Value of MR arthrography for evaluation of children and adolescents with clinically suspected intraarticular cause of hip pain.

PURPOSE: To evaluate the distribution of intra- and extraarticular MRI findings in children and adolescents with clinically suspected intraarticular cause of hip pain in order to assess the need for additional intraarticular contrast administration. MATERIAL AND METHODS: Database was searched over a period of 34 months retrospectively for consecutive hip MR arthrography in young patients (8-17 years) with suspected intraarticular cause of hip or groin pain. Exclusion criteria were prior hip surgery, follow-up examination due to known intraarticular pathology, incomplete examination, qualitatively non-diagnostic examinations, and missing informed consent. Reports of fellowship-trained MSK radiologists were searched for intraarticular versus extraarticular findings explaining hip or groin pain. RESULTS: Seventy patients (68% female; median age: 14.5 years; range:10.8-16.9 years) were analyzed. No reason for pain was found in 30 (42.9%) hips, extraarticular reasons in 20 (28.6%) cases, intraarticular in 14 (20.0%), and both (intra- and extraarticular) in 6 (8.6%) hips. Most common extraarticular reasons were apophysitis (14.3%), other bony stress reactions (12.9%), intramuscular edema (7%), tendinitis (5.7%), and trochanteric bursitis (4.3%). Labral pathology was the most common intraarticular finding (overall:34.3%; partial tear:15.7%, complete tear:15.7%), most frequent at the anterosuperior position (81.8%). Cartilage defects (1.4%), intraarticular neoplasia (1.4%), and tear of the femoral head ligament (2.8%) were rarely found. Synovitis and loose bodies were not observed. Cam-(37.1%) and pincer-configurations (47.1%) were common while hip dysplasia was rare (5.7%). CONCLUSION: MRI in children and adolescents with hip pain should be done primarily without intraarticular contrast administration since most cases show an extraarticular pain reason or no diagnosis detectable with MRI.

Bone SPECT/CT in Advanced Diffuse Tenosynovial Giant Cell Tumor of the Wrist.

ABSTRACT: Tenosynovial giant cell tumor, previously known as pigmented villonodular synovitis, is a benign low-grade fibrohistiocytic proliferation with hemosiderin deposits in synovial joints. Mostly affecting the knee, it can also manifest in other synovial joints, infrequently also in the wrist. Tenosynovial giant cell tumor typically causes intense radionuclide uptake in all phases in planar bone scintigraphy, making a differentiation from other bone tumors or osteomyelitis difficult, especially in cases associated with extensive bone destruction. We present a case of an unusually advanced and extended tenosynovial giant cell tumor of the wrist in bone scintigraphy, SPECT/CT, radiograph, and MRI.

Combined PET/CT-perfusion in patients with head and neck cancers might predict failure after radio-chemotherapy: a proof of concept study.

BACKGROUND: [18F]FDG-PET/CT imaging is broadly used in head and neck cancer (HNSCC) patients. CT perfusion (CTP) is known to provide information about angiogenesis and blood-flow characteristics in tumors. The aim of this study was to evaluate the potential relationship of FDG-parameters and CTP-parameters in HNSCC preand post-therapy and the potential prognostic value of a combined PET/CT with CTP. METHODS: Thirteen patients with histologic proven HNSCC were prospectively included. All patients underwent a combined PET/CT with integrated CTP before and after therapy. Pre- and post-therapeutic data of CTP and PET of the tumors were compared. Differences were tested using Spearman's rho test and Pearson's correlation. A p-value of p <0.05 was considered statistically significant. Correlations were calculated using Pearson's correlation. Bootstrap confidence intervals were calculated to test for additive confidence intervals. RESULTS: Three patients died due to malignancy recurrence, ten patients were free of recurrence until the end of the follow-up period. Patients with recurrent disease had significantly higher initial CTP-values compared to the recurrence-free patients: BFpre 267.4 (171.2)ml/100 mg/min, BVpre 40.9 (8.4)ml/100 mg and MTTpre 8.2 (6.1)sec. No higher SUVs initially but significantly higher TLG compared to patients without recurrence were found. Post-therapeutic PET-values differed significantly between the two groups: SUVmaxpost 6.0 (3.2), SUVmeanpost 3.6 (2.0) and TLG 21751.7 (29794.0). CONCLUSION: In our proof of concept study, combined PET/CT with integrated CTP might show complementary prognostic data pre- and post chemo-radiotherapy. CTP may be used to predict local tumor recurrence, while FDGPET/CT is still needed for whole-body staging.

