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Beta-2-microglobulin is a serum maker of tumor burden in hematologic malignancies. We aimed to correlate serum β2-microglobulin levels in patients with multiple myeloma (MM) to tumor mass determined by whole-body MRI.We retrospectively included patients with newly diagnosed, untreated MM who underwent whole-body MRI at our institution between 2003 and 2011. Patients with a glomerular filtration rate of less than 60 mL/min were excluded from analysis because β2-microglobulin levels are increased in renal failure. Thirty patients could be included. Whole-body MRI examinations (T1-weighted turbo spin-echo and STIR sequences) were assessed by two musculoskeletal radiologists in consensus for focal lesions and the presence of diffuse myeloma infiltration. The presence of diffuse infiltration was confirmed by histology as the reference standard. MM was staged according to the Durie and Salmon PLUS staging system.According to whole-body MRI findings, MM was classified as Durie and Salmon PLUS stage I (low grade) in 13 patients, stage II (intermediate grade) in six patients, and stage III (high grade) in 11 patients. As we expected, most patients with stage I disease (12/13) had normal β2-microglobulin levels (≤ 3 mg/L). Higher β2-microglobulin values were associated with a higher stage of disease (p0.05). However, five of six patients with stage II MM and five of 11 patients with stage III MM showed normal β2-microglobulin levels. Thus, 10 of 17 patients (58.8%) with substantial infiltration in the bone marrow showed false-negative β2-microglobulin levels.Serum β2-microglobulin levels correlate with tumor stage in MM. However, it may be misleading as a marker of tumor load in a subset of patients with substantial myeloma infiltration in the bone marrow. Whole-body MRI may display the full tumor load and correctly show the extension of myeloma infiltrates.

The purpose of our study was to determine the optimum combination of b values for calculating the apparent diffusion coefficient (ADC) using a diffusion-weighted (DW) single-shot turbo spin-echo (TSE) sequence in the differentiation between acute benign and malignant vertebral body fractures.Twenty-six patients with osteoporotic (mean age, 69 years; range, 31.5-86.2 years) and 20 patients with malignant vertebral fractures (mean age, 63.4 years; range, 24.7-86.4 years) were studied. T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. A DW single-shot TSE sequence at different b values (100, 250, 400, and 600 s/mm(2)) was applied. On the DW images for each evaluated fracture, an ROI was manually adapted to the area of hyperintense signal intensity on STIR-hypointense signal on T1-weighted images. For each ROI, nine different combinations of two, three, and four b values were used to calculate the ADC using a least-squares algorithm. The Student t test and Mann-Whitney U test were used to determine significant differences between benign and malignant fractures. An ROC analysis and the Youden index were used to determine cutoff values for assessment of the highest sensitivity and specificity for the different ADC values. The positive (PPV) and negative predictive values (NPV) were also determined.All calculated ADCs (except the combination of b = 400 s/mm(2) and b = 600 s/mm(2)) showed statistically significant differences between benign and malignant vertebral body fractures, with benign fractures having higher ADCs than malignant ones. The use of higher b values resulted in lower ADCs than those calculated with low b values. The highest AUC (0.85) showed the ADCs calculated with b = 100 and 400 s/mm(2), and the second highest AUC (0.829) showed the ADCs calculated with b = 100, 250, and 400 s/mm(2). The Youden index with equal weight given to sensitivity and specificity suggests use of an ADC calculated with b = 100, 250, and 400 s/mm(2) (cutoff ADC,1.7 × 10(-3) mm(2)/s) to best diagnose malignancy (sensitivity, 85%; specificity, 84.6%; PPV, 81.0%; NPV, 88.0%).ADCs calculated with a combination of low to intermediate b values (b = 100, 250, and 400 s/mm(2)) provide the best diagnostic performance of a DW single-shot TSE sequence to differentiate acute benign and malignant vertebral body fractures.

The objective of our study was to compare the diagnostic value of qualitative diffusion-weighted imaging (DWI), quantitative DWI, and chemical-shift imaging in a single prospective cohort of patients with acute osteoporotic and malignant vertebral fractures.The study group was composed of patients with 26 osteoporotic vertebral fractures (18 women, eight men; mean age, 69 years; age range, 31 years 6 months to 86 years 2 months) and 20 malignant vertebral fractures (nine women, 11 men; mean age, 63.4 years; age range, 24 years 8 months to 86 years 4 months). T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. A DW reverse fast imaging with steady-state free precession (PSIF) sequence at different delta values was evaluated qualitatively. A DW echo-planar imaging (EPI) sequence and a DW single-shot turbo spin-echo (TSE) sequence at different b values were evaluated qualitatively and quantitatively using the apparent diffusion coefficient. Opposed-phase sequences were used to assess signal intensity qualitatively. The signal loss between in- and opposed-phase images was determined quantitatively. Two-tailed Fisher exact test, Mann-Whitney test, and receiver operating characteristic analysis were performed. Sensitivities, specificities, and accuracies were determined.Qualitative DW-PSIF imaging (delta = 3 ms) showed the best performance for distinguishing between benign and malignant fractures (sensitivity, 100%; specificity, 88.5%; accuracy, 93.5%). Qualitative DW-EPI (b = 50 s/mm(2) [p = 1.00]; b = 250 s/mm(2) [p = 0.50]) and DW single-shot TSE imaging (b = 100 s/mm(2) [p = 1.00]; b = 250 s/mm(2) [p = 0.18]; b = 400 s/mm(2) [p = 0.18]; b = 600 s/mm(2) [p = 0.39]) did not indicate significant differences between benign and malignant fractures. DW-EPI using a b value of 500 s/mm(2) (p = 0.01) indicated significant differences between benign and malignant vertebral fractures. Quantitative DW-EPI (p = 0.09) and qualitative opposed-phase imaging (p = 0.06) did not exhibit significant differences, quantitative DW single-shot TSE imaging (p = 0.002) and quantitative chemical-shift imaging (p = 0.01) showed significant differences between benign and malignant fractures.The DW-PSIF sequence (delta = 3 ms) had the highest accuracy in differentiating benign from malignant vertebral fractures. Quantitative chemical-shift imaging and quantitative DW single-shot TSE imaging had a lower accuracy than DW-PSIF imaging because of a large overlap. Qualitative assessment of opposed-phase, DW-EPI, and DW single-shot TSE sequences and quantitative assessment of the DW-EPI sequence were not suitable for distinguishing between benign and malignant vertebral fractures.

