[(18)F]FDG PET/MRI vs. PET/CT for whole-body staging in patients with recurrent malignancies of the female pelvis: initial results.

PURPOSE: To evaluate the diagnostic potential of PET/MRI with [(18)F]FDG in recurrent ovarian and cervical cancer in comparison to PET/CT. METHODS: A group of 19 patients with suspected recurrence of pelvic malignancies (ovarian cancer, 11 patients; cervical cancer, 8 patients) scheduled for an [(18)F]FDG PET/CT were subsequently enrolled for a PET/MRI. The scan protocol comprised: (1) a T1-W axial VIBE after contrast agent adminstration, (2) an axial T2-W HASTE, (3) a coronal TIRM, (4) an axial DWI, and dedicated MR sequences of the female pelvis including (5) a T1-W VIBE before contrast agent adminstration, (6) a sagittal T2-W TSE, and (7) a sagittal T1-W dynamic VIBE. The datasets (PET/CT, PET/MRI) were rated separately by two readers regarding lesion count, lesion localization, lesion conspicuity (four-point scale), lesion characterization (benign/malignant/indeterminate) and diagnostic confidence (three-point scale). All available data (histology, prior examinations, PET/CT, PET/MRI, follow-up examinations) served as standard of reference. Median values were compared using the Wilcoxon rank sum test. RESULTS: Metastatic lesions were present in 16 of the 19 patients. A total of 78 lesions (malignant, 58; benign, 20) were described. Both PET/CT and PET/MRI allowed correct identification of all malignant lesions and provided equivalent conspicuity (3.86 ± 0.35 for PET/CT, 3.91 ± 0.28 for PET/MRI; p > 0.05). Diagnostic confidence was significantly higher for PET/MRI in malignant (p < 0.01) and benign lesions (p < 0.05). CONCLUSION: Both PET/CT and PET/MRI offer an equivalently high diagnostic value for recurrent pelvic malignancies. PET/MRI offers higher diagnostic confidence in the discrimination of benign and malignant lesions. Considering the reduced radiation dose and superior lesion discrimination, PET/MRI may serve as a powerful alternative to PET/CT in the future.

Motility mapping as evaluation tool for bowel motility: initial results on the development of an automated color-coding algorithm in cine MRI.

PURPOSE: To develop and implement an automated algorithm for visualizing and quantifying bowel motility using cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: Four healthy volunteers as well as eight patients with suspected or diagnosed inflammatory bowel disease (IBD) underwent MR examinations on a 1.5T scanner. Coronal T2-weighted cine MR images were acquired in healthy volunteers without and with intravenous (i.v.) administration of butylscopolamine. In patients with IBD, cine MRI sequences were collected prior to standard bowel MRI. Bowel motility was assessed using an optical flow algorithm. The resulting motion vector magnitudes were presented as bowel motility maps. Motility changes after i.v. administration of butylscopolamine were measured in healthy volunteers. Inflamed bowel segments in patients were correlated with motility map findings. RESULTS: The acquisition of bowel motility maps was feasible in all subjects examined. In healthy volunteers butylscopolamine led to quantitatively measurable decrease in bowel motility (mean decrease of 59%; P = 0.171). In patients with IBD, visualization of bowel movement by color-coded motility mapping allowed for the detection of segments with abnormal bowel motility. Inflamed bowel segments could be identified by exhibiting a decreased motility. CONCLUSION: Our method is a feasible and promising approach for the assessment of bowel motility disorders.

3 Tesla high-resolution and delayed gadolinium enhanced MR imaging of cartilage (dGEMRIC) after autologous chondrocyte transplantation in the hip.

