Integrated PET/CT in the preoperative staging of lung cancer: A prospective comparison of CT,PET and integrated PET/CT

Purpose

The purpose of this study was to evaluate the role of integrated PET/CT in the staging of lung cancer compared with CT alone or PET alone.

Materials and methods

Thirty-three patients underwent integrated PET/CT for the staging of lung cancer. The tumor, node and metastasis (TNM) stages were assessed with CT, PET and integrated PET–CT and compared with the surgical and pathological staging.

Results

CT correctly evaluated the (T) status in (64%) of the patients, PET in (59%) and PET/CT in (86%). CT correctly evaluated the (N) status in (73%) of the patients, PET in (76%), and PET/CT (88%) with accuracy, sensitivity, specificity, PPV and NPV were 73%, 78%, 71%, 50% and 94% for CT, 76%, 67%, 79%, 55% and 95% for PET and 88%, 89%, 88%, 73% and 100% for PET/CT respectively, and for (M) status were 91%, 86%, 92%, 75% and 96% for CT, 88%, 71%, 92%, 71% and 92% for PET and 97%, 100%, 96%, 88% and 100% for PET/CT respectively. Regarding the overall TNM staging CT correctly staged 24 patients. PET correctly staged 23 cases while PET/CT correctly staged 30 cases. A significant difference in the accuracy of overall tumor staging between PET/CT and CT (P = 0.0412) or PET (P = 0.0233).

Conclusion

The integrated PET/CT is superior to either CT or PET in the staging of lung cancer which has an important impact on selection of the appropriate treatment regimen.     

Usefulness of 18F-fluoride PET/CT in Breast Cancer Patients with Osteosclerotic Bone Metastases

Purpose

Bone metastasis is an important factor for the treatment and prognosis of breast cancer patients. Whole-body bone scintigraphy (WBBS) can evaluate skeletal metastases, and ¹⁸F-FDG PET/CT seems to exhibit high specificity and accuracy in detecting bone metastases. However, there is a limitation of ¹⁸F-FDG PET in assessing sclerotic bone metastases because some lesions may be undetectable. Recent studies showed that ¹⁸F-fluoride PET/CT is more sensitive than WBBS in detecting bone metastases. This study aims to evaluate the usefulness of ¹⁸F-fluoride PET/CT by comparing it with WBBS and ¹⁸F-FDG PET/CT in breast cancer patients with osteosclerotic skeletal metastases.

Materials and Methods

Nine breast cancer patients with suspected bone metastases (9 females; mean age ± SD, 55.6 ± 10.0 years) underwent ^99mTc-MDP WBBS, ¹⁸F-FDG PET/CT and ¹⁸F-fluoride PET/CT. Lesion-based analysis of five regions of the skeletons (skull, vertebral column, thoracic cage, pelvic bones and long bones of extremities) and patient-based analysis were performed.

Results

¹⁸F-fluoride PET/CT, ¹⁸F-FDG PET/CT and WBBS detected 49, 20 and 25 true metastases, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of ¹⁸F-fluoride PET/CT were 94.2 %, 46.3 %, 57.7 % and 91.2 %, respectively. Most true metastatic lesions on ¹⁸F-fluoride PET/CT had osteosclerotic change (45/49, 91.8 %), and only four lesions showed osteolytic change. Most lesions on ¹⁸F-FDG PET/CT also demonstrated osteosclerotic change (17/20, 85.0 %) with three osteolytic lesions. All true metastatic lesions detected on WBBS and ¹⁸F-FDG PET/CT were identified on ¹⁸F-fluoride PET/CT.

Conclusion

¹⁸F-fluoride PET/CT is superior to WBBS or ¹⁸F-FDG PET/CT in detecting osteosclerotic metastatic lesions. ¹⁸F-fluoride PET/CT might be useful in evaluating osteosclerotic metastases in breast cancer patients.     