In patients with suspected but yet not localized neuroendocrine tumors (NETs), early diagnosis or reliable exclusion is crucial for optimal individual prognosis and therapy. Despite recourse to several imaging modalities, the definite diagnosis of NET can be challenging. Therefore, we tested (68)Ga-DOTATATE PET/CT as a tool for improved diagnosis in a cohort of patients with suspected, nonlocalized NET.(68)Ga-DOTATATE PET/CT recordings were obtained in 104 consecutive patients meeting at least one of the following criteria: clinical suspicion of NET (n = 70), elevated blood levels of tumor markers (n = 49), and image-based suspicion of NET (n = 53). The presence of NET was validated by histopathology (n = 49) or clinical follow-up of 107 ± 59 wk (n = 55).In 36 of 104 patients (35%), NET was histologically verified, most frequently located in the small bowel (10/36), pancreas (8/36), lung (5/36), and stomach (2/36). Twelve patients had tumors of nonneuroendocrine origin, and 7 patients had benign tumors. (68)Ga-DOTATATE PET/CT identified NET in 29 of the 36 cases and excluded the presence of a NET in 61 of the 68 non-NET patients, indicating a sensitivity of 81% and specificity of 90%. The PET/CT gave a false-positive result in 7 patients and a false-negative in another 7 patients, indicating positive and negative predictive values of 81% and 90%, respectively, and an accuracy of 87%. Chromogranin A levels were significantly higher in both PET-positive patients (1,841 vs. 342 ng/mL; P0.05) and patients with verified NET (2,214 vs. 524 ng/mL; P0.05).In patients with suspected NETs due to clinical symptoms, elevated levels of tumor markers, or indeterminate tumors suggestive of NET, (68)Ga-DOTATATE PET/CT is highly accurate, thus supporting its use in clinical routine diagnostics.

Staging/Follow-up beim kolorektalen Karzinom wird normalerweise mit multimodalen Bildgebungsverfahren durchgefuhrt. Diese konnen jedoch zeitintensiv sein und bergen die Gefahr einer untersucherabhangigen Befundvarianz. Alternativ bietet die Ganzkorper-MRT eine onkologische Bildgebung mit einem systemischen Ansatz. Sonographie, dedizierte MRT, Mehrzeilencomputertomographie (MSCT) oder Positronenemissionstomographie/CT (PET/CT). Hochauflosende Ganzkorper-MRT mit fokussierten Untersuchungen einzelner Organe, z. B. Becken und Bauchorgane, Lunge, Gehirn oder Skelettsystem mit unterschiedlichen Sequenztechniken und Kontrastierungen. Kolorektale Rezidiverkennung mit der Ganzkorper-MRT: 83% Genauigkeit (Lymphknotenmetastasen 80%, Fernmetastasen 86%). Potenzielle Kostenreduktion durch Verringerung der Untersuchungszeiten und Personalkosten. Strahlungsfreie Alternative zu klassischen Stufenalgorithmen beim Staging/Follow-up des kolorektalen Karzinoms

The purpose of this study is to correlate the presence of intradiscal vacuum phenomenon on CT to that of intradiscal fluid on MRI.In a prospective study, 20 patients with lumbar vacuum phenomenon on CT underwent two MRI examinations. One was performed after mobilization, and the other was performed after 6 hours of bed rest. T2-weighted turbo-spin echo (TSE), STIR, T1-weighted TSE, and four consecutive T2-weighted TSE sequences were performed on a 1.5-T scanner. Ninety-five discal segments were assessed for the presence of intradiscal fluid or hyperintense signal on the T2-weighted MRI examinations and were correlated with the presence of vacuum phenomenon on CT, degenerative endplate abnormalities on CT, and edema on MRI.Sixty-nine of 95 discal segments (72.6%) showed vacuum phenomenon on CT. Sixteen of those 69 discal segments (23.1%) showed intradiscal fluid (n = 12) or hyperintense signal (n = 4) on MRI examinations performed after mobilization. Forty-one of 69 discal segments (59.4%) with vacuum phenomenon showed intradiscal fluid (n = 29) or hyperintense signal (n = 12) on MRI examinations performed after bed rest. Seventeen segments showed only fluid after bed rest. Nine segments showed more fluid after bed rest than after mobilization. Three segments showed an unchanged amount of fluid. There was a significant correlation between the presence of intradiscal fluid and the amount of bone marrow edema on MRI and the presence of degenerative endplate abnormalities on CT, respectively.The replacement of intradiscal vacuum phenomenon by intradiscal fluid is a time- and position-dependent dynamic process and is related to Modic type 1 degenerative disk disease and degenerative endplate changes.

To evaluate safety, efficacy, and symptom-control of radioembolization in patients with unresectable liver metastases from neuroendocrine tumors (NETLMs).Forty-two patients (mean age of 62 years) with treatment-refractory NETLMs underwent radioembolization using yttrium-90 ((90)Y) resin microspheres. Posttreatment tumor response was assessed by cross-sectional imaging using the Response Evaluation Criteria in Solid Tumors (RECIST) and tumor-marker levels. Laboratory and clinical toxicities and clinical symptoms were monitored.The median activity delivered was 1.63 GBq (range 0.63-2.36). Imaging follow-up using RECIST at 3-month follow-up demonstrated partial response, stable disease, and progressive disease in 22.5, 75.0, and 2.5% of patients, respectively. In 97.5% of patients, the liver lesions appeared hypovascular or partially necrotic. The mean follow-up was 16.2 months with 40 patients (95.2%) remaining alive. The median decrease in tumor-marker levels at 3 months was 54.8% (chromogranin A) and 37.3% (serotonin), respectively. There were no acute or delayed toxicities greater than grade 2 according to Common Terminology Criteria for Adverse Events [CTCAE (v3.0)]. No radiation-induced liver disease was noted. Improvement of clinical symptoms 3 months after treatment was observed in 36 of 38 symptomatic patients.Radioembolization with (90)Y-microspheres is a safe and effective treatment option in patients with otherwise treatment-refractory NETLMs. Antitumoral effect is supported by good local tumor control, decreased tumor-marker levels, and improved clinical symptoms. Further investigation is warranted to define the role of radioembolization in the treatment paradigm for NETLMs.