BACKGROUND: To evaluate the feasibility of 3 Tesla (T) high-resolution and gadolinium enhanced MRI of cartilage (dGEMRIC) in the thin and rounded hip cartilage of patients after acetabular matrix-based autologous chondrocyte transplantation (MACT). METHODS: Under general ethics approval, 24 patients were prospectively examined 6-31 months after acetabular MACT at 3T using high-resolution proton-density weighted (PDw) images (bilateral PD SPACE, 0.8 mm isotropic; unilateral PD-TSE coronal/sagittal, 0.8 × 0.8 resp. 0.5 × 0.5 × 2.5 mm) as well as T1 mapping (3D-FLASH, 0.78 mm isotropic) in dGEMRIC technique, and clinically scored. The cartilage transplant was evaluated using an adapted MOCART score (maximum 85 points). T1 relaxation times were measured independently by two radiologists. Here, regions of interest were placed manually in automatically calculated relaxation-maps, both in the transplant and adjacent healthy cartilage regions. Interobserver reliability was estimated by means of intraclass-correlation (ICC). RESULTS: The transplant was morphologically definable in the PDw images of 23 patients with a mean MOCART score of 69 points (60-80 points, SD 6.5). T1 maps showed a clear differentiation between acetabular and femoral cartilage, but correlation with PDw images was necessary to identify the transplant. Mean T1 relaxation times of the transplant were 616.3 ms (observer 1) resp. 610.1 ms (observer 2), and of adjacent healthy acetabular cartilage 574.5 ms (observer 1) resp. 604.9 ms (observer 2). Interobserver reliability of the relaxation times in the transplant was excellent (ICC-coefficient 0.88) and in adjacent healthy regions good (0.77). CONCLUSION: High-resolution PDw imaging with adapted MOCART scoring and dGEMRIC is feasible after MACT in the thin and rounded hip cartilage.

Does diffusion-weighted imaging improve therapy response evaluation in patients with hepatocellular carcinoma after radioembolization? comparison of MRI using Gd-EOB-DTPA with and without DWI.

PURPOSE: To investigate whether additional diffusion-weighted imaging (DWI) improves therapy response evaluation by Gd-EOB magnetic resonance imaging (MRI) in hepatocellular carcinoma (HCC) after radioembolization. MATERIALS AND METHODS: Fifty patients with radioembolization for HCC underwent gadobutrol and Gd-EOB MRI with DWI prior to and 30, 90, and 180 days after radioembolization. A combination of gadobutrol MRI, alpha-fetoprotein, and imaging follow-up served as the reference standard. Two radiologists reviewed Gd-EOB alone (Gd-EOB), DWI alone (DWI), and the combination of both (Gd-EOB+DWI) separately and in consensus using a 4-point-scale: 1 = definitely no tumor progression (TP), 2 = probably no TP, 3 = probably TP, 4 = definitely TP. Receiver operating characteristic (ROC) and kappa analysis were performed. RESULTS: Kappa values for Gd-EOB, DWI, and Gd-EOB+DWI ranged between 0.712 and 0.892 (P < 0.001). 30 days after radioembolization three out of 38 patients showed TP, which was missed by DWI in one case. No significant area under the curve (AUC) difference between Gd-EOB (1.0, P = 0.004), DWI (0.881, P = 0.030), and Gd-EOB+DWI (1.0, P = 0.004) was found (P = 0.320). 90 days after radioembolization six out of 28 patients showed TP, which was detected in one patient only by DWI and Gd-EOB+DWI. The AUC did not differ significantly (P = 0.319) between Gd-EOB (0.890, P = 0.004), DWI (1.0, P < 0.001), and Gd-EOB+DWI (1.0, P < 0.001). 180 days after radioembolization five patients showed TP, which in one case was missed by DWI. The AUC did not differ significantly (P1 = 0.322, P2 = 0.369, P3 = 0.350) between Gd-EOB (1.0, P = 0.003), DWI (0.913, P = 0.016), and Gd-EOB+DWI (0.963, P = 0.007). CONCLUSION: Additional DWI does not substantially improve therapy response evaluation by Gd-EOB MRI in HCC after radioembolization but proved helpful in single cases.

