Search

The diagnostic accuracy of up-front 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for detecting cervical lymph node metastases in patients with T1–T2 oral squamous cell carcinoma is reported with large discrepancies across the literature. We investigated the sensitivity, specificity, positive and negative predictive value, and accuracy of up-front PET/CT for detecting cervical lymph node metastases in this patient group and compared the performance to magnetic resonance imaging (MRI). In this prospective cohort study, 76 patients with T1–T2 oral squamous cell carcinoma underwent an up-front PET/CT and MRI at the Odense University Hospital from September 2013 to February 2016. Sentinel node biopsy and elective neck dissection were used for histopathological verification of the imaging modalities. Up-front PET/CT was significantly more sensitive than neck MRI (74% vs. 27%, p = 0.0001), but less specific (60% vs. 88%, p = 0.001). The accuracy of PET/CT and neck MRI was comparable (66% vs. 63%, p = 0.85), the PPV was slightly in favor of neck MRI (56% vs. 62%, p = 0.73), the NPV was slightly in favor of PET/CT (77% vs. 63%, p = 0.16). Neither PET/CT nor neck MRI should stand alone for N-staging T1–T2 oral cavity cancer. [ABSTRACT FROM AUTHOR]

The method of 18F-sodium fluoride (NaF) positron emission tomography/computed tomography (PET/CT) of atherosclerosis was introduced 12 years ago. This approach is particularly interesting because it demonstrates microcalcification as an incipient sign of atherosclerosis before the development of arterial wall macrocalcification detectable by CT. However, this method has not yet found its place in the clinical routine. The more exact association between NaF uptake and future arterial calcification is not fully understood, and it remains unclear to what extent NaF-PET may replace or significantly improve clinical cardiovascular risk scoring. The first 10 years of publications in the field were characterized by heterogeneity at multiple levels, and it is not clear how the method may contribute to triage and management of patients with atherosclerosis, including monitoring effects of anti-atherosclerosis intervention. The present review summarizes findings from the recent 2¾ years including the ability of NaF-PET imaging to assess disease progress and evaluate response to treatment. Despite valuable new information, pertinent questions remain unanswered, not least due to a pronounced lack of standardization within the field and of well-designed long-term studies illuminating the natural history of atherosclerosis and effects of intervention. [ABSTRACT FROM AUTHOR]

Background: Artificial intelligence (AI) is known to provide effective means to accelerate and facilitate clinical and research processes. So in this study it was aimed to compare a AI-based method for cardiac segmentation in positron emission tomography/computed tomography (PET/CT) scans with manual segmentation to assess global cardiac atherosclerosis burden. Methods: A trained convolutional neural network (CNN) was used for cardiac segmentation in 18F-sodium fluoride PET/CT scans of 29 healthy volunteers and 20 angina pectoris patients and compared with manual segmentation. Parameters for segmented volume (Vol) and mean, maximal, and total standardized uptake values (SUVmean, SUVmax, SUVtotal) were analyzed by Bland-Altman Limits of Agreement. Repeatability with AI-based assessment of the same scans is 100%. Repeatability (same conditions, same operator) and reproducibility (same conditions, two different operators) of manual segmentation was examined by re-segmentation in 25 randomly selected scans. Results: Mean (± SD) values with manual vs. CNN-based segmentation were Vol 617.65 ± 154.99 mL vs 625.26 ± 153.55 mL (P =.21), SUVmean 0.69 ± 0.15 vs 0.69 ± 0.15 (P =.26), SUVmax 2.68 ± 0.86 vs 2.77 ± 1.05 (P =.34), and SUVtotal 425.51 ± 138.93 vs 427.91 ± 132.68 (P =.62). Limits of agreement were − 89.42 to 74.2, − 0.02 to 0.02, − 1.52 to 1.32, and − 68.02 to 63.21, respectively. Manual segmentation lasted typically 30 minutes vs about one minute with the CNN-based approach. The maximal deviation at manual re-segmentation was for the four parameters 0% to 0.5% with the same and 0% to 1% with different operators. Conclusion: The CNN-based method was faster and provided values for Vol, SUVmean, SUVmax, and SUVtotal comparable to the manually obtained ones. This AI-based segmentation approach appears to offer a more reproducible and much faster substitute for slow and cumbersome manual segmentation of the heart. [ABSTRACT FROM AUTHOR]