In clinical trials with yttrium-90-resin-microspheres for the management of colorectal cancer liver metastases, it was observed that radioembolization might result in splenomegaly and an increase in portal vein size. Subclinical hepatitis in normal liver tissue as well as the effects of radioembolization and prior chemotherapy are suspected to be responsible for this phenomenon. The purpose of this study was to quantify the changes in liver and spleen volume and portal vein diameter after radioembolization. Twenty-seven patients with liver-dominant metastatic disease from breast cancer who had not responded to chemotherapy or had to abandon chemotherapy because of its toxic effects were evaluated. Changes in liver and spleen volume and portal vein diameter as well as liver tumor volume and diameter were quantified using computed tomography scans. Radioembolization was associated with a significant mean decrease in the whole liver volume of 10.2% (median 16.7%; P = 0.0024), mainly caused by a reduction in the right lobe volume (mean 16.0%; P

Purpose: To evaluate the potential of quantitative dynamic contrast-enhanced MRI (DCE-MRI) in vertebral bone marrow (vBM) of patients with acute osteoporotic vertebral compression fractures. Materials and Methods: Twenty-six patients with acute osteoporotic fractures (16 female, 10 male, median age 72, range 48–89) and 10 subjects without known history of osteoporosis (6 female, 4 male, median 65, range 31–77) were examined 2D-DCE-MRI. Region of interest (ROI) data in fractured (n = 26) and normal-appearing vertebrae (n = 271) were analyzed with a two-compartment tracer-kinetic-model, providing estimates of at least three independent parameters: plasma flow (PF), plasma volume (PV), and extraction flow (EF). Parameters were correlated with dual x-ray absorptiometry (DXA) (n = 15) and quantitative computed tomography (QCT) densitometry (n = 10). Results: Mean PF was significantly higher in fractures than in normal-appearing vertebrae (69.37 vs. 11.72 mL/100 mL/min). Similarly, mean PV and EF differed significantly. Mean PF was significantly decreased in normal-appearing vBM osteoporotic patients compared to the control group. Mean PF and PV were significantly decreased in lumbar compared to thoracic vertebrae. PV showed a significant correlation with QCT. Conclusion: Perfusion parameters were decreased significantly in normal-appearing vBM of patients. Furthermore, significant perfusion alterations were observed in acute osteoporotic vertebral fractures compared to normal-appearing vertebrae. J. Magn. Reson. Imaging 2011;33:676–683. © 2011 Wiley-Liss, Inc.

Patients with multiple myeloma are often treated surgically as though they have bone metastases. Due to major differences in oncological therapy and comparatively long survival times these patients should be considered separately. Seventy-five multiple myeloma patients were treated surgically (83 interventions) for skeletal complications of the disease. Location and dissemination, symptoms, method of surgery, complications, recurrence and survival time were evaluated retrospectively. Most of the lesions were in the axial skeleton or the proximal extremities apart from one distal lesion of the fibula, and most surgery was performed in the spine (35 patients). The mean follow-up of patients was 5.4 years (range 1–25 years). Survival proved to be very favourable (37% at five years). Patients with a single bone lesion, a negative bone marrow biopsy, no paraproteinaemia in serum or a Salmon-Durie-stage I had a better survival probability. Surgical treatment in patients with multiple myeloma was mostly limited to a palliative approach but survival time was better (37% at five years) than in patients with metastatic bone disease which has to be considered in their surgical treatment.

We aimed to evaluate (68)Ga-DOTATATE PET/CT for the early prediction of time to progression and clinical outcome after a first cycle of peptide receptor radionuclide treatment (PRRT) in a cohort of patients with well-differentiated neuroendocrine tumors.Thirty-three consecutive patients (22 men and 11 women; mean age +/- SD, 57.8 +/- 12.1 y) were investigated at baseline and again 3 mo after initiation of the first cycle of PRRT. (68)Ga-DOTATATE receptor expression was assessed using 2 measures of standardized uptake value (SUV): maximum SUV (SUV(max)) and tumor-to-spleen SUV ratio (SUV(T/S)). Percentage change in SUV scores after PRRT relative to baseline (DeltaSUV) was calculated. After completing 1-3 cycles of PRRT, patients entered the follow-up study, for estimation of time to progression. According to the Response Evaluation Criteria in Solid Tumors, progression was defined on the basis of contrast-enhanced CT. Clinical symptoms, as well as the tumor markers chromogranin A and neuron-specific enolase, were also recorded during regular follow-up visits.The 23 of 31 patients with decreased SUV(T/S) after the first PRRT cycle had longer progression-free survival than did the 8 of 31 patients with stable or increased scores (median survival not reached vs. 6 mo, P = 0.002). For the 18 of 33 patients showing a reduction in SUV(max), there was no significant difference in progression-free survival (median survival not reached vs. 14 mo, P = 0.22). Multivariate regression analysis identified SUV(T/S) as the only independent predictor for tumor progression during follow-up. In the 17 of 33 patients with clinical symptoms before PRRT, DeltaSUV(T/S) correlated with clinical improvement (r = 0.52, P0.05), whereas DeltaSUV(max) did not (r = 0.42, P = 0.10). Changes in the tumor markers (chromogranin A and neuron-specific enolase) did not predict DeltaSUV scores, clinical improvement, or time to progression.Decreased (68)Ga-DOTATATE uptake in tumors after the first cycle of PRRT predicted time to progression and correlated with an improvement in clinical symptoms among patients with well-differentiated neuroendocrine tumors; DeltaSUV(T/S) was superior to DeltaSUV(max) for prediction of outcome.

