with histologically proven LCH who underwent 17¹⁸F-FDG PET/CT scans for staging and 42 scans for restaging/follow-up purposes. PET/CT results were compared with those obtained from other conventional imaging modalities (bone scintigraphy, plain radiogram, computed tomography, magnetic resonance).

Results

¹⁸F-FDG PET/CT was positive in 15/17 patients, and it detected 36/37 lesions; all bone and extraskeletal lesions, except for a cecal lesion, were¹⁸F-FDG-avid. Only 1/4 of the patients with lung LCH had hypermetabolic lesions. The average SUV_max of the FDG-avid lesions was 7.3 ± 6.7, the average lesion-to-liver SUV_max ratio was 3.4 ± 2.5, and the average lesion-to-blood pool SUV_max ratio was 4 ± 3.2. In comparison to other imaging methods,¹⁸F-FDG PET/CT detected additional lesions or was able to evaluate treatment response earlier in 33/74 cases; it was confirmatory in 38/74 and detected fewer lesions in 3/74 (all three with lung LCH).

Conclusions

¹⁸F-FDG PET/CT seems to be useful for evaluating LCH when compared to conventional imaging, except in pulmonary cases. It can be used both for staging and restaging purposes.

     

Diagnostic performance of <Superscript>18</Superscript>F-FDG PET/CT and whole-body MRI before and early after treatment of multiple myeloma: a prospective comparative study

Objective

To determine the diagnostic accuracy of WB-MRI and ¹⁸F-FDG PET/CT in detecting infiltration pattern, disease activity, and response to treatment in patients with multiple myeloma (MM).

Materials and methods

Fifty-six patients with confirmed MM were included in the present study for pre-treatment evaluation. Among these individuals, 22 patients were available for the post-treatment evaluation of response to therapy. All patients were imaged with both WB-MRI and ¹⁸F-FDG PET/CT. All radiographic findings of infiltration pattern, disease activity, and response to therapy were compared. The diagnostic performance of both modalities was estimated using bone marrow aspirate and biopsy as the reference test.

Results

For detection of active myelomatous tissue at diagnosis, WB-MRI achieved higher sensitivity (94%) than ¹⁸F-FDG PET/CT (75%) (p?=?0.0039), whereas both modalities achieved the same specificity (80%). For detection of residual myelomatous tissue after treatment, ¹⁸F-FDG PET/CT achieved higher specificity (86%) than WB-MRI (43%) (p?=?0.0081), whereas both modalities achieved the same sensitivity (75%).

Conclusion

WB-MRI is more sensitive than ¹⁸F-FDG PET/CT in the diagnosis of MM before treatment; however, ¹⁸F-FDG PET/CT is more specific than WB-MRI in detecting residual involvement in treated patients.