Comparison of nodal staging between CT, MRI, and [18F]-FDG PET/MRI in patients with newly diagnosed breast cancer.

PURPOSE: To compare CT, MRI, and [18F]-fluorodeoxyglucose positron emission tomography ([18F]-FDG PET/MRI) for nodal status, regarding quantity and location of metastatic locoregional lymph nodes in patients with newly diagnosed breast cancer. MATERIALS AND METHODS: One hundred eighty-two patients (mean age 52.7 ± 11.9 years) were included in this prospective double-center study. Patients underwent dedicated contrast-enhanced chest/abdomen/pelvis computed tomography (CT) and whole-body ([18F]-FDG PET/) magnet resonance imaging (MRI). Thoracal datasets were evaluated separately regarding quantity, lymph node station (axillary levels I-III, supraclavicular, internal mammary chain), and lesion character (benign vs. malign). Histopathology served as reference standard for patient-based analysis. Patient-based and lesion-based analyses were compared by a McNemar test. Sensitivity, specificity, positive and negative predictive values, and accuracy were assessed for all three imaging modalities. RESULTS: On a patient-based analysis, PET/MRI correctly detected significantly more nodal positive patients than MRI (p < 0.0001) and CT (p < 0.0001). No statistically significant difference was seen between CT and MRI. PET/MRI detected 193 lesions in 75 patients (41.2%), while MRI detected 123 lesions in 56 patients (30.8%) and CT detected 104 lesions in 50 patients, respectively. Differences were statistically significant on a lesion-based analysis (PET/MRI vs. MRI, p < 0.0001; PET/MRI vs. CT, p < 0.0001; MRI vs. CT, p = 0.015). Subgroup analysis for different lymph node stations showed that PET/MRI detected significantly more lymph node metastases than MRI and CT in each location (axillary levels I-III, supraclavicular, mammary internal chain). MRI was superior to CT only in axillary level I (p = 0.0291). CONCLUSION: [18F]-FDG PET/MRI outperforms CT or MRI in detecting nodal involvement on a patient-based analysis and on a lesion-based analysis. Furthermore, PET/MRI was superior to CT or MRI in detecting lymph node metastases in all lymph node stations. Of all the tested imaging modalities, PET/MRI showed the highest sensitivity, whereas CT showed the lowest sensitivity, but was most specific.

Prospective comparison of the diagnostic accuracy of 18F-FDG PET/MRI, MRI, CT, and bone scintigraphy for the detection of bone metastases in the initial staging of primary breast cancer patients.

OBJECTIVES: To compare the diagnostic performance of [18F]FDG PET/MRI, MRI, CT, and bone scintigraphy for the detection of bone metastases in the initial staging of primary breast cancer patients. MATERIAL AND METHODS: A cohort of 154 therapy-naive patients with newly diagnosed, histopathologically proven breast cancer was enrolled in this study prospectively. All patients underwent a whole-body [18F]FDG PET/MRI, computed tomography (CT) scan, and a bone scintigraphy prior to therapy. All datasets were evaluated regarding the presence of bone metastases. McNemar χ2 test was performed to compare sensitivity and specificity between the modalities. RESULTS: Forty-one bone metastases were present in 7/154 patients (4.5%). Both [18F]FDG PET/MRI and MRI alone were able to detect all of the patients with histopathologically proven bone metastases (sensitivity 100%; specificity 100%) and did not miss any of the 41 malignant lesions (sensitivity 100%). CT detected 5/7 patients (sensitivity 71.4%; specificity 98.6%) and 23/41 lesions (sensitivity 56.1%). Bone scintigraphy detected only 2/7 patients (sensitivity 28.6%) and 15/41 lesions (sensitivity 36.6%). Furthermore, CT and scintigraphy led to false-positive findings of bone metastases in 2 patients and in 1 patient, respectively. The sensitivity of PET/MRI and MRI alone was significantly better compared with CT (p < 0.01, difference 43.9%) and bone scintigraphy (p < 0.01, difference 63.4%). CONCLUSION: [18F]FDG PET/MRI and MRI are significantly better than CT or bone scintigraphy for the detection of bone metastases in patients with newly diagnosed breast cancer. Both CT and bone scintigraphy show a substantially limited sensitivity in detection of bone metastases. KEY POINTS: • [18F]FDG PET/MRI and MRI alone are significantly superior to CT and bone scintigraphy for the detection of bone metastases in patients with newly diagnosed breast cancer. • Radiation-free whole-body MRI might serve as modality of choice in detection of bone metastases in breast cancer patients.

Incidental 18F-FDG uptake in the colon: value of contrast-enhanced CT correlation with colonoscopic findings.