Diagnostic accuracy of whole-body MRI/DWI image fusion for detection of malignant tumours: a comparison with PET/CT

Objective

To prospectively evaluate the diagnostic accuracy of whole-body T2-weighted (wbT2), whole-body diffusion-weighted imaging (wbDWI) and wbT2/wbDWI image fusion for malignant tumour detection compared with PET/CT.

Methods

Sixty-eight patients (44 men; 60?±?14?years) underwent PET/CT for staging of malignancy and were consecutively examined by 1.5-Tesla MRI including wbT2 and wbDWI. Two radiologists independently assessed wbDWI, wbT2, wbT2 + wbDWI (side-by-side) and wbT2 + wbDWI + wbT2/wbDWI image fusion for the presence of malignancy. PET/CT served as a reference standard.

Results

PET/CT revealed 374 malignant lesions in 48/64 (75%) patients. Detection rates and positive predictive value (PPV) of wbT2 and wbDWI alone were 64% and 84%, and 57% and 93%, respectively. Detection rates and PPV of wbT2 and wbDWI for side-by-side analysis without and with fused images were 72% and 89%, and 74% and 91%, respectively. The detection rate was significantly higher with side-by-side analysis and fused image analysis compared with wbT2 and wbDWI alone (p?=?.0159; p?<?.0001). There was no significant difference between fused image interpretation and side-by-side analysis.

Conclusions

WbDWI allows detection of malignant lesions with a similar detection rate to wbT2. Side-by-side analysis of wbT2 and wbDWI significantly improves the overall detection rate and fused image data provides no added value.     

The Clinical Usefulness of 18F-FDG PET/CT for the Evaluation of Lymph Node Metastasis in Periorbital Malignancies

Objective

The aim of this study was to assess the clinical role of ¹⁸F-FDG PET/CT for the evaluation of lymph node metastasis in periorbital malignancies, compared with CT alone.

Materials and Methods

We analyzed eighteen PET/CT and CT scans in 15 patients with biopsy-proven periorbital malignancies. We compared the diagnostic capabilities of PET/CT and CT with regard to nodal metastasis by level-by-level analysis and by N staging prediction. The reference standards were surgical pathology (n = 7) from dissected lymph node specimens and the results from radiological follow-up (n = 11, mean 20.5 months; range 10-52 months). Moreover, any changes in patient care as prompted by PET/CT were recorded and compared with treatment planning for CT alone.

Results

PET/CT had a sensitivity of 100%, while CT had a sensitivity of 57% (p = 0.03) for nodal metastasis by level-by-level analysis. PET/CT had a specificity of 97%, positive predictive value of 93%, negative predictive value of 100%, and diagnostic accuracy of 98%, while the CT values for these same parameters were 97%, 89%, 82%, and 84%, respectively. PET/CT correctly predicted N staging with an accuracy of 100%, while CT was only 83% accurate (p = 0.01). Regarding the impact on patient care, the extent of surgery for regional lymph nodes and the treatment decision were modified by PET/CT in 39% of patients.

Conclusion

PET/CT could provide useful information in the management of regional lymph node metastases in patients with periorbital malignancies.     

Potential impact of PET/CT on the initial staging of lymphoma

Purpose

The aim of this study was to investigate the potential impact of PET/CT on the initial staging of lymphoma with comparison to each of the PET and CT components alone.

Materials and methods

PET/CTs from 37 patients with lymphoma undergoing initial staging were studied. Review of PET, CT and PET/CT images were done and staging of each patient by each modality was assigned and compared together. Clinical follow-up, additional imaging and histology served as the standard of reference.

Results

PET/CT correctly diagnosed 83 nodal regions as positive for lymphomatous involvement versus 61 and 57 detected by PET and CT respectively. The respective sensitivities, specificities, and accuracies for the detection of nodal involvement were: PET: 88.4%, 65%, 94%, CT 89.1%, 60.1%, 96.1%, PET/CT 96.3%, 88.3%, 98.2%. PET/CT also correctly identified more extra-nodal lesions (n = 24) than CT (n = 16) and PET (n = 15). Correct staging was more accurate at PET/CT (n = 31) in comparison to PET alone (n = 23) and CT alone (n = 21).

