Performance profile of FDG-PET and PET/CT for cancer screening on the basis of a Japanese Nationwide Survey

Deep learning-based PET image denoising and reconstruction: a review

This review focuses on positron emission tomography (PET) imaging algorithms and traces the evolution of PET image reconstruction methods. First, we provide an overview of conventional PET image reconstruction methods from filtered backprojection through to recent iterative PET image reconstruction algorithms, and then review deep learning methods for PET data up to the latest innovations within three main categories. The first category involves post-processing methods for PET image denoising. The second category comprises direct image reconstruction methods that learn mappings from sinograms to the reconstructed images in an end-to-end manner. The third category comprises iterative reconstruction methods that combine conventional iterative image reconstruction with neural-network enhancement. We discuss future perspectives on PET imaging and deep learning technology.

[18F]FDG PET/MRI combined with chest HRCT in early cancer detection: a retrospective study of 3020 asymptomatic subjects

PURPOSE

PET/MRI has become an important medical imaging approach in clinical practice. In this study, we retrospectively investigated the detectability of fluorine-18 (18F)-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging ([18F]FDG PET/MRI) combined with chest computerized tomography (CT) for early cancer in a large cohort of asymptomatic subjects.

METHODS

This study included a total of 3020 asymptomatic subjects who underwent whole-body [18F]FDG PET/MRI and chest HRCT examinations. All subjects received a 2-4-year follow-up for cancer development. Cancer detection rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the [18F]FDG PET/MRI with or without chest HRCT were calculated and analyzed.

RESULTS

Sixty-one subjects were pathologically diagnosed with cancers, among which 59 were correctly detected by [18F]FDG PET/MRI combined with chest HRCT. Of the 59 patients (32 with lung cancer, 9 with breast cancer, 6 with thyroid cancer, 5 with colon cancer, 3 with renal cancer, 1 with prostate cancer, 1 with gastric cancer, 1 with endometrial cancer, and 1 with lymphoma), 54 (91.5%) were at stage 0 or stage I (according to the 8th edition of the tumor-node-metastasis [TNM] staging system), 33 (55.9%) were detected by PET/MRI alone (27 with non-lung cancers and 6 with lung cancer). Cancer detection rate, sensitivity, specificity, PPV, and NPV for PET/MRI combined with chest CT were 2.0%, 96.7%, 99.6%, 83.1%, and 99.9%, respectively. For PET/MRI alone, the metrics were 1.1%, 54.1%, 99.6%, 73.3%, and 99.1%, respectively, and for PET/MRI in non-lung cancers, the metrics were 0.9%, 93.1%, 99.6%, 69.2%, and 99.9%, respectively.

CONCLUSIONS

[18F]FDG PET/MRI holds great promise for the early detection of non-lung cancers, while it seems insufficient for detecting early-stage lung cancers. Chest HRCT can be complementary to whole-body PET/MRI for early cancer detection.

TRIAL REGISTRATION

ChiCTR2200060041. Registered 16 May 2022. Public site: https://www.chictr.org.cn/index.html.

Performance of dedicated breast PET in breast cancer screening: comparison with digital mammography plus digital breast tomosynthesis and ultrasound

OBJECTIVE

To compare the diagnostic performance of dedicated breast positron emission tomography (dbPET) in breast cancer screening with digital mammography plus digital breast tomosynthesis (DM-DBT) and breast ultrasound (US).

METHODS

Women who participated in opportunistic whole-body PET/computed tomography cancer screening programs with breast examinations using dbPET, DM-DBT, and US between 2016-2020, whose results were determined pathologically or by follow-up for at least 1 year, were included. DbPET, DM-DBT, and US assessments were classified into four diagnostic categories: A (no abnormality), B (mild abnormality), C (need for follow-up), and D (recommend further examination). Category D was defined as screening positive. Each modality's recall rate, sensitivity, specificity, and positive predictive value (PPV) were calculated per examination to evaluate their diagnostic performance for breast cancer.

RESULTS

Out of 2156 screenings, 18 breast cancer cases were diagnosed during the follow-up period (10 invasive cancers and eight ductal carcinomas in situ [DCIS]). The recall rates for dbPET, DM-DBT, and US were 17.8%, 19.2%, and 9.4%, respectively. The recall rate of dbPET was highest in the first year and subsequently decreased to 11.4%. dbPET, DM-DBT, and US had sensitivities of 72.2%, 88.9%, and 83.3%; specificities of 82.6%, 81.4%, and 91.2%; and PPVs of 3.4%, 3.9%, and 7.4%, respectively. The sensitivities of dbPET, DM-DBT, and US for invasive cancers were 90%, 100%, and 90%, respectively. There were no significant differences between the modalities. One case of dbPET-false-negative invasive cancer was identified in retrospect. DbPET had 50% sensitivity for DCIS, while that of both DM-DBT and US was 75%. Furthermore, the specificity of dbPET in the first year was the lowest among all periods, and modalities increased over the years to 88.7%. The specificity of dbPET was significantly higher than that of DM-DBT (p < 0.01) in the last 3 years.

CONCLUSIONS

DbPET had a compatible sensitivity to DM-DBT and breast US for invasive breast cancer. The specificity of dbPET was improved and became higher than that of DM-DBT. DbPET may be a feasible screening modality.

The Value of 320-Slice Spiral Computed Tomography Perfusion Imaging in Staging and Long-Term Dynamic Evaluation of Breast Cancer

The value of 320-slice spiral computed tomography (CT) perfusion imaging in staging and long-term dynamic evaluation of breast cancer was explored. 120 breast cancer patients who underwent preoperative CT examination and were confirmed by surgery and pathology were selected. All patients underwent preoperative TNM staging of breast cancer, with 120 cases in each stage. According to the results of 320-slice spiral CT, the postoperative pathology and surgical methods were compared and analyzed. CT diagnosis of breast cancer showed that T1 sensitivity was 71% and accuracy was 61%, T2 sensitivity was 74% and accuracy was 64%, T3 sensitivity was 94% and the accuracy was 84%, and the T4 sensitivity was 100% and the accuracy was 91%. The sensitivity of N1 stage was 71%, and the accuracy was 61%; and the sensitivity of N2 ~ N3 stage was 81%, and the accuracy was 76%. There were 7 cases of M1 with distant metastasis, the sensitivity was 71%, and the accuracy was 71%. At T1 stage, blood flow (BF) was 39.2 ± 16.7 mL/min/100 g, blood volume (BV) was 2.66 ± 1.4 mL/100 g, mean transit time (MTT) was 8.16 ± 2.7 s, and permeability surface (PS) was 16.6 ± 9.7 mL/min/100 g. 320-slice spiral CT perfusion imaging technology provided a new diagnostic mode for everyone, which can quantitatively identify breast cancer with multiple parameters, which was of great significance for clinical auxiliary diagnosis.