Dynamic contrast-enhanced MRI data in vertebral bone marrow (vBM) are currently analyzed with descriptive indices. The purpose of this study was to develop and evaluate a quantitative approach, considering the tissue composition of vBM. Therefore, a measurement of the water fraction, fwat, and the precontrast relaxation times, T10 wat, T10 fat, was added to the routine protocol. Signal analysis was generalized by allowing for an arbitrary fraction of fat. Plasma flow, plasma volume, extraction flow, and interstitial volume were determined from dynamic contrast-enhanced-MRI data. Simulations were used to determine the sensitivity to the precontrast values and to retrospectively verify the choice of the sequence parameters. Measurements were performed in healthy vertebral bodies (n = 30) and lesions of 15 patients with vertebral fractures. Extraction flow (milliliters per 100 mL/min) provided the strongest normal/abnormal separation: mean (standard deviation) was 0.3 (0.8) in healthy vBM and 6(4) in the fractures. Neglecting the fat component and the approximated signal analysis using relative signal enhancement produced significant differences. We conclude that correcting for the fat component in the signal and parametrization by tracer-kinetic analysis is necessary to avoid misinterpretation and/or systematic errors. The quantitative analysis is equally well suited as a descriptive parameter for the differentiation between normal and abnormal vertebral bone marrow. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.

Vergleich der immunhistochemischen Expression des Somatostatinrezeptor- (SSTR-)Subtyps 2 mit der quantitativen 68Ga-DOTATATE-PET bei neuroendokrinen Tumoren (NET). Bei 27 Patienten mit metastasierten NET wurde die immunhistochemische Expression des SSTR-Typs 2 anhand einer Graduierung (0–3) bestimmt. Zusatzlich konnte bei 25/27 Patienten der Proliferationsindex Ki-67 ermittelt werden. Damit verglichen wurde die Speicherung von 68Ga-DOTATATE anhand des SUVmax (SUV „standardized uptake value“). NET ohne SSTR-Expression wiesen einen signifikant (p

The advent of whole-body MRI (WB-MRI) has introduced a systemic approach to oncologic imaging compared to established sequential, multi-modal diagnostic algorithms. Hardware innovations, such as whole-body scanners at 1.5 Tesla and also recently 3 Tesla, combined with acquisition acceleration techniques, have made WB-MRI clinically feasible. With this method dedicated assessment of individual organs with various soft tissue contrast, high spatial resolution and contrast media dynamics can be combined with whole-body anatomic coverage.PET/CT has established itself as a powerful modality in the staging of patients suffering from malignant tumors. In addition to the morphologic information provided by the CT component of this hybrid modality, the PET component contributes invaluable metabolic information, which greatly enhances accuracy in the assessment of lymphatic spread and viability of tumor tissue. Whole-body MR diffusion imaging is a novel and promising technique which may contribute to superior sensitivity in the detection of tumor manifestations. In the assessment of distant metastatic spread WB-MRI is highly sensitive and has advantages over PET/CT, especially in those tumors frequently spreading to the liver, bone or brain. WB-MRI is also very attractive as a radiation-free alternative for imaging of pediatric tumor patients in whom multiple follow-up examinations may be required.WB-MRI allows for precise assessment of the bone marrow and has been proven to be highly accurate for the staging of hematologic diseases, such as multiple myeloma. In this article recent developments and applications of WB-MRI in oncologic imaging are addressed and compared to the results of PET/CT.

Purpose Lesions close to the internal craniocervical ligaments are a common problem in patients with whiplash injuries. The aim of this study was to evaluate the morphology and visibility of these ligamentous structures with a new isotropic three-dimensional (3D) turbo-spin-echo (TSE) technique. Materials and Methods MR (MR) images of the cervical spine of 52 healthy subjects (27 women and 25 men; mean age=29 years; age range=18–40 years) were taken with a T2-weighted 3D TSE sequence with variable flip-angle distribution [SPACE (Sampling Perfection with Application optimized Contrasts using different flip-angle Evolution)] at 1.5 T (Magnetom Avanto, Siemens Erlangen, Germany). Two experienced musculoskeletal radiologists read the images independently on a 3D imaging and postprocessing workstation. The visibility and morphology of the alar ligaments were evaluated on a five-point scale, and inter-reader correlation was assessed with kappa statistics. Results Both alar ligaments were detected in all subjects. Twenty-eight (53.8%) of the alar ligaments could not be seen within one slice of the standard coronal imaging plane but could adequately be visualized in an oblique reconstruction adapted to the orientation of the ligaments on the axial slices. Inter-reader correlation for visibility on MR imaging (MRI) of the internal craniocervical ligaments was high (left+right side, kappa=0.95). Most (94%) alar ligaments presented symmetrically. In the axial plane, 60% were oriented neutral and 40% had a backward orientation. In the coronal plane, 67% were oriented caudocranially and 33% were oriented horizontally. The shape of the ligaments was parallel in half and was V -shaped in the other half. The alar ligaments had homogeneous low-signal intensity in 56% and heterogeneous low-signal intensity in 44%. The apical ligament of the dens was seen (excellent–good–moderate) in 61% (reader 1) and 52% (reader 2). The tectorial membranes and the transverse ligament of the atlas were shown (excellent–good) in all subjects. Conclusions MRI with acquisition of an isotropic SPACE technique allows high-resolution imaging of the craniocervical ligaments in all orientations. Reconstruction of the image data in the variable orientation of the alar ligaments allowed for excellent depiction within one slice such that partial volume artifacts that hamper image analysis can be eliminated.

