Reduction in respiratory motion artefacts on gadoxetate-enhanced MRI after training technicians to apply a simple and more patient-adapted breathing command.

OBJECTIVE: To investigate whether a trained group of technicians using a modified breathing command during gadoxetate-enhanced liver MRI reduces respiratory motion artefacts compared to non-trained technicians using a traditional breathing command. MATERIALS AND METHODS: The gadoxetate-enhanced liver MR images of 30 patients acquired using the traditional breathing command and the subsequent 30 patients after training the technicians to use a modified breathing command were analyzed. A subgroup of patients (n = 8) underwent scans both by trained and untrained technicians. Images obtained using the traditional and modified breathing command were compared for the presence of breathing artefacts [respiratory artefact-based image quality scores from 1 (best) to 5 (non-diagnostic)]. RESULTS: There was a highly significant improvement in the arterial phase image quality scores in patients using the modified breathing command compared to the traditional one (P < 0.001). The percentage of patients with severe and extensive breathing artefacts in the arterial phase decreased from 33.3 % to 6.7 % after introducing the modified breathing command (P = 0.021). In the subgroup that underwent MRI using both breathing commands, arterial phase image quality improved significantly (P = 0.008) using the modified breathing command. CONCLUSION: Training technicians to use a modified breathing command significantly improved arterial phase image quality of gadoxetate-enhanced liver MRI. KEY POINTS: • A modified breathing command reduced respiratory artefacts on arterial-phase gadoxetate-enhanced MRI (P < 0.001). • The modified command decreased severe and extensive arterial-phase breathing artefacts (P = 0.021). • Training technicians to use a modified breathing command improved arterial-phase images.

Tumor imaging in patients with advanced tumors using a new (99m) Tc-radiolabeled vitamin B12 derivative.

UNLABELLED: Targeting cancer cells with vitamin B12 (cobalamin) is hampered by unwanted physiologic tissue uptake mediated by transcobalamin. Adhering to good manufacturing practice, we have developed a new (99m)Tc-cobalamin derivative ((99m)Tc(CO)3-[(4-amido-butyl)-pyridin-2-yl-methyl-amino-acetato] cobalamin, (99m)Tc-PAMA-cobalamin). The derivative shows no binding to transcobalamin but is recognized by haptocorrin, a protein present in the circulation and notably expressed in many tumor cells. In this prospective study, we investigated cancer-specific uptake of (99m)Tc-PAMA-cobalamin in 10 patients with various metastatic tumors. METHODS: Ten patients with biopsy-proven metastatic cancer were included. Dynamic imaging was started immediately after injection of 300-500 MBq of (99m)Tc-PAMA-cobalamin, and whole-body scintigrams were obtained at 10, 30, 60, 120, and 240 min and after 24 h. The relative tumor activity using SPECT/CT over the tumor region after 4 h was measured in comparison to disease-free lung parenchyma. Patients 3-10 received between 20 and 1,000 µg of cobalamin intravenously before injection of (99m)Tc-PAMA-cobalamin. The study population comprised 4 patients with adenocarcinomas of the lung, 3 with squamous cell carcinomas of the hypopharyngeal region, 1 with prostate adenocarcinoma, 1 with breast, and 1 with colon adenocarcinoma. RESULTS: The median age of the study group was 61 ± 11 y. Six of 10 patients showed positive tumor uptake on (99m)Tc-PAMA-cobalamin whole-body scintigraphy. The scan was positive in 1 patient with colon adenocarcinoma, in 3 of 4 lung adenocarcinomas, in 1 of 3 hypopharyngeal squamous cell carcinomas, and in 1 breast adenocarcinoma. Renal uptake was between 1% and 3% for the left kidney. Predosing with cobalamin increased the tumor uptake and improved blood-pool clearance. The best image quality was achieved with a predose of 20-100 ug of cold cobalamin. The mean patient dose was 2.7 ± 0.9 mSv/patient. CONCLUSION: To our knowledge, we report for the first time on (99m)Tc-PAMA-cobalamin imaging in patients with metastatic cancer disease and show that tumor targeting is feasible.

Combined PET/CT-perfusion in patients with head and neck cancers.