OBJECTIVES: To evaluate the impact of morphological information derived from contrast-enhanced CT in the characterization of incidental focal colonic uptake in 18F-FDG PET/CT examinations. METHODS: A total of 125 patients (female: n = 53, male: n = 72) that underwent colonoscopy secondary to contrast-enhanced, full-dose PET/CT without special bowel preparation were included in this retrospective study. PET/CT examinations were assessed for focal colonic tracer uptake in comparison with the background. Focal tracer uptake was correlated with morphological changes of the colonic wall in the contrast-enhanced CT images. Colonoscopy reports were evaluated for benign, inflammatory, polypoid, precancerous, and cancerous lesions verified by histopathology, serving as a reference standard. Sensitivity, specificity, PPV, NPV, and accuracy for detection of therapeutic relevant findings were calculated for (a) sole focal tracer uptake and (b) focal tracer uptake with correlating CT findings in contrast-enhanced CT. RESULTS: In 38.4% (48/125) of the patients, a focal 18F-FDG uptake was observed within 67 lesions. Malignant lesions were endoscopically and histopathologically diagnosed in eleven patients, and nine of these were detected by focal 18F-FDG uptake. A total of 34 lesions with impact on short- or long-term patient management (either being pre- or malignant) were detected. Sensitivity, Specificity, PPV, NPV, and accuracy for sole 18F-FDG uptake for this combined group were 54%, 69%, 29%, 85%, and 65%. Corresponding results for focal 18F-FDG uptake with correlating CT findings were 38%, 90%, 50%, 86%, and 80%. This resulted in a statistically significant difference for diagnostic accuracy (p = 0.0001) CONCLUSION: By analyzing additional morphological changes in contrast-enhanced CT imaging, the specificity of focal colonic 18F-FDG uptake for precancerous and cancerous lesions can be increased but leads to a considerate loss of sensitivity. Therefore, every focal colonic uptake should be followed up by colonoscopy.

Prospective evaluation of whole-body MRI and 18F-FDG PET/MRI in N and M staging of primary breast cancer patients.

OBJECTIVES: To evaluate and compare the diagnostic potential of whole-body MRI and whole-body 18F-FDG PET/MRI for N and M staging in newly diagnosed, histopathologically proven breast cancer. MATERIAL AND METHODS: A total of 104 patients (age 53.4 ± 12.5) with newly diagnosed, histopathologically proven breast cancer were enrolled in this study prospectively. All patients underwent a whole-body 18F-FDG PET/MRI. MRI and 18F-FDG PET/MRI datasets were evaluated separately regarding lesion count, lesion localization, and lesion characterization (malignant/benign) as well as the diagnostic confidence (5-point ordinal scale, 1-5). The N and M stages were assessed according to the eighth edition of the American Joint Committee on Cancer staging manual in MRI datasets alone and in 18F-FDG PET/MRI datasets, respectively. In the majority of lesions histopathology served as the reference standard. The remaining lesions were followed-up by imaging and clinical examination. Separately for nodal-positive and nodal-negative women, a McNemar chi2 test was performed to compare sensitivity and specificity of the N and M stages between 18F-FDG PET/MRI and MRI. Differences in diagnostic confidence scores were assessed by Wilcoxon signed rank test. RESULTS: MRI determined the N stage correctly in 78 of 104 (75%) patients with a sensitivity of 62.3% (95% CI: 0.48-0.75), a specificity of 88.2% (95% CI: 0.76-0.96), a PPV (positive predictive value) of 84.6% % (95% CI: 69.5-0.94), and a NPV (negative predictive value) of 69.2% (95% CI: 0.57-0.8). Corresponding results for 18F-FDG PET/MRI were 87/104 (83.7%), 75.5% (95% CI: 0.62-0.86), 92.2% (0.81-0.98), 90% (0.78-0.97), and 78.3% (0.66-0.88), showing a significantly better sensitivity of 18F-FDG PET/MRI determining malignant lymph nodes (p = 0.008). The M stage was identified correctly in MRI and 18F-FDG PET/MRI in 100 of 104 patients (96.2%). Both modalities correctly staged all 7 patients with distant metastases, leading to false-positive findings in 4 patients in each modality (3.8%). In a lesion-based analysis, 18F-FDG PET/MRI showed a significantly better performance in correctly determining malignant lesions (85.8% vs. 67.1%, difference 18.7% (95% CI: 0.13-0.26), p < 0.0001) and offered a superior diagnostic confidence compared with MRI alone (4.1 ± 0.7 vs. 3.4 ± 0.7, p < 0.0001). CONCLUSION: 18F-FDG PET/MRI has a better diagnostic accuracy for N staging in primary breast cancer patients and provides a significantly higher diagnostic confidence in lesion characterization than MRI alone. But both modalities bear the risk to overestimate the M stage.