Prospective Employer-Initiated Whole-Body Cancer Screening-Costs and Outcomes of a Cancer Screening Program in Japan

PURPOSES

To determine cancer detection and mortality and its costs associated with employee-initiated, prospective whole-body cancer screening program in an engineering company in Hamamatsu, Japan.

MATERIALS AND METHODS

The program includes whole-body fluorine-18-2-fluoro-2-deoxy-D-glucose PET/CT, brain and pelvis MR, and abdominal ultrasound, offered every 2 years five consecutive times. Employees are free to opt in or opt out anytime. The subjects were divided into the full (five consecutive screenings), partial (more than once and less than five), and no participation groups. The rate ratio of cancer detection rate and cancer-related mortality and cancer-related costs of care were measured. All employees also received other annual health screenings, including chest radiograph or upper gastrointestinal study.

RESULTS

Among 1,213 subjects, 543 employees were under full participation, 318 were under partial participation, and 352 were under no participation. In all, 26, 9, and 19 cancers were detected from the full participation, partial participation, and nonparticipation groups, respectively. No statistical significance was observed in the cancer detection rate ratio. The rate ratio of cancer-related deaths was 0.11 (0.01-0.90) for the full participation group compared with the nonparticipation group, and the difference was statistically significant. The cost of cancer-related care was highest among the nonparticipation group; however, the difference was not statistically significant (P = .108).

CONCLUSION

Whole-body cancer screening can successfully reduce cancer-related mortality and costs of cancer-related care. The cancer detection rate was not significantly improved because of broad implementation of additional annual health screenings offered to all employees at no cost, resulting in the high baseline cancer detection rate.

Ten-year prospective evaluation of whole-body cancer screening with multiple modalities including [18F]fluorodeoxyglucose positron emission tomography in a healthy population

PURPOSE

To prospectively evaluate the value of whole-body cancer screening with multiple modalities including FDG-PET in a healthy population.

METHODS

The study was conducted in 1197 healthy individuals aged ≥ 35 years at enrollment between August 2003 and July 2004. All participants were scheduled to receive annual whole-body cancer screening five times (screening period) with subsequent long-term follow-up (follow-up period). The endpoints of the study were definitive cancer diagnosis, cancer-related death, and all-cause death.

RESULTS

The follow-up rate was 99.8% for the screening period and 96.2% for the follow-up period. Forty-five cancers were confirmed during the screening period (August 2003 to July 2009), and 37 of the 45 were detected by the screening. Fourteen of the 45 were PET positive. Sixteen, 5, 4, 9 and 11 cancers were confirmed after the first, the second, the third, the fourth, and the fifth (took 2 years) screening, respectively. Eight participants died, of whom five died of cancer. The rate of cancer incidence (per 100,000) of 628.7 (95% confidence interval [CI] 445.0-812.4) was significantly high, and the rates of cancer mortality and all-cause mortality of 69.9 (95% CI 8.6-131.1) and 111.8 (95% CI 34.3-189.2), respectively, were significantly low, compared with the corresponding rates of 379.3, 138.2 and 354.2, respectively, in the age-rank- and sex-matched general population. During the follow-up period (August 2009 to July 2013), 37 cancers were confirmed and 30 of the 37 were detected. Seven participants died, of whom three died of cancer. The rate of cancer incidence was 809.6 (95% CI 548.7-1070.5). The rates of cancer mortality and all-cause mortality of 65.6 (95% CI 0-139.9) and 153.2 (95% CI 39.7-266.6), respectively, were significantly low compared with 190.1 and 462.3, respectively, in the general population.

CONCLUSION

Cancer detection by PET alone was limited. While the high cancer incidence was attributed to the extensive screening, the low cancer and all-cause mortality may indicate the potential value of this type of cancer screening. Cancer incidence increases with aging and it has been shown that continuous screening may reduce the risk caused by the cancer progression.

Comparison of FDG-PET/CT for Cancer Detection in Populations With Different Risks of Underlying Malignancy

Background/Aim: Whole-body positron-emission tomography/computed tomography with the glucose analog 2-[ 18 F]fluoro-2-deoxy-D-glucose (FDG-PET/CT) has been used to screen examinees for underlying malignancy in many countries. The aim of this study was to compare the potential value of FDG-PET/CT application in asymptomatic individuals with those with suspected malignancy. Patients and Methods: A total of 9,408 examinees underwent whole-body FDG-PET/CT at our hospital from July 2006 to August 2013. Three thousand and seven hundred asymptomatic individuals and 848 individuals with laboratory and clinical/radiologicaI suspicion of malignancy who had undergone FDG-PET/CT for cancer screening were recruited. The final confirmation of cancer and outcomes were based on a pathological report and continuous follow-up. Results: Forty-five out of 3,700 asymptomatic individuals (1.2%) had proven malignancy, and 42 of them (93.3%) were found by FDG-PET/CT. Two hundred and twelve out of 848 with suspected malignancy (25%) had proven malignancy, and 196 of them (92.5%) were detected by FDG-PET/CT. Most of these cancers in asymptomatic individuals were clinically at an early stage. The discovery rate in asymptomatic individuals and those with suspected malignancy was 1.1% and 23.1%, respectively. The overall survival of patients with cancer diagnosed with PET/CT was higher than those with suspected malignancy (78.6% vs. 48.5%, p<0.001). Patients with a resectable lesion, early-stage disease, and lower maximal standardized uptake value had significantly better survival than those without. Conclusion: FDG-PET/CT is useful in the early diagnosis of cancer and thus might improve the survival rates of these patients. Considering the costs and risk of radiation exposure, it would be better used as a priority in patients with laboratory and clinical/radiologic suspicion of malignancy.

The ability of positron emission tomography/computed tomography to detect synchronous colonic cancers in patients with obstructive colorectal cancer

Positron emission tomography/computed tomography (PET/CT) is frequently used to detect colorectal cancer. The present retrospective study assessed the ability of PET/CT to identify synchronous colonic lesions in 72 patients with obstructive colorectal cancer. All patients had undergone surgical resection without undergoing preoperative total colonoscopy (TCS) at the Digestive Disease Center (April 2007 to September 2016), and subsequently underwent TCS of the proximal colon within 2 years post-surgery. A total of 11 patients exhibited 18F-fluorodeoxyglucose uptake during PET/CT of the proximal colon (4 invasive cancers, 3 advanced adenomas and 4 false-positive results), and 61 patients had no uptake in the proximal colon. Among these 61 patients, postoperative TCS revealed 2 invasive cancers and 4 advanced adenomas. The sensitivity of PET/CT for detecting synchronous invasive cancers was 66.6% (4/6), with a specificity of 89.4% (59/66), a positive predictive value of 36.4% (4/11), a negative predictive value of 96.7% (59/61), and an accuracy of 87.5% (63/72). Negative PET/CT results indicated a low probability of synchronous lesions in the proximal colon. Thus, PET/CT may be a useful tool for detecting synchronous colonic cancers in patients with obstructive colon cancer.