Purpose: Suspected serious disease (SSD) is a disease designation often given to patients with one or more non-specific symptoms of severe disease that could be due to cancer; the optimal diagnostic strategy is largely left to the clinician's discretion. Being a sensitive non-invasive whole-body imaging modality 18F-FDG-PET/CT may have a potential role in this cancer-prevalent group of patients to confirm or refute suspected malignancy. We aimed to investigate the diagnostic value of 18F-FDG-PET/CT in SSD using long-term follow-up as reference.Methods: We retrospectively studied results obtained in all SSD patients referred for 18F-FDG-PET/CT at a single institution in 2010-2011 retrieving the following clinical data in all patients: journal entries, examinations, and evaluations made from 6 months before the scan and until the latest recorded entry. A true positive PET scan was a positive scan with a subsequently biopsy-confirmed diagnosis of cancer in the same target organ, whereas a false positive scan had no subsequent cancer diagnosis. A true negative PET scan was a negative scan without a cancer diagnosis during follow-up, whereas a false negative PET scan was one with a subsequently confirmed cancer diagnosis.Results: Ninety-three patients, aged 67 years (range 25-89) were included and followed for up to 7.3 years (median 6). Of these, 21 [22.6% (95% CI 15.3-32.1)] turned out to have cancer. With 18F-FDG-PET/CT, the sensitivity was 81.0% (95% CI 60.0-92.3), specificity 76.4% (95% CI 65.4-84.7), positive predictive value 50% (95% CI 34.1-65.9), and negative predictive value 93.2% (95% CI 83.8-97.3). Five patients with negative scans were subsequently diagnosed with cancer.Conclusion: Cancer prevalence is substantial among patients with SSD. 18F-FDG-PET/CT is a promising option in this setting, in particular because a high negative predictive value equals a low incidence of cancer during follow-up. Further studies are needed to establish the role of 18F-FDG-PET/CT in SSD. [ABSTRACT FROM AUTHOR]

Objective To compare the diagnostic accuracy of the following imaging techniques in the detection of spine metastases, using magnetic resonance imaging ( MRI) as a reference: whole-body bone scintigraphy ( WBS) with technetium-99m- MDP, [18 F]-sodium fluoride ( NaF) positron emission tomography ( PET)/computed tomography ( CT) and [18 F]-fluoromethylcholine ( FCH) PET/ CT. Patients and Methods The study entry criteria were biopsy-proven prostate cancer, a positive WBS consistent with bone metastases, and no history of androgen deprivation. Within 30 days of informed consent, trial scans were performed in random order. Scans were interpreted blindly for the purpose of a lesion-based analysis. The primary target variable was bone lesion (malignant/benign) and the 'gold standard' was MRI. Results A total of 50 men were recruited between May 2009 and March 2012. Their mean age was 73 years, their median PSA level was 84 ng/mL, and the mean Gleason score of the tumours was 7.7. A total of 46 patients underwent all four scans, while four missed one PET/ CT scan. A total of 526 bone lesions were found in the 50 men: 363 malignant and 163 non-malignant according to MRI. Sensitivity, specificity, positive and negative predictive values and accuracy were: WBS: 51, 82, 86, 43 and 61%; NaF- PET/ CT: 93, 54, 82, 78 and 81%; and FCH-PET/ CT: 85, 91, 95, 75 and 87%, respectively. Conclusions We found that FCH-PET/ CT and NaF- PET/ CT were superior to WBS with regard to detection of prostate cancer bone metastases within the spine. The present results call into question the use of WBS as the method of choice in patients with hormone-naïve prostate cancer. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the prognostic value of clinician interpretation of positron emission tomography/computed tomography (PET/CT) reports at mid-therapy, interim PET (I-PET) and after the end of first-line therapy (E-PET) in patients with diffuse large B-cell lymphoma (DLBCL). Four hundred and thirty patients were enrolled in this study comprising a total of 617 PET reports. Each report was evaluated by three expert hematologists randomly selected from a panel of nine. Reports were labeled positive or negative if all three interpreters agreed. All others were considered indeterminate. Indeterminate reports accounted for 59% of I-PET and 49% of E-PET reports. Two-year overall survival (OS) for patients with a positive, indeterminate and negative I-PET was 58%, 87% and 89% ( p < 0.001), respectively. Two-year OS for patients with E-PET was 41%, 89% and 97% ( p < 0.001) for positive, indeterminate and negative interpretation of PET/CT reports. Progression-free survival and OS did not differ significantly in patients with a negative and an indeterminate I-PET report. The use of well-defined reporting criteria, e.g. the Deauville five-point scale, is likely to reduce the number of scans perceived as indeterminate. [ABSTRACT FROM AUTHOR]