Dosimetry and first clinical evaluation of the new 18F-radiolabeled bombesin analogue BAY 864367 in patients with prostate cancer.

UNLABELLED: The aim of this first-in-man study was to demonstrate the feasibility, safety, and tolerability, as well as provide dosimetric data and evaluate the imaging properties, of the bombesin analogue BAY 864367 for PET/CT in a small group of patients with primary and recurrent prostate cancer (PCa). METHODS: Ten patients with biopsy-proven PCa (5 with primary PCa and 5 with prostate-specific antigen recurrence after radical prostatectomy) were prospectively selected for this exploratory clinical trial with BAY 864367, a new (18)F-labeled bombesin analogue. PET scans were assessed at 6 time points, up to 110 min after intravenous administration of 302 ± 11 MBq of BAY 864367. Imaging results were compared with (18)F-fluorocholine PET/CT scans. Dosimetry was calculated using the OLINDA/EXM software. RESULTS: Three of 5 patients with primary disease showed positive tumor delineation in the prostate, and 2 of 5 patients with biochemical relapse showed a lesion suggestive of recurrence on the BAY 864367 scan. Tumor-to-background ratio averaged 12.9 ± 7.0. The ratio of malignant prostate tissue to normal prostate tissue was 4.4 ± 0.6 in 3 patients with tracer uptake in the primary PCa. Mean effective dose was 4.3 ± 0.3 mSv/patient (range, 3.7-4.9 mSv). CONCLUSION: BAY 864367, a novel (18)F-labeled bombesin tracer, was successfully investigated in a first-in-man clinical trial of PCa and showed favorable dosimetric values. Additionally, the application was safe and well tolerated. The tracer delineated tumors in a subset of patients, demonstrating the potential of gastrin-releasing-peptide receptor imaging.

First clinical results of (D)-18F-Fluoromethyltyrosine (BAY 86-9596) PET/CT in patients with non-small cell lung cancer and head and neck squamous cell carcinoma.

UNLABELLED: (D)-(18)F-fluoromethyltyrosine (d-(18)F-FMT), or BAY 86-9596, is a novel (18)F-labeled tyrosine derivative rapidly transported by the l-amino acid transporter (LAT-1), with a faster blood pool clearance than the corresponding l-isomer. The aim of this study was to demonstrate the feasibility of tumor detection in patients with non-small cell lung cancer (NSCLC) or head and neck squamous cell cancer (HNSCC) compared with inflammatory and physiologic tissues in direct comparison to (18)F-FDG. METHODS: 18 patients with biopsy-proven NSCLC (n = 10) or HNSCC (n = 8) were included in this Institutional Review Board-approved, prospective multicenter study. All patients underwent (18)F-FDG PET/CT scans within 21 d before d-(18)F-FMT PET/CT. For all patients, safety and outcome data were assessed. RESULTS: No adverse reactions were observed related to d-(18)F-FMT. Fifty-two lesions were (18)F-FDG-positive, and 42 of those were malignant (34 histologically proven and 8 with clinical reference). Thirty-two of the 42 malignant lesions were also d-(18)F-FMT-positive, and 10 lesions had no tracer uptake above the level of the blood pool. Overall there were 34 true-positive, 8 true-negative, 10 false-negative, and only 2 false-positive lesions for d-(18)F-FMT, whereas (18)F-FDG was true-positive in 42 lesions, with 10 false-positive and only 2 false-negative, resulting in a lesion-based detection rate for d-(18)F-FMT and (18)F-FDG of 77% and 95%, respectively, with an accuracy of 78% for both tracers. A high d-(18)F-FMT tumor-to-blood pool ratio had a negative correlation with overall survival (P = 0.050), whereas the (18)F-FDG tumor-to-blood pool ratio did not correlate with overall survival. CONCLUSION: d-(18)F-FMT imaging in patients with NSCLC and HNSCC is safe and feasible. The presented preliminary results suggest a lower sensitivity but higher specificity for d-(18)F-FMT over (18)F-FDG, since there is no d-(18)F-FMT uptake in inflammation. This increased specificity may be particularly beneficial in areas with endemic granulomatous disease and may improve clinical management. Further clinical investigations are needed to determine its clinical value and relevance for the prediction of survival prognosis.