OBJECTIVES: Computed tomography perfusion (CTP) can provide information about angiogenesis and blood-flow characteristics in tumours. [18F]Fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) is one of the major oncological imaging techniques which provides information about viability of the tumour cell and partly also about its aggressiveness. The aim of the study was to investigate the relationship between FDG and CTP data in patients with head and neck cancers. MATERIALS AND METHODS: Forty-one patients with a clinically suspected head and neck cancer were prospectively included. All patients underwent a combined PET/CT with an integrated CTP examination in the area of the head and neck tumour. CTP data (BF, BV and MTT) and PET data (SUVmax, SUVmean, TLG, PETvol) were compared between tumours and (1) healthy contralateral tissue, (2) inflammatory lesions, (3) metastatic lymph nodes, and CTP data and PET data were correlated in tumours. RESULTS: Thirty-five patients had a head and neck cancer. All CTP data were statistically different between tumours, inflammatory lesions, healthy tissue and metastatic lymph nodes; PET/CT data were in part significantly different. CTP and PET parameters were not significantly correlated. CONCLUSION: CTP and PET parameters were not significantly correlated; thus, the additional CTP values provide additional insights into tumour behaviour and their glycolytic status.

Clinical impact of 18F-choline PET/CT in patients with recurrent prostate cancer.

PURPOSE: To investigate the clinical value of (18)F-fluorocholine PET/CT (CH-PET/CT) in treatment decisions in patients with recurrent prostate cancer (rPCA). METHODS: The study was a retrospective evaluation of 156 patients with rPCA and CH-PET/CT for restaging. Questionnaires for each examination were sent to the referring physicians 14-64 months after examination. Questions included information regarding initial extent of disease, curative first-line treatment, and the treatment plan before and after CH-PET/CT. Additionally, PSA values at diagnosis, after initial treatment, before CH-PET/CT and at the end of follow-up were also obtained from the questionnaires. RESULTS: Mean follow-up was 42 months. The mean Gleason score was 6.9 at initial diagnosis. Initial treatment was: radical prostatectomy in 110 patients, radiotherapy in 39, and combined prostatectomy and radiotherapy in 7. Median PSA values before CH-PET/CT and at the end of follow-up were 3.40 ng/ml and 0.91 ng/ml. PSA levels remained stable, decreased or were below measurable levels in 108 patients. PSA levels increased in 48 patients. In 75 of the 156 patients (48%) the treatment plan was changed due to the CH-PET/CT findings. In 33 patients the therapeutic plan was changed from palliative treatment to treatment with curative intent. In 15 patients treatment was changed from curative to palliative. In 8 patients treatment was changed from curative to another strategy and in 2 patients from one palliative strategy to another. In 17 patients the treatment plan was adapted. CONCLUSION: CH-PET/CT has an important impact on the therapeutic strategy in patients with rPCA and can help to determine an appropriate treatment.

Continued pemetrexed and platin-based chemotherapy in patients with malignant pleural mesothelioma (MPM): value of 18F-FDG-PET/CT.

PURPOSE: To prospectively analyze different FDG-PET/CT-parameters (modified RECIST, SUVmax, TLG, PETvol) in patients with malignant pleural mesothelioma (MPM) under continued pemetrexed and platin based treatment. METHODS: Patients with biopsy proven MPM undergoing treatment with pemetrexed and platin based treatment were prospectively included in the study. Integrated FDG-PET/CT imaging was performed within 2 weeks before therapy and after every three consecutive cycles of combined chemotherapy. All CT-images were evaluated according to the modified RECIST (modRECIST) criteria. All FDG-PET/CT images were analyzed using SUVmax (maximum Standard Uptake Value) according to the EORTC criteria, change in Total Lesion Glycolysis (TLG) and FDG volume (PETvol). Percent change in all parameters compared to the initial, pre-therapeutic and the previous FDG-PET/CT scan. ModRECIST, EORTC guidelines, increase or decrease in TLG and PETvol was correlated with overall survival (OS) using the Log Rank Test. RESULTS: 41 patients with MPM were prospectively included in this study. The median OS of the study population is 439 days (111-1128). 41 patients had initial staging, 41 patients completed 3 cycles, 28 patients completed 6 cycles, 19 patients completed 9 cycles, 11 patients completed 12 cycles, 5 patients completed 15 cycles, 4 patients completed 18 cycles and 1 patient completed 21 cycles of chemotherapy. Chemotherapy was well tolerated up to 21 cycles. SUVmax showed a high variance over time for individual patients and change in SUVmax using EORTC guidelines did not predict OS at any time point. Ongoing morphological response in CT using modRECIST had highest correlation with OS and predicted survival up to the 15th cycle of continued permetrexed and platin based treatment. The correlations of response of the volume based PET parameters (TLG and PETvol) and OS are inferior to the morphological modRECIST parameter. CONCLUSION: Permetrexed and platin based treatment in MPM patients can be given over a prolonged time with good tolerance. Therapy response should be assessed by modRECIST in CT but not with SUVmax in FDG-PET. Long term permetrexed and platin therapy should be considered in MPM patients with good tolerance of treatment and ongoing morphological response in CT.

