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Objectives: To perform a systematic review and meta-analysis of published data to evaluate the utility of chemical shift imaging (CSI) for differentiating between adrenal adenomas and non-adenomas., Methods: A systematic search of the MEDLINE, Web of Science Core Collection, EMBASE and Cochrane Central Register of Controlled Trials electronic databases was performed. The methodological quality of the included studies was assessed by using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) tool. A bivariate random effect model was used to determine summary and subgroup sensitivity and specificity and calculate summary receiver operating characteristic curves (SROC)., Results: Eighteen studies with 1138 patients and 1280 lesions (859 adenomas, 421 non-adenomas) in total were included. In addition to summary analysis, quantitative analyses of the adrenal signal intensity index (SII, 978 lesions, 14 studies), adrenal-to-spleen ratio (ASR; 394 lesions, 7 studies) and visual analysis (560 lesions, 5 studies) were performed. The resultant data showed considerable heterogeneity (inconsistency index I 2 of 94%, based on the diagnostic odds ratio, DOR). The pooled sensitivity of CSI for adenoma was 0.94 [95% confidence interval (CI) 0.88-0.97] and pooled specificity was 0.95 (95% CI 0.89-0.97). The area (AUC) under the SROC curve was 0.98 (95% CI 0.96-0.99). The corresponding AUCs were 0.98, 0.99 and 0.95 for SII, ASR and visual evaluation, respectively., Conclusion: CSI has high sensitivity, specificity and accuracy for adrenal adenoma. Diagnostic performance does not improve when quantitative indices are used., Key Points: • Inclusion of CSI in abdominal MRI protocols provides an effective solution for classifying adrenal masses discovered on MR exams • Visual evaluation of adrenal CSI is sufficient; use of quantitative indices does not improve diagnostic accuracy.

Objectives: We compared the transperineal MRI/ultrasound-fusion biopsy (fusPbx) to transrectal systematic biopsy (sysPbx) in patients with previously negative biopsy and investigated the prediction of tumour aggressiveness with regard to radical prostatectomy (RP) specimen., Material and Methods: A total of 710 patients underwent multiparametric magnetic resonance imaging (mpMRI), which was evaluated in accordance with Prostate Imaging Reporting and Data System (PI-RADS). The maximum PI-RADS (maxPI-RADS) was defined as the highest PI-RADS of all lesions detected in mpMRI. In case of proven prostate cancer (PCa) and performed RP, tumour grading of the biopsy specimen was compared to that of the RP. Significant PCa (csPCa) was defined according to Epstein criteria., Results: Overall, scPCa was detected in 40% of patients. The detection rate of scPCa was 33% for fusPbx and 25% for sysPbx alone (p < 0.005). Patients with a maxPI-RADS ≥3 and a prostate specific antigen (PSA)-density ≥0.2 ng/mL2 harboured more csPCa than those with a PSA-density < 0.2 ng/mL2 (41% [33/81] vs. 20% [48/248]; p < 0.001). Compared to the RP specimen (n = 140), the concordance of tumour grading was 48% (γ = 0.57), 36% (γ = 0.31) and 54% (γ = 0.6) in fusPbx, sysPbx and comPbx, respectively., Conclusions: The combination of fusPbx and sysPbx outperforms both biopsy modalities in patients with re-biopsy. Additionally, the PSA-density may represent a predictor for csPCa in patients with maxPI-RADS ≥3., (© 2018 S. Karger AG, Basel.)

Objectives: To determine the value of 18 F-FDG-PET/MRI in the diagnosis and management of patients with pelvic recurrence of rectal cancer., Methods: Forty-four patients (16 women, 28 men) with a history of rectal cancer who received FDG-PET/MRI between June 2011 and February 2017 at our institution were retrospectively enrolled. Three patients received two FDG-PET/MRIs; thus a total of 47 examinations were included. Pelvic recurrence was confirmed either with histology (n = 27) or imaging follow-up (n = 17) (> 4 months). Two readers (one radiologist, one nuclear medicine physician) interpreted the images in consensus. Pelvic lesions were assessed regarding FDG uptake and morphology. Sensitivity, specificity, positive and negative predictive values as well as accuracy of PET/MRI in detecting recurrence were determined., Results: In 47 FDG-PET/MRIs 30 suspicious pelvic lesions were identified, 29 of which were malignant. Two patients underwent resection and had histologically proven pelvic recurrence without showing suspicious findings on FDG-PET/MRI. Changes in management due to FDG-PET/MRI findings had been implemented in eight patients. Eighty per cent (16/20) of resected patients had histologically negative resection margins (R0), one patient had uncertain resection margins. Sensitivity of FDG-PET/MRI in detecting recurrence was 94%, specificity 94%, positive/negative predictive value and accuracy were 97%, 90% and 94%, respectively., Conclusions: FDG-PET/MRI is a valuable tool in the diagnosis and staging of pelvic recurrence in patients with rectal cancer., Key Points: • Metabolic information obtained from PET coupled with excellent soft tissue contrast from MRI could facilitate detection of rectal cancer recurrence and assist in treatment planning. • PET/MRI demonstrates high sensitivity and specificity for the diagnosis of local recurrence of rectal cancer • PET/MRI led to alterations in management in 18.2% of patients.

Introduction: Targeted biopsy of tumour-suspicious lesions detected in multiparametric magnetic resonance imaging (mpMRI) plays an increasing role in the active surveillance (AS) of patients with low-risk prostate cancer (PCa). The aim of this study was to compare MRI/ultrasound-fusion biopsy (fusPbx) with systematic biopsy (sysPbx) in patients undergoing biopsy for AS., Methods: Patients undergoing mpMRI and transperineal fusPbx combined with transrectal sysPbx (comPbx) as surveillance biopsy were investigated. The detection of Gleason score upgrading and reclassification according to Prostate Cancer Research International Active Surveillance criteria were evaluated., Results: Eighty-three patients were enrolled. PCa upgrading was detected in 39% by fusPbx and in 37% by sysPbx (p = 1.0). The percentage of patients who were reclassified in fusPbx and sysPbx (p = 0.45) were 64 and 59% respectively. ComPbx detected more frequently tumour upgrading than fusPbx (71 vs. 64%, p = 0.016) and sysPbx (71 vs. 59%, p < 0.001) and more patients had to be reclassified after comPbx than after fusPbx or sysPbx alone., Conclusions: The combination of fusPbx and sysPbx outperforms both modalities alone with regard to the detection of upgrading and reclassification in patients under AS. Because a high missing rate of significant PCa still exists in both biopsy modalities, a combination of fusPbx and sysPbx should be recommended in these patients., (© 2018 S. Karger AG, Basel.)