The advent of whole-body MRI (WB-MRI) has introduced tumor imaging with a systemic approach compared to established sequential, multi-modal diagnostic algorithms. Hardware innovations, such as the introduction of multi-receiver channel whole-body scanners at 1.5 T and recently 3 T, combined with acquisition acceleration techniques, have made high resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution and contrast media dynamics can be combined with whole-body anatomic coverage in a multi-planar imaging approach. More flexible protocols, e.g. including T1-weighted TSE- and STIR-imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen can be performed within less than 45 min. For initial tumor staging PET-CT as a competing whole-body modality in oncologic imaging has proved more accurate for the definition of T-stage and lymph node assessment, using the additional metabolic information of PET for the assessment of tumor viability and therapy response. However, new applications, such as MR-whole-body diffusion imaging, may significantly increase sensitivity in near future. WB-MRI has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and it is especially useful as a radiation-free alternative for the surveillance of tumor patients with multiple follow-up exams. Furthermore, it has been introduced as a whole-body bone marrow screening application. Within this context WB-MRI is highly accurate for the detection of skeletal metastases and staging of hematologic diseases, such as multiple myeloma or lymphoma. This article summarizes recent developments and applications of WB-MRI and highlights its performance within the scope of systemic oncologic staging and surveillance.

For bone marrow screening, multimodality algorithms including conventional radiographs, bone scintigraphy, multislice computed tomography CT (MS-CT) scan, and dedicated magnetic resonance imaging (MRI) are widely established in clinical routine. Although radiographs are used as a basic imaging procedure for clarification of suspected focal bone pathologies, low sensitivity has been reported for the detection of limited osteolytic bone marrow destruction. Therefore, skeletal scintigraphy often is used as a more sensitive and integrated method in patients with suspected malignant bone marrow disease. MS-CT scan is the method of choice in the assessment of bone stability and allows for evaluation of fracture risk. Hybrid imaging concepts, such as positron emission tomography-computed tomography (PET-CT) scan, have been established as an effective tool for the detection of skeletal metastases, using the additional metabolic information of a PET scan for the assessment of tumor viability and therapy response. MRI is an imaging technique that allows direct visualization of bone marrow components with high spatial resolution. The unique soft-tissue contrast of MRI enables precise assessment of bone marrow infiltration before osteolytic changes become visible in MS-CT or metabolic changes occur in bone scintigraphy or a PET scan. Furthermore it can depict tumor expansion into adjacent paraosseous structures, such as the spinal canal. The development of multichannel whole-body MRI (WB-MRI) systems has enabled bone marrow screening without use of ionizing radiation at high diagnostic accuracy. Parallel imaging techniques in combination with global matrix coil concepts, as well as the introduction of high-field whole-body scanners, have substantially reduced acquisition times without compromises in spatial resolution. WB-MRI has successfully been applied for screening of bone metastases and hematologic bone marrow diseases, like multiple myeloma, lymphoma, and histiocytosis X. Furthermore, it has recently been proposed for the assessment of primarily benign bone diseases predisposing for malignancy (e.g., multiple cartilaginous exostoses). This article provides an overview of state-of-art whole-body imaging of the bone marrow and highlights present and potential future applications, especially in the field of WB-MRI.

The purpose of this study was to assess the diagnostic accuracy of whole-body MRI (WB-MRI) at 1.5 T or 3 T compared with FDG-PET-CT in the follow-up of patients suffering from colorectal cancer. In a retrospective study, 24 patients with a history of colorectal cancer and suspected tumour recurrence underwent FDG-PET-CT and WB-MRI with the use of parallel imaging (PAT) for follow-up. High resolution coronal T1w-TSE and STIR sequences at four body levels, HASTE imaging of the lungs, contrast-enhanced T1w- and T2w-TSE sequences of the liver, brain, abdomen and pelvis were performed, using WB-MRI at either 1.5 T (n = 14) or 3 T (n = 10). Presence of local recurrent tumour, lymph node involvement and distant metastatic disease was confirmed using radiological follow-up within at least 5 months as a standard of reference. Seventy seven malignant foci in 17 of 24 patients (71%) were detected with both WB-MRI and PET-CT. Both investigations concordantly revealed two local recurrent tumours. PET-CT detected significantly more lymph node metastases (sensitivity 93%, n = 27/29) than WB-MRI (sensitivity 63%, n = 18/29). PET-CT and WB-MRI achieved a similar sensitivity for the detection of organ metastases with 80% and 78%, respectively (37/46 and 36/46). WB-MRI detected brain metastases in one patient. One false-positive local tumour recurrence was indicated by PET-CT. Overall diagnostic accuracy for PET-CT was 91% (sensitivity 86%, specificity 96%) and 83% for WB-MRI (sensitivity 72%, specificity 93%), respectively. Examination time for WB-MRI at 1.5 T and 3 T was 52 min and 43 min, respectively; examination time for PET-CT was 103 min. Initial results suggest that differences in accuracy for local and distant metastases detection using FDG-PET-CT and WB-MRI for integrated screening of tumour recurrence in colorectal cancer depend on the location of the malignant focus. Our results show that nodal disease is better detected using PET-CT, whereas organ disease is depicted equally well by both investigations.