Influence of bowel preparation before 18F-FDG PET/CT on physiologic 18F-FDG activity in the intestine.

UNLABELLED: Our objective was to investigate the use of bowel preparation before (18)F-FDG PET/CT to reduce intestinal (18)F-FDG uptake. METHODS: Sixty-five patients with abdominal neoplasias were assigned either to a bowel-preparation group (n = 26) or to a native group (n = 39). (18)F-FDG activity was measured in the small intestine and the colon. RESULTS: In the 26 patients with bowel preparation, average maximal standardized uptake value (SUVmax) was 3.5 in the small intestine and 4.4 in the colon. In the 39 patients without bowel preparation, average SUVmax was 2.6 in the small intestine and 2.7 in the colon. (18)F-FDG activity impaired diagnosis in 6 patients (23%) in the bowel-preparation group and 11 patients (28%) in the native group (P = 0.5). SUVmax in the colon was significantly higher in the bowel-preparation group (P = 0.002), but SUVmax in the small intestine did not significantly differ between the 2 groups (P = 0.088). CONCLUSION: Bowel preparation increases (18)F-FDG activity in the large intestine and is therefore not useful before PET/CT.

Combined FDG-PET/CT in response evaluation of malignant pleural mesothelioma.

PURPOSE: Based on the complex growth pattern of MPM, conventional response evaluation in this cancer entity is challenging. Therefore, there is growing interest in therapy response evaluation with FDG-PET/CT. The aim of the study was to evaluate the value of several FDG-PET/CT-parameters in therapy response evaluation concerning prediction of survival at baseline and after three cycles of therapy. PATIENTS AND METHODS: The study was performed in accordance with the regulations of the local ethics committee. Forty-one patients with proven MPM and treated with palliative pemetrexed and platinum-based chemotherapy were included. All patients were evaluated by FDG-PET/CT at baseline and after three cycles of chemotherapy. Responders and non-responders were evaluated based on modified RECIST- and EORTC-criteria. Additional PET-parameters (SUVmean, tumor lesion glycolysis (TLG) and tumor volume (PETvol)) were evaluated. Results were evaluated using the COX regression and the Kaplan-Meier method. RESULTS: None of the baseline CT-measurements or the initial PET-parameters were predictive for survival. Based on CT, after three cycles of therapy 10 patients were categorized as responders, 30 were classified as stable disease and 1 had progressive disease. Based on PET-evaluation, 14 responders were identified, 23 patients with stable disease and 4 patients were progressive. CT-response after 3 cycles of chemotherapy was significantly related to overall survival (p=0.001). However, neither SUVmax-response (p=0.61) nor SUVmean-response (p=0.68) were related to survival. A decrease of TLG and PETvol, however, was found to be predictive (TLG: p=0.01; PETvol: p=0.002). CONCLUSION: Response evaluation based on modified RECIST by CT as well as response evaluation by TLG and PETvol in FDG-PET, but not SUVmax-measurements are predictive for survival in MPM.

Feasibility of integrated CT-liver perfusion in routine FDG-PET/CT.