Objectives: The study aimed to evaluate the prediction of Prostate Imaging Reporting and Data System (PI-RADS) with respect to the prostate cancer (PCa) detection rate and tumor aggressiveness in magnetic resonance imaging (MRI)/ultrasound-fusion-biopsy (fusPbx) and in systematic biopsy (sysPbx)., Materials and Methods: Six hundred and twenty five patients undergoing multiparametric MRI were investigated. MRI findings were classified using PI-RADS v1 or v2. All patients underwent fusPbx combined with sysPbx (comPbx). The lesion with the highest PI-RADS was defined as maximum PI-RADS (maxPI-RADS). Gleason Score ≥7 (3 + 4) was defined as significant PCa., Results: The overall PCa detection rate was 51% (n = 321; 39% significant PCa). The detection rate was 43% in fusPbx (n = 267; 34% significant PCa) and 36% in sysPbx (n = 223; 27% significant PCa). Nine percentage of significant PCa were detected by sysPbx alone. A total of 1,162 lesions were investigated. The detection rate of significant PCa in lesions with PI-RADS 2, 3, 4, and 5 were 9% (18/206), 12% (56/450), 27% (98/358), and 61% (90/148) respectively. maxPI-RADS ≥4 was the strongest predictor for the detection of significant PCa in comPbx (OR 2.77; 95% CI 1.81-4.24; p < 0.005)., Conclusions: maxPI-RADS is the strongest predictor for the detection of significant PCa in comPbx. Due to a high detection rate of additional significant PCa in sysPbx, fusPbx should still be combined with sysPbx., (© 2017 S. Karger AG, Basel.)

Objective: To compare multiparametric magnetic resonance imaging (mpMRI) of the prostate and histological findings of both targeted MRI/ultrasonography-fusion prostate biopsy (PBx) and systematic PBx with final histology of the radical prostatectomy (RP) specimen., Patients and Methods: A total of 105 patients with prostate cancer (PCa) histopathologically proven using a combination of fusion Pbx and systematic PBx, who underwent RP, were investigated. All patients had been examined using mpMRI, applying the European Society of Urogenital Radiology criteria. Histological findings from the RP specimen were compared with those from the PBx. Whole-mount RP specimen and mpMRI results were directly compared by a uro-pathologist and a uro-radiologist in step-section analysis., Results: In the 105 patients with histopathologically proven PCa by combination of fusion PBx and systematic PBx, the detection rate of PCa was 90% (94/105) in fusion PBx alone and 68% (72/105) in systematic PBx alone (P = 0.001). The combination PBx detected 23 (22%) Gleason score (GS) 6, 69 (66%) GS 7 and 13 (12%) GS ≥8 tumours. Fusion PBx alone detected 25 (26%) GS 6, 57 (61%) GS 7 and 12 (13%) GS ≥8 tumours. Systematic PBx alone detected 17 (24%) GS 6, 49 (68%) GS 7 and 6 (8%) GS ≥8 tumours. Fusion PBx alone would have missed 11 tumours (4% [4/105] of GS 6, 6% [6/105] of GS 7 and 1% [1/105] of GS ≥8 tumours). Systematic PBx alone would have missed 33 tumours (10% [10/105] of GS 6, 20% [21/105] of GS 7 and 2% [2/105] of GS ≥8 tumours). The rates of concordance with regard to GS between the PBx and RP specimen were 63% (n = 65), 54% (n = 56) and 75% (n = 78) in fusion, systematic and combination PBx (fusion and systematic PBx combined), respectively. Upgrading of the GS between PBx and RP specimen occurred in 33% (n = 34), 44% (n = 46) and 18% (n = 19) in fusion, systematic and combination PBx, respectively. γ-correlation for detection of any cancer was 0.76 for combination PBx, 0.68 for fusion PBx alone and 0.23 for systematic PBx alone. In all, 84% (n = 88) of index tumours were identified by mpMRI; 86% (n = 91) of index lesions on the mpMRI were proven in the RP specimen., Conclusions: Fusion PBx of tumour-suspicious lesions on mpMRI was associated with a higher detection rate of more aggressive PCa and a better tumour prediction in final histopathology than systematic PBx alone; however, combination PBx had the best concordance for the prediction of GS. Furthermore, the additional findings of systematic PBx reflect the multifocality of PCa, therefore, the combination of both biopsy methods would still represent the best approach for the prediction of the final tumour grading in PCa., (© 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.)

Purpose: To assess the effect of proton magnetic resonance spectroscopy imaging (MRSI) on the accuracy of multiparametric magnetic resonance imaging (mpMRI) at 3 T for prostate cancer detection., Materials and Methods: Thirty-four patients with prostate cancer were included in this retrospective study. All patients underwent preoperative mpMRI on a 3-T scanner before radical prostatectomy. Magnetic resonance imaging evaluation was based on the prostate imaging-reporting and data system classification system. The accuracy of mpMRI with and without MRSI was determined using receiver operating characteristic analysis, with histology as the reference standard., Results: Multiparametric MRI including MRSI had a sensitivity of 57.0% and a specificity of 89.2% for sextant-based cancer detection. Multiparametric MRI without MRSI had a sensitivity of 58.1% and a specificity of 87.4%. There was no significant difference regarding the accuracy of mpMRI with and without MRSI (P = 0.48)., Conclusion: The addition of MRSI does not improve the accuracy of 3 T mpMRI for sextant localization of prostate cancer.

Objective: To assess the diagnostic value of PET/MR (positron emission tomography/magnetic resonance imaging) with FDG (18F-fluorodeoxyglucose) for lymph node staging in head and neck cancer., Materials and Methods: This prospective study was approved by the local ethics committee; all patients signed informed consent. Thirty-eight patients with squamous cell carcinoma of the head and neck region underwent a PET scan on a conventional scanner and a subsequent PET/MR on a whole-body hybrid system after a single intravenous injection of FDG. The accuracy of PET, MR and PET/MR for lymph node metastases were compared using receiver operating characteristic (ROC) analysis. Histology served as the reference standard., Results: Metastatic disease was confirmed in 16 (42.1%) of 38 patients and 38 (9.7%) of 391 dissected lymph node levels. There were no significant differences between PET/MR, MR and PET and MR (p>0.05) regarding accuracy for cervical metastatic disease. Based on lymph node levels, sensitivity and specificity for metastatic involvement were 65.8% and 97.2% for MR, 86.8% and 97.0% for PET and 89.5% and 95.2% for PET/MR., Conclusions: In head and neck cancer, FDG PET/MR does not significantly improve accuracy for cervical lymph node metastases in comparison to MR or PET., (Copyright © 2014. Published by Elsevier Ireland Ltd.)