Clinical significance of thyroid incidentalomas detected on fluorodeoxyglucose positron emission tomography scan (PETomas): An Indian experience

Thyroid incidentalomas (TIs) are being frequently detected on positron emission tomography (PET) scan. The risk of malignancy in these focal hot spots is substantially high as compared to incidentalomas detected on ultrasonography (USG)/magnetic resonance imaging/computed tomography (CT). Majority of the studies on the prevalence of TIs in PET and the risk of malignancy in them are retrospective and have had varied results. Very few prospective studies are available and very few Indian studies have been done on the subject. Hence, this study was undertaken to evaluate the clinical significance of TIs detected on fluorodeoxyglucose (FDG)-PET scan. The study included all patients undergoing FDG-PET scan for nonthyroid illness from October 2015 to October 2016. Twenty-three consecutive patients detected to have focal TI (FTI) were prospectively evaluated with detailed history and clinical examination, serum thyroid-stimulating hormone, total T4 and total T3 levels, USG neck, fine-needle aspiration cytology (FNAC), and surgery when indicated. The prevalence of FTI was 2.26%. Out of the 23 FTI cases, 19 patients agreed to undergo further evaluation and malignancy was detected in 5 patients (all papillary carcinomas) making a risk of malignancy of 26.3%. There was no significant correlation between CT attenuation characteristics and size of benign and malignant PETomas or between the maximum standardized uptake value (SUV_max) of benign and malignant PETomas. Hence, the risk of malignancy in thyroid PETomas is substantially high and warrants USG-guided FNAC and further work-up. Their SUV_maxvalues, size, and CT attenuation characteristics do not contribute in differentiating benign from malignant lesions.

Cytological evaluation by fine needle aspiration biopsy of incidental focal increased fluorodeoxyglucose uptake in thyroid on positron emission tomography scan

BACKGROUND

With the increased use of whole body fluorodeoxyglucose positron emission tomography (PET) scan for staging/restaging or primary diagnosis of neoplasia, thyroid incidentalomas have become more common. The limited reports of PET-positive thyroid incidentalomas showed incidence of malignancy ranging from 14 to 66%, and there is discrepancy in terms of the diagnostic significance of the standard uptake value (SUV) value.

METHODS

This is a retrospective study of 20 PET incidentalomas which had cytological evaluation from October 2009 to February 2015 at a tertiary care university medical center, M:F = 8:12.

RESULTS

Of the 20 cases, 14 (70%) had a cytological diagnosis of atypia or suspicious for neoplasia. Eleven of those (55%) underwent surgical resection with final diagnosis of PTC in 8 cases, follicular carcinoma in one case (5%), follicular adenoma in one case (5%), and Hurthle cell adenoma in one case (5%). There was good correlation between cytological and histological diagnosis. For two cases with cytological diagnosis of suspicious for follicular neoplasm, no further histological diagnosis was obtained. One patient had direct cytological diagnosis of PTC also did not undergo surgical resection/diagnosis due to the advanced primary pancreatic adenocarcinoma. The remaining 6 (30%) cases had a cytological diagnosis of benign follicular nodule. Furthermore, no significant difference between malignant SUV and benign SUV was observed.

CONCLUSIONS

Malignancy was identified in 50% of the PET-positive incidentalomas in our series. PTC constitutes the major malignant diagnosis. No diagnostic value of SUV was observed to differentiate malignant from benign lesions. Diagn. Cytopathol. 2017;45:501-506. © 2017 Wiley Periodicals, Inc.

Application of whole-body FDG-PET for cancer screening in a cohort of hospital employees

Whole-body positron emission tomography/computed tomography with the glucose analog 2-[F]fluoro-2-deoxy-D-glucose (FDG-PET/CT) has been extensively used to screen for underlying malignancies in asymptomatic individuals. We were able to survey a cohort of hospital employees using FDG-PET/CT and to report the results herein.A total of 116 hospital employees older than 55 years old were offered whole-body FDG-PET in our hospital. Ninety-seven employees (83.6%) completed the assessment from February 2014 to August 2014 in our PET center. The final confirmation of cancer was based on pathologic examination and follow-up after more than 1 year.Among the 97 participants, 92 were asymptomatic and 5 presented with previously diagnosed cancers. Six of the 92 asymptomatic participants (6.6%) with significant nodular lesions were referred for histological or cytological evaluation of the possibility of malignancy, and 1 case was considered clinically important and required surgical resection. The cancer discovery rate was 3.3% (3/92) with positive predictive value of 50% (3/6). In the 5 participants with previously identified cancers, no recurrence or metastasis was detected.The offer of whole-body FDG-PET for cancer screening was welcomed with enthusiasm by most of the hospital employees. PET/CT combines the merits of PET and CT and can be administered to and provide benefits to a select group of hospital employees.

FDG-PET/CT Limited to the Thorax and Upper Abdomen for Staging and Management of Lung Cancer

Purpose

This study evaluates the diagnostic accuracy of [F-18]-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) of the chest/upper abdomen compared to the generally performed scan from head to upper thighs, for staging and management of (suspected) lung cancer in patients with no history of malignancy or complaints outside the thorax.

Methods

FDG-PET/CT scans of 1059 patients with suspected or recently proven lung cancer, with no history of malignancy or complaints outside the thorax, were analysed in a retrospective multi-centre trial. Suspect FDG-avid lesions in the chest and upper abdomen, the head and neck area above the shoulder line and in the abdomen and pelvis below the caudal tip of the liver were noted. The impact of lesions detected in the head and neck area and abdomen and pelvis on additional diagnostic procedures, staging and treatment decisions was evaluated.

Results

The head and neck area revealed additional suspect lesions in 7.2%, and the abdomen and pelvis in 15.8% of patients. Imaging of the head and neck area and the abdomen and pelvic area showed additional lesions in 19.5%, inducing additional diagnostic procedures in 7.8%. This resulted in discovery of additional lesions considered malignant in 10.7%, changing patient management for lung cancer in 1.2%. In (suspected) lung cancer, PET/CT limited to the chest and upper abdomen resulted in correct staging in 98.7% of patients, which led to the identical management as full field of view PET in 98.8% of patients.

Conclusion

High value of FDG-PET/CT for staging and correct patient management is already achieved with chest and upper abdomen. Findings in head and neck area and abdomen and pelvis generally induce investigations with limited or no impact on staging and treatment of NSCLC, and can be interpreted accordingly.