Prospective comparison of 18F-FDG PET/MRI and 18F-FDG PET/CT for thoracic staging of non-small cell lung cancer.

OBJECTIVES: To compare the diagnostic performance of 18F-FDG PET/MRI and 18F-FDG PET/CT for primary and locoregional lymph node staging in non-small cell lung cancer (NSCLC). METHODS: In this prospective study, a total of 84 patients (51 men, 33 women, mean age 62.5 ± 9.1 years) with histopathologically confirmed NSCLC underwent 18F-FDG PET/CT followed by 18F-FDG PET/MRI in a single injection protocol. Two readers independently assessed T and N staging in separate sessions according to the seventh edition of the American Joint Committee on Cancer staging manual for 18F-FDG PET/CT and 18F-FDG PET/MRI, respectively. Histopathology as a reference standard was available for N staging in all 84 patients and for T staging in 39 patients. Differences in staging accuracy were assessed by McNemars chi2 test. The maximum standardized uptake value (SUVmax) and longitudinal diameters of primary tumors were correlated using Pearson's coefficients. RESULTS: T stage was categorized concordantly in 18F-FDG PET/MRI and 18F-FDG PET/CT in 38 of 39 (97.4%) patients. Herein, 18F-FDG PET/CT and 18F-FDG PET/MRI correctly determined the T stage in 92.3 and 89.7% of patients, respectively. N stage was categorized concordantly in 83 of 84 patients (98.8%). 18F-FDG PET/CT correctly determined the N stage in 78 of 84 patients (92.9%), while 18F-FDG PET/MRI correctly determined the N stage in 77 of 84 patients (91.7%). Differences between 18F-FDG PET/CT and 18F-FDG PET/MRI in T and N staging accuracy were not statistically significant (p > 0.5, each). Tumor size and SUVmax measurements derived from both imaging modalities exhibited excellent correlation (r = 0.963 and r = 0.901, respectively). CONCLUSION: 18F-FDG PET/MRI and 18F-FDG PET/CT show an equivalently high diagnostic performance for T and N staging in patients suffering from NSCLC.

Prospective comparison of whole-body MRI and 68Ga-PSMA PET/CT for the detection of biochemical recurrence of prostate cancer after radical prostatectomy.

PURPOSE: To assess whole-body magnetic resonance imaging (wb-MRI) for detection of biochemical recurrence in comparison to 68Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA PET/CT) in prostate cancer (Pca) patients after radical prostatectomy. METHODS: This was a prospective trial including 28 consecutive patients (mean age 65.3 ± 9.0 years) with newly documented biochemical recurrence of Pca (mean prostate-specific antigen, PSA, 2.09 ± 1.95 ng/ml) following radical prostatectomy. All patients underwent both wb-MRI including a dedicated pelvic imaging protocol and PET/CT with 166 ± 35 MBq 68Ga-PSMA within a time window of 11 ± 10 days. PET/CT and MRI datasets were separately evaluated regarding Pca lesion count, type, localization and diagnostic confidence (three-point Likert scale, 1-3) by two nuclear medicine specialists and two radiologists, respectively. The reference standard was based on histopathological results, PSA levels following targeted salvage irradiation and follow-up imaging. Lesion-based and patient-based detection rates were compared using the chi-squared test. Differences in diagnostic confidence were assessed using the Welch test. RESULTS: A total of 56 Pca lesions were detected in 20 of the 28 patients. 68Ga-PSMA PET/CT detected 56 of 56 lesions (100%) in 20 patients (71.4%), while wb-MRI detected 13 lesions (23.2%) in 11 patients (39.3%). The higher detection rate with 68Ga-PSMA PET/CT was statistically significant on both a per-lesion basis (p < 0.001) and a per-patient basis (p = 0.0167). In 8 patients (28.6%) no relapse was detectable by either modality. All lesions detected by wb-MRI were also detected by 68Ga-PSMA PET/CT. Additionally, 68Ga-PSMA PET/CT provided superior diagnostic confidence in identifying Pca lesions (2.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.044). CONCLUSION: 68Ga-PSMA PET/CT significantly out-performed wb-MRI in the detection of biochemical recurrence in Pca patients after radical prostatectomy.

Local and whole-body staging in patients with primary breast cancer: a comparison of one-step to two-step staging utilizing 18F-FDG-PET/MRI.