Object: To evaluate the feasibility of positron emission tomography/magnetic resonance imaging (PET/MR) with (18)fluoro-2-deoxyglucose (FDG) for therapy response evaluation of malignant lymphoma., Materials and Methods: Nine patients with malignant lymphoma who underwent FDG-PET/MR before and after chemotherapy were included in this retrospective study. Average time between the two scans was 70 days. The scans were evaluated independently by two nuclear medicine physicians. The Ann Arbor classification was used to describe lymphoma stage. Furthermore, the readers also rated PET image quality using a five point scale. Weighted kappa (κ) was used to calculate interrater agreement., Results: The initial scan showed foci of increased FDG uptake in all patients, with Ann Arbor stage varying between I and IV. In the follow-up examination, all but one patient showed complete response to chemotherapy. PET image quality was rated as very good or excellent for all scans. Interrater agreement was excellent regarding Ann Arbor stage (κ = 0.97) and good regarding image quality (κ = 0.41)., Conclusion: PET/MR shows promising initial results for therapy response evaluation in lymphoma patients.

Purpose: To evaluate the feasibility of PET/MRI (positron emission tomography/magnetic resonance imaging) with FDG ((18)F-fluorodeoxyglucose) for initial staging of head and neck cancer., Methods: The study group comprised 20 patients (16 men, 4 women) aged between 52 and 81 years (median 64 years) with histologically proven squamous cell carcinoma of the head and neck region. The patients underwent a PET scan on a conventional scanner and a subsequent PET/MRI examination on a whole-body hybrid system. FDG was administered intravenously prior to the conventional PET scan (267-395 MBq FDG, 348 MBq on average). The maximum standardized uptake values (SUV(max)) of the tumour and of both cerebellar hemispheres were determined for both PET datasets. The numbers of lymph nodes with increased FDG uptake were compared between the two PET datasets., Results: No MRI-induced artefacts where observed in the PET images. The tumour was detected by PET/MRI in 17 of the 20 patients, by PET in 16 and by MRI in 14. The PET/MRI examination yielded significantly higher SUV(max) than the conventional PET scanner for both the tumour (p < 0.0001) and the cerebellum (p = 0.0009). The number of lymph nodes with increased FDG uptake detected using the PET dataset from the PET/MRI system was significantly higher the number detected by the stand-alone PET system (64 vs. 39, p = 0.001)., Conclusion: The current study demonstrated that PET/MRI of the whole head and neck region is feasible with a whole-body PET/MRI system without impairment of PET or MR image quality.

Purpose: Retrospective, surrogate marker-based studies have found inconsistent associations between systemic iron overload (SIO) and adverse outcome in patients undergoing allogeneic stem cell transplantation (allo-SCT). As a consequence, the impact of SIO in this context remains under debate. The aim of this study was to test whether the objective pretransplant quantification of liver-iron content (LIC) by magnetic resonance imaging (MRI) could circumvent these limitations and conclusively define the prognostic relevance of SIO., Experimental Design: The correlation between pretransplant LIC and surrogate parameters as well as the impact of SIO on posttransplant outcome was assessed within an observational study of patients (n = 88) with either myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) undergoing allo-SCT., Results: Ferritin levels of 1,000 ng/mL or more provided only poor specificity (31.8%) for predicting elevated LIC (≥125 μmol/g) and even higher thresholds (≥2,500 ng/mL) lacked an association with nonrelapse mortality (NRM). In contrast, LIC 125 μmol/g or more was a significant risk factor for NRM in uni- and multivariate analysis (HR = 2.98; P = 0.016). Multivariate Cox-regression further showed that LIC 125 μmol/g or more was associated with a decreased overall survival (HR = 2.24, P = 0.038), whereas ferritin or transfusion burden were not., Conclusions: SIO reflected by LIC is an independent negative prognostic factor for posttransplant outcome in patients with AML and MDS undergoing allo-SCT. Therefore, MRI-based LIC, and not interference-prone serum markers such as ferritin, should be preferred for pretransplant risk stratification and patient selection in future clinical trials., (©2012 AACR.)

Background: Recent technological advances have made whole-body MRI feasible within a reasonable time-frame. The clinical utility of whole-body MRI in patients with renal cell carcinoma has not been evaluated yet., Purpose: To compare the diagnostic accuracy of whole-body MRI and computed tomography (CT) in follow-up of patients with renal cell carcinoma., Material and Methods: In 28 patients with primary renal cell carcinoma a multislice CT scan of the thorax, abdomen, and pelvis, and a whole-body MRI were carried out as part of the postoperative follow-up. A combination of subsequent imaging studies and histology served as standard of reference., Results: MRI demonstrated a significantly better diagnostic accuracy regarding musculoskeletal metastases compared with CT (97.7% vs 82%, P<0.001). In contrast, CT was superior in the detection of pulmonary metastases (88.5% vs 71.9%, P<0.001). Both methods had similar diagnostic performance regarding lymph node metastases (CT, accuracy 82.4%; MRI, accuracy 83.4%, P=0.25). The concordance of both modalities regarding N and M stage was excellent (Cohen's kappa 1.00). In two patients cerebral metastases were revealed by MRI, which led to a change in therapy., Conclusion: At this stage, whole-body MRI cannot be considered an adequate replacement for CT in the follow-up of patients with renal cell carcinoma. Further significant improvement of lung MR protocols is necessary, as CT's sensitivity for pulmonary nodules is clearly superior. In contrast, the main advantage of whole-body MRI is its high diagnostic accuracy for musculoskeletal metastases.

A multicenter study has been employed to evaluate the diagnostic efficacy of magnetic resonance imaging (MRI) using the new liver-specific contrast agent gadoxetic acid (Gd-EOB-DTPA, Primovist), as opposed to contrast-enhanced biphasic spiral computed tomography (CT), in the diagnosis of focal liver lesions, compared with a standard of reference (SOR). One hundred and sixty-nine patients with hepatic lesions eligible for surgery underwent Gd-EOB-DTPA-enhanced MRI as well as CT within 6 weeks. Pathologic evaluation of the liver specimen combined with intraoperative ultrasound established the SOR. Data sets were evaluated on-site (14 investigators) and off-site (three independent blinded readers). Gd-EOB-DTPA was well tolerated. Three hundred and two lesions were detected in 131 patients valid for analysis by SOR. The frequency of correctly detected lesions was significantly higher on Gd-EOB-DTPA-enhanced MRI compared with CT in the clinical evaluation [10.44%; 95% confidence interval (CI): 4.88, 16.0]. In the blinded reading there was a trend towards Gd-EOB-DTPA-enhanced MRI, not reaching statistical significance (2.14%; 95% CI: -4.32, 8.6). However, the highest rate of correctly detected lesions with a diameter below 1 cm was achieved by Gd-EOB-DTPA-enhanced MRI. Differential diagnosis was superior for Gd-EOB-DTPA-enhanced MRI (82.1%) versus CT (71.0%). A change in surgical therapy was documented in 19 of 131 patients (14.5%) post Gd-EOB-DTPA-enhanced MRI. Gd-EOB-DTPA-enhanced MRI was superior in the diagnosis and therapeutic management of focal liver lesions compared with CT.