Efficiency of fluorodeoxyglucose positron emission tomography/computed tomography to predict prognosis in breast cancer patients received neoadjuvant chemotherapy

Neoadjuvant chemotherapy (NAC) has become a standard therapy for patients with advanced breast cancer. Pathological complete response (pCR) after NAC is an important prognostic indicator, but some patients with pCR continue to experience recurrence. So new predictive and prognostic markers in addition to pCR are needed following NAC for breast cancer. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) can evaluate metastases in the entire body simultaneously, and has several potential advantages over conventional imaging modalities. The purpose of this study was to evaluate whether FDG-PET/CT can determine NAC response and whether FDG-PET/CT can be a new prognostic marker. We imaged 83 breast cancer tumors with FDG-PET/CT, ultrasound (US), and magnetic resonance imaging (MRI) to evaluate NAC efficacy. As we previously analyzed 110 breast cancers with FDG PET/CT, we defined a threshold of >1.7 maximum standardized uptake value (SUV_max) as abnormal fluorodeoxyglucose (FDG) uptake. After NAC, 16 (19.3 %) tumors had a complete response, 54 (65.1 %) had a partial response, 11 (13.3 %) showed stable disease, and 2 (2.4 %) showed progressive disease. One of the two patients with progressive disease had bone metastasis detected by FDG-PET/CT and was not operated on. Remote metastases were evident in 2.4 % of patients after NAC as determined by FDG-PET/CT. Overall, 17 patients had pathological complete response (pCR). The sensitivity of abnormal FDG uptake after NAC for non-pCR was 20.3 % and the specificity was 94.7 %. Patients with abnormal FDG uptake after NAC experienced significantly more recurrences (P = 0.004) and more of them died (P = 0.010). Moreover, the difference in disease-free survival was more significant in the estrogen receptor (ER)-negative group. FDG-PET after NAC may be more effective for predicting prognosis than for evaluating treatment response. This tendency was particularly remarkable in ER-negative breast cancer tumors. FDG-PET/CT is useful for reevaluating surgical applicability after NAC.

A preliminary report of breast cancer screening by positron emission mammography

OBJECTIVE

Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) and PET/computed tomography (PET/CT) have had a considerable impact on the detection of various malignancies. PET and PET/CT are minimally invasive methods that can provide whole-body imaging at one time. Therefore, an FDG-PET cancer screening program has been widely used in Japan. However, the breast cancer detection rate of FDG-PET cancer screening is relatively low. Therefore, FDG-PET screening is not recommended for breast cancer screening. Positron emission mammography (PEM) is a high-resolution molecular breast imaging technology. PEM can detect small breast cancers that cannot be detected on PET or PET/CT images due to limited spatial resolution. We have performed opportunistic breast cancer screening using PEM since 2011. To the best of our knowledge, this is the first report regarding PEM breast cancer screening.

METHODS

This study enrolled 265 women. PEM images were analyzed by agreement of 2 experienced nuclear medicine physicians. The readers were given information from medical interview sheet. US findings were interpreted holistically. The number of participants, patient recall rate, further examination rate, and cancer detection rate by year were calculated.

RESULTS

The overall recall rate was 8.3%; the work-up examination rate was 77.3%, and cancer detection rate was 2.3%. The positive predictive value of PEM was 27.3%. Six cancers were found by PEM screening. Five were invasive cancers and one was ductal carcinoma in situ. Histological tumor sizes were reported in three cases: 0.7, 1.2, and 2 cm.

CONCLUSION

PEM screening appears to have potential for breast cancer screening.

Quantitative Analysis of Torso FDG-PET Scans by Using Anatomical Standardization of Normal Cases from Thorough Physical Examinations

Understanding of standardized uptake value (SUV) of 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET) depends on the background accumulations of glucose because the SUV often varies the status of patients. The purpose of this study was to develop a new method for quantitative analysis of SUV of FDG-PET scan images. The method included an anatomical standardization and a statistical comparison with normal cases by using Z-score that are often used in SPM or 3D-SSP approach for brain function analysis. Our scheme consisted of two approaches, which included the construction of a normal model and the determination of the SUV scores as Z-score index for measuring the abnormality of an FDG-PET scan image. To construct the normal torso model, all of the normal images were registered into one shape, which indicated the normal range of SUV at all voxels. The image deformation process consisted of a whole body rigid registration of shoulder to bladder region and liver registration and a non-linear registration of body surface by using the thin-plate spline technique. In order to validate usefulness of our method, we segment suspicious regions on FDG-PET images manually, and obtained the Z-scores of the regions based on the corresponding voxels that stores the mean and the standard deviations from the normal model. We collected 243 (143 males and 100 females) normal cases to construct the normal model. We also extracted 432 abnormal spots from 63 abnormal cases (73 cancer lesions) to validate the Z-scores. The Z-scores of 417 out of 432 abnormal spots were higher than 2.0, which statistically indicated the severity of the spots. In conclusions, the Z-scores obtained by our computerized scheme with anatomical standardization of torso region would be useful for visualization and detection of subtle lesions on FDG-PET scan images even when the SUV may not clearly show an abnormality.

Diagnostic accuracy of FDG-PET cancer screening in asymptomatic individuals: use of record linkage from the Osaka Cancer Registry

BACKGROUND

Whole-body cancer screening with multimodalities including [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) detects a wide range of tumors. This program has been recognized as an option for opportunistic screening, particularly in Japan. However, reports on diagnostic accuracy have been limited. We aimed to evaluate the detectability and related properties of this screening program among asymptomatic individuals in a community setting.

METHODS

The study participants were 1,762 residents of Osaka Prefecture, Japan, who underwent opportunistic cancer screening at Higashitemma Clinic for the first time between November 2004 and December 2005. FDG-PET cancer screening was performed with several imaging modalities (e.g., FDG-PET, computed tomography, magnetic resonance imaging and ultrasonography) and fecal occult blood test. Screening records were linked to the Osaka cancer registry within 1 year after the screening to determine sensitivity, specificity and positive predictive values.

RESULTS

After excluding 12 participants with cancer detected before the screening, 33 were identified by the cancer registry to have primary cancers. Of these, the present screening program found that 28 were positive (6 prostate, 5 lung, 5 colorectal, 5 thyroid, 3 liver and 4 others). Sensitivity, specificity and positive predictive values were 84.8 % (28/33, 95 % confidence interval 69.1-93.3), 86.8 % (1,491/1,718, 85.1-88.3) and 10.1 % (28/277, 6.4-12.9), respectively.

CONCLUSIONS

FDG-PET cancer screening with multimodalities reasonably and accurately detects existing asymptomatic cancer. However, the numbers of false negatives and false positives were not insignificant. Facilities that provide the screening should inform participants of relevant information, including the limitations of this program.

Detection of colorectal cancer and adenomas by FDG-PET cancer screening program: results based on a nationwide Japanese survey

PURPOSE

The aim of this study was to analyze the detection rate for CRC and adenomas for asymptomatic subjects in Japan by FDG-PET cancer screening program carried out between 2006 and 2009.

METHODS

The "FDG-PET cancer screening program" included both PET and positron emission tomography with computed tomography (PET/CT) with or without other screening tests. A total of 154,783 asymptomatic subjects underwent FDG-PET cancer screening program; we analyzed the 1,808 cases with findings from any detection method that indicated suspected CRC.