Conclusions

PET/CT was superior to PET and CT in the initial staging of lymphoma with significant better performance compared to PET and CT to clarify nodal and extra-nodal involved sites. The application of PET/CT rather than CT or PET is likely to be more beneficial.     

Whole-body [18F]FDG PET/MRI vs. PET/CT in the assessment of bone lesions in oncological patients: initial results

Objectives

To compare [¹⁸?F]FDG PET/MRI with PET/CT for the assessment of bone lesions in oncologic patients.

Methods

This prospective study included 67 patients with solid tumours scheduled for PET/CT with [¹⁸?F]FDG who also underwent a whole-body PET/MRI scan. The datasets (PET/CT, PET/MRI) were rated by two readers regarding lesion conspicuity (four-point scale) and diagnostic confidence (five-point scale). Median scores were compared using the Wilcoxon test.

Results

Bone metastases were present in ten patients (15 %), and benign bone lesions in 15 patients (22 %). Bone metastases were predominantly localized in the pelvis (18 lesions, 38 %) and the spine (14 lesions, 29 %). Benign bone lesions were exclusively osteosclerotic and smaller than the metastases (mean size 6 mm vs. 23 mm). While PET/CT allowed identification of 45 of 48 bone metastases (94 %), PET/MRI allowed identification of all bone metastases (100 %). Conspicuity of metastases was high for both modalities with significantly better results using PET/MRI (p?<?0.05). Diagnostic confidence in lesion detection was high for both modalities without a significant difference. In benign lesions, conspicuity and diagnostic confidence were significantly higher with PET/CT (p?<?0.05).

Conclusions

[¹⁸?F]FDG PET/MRI shows high potential for the assessment of bone metastases by offering superior lesion conspicuity when compared to PET/CT. In hypersclerotic, benign bone lesions PET/CT still sets the reference.

Key Points

? PET/MRI and PET/CT are of equal value for the identification of disease-positive patients ? PET/MRI offers higher lesion conspicuity as well as diagnostic confidence ? PET/MRI is an attractive new alternative for the assessment of bone metastases     

Impact of Ga-68 DOTATOC PET/CT on the diagnosis and treatment of patients with multiple endocrine neoplasia

Purpose

To evaluate the impact of Ga-68 DOTATOC PET/CT on diagnosis and therapeutic management of patients with multiple endocrine neoplasia (MEN).

Materials and methods

We did 28 Ga-68 DOTATOC PET/CT in 21 MEN patients (10 female, 11 men; mean age 41.3?years). 109 lesions detected were classified into MEN-associated lesions [i.e., neuroendocrine tumors (NET)] and non-MEN-associated lesions for PET, CT, and PET/CT. The impact of Ga-68 DOTATOC PET/CT on diagnosis and therapeutic management of patients with MEN were assessed by the records of the interdisciplinary NET tumor board including histopathological findings, clinical and radiological follow-up.

Results

Ga-68 DOTATOC PET/CT had an impact on diagnosis and therapeutic management in 10/21 (47.6?%) MEN patients. For detecting NET lesions in MEN patients Ga-68 DOTATOC PET/CT reached a sensitivity/specificity of 91.7?%/93.5?%. There was a significant difference for the detection rate between Ga-68 DOTATOC PET/CT and CT alone (p?<?0.001) both using contrast-agent (p?=?0.002) or not (p?<?0.001) and also a significant difference between contrast-enhanced (CE-) CT and non-CE-CT alone (p?=?0.006).

Conclusions

GA-68 DOTATOC PET/CT allows a high detection rate of NET lesions in the context of MEN-1 syndrome as well as influence therapeutic management in nearly up to half of the patients. GA-68 DOTATOC PET/CT should include a CE-CT to improve MEN-associated NET lesion detection.     