OBJECTIVES: The purpose of this study was to compare the diagnostic value of a one-step to a two-step staging algorithm utilizing 18F-FDG PET/MRI in breast cancer patients. METHODS: A total of 38 patients (37 females and one male, mean age 57 ± 10 years; range 31-78 years) with newly diagnosed, histopathologically proven breast cancer were prospectively enrolled in this trial. All PET/MRI examinations were assessed for local tumor burden and metastatic spread in two separate reading sessions: (1) One-step algorithm comprising supine whole-body 18F-FDG PET/MRI, and (2) Two-step algorithm comprising a dedicated prone 18F-FDG breast PET/MRI and supine whole-body 18F-FDG PET/MRI. RESULTS: On a patient based analysis the two-step algorithm correctly identified 37 out of 38 patients with breast carcinoma (97%), while five patients were missed by the one-step 18F-FDG PET/MRI algorithm (33/38; 87% correct identification). On a lesion-based analysis 56 breast cancer lesions were detected in the two-step algorithm and 44 breast cancer lesions could be correctly identified in the one-step 18F-FDG PET/MRI (79%), resulting in statistically significant differences between the two algorithms (p = 0.0015). For axillary lymph node evaluation sensitivity, specificity and accuracy was 93%, 95 and 94%, respectively. Furthermore, distant metastases could be detected in seven patients in both algorithms. CONCLUSION: The results demonstrate the necessity and superiority of a two-step 18F-FDG PET/MRI algorithm, comprising dedicated prone breast imaging and supine whole-body imaging, when compared to the one-step algorithm for local and whole-body staging in breast cancer patients.

Heparin-bonded stent graft treatment for major visceral arterial injury after upper abdominal surgery.

PURPOSE: To analyse technical success, complications, and short- and intermediate-term outcomes after heparin-bonded stent graft implantation for the treatment of major abdominal vessel injury after upper abdominal surgery. METHODS: This retrospective, IRB-approved analysis included 29 consecutive patients (female: n = 6, male: n = 23, mean age 65.9 ± 11.2 years). All patients underwent angiography and attempted heparin-bonded stent-graft implantation because of a major visceral arterial injury after upper abdominal surgery. Electronic clinical records, angiographic reports and imaging datasets were reviewed to assess technical success and complications. Telephone interviews were performed to obtain follow-up information and to estimate short- (> 30 days) and intermediate-term (> 90 days) outcomes. RESULTS: Successful stent graft placement was achieved in 82.8% (24/29). Peri-interventional complications were observed in 20.7% (6/29) and delayed, angiography-associated complications were observed in 34.5% (10/29) of the patients. Symptomatic re-bleeding occurred in 24.1% (7/29). Short-term survival (> 30 days) was 72.4% (21/29). Intermediate survival (> 90 days) was 37.9% (11/29). CONCLUSION: Treatment of major vascular injuries with heparin-bonded stent grafts is feasible with a high technical success rate. However, survival depends on the underlying surgical condition, making interdisciplinary patient management mandatory. KEY POINTS: • Stent graft implantation is challenging, but has a high technical success rate. • Complications are frequent but surgical conversion is rarely necessary. • Survival depends on the underlying surgical condition causing the vascular injury. • Interdisciplinary management is crucial for the survival of these patients.

Imaging children suffering from lymphoma: an evaluation of different 18F-FDG PET/MRI protocols compared to whole-body DW-MRI.

OBJECTIVES: The objectives of this study were to evaluate and compare the diagnostic potential of different PET/MRI reading protocols, entailing non-enhanced / contrast-enhanced and diffusion-weighted 18F-FDG PET/MR imaging and whole-body diffusion-weighted MRI for lesion detection and determination of the tumor stage in pediatric lymphoma patients. METHODS: A total of 28 18F-FDG PET/MRI datasets were included for analysis of four different reading protocols: (1) PET/MRI utilizing sole unenhanced T2w and T1w imaging, (2) PET/MRI utilizing additional contrast enhanced sequences, (3) PET/MR imaging utilizing unenhanced, contrast enhanced and DW imaging or (4) WB-DW-MRI. Statistical analyses were performed on a per-patient and a per-lesion basis. Follow-up and prior examinations as well as histopathology served as reference standards. RESULTS: PET/MRI correctly identified all 17 examinations with active lymphoma disease, while WB-DW-MRI correctly identified 15/17 examinations. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 96%, 96.5%, 97%, 95%, and 96% for PET/MRI1; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI2; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI3 and 77%, 96%, 96%, 78.5% and 86% for MRI-DWI. CONCLUSION: 18F-FDG PET/MRI is superior to WB-DW-MRI in staging pediatric lymphoma patients. Neither application of contrast media nor DWI leads to a noticeable improvement of the diagnostic accuracy of PET/MRI. Thus, unenhanced PET/MRI may play a crucial role for the diagnostic work-up of pediatric lymphoma patients in the future.