Therapy response assessment after radioembolization of patients with hepatocellular carcinoma--comparison of MR imaging with gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid and gadobutrol.

PURPOSE: To compare the utility of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA), a liver-specific magnetic resonance (MR) imaging contrast agent, versus gadobutrol for treatment response evaluation of hepatocellular carcinoma (HCC) after radioembolization. MATERIALS AND METHODS: This prospective study included 50 patients with HCC undergoing radioembolization. All patients underwent contrast-enhanced computed tomography (CT) and MR imaging with gadobutrol and Gd-EOB-DTPA on 2 consecutive days before radioembolization and 30 days, 90 days, 180 days, and 270 days after radioembolization. The standard of reference indicating tumor progression was CT combined with either α-fetoprotein or γ-glutamyltransferase. Gadobutrol-enhanced MR imaging, Gd-EOB-DTPA-enhanced MR imaging without late phase imaging (Gd-EOB-DTPA-), and Gd-EOB-DTPA-enhanced MR imaging with late phase imaging (Gd-EOB-DTPA+) were evaluated by 2 radiologists in consensus using a 4-point scale: 1 = definitely no tumor progression; 2 = probably no tumor progression; 3 = probably tumor progression; 4 = definitely tumor progression. Diagnostic accuracy was assessed with receiver operating characteristic analysis. RESULTS: Tumor progression was detected in 14 of 82 study visits according to the reference standard. Pairwise comparison of the area under the curve showed a tendency toward a larger area under the curve for Gd-EOB-DTPA+ compared with gadobutrol (P = .056). Sensitivity and specificity were higher in Gd-EOB-DTPA+ (0.929 and 0.971) than in Gd-EOB-DTPA- (0.786 and 0.941) or gadobutrol (0.643 and 0.956). In 2 cases, tumor progression was detected by Gd-EOB-DTPA+ and by an increase in α-fetoprotein, but not by CT, gadobutrol, or Gd-EOB-DTPA-. CONCLUSIONS: Gd-EOB-DTPA+ MR imaging was not inferior to gadobutrol-enhanced MR imaging in therapy response evaluation after radioembolization and may allow a more accurate detection of early HCC recurrence in single cases.

High and ultra-high b-value diffusion-weighted imaging in prostate cancer: a quantitative analysis.

BACKGROUND: Diffusion-weighted imaging (DWI) is routinely used in magnetic resonance imaging (MRI) of prostate cancer. However, the routine use of b values higher than 1000 s/mm(2) is not clear up to present. Moreover, the complex diffusion behavior of malignant and benign prostate tissues hampers precise predictions of contrast in DWI images and apparent diffusion coefficient (ADC) maps. PURPOSE: To quantitatively analyze DWI with different b values in prostate cancer and to identify b values best suitable for cancer detection. MATERIAL AND METHODS: Forty-one patients with histologically proven prostate cancer were examined with high resolution T2-weighted imaging and DWI at 3 Tesla. Five different b values (0, 800, 1000, 1500, 2000 s/mm(2)) were applied. ADC values of tumors and reference areas were measured on ADC maps derived from different pairs of b values. Furthermore, signal intensities of DW images of tumors and reference areas were measured. For analysis, contrast ratios of ADC values and signal intensities of DW images were calculated and compared. RESULTS: No significant differences were found between contrast ratios measured on ADC maps of all analyzed b value pairs (P = 0.43). Contrast ratios calculated from signal intensities of DW images were highest at b values of 1500 and 2000 s/mm(2) and differed significantly from contrast ratios at b values of 800 and 1000 s/mm(2) (P < 0.01). CONCLUSION: Whereas contrast in ADC maps does not significantly change with different b values, contrast ratios of DW images are significantly higher at b-values of 1500 and 2000 s/mm(2) in comparison to b values of 800 and 1000 s/mm(2). Therefore, diagnostic performance of DWI in prostate cancer might be increased by application of b values higher than 1000 s/mm(2).