To analyze the impact of altered magnetic field properties on image quality and on potential artifacts when an established whole-body magnetic resonance imaging (WB-MRI) protocol at 1.5 Tesla (T) is migrated to 3 T.Fifteen volunteers underwent noncontrast magnetic resonance imaging (MRI) on 32-channel whole body-scanners at 1.5 and 3 T with the use of parallel acquisition techniques (PAT). Coronal T1-weighted TSE- and short tau inversion recovery (STIR)-sequences at 4 body levels including sagittal imaging of the whole spine were performed. Additional axial HASTE-imaging of lung and abdomen, T1-/T2-weighted-TSE- and EPI-sequences of the brain and T2-weighted respiratory-triggered imaging of the liver was acquired. Both data sets were compared by 2 independent readers in respect to artifacts and image quality using a 5-point scale. Regions of pronounced artifacts were defined.Overall image impression was both qualitatively rated as "good" at 1.5 and 3 T for T1-w-TSE- and STIR-imaging of the whole body and spine. At 1.5 T, significantly better quantitative values for overall image quality were found for WB-STIR, T2-w-TSE imaging of the liver and brain (Wilcoxon Mann-Whitney U Test; P0.05), overall rated as good at 3 T. Significantly higher dielectric effects at 3 T were affecting T1-w- and STIR-WB-MRI, and HASTE of the abdomen and better image homogeneity at 1.5 T was observed for T1-weighted-/STIR-WB-MRI and T1-w-TSE-imaging of the spine. Pulsation artifacts were significantly increased at 3 T for T1-w WB-MRI. Significantly higher susceptibility artifacts were found for GRE-sequences of the brain at 3 T. Motion artifacts, Gibbs-Ringing, and image distortion was not significantly different and showed slightly higher quantitative values at 3 T (except for HASTE imaging of the abdomen). Overall scan time was 45 minutes and 44 seconds at 1.5 T and 40 minutes and 28 seconds at 3 T at identical image resolution.Three Tesla WB-MRI is feasible with good image quality comparable to 1.5 T. 3.0 T WB-MRI shows significantly more artifacts with a mild to moderate impact on image assessment. Therefore 1.5 T WB-MRI is the preferred image modality. Overall scan time at 3 T is reduced with the use of parallel imaging at a constant image resolution.

OBJECTIVE To test the hypothesis that apparent diffusion coefficient (ADC) in vertebral bone marrow of benign and malignant fractures is related to the volume of the interstitial space, determined with dynamic contrast-enhanced (DCE) magnetic resonance imaging. METHODS Patients with acute benign (n = 24) and malignant (n = 19) vertebral body fractures were examined at 1.5 T. A diffusion-weighted single-shot turbo-spin-echo sequence (b = 100 to 600 s/mm) and DCE turbo-FLASH sequence were evaluated. Regions of interest were manually selected for each fracture. Apparent diffusion coefficient was determined with a monoexponential decay model. The DCE magnetic resonance imaging concentration-time curves were analyzed using a 2-compartment tracer-kinetic model. RESULTS Apparent diffusion coefficient showed a significant positive correlation with interstitial volume in the whole study population (Pearson r = 0.66, P < 0.001), as well as in the malignant (Pearson r = 0.64, P = 0.004) and benign (Pearson r = 0.52, P = 0.01) subgroup. A significant correlation between ADC and the permeability-surface area product could be observed when analyzing the whole study population (Spearman rs = 0.40, P = 0.008), but not when separately examining the subgroups. Plasma flow showed a significant correlation with ADC in benign fractures (Pearson r = 0.23, P = 0.03). Plasma volume did not show significant correlations with ADC. CONCLUSIONS The results support the hypothesis that the ADC of a lesion is inversely correlated to its cellularity. This explains previous observations that ADC is reduced in more malignant lesions.

The diagnostic accuracy of screening for bone metastases was evaluated using whole-body magnetic resonance imaging (WB-MRI) compared with combined fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) (FDG-PET-CT). In a prospective, blinded study, 30 consecutive patients (18 female, 12 male; 24-76 years) with different oncological diseases and suspected skeletal metastases underwent FDG-PET-CT as well as WB-MRI with the use of parallel imaging (PAT). With a 32-channel scanner, coronal imaging of the entire body and sagittal imaging of the complete spine was performed using T1-weighted and short tau inversion recovery (STIR) sequences in combination. PET-CT was conducted using a low-dose CT for attenuation correction, a PET-emission scan and diagnostic contrast-enhanced CT scan covering the thorax, abdomen and pelvis. Two radiologists read the MRI scans, another radiologist in combination with a nuclear medicine physician read the PET-CT scans, each in consensus. The standard of reference was constituted by radiological follow-up within at least 6 months. In 28 patients, 102 malignant and 25 benign bone lesions were detected and confirmed. WB-MRI showed a sensitivity of 94% (96/102), PET-CT exams achieved 78% (79/102; P0.001). Specificities were 76% (19/25) for WB-MRI and 80% (20/25) for PET-CT (P0.05). Diagnostic accuracy was 91% (115/127) and 78% (99/127; P0.001), respectively. Cut-off size for the detection of malignant bone lesions was 2 mm for WB-MRI and 5 mm for PET-CT. WB-MRI revealed ten additional bone metastases due to the larger field of view. In conclusion, WB-MRI and FDG-PET-CT are robust imaging modalities for a systemic screening for metastatic bone disease. PAT allows WB-MRI bone marrow screening at high spatial resolution and with a diagnostic accuracy superior to PET-CT.

The objective of this study was to compare the accuracy in staging of various malignant tumors with whole-body magnetic resonance imaging (WB-MRI) using parallel imaging (PAT) and positron emission tomography-computed tomography (PET-CT).In a prospective study, 41 patients withoncologic diseases underwent [F]-fluoro-2-deoxy-D-glucose PET-CT for tumor staging and WB-MRI on a 32-channel-scanner with the use of PAT. Coronal T1w and STIR sequences at 5 body levels, axial HASTE imaging of the lung, and contrast-enhanced T1w sequences of the liver, brain, and abdomen were performed. TNM stage was assessed for both modalities in a separate consensus reading using histologic results and radiologic follow up within 6 months as the standard of reference.Three primary and 4 recurrent tumors were detected; one recurrent tumor was missed with WB-MRI. Sixty benign and 60 malignant lymph nodes were detected with a sensitivity of 98% and specificity of 83% for PET-CT and 80%/75% for WB-MRI, respectively. One hundred ninety-one malignant and 77 benign distant lesions were detected with a sensitivity/specificity of 82% for PET-CT and 96%/82% for WB-MRI. Accuracy for correct TNM staging was 96% for PET-CT and 91% for WB-MRI.WB-MRI and PET-CT are reliable imaging modalities for tumor staging. WB-MRI is highly sensitive in detecting distant metastases; PET-CT is superior in lymph node staging. PAT makes high-resolution WB-MRI feasible within less than 1 hour.