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

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

Comparison of Diagnostic Sensitivity and Quantitative Indices Between 68Ga-DOTATOC PET/CT and 111In-Pentetreotide SPECT/CT in Neuroendocrine Tumors: a Preliminary Report

Purpose

In-pentetreotide has been used for neuroendocrine tumors expressing somatostatin receptors. Recently, ⁶⁸Ga-DOTATOC PET has been used with the advantage of high image quality. In this study, we compared quantitative indices between ¹¹¹In-pentetreotide SPECT/CT and ⁶⁸Ga-DOTATOC PET/CT.

Methods

Thirteen patients diagnosed with neuroendocrine tumors were prospectively recruited. Patients underwent ¹¹¹In-pentetreotide scans with SPECT/CT and ⁶⁸Ga-DOTATOC PET/CT before treatment. The number and location of lesions were analyzed on both imaging techniques to compare lesion detectability. Additionally, the maximal uptake count of each lesion and mean uptake count of the lungs were measured on both imagings, and target-to-normal lung ratios (TNR) were calculated as quantitative indices.

Results

Among 13 patients, 10 exhibited lesions with increased uptake on ¹¹¹In-pentetreotide SPECT/CT and/or ⁶⁸Ga-DOTATOC PET/CT. Scans with SPECT/CT detected 19 lesions, all of which were also detected on PET/CT. Moreover, 16 additional lesions were detected on PET/CT (6 in the liver, 9 in the pancreas and 1 in the spleen). PET/CT exhibited a significantly higher sensitivity than SPECT/CT (100 % vs. 54 %, P < 0.001). TNR was significantly higher on PET/CT than on SPECT/CT (99.9 ± 84.3 vs. 71.1 ± 114.9, P < 0.001) in spite of a significant correlation (r = 0.692, P = 0.01).

Conclusion

Ga-DOTATOC PET/CT has a higher diagnostic sensitivity than ¹¹¹In-pentetreotide scans with SPECT/CT. The TNR on PET/CT is higher than that of SPECT/CT, which also suggests the higher sensitivity of PET/CT. ¹¹¹In-pentetreotide SPECT/CT should be used carefully if it is used instead of ⁶⁸Ga-DOTATOC PET/CT.     

A proposal for combined MRI and PET/CT interpretation criteria for preoperative nodal staging in non-small-cell lung cancer

Objectives

To determine the positive reading criteria for malignant nodes when interpreting combined MRI and PET/CT images for preoperative nodal staging in non-small-cell lung cancer (NSCLC).

Methods

Forty-nine patients with biopsy-proven NSCLC underwent both PET/CT and thoracic MRI [diffusion weighted imaging (DWI)]. Each nodal station was evaluated for the presence of metastasis by applying either inclusive (positive if either one read positive) or exclusive (positive if both read positive) criteria in the combined interpretation of PET/CT and MRI. Nodal stage was confirmed pathologically. The combined diagnostic accuracy of PET/CT and MRI was determined on per-nodal station and per-patient bases and compared with that of PET/CT alone.

Results

In 49 patients, 39 (19%) of 206 nodal stations harboured malignant cells. Out of 206 nodal stations, 186 (90%) had concordant readings, while the rest (10%) had discordant readings. Inclusive criteria of combined PET/CT and MRI helped increase sensitivity for detecting nodal metastasis (69%) compared with PET/CT alone (46%; P?=?0.003), while specificity was not significantly decreased.

Conclusion

Inclusive criteria in combined MRI and PET/CT readings help improve significantly the sensitivity for detecting nodal metastasis compared with PET/CT alone and may decrease unnecessary open thoracotomy. Key Points ? Combined interpretation of MRI and PET/CT enhances the detection of nodal metastasis. ? Inclusive criteria of combined MRI/PET/CT improved the sensitivity for detecting nodal metastasis. ? Combined interpretation of MRI and PET/CT may reduce unnecessary open thoracotomies.     

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 ${\left( {{\hbox{79}} \times {\hbox{6}} + {\hbox{5}} \times {\hbox{2}}} \right)} = {\hbox{484}}$ 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.     