Diagnostic potential of PET/CT using a 68Ga-labelled prostate-specific membrane antigen ligand in whole-body staging of renal cell carcinoma: initial experience.

PURPOSE: To evaluate the diagnostic potential of whole-body PET/CT using a 68Ga-labelled PSMA ligand in renal cell carcinoma (RCC). METHODS: Six patients with histopathologically proven RCC underwent 68Ga-PSMA PET/CT. Each PET/CT scan was evaluated in relation to lesion count, location and dignity. SUVmax was measured in primary tumours and PET-positive metastases. Tumour-to-background SUVmax ratios (TBRSUVmax) were calculated for primary RCCs in relation to the surrounding normal renal parenchyma. Metastasis-to-background SUVmax ratios (MBRSUVmax) were calculated for PET-positive metastases in relation to gluteal muscle. RESULTS: Five primary RCCs and 16 metastases were evaluated. The mean SUVmax of the primary RCCs was 9.9 ± 9.2 (range 1.7 - 27.2). Due to high uptake in the surrounding renal parenchyma, the mean TBRSUVmax of the primary RCCs was only 0.2 ± 0.3 (range 0.02 - 0.7). Eight metastases showed focal 68Ga-PSMA uptake (SUVmax 9.9 ± 8.3, range 3.4 - 25.6). The mean MBRSUVmax of these PET-positive metastases was 11.7 ± 0.2 (range 4.4 - 28.1). All PET-negative metastases were subcentimetre lung metastases. CONCLUSION: 68Ga-PSMA PET/CT appears to be a promising method for detecting RCC metastases. However, no additional diagnostic value in assessing the primary tumour was found.

Thoracic staging with 18F-FDG PET/MR in non-small cell lung cancer - does it change therapeutic decisions in comparison to 18F-FDG PET/CT?

OBJECTIVE: To investigate whether differences in thoracic tumour staging between 18F-FDG PET/CT and PET/MR imaging lead to different therapeutic decisions in Non-Small Cell Lung Cancer (NSCLC). MATERIAL AND METHODS: Seventy-seven NSCLC patients that underwent whole-body 18F-FDG PET/CT from the base of skull to the upper thighs and thoracic PET/MR were enrolled in this retrospective study. Thoracic PET/CT and PET/MR images were staged according to the 7th edition of the AJCC staging manual. Staging results of both modalities were discussed separately in a simulated interdisciplinary tumour board and therapeutic decisions based on both imaging modalities were recorded. Descriptive statistics were used to compare the results and reasons for changes in the therapeutic decision were investigated. RESULTS: Staging results differed in 35 % of patients (27 patients) between thoracic PET/CT and PET/MR. Differences were detected when assessing the T-stage in 18 % (n = 14), the N-stage in 23 % (n = 18), and the M-stage in 1 % (n = 1). However, patient therapy management was changed in only six patients (8 %). CONCLUSION: Despite the variability of thoracic 18F-FDG PET/CT and PET/MR in TNM-staging, both modalities lead to comparable therapeutic decisions in patients suffering from NSCLC. Hence, 18F-FDG PET/MR can be considered an possible alternative to 18F-FDG PET/CT for clinical NSCLC staging. KEY POINTS: • PET/CT and PET/MR provide comparable results in early stages in NSCLC • Clinical impact of different staging results has not been investigated • PET/CT and PET/MR lead to comparable therapeutic decisions • PET/MR can be considered an alternative to PET/CT for NSCLC staging.

Silent progression in patients with rheumatoid arthritis: is DAS28 remission an insufficient goal in RA? Results from the German Remission-plus cohort.

BACKGROUND: Remission is arguably the ultimate therapeutic goal in rheumatoid arthritis (RA). Applying modern strategies, clinical remission can be achieved in a substantial number of patients with early RA (ERA). Even in those patients, the number and scope of erosions can increase. We, therefore, investigated the value of MRI for the detection of radiological progression in patients with DAS28 improvement and/or clinical remission of the German Remission-plus cohort. METHODS: Data-sets of 80 RA patients (according to 2010 ACR/EULAR criteria) from the Remission-plus study cohort, who fulfilled the following criteria, were retrospectively analysed: availability of two consecutive MRI scans (low-field MRI, follow-up interval 1 year) of the clinically dominant hand and wrist, and the presence of DAS28 (CRP) scores at both time points, which was used to assess disease activity. RESULTS: Seventy-one of the 80 investigated patients presented a numerical improvement of the DAS28 (CRP) after 12 months (DAS28(CRP) T0 average (Ø) 4.96, SD 1.2; DAS28 T4 (12 month) Ø 2.6, SD 1.0), 73% of them also improved in the RAMRIS-Score, while 24% demonstrated an increase despite DAS28 improvement and 3% showed equal values. 48% of patients who improved in the DAS28 reached EULAR remission. 41% of these patients had an increase in the RAMRIS Erosion-subscore after 12 months. When considering EULAR response criteria (non-response (n = 7), moderate response (n = 19), good response (n = 45)), an increase of erosions was found in 71.4% of non-responders, 52.6% of moderate responders, and 31.1% of good responders after 12 months, all compared to baseline. CONCLUSION: Up to 40% of patients in this study demonstrated a progressive erosive disease detected by MRI despite DAS28 improvement or EULAR remission. Future studies are needed to determine the prognostic clinical impact of disease progression in MRI despite clinical remission, and to investigate if DAS28 remission may be an insufficient therapeutic goal and should be accompanied by MRI remission criteria.