Integrated ¹8F-FDG PET/perfusion CT for the monitoring of neoadjuvant chemoradiotherapy in rectal carcinoma: correlation with histopathology.

PURPOSE: The aim of this study was to prospectively monitor changes in the flow-metabolic phenotype (ΔFMP) of rectal carcinoma (RC) after neoadjuvant chemoradiotherapy (CRT) and to evaluate whether ΔFMP of RC correlate with histopathological prognostic factors including response to CRT. METHODS: Sixteen patients with RC (12 men, mean age 60.7 ± 12.8 years) underwent integrated (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/perfusion CT (PET/PCT), followed by neoadjuvant CRT and surgery. In 13 patients, PET/PCT was repeated after CRT. Perfusion [blood flow (BF), blood volume (BV), mean transit time (MTT)] and metabolic [maximum and mean standardized uptake values (SUVmax, SUVmean)] parameters as well as the FMP (BF × SUVmax) were determined before and after CRT by two independent readers and correlated to histopathological prognostic factors of RC (microvessel density, necrosis index, regression index, vascular invasion) derived from resected specimens. The diagnostic performance of ΔFMP for prediction of treatment response was determined. RESULTS: FMP significantly decreased after CRT (p < 0.001), exploiting higher changes after CRT as compared to changes of perfusion and metabolic parameters alone. Before CRT, no significant correlations were found between integrated PET/PCT and any of the histopathological parameters (all p > 0.05). After CRT, BV and SUVmax correlated positively with the necrosis index (r = 0.67/0.70), SUVmax with the invasion of blood vessels (r = 0.62) and ΔFMP with the regression index (r = 0.88; all p < 0.05). ΔFMP showed high accuracy for prediction of histopathological response to CRT (AUC 0.955, 95 % confidence interval 0.833-1.000, p < 0.01) using a cut-off value of -75%. CONCLUSION: In RC, ΔFMP derived from integrated (18)F-FDG PET/PCT is useful for monitoring the effects of neoadjuvant CRT and allows prediction of histopathological response to CRT.

Physiologic [18F]fluorodeoxyglucose uptake of floor of mouth muscles in PET/CT imaging: a problem of body position during FDG uptake?

OBJECTIVE: Assess the influence of 2 different patient positions during [18F]fluorodeoxyglucose (FDG) uptake phase on physiologic FDG accumulation of the floor of mouth (FOM) muscles. STUDY DESIGN: A prospective study design was used. METHODS: Two hundred prospectively enrolled patients were included in the study: (a) head and neck cancer (HNC) patients in supine or (b) sitting position, (c) patients with other malignant tumours in supine or (d) sitting position. An intra-individual analysis was done on patients (b) and (d) when such scans were available. Maximum standardized uptake values without correction and corrected for blood pool activity were assessed. RESULTS: The inter-individual analysis (sitting vs supine) revealed no significant differences (P = 0.17 and P = 0.56). The subgroup analysis on the patients with HNC (P = 0.56 and P = 0.15) and in patients with other malignancies (P = 0.14 and P = 0.08) revealed no significant difference; neither did the intra-individual analysis. CONCLUSIONS: The supine or sitting position during the uptake phase for FDG-positron emission tomography/computed tomography has no effect on the amount and distribution of physiologic FDG activity in the muscles of the FOM.

18F-FDG-PET/CT for the assessment of the contralateral neck in patients with head and neck squamous cell carcinoma.

OBJECTIVES/HYPOTHESIS: The aim was to compare the value of 18-Fluoro-Deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) regarding contralateral lymph node (LN) metastasis in the neck. STUDY DESIGN: Retrospective analysis of 61 patients staged by 18F-FDG-PET/CT. METHODS: Cytology/histology served as a reference standard. Further, metabolic midline invasion (MI) of the primary tumor and the presence of bilateral LN metastases were assessed. RESULTS: A true positive rate in the ipsilateral neck of 80% versus 65% in the contralateral neck was found (P = 0.067). Median-standardized uptake value (SUV)-max for suspicious LN ipsilaterally was 7.6 versus 5.8 contralaterally (P = 0.038). There was no positive correlation between metabolic MI and bilateral metastasis (P = 0.82). CONCLUSIONS: The rate of true positive detected LN by 18F-FDG-PET/CT is less on the contralateral neck side; therefore, all suspicious LNs should be verified by cytology. A high SUV in the contralateral neck suggests metastatic disease regardless of nodal size. Metabolic MI needs to be addressed carefully as it was not predictive for bilateral LN involvement. LEVEL OF EVIDENCE: 4.