Performance of integrated FDG PET/contrast-enhanced CT in the diagnosis of recurrent colorectal cancer: Comparison with integrated FDG PET/non-contrast-enhanced CT and enhanced CT

Purpose  The aim of our study was to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) using ¹⁸F-fluorodeoxyglucose (FDG) with IV contrast for depiction of suspected recurrent colorectal cancer and to assess the impact of PET/contrast-enhanced CT findings on clinical management compared with PET/non-contrast-enhanced CT and CT component. Methods  One hundred seventy patients previously treated for colorectal cancer underwent PET/CT consisting of non-enhanced and contrast-enhanced CT for suspected recurrence. PET/contrast-enhanced CT, PET/non-contrast-enhanced CT and enhanced CT were interpreted by two experienced radiologists by consensus for each investigation. Lesion status was determined on the basis of histopathology, radiological imaging and clinical follow-up for longer than 6 months. Results  Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/contrast-enhanced CT were 93.2 (69/74), 95.8 (92/96) and 94.7% (161/170), respectively, whereas those of PET/non-contrast-enhanced CT were 89.2 (66/74), 94.8 (91/96) and 92.4% (157/170), respectively, and those of enhanced CT were 79.7 (59/74), 93.8 (90/96) and 87.6% (149/170), respectively. Sensitivity and accuracy differed significantly among the three modalities (Cochran’s Q test: p = 0.0004 and p = 0.0001, respectively).The findings of PET/contrast-enhanced CT resulted in a change of management for 64 of the 170 patients (38%) and had an effect on patient management in 12 patients (7%) diagnosed by enhanced CT alone and 4 patients (2%) diagnosed by PET/non-contrast-enhanced CT. Conclusion  Integrated PET/contrast-enhanced CT is an accurate modality for assessing colorectal cancer recurrence and led to changes in the subsequent appropriate therapy.     

Additional value of integrated PET/CT over PET alone in the initial staging and follow up of head and neck malignancy

Objective

Clinical application of FDG-PET in head and neck cancer includes identification of metastases, unknown primary head and neck malignancy, or second primary carcinoma, and also recurrent tumor after treatment. In this study, the additional value of PET/CT fusion images over PET images alone was evaluated in patients with initial staging and follow up of head and neck malignancy.

Methods

Forty patients with suspected primary head and neck malignancy and 129 patients with suspected relapse after treatment of head and neck malignancy were included. FDG-PET/CT study was performed after the intravenous administration of FDG (5 MBq/kg). Target of evaluation was set at primary tumor, cervical lymph node, and whole body. PET images and PET with CT fusion images were compared. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results of PET and PET/CT were compared with postoperative histopathological examination, and case by case comparison of PET and PET/CT results for each region was performed. The additional value of CT images over PET only images was assessed. Statistical differences in sensitivity and specificity were evaluated.

Results

In the comparative evaluation of 507 targets by PET alone and PET/CT, 401 targets showed agreement of the results. Of the 106 discordant targets, 103 showed a positive result on PET alone and negative result on PET/CT. These results showed a significant difference (p < 0.01). Sensitivity of PET/CT was slightly higher than that of PET without statistical significance, while specificity of PET/CT was significantly higher than that of PET alone (Initial staging: 90.5% vs. 62.2%, p < 0.01; Follow up: 97.2% vs. 74.4%, p < 0.01). In Fisher’s direct probability test, a significant difference was noted in the sensitivity (Initial staging: 91.3% vs. 87.0%, p < 0.01; Follow up: 93.9% vs. 91.4%, p < 0.01).

Conclusions

Combined PET/CT showed improved diagnostic performance than PET alone by decreasing the number of false positive findings in patients with initial staging and follow up of head and neck malignancy.     

Diagnostic value of diffusion-weighted magnetic resonance imaging (DWI) compared to FDG PET/CT for whole-body breast cancer staging

Purpose

The aim of the study was to prospectively compare the diagnostic value of whole-body diffusion-weighted imaging (DWI) and FDG PET/CT for breast cancer (BC) staging.