RESULTS

Among the 1,808 cases, the number of cases verified as CRC and adenoma was 394 and 679, respectively. The sensitivity and positive predictive value (PPV) of FDG-PET were 86.0 and 31.7% for CRC, and 63.6 and 63.8% for CRC and adenoma. The sensitivity and PPV of fecal occult blood test (FOBT) for CRC were lower than those of FDG-PET, but higher for adenoma. Therefore, FDG-PET and FOBT were complementary for screening for CRC, and CRC and adenoma. The majority of CRC detected by the FDG-PET imaging was UICC stage 0 or I, however, detection of smaller or less invasive cancer was limited.

CONCLUSION

The FDG-PET screening program in Japan has detected CRC at an early stage and adenomas as premalignant lesions. A combination of FDG-PET and FOBT yields the best results if the intent is to detect either CRC or adenoma. However, it is absolutely clear that an FDG-PET cancer screening program cannot detect all colon lesions.

Role of combined BI-RADS assessment using mammography and sonography for evaluation of incidental hypermetabolic lesions in the breast on 18F-FDG PET-CT

BACKGROUND

PET-CT is widely used for evaluation and follow-up of malignancy. Incidental hypermetabolic lesions are often found on PET-CT, some of which are confirmed to be malignant.

PURPOSE

To estimate the role of combined Breast Imaging-Reporting and Data System (BI-RADS) assessment using mammography and sonography for evaluation of incidental hypermetabolic lesions on 18F-FDG PET-CT and to determine an appropriate next step.

MATERIAL AND METHODS

This study included incidental hypermetabolic lesions found in the breasts of 7594 women who underwent PET-CT at three university-affiliated hospitals between January 2006 and December 2011. We reviewed the maximum standardized uptake value (SUVmax) of incidental lesions, combined BI-RADS assessment of mammography and sonography, and final results. We analyzed the negative predictive values of the probably benign (categories 1-3) group and the sensitivity of suspicious (categories 4 and 5) groups according to combined BI-RADS assessment.

RESULTS

Forty-three patients (0.6%) had 49 incidental hypermetabolic lesions in the breast. Histologic diagnosis in 17 patients confirmed nine breast cancers (27.3%). Sixteen patients underwent imaging follow-up for at least 2 years; no breast cancer was detected. Thirteen patients were lost to follow-up and were excluded. For the suspicious (n = 14) and probably benign (n = 19) groups according to combined BI-RADS assessment, both the sensitivity and negative predictive values were 100%. Using an optimal diagnostic cut-off value of 2.15, the malignancy rate was not significantly different (16.7% vs. 45.5%, respectively, in the group with SUVmax < 2.15 and the group with SUVmax ≥ 2.15; P > 0.05). The SUVmax of the confirmed malignant and assumed benign groups were not significantly different (3.1% vs. 2.2%, respectively; P > 0.05).

CONCLUSION

Both mammography and sonography should be considered the next step to evaluate incidental hypermetabolic lesions on 18F-FDG PET-CT because combined BI-RADS assessment provides an excellent negative predictive value for excluding malignancy.

A comparison of positron emission tomography and colonoscopy for the detection of advanced colorectal neoplasms in subjects undergoing a health check-up

Background & Aims

There is no agreement as to whether F-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) screening for advanced colorectal neoplasms is meaningful. This retrospective study was undertaken to determine whether FDG PET/CT may be a valuable screening tool for the detection of advanced colorectal neoplasms.

Methods

A retrospective review of the records of 1,109 FDG PET/CT scans acquired from January 2007 to December 2011 was performed. Colonoscopy and FDG PET/CT imaging were performed within two days of each other. The results of colonoscopy were taken as the gold standard, either with or without the results of the histopathological examination. An advanced neoplasm was defined as the presence of a malignant tumor, an adenoma ≥1 cm, or histological evidence of high-grade dysplasia or significant villous components.

Results

A total of 36 subjects had advanced colorectal neoplasms detected by colonoscopy (totaling 38 neoplasms). Six of the 38 neoplasms were also detected by FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of FDG PET/CT in the detection of advanced colorectal neoplasms were 15.8% (6/38), 99.1% (1063/1073), 37.5% (6/16), 97.1% (1063/1095), and 96.2% (1069/1111) respectively. The presence of lesions with an endoscopic size ≤1.5 cm (P<0.001) and low-grade dysplasia (P<0.001) were the main predictors of false-negative FDG PET/CT findings.

Conclusions

We conclude that FDG PET/CT screening of advanced colorectal neoplasms is unwarranted, especially in the presence of lesions with an endoscopic size ≤1.5 cm or low-grade dysplasia.

The current status of an FDG-PET cancer screening program in Japan, based on a 4-year (2006-2009) nationwide survey

Objective

The aim of this study was to survey the 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program conducted in Japan.

Methods

The “FDG-PET cancer screening program” included both FDG-PET and positron emission tomography with computed tomography (PET/CT) with or without other combined screening tests that were performed for cancer screening in asymptomatic subjects. A total of 155,456 subjects who underwent the FDG-PET cancer screening program during 2006–2009 were analyzed.

Results

Of the 155,456 subjects, positive findings suggesting possible cancer were noted in 16,955 (10.9 %). The number of cases with detected cancer was 1,912 (1.23 % of the total screened cases, annual range 1.14–1.30 %). Of the 1,912 cases of detected cancer, positive findings on FDG-PET were present in 1,491 cases (0.96 % of the total number of screened cases). According to the results of further examinations, the true positive rate for subjects with suggested possible cancer (positive predictive value) was 32.3 % with FDG-PET. Cancers of the colon/rectum, thyroid, lung, and breast were most frequently found (396, 353, 319, and 163 cases, respectively) with high PET sensitivity (85.9, 90.7, 86.8, 84.0 %, respectively). Prostate cancer and gastric cancer (165 and 124 cases, respectively) had low PET sensitivity (37.0 and 37.9 %, respectively). The Union for International Cancer Control (UICC) clinical stage of cancer found with the FDG-PET cancer screening program was mainly Stage I.

Conclusions

The FDG-PET screening program in Japan has detected a variety of cancers at an early stage. However, several cancers were found in repeated FDG-PET cancer screening program, indicating the limitation of a one-time FDG-PET cancer screening program. The value of the FDG-PET cancer screening program is left to the judgment of individuals with regard to its potentials and limitations.

Is further evaluation needed for incidental focal uptake in the prostate in 18-fluoro-2-deoxyglucose positron emission tomography-computed tomography images?

OBJECTIVE

The aim of this study was to investigate the frequency of secondary evaluation to detect prostate cancer that was primarily manifested as abnormal hypermetabolism detected by 18-fluoro-2-deoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT). We also evaluated the association of maximum standardized uptake values (SUVmax) on PET/CT with clinicopathologic results.

MATERIALS AND METHODS

We evaluated PET/CT reports from a total of 12,037 patients to find cases with abnormal prostate hypermetabolism. Patients with known prostate cancer or a recent prostate procedure were excluded. We analyzed the frequency of secondary evaluations such as digital rectal exams (DRE), levels of serum prostate-specific antigen (PSA), and/or biopsy to confirm prostate cancer. Biopsied patients were categorized into benign and cancer groups. Clinicopathologic characteristics were compared between the groups.