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.

Correlation between therapy response assessment using FDG PET/CT and histopathologic tumor regression grade in hepatic metastasis of colorectal carcinoma after neoadjuvant therapy.

PURPOSE: To evaluate the correlation between change in FDG uptake before and after chemotherapy in hepatic metastases of colorectal carcinoma (HCRC) and a histopathologic tumor regression grade (TRG). METHODS: In patients with HCRC, PET/CT data prior to hepatic surgery were retrospectively analyzed under an IRB waiver. The maximum standard uptake value (SUVmax) was measured before and after chemotherapy. The relative change of FDG activity in the identified lesions was calculated (dSUV). Histopathological specimens of resected metastases were graded on a 5-score TRG scale. A TRG of 1-3 was rated as a responding to therapy, whereas TRG 4-5 were regarded as non-responding lesions. RESULTS: 31 lesions were identified in 23 patients. Mean SUVmax before and after therapy was 6.9 ± 3.7 and 3.5 ± 1.8, respectively. The area under the receiver operator characteristic curve revealed a conclusive correlation between TRG and dSUV (AUC 0.773; 95% confidence interval 0.599-0.946) with a cut off at 41% decrease in FDG activity yielding a sensitivity and specificity of 72 and 75%, respectively. CONCLUSION: A relative change in FDG activity (dSUV) of more than 41% decrease correlated significantly with histopathological tumor regression and might be a prognostic tool for response to chemotherapy in HCRC.

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.

Initial staging of the neck in head and neck squamous cell carcinoma: a comparison of CT, PET/CT, and ultrasound-guided fine-needle aspiration cytology.

BACKGROUND: The aim of this study was to compare imaging modalities for staging the neck in a prospective cohort of patients evaluated by CT, ultrasound with fine-needle aspiration cytology (FNAC), and [(18)F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT with the histologic evaluation of the neck dissection as the standard of reference. METHODS: In all, 76 consecutive patients were prospectively enrolled. RESULTS: Ultrasound-guided FNAC showed the highest level of agreement with histology for exact N classification. Ultrasound-guided FNAC showed the smallest percentage of overstaged patients, 7%, versus 16% with PET/CT, 13% with CT, and 13% with ultrasound. The rate of understaged patients was comparable between the imaging modalities. With regard to the endpoint N0 versus N+ there were no statistically significant differences to be found. CONCLUSIONS: Ultrasound-guided FNAC seems to correlate best with histologic staging compared with PET/CT and CT. None of the modality is reliable enough to replace elective neck treatment in cN0 necks.

Profiling gastrin-releasing peptide receptor in prostate tissues: clinical implications and molecular correlates.

BACKGROUND: The gastrin-releasing peptide receptor (GRPR) has emerged as an attractive target for both therapeutic and diagnostic appliances, but has only insufficiently been characterized in the human prostate so far. The aim of this study is to profile GRPR in a large cohort and correlate it with clinicopathologic and molecular parameters. METHODS: Benign and malignant (primary carcinoma, metastases, and castration-resistant prostate cancer) prostate samples from 530 patients were analyzed immunohistochemically for GRPR, androgen receptor and Cyclin D1 expression. Staining intensity was assessed assigning a semiquantitative score to each sample. RESULTS: Normal prostate tissues were mostly GRPR negative, significantly higher expression rates were seen in primary carcinomas and metastases. Significant inverse correlations were found for GRPR and increasing Gleason score, PSA value, and tumor size. A stratified Kaplan-Meyer analysis for GRPR and high AR expression shows a significant prognostic advantage for high GRPR expression, whereas GRPR expression alone shows no independent prognostic value. Highly significant correlations for GRPR, AR, and Cyclin D1 were found. CONCLUSIONS: Our data show that GRPR is overexpressed in prostate cancer, particularly of lower grade and smaller size. These findings constitute a caveat for the use of GRPR as a target for diagnostic or therapeutic approaches to high grade or progressed prostate cancer.

Incidence and intensity of F-18 FDG uptake after vaccination with H1N1 vaccine.