Locoregional tumour evaluation of squamous cell carcinoma in the head and neck area: a comparison between MRI, PET/CT and integrated PET/MRI.

PURPOSE: To evaluate the accuracy of integrated (18)F-FDG PET/MR imaging for locoregional tumour evaluation compared to (18)F-FDG PET/CT and MR imaging in initial tumour and recurrence diagnosis in histopathologically confirmed head and neck squamous cell carcinoma (HNSCC). METHODS: (18)F-FDG PET/CT and integrated (18)F-FDG PET/MR imaging were performed for initial tumour staging or recurrence diagnosis in 25 patients with HNSCC. MR, fused (18)F-FDG PET/CT and fused (18)F-FDG PET/MR images were analysed by two independent readers in separate sessions in random order. In initial tumour staging, T and N staging was performed while individual lesions were analysed in patients with suspected cancer recurrence. In T and N staging, histopathological results after tumour resection served as the reference standard while histopathological sampling as well as cross-sectional and clinical follow-up were accepted in cancer recurrence diagnosis. The diagnostic accuracy of each modality was calculated separately for T and N staging as well as for tumour recurrence, and compared using McNemar's test. Values of p <0.017 were considered statistically significant after Bonferroni correction. RESULTS: In 12 patients undergoing (18)F-FDG PET/CT and (18)F-FDG PET/MR for initial tumour staging, T staging was accurate in 50 % with MRI, in 59 % with PET/CT and in 75 % with PET/MR while N staging was accurate in 75 % with MRI, in 77 % with PET/CT and in 71 % with PET/MR in relation to the reference standard. No significant differences were observed in T and N staging among the three modalities (p > 0.017). In 13 patients undergoing hybrid imaging for cancer recurrence diagnosis, diagnostic accuracy was 57 % with MRI and in 72 % with (18)F-FDG PET/CT and (18)F-FDG PET/MR, respectively. Again, no significant differences were found among the three modalities (p > 0.017). CONCLUSION: In this initial study, no significant differences were found among (18)F-FDG PET/MR, (18)F-FDG PET/CT and MRI in local tumour staging and cancer recurrence diagnosis.

Potential influence of Gadolinium contrast on image segmentation in MR-based attenuation correction with Dixon sequences in whole-body 18F-FDG PET/MR.

OBJECTIVE: To evaluate the influence of Gadolinium contrast agent on image segmentation in magnetic resonance (MR)-based attenuation correction (AC) with four-segment dual-echo time Dixon-sequences in whole-body [18F]-fluorodeoxyglucose positron emission tomography (PET)/MR imaging, and to analyze the consecutive effect on standardized uptake value (SUV). MATERIALS AND METHODS: Hybrid imaging with an integrated PET/MR system was performed in 30 oncological patients. AC was based on MR imaging with a Dixon sequence with subsequent automated image segmentation. AC maps (µmaps) were acquired and reconstructed prior to (µmap-gd) and after (µmap+gd) Gd-contrast agent application. For quantification purposes, the SUV of organs and tumors based on both µmaps were compared. RESULTS: Tissue classification based on µmap-gd was correct in 29/30 patients; based on µmap+gd, the brain was falsely classified as fat in 12/30 patients with significant underestimation of SUV. In all cancerous lesions, tissue segmentation was correct. All concordant µmaps-gd/+gd resulted in no significant difference in SUV. CONCLUSION: In PET/MR, Gd-contrast agent potentially influences fat/water separation in Dixon-sequences of the head with above-average false tissue segmentation and an associated underestimation of SUV. Thus, MR-based AC should be acquired prior to Gd-contrast agent application. Additionally, integrating the MR-based AC maps into the reading-routine in PET/MR is recommended to avoid interpretation errors in cases where tissue segmentation fails.