OBJECTIVE: To integrate CT-perfusion into a routine, clinical contrast-enhanced (ce) PET/CT protocol for the evaluation of liver metastases and to compare functional CT and PET parameters. MATERIALS AND METHODS: Forty-six consecutive patients (mean age: 60 (34-82) years; 20 f, 26 m) with known liver lesions (colorectal metastases (n = 34), primary liver cancer (n = 4), breast cancer (n = 3), anal cancer, gastric cancer, esophageal cancer, GIST, duodenal cancer (all: n = 1) who were referred for staging or therapy follow-up by [18F]-Fluoro-2-deoxy-D-glucose-positron-emission-tomography/computed-tomography imaging (FDG-PET/CT) were included. After acquisition of a low-dose PET/CT, a split-injection (70-90 mL) ce-CT-protocol, including a 35-s CT-perfusion scan of the liver and a diagnostic ce-CT of the thorax and/or abdomen (70 s delay, iv-contrast volume: 90 mL, 4 mL/s) was performed. CT-perfusion parameters (BF, BV, MTT,) and semi-quantitative PET-parameters (SUVmax, SUVmean, TLG, PETvol) were analyzed and compared. RESULTS: CT-perfusion data could be obtained in all but one patient with shallow breathing. In all patients, diagnostic ce-PET/CT quality was adequate without the use of additional contrast media. Significant correlations (P < 0.05) were found for each of BF, BV, MTT, and SUVmax, further, BF and MTT correlated with TLG. Several other correlations were seen for other perfusion and PET-parameters. CONCLUSION: Combined CT-perfusion/PET/CT-protocol without the use of additional contrast media is feasible and can be easily integrated in clinical routine. Perfusion parameters and PET-parameters are only partly correlating and therefore have to be investigated further at fixed time points during the course of disease and therapy.

Head and neck squamous cell carcinoma (HNSCC)--detection of synchronous primaries with (18)F-FDG-PET/CT.

PURPOSE: The aim of the study was to evaluate (18)F-FDG-PET/CT for the detection of synchronous primaries at initial staging of patients with head and neck squamous cell carcinoma (HNSCC). METHODS: FDG-PET/CT images acquired between March 2001 and October 2007 in 589 consecutive patients (147 women, 442 men; mean age 61.5 years, age range 32-97 years) with proven HNSCC were reviewed for the presence of synchronous primaries. Cytology, histology and/or clinical and imaging follow-up served as reference standard. RESULTS: FDG-PET/CT showed 69 suspected synchronous primaries in 62 patients of which 56 were finally confirmed in 44 patients. Of the 56 second cancers, 46 (82%) were found in the aerodigestive tract in the following locations: lung (26, 46%), head and neck (15, 17%), oesophagus (5, 9%). Ten second cancers (18%) were located outside the aerodigestive tract (colon, five; stomach, lymphoma, breast, thymus and kidney, one each). Six patients had three synchronous primaries and three patients had four synchronous cancers. Nine synchronous cancers were not detected by PET/CT (four head and neck, two lung, two oesophageal, one gastric). False-positive PET/CT findings were mainly related to benign FDG uptake in the intestine due to benign or precancerous polyps or physiological FDG uptake in other head and neck regions. Overall the prevalence of synchronous second primaries according to the reference standard was 9.5%, of which 84% were detected with FDG-PET/CT. In 80% of the patients, therapy was changed because of the detection of a synchronous primary. CONCLUSION: FDG-PET/CT detects a considerable number of synchronous primaries (8.0% prevalence) at initial staging of patients with HNSCC. Synchronous cancers were predominantly located in the aerodigestive tract, primarily in the lung, head and neck and oesophagus. Detection of second primaries has an important impact on therapy. PET/CT should be performed before panendoscopy.

Chemotherapy response assessment in stage IV melanoma patients-comparison of 18F-FDG-PET/CT, CT, brain MRI, and tumormarker S-100B.

PURPOSE: This study aims to compare the use of 18F-FDG-PET/CT, CT, brain MRI, and tumormarker S-100B in chemotherapy response assessment of stage IV melanoma patients. METHODS: In 25 patients with stage IV melanoma, FDG-PET/CT and S-100B after 2-3 months (three cycles) of chemotherapy was compared with baseline PET/CT and baseline S-100B. Retrospectively, the response was correlated with the outcome. In patients with clinical suspicion for brain metastases, MRI or CCT was performed. RESULTS: There was agreement between FDG-PET/CT and CT regarding response to chemotherapy in all patients. There was a clear trend to a longer OS of PET/CT responders (n=10) compared with PET/CT non-responders (n=15; p=0.072) with remarkably better 1-year OS of 80% compared to 40% (p=0.048). There was a significant longer PFS of PET/CT responders compared with PET/CT non-responders (p=0.002). S-100B was normal at baseline in eight of 22 patients where it was available. Chemotherapy response assessment with S-100B failed to show correlation with OS or PFS. Eleven patients developed brain metastases during treatment, first detected by PET/CT in two and by MRI or CCT in nine of 11 patients. Appearance of brain metastases was associated with a poor survival. CONCLUSIONS: 18F-FDG-PET/CT and CT alone are equally suitable for chemotherapy response assessment in melanoma patients and clearly superior to S-100B. PET/CT responders have better early survival, but this is shortlived due to late therapy failure--often with brain recurrence. Additional brain MRI for therapy response assessment in such high-risk patients is mandatory to detect brain metastases missed by PET/CT.