Purpose To determine the detection of diffuse bone marrow infiltration with MRI in comparison with histopathological findings. Materials and methods MRI was performed on 45 patients with histologically proven multiple myeloma and on 30 healthy individuals. Three experienced radiologists read separately Tl-weighted SE sequences, STIR sequences and the combination of Tl-weighted SE and STIR sequences of the spine. Additionally, Tl-weighted SE sequences were obtained after gadolinium administration and the percentage increase in signal intensity was calculated. Bone marrow histology was used as gold standard for assessing the grade of infiltration. A dichotomous decision (infiltration yes/no) was made when assessing the MRI examinations. Results For the visual detection of diffuse infiltration, the best sensitivity was found with Tl-weighted SE sequences, achieving 71 % on average. The specificity was 89 %. The STIR sequences showed a sensitivity of 61 % and a specificity of 98 %, and the combination of Tl-weighted/STIR-sequences achieved a sensitivity of 65 % and a specificity of 94 %. In comparison with the histological findings, the sensitivity of the Tl-weighted sequences was 35 % for low-grade, 89 % for moderate and 100 % for high-grade infiltration. The application of contrast material with calculation of the percentage signal increase improved the detection by 7 %. Conclusion The sensitivity of the visual detection of diffuse multiple myeloma with unenhanced MRI is limited for low-grade or moderate infiltration, whereas the sensitivity for high grade infiltration is reliable. The specificity is high and the diagnostic confidence improves after application of contrast material with calculation of the percentage increase in signal intensity.

Tumor staging according to the TNM-system influences prognosis and therapeutical options of patients with a malignant disease. It is the challenge of diagnostic imaging to depict the exact localization of the primary tumor and to detect or rule out lymph node involvement or distant metastases. In doing so, the complete body anatomy should be covered with a modality that offers high sensitivity and specificity. As these requirements could not or only partially be achieved by previous ordinary procedures, the use of multiple different modalities became necessary. Last but not least, in consideration of the costs it would be preferable to replace this cascade of different modalities by a "whole body examination", preconditioned that the same accuracy is achieved.With PET/CT and whole-body MRI, two newly available promising methods for a systemic tumor staging have been developed. First experiences indicate PET/CT as a method of first choice. With the introduction of new whole-body MRI scanners using parallel imaging technique (iPAT) and free table movement, MRI plays a more and more important role in whole body tumor staging.

To evaluate diagnostic performance of gallium 68-tetraazacyclododecane tetraacetic acid-octreotate ((68)Ga-DOTATATE) in detection of recurrent neuroendocrine tumors (NETs).Approval was waived by the local ethics committee for this retrospective study. Between 2007 and 2011, 63 patients (mean age, 58 years) were examined with (68)Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) after primary NET curative resection. Reasons for PET/CT were regular follow-up examinations (n = 30), increased plasma levels of tumor markers (n = 27), or clinical suspicion of recurrence (n = 6). Final diagnosis was determined with histopathologic verification (n = 25) or clinical follow-up (n = 38). PET/CT scans were evaluated in consensus by two readers without blinding to clinical information and independently by two readers with blinding. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.Final diagnosis of NET recurrence was determined in 29 patients. In three other patients, tumors of nonneuroendocrine origin were diagnosed. (68)Ga-DOTATATE PET/CT helped identify NET recurrence in 26 of 29 patients (sensitivity, 90%) and exclude presence of recurrent NET in 28 of 34 patients (specificity, 82% ). PET/CT provided false-positive and false-negative results in six and three patients (PPV, 81% [26 of 32]; NPV, 90% [28 of 31]; accuracy, 86% [54 of 63]). In gastroenteropancreatic NET (n = 45), sensitivity was 94% (17 of 18); specificity was 89% (24 of 27); PPV was 85% (17 of 20); NPV was 96% (24 of 25); and accuracy was 91% (41 of 45). Two blinded readers achieved sensitivity of 79% (23 of 29) and 76% (22 of 29); specificity of 85% (29 of 34) and 94% (32 of 34) (κ = 0.80); and accuracy of 83% and 86%.(68)Ga-DOTATATE PET/CT is accurate in detection of recurrent NET. Blinded PET/CT review markedly decreased sensitivity, underlining importance of considering clinical parameters in NET recurrence. Present results must be further validated to substantiate use of (68)Ga-DOTATATE PET/CT in routine follow-up after curative resection of NET.

The objective of our study was to evaluate quantitative dynamic contrast-enhanced MRI (DCE-MRI) based on tracer kinetic modeling of perfusion in the differentiation of benign from malignant vertebral fractures.Patients with 26 osteoporotic vertebral fractures (18 women, eight men; mean age, 69 years) and patients with 20 malignant vertebral fractures (nine women, 11 men; mean age, 63.4 years) underwent dynamic contrast-enhanced MRI. T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. Dynamic contrast-enhanced image sets were acquired with a 2D saturation-recovery spoiled gradient-echo sequence. Regions of interest in parameter maps of mean transit time (MTT) and plasma flow in the fractured vertebral bodies were analyzed with a two-compartment tracer kinetic model. Plasma flow, plasma volume (PV), extraction flow, and interstitial volume were calculated. The forward volume transfer constant (K(trans)) and the extracellular volume (ECV) were derived. A two-tailed Fisher exact test, Mann-Whitney U test, and receiver operating characteristic analysis were performed.Forty-four vertebral fractures in 44 patients could be evaluated. In spots of increased plasma flow, interstitial volume (p = 0.0003), ECV (p = 0.002), and extraction flow (p = 0.03) for osteoporotic and malignant vertebral fractures were significantly different. The mean interstitial volume was 28.62 mL/100 mL for osteoporotic fractures and 11.73 mL/100 mL for malignant fractures, and the area under the curve (AUC) was 0.819 for a cutoff of 11.72 mL/100 mL or less indicating malignancy (sensitivity, 63.2%; specificity, 96.0%). The mean ECV was 52.68 mL/100 mL for osteoporotic fractures and 36.71 mL/100 mL for malignant fractures, and the AUC was 0.802 for a cutoff of 35.83 mL/100 mL or less indicating malignancy (sensitivity, 63.2%; specificity, 92.0%). The mean extraction flow was 15.19 mL/100 mL/min for osteoporotic fractures and 23.67 mL/100 mL/min for malignant fractures, and the AUC was 0.693 for a cutoff of 6.52 mL/100 mL/min or less indicating malignancy (sensitivity, 57.9%; specificity, 92.0%). K(trans), plasma flow, and PV in the spots of increased plasma flow and all quantitative perfusion parameters in the regions of increased MTT did not show any significant differences between benign and malignant fractures.In spots of high plasma flow, which can be determined with a deconvolution analysis, the quantitative perfusion parameters of interstitial volume, ECV, and extraction flow are significantly different between acute osteoporotic and malignant vertebral fractures and can aid in the distinction between the two entities.