Methods

Twenty BC patients underwent whole-body FDG PET/CT and 1.5-T DWI. Lesions with qualitatively elevated signal intensity on DW images (b?=?800 s/mm²) were rated as suspicious for tumour and mapped to individual lesions and different compartments (overall 552 lesions). The apparent diffusion coefficient (ADC) value was determined for quantitative evaluation. Histopathology, MRI findings, bone scan findings, concordant findings between FDG PET/CT and DWI, CT follow-up scans and plausibility served as the standards of reference defining malignancy.

Results

According to the standards of reference, breasts harboured malignancy in 11, regional lymph nodes in 4, M1 lymph nodes in 3, bone in 7, lung in 2, liver in 3 and other tissues in 3 patients. On a compartment basis, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for the detection of malignancies were 94, 99, 98, 97 and 98% for FDG PET/CT and 91, 72, 76, 50 and 96% for DWI, respectively. Of the lesions seen on DWI only, 348 (82%) turned out to be false-positive compared to 23 (11%) on FDG PET/CT. The average lesion ADC was 820?±?300 with true-positive lesions having 929?±?252 vs 713?±?305 in false-positive lesions (p?<?0.0001).

Conclusion

Based on these initial data DWI seems to be a sensitive but unspecific modality for the detection of locoregional or metastatic BC disease. There was no possibility to quantitatively distinguish lesions using ADC. DWI alone may not be recommended as a whole-body staging alternative to FDG PET(/CT). Further studies are necessary addressing the question of whether full-body MRI including DWI may become an alternative to FDG PET/CT for whole-body breast cancer staging.     

Postoperative restaging: PET/CT impact on diagnosis and management

Purpose

The goal of this study was to assess the value of combined PET/CT in the restaging of suspected recurrent cancer and its impact on further management planning of the patients.

Patients and methods

Fourty-two patients with suspected recurrence due to new clinical, biochemical and radiologic findings were prospectively evaluated. PET/CT results were compared with PET and CT data. A final diagnosis of recurrence was confirmed by biopsy or by further clinical and radiologic work-up.

Results

Thirty nine out of 42 patients had recurrence and or distant metastases in 108 malignant sites. For the site-based analysis PET/CT showed 100% sensitivity, 80% specificity, 98% PPV, 100% NPV and 98% accuracy compared with 100%, 50%, 94%, 100% and 95%, respectively, for PET, and 87%, 50%, 94%, 28% and 83%, respectively, for CT. For the patient-based analysis, PET/CT showed 100% sensitivity, 75% specificity, 97% PPV, 100% NPV and 98% accuracy compared with 100%, 50%, 92%, 100% and 93%, respectively for PET and 86%, 75%, 97%, 38% and 86%, respectively for CT. PET/CT results changed the management of 90% of patients.

Conclusion

PET/CT provides accurate restaging of suspected recurrent cancer with a significant clinical impact on further management planning.     

Role of 18F-fluoride PET/CT in the assessment of multiple myeloma: initial experience

Purpose

The aim of this study was to report our early experience with ¹⁸F-fluoride PET/CT for detecting lesions and evaluate the usefulness of this modality in the assessment of multiple myeloma (MM).

Materials and methods

¹⁸F-fluoride PET/CT and ^99mTc-MDP bone scintigraphy (BS) studies from 7 myeloma patients (4 male and 3 female, mean age 55 years) diagnosed according to standard criteria were reviewed retrospectively. Two reviewers visually and quantitatively analyzed the images and recorded their findings after reaching a consensus. Diagnostic certainty regarding the presence or absence of myeloma lesions was evaluated according to the reference standard consisting of whole-body magnetic resonance imaging and whole-body X-ray.

Results

A total of 93 affected areas were definite according to the reference standard. Of these, 83 affected areas (89 %) were identified on ¹⁸F-fluoride PET/CT, whereas 54 affected areas (58 %) were found on BS. Mean SUVmax in the affected areas was 9.8 ± 3.2 (standard deviation) ranging from 5.0 to 21.2. A total of s17 lesions with bone fracture were also detected by ¹⁸F-fluoride PET/CT and 2 lesions (12 %) were negative on BS.