Aspects of postoperative magnetic resonance imaging of patients with avascular necrosis of the femoral head, treated by advanced core decompression.

OBJECTIVE: To analyze remodeling processes after advanced core decompression (ACD) in patients with avascular femoral head necrosis by means of 3T MRI and to identify indicators for clinical outcome considering the defect size and characteristics of the bone graft and of the neighboring regeneration tissue. MATERIALS AND METHODS: Thirty-four hips, with preexisting preoperative MRIs in 21 cases, were examined 1-34 months (mean 12.7) postoperatively by 3T MRI. The volume of necrosis was measured manually pre- and postoperatively to calculate absolute as well as percentage necrosis reduction. The signal intensity of the bone graft was quantified using a 4-point scale. Border phenomena between the bone graft and bone were described and classified into groups. Wilcoxon sign-rank test was used to identify correlations between the analyzed items and clinical signs of femoral head collapse after a mean follow-up time of 28.6 months (10.4-46.8). RESULTS: Mean percentage reduction of necrosis was significantly higher in asymptomatic patients (59.36%) compared to patients with signs of femoral head collapse (28.78%, p = 0.008). Signal intensity of the bone graft increased in T1w and T2w TIRM sequences over time after surgery and was significantly higher in asymptomatic patients. Five border phenomena between the bone graft and healthy bone were identified. Among them, the so-called "rail sign" representing three layers of remodeling tissue correlated with the histological observations. CONCLUSION: A variety of border phenomena representing remodeling processes have been described using 3T MRI. Beneath the percentage amount of necrosis reduction, we identified the signal intensity of the bone graft as an indicator for clinical outcome.

Usefulness of metal artifact reduction with WARP technique at 1.5 and 3T MRI in imaging metal-on-metal hip resurfacings.

OBJECTIVE: To evaluate the usefulness of the metal artifact reduction technique "WARP" in the assessment of metal-on-metal hip resurfacings at 1.5 and 3T in the context of image quality and imaging speed. MATERIALS AND METHODS: Nineteen patients (25 hip resurfacings) were randomized for 1.5 and 3T MRI, both including T1 and T2 turbo spin-echo as well as turbo inversion recovery magnitude sequences with and without view angle tilting and high bandwidth. Additional 3T sequences were acquired with a reduced number of averages and using the parallel acquisition technique for accelerating imaging speed. Artifact size (diameter, area), image quality (5-point scale) and delineation of anatomical structures were compared among the techniques, sequences and field strengths using the Wilcoxon sign-rank and paired t-test with Bonferroni correction. RESULTS: At both field strengths, WARP showed significant superiority over standard sequences regarding image quality, artifact size and delineation of anatomical structures. At 3T, artifacts were larger compared to 1.5T without affecting diagnostic quality, and scanning time could be reduced by up to 64 % without quality degradation. CONCLUSION: WARP proved useful in imaging metal-on-metal hip resurfacings at 1.5T as well as 3T with better image quality surrounding the implants. At 3T imaging could be considerably accelerated without losing diagnostic quality.