The skeletal system is a frequent target of metastatic spread from various primary tumors such as carcinoma of the breast, lung and prostate cancer. Therefore, it is highly important to accurately assess skeletal metastases in order to facilitate adequate therapy and predict patients’ prognosis. However, only pronounced destruction of bone with loss of mineral content exceeding 50% is readily visible in radiographic examinations. Computed tomography (CT) is definitely more sensitive than radiography and it is the imaging modality of choice to evaluate the extent of destruction of trabecular and cortical bone and to assess stability and fracture risk. Magnetic resonance imaging (MRI), on the other hand, allows visualization of bone marrow structure, such as hematopoietic—and fat cell components. Moreover, tumor infiltration into the spinal canal and paravertebral soft tissues is clearly depicted. The combination of unenhanced T1-weighted-spin echo- and turbo-STIR-sequences has shown to be most useful for the detection of bone marrow abnormalities and is able to discriminate benign from malignant bone marrow changes. Compared with other imaging modalities like radiography, CT or bone scintigraphy, it is the most sensitive technique for the detection of bone marrow pathologies, even if trabecular bone is not destroyed. Recently, multi-channel whole-body MRI (WB-MRI) scanners have been introduced and allow for head-to-toe assessment of the whole skeletal system without compromises in image quality compared with dedicated examinations of limited anatomical areas. Accordingly, WB-MRI has become a useful and sensitive alternative to standard whole-body imaging procedures such as skeletal scintigraphy or whole-body CT.

Radioembolization of primary and secondary liver tumors has emerged as valuable treatment option. CT and especially MRI are very helpful in delineating the tumors and estimating the liver involvement and are still considered as standard in oncologic imaging. Diffusion-weighted MRI has shown promising results in very early treatment assessment in a recent study. However, traditional therapy monitoring using RECIST or WHO criteria may be hampered by the specific changes of tumors treated with radioembolization. Multi-modal imaging, especially in the case of whole-body imaging, may overcome these drawbacks and provide more precise prognostic stratification due to the additional metabolic information. Recent studies indicate an advantage of FDG PET/CT in therapy montoring of radioembolization, in particular in cholangiocellular charcinoma, breast cancer and colorectal cancer. Further on, whole-body MRI has shown to be useful in pre-therapeutic triage of patients and the diagnosis of extra-hepatic metastases.

We hypothesized that (68)Ga-DOTATATE uptake of neuroendocrine tumors is sensitive to therapy with a nonradioactive somatostatin analog.(68)Ga-DOTATATE PET/CT was used to examine 105 patients, 35 of whom had been pretreated with long-acting octreotide. The maximum standardized uptake value (SUV(max)) of target tissues, as well as metastases, was compared between the groups of patients with (group 1) and without (group 2) octreotide treatment.The SUV(max) of the spleen and liver was significantly lower in group 1 than in group 2 (both P0.001). There were no significant group differences in SUV(max) for primary tumors (28.6 ± 6.8 vs. 32.9 ± 31.5) or metastases in the liver (27.2 ± 14.8 vs. 25.7 ± 10.7), lymph nodes (41.4 ± 19.5 vs. 25.0 ± 6.3), or skeleton (39.5 ± 22.0 vs. 15.4 ± 7.8). In 9 patients available for intraindividual comparison, tumor uptake was unaffected by treatment with somatostatin analogs (21.7 vs. 20.6; P = 0.93).Treatment with a long-acting somatostatin analog did not significantly reduce (68)Ga-DOTATATE binding in neuroendocrine tumors but tended to improve the tumor-to-background ratio.

water , , S S accord- ing to (5), which depend on the relaxation times, T1 and T2, and the ADCs of both signal components as well as on the sequence parameters (repetition time TR, diffusion gradient shape, and the flip angle). Methods: MRI was performed on a 1.5-T whole-body scanner in 40 patients with benign (n=20) or malignant (n=20) VLs to determine the fat fraction and tissue parameters (ADC, T1, T2, T2 * ) for both the water and fat signal component (using single-shot turbo-spin-echo (ssTSE) sequences for ADC, T1, and T2 quanti- fication, and gradient-echo sequences for fat-fraction and T2 * quantification). With these values, the DW-SSFP signal was simulated and compared with the measured signals (PSIF diffusion sequence: TE = 7.17 ms, TR = 25 ms, flip angle 40°; diffusion gradient 23 mT⁄m, duration δ = 0.5,1.5,3.0,5.0,7.4 ms) for different diffusion gradients. Simulations and measurement results were compared by determining the signal ratios RVL between the SSFP signals of the lesions and of normal-appearing VBM for both malignant and benign vertebral lesions. Results: The simulated DW-SSFP contrast agreed well with the measured con- trast (cf. Fig. 1) and provided a very good differentiation between benign osteopo- rotic and malignant VLs with a sensitivity of up to 95% and a specificity of 100%. ADCs were significantly different in both lesion types; however, the great- est contributions to the observed total image contrast resulted from the differences (between both patient groups) of ffat in the lesions as well as in normal-appearing VBM, of T * 2,fat in normal-appearing VBM, and of T * 2,water in the lesions (cf. Fig. 2). Smaller effects are caused by the differences of T1,