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 O-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. [ABSTRACT FROM AUTHOR]

Study Type - Diagnostic (exploratory cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Staging of patients with prostate cancer is the cornerstone of treatment. However, after curative intended therapy a high portion of patients relapse with local and/or distant recurrence. Therefore, one may question whether surgical lymph node dissection (LND) is sufficiently reliable for staging of these patients. Several imaging methods for primary LN staging of patients with prostate cancer have been tested. Acceptable detection rates have not been achieved by CT or MRI or for that matter with PET/CT using the most common tracer fluoromethylcholine (FCH). Other more recent metabolic tracers like acetate and choline seem to be more sensitive for assessment of LNs in both primary staging and re-staging. However, previous studies were small. Therefore, we assessed the value of [18F]FCH PET/CT for primary LN staging in a prospective study of a larger sample and with a 'blinded' review. After a study period of 3 years and >200 included patients, we concluded that [18F]FCH PET/CT did not reach an optimal detection rate compared with LND, and, therefore, it cannot replace this procedure. However, we did detect several bone metastases with [18F]FCH PET/CT that the normal bone scans had missed, and this might be worth pursuing. OBJECTIVES To assess the value of [18F]fluoromethylcholine (FCH) positron emission tomography/computed tomography (PET/CT) for lymph node (LN) staging of prostate cancer., To evaluate if FCH PET/CT can replace LN dissection (LND) for LN staging of prostate cancer, as about one-third of patients with prostate cancer who receive intended curative therapy will have recurrence, one reason being undetected LN involvement., PATIENTS AND METHODS From January 2008 to December 2010, 210 intermediate- or high-risk patients had a FCH PET/CT scan before regional LND., After dissection, the result of histological examination of the LNs (gold standard) was compared with the result of FCH PET/CT obtained by 'blinded review'., Sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of FCH PET/CT were measured for detection of LNe metastases., RESULTS Of the 210 patients, 76 (36.2%) were in the intermediate-risk group and 134 (63.8%) were in the high-risk group. A medium (range) of 5 (1-28) LNs were removed per patient., Histological examination of removed LNs showed metastases in 41 patients. Sensitivity, specificity, PPV, and NPV of FCH PET/CT for patient-based LN staging were 73.2%, 87.6%, 58.8% and 93.1%, respectively., Corresponding values for LN-based analyses were 56.2%, 94.0%, 40.2%, and 96.8%, respectively., The mean diameter of the true positive LN metastases was significantly larger than that of the false negative LNs (10.3 vs 4.6 mm; P < 0.001)., In addition, FCH PET/CT detected a high focal bone uptake, consistent with bone metastases, in 18 patients, 12 of which had histologically benign LNs., CONCLUSIONS Due to a relatively low sensitivity and a correspondingly rather low PPV, FCH PET/CT is not ideal for primary LN staging in patients with prostate cancer., However, FCH PET/CT does convey important additional information otherwise not recognised, especially for bone metastases. [ABSTRACT FROM AUTHOR]