Objective: A study was undertaken to assess the clinical value of magnetic resonance (MR) imaging-guided interventions in women with a family history, but no personal history of breast cancer., Methods and Patients: Retrospective review was performed on 63 consecutive women who had a family history, but no personal history of breast cancer. A total of 97 lesions were referred for an MR-guided intervention. Standardized MR examinations (1.0 T, T1-weighted 3D FLASH, 0.15 mmolGd-DTPA/kg body weight, prone position) were performed using a dedicated system which allows vacuum assisted breast biopsy or wire localization., Results: Histologic findings in 87 procedures revealed 9 (10%) invasive carcinomas, 12 (14%) ductal carcinomas in situ, 2 atypical ductal hyperplasias (2.5%) and 2 atypical lobular hyperplasias (2.5%). Sixty-two (71%) benign histologic results are verified by an MR-guided intervention, retrospective correlation of imaging and histology and by subsequent follow-up. In ten lesions the indication dropped since the enhancing lesion was no longer visible. Absent enhancement was confirmed by short-term re-imaging of the noncompressed breast and by follow-up., Conclusion: Malignancy was found in 24%, high-risk lesions in 5% of successfully performed MR-guided biopsy procedures. A 57% of MR-detected malignancies were ductal carcinoma in situ. In 10% of the lesions the intervention was not performed, since no enhancing lesion could be reproduced at the date of anticipated intervention. Such problems may be avoided if the initial MRI is performed in the appropriate phase of the menstrual cycle and without hormonal replacement therapy.

A total of 50 unrelated marrow donors were examined by pelvic magnetic resonance imaging (MRI) to investigate the morphological sequelae of bone marrow harvesting (BMH). Signal increase in T2-weighted sequences and contrast media enhancement in T1 sequences at the operative sites were found as typical MRI morphology 4 weeks after harvest (group A, n=16), corresponding to edema, hyperemia and proliferative activity. Although tissue repair was completed in the majority of donors 1 year after BMH, about 36% of donors in group B (n=16) had abnormal findings. These included a persistence of the 'acute injury' signal pattern (2/16, 12%), and signal alterations due to fatty marrow conversion (4/16, 24%). The proportion of MRI abnormalities increased to over 70% in two-time donors (group C, n=11), which might indicate a cumulation of tissue damage after repetitive harvests. If donors had experienced prolonged discomfort after BMH (group D, n=7), MRI revealed pathological signals in 86%. In conclusion, the MRI morphology reflects the pathophysiological reactions after BMH, including inflammation and tissue repair. A further prospective evaluation in a larger number of donors is necessary to confirm these results and to identify the factors which influence the extent and duration of tissue damage.

For the case of pharyngeal carcinomas, the clinical value as well as the stability of several evaluation methods of MR tomographic perfusion measurement are compared. Eighteen patients suffering from histologically proven squamous cell carcinomas were investigated by MR tomography (1.5 T, 0.2 mmol/kg Gd-DTPA) prior to and during radiation therapy. Perfusion measurements were performed using a double-echo FLASH sequence. Parameters describing regional blood flow, blood volume, mean transit time, and interstitial concentration of contrast medium (CM) were calculated, applying seven different combinations of correction approaches (separating the shortening of T1 and T2*, arterial input function (AIF), and tumor shunts). Their correlations to MR independent tumor physiological parameters were analyzed (metabolic activity measurements using 18F-FDG-PET, polarographical pO2 measurement, tumor volume). Significant improvements of the correlation between perfusion-dependent and other tumor physiological parameters could be achieved by decoupling the shortening of T1 and T2* and by applying of the tumor shunt model. Deconvolution from the AIF deteriorated the correlation. Therefore, the elimination of the T1 shortening due to interstitial CM proves to be essential for MR perfusion measurements on contrast medium uptaking lesions. Depending on the measurement conditions (temporal resolution, signal-to-noise ratio), the consideration of the AIF can even make the results significantly worse by introducing additional measuring errors.

A study was undertaken to assess the diagnostic accuracy of contrast-enhanced MR mammography (MRM) of the contralateral breast in patients treated by breast-conserving therapy previously. A total of 119 patients underwent 145 standardized dynamic MR studies (1 T, T1-weighted 3D FLASH, 0.2 mmol Gd-DTPA/kg body weight). We retrospectively evaluated the results of conventional methods and MRM. A total of 11 contralateral carcinomas were present (detection rate 9%). The interval between treatment of the first primary and identification of contralateral malignancy was 9-80 months (mean 33 months). The MRM allowed detection of four otherwise occult malignancies. One of 11 cancer was missed on MRM due to benign appearance of enhancement. Compared with conventional methods MRM improved sensitivity (91 vs 64%) and specificity (90 vs 84%), respectively. This study suggests that additional MRM of the contralateral breast increases the diagnostic accuracy not only by enhancing the detection of second cancers but also by reducing false-positive results.

Purpose: To evaluate the safety and efficacy of gadoxetic acid disodium-enhanced magnetic resonance (MR) imaging for the detection of focal liver lesions, with results of histopathologic examination and/or intraoperative ultrasonography used as a standard of reference., Materials and Methods: One hundred sixty-nine patients who were known to have or suspected of having focal liver lesions and were scheduled for liver surgery were included in this study. Results in 131 patients could be included in the efficacy analysis. MR imaging was performed before and immediately and 20 minutes after bolus injection of 0.025 mmol/kg of the liver-specific hepatobiliary contrast agent gadoxetic acid. T1-weighted gradient-echo (with and without fat saturation and including dynamic data sets) and T2-weighted fast spin-echo/turbo spin-echo sequences were performed. All images were evaluated on site and by three independent and blinded off-site reviewers. Lesion matching based on the standard-of-reference results was performed. Differences in lesion detection with precontrast and with postcontrast MR images were assessed with the two-sided Wilcoxon signed rank test., Results: Gadoxetic acid was well tolerated. In the on-site review, the number of patients in whom all lesions were correctly matched increased from 89 of 129 patients at precontrast MR imaging to 103 of 129 patients at postcontrast MR imaging. In the off-site evaluation, the number of patients in whom all lesions were correctly matched and the corresponding sensitivity values increased from 72 (55.8%), 68 (52.7%), and 66 (51.2%) with the precontrast images to 88 (68.2%), 69 (53.5%), and 76 (58.9%) with the postcontrast images for readers 1, 2, and 3, respectively. Two of the three blinded readers showed a statistically significant difference in lesion detection between precontrast and postcontrast MR imaging (P <.001 and P =.008). A large number of additionally correctly detected and localized lesions were smaller than 1 cm., Conclusion: MR imaging with gadoxetic acid is safe and improves lesion detection and localization., (Copyright RSNA, 2004)