Staging pathways in recurrent colorectal carcinoma: is contrast-enhanced 18F-FDG PET/CT the diagnostic tool of choice?

UNLABELLED: (18)F-FDG PET/CT has gained wide acceptance for evaluation of recurrent colorectal carcinoma. However in clinical practice, contrast-enhanced CT (ceCT) is still the first-line restaging tool. The aim of this study was to investigate the value of contrast-enhanced PET/CT (cePET/CT) as a first-line restaging tool with a special focus on the importance of the use of intravenous contrast. METHODS: Fifty-four patients (17 women, 37 men; mean age, 60.3 y), referred for restaging of colorectal carcinoma, were examined with cePET/CT. Retrospective analysis was performed by 2 experienced readers by consensus: first, ceCT alone; second, non-cePET/CT; and third, cePET/CT. The number, localization, and diagnostic certainty of lesions were evaluated. Additionally, the therapeutic impact of the findings was determined. In 29 patients, histology, clinical imaging, and clinical follow-up served as the reference standard. In 25 patients, clinical follow-up and imaging served as the reference standard. RESULTS: Overall, non-cePET/CT delivered correct additional information to the ceCT findings in 27 of 54 patients (50%). This occurred in (a) 20 of 30 patients, where ceCT was found to be inconclusive, and in (b) 7 of 24 patients with conclusive ceCT findings, where non-cePET/CT found additional lesions, leading to a therapy modification in 5 patients. Compared with non-cePET/CT, cePET/CT revealed additional information in 39 of 54 patients (72%), with therapeutic relevance in 23 patients. This large number was primarily due to correct segmental localization of liver metastases, which is crucial for surgical therapy planning. CONCLUSION: On the basis of its higher accuracy and therapeutic impact compared with ceCT, our data suggest that cePET/CT might be considered as the first-line diagnostic tool for restaging in patients with colorectal cancer.

Characterization of focal bone lesions in the axial skeleton: performance of planar bone scintigraphy compared with SPECT and SPECT fused with CT.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of planar 99mTc methylene diphosphonate bone scintigraphy compared with SPECT and SPECT fused with CT in patients with focal bone lesions of the axial skeleton. SUBJECTS AND METHODS: Thirty-seven patients with 42 focal lesions of the axial skeleton were included in this prospective study. All patients underwent planar scintigraphy, SPECT through the focal lesions, and SPECT-guided CT. SPECT and CT images then were fused digitally. The three types of images were evaluated separately from one another by two experienced reviewers working to consensus. Visibility of the lesions, diagnostic performance, and certainty in diagnosis were evaluated. Performance for specific diagnoses also was evaluated. Histologic, MRI, and clinical follow-up findings were used as the reference standard. RESULTS: Visibility of the lesions was significantly better with SPECT than with planar scintigraphy (p < 0.0001). Sensitivity and specificity for differentiation of benign and malignant bone lesions were 82% and 94% for planar scintigraphy, 91% and 94% for SPECT, and 100% and 100% for SPECT fused with CT. Differences between the three methods of differentiating benign and malignant lesions did not reach statistical significance. Certainty in diagnosis was significantly higher for SPECT fused with CT than for planar scintigraphy (p = 0.004) and SPECT (p = 0.004). A specific diagnosis was made with planar scintigraphy in 64% of cases, with SPECT in 86%, and with SPECT fused with CT in all cases. CONCLUSION: Planar scintigraphy may suffice for differentiating benign and malignant lesions of the axial skeleton, but SPECT fused with CT significantly increases certainty in diagnosis and is the best tool for making a specific diagnosis.