Study Type – Diagnostic (case series) Level of Evidence 4 OBJECTIVES To evaluate prospectively [18F]-fluorocholine positron-emission/computed tomography (FCH PET/CT) for lymph node staging of prostate cancer before intended curative therapy, and to determine whether imaging 15 or 60 min after radiotracer injection is preferable. PATIENTS AND METHODS In all, 25 consecutive patients with newly diagnosed prostate cancer (Gleason score >6, and/or a prostate-specific antigen level of >10 ng/mL, and/or T3 cancer) were scanned before lymphadenectomy. Each patient was assessed twice with imaging, at 15 and 60 min after the injection with FCH. Images were compared with the results of histopathological examination of the surgically removed lymph nodes. Maximum standardized uptake values (SUVmax) at 15 and 60 min were also compared. RESULTS Histopathologically, metastases were present in removed lymph nodes from three patients. FCH PET/CT showed a high radiotracer uptake in four patients, the former three and a fourth. The sensitivity, specificity, positive and negative predictive value of FCH PET/CT for patient based lymph node staging of prostate cancer were 100%, 95%, 75% and 100%, respectively; the corresponding 95% confidence intervals were 29.2–100%, 77.2–99.9%, 19.4–99.4% and 83.9–100%, respectively. Values of SUVmax at early and late imaging were not significantly different. CONCLUSIONS This small series supports the use of FCH PET/CT as a tool for lymph node staging of patients with prostate cancer. Values of SUVmax at early and late imaging did not differ. However, larger prospective studies are needed to validate these findings. [ABSTRACT FROM AUTHOR]

Multislice cardiac CT characterizes late stage macrocalcification in epicardial arteries as opposed to PET/CT, which mirrors early phase arterial wall changes in epicardial and transmural coronary arteries. With regard to tracer, there has been a shift from using mainly 18F-fluorodeoxyglucose (FDG), indicating inflammation, to applying predominantly 18F-sodium fluoride (NaF) due to its high affinity for arterial wall microcalcification and more consistent association with cardiovascular risk factors. To make NaF-PET/CT an indispensable adjunct to clinical assessment of cardiac atherosclerosis, the Alavi–Carlsen Calcification Score (ACCS) has been proposed. It constitutes a global assessment of cardiac atherosclerosis burden in the individual patient, supported by an artificial intelligence (AI)-based approach for fast observer-independent segmentation. Common measures for characterizing epicardial coronary atherosclerosis by NaF-PET/CT as the maximum standardized uptake value (SUV) or target-to-background ratio are more versatile, error prone, and less reproducible than the ACCS, which equals the average cardiac SUV. The AI-based approach ensures a quick and easy delineation of the entire heart in 3D to obtain the ACCS expressing ongoing global cardiac atherosclerosis, even before it gives rise to CT-detectable coronary calcification. The quantification of global cardiac atherosclerotic burden by the ACCS is suited for management triage and monitoring of disease progression with and without intervention. [ABSTRACT FROM AUTHOR]

Response evaluation at regular intervals is indicated for treatment of metastatic breast cancer (MBC). FDG-PET/CT has the potential to monitor treatment response accurately. Our purpose was to: (a) compare the interrater agreement and reliability of the semi-quantitative PERCIST criteria to qualitative visual assessment in response evaluation of MBC and (b) investigate the intrarater agreement when comparing visual assessment of each rater to their respective PERCIST assessment. We performed a retrospective study on FDG-PET/CT in women who received treatment for MBC. Three specialists in nuclear medicine categorized response evaluation by qualitative assessment and standardized one-lesion PERCIST assessment. The scans were categorized into complete metabolic response, partial metabolic response, stable metabolic disease, and progressive metabolic disease. 37 patients with 179 scans were included. Visual assessment categorization yielded moderate agreement with an overall proportion of agreement (PoA) between raters of 0.52 (95% CI 0.44–0.66) and a Fleiss kappa estimate of 0.54 (95% CI 0.46–0.62). PERCIST response categorization yielded substantial agreement with an overall PoA of 0.65 (95% CI 0.57–0.73) and a Fleiss kappa estimate of 0.68 (95% CI 0.60–0.75). The difference in PoA between overall estimates for PERCIST and visual assessment was 0.13 (95% CI 0.06–0.21; p = 0.001), that of kappa was 0.14 (95% CI 0.06–0.21; p < 0.001). The overall intrarater PoA was 0.80 (95% CI 0.75–0.84) with substantial agreement by a Fleiss kappa of 0.74 (95% CI 0.69–0.79). Semi-quantitative PERCIST assessment achieved significantly higher level of overall agreement and reliability compared with qualitative assessment among three raters. The achieved high levels of intrarater agreement indicated no obvious conflicting elements between the two methods. PERCIST assessment may, therefore, give more consistent interpretations between raters when using FDG-PET/CT for response evaluation in MBC. [ABSTRACT FROM AUTHOR]