Aim: In MR perfusion measurements of contrast uptaking lesions, time intensity curves are hampered by T 1 shortening as well as by the change of T 2 * due to interstitial contrast material (CM). Using double echo sequences, the influence of T 1 can be mathematically eliminated. For correction of the T 2 * influence an empirical algorithm using time-intensity-curves exclusively measured in the suspected lesion is proposed., Methods: The interstitial CM concentration is assumed to be proportional to the change of the intensity for T E = 0 or to the change of the relaxation rate DeltaR 1 respectively. The intravascular CM concentration is estimated from DeltaR 2 *. It is adjusted to zero for a time point sufficiently late after the bolus injection by subtraction of the interstitial concentration. This method was applied to double echo FLASH measurements on 15 pharyngeal tumors., Results: The proposed correction transforms the time dependence of the estimated intravascular CM concentration into a plausible course., Conclusion: Double echo perfusion measurements can be corrected for the interstitial CM induced T 2 * shortening without additional measurements with proneness to errors. This does not necessarily improve the diagnostic value, since possibly "implied multivariate aspects" of uncorrected parameters (here: contrast uptake of the lesion is related to tumor neoangiogenesis as well) are eliminated.

Histologic work-up of just MR-detected breast lesions has become essential with increasing use of contrast-enhanced MR imaging. In the present article an overview is given about the different MR-guided breast interventions, performed since 1990. Presently, for reasons of costs and image quality closed magnets are most widely used. The following approaches have been described: MR-guided freehand localization in supine position, stereotaxic localization in supine position and most frequently used localization in the prone position by means of a compression device that immobilises the breast to prevent tissue shift during intervention. Only limited experience exists with interventions on open magnets. MR-guided wire localization is a well-established procedure. Recently, percutaneous vacuum biopsy of enhancing breast lesions has become possible under MR guidance. The new system allows accurate and safe access to lesions in any location of the breast and direct check-up of representative excision by visualisation of the cavity. Thus reliable histologic evaluation of lesions smaller than 10 mm is possible with this approach.

Different combinations of iron glycerophosphate (Fe) and gadolinium-diethylene triamine pentaacetic acid (DTPA) (Gd) were imaged with a three-dimensional (3D) gradient-recalled echo (GRE), a 2D GRE, and a HASTE sequence on a 1.5-T MR scanner. A combination of Fe and Gd results in a synergistic effect, which improves the signal gain for selective 3D imaging of the colon and simultaneously decreases the endoluminal signal on the HASTE and 2D GRE images for better visualization of water and Gd-enhanced structures in the gut wall.

Purpose: To evaluate gadobenate dimeglumine (Gd-BOPTA) for dynamic and delayed magnetic resonance (MR) imaging of focal liver lesions., Materials and Methods: In 126 of 214 patients, MR imaging was performed before Gd-BOPTA administration, immediately after bolus administration of a 0.05- mmol/kg dose of Gd-BOPTA, and 60-120 minutes after an additional intravenously infused 0.05-mmol/kg dose. In 88 patients, imaging was performed before and 60-120 minutes after a single, intravenously infused 0.1-mmol/kg dose. T1- and T2-weighted spin-echo and T1-weighted gradient-echo images were acquired. On-site and blinded off-site reviewers prospectively evaluated all images. Intraoperative ultrasonography, computed tomography (CT) during arterial portography, and/or CT with iodized oil served as the reference methods in 110 patients., Results: Significantly more lesions were detected on combined pre- and postcontrast images compared with on precontrast images alone (P <. 01). All reviewers reported a decreased mean size of the smallest detected lesion and improved lesion conspicuity on postcontrast images. All on-site reviewers and two off-site reviewers reported increased overall diagnostic confidence (P <.01). Additional lesion characterization information was provided on up to 109 (59%) of 184 delayed images and for up to 50 (42%) of 118 patients in whom dynamic images were assessed. Gd-BOPTA would have helped change the diagnosis in 99 (47%) of 209 cases and affected patient treatment in 408 (23%) of 209 cases., Conclusion: Gd-BOPTA increases liver lesion conspicuity and detectability and aids in the characterization of lesions.

Purpose: To assess liver and lesion enhancements by dynamic MR imaging after bolus injection of the hepatobiliary contrast agent gadolinium ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) in patients with liver metastases and to compare the effect of different doses., Material and Methods: A randomized double-blinded trial with doses of 12.5, 25 and 50 micromol/kg Gd-EOB-DTPA was performed in 35 patients with liver metastases. Liver enhancement, tumor enhancement and liver lesion contrast-to-noise (C/N) ratios were calculated from breath-hold gradient echo images (100/5/80 degrees) recorded precontrast and at different times up to 10 min postcontrast., Results: Normal liver showed a characteristic enhancement pattern, with a rapid enhancement in the first 45 s postcontrast and a slight but significant further increase up to 600 s. The initial enhancement in the lesions was also pronounced, but the enhancement was slightly decreased after 240 s postcontrast. At dose levels of 12.5 and 25 micromol/kg Gd-EOB-DTPA, C/N ratios significantly increased compared to baseline from 90 to 600 s. Postcontrast C/N-values obtained using 50 micromol/kg Gd-EOB-DTPA were not significantly increased, except for the examinations 480 s postcontrast., Conclusion: In liver metastases, C/N ratios obtained with doses of 12.5 and 25 micromol/kg Gd-EOB-DTPA were slightly superior to 50 micromol/kg Gd-EOB-DTPA. This finding is probably due to a more pronounced extracellular effect of the contrast medium at higher doses.

The paramagnetic extracellular Gd contrast media (Gd-CM) Magnevist, Dotarem, Omniscan, and ProHance are on the market, whereas Gadovist, Optimark, and MultiHance (also used as a hepatobiliary CM) are undergoing clinical trials (phase III). Among other indications, Gd-CM are applied in tumours, inflammation, vascular pathologies, and MR-angiography. The paramagnetic hepatobiliary CM Teslascan, Eovist and MultiHance are in clinical trials (phase II and III). They improve tumour detection and characterisation. The Mn-CM Teslascan is also suited for pancreatic imaging, the Gd-CM MultiHance for imaging of myocardial infarction and the brain, and the Gd-CM Eovist has been used in liver CT. The superparamagnetic reticuloendothelial CM Endorem is on the market whereas Resovist is undergoing phase-III trials. Both agents have the same indications as the hepatobiliary CM. Sinerem is another superparamagnetic CM. However, it acts as a blood pool agent and accumulates in lymph nodes (MR lymphography). Gastrointestinal CM are divided into paramagnetic, superparamagnetic and diamagnetic agents acting either as positive or negative CM. Some are on the market, but their clinical value is limited.