Diagnostic accuracy of whole-body PET/MRI and whole-body PET/CT for TNM staging in oncology.

PURPOSE: In various tumours PET/CT with [(18)F]FDG is widely accepted as the diagnostic standard of care. The purpose of this study was to compare a dedicated [(18)F]FDG PET/MRI protocol with [(18)F]FDG PET/CT for TNM staging in a cohort of oncological patients. METHODS: A dedicated [(18)F]FDG PET/MRI protocol was performed in 73 consecutive patients (mean age of 59 years, range 21 - 85 years) with different histologically confirmed solid primary malignant tumours after a routine clinical FDG PET/CT scan (60 min after injection of 295 ± 45 MBq [(18)F]FDG). TNM staging according to the 7th edition of the AJCC Cancer Staging Manual was performed by two readers in separate sessions for PET/CT and PET/MRI images. Assessment of the primary tumour and nodal and distant metastases with FDG PET/CT and FDG PET/MRI was based on qualitative and quantitative analyses. Histopathology, and radiological and clinical follow-up served as the standards of reference. A McNemar test was performed to evaluate the differences in diagnostic performance between the imaging procedures. RESULTS: From FDG PET/CT and FDG PET/MRI T stage was correctly determined in 22 (82 %) and 20 (74 %) of 27 patients, N stage in 55 (82 %) and 56 (84 %) of 67 patients, and M stage in 32 (76 %) and 35 (83 %) of 42 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for lymph node metastases were 65 %, 94 %, 79 %, 89 % and 87 % for PET/CT, and 63 %, 94 %, 80 %, 87 % and 85 % for PET/MRI. The respective values for the detection of distant metastases were 50 %, 82 %, 40 %, 88 % and 76 % for PET/CT, and 50 %, 91 %, 57 %, 89 % and 83 % for PET/MRI. Differences between the two imaging modalities were not statistically significant (P > 0.05). CONCLUSION: According to our results, FDG PET/CT and FDG PET/MRI are of equal diagnostic accuracy for TNM staging in patients with solid tumours.

Thoracic staging of non-small-cell lung cancer using integrated (18)F-FDG PET/MR imaging: diagnostic value of different MR sequences.

PURPOSE: To compare the accuracy of different MR sequences in simultaneous PET/MR imaging for T staging in non-small-cell lung cancer in relation to histopathology. METHODS: The study included 28 patients who underwent dedicated thoracic PET/MR imaging before tumour resection. Local tumour staging was performed separately by three readers with each of the following MR sequences together with PET: transverse T2 BLADE, transverse non-enhanced and contrast-enhanced T1 FLASH, T1 3D Dixon VIBE in transverse and coronal orientation, coronal T2 HASTE, and coronal TrueFISP. The staging results were compared with histopathology after resection as the reference standard. Differences in the accuracy of T staging among the MR sequences were evaluated using McNemar's test. Due to multiple testing, Bonferroni correction was applied to prevent accumulation of α errors; p < 0.0024 was considered statistically significant. RESULTS: Compared with histopathology, T-staging accuracy was 69% with T2 BLADE, 68% with T2 HASTE, 59% with contrast-enhanced T1 FLASH, 57% with TrueFISP, 50 % with non-enhanced T1 FLASH, and 45% and 48% with T1 3D Dixon VIBE in transverse and coronal orientation, respectively. Staging accuracy with T2 BLADE was significantly higher than with non-enhanced T1 FLASH and with T1 3D Dixon VIBE in transverse and coronal orientations (p < 0.0024). T2 HASTE had a significantly higher T-staging accuracy than transverse T1 3D-Dixon-VIBE (p < 0.0024). CONCLUSION: Transverse T2 BLADE images provide the highest accuracy for local tumour staging and should therefore be included in dedicated thoracic PET/MR protocols. As T1 3D Dixon VIBE images acquired for attenuation correction performed significantly worse, this sequence cannot be considered sufficiently accurate for local tumour staging in the thorax.

Evaluation of a simplified version of the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) comprising 5 joints (RAMRIS5).