Purpose: To compare multidisciplinary team conference (MDTC) decisions regarding treatment intent based on either chest X-ray + MRI of the head and neck (CXR/MRI) or 18F-FDG-PET/CT (PET/CT) in patients with recurrent head and neck squamous cell carcinoma (HNSCC).Methods: Prospective blinded cohort study based on paired data. Consecutive patients with suspected recurrent HNSCC were invited to participate. All included patients underwent CXR/MRI and PET/CT before diagnostic biopsy. An ordinary MDTC using all available imaging data was conducted as per standard practice. After at least three months (to eliminate recall bias in the team), the first project MDTC, based on either CXR/MRI or PET/CT, was conducted, and the tumor board made conclusions regarding treatment. After an additional three months, a second project MDTC was conducted using the complementary imaging strategy. The separate treatment strategies were compared using McNemar's test.Results: A total of 110 patients (90 males and 20 females, median age 66 years, range 40-87) were included. The initial primary tumor originated from the pharynx in 56 (51%) patients, oral cavity in 17 (15%) patients, and larynx in 37 (34%) patients. Based on CXR/MRI, 87 patients (79%) were recommended curative treatment and 23 (21%) palliative treatment. Based on PET/CT, the MDTC decided that 52 (47%) patients were suitable for curative treatment and 58 (53%) for palliative treatment. The absolute difference of 32% was statistically significant (95% CI: 22-42%, p < 0.001).Conclusions: PET/CT affected MDTC decisions in patients with recurrent HNSCC towards less curative and more palliative treatment. [ABSTRACT FROM AUTHOR]

18F-fluoro-deoxy-glucose-positron emission tomography/computed tomography-scan (PET/CT) is used increasingly for detection of cancer. Precise diagnostic assessment of tumour extension in head and neck squamous cell carcinoma (HNSCC) is of critical importance for ensuring that patients receive proper treatment. Preliminary studies have shown divergent results of PET/CT in diagnosis and staging of HNSCC. The aims of this study were (1) to systematically review and meta-analyse published data about the diagnostic accuracy of PET/CT for diagnosing patients with HNSCC and (2) to compare the diagnostic accuracy of PET/CT with that of standard conventional imaging (SCI). Methods A systematic literature search in the PubMed, Embase and Cochrane databases on publications of PET/CT diagnostics of HNSCC from January 2005 to July 2013 was carried out. All retrieved studies were reviewed and qualitatively analysed. Along with the calculated pooled sensitivity and specificity of PET/CT and SCI, bubble- and summary receiver operating characteristics (SROC) plots were created. Findings Two meta-analyses of diagnostic accuracy were conducted. The first, on PET/CT, included 987 patients distributed across nine studies. The second, on SCI, included 517 patients participating in a total of six studies among those comparing PET/CT to SCI. The meta-analyses showed a pooled sensitivity of 89.3% (95% confidence interval [95% CI]: 83.4-93.2%) and specificity of 89.5% (95% CI: 82.9-93.7%) for PET/CT and correspondingly, a pooled sensitivity and specificity of 71.6% (95% CI: 44.3-88.9%) and 78.0% (95%CI: 30.2-96.7%) for SCI. A graphical comparison to SCI showed a clear difference in favour of PET/CT. Interpretation PET/CT is highly accurate in diagnosing patients suffering from HNSCC [ABSTRACT FROM AUTHOR]