RESULTS

Among 12,037 PET/CT images, 184 (1.5%) showed abnormal hypermetabolism in the prostate. Secondary evaluation was carried out in 120 patients. Biopsy was performed in 38 patients and prostate cancer was confirmed in 23 patients. The median serum PSA level was 3.2 and 49.7 ng/mL in the benign group and cancer group, respectively. The SUVmax was higher in the cancer group (5.7 ± 5.1) than in the benign group (4.8 ± 2.7), but the difference was not statistically significant (p = 0.37). In the cancer group, a high serum PSA level (≥ 20 ng/mL) was detected in 78.3% of the patients. The Gleason score was 7 in 34.7% and 8-10 in 56.5% of prostate cancer patients.

CONCLUSIONS

Hypermetabolism in the prostate was incidentally detected in 1.5% of patients, and only 65.2% of these patients underwent further evaluation (DRE and/or serum PSA levels). Among cases of incidentally detected hypermetabolism in the prostate, patients with abnormal findings (DRE and/or PSA levels) showed high positivity by biopsy, and more than two-thirds of the positive biopsies showed significant prostate cancer. Therefore, patients with hypermetabolism in the prostate should not be ignored and should be secondarily evaluated by DRE and PSA level.

Detectability of colorectal neoplasia with fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (FDG-PET/CT)

BACKGROUND

The purpose of this study was to analyze the detectability of colorectal neoplasia with fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT).

METHODS

Data for a total of 492 patients who had undergone both PET/CT and colonoscopy were analyzed. After the findings of PET/CT and colonoscopy were determined independently, the results were compared in each of the six colonic sites examined in all patients. The efficacy of PET/CT was determined using colonoscopic examination as the gold standard.

RESULTS

In all, 270 colorectal lesions 5 mm or more in size, including 70 pathologically confirmed malignant lesions, were found in 172 patients by colonoscopy. The sensitivity and specificity of PET/CT for detecting any of the colorectal lesions were 36 and 98%, respectively. For detecting lesions 11 mm or larger, the sensitivity was increased to 85%, with the specificity remaining consistent (97%). Moreover, the sensitivity for tumors 21 mm or larger was 96% (48/50). Tumors with malignant or high-grade pathology were likely to be positive with PET/CT. A size of 10 mm or smaller [odds ratio (OR) 44.14, 95% confidence interval (95% CI) 11.44-221.67] and flat morphology (OR 7.78, 95% CI 1.79-36.25) were significant factors that were associated with false-negative cases on PET/CT.

CONCLUSION

The sensitivity of PET/CT for detecting colorectal lesions is acceptable, showing size- and pathology-dependence, suggesting, for the most part, that clinically relevant lesions are detectable with PET/CT. However, when considering PET/CT for screening purposes caution must be exercised because there are cases of false-negative results.

The efficiency of healthcare facilities providing PET cancer screening in Japan

PURPOSE

The number of positron emission tomography (PET) facilities has rapidly increased in Japan in recent years. We assume there has been a downward spiral that low reimbursement prices for PET scans by public health insurance have driven these facilities to provide cancer screening, leading to a decline in efficiency with more cancer screening. The purpose of this study was to confirm this decline and clarify the determinants of efficiency.

MATERIALS AND METHODS

Questionnaire survey data from 65 facilities that provided PET cancer screening were used. Data envelopment analysis (DEA) was used to measure the efficiency of each facility. Multivariate regression analysis was then performed with each DEA score as a dependent variable, with other potential factors that might affect efficiency as independent variables.

RESULTS

We found that from 2004 to 2006 efficiency in PET facilities declined. However, significantly greater efficiency was observed for those facilities that started cancer screening earlier, were located in an area with an aging population, and were clinics and general hospitals. Conversely, significantly lower efficiency was observed for facilities with higher market share and price for PET cancer screening.

CONCLUSION

Our findings on decreasing efficiency imply that reimbursement prices should be raised to halt the downward spiral.

Management of patients following detection of unsuspected colon lesions by PET imaging

Positron emission tomography (PET) is a well-established and integral component of multimodality imaging in oncology. However, the expanded use of PET in oncological and also non-oncological imaging (such as in assessing inflammatory conditions) has identified more lesions or tumors at unsuspected locations, such as in the large bowel during examination of patients not known to have colorectal disease. We review the clinical significance of colon lesions that were discovered incidentally by PET imaging and management strategies for gastroenterologists.

Role of fluoro-2-deoxyglucose positron emission tomography for the detection of gastrointestinal tract lesions in patients with lung cancer

BACKGROUND

  The purpose of this study was to clarify the clinical characteristics of lung cancer patients with abnormal accumulation of fluoro-2-deoxyglucose (FDG) in the gastrointestinal tract imaged by positron emission tomography (PET).

METHODS

  Of 1071 consecutive patients with primary lung cancer who underwent PET from October 2005 through to March 2010, 25 patients (2.3%) showed localized abnormal FDG accumulation in the gastrointestinal tract. We retrospectively compared the location of abnormal accumulation in the gastrointestinal tract, the maximum standardized uptake value in 1 hour, and final clinical diagnosis.

RESULTS

  Of the 25 cases, 12 (48%) were true PET-positive cases (esophageal cancer in one case, gastric cancer in one, colorectal cancer in seven, gastrointestinal stromal tumor in one, and lung cancer metastasis to the stomach and small intestine in one patient each). The 13 cases with false PET-positives were gastric polyp in one, gastritis in four, colon polyp in two, diverticulitis in one, and normal physiological accumulation in five. There was also a significant difference between malignancy and benign intestinal accumulation excluding the stomach (P = 0.002).

CONCLUSION

  PET was useful for screening the gastrointestinal tract (except the stomach) for malignancy in lung cancer patients.

Radiation exposure and risk-benefit analysis in cancer screening using FDG-PET: results of a Japanese nationwide survey

OBJECTIVE

The aim of this study was to estimate radiation exposure and evaluate the risks and benefits of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in cancer screening.

METHODS

A nationwide survey of FDG-PET cancer screening was conducted in 2006, and the results were analyzed with a common index, "extension/shortening of the average life expectancy."

RESULTS

The average estimated effective dose was 4.4 mSv (male 4.7 mSv; female 4.0 mSv) for dedicated PET and 13.5 mSv (male 14.2 mSv; female 12.8 mSv) for PET/computed tomography (CT). The risk-benefit break-even age from the viewpoint of radiation exposure was in the 40s for men and 30s for women for dedicated PET and in the 50s for men and 50s (variable injection dose) or 60s (constant injection dose) for women for PET/CT.

CONCLUSIONS

FDG-PET cancer screening is beneficial for examinees above the break-even ages. The risks and benefits should be explained to examinees because of the larger radiation used in cancer FDG-PET screening compared with other X-ray tests.