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

OBJECTIVES: To compare [(18)F]FDG PET/MRI with PET/CT for the assessment of bone lesions in oncologic patients. METHODS: This prospective study included 67 patients with solid tumours scheduled for PET/CT with [(18)F]FDG who also underwent a whole-body PET/MRI scan. The datasets (PET/CT, PET/MRI) were rated by two readers regarding lesion conspicuity (four-point scale) and diagnostic confidence (five-point scale). Median scores were compared using the Wilcoxon test. RESULTS: Bone metastases were present in ten patients (15%), and benign bone lesions in 15 patients (22%). Bone metastases were predominantly localized in the pelvis (18 lesions, 38%) and the spine (14 lesions, 29%). Benign bone lesions were exclusively osteosclerotic and smaller than the metastases (mean size 6 mm vs. 23 mm). While PET/CT allowed identification of 45 of 48 bone metastases (94%), PET/MRI allowed identification of all bone metastases (100%). Conspicuity of metastases was high for both modalities with significantly better results using PET/MRI (p < 0.05). Diagnostic confidence in lesion detection was high for both modalities without a significant difference. In benign lesions, conspicuity and diagnostic confidence were significantly higher with PET/CT (p < 0.05). CONCLUSIONS: [(18)F]FDG PET/MRI shows high potential for the assessment of bone metastases by offering superior lesion conspicuity when compared to PET/CT. In hypersclerotic, benign bone lesions PET/CT still sets the reference. KEY POINTS: • PET/MRI and PET/CT are of equal value for the identification of disease-positive patients • PET/MRI offers higher lesion conspicuity as well as diagnostic confidence • PET/MRI is an attractive new alternative for the assessment of bone metastases.

Seven-Tesla MRI of the female pelvis.

OBJECTIVES: The aim of this study was to investigate the feasibility of 7-T contrast-enhanced MR imaging of the female pelvis. METHODS: Ten healthy female volunteers were examined on a 7-T whole-body MR system utilising a custom-built eight-channel transmit/receive radiofrequency body coil. The examination protocol included (1) T1-weighted fat-saturated 2D spoiled gradient echo (FLASH), (2) dynamic T1-weighted fat-saturated 3D FLASH, and (3) T2-weighted TSE sequences. For qualitative image analysis pelvic anatomy, uterine zonal anatomy and image impairment due to artefacts was assessed using a five-point scale. For quantitative analysis contrast ratios between the junctional zone and myometrium were obtained for T2-weighted MRI. RESULTS: Two-dimensional FLASH MRI offered the best overall image quality (meancontrast-enhanced 4.9) and highest tissue contrast (meancontrast-enhanced 4.7). T2-weighted TSE imaging provided a moderate to high conspicuity of the uterine zonal anatomy with mean scores ranging from 3.5 for endometrium to 4.65 for myometrium. Overall image impairment was rated strongest for T2-weighted MRI (2.9) and least for 2D FLASH MRI (mean 4.2). CONCLUSION: This study demonstrated the feasibility of 7-T T1-weighted MRI of the female pelvis and current constraints associated with T2-weighted MRI. KEY POINTS: • Dynamic contrast-enhanced female pelvis MR imaging at 7 T is feasible. • Unenhanced T1-weighted MRI offers inherent hyperintense delineation of pelvic arterial vasculature. • Two-dimensional FLASH MRI provided best overall image quality and least artefact impairment.

Biliary complications after liver transplantation: addition of T1-weighted images to MR cholangiopancreatography facilitates detection of cast in biliary cast syndrome.

PURPOSE: To evaluate the diagnostic performance of T2-weighted magnetic resonance (MR) cholangiopancreatography pulse sequences in comparison with MR cholangiopancreatography sequences combined with nonenhanced T1-weighted images in the detection of biliary cast syndrome in liver transplant recipients. MATERIALS AND METHODS: This retrospective study was conducted in accordance with the declaration of Helsinki. Institutional review board approval was obtained. MR images in 95 patients who were examined after liver transplantation and who presented with symptoms of biliary obstruction were examined. Two separate sets of images, MR cholangiopancreatograms and MR cholangiopancreatograms plus T1-weighted images, were evaluated independently by three readers. Sensitivities, specificities, and positive and negative predictive values for biliary cast syndrome were calculated, and receiver operating characteristic curves were generated. The results of endoscopic retrograde cholangiopancreatography served as the reference standard. To determine interobserver agreement, κ values were calculated. RESULTS: Cast appeared hyperintense on nonenhanced T1-weighted images. Sensitivities for T2-weighted MR cholangiopancreatography data alone were 0.65, 0.70, and 0.55 for the three readers. Adding unenhanced T1-weighted images resulted in sensitivities of 0.95, 0.90, and 0.90, respectively. Specificities for MR cholangiopancreatography alone and for MR cholangiopancreatography plus T1-weighted images were high on average (0.98, 0.97, and 0.97 vs 1.0 for all readers, respectively). Interobserver agreement was good for T2-weighted MR cholangiopancreatography (κ for readers 1 and 2 = 0.589, κ for readers 2 and 3 = 0.593, κ for readers 1 and 3 = 0.734) and was excellent for MR cholangiopancreatography plus T1-weighted images (κ for readers 1 and 2 = 0.806, κ for readers 2 and 3 = 0.881, κ for readers 1 and 3 = 0.848). CONCLUSION: The combination of T2-weighted MR cholangiopancreatography and T1-weighted imaging yields higher diagnostic performance than MR cholangiopancreatography alone. Therefore, readers evaluating liver MR images with regard to biliary complications after liver transplantation should also look at the bile ducts on unenhanced T1-weighted images, as biliary cast might be more easily depicted on these images.