Conclusion

Our result showed that ¹⁸F-fluoride PET was a possible modality to detect areas of lesions in patients with MM.     

Evaluation of gross tumor size using CT, 18F-FDG PET, integrated 18F-FDG PET/CT and pathological analysis in non-small cell lung cancer

Purpose

The correlation of gross tumor sizes between combined ¹⁸F-FDG PET/CT images and macroscopic surgical samples has not yet been studied in detail. In the present study, we compared CT, ¹⁸F-FDG PET and combined ¹⁸F-FDG PET/CT for the delineation of gross tumor volume (GTV) and validated the results through examination of the macroscopic surgical specimen.

Methods

Fifty-two operable non-small cell lung cancer (NSCLC) patients had integrated ¹⁸F-FDG PET/CT scans preoperatively and pathological examination post-operation. Four separate maximal tumor sizes at X (lateral direction), Y (ventro-dorsal direction) and Z (cranio-caudal direction) axis were measured on ¹⁸F-FDG PET, CT, combined ¹⁸F-FDG PET/CT and surgical specimen, respectively. Linear regression was calculated for each of the three imaging measurements versus pathological measurement.

Results

No significant differences were observed among the tumor sizes measured by three images and pathological method. Compared with pathological measurement, CT size at X, Y, Z axis was larger, whereas combined ¹⁸F-FDG PET/CT and ¹⁸F-FDG PET size were smaller. Combined ¹⁸F-FDG PET/CT size was more similar to the pathological size than that of ¹⁸F-FDG PET or CT. Results of linear regressions showed that integrated ¹⁸F-FDG PET/CT was the most accurate modality in measuring the size of cancer.

Conclusions

¹⁸F-FDG PET/CT correlates more faithfully with pathological findings than ¹⁸F-FDG PET or CT. Integrated ¹⁸F-FDG PET/CT is an effective tool to define the target of GTV in radiotherapy.     

Detection of underlying malignancy in patients with paraneoplastic neurological syndromes: comparison of 18F-FDG PET/CT and contrast-enhanced CT

Purpose

To determine the value of combined ¹⁸F-FDG PET/CT with diagnostic contrast-enhanced CT (CECT) in detecting primary malignancies and metastases in patients with paraneoplastic neurological syndromes (PNS) and to compare this with CECT alone.

Methods

PET/CT scans from 66 patients with PNS were retrospectively evaluated. Two blinded readers initially reviewed the CECT portion of each PET/CT scan. In a second session 3 months later, the readers analysed the combined PET/CT scans. Findings on each study were assessed using a four-point-scale (1 normal/benign; 2 inconclusive, further diagnostic work-up may be necessary; 3 malignant; 4 inflammatory). Sensitivity and specificity for malignant findings were calculated for PET/CT and CECT. Interreader agreement was determined by calculating Cohen’s kappa. Pooled data from clinical follow-up (including histopathology and follow-up imaging, median follow-up 20.0 months) served as the reference gold standard.

Results

Both readers classified 12 findings in ten patients (15 %) as malignant on the PET/CT scans (two patients had two primary tumours). One such imaging finding (suspected thymic cancer) was false-positive (i.e. benign histology). The most common tumours were bronchial carcinoma (n?=?3), lymph node metastases of gynaecological tumours (n?=?3) and tonsillar carcinoma (n?=?2). Three of 12 findings (25 %) were not detected by CECT alone (cervical carcinoma, lymph node metastasis and tonsillar carcinoma). In a per-patient analysis, sensitivity and specificity for malignant findings were 100 % and 90 % for PET/CT and 78 % and 88 % for CECT. In 24 % (reader 1) and 21 % (reader 2) of the patients, the PET/CT findings were inconclusive. Of these findings, 57 % (reader 1) and 56 % (reader 2) were only diagnosed with PET (e.g. focal FDG uptake of the thyroid, gastrointestinal tract and ovaries). On follow-up, none of these findings corresponded to malignancy. Overall agreement between the two readers was excellent with a Cohen’s kappa of 0.95?±?0.04 (p?<?0.001) for PET/CT and 0.97?±?0.03 (p?<?0.001) for CECT alone.