Endocrine incidentalomas--challenges imposed by incidentally discovered lesions

Endocrine glands are among the organs that most frequently harbor incidentally discovered lesions. Pituitary, thyroid, parathyroid and adrenal incidentalomas are increasingly encountered in everyday practice with variable clinical implications. The major concerns are the risks of malignancy and hormonal hypersecretion mostly in the form of subclinically functioning tumors. Pituitary incidentalomas are usually microadenomas and most of the time clinically unimportant; however, incidentally discovered larger lesions require a more careful diagnostic and therapeutic approach. Thyroid incidentalomas are extremely common; exclusion of malignancy is the main concern in this clinical setting. Although parathyroid adenomas are not uncommon, these lesions are frequently missed owing to their small size and due to clinical unawareness. Adrenal incidentalomas carry a small but finite risk of malignancy. An intriguing challenge regarding incidentally discovered adrenal lesions is that a substantial proportion is associated with hormonal alterations, mainly in the form of subtle cortisol excess. Although still largely controversial, evidence is emerging that so-called subclinical hypercortisolism may not be completely harmless. The best biochemical criterion of subtle cortisol excess remains elusive. Surgical intervention in selected cases results in some beneficial effects, but more data are required in order to routinely support surgery in this clinical setting. This Review provides a brief overview of the prevalence, clinical effect and management of endocrine incidentalomas with a focus on data regarding the diagnostic and therapeutic challenges imposed by incidentally discovered adrenal lesions.

Positron emission tomography and colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related morbidity and mortality. Molecular imaging using positron emission tomography (PET) is now an integral part of multidisciplinary cancer care. In this review, we discuss the role of PET in CRC including well established indications in the assessment of recurrent disease and emerging applications such as initial staging, monitoring therapy efficacy and using PET for radiotherapy planning. With rapid advancement in imaging technology, we also discuss the future potential of combining PET and magnetic resonance imaging and the use of novel radiotracers.

Japanese Gastric Cancer Association Task Force for Research Promotion: clinical utility of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography in gastric cancer. A systematic review of the literature

Since April 2010, the Japanese Public Health Insurance System has covered the costs incurred for performing ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) imaging for patients with advanced gastric cancer. The aim of this review was to evaluate the clinical impact of PET for patients with gastric cancer. A systematic literature search was performed in PubMed/MEDLINE using the keywords "gastric cancer" and "PET" to search for relevant articles published from January 2000 to September 2010. The clinical impact of selected articles was assessed by the authors to evaluate the following: (a) tumor staging, (b) diagnosis for recurrent disease, (c) evaluation of treatment response, and (d) screening for gastric cancer. FDG uptake increases in papillary adenocarcinoma, tubular adenocarcinoma, and solid-type poorly differentiated adenocarcinoma. This uptake is also associated with glucose transporter 1 expression. The sensitivity and specificity of FDG-PET for metastatic lymph node detection were 21-40% and 89-100%, respectively. The sensitivity and specificity for distant metastasis detection were 35-74% and 74-99%, respectively. Treatment response can be detectable at an earlier stage by PET than by computed tomography (CT), because FDG uptake by cancer cells decreases according to the treatment response. In summary, although PET has limitations such as frequent false-negative cases in signet-ring cell carcinoma and non-solid type poorly differentiated carcinoma, it can contribute to the selection of a more appropriate treatment modality by detecting distant metastases and treatment response.

Significance of incidental focal uptake in prostate on 18-fluoro-2-deoxyglucose positron emission tomography CT images

To evaluate the clinical significance of incidental focal prostate fluorodeoxyglucose (FDG) uptake, we reviewed 18-F-FDG positron emission tomography (PET)/CT scans from 2003 to 2007 and selected cases with focal FDG uptake in prostate. Cases of known prostate cancer were excluded. The maximum standardised uptake value (SUV(max)), site (central or peripheral) and pattern (discrete or ill-defined) of FDG uptake, calcification (present or absent) and prostate volume (<30 or ≥30 cc) were recorded. The PET/CT findings were correlated with serum prostate-specific antigen (PSA) levels, imaging studies, clinical follow-up and biopsy. Of a total of 5119 cases, 63 (1.2%) demonstrated focal FDG uptake in prostate. Eight cases were lost to follow-up. Among the 55 cases with follow-up, malignancy was confirmed by biopsy in 3 (5.4%). The three malignant cases had SUV(max) values of 3.3, 3.6 and 2.3, and all were noted in the peripheral portion of prostate; two of these cases had a discrete FDG uptake pattern, none had calcification corresponding to the FDG uptake area and one had a prostatic volume greater than 30 cc. The mean SUV(max) of 52 benign cases was 3.2 ± 1.7 and focal FDG uptake was noted in the peripheral portion in 34 (65%), 20 (38%) cases showed a discrete FDG uptake pattern, 35 (67%) were accompanied by calcification and 32 (62%) had a prostatic volume greater than 30 cc. The majority of cases demonstrating focal FDG uptake in prostate were benign and no PET/CT finding could reliably differentiate benign from malignant lesions; however, when discrete focal FDG uptake without coincidental calcification is seen, particularly in the peripheral zone of the prostate, further clinical evaluation is recommended.

Analysis of various malignant neoplasms detected by FDG-PET cancer screening program: based on a Japanese Nationwide Survey

OBJECTIVE

The most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan.

METHODS

"FDG-PET cancer screening" was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.

RESULTS

The detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.

CONCLUSION

We analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

Objective:

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas ≥10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off.

Methods:

84 patients, who underwent PET/CT and colonoscopy (n = 79)/sigmoidoscopy (n = 5) for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\left( {{\hbox{79}} \times {\hbox{6}} + {\hbox{5}} \times {\hbox{2}}} \right)} = {\hbox{484}}$$\end{document} colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs.

Results:

Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n = 23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n = 10) the SUV_max was ≥5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV_max.

Conclusion:

FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV_max ≥ 5 improves the accuracy.

High incidence of thyroid cancer in focal thyroid incidentaloma detected by 18F-fluorodeoxyglucose [corrected] positron emission tomography in relatively young healthy subjects: results of 3-year follow-up

As 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is becoming a common imaging modality, the number of thyroid incidentalomas identified by FDG-PET (PET incidentaloma) is increasing. The purpose of this study was to elucidate the risk of cancer in focal thyroid PET incidentaloma in healthy subjects of relatively younger age as well as the usefulness of repeated FDG-PET. The study was conducted with an observation period of three years. A total of 1,501 healthy volunteers (mean age, 43.5+/-9.7 years) underwent the first FDG-PET from August 2003 to July 2004. When focal thyroid PET incidentaloma was found, further diagnostic examination was conducted. When thyroid cancer was suspected, surgical resection was performed with the patient' s agreement. Patients with PET incidentaloma without surgery were offered annual US and FDG-PET and finally FNAB was performed in the fourth year. Focal thyroid PET incidentaloma was observed in 20 subjects. The final diagnoses in 20 subjects were malignant in 11 (ten papillary thyroid carcinoma (PTC) and one thyroid carcinoma showing thymus-like differentiation), indeterminate in one, and benign in eight subjects. Seven patients not treated surgically at the first examination had annual FDG-PET. One patient with PTC showed increasing SUVmax, but another with a benign nodule exhibited a similar increase. Others (one with PTC, one with an indeterminate nodule, and three with benign nodules) exhibited negligible SUVmax changes. When closely examined, focal thyroid PET incidentaloma in relatively young healthy adults has a high probability of malignancy. Repeated FDG-PET to follow up patients with thyroid nodules is ineffective.