Purpose: To evaluate the safety, efficacy, and pharmacodynamic properties of a new superparamagnetic parenteral iron oxide contrast agent for magnetic resonance (MR) imaging., Materials and Methods: Thirty-six patients with liver lesions received a bolus injection of Resovist (SH U 555 A; Schering, Berlin, Germany) at a dose of 4, 8, or 16 micromol iron per kilogram body weight (micromol Fe/kg). Fast low-angle shot, spin-echo, and turbo gradient spin-echo MR images were obtained before and 10, 40, and 70 minutes after injection. Blood samples were obtained, vital signs were monitored, and adverse events were recorded. Lesion detection was assessed by two independent, blinded readers., Results: No drug-related adverse events occurred. Serum iron and ferritin levels were increased at all dose levels. Partial thromboplastin time increased and factor XI level decreased 4 hours after injection of 16 micromol Fe/kg. Lesion detection and diagnostic confidence were increased in patients who received 4 or 8 micromol Fe/kg, with no further increase with a 16-micromol dose., Conclusion: Resovist is safe and effective. The best MR imaging results were obtained 40 minutes after injection of 8 micromol Fe/kg.

Purpose: The purpose of this article was to assess the impact of intravenous (IV) anticholinergic hyoscine butylbromide in abdominal magnetic resonance (MR) imaging with oral magnetic particles (OMP) [ABDOS-CAN, Ferristene (USAN), Nycomed Imaging AS, Oslo, Norway]., Materials and Methods: In 31 patients with abdominal tumors, T1-weighted spin-echo (SE) images (SE 600/ 15; 1.5 T) were obtained without and with IV hyoscine butylbromide (20 mg) before and after administration of 800 ml of OMP. Two blinded readers assessed motion artifacts, bowel-wall visualization, and lesion delineation on the four sets of T1-weighted images. The two-tailed Wilcoxon paired sample test was used for statistical analysis (p < .05)., Results: Hyoscine butylbromide reduced motion artifacts and improved bowel-wall visualization on precontrast and OMP-enhanced images at a statistically significant level (p = 0.0006-0.037). The lowest degree of artifacts was recorded on OMP images with hyoscine butylbromide. OMP with hyoscine butylbromide significantly improved lesion delineation compared to studies without antiperistaltic drug before (p = 0.019) and after OMP administration (p = 0.01)., Conclusions: The authors conclude that the use of IV hyoscine butylbromide is recommended for OMP-enhanced abdominal MR imaging with T1-weighted SE pulse sequences at 1.5 T.

The aim of this study was to revisit anal anatomy, to explain surgical terminology in perianal complications of Crohn disease, and to show the MR imaging findings of perianal fistulas and abscesses. To this end more than 200 patients were studied using surface coils (Helmholtz; phased array) at 1.0 and 1.5 T. Transverse and coronal T1- and T2-weighted images were obtained. Parks' classification was used to describe perianal abscesses and fistulas. This pictorial essay shows the normal anal anatomy and pathologic findings such as subcutaneous, para-anal, ischiorectal, intersphincteric, and supralevatoric abscesses and fistulas. MR imaging with surface coils is well suited to showing the anal anatomy and to reliably describing perianal abscesses and fistulas according to surgical terminology.

Rationale and Objectives: In this phase III study, we evaluated the efficacy and safety of a negative contrast medium, ferristene (oral magnetic particles), among 277 patients undergoing magnetic resonance (MR) imaging of the abdomen., Methods: Enhanced (800 ml ferristene) MR images were compared with unenhanced MR images in an intraindividual-patient control design. Adverse events were recorded. The examinations were performed on 1.5-T MR systems (T1- and T2-weighted sequences)., Results: Ferristene increased the diagnostic information in 50.9% of the patients, particularly in those with abdominal masses, lymphoma, or pancreatic disease. Distribution of ferristene in the stomach, duodenum, jejunum, and ileum was complete or sufficient in 70.5-85% of the studies. In 64% of the patients, we were confident in the MR findings after the use of ferristene, and ferristene disclosed additional findings in 22% of the patients. The incidence of adverse events was 9.0%, but only 3.6% of all patients experienced ferristene-related adverse events (e.g., nausea, vomiting). Most events were mild or moderate in intensity., Conclusion: Ferristene was well tolerated, and for 50% of the patients it added useful diagnostic information.

ENDOREM (Guerbet, Sulzbach) is a superparamagnetic contrast agent for magnetic resonance imaging of the liver and spleen. The contrast agent consists of dextran-coated iron oxide particles with a size distribution between 120 and 180 nm and an iron concentration of 0.2 mol/l. Before ENDOREM received approval in Germany and other European countries, clinical trials were performed in Japan, the USA, and Europe. At a dose of 10 micromol Fe/kg (Japan, USA) and 15 micromol Fe/kg (Europe). ENDOREM was slowly infused in 100 ml of glucose 5% over approximately 30 min in 163 (Japan), 213 (USA), and 467 patients (Europe). The rate of side effects ranged between 6.1% (Japan) and 10.3% (Europe). The most frequent side effect was lower back pain. However, infusion was stopped or medication was necessary because of lower back pain in only very few cases. Transient increases of serum iron and ferritin and decreases of iron binding capacity occurred. No clinically relevant changes of heart rate and arterial blood pressure were observed. With the recommended biphasic infusion (2 ml/min over 10 min and 4 ml/min over 20 min) and at a dose of 15 micromol Fe/kg in 100 ml of glucose 5% ENDOREM is a well tolerated contrast agent

Following oral administration of a buffered gadopentetate-dimeglumine solution (Magnevist enteral, 1 mmol/l, 6-17 ml/kg) T1-, proton-density- and T2-weighted spin-echo images of abdominal and retroperitoneal lesions were acquired (0.5 T). Gadopentetate is a signal-enhancing, positive MR contrast agent, intraluminal air served as a model of a signal-free, negative agent. In 21 patients contrast/noise ratios of gadopentetate and air versus lesions and fat were compared quantitatively (t-test). In T1- and T2-weighted images contrast/noise ratios of gadopentetate versus lesions were significantly higher than those of air. In proton-density images there was no significant difference. In T1- and proton-density images contrast/noise ratios of air versus abdominal fat were significantly higher than those of gadopentetate, in T2-weighted images gadopentetate had a significantly higher contrast/noise ratio than air. Signal-enhancing positive contrast agents seem advantageous over signal-free negative enteral MR contrast agents.

AMI-25 was evaluated at 1.5 T as a superparamagnetic iron oxide contrast agent for the liver. Sixteen patients with up to five suspected focal liver lesions were examined with T1-, proton-density-, and T2-weighted spin-echo sequences before and after intravenous administration of AMI-25 (15 mumol/kg iron). The contrast-to-noise ratio (C/N) increased from 1.8 to 3.5 on 600/15 (TR msec/TE msec) images and from 1.7 to 7.9 on 2,500/15 images after AMI-25 administration (P < .01). C/N did not change significantly on 2,500/90 images. Two blinded readers counted the number of lesions visible on unenhanced and contrast-enhanced images, with the 32 sets of images of the 16 patients presented in random order. Both readers identified more lesions on AMI-25-enhanced images, but the difference was not statistically significant (P > .05). Two patients reported minor side effects (flushing, sensation of heat, lower back pain). On the basis of the results obtained in a limited number of patients, the authors conclude that at 1.5 T, AMI-25 does not significantly improve the detection of focal liver lesions on conventional spin-echo images.