OBJECTIVES: The objective of this study was to evaluate a simplified version of the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) reduced to five joints of the hand (RAMRIS5). METHODS: 94 patients with rheumatoid arthritis (62 female; age 59±12 years, range 25-83 years; disease duration 60±90 months (median: 22 months, first quartile: 7 months, third quartile: 66 months) from the REMISSION PLUS study cohort who had complete files on C-reactive protein (CRP) levels and Disease Activity Score of 28 joints (DAS28) and complete MRI of the clinical dominant hand at baseline and after one year under anti-rheumatic therapy (follow-up time 12.5±1.1 months) in a dedicated extremity MRI scanner at 0.2T were included in this retrospective study. RESULTS: There was a strong correlation between RAMRIS5 and the RAMRIS sum-score for all patients (r=0.87, p<0.001) at baseline and follow-up (r=0.87, p<0.001). Among the subscores there was a significant correlation between RAMRIS5 and RAMRIS-MCP (baseline: r=0.66, p<0.001; follow-up: r=0.74, p<0.001) as well as between RAMRIS5 and RAMRIS-wrist (baseline: r=0.72, p<0.001, follow-up: r=0.69, p<0.001) at baseline and follow-up. CONCLUSIONS: RAMRIS5, a modified shorter RAMRIS score based on five joints of the hand is a viable tool for semi-quantitative assessment of joint damage in RA. This abbreviated score might reduce the time needed for image analysis in MRI-controlled studies in RA and might facilitate the use of MRI in studies on therapy response assessment in RA.

MR-sequences for prostate cancer diagnostics: validation based on the PI-RADS scoring system and targeted MR-guided in-bore biopsy.

PURPOSE: This study evaluated the accuracy of MR sequences [T2-, diffusion-weighted, and dynamic contrast-enhanced (T2WI, DWI, and DCE) imaging] at 3T, based on the European Society of Urogenital Radiology (ESUR) scoring system [Prostate Imaging Reporting and Data System (PI-RADS)] using MR-guided in-bore prostate biopsies as reference standard. METHODS: In 235 consecutive patients [aged 65.7 ± 7.9 years; median prostate-specific antigen (PSA) 8 ng/ml] with multiparametric prostate MRI (mp-MRI), 566 lesions were scored according to PI-RADS. Histology of all lesions was obtained by targeted MR-guided in-bore biopsy. RESULTS: In 200 lesions, biopsy revealed prostate cancer (PCa). The area under the curve (AUC) for cancer detection was 0.70 (T2WI), 0.80 (DWI), and 0.74 (DCE). A combination of T2WI + DWI, T2WI + DCE, and DWI + DCE achieved an AUC of 0.81, 0.78, and 0.79. A summed PI-RADS score of T2WI + DWI + DCE achieved an AUC of 0.81. For higher grade PCa (primary Gleason pattern ≥ 4), the AUC was 0.85 for T2WI + DWI, 0.84 for T2WI + DCE, 0.86 for DWI + DCE, and 0.87 for T2WI + DWI + DCE. The AUC for T2WI + DWI + DCE for transitional-zone PCa was 0.73, and for the peripheral zone 0.88. Regarding higher-grade PCa, AUC for transitional-zone PCa was 0.88, and for peripheral zone 0.96. CONCLUSION: The combination of T2WI + DWI + DCE achieved the highest test accuracy, especially in patients with higher-grade PCa. The use of ≤2 MR sequences led to lower AUC in higher-grade and peripheral-zone cancers. KEY POINTS: • T2WI + DWI + DCE achieved the highest accuracy in patients with higher grade PCa • T2WI + DWI + DCE was more accurate for peripheral- than for transitional-zone PCa • DCE increased PCa detection accuracy in the peripheral zone • DWI was the leading sequence in the transitional zone.

Radiation exposure of the radiologist's eye lens during CT-guided interventions.

BACKGROUND: In the past decade the number of computed tomography (CT)-guided procedures performed by interventional radiologists have increased, leading to a significantly higher radiation exposure of the interventionalist's eye lens. Because of growing concern that there is a stochastic effect for the development of lens opacification, eye lens dose reduction for operators and patients should be of maximal interest. PURPOSE: To determine the interventionalist's equivalent eye lens dose during CT-guided interventions and to relate the results to the maximum of the recommended equivalent dose limit. MATERIAL AND METHODS: During 89 CT-guided interventions (e.g. biopsies, drainage procedures, etc.) measurements of eye lens' radiation doses were obtained from a dedicated dosimeter system for scattered radiation. The sensor of the personal dosimeter system was clipped onto the side of the lead glasses which was located nearest to the CT gantry. After the procedure, radiation dose (µSv), dose rate (µSv/min) and the total exposure time (s) were recorded. RESULTS: For all 89 interventions, the median total exposure lens dose was 3.3 µSv (range, 0.03-218.9 µSv) for a median exposure time of 26.2 s (range, 1.1-94.0 s). The median dose rate was 13.9 µSv/min (range, 1.1-335.5 µSv/min). CONCLUSION: Estimating 50-200 CT-guided interventions per year performed by one interventionalist, the median dose of the eye lens of the interventional radiologist does not exceed the maximum of the ICRP-recommended equivalent eye lens dose limit of 20 mSv per year.