Cancer screening using 18F-FDG PET/CT in Korean asymptomatic volunteers: a preliminary report

OBJECTIVE

This study was performed to evaluate the clinical value of (18)F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) for cancer screening in Korean asymptomatic people.

METHODS

Between February 2004 and December 2006, 1,587 asymptomatic individuals underwent FDG PET/CT as part of a cancer screening program with some other diagnostic tests at the healthcare center of our hospital. After excluding patients with a history of malignant tumor, 1,336 subjects were enrolled. All PET/CT images were visually analyzed. In subjects showing positive findings for PET/CT or other screening tests, further diagnostic tests and pathological confirmation were performed.

RESULTS

Of the 1,336 subjects, malignant tumors were found in 16 participants (1.2%, thyroid cancer: 9, lung cancer: 2, stomach cancer: 2, and others: 4). There were 47 cases (3.6%) of positive PET/CT findings--11 cases were true positive (thyroid cancer: 8, lung cancer: 1, renal cancer: 1, and invasive thymoma), and 36 false positive, and five cases were false negative. The overall detection rate of PET/CT was 0.8%, and the sensitivity, specificity, positive-predictive value, and negative-predictive value of PET/CT were 68.8, 97.2, 23.4, and 99.6%, respectively.

CONCLUSIONS

Fluorodeoxyglucose positron-emission tomography has the potential to detect various kinds of malignant tumors in cancer screening test, and the overall detection rate of PET/CT was 0.8%. FDG PET/CT can be a useful cancer screening modality with the selection of high-risk group and appropriate combination with other screening modalities.

Prospective evaluation of whole-body cancer screening with multiple modalities including [18F]fluorodeoxyglucose positron emission tomography in a healthy population: a preliminary report

PURPOSE

To prospectively evaluate the utility of whole-body cancer screening with multiple modalities including [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in a healthy population. This report summarizes the results of the first three annual screenings.

PARTICIPANTS AND METHODS

A total of 1,197 healthy volunteers > or = 35 years old were enrolled between August 2003 and July 2004 and offered annual cancer screening for 5 years with subsequent long-term follow-up. Screening modalities included were whole-body FDG-PET, chest and abdominal computed tomography (CT), brain and pelvic magnetic resonance imaging, several tumor markers, and fecal occult blood testing.

RESULTS

As of the end of 2006, 22 primary cancers were pathologically confirmed. Nineteen of 22 were detected by the screening; 18 in the initial, one in the second, and none in the third. Three were diagnosed after development of symptoms. Of the 18 detected in the initial screening (six thyroid, four lung, three prostate, three breast, one endometrial, and one thymic), 12 were at stage I and 11 were PET positive. PET-negative cancers were detected by CT or the prostate-specific antigen (PSA) test. Sensitivity and specificity were 50.0% (11 of 22) and 93.2% (1,095 of 1,175), respectively, for FDG-PET alone and 81.8% (18 of 22) and 82.0% (963 of 1,175), respectively, for the combination of imaging modalities and PSA.

CONCLUSION

While FDG-PET alone is insufficient, whole-body cancer screening with selected modalities including FDG-PET has initial performance supporting possible utility by detecting a wide variety of early-stage cancers with reasonable sensitivity. However, the detection of many indolent cancers and false positives necessitate continuing study for appropriate evaluation.

[Risk-benefit analysis of 18FDG PET cancer screening]

The benefits of (18)F-fluorodeoxyglucose ((18)FDG) positron emission tomography (PET) cancer screening are expected to include a large population of examinees and are intended for a healthy group. Therefore, we attempted to determine the benefit/risk ratio, estimated risk of radiation exposure, and benefit of cancer detection. We used software that embodied the method of the International Commission on Radiological Protection (ICRP) to calculate the average duration of life of radiation exposure. We calculated the lifesaving person years of benefit to be obtained by (18)FDG PET cancer screening detection. We also calculated the benefit/risk ratio using life-shortening and lifesaving person years. According to age, the benefit/risk ratio was more than 1 at 35-39 years old for males and 30-34 years old for females. (18)FDG PET cancer screening also is effective for examinees older than this. A risk-benefit analysis of (18)FDG-PET/computed tomography (CT) cancer screening will be necessary in the future.

Evaluation of whole-body cancer screening using 18F-2-deoxy-2-fluoro-D-glucose positron emission tomography: a preliminary report

OBJECTIVE

(18)F-2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) is a promising screening modality targeting whole body. However, the validity of PET cancer screening remains to be assessed. Even the screening accuracy for whole-body screening using FDG-PET has not been evaluated. In this study, we investigated the screening accuracy of PET cancer screening.

METHODS

A total of 2911 asymptomatic participants (1629 men and 1282 women, mean age 59.79 years) underwent both FDG-PET and other thorough examinations for multiple organs (gastrofiberscopy, total colonofiberscopy or barium enema, low-dose thin section computed tomography and sputum cytology, abdominal ultrasonography, an assay of prostate-specific antigen, mammography, mammary ultrasonography, Pap smear for the uterine cervix, and magnetic resonance imaging for the endometrium and ovaries) between February 2004 and January 2005, and followed sufficiently. The detection rate, sensitivity, specificity, and positive predictive value of FDG-PET were calculated using cancer data obtained from all examinations along with a 1 year follow-up.

RESULTS

From among 2911 participants FDG-PET found 28 cancers, 129 cancers were PET negative. PET-positive cancers comprised seven colorectal cancers, four lung cancers, four thyroid cancers, three breast cancers, two gastric cancers, two prostate cancers, two small intestinal sarcomas (gastrointestinal stromal tumors), one malignant lymphoma, one head and neck malignancy (nasopharyngeal carcinoid tumor), one thymoma, and one hepatocellular carcinoma. PET-negative cancers included 22 gastric cancers and 20 prostate cancers that were essentially difficult to detect using FDG-PET. The overall detection rate, sensitivity, specificity, and positive predictive value were estimated to be 0.96%, 17.83%, 95.15%, and 11.20%, respectively.

CONCLUSIONS

FDG-PET can detect a variety of cancers at an early stage as part of a whole-body screening modality. The detection rate of PET cancer screening was higher than that of other screening modalities, which had already shown evidence of efficacy. However, the sensitivity of PET cancer screening was lower than that of other thorough examinations performed at our institute. FDG-PET has some limitations, and cancer screening using only FDG-PET is likely to miss some cancers.