Superparamagnetic iron oxide particles (AMI-25) were evaluated as a liver contrast agent in high-field MR imaging (1.5 T). 16 patients with up to 5 presumed focal liver lesions (liver metastases n = 8, HCC n = 5, Klatskin tumours n = 2, FNH n = 1) received 15 mumol Fe/kg BW intravenously and were examined via standard T1- and T2-weighted spin-echo sequences. Quantitative image analysis showed a post-contrast increase of the contrast-to-noise ratio (C/N) from 1.6 to 7.4 on SE 2,500/15 images (p < .05). However, C/N was in the same range on plain SE 2,500/90 scans. Blind evaluation by two independent readers revealed that AMI-25-enhanced images did not provide a significantly increased number of lesions. Two patients reported minor, self-limited side-effects (flush, back pain). We conclude that in contrast to reports at mid-field MR imagers, the use of AMI-25 at 1.5 T does not significantly improve the detection of focal liver lesions on conventional SE images.

Magnetic resonance imaging (MRI) was undertaken in a prospective study of 34 consecutive patients (21 women, 13 men; median age 31 [18-53] years) suspected of having active perianal Crohn's disease. The results of the investigation were compared with those obtained by independent observers on proctological and intraoperative examination (n = 31). A total of 58 fistulas and 21 abscesses were noted intraoperatively, 47 fistulas and all 21 abscesses by MRI, and 40 fistulas and 13 abscesses proctologically. The proctological examination proved to be more sensitive in demonstrating short subcutaneous or anovaginal fistulas (three of four subcutaneous and two of five anovaginal fistulas were not shown by MRI). Intersphincteric, ischiorectal and supralevator involvement was shown better by MRI. These results indicate that in perianal Crohn's disease MRI is a useful addition to proctological examination.

The value of selective imaging of fat and water compared with proton density, T1- and T2- weighted MR sequences was studied in the course of 32 examinations on 22 primary bone tumours in various parts of the body. Fat selective images showed practically signal free areas for osteogenic tumours which could be distinguished from surrounding fat containing soft tissues. Water selective images improved definition of the tumour margin from oedema in the bone marrow. Chemical shift artefacts are avoided by these methods and therefore fat and water selective images provide better spatial resolution for identical pixel sizes.

Twenty patients with malignant liver lesions underwent magnetic resonance (MR) imaging with manganese (II) DPDP [N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate)] to evaluate the safety and efficacy of the contrast agent. In two groups of 10 patients each, 5 mumol/kg Mn-DPDP was administered intravenously (3 mL/min) at a concentration of either 50 or 10 mumol/mL. T1- and T2-weighted images were obtained with a 1.5-T imager. Six patients reported a total of eight instances of side effects (flush, feeling of warmth, metallic taste) of which seven occurred at the 50 mumol/mL concentration. A significant decrease in alkaline phosphatase levels 2 hours after injection was recorded. On T1-weighted images, the 10 mumol/mL formulation yielded significantly greater increases in contrast-to-noise ratio (79.8%-137.5%) than the 50 mumol/mL formulation (46.2%-86.6%). In a blinded reader study of 10 patients with one to five lesions each, no lesion was missed on Mn-DPDP--enhanced T1-weighted images; however, four false-positive foci were identified. The authors conclude that slow administration of 5 mumol/kg Mn-DPDP at a concentration of 10 mumol/mL is safe and efficient enough to proceed to further clinical trials.

The diagnostic value of magnetic resonance imaging (MRI) in gastroenterology has not been definitely defined. In focal liver lesions MRI has a high sensitivity and aids in the differential diagnosis. In pathologies of the gall bladder and the pancreas, MRI currently has no clinical relevance. MRI diagnosis of pelvic fistulas and abscesses in chronic inflammatory bowel disease is both sensitive and specific. MRI is superior to CT in detecting and differentiating recurrent rectal cancer.

Purpose: To investigate the efficacy of 0.025, 0.05 and 0.1 mmol/kg gadopentetate dimeglumine in MR imaging of patients with intracranial tumors at mid and high field strength., Methods: In 88 patients, an open-label phase III multicenter dose-finding study was performed at 0.5, 1.0, and 1.5 T MR units. Before and after (5, 15, 25 minutes) intravenous administration of gadopentetate dimeglumine, imaging was performed with T1-weighted spin-echo sequences., Results: With 0.1 mmol/kg yielding the highest values, tumor enhancement and numerical tumor/brain contrast showed dose-dependent 5-minute postcontrast values (P less than 0.05). Compared to 5-minute postcontrast values, there was no significant change at 15 and 25 minutes. Although the lowest values of enhancement were found at 0.5 T, differences in enhancement among the field strengths were not statistically significant. The numerical data were confirmed by visual assessment of tumor/brain contrast. Eighty to 90% of cases had diagnostically valuable enhancement at 0.1 mmol/kg, 50% at 0.05 mmol/kg, and 10% at 0.025 mmol/kg (P less than 0.05). There were no adverse events., Conclusion: Our results confirm that 0.1 mmol/kg gadopentetate dimeglumine is more effective at enhancing intracranial tumors than lower doses at mid and high field MR units.

At present, the value and limitations of magnetic resonance imaging (MRI) as a diagnostic modality in gastroenterology cannot be conclusively determined. MRI has a high sensitivity in the detection of focal liver lesions. The signal intensity of focal liver lesions on plain and contrast-enhanced T1-weighted images and on plain T2-weighted scans narrows the differential diagnosis in many cases. Imaging of the gallbladder and pancreas presently is no indication for MRI. The high sensitivity of MRI in the detection of fistulae and abscesses in Crohn's disease and the differentiation from fibrosis represents an advantage over other modalities in imaging of inflammatory bowel disease. MRI is superior to CT in differentiating recurrent rectal cancer from fibrosis. Further development of MRI and the use of contrast media for both oral and intravenous administration may offer new perspectives of MRI in the diagnosis of diseases in gastroenterology.

Safety and efficacy of gadopentetate-dimeglumine (Gd-DTPA) as a MR bowel contrast agent were determined in 133 patients with CT-proved abdominal and retroperitoneal mass lesions using a buffered formulation (1 mmol/l Gd-DTPA, 15 g/l mannitol, 25 mmol/l sodium-citrate, 6-17 ml/kg). Short-lived gastrointestinal side effects were noted in 32% of patients. Gd-DTPA provided uniform, hyperintense bowel labelling and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with pre- and postcontrast images lesion delineation was improved in 62%. In 55 studies with postcontrast images only, Gd-DTPA proved useful in 65%. In 105 of 109 cases IV injection of scopolamine or glucagon eliminated image artifacts arising from peristalsis of opacified bowel. The authors conclude that Gd-DTPA is a safe and effective MR bowel contrast agent.