Size-based clinical response evaluation is insufficient to assess clinical response of sarcomas treated with isolated limb perfusion with TNF-α and melphalan.

BACKGROUND: The clinical assessment of the response of sarcomas to preoperative treatment is usually defined using size-based evaluation standards. For nonresectable sarcomas, hyperthermic isolated limb perfusion with TNF-α and melphalan (TM-ILP) yields high response rates. Based on our experience, we assume that anatomic radiological response criteria are insufficient to assess the degree of regression after TM-ILP. METHODS: The clinical response of 35 sarcomas to TM-ILP was assessed by unidimensional, bidimensional, and tridimensional size-based anatomical criteria, and responders were identified according to the established thresholds. The same tumors were investigated for pathological response according to the Salzer-Kuntschik regression scale (>90% devitalization) and reviewed for cystic degeneration, hemorrhage, and predominant necrotic or fibrosclerotic regression phenotype. RESULTS: None of the clinical response criteria were able to reliably identify the pathologic responders. The extent of size changes showed no association with the pathological degree of regression. The number of clinical responders was low compared with the number of pathological responders (RECIST N = 1, WHO N = 3, volumetry N = 3, pathology N = 19). The occurrence of hemorrhage and/or cystic degeneration was more frequently observed in predominant necrotic sarcomas and was associated with an increase in tumor size after TM-ILP. Furthermore, we identified the fibrosclerotic phenotype of regression to be more significantly strongly associated with posttherapeutic shrinkage than necrosis. CONCLUSIONS: Size-based clinical response evaluation is insufficient to assess clinical response in TM-ILP-treated sarcomas. The size changes of tumors after therapy reflect the type of regression rather than the extent of destruction.

Selective internal radiation therapy of hepatocellular carcinoma: potential hepatopulmonary shunt reduction after sorafenib administration.

Sorafenib, a protein kinase inhibitor, is a systemic drug that has been licensed for the treatment of hepatocellular carcinoma (HCC). This retrospective study assessed whether the administration of sorafenib can result in a reduction of the hepatopulmonary shunt (HPS) before selective internal radiation therapy (SIRT). After exclusion from SIRT because of high HPS, computed tomography scan indicated a shunt reduction in seven patients with HCC receiving sorafenib. Repeated measurements revealed HPS reduction (from 26.5% to 7.5% on average), and subsequent SIRT became possible. In conclusion, sorafenib may reduce HPS in patients with advanced HCC in some cases.

Accuracy and variability of right ventricular volumes and mass assessed by dual-source computed tomography: influence of slice orientation in comparison to magnetic resonance imaging.