Conclusion

In this cohort of patients with PNS, PET/CT exhibited improved detection of underlying malignancy versus CECT alone. While hybrid imaging produces a greater number of inconclusive findings, sensitivity is increased for the detection of head and neck and gynaecological malignancies as well as metastatic lymph node involvement.     

Discrimination and anatomical mapping of PET-positive lesions: comparison of CT attenuation-corrected PET images with coregistered MR and CT images in the abdomen

Purpose

PET/MR has the potential to become a powerful tool in clinical oncological imaging. The purpose of this prospective study was to evaluate the performance of a single T1-weighted (T1w) fat-suppressed unenhanced MR pulse sequence of the abdomen in comparison with unenhanced low-dose CT images to characterize PET-positive lesions.

Methods

A total of 100 oncological patients underwent sequential whole-body ¹⁸F-FDG PET with CT-based attenuation correction (AC), 40?mAs low-dose CT and two-point Dixon-based T1w 3D MRI of the abdomen in a trimodality PET/CT-MR system. PET-positive lesions were assessed by CT and MRI with regard to their anatomical location, conspicuity and additional relevant information for characterization.

Results

From among 66 patients with at least one PET-positive lesion, 147 lesions were evaluated. No significant difference between MRI and CT was found regarding anatomical lesion localization. The MR pulse sequence used performed significantly better than CT regarding conspicuity of liver lesions (p?<?0.001, Wilcoxon signed ranks test), whereas no difference was noted for extrahepatic lesions. For overall lesion characterization, MRI was considered superior to CT in 40?% of lesions, equal to CT in 49?%, and inferior to CT in 11?%.

Conclusion

Fast Dixon-based T1w MRI outperformed low-dose CT in terms of conspicuity and characterization of PET-positive liver lesions and performed similarly in extrahepatic tumour manifestations. Hence, under the assumption that the technical issue of MR AC for whole-body PET examinations is solved, in abdominal PET/MR imaging the replacement of low-dose CT by a single Dixon-based MR pulse sequence for anatomical lesion correlation appears to be valid and robust.     

18F-FDG PET, combined FDG-PET/CT and MRI for evaluation of bone marrow infiltration in staging of lymphoma: a systematic review and meta-analysis

Background and purpose

Evaluation of bone marrow infiltration is an essential step in the staging of lymphoma. The accuracy of ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET), combined ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) and magnetic resonance imaging (MRI) in diagnosing bone marrow involvement of lymphoma has never been systematically assessed, and the present systematic review was aimed at this issue.

Methods

MEDLINE, EMBASE, Cochrane library and some other databases, from January 1995 to July 2010, were searched for initial studies. All the studies published in English or Chinese relating to the diagnostic value of ¹⁸F-FDG PET, PET/CT and MRI for patients with bone marrow involvement of lymphoma were collected. We extracted data to calculate sensitivity, specificity, SROC curves and AUC and to test for heterogeneity. The statistic software called “Meta-Disc 1.4” was used for data analysis.

Result

In 32 included studies, PET/CT had the highest pooled sensitivity, 91.6% (95%CI: 85.1, 95.9) and highest pooled specificity, 90.3% (95%CI: 85.9, 93.7). PET/CT also had the highest pooled DOR, 68.89 (95%CI: 15.88, 298.92). The AUC of PET, PET/CT, and MRI were 0.9430, 0.9505 and 0.8764. There was heterogeneity among studies and no evidence of publication bias.

Conclusion

PET/CT was a highly sensitive and specific modality in diagnosing patients with bone marrow involvement in lymphoma. Compared with MRI and PET alone, PET/CT can play important roles in the staging of lymphoma.