The value of magnetic resonance imaging (MRI) in the gastrointestinal tract has not yet been determined. In neoplastic disease, MRI has a high sensitivity in the detection of liver metastases secondary to colorectal cancer. MRI is superior to CT in differentiating recurrent rectal cancer from fibrosis. The high sensitivity of MRI in the detection of fistulae in Crohn's disease and the differentiation from fibrosis represents an advantage over other modalities in imaging of inflammatory bowel disease. Further development of MRI and the use of contrast media for both oral and intravenous administration may offer new perspectives of MRI in diseases of the gastrointestinal tract.

To determine the safety and efficacy of gadopentetate dimeglumine as a bowel contrast agent, magnetic resonance (MR) imaging (0.5 T) was performed with a formulation of gadopentetate dimeglumine (1.0 mmol/L of gadopentetate dimeglumine, 15 g/L of mannitol, 6-17 mL/kg) in 133 patients with intraabdominal mass lesions. Mostly short-lived gastrointestinal side effects were noted in 32% of patients. Gadopentetate dimeglumine provided uniform hyperintense marking of the bowel and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with images obtained both before and after administration of contrast material, post-contrast improvement of lesion delineation was found in 62%. Among 55 patients with only postcontrast images, gadopentetate dimeglumine proved useful in 65%. Intravenous injection of scopolamine or glucagon effectively eliminated "ghost" images of the opacified bowel in 105 of 109 cases. The authors conclude that gadopentetate dimeglumine is a safe and effective bowel contrast agent for MR imaging.

Contrast media in magnetic resonance imaging (MRI) of the abdomen and pelvis are applied for various purposes; different substances and forms of application must be distinguished. Oral contrast agents are primarily used to enhance the discrimination of the intestine from the other organs and from pathological lesions. Clinical studies of i.v. contrast agents focus on two substances: gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and superparamagnetic iron oxide. Whereas dynamic Gd-DTPA-enhanced MRI improves the differential diagnosis of focal hepatic lesions, iron oxide is a promising agent for increasing the sensitivity of MRI in the detection of hepatic and splenic tumors. Dynamic Gd-DTPA-enhanced MRI of the kidney allows functional assessment of this organ; good demarcation of kidney tumors is only achieved during the early phase of a dynamic examination. In the assessment of adrenal lesions, dynamic Gd-DTPA-enhanced MRI permits better differentiation of adenoma from malignancy. Intravenous Gd-DTPA also appears to be useful in the staging of urinary bladder tumors to distinguish between superficial and infiltrating tumors. Although offering no major diagnostic advantage in the staging of cervical carcinomas, Gd-DTPA-enhanced MRI improves the discrimination of necrotic tumor portions of endometrial carcinoma and allows good differentiation of this lesion from fluid retained in the uterine cavity. Studies of new contrast agents for MRI of the abdomen, which have so far only been investigated in animal experiments, focus on liver imaging. These substance include hepatobiliary agents, Gd-DTPA-containing liposomes, and paramagnetic macromolecules.

One hundred and fifty gadolinium(Gd)-DTPA studies in patients with intracranial tumors were performed. In meningiomas (n = 37) Gd-DTPA is useful to delineate isointense tumors. In acoustic neuromas (n = 16) Gd-DTPA helps to identify intracanalicular tumor tissue. In pituitary adenomas (n = 16) para- or suprasellar tumor extension can be better appreciated after Gd-DTPA injection. In glioblastomas (n = 23) Gd-DTPA provides data on differential diagnosis through the characteristic shape of enhancement. In a variety of tumor types the high contrast between enhancing tumor tissue and adjacent structures facilitates therapy planning. Fast imaging sequences now allow for dynamic Gd-DTPA studies. The time-course of enhancement may increase specificity of magnetic resonance imaging.

A multislice gradient echo sequence (FLASH) was compared with a conventional spin-echo (SE) technique with regard to its value for contrast enhanced MR diagnosis. In 28 patients with cerebral tumours, SE images (SE 400/30; four images/3.4 minutes) and FLASH images (FLASH 315/14; 15 images/1.4 minutes) were obtained before and after gadolinium DTPA. After gadolinium-DTPA results were comparable for both techniques with respect to contrast enhancement, tumor contrast and delineation. Because of the higher efficiency of the FLASH 315/14 technique, this sequence is the method of choice for contrast enhanced cerebral MR imaging.

Beagle dogs were investigated by MRI (Siemens Magnetom, 0.35 T) after oral administration of aqueous solutions of Gd-DTPA (n = 4), ferric ammonium citrate (n = 1), and magnetite dextran (n = 2). High signal intensity of the GI-tract versus adjacent structures was obtained with Gd-DTPA and ferric ammonium citrate. Magnetite showed negative contrast versus adjacent structures. However, magnetite displayed lower contrast relative to liver, muscle and gut wall compared to Gd-DTPA and ferric ammonium citrate. In relatively T2-weighted sequences labeling of poorly filled bowel loops was significantly better with Gd-DTPA and ferric ammonium citrate. For GI-tract contrast enhancement we conclude that positive contrast media are of higher diagnostic value compared to negative contrast agents.

In 36 patients with intracranial tumors, gadolinium (Gd)-DTPA-enhanced SE 400/35, SE 800/35 and IR 1500/400/35 sequences were intraindividually compared. Contrast enhancement usually was shown to better advantage with the IR sequence. Post-contrast SI of tumor tissue was isointense with white matter on IR images in many cases whereas SE sequences displayed enhancing tumor with high contrast versus brain. Post-contrast tumor delineation, therefore, was better with the SE sequences especially in white matter lesions without perifocal edema. The SE 400/35 sequence which allows for contrast-enhanced MRI within a relatively short time is suggested for Gd-DTPA studies of brain tumors.

80 patients with tumorous or inflammatory abdominal diseases were investigated with the paramagnetic MRT contrast medium Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l mannitol, 6-16 ml per kg body weight) at 0.5 Tesla with T1-, proton density and T2-weighted SE- and gradient-echo sequences. 53 patients were investigated also before the contrast medium was given. Gd-DTPA showed hyperintense labelling of the intestinal loops that was detectable with all excitation sequences and was constant over all phases of the passage. In 35 of the 53 patients investigated before and after application of Gd-DTPA lesions were better imaged while diagnostic improvements, especially for smaller lesions, were achieved in 5 of 80 patients. One third of the patients reported slight meteorism and diarrhoea after the mannitol-containing suspension.