OBJECTIVE: To evaluate the accuracy and variability of right ventricular (RV) volumes and mass using dual-source computed tomography (DSCT) and the influence of slice orientation in comparison to cardiac magnetic resonance imaging (CMR). METHODS: In 33 patients undergoing cardiac DSCT and CMR, RV parameters were calculated using the short-axis (DSCT, CMR) and axial orientation (DSCT). Intra- and interobserver variability were assessed by Bland-Altman analysis. RESULTS: Short-axis orientation: RV parameters of the two techniques were not statistically different. Axial orientation: RV volumes and mass were significantly overestimated compared with short-axis parameters whereas EF was similar. The short-axis approach resulted in low variability, although the axial orientation had the least amount of intra- and interobserver variability. CONCLUSION: RV parameters can be more accurately assessed by DSCT compared with CMR using short-axis slice orientation. RV volumes and mass are significantly higher using axial compared with short-axis slices, whereas EF is unaffected. RV parameters derived from both approaches yield high reproducibility.

Renal imaging at 7 Tesla: preliminary results.

OBJECTIVE: To investigate the feasibility of 7T MR imaging of the kidneys utilising a custom-built 8-channel transmit/receive radiofrequency body coil. METHODS: In vivo unenhanced MR was performed in 8 healthy volunteers on a 7T whole-body MR system. After B(0) shimming the following sequences were obtained: 1) 2D and 3D spoiled gradient-echo sequences (FLASH, VIBE), 2) T1-weighted 2D in and opposed phase 3) True-FISP imaging and 4) a T2-weighted turbo spin echo (TSE) sequence. Visual evaluation of the overall image quality was performed by two radiologists. RESULTS: Renal MRI at 7T was feasible in all eight subjects. Best image quality was found using T1-weighted gradient echo MRI, providing high anatomical details and excellent conspicuity of the non-enhanced vasculature. With successful shimming, B(1) signal voids could be effectively reduced and/or shifted out of the region of interest in most sequence types. However, T2-weighted TSE imaging remained challenging and strongly impaired because of signal heterogeneities in three volunteers. CONCLUSION: The results demonstrate the feasibility and diagnostic potential of dedicated 7T renal imaging. Further optimisation of imaging sequences and dedicated RF coil concepts are expected to improve the acquisition quality and ultimately provide high clinical diagnostic value.

Tumor vascularization and histopathologic regression of soft tissue sarcomas treated with isolated limb perfusion with TNF-α and melphalan.

BACKGROUND: Isolated limb perfusion (TM-ILP) achieves high response rates in soft tissue sarcomas (STS). Some tumors show an insufficient association between radiological and pathological response. We investigated STS after TM-ILP with a primary emphasis on histologic regression patterns. METHODS: In 53 patients with STS, TM-ILP with subsequent tumor resection was performed. Regression was assessed by the Salzer-Kuntschik regression scale. Microvessel density (MVD) of primary biopsies of 37 patients was determined by immunohistochemistry. Tumor regression was correlated with MVD of primary biopsies and other clinico-pathological parameters. RESULTS: Regression presented mainly as necrosis or fibrosis/sclerosis upon histopathology. MFH, leiomyosarcoma, or clear cell sarcoma (CCS) responded well; whereas liposarcomas, synovial sarcomas, or MPNST were poor responders. MFH often had abundant necrosis; while other STS mainly presented with fibrosis/sclerosis. MVD had no influence on regression grade but modulated histologic regression patterns. Excellent regression demonstrated a trend toward an association with improved survival and local control. CONCLUSION: TM-ILP yielded high response rates in STS. Regression after TM-ILP exhibits MVD-dependent histopathologic patterns and variable efficacy in different sarcoma types. Complete regression seems to be a favorable prognostic factor. A concerted consideration of histopathology and clinical findings may contribute to a better clinical assessment of regression after TM-ILP.

Comparison of different MRCP techniques for the depiction of biliary complications after liver transplantation.