OBJECTIVE: To analyze the effect of H1N1 influenza A virus vaccination in patients referred for staging or follow-up F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for different malignant tumors. METHOD AND MATERIALS: Medical history of all patients scheduled for FDG PET/CT during the national vaccination campaign against H1N1 was evaluated for recent vaccination. Site of injection and time between PET/CT and the date of vaccination (dTime) was determined. A difference in the maximum SUV between ipsi- and contralateral deltoid muscle or axillary lymph node of more than 0.5 was determined as positive reaction. The best cut-off dTime for still visible reaction was calculated. All patients with positive ipsilateral lymph node were clinically followed. Institutional Review Board approval was waived. RESULTS: Of 269 patients, 58 (21.5%) were vaccinated for the H1N1 within 4 weeks prior to PET/CT (mean, 14.5 ± 8.7 days). Of them, 17 (29.3%) patients had FDG-positive lymph nodes (mean SUV, 1.43 ± 1.06), with a dTime range from 1 to 14 days. Only 2 of them had no increased FDG uptake in the ipsilateral deltoid muscle. The area under the receiver operator characteristic curve revealed a strong relation between time delay (dTime) and axillary activity (AUC, 0.9; 95% confidence interval, 0.816-0.983) with a cutoff at 8 days (Youden Index). At follow-up (mean, 183 days; range, 173-196 days), no patient was found to have required treatment or signs of axillary lymphadenopathy. CONCLUSIONS: H1N1 vaccination can cause false-positive FDG PET/CT findings, when administered less than 14 days before the test, with the highest probability if the vaccination was administered less than 8 days ago. Increased FDG activity in the ipsilateral deltoid muscle is a key finding for accurate interpretation of increased FDG activity in axillary lymph nodes.

FDG uptake in vaginal tampons is caused by urinary contamination and related to tampon position.

PURPOSE: The aim of the study was to determine the aetiology of FDG uptake in vaginal tampons (VT), a known artefact in premenopausal women evaluated by PET/CT. METHODS: This Institutional Review Board approved study consisted of retrospective and prospective parts. The retrospective analysis included 685 women examined between January 2008 and December 2009 regarding VT presence. PET/CT images were analysed to determine the localization and the standardized uptake value (SUV) of VTs. We prospectively recruited 24 women (20-48 years old) referred for staging or follow-up in an oncology setting between February and April 2010, who were provided a commercial VT to be used during the entire examination after obtaining written informed consent. After image acquisition, VTs were individually analysed for creatinine concentration and blood traces. Statistical significance was tested with the Mann-Whitney U test. RESULTS: In the retrospective part, 38 of 685 women were found to have a VT of which 17 (45%) were FDG positive. A statistically significant correlation was found between FDG activity and VT position below the pubococcygeal line (PCL) (13 ± 11.2 mm). In the prospective study, 7 of 24 (29%) women had increased FDG activity in their VTs (SUV 18.8 ± 11 g/ml) but were not menstruating. FDG-positive VTs were significantly lower in position (14.6 ± 11.4 mm,below the PCL) than FDG-negative VTs (p = 0.039). The creatinine concentration was significantly increased in all seven positive VTs (931 ± 615 µmol/l). CONCLUSION: FDG uptake in VTs is caused by urine contamination, which is likely related to localization below the PCL resulting in contact with urine during voiding.

Clinical value of a combined multi-phase contrast enhanced DOPA-PET/CT in neuroendocrine tumours with emphasis on the diagnostic CT component.

OBJECTIVE: To assess the clinical value of multi-phase, contrast-enhanced DOPA-PET/CT with emphasis on the diagnostic CT component in patients with neuroendocrine tumours (NET). METHODS: Sixty-five patients with NET underwent DOPA-cePET/CT. The DOPA-PET, multi-phase CT and combined DOPA cePET/CT data were evaluated and diagnostic accuracies compared. The value of ceCT in DOPA cePET/CT concerning lesion detection and therapeutic impact was evaluated. Sensitivities, specificities and accuracies were calculated. Histopathology and clinical follow-up served as the standard of reference. Differences were tested for statistical significance by McNemar's test. RESULTS: In 40 patients metastatic and/or primary tumour lesions were detected. Lesion-based analysis for the DOPA-PET showed sensitivity, specificity and accuracy of 66%, 100% and 67%, for the ceCT data 85%, 71% and 85%, and for the combined DOPA cePET/CT data 97%, 71% and 96%. DOPA cePET/CT was significantly more accurate compared with dual-phase CT (p < 0.05) and PET alone (p < 0.05). Additional lesion detection was based on ceCT in 12 patients; three patients underwent significant therapeutic changes based on the ceCT findings. CONCLUSION: DOPA cePET/CT was significantly more accurate than DOPA-PET alone and ceCT alone. The CT component itself had a diagnostic impact in a small percentage but contributed to the therapeutic strategies in selected patients.

Value of retrospective fusion of PET and MR images in detection of hepatic metastases: comparison with 18F-FDG PET/CT and Gd-EOB-DTPA-enhanced MRI.

UNLABELLED: The purpose of this study was to compare the accuracy of lesion detection and diagnostic confidence between (18)F-FDG PET/CT, gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, and retrospectively fused PET and MRI (PET/MRI). METHODS: Thirty-seven patients (mean age +/- SD, 60.2 +/- 12 y) with suspected liver metastases underwent PET/CT and Gd-EOB-DTPA-enhanced MRI within 0-30 d (mean, 11.9 +/- 9 d). PET and Gd-EOB-DTPA-enhanced MR image data were retrospectively fused. Images were reviewed independently by 2 readers who identified and characterized liver lesions using PET/CT, Gd-EOB-DTPA-enhanced MRI, and PET/MRI. Each liver lesion was graded on a 5-point confidence scale ranging from definitely benign (grade of 1) to definitely malignant (grade of 5). The accuracy of each technique was determined by receiver-operating-characteristic analysis. Histopathology served as the standard of reference for all patients with malignant lesions. RESULTS: A total of 85 liver lesions (55 liver metastases [65%] and 30 benign lesions [35%]) were present in 29 (78%) of the 37 patients. Twenty-four (65%) of the 37 patients had liver metastases. The detection rate of liver lesions was significantly lower for PET/CT than for Gd-EOB-DTPA-enhanced MRI (64% and 85%; P = 0.002). Sensitivity in the detection and characterization of liver metastases for PET/CT, Gd-EOB-DTPA-enhanced MRI, PET/MRI in reader 1, and PET/MRI in reader 2 was 76%, 91%, 93%, and 93%, respectively; the respective specificity values were 90%, 100%, 87%, and 97%. The difference in sensitivity between PET/CT and PET/MRI was significant (P = 0.023). The level of confidence regarding liver lesions larger than 1 cm in diameter was significantly higher in PET/MRI than in PET/CT (P = 0.046). Accuracy values (area under the receiver-operating-characteristic curve) for PET/CT, Gd-EOB-DTPA-enhanced MRI, PET/MRI in reader 1, and PET/MRI in reader 2 were 0.85, 0.94, 0.92, and 0.96, respectively. CONCLUSION: The sensitivity of Gd-EOB-DTPA-enhanced MRI and PET/MRI in the detection of liver metastases is higher than that of PET/CT. Diagnostic confidence was significantly better with PET/MRI than with PET/CT regarding lesions larger than 1 cm in diameter. Compared with Gd-EOB-DTPA-enhanced MRI, PET/MRI resulted in a nonsignificant increase in sensitivity and diagnostic confidence.

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.

Intraductal oncocytic papillary neoplasm of the pancreas: a radio-pathological case study.

CONTEXT: An intraductal oncocytic papillary neoplasm is a rare pancreatic tumor with the potential of developing invasive carcinoma. Its differentiation from other cystic-like neoplasms of the pancreas, such as intraductal papillary mucinous neoplasms, is a challenge for pancreatic imaging. CASE REPORT: We present the case of a 76-year-old male with painless jaundice caused by an intraductal oncocytic papillary neoplasm of the pancreas. The imaging findings on computed tomography, magnetic resonance including diffusion-weighted imaging, and (18)F-fluorodeoxyglucose positron emission tomography are presented and the radio-pathological correlations are discussed. CONCLUSION: An intraductal oncocytic papillary neoplasm of the pancreas appears as a cystic tumor communicating with the dilated pancreatic duct featuring intraductal tumor nodules. Intraductal oncocytic papillary neoplasms show a high (18)F-fluorodeoxyglucose-uptake in positron emission tomography and low diffusion values in diffusion-weighted imaging including apparent diffusion coefficient maps which may be a valuable attribute in distinguishing these rare lesions from intraductal papillary mucinous neoplasms.