OBJECTIVE: Biliary strictures after liver transplantation are common. We aimed to compare different magnetic resonance cholangiopancreatography (MRCP) sequences with regard to their diagnostic accuracy in depicting anastomotic stenoses (AST), ischaemic-type biliary lesions (ITBL) and cholelithiasis. METHODS: In patients with clinically suspected biliary obstruction after liver transplantation, MRCP was performed at 1.5 T using two-dimensional (2D) single-shot RARE, 2D T2-weighted (T2w) HASTE, 2D TrueFISP and 3D T2w TSE RESTORE sequences. The presence and localisation of lesions were assessed for each sequence independently and all sequences together. Endoscopic retrograde cholangiopancreatography (ERCP) served as the "gold standard". RESULTS: Biliary strictures were detected with a sensitivity of 96% by MRCP and most accurately depicted when all sequences were analysed together. AST was visualised with highest sensitivity on TrueFISP and 3D T2w TSE sequences (79%). For ITBL highest sensitivity was found with the HASTE sequence (81%). Highest sensitivity for filling defects was revealed by the 3D T2w TSE sequence (54%). Receiver operating characteristic (ROC) curve/area under the curve (AUC) analysis revealed the best results for the 3D T2w TSE sequence. CONCLUSION: Our results underline the value of different MRCP sequence types for the depiction of biliary lesions. A clinical protocol consisting of different sequences may be helpful depending on the clinical question and the likely underlying abnormality.

Water-equivalent oral contrast agents in dual-modality PET/computed tomography scanning: does a little barium make the difference?

OBJECTIVE: To retrospectively evaluate the performance of two water-equivalent oral contrast agents [locust bean gum (LBG)-mannitol and VoLumen] concerning their potential to distend the bowel while avoiding contrast-associated artifacts in PET/computed tomography. METHODS: PET/computed tomography examinations of 30 patients with two different oral contrast agents were reviewed. Bowel distension, intraluminal density, and potential contrast-associated artifacts were assessed for stomach, jejunum, and ileum. Statistical significance was tested by Student's t-test. RESULTS: Distension was slightly better in the stomach with VoLumen as compared with LBG-mannitol whereas LBG-mannitol was found to slightly better distend the small bowel. This difference proved to be statistically significant for the jejunum. A statistically significant difference was detected for intraluminal density with higher densities for VoLumen. This difference, however, did not result in a higher incidence of PET artifacts with VoLumen. CONCLUSION: LBG-mannitol provides excellent bowel distension, thereby avoiding contrast-associated PET artifacts. If this solution is not available, VoLumen provides a satisfactory alternative for bowel distension without relevant PET artifacts.

Individual kidney blood flow measured with contrast-enhanced first-pass perfusion MR imaging.

UNLABELLED: The study design was HIPAA-compliant and approved by the Institutional Review Board, with all participants providing signed informed consent prior to the study. The purpose of this study was to prospectively evaluate the feasibility of determining renal blood flow (RBF) by using a technique based on intravenous administration of gadolinium chelate and evaluation of first-pass gadolinium chelate perfusion by using highly accelerated three-dimensional (3D) gradient-echo magnetic resonance (MR) imaging of the kidney in freely breathing subjects. Flow is determined with Kety-Schmidt formalism by modeling the uptake of gadolinium chelate in the kidney prior to its leaving through the venous system. Validation of the gadolinium chelate perfusion technique is based on comparison of values determined for participants with phase-contrast gradient-echo imaging. The model fit to the measured data is excellent over the first 7-8 seconds of gadolinium chelate uptake and diverges after its appearance in the renal vein. The perfusion data analysis technique showed less than 10% interobserver variation. The average difference between phase-contrast and gadolinium chelate perfusion measurements was 0.08 mL/sec (95% confidence interval: -3.73, 3.58) for left and right kidneys. This study demonstrates feasibility of the gadolinium chelate perfusion method for RBF measurement and discusses potential applications. SUPPLEMENTAL MATERIAL: http://radiology.rsnajnls.org/cgi/content/full/246/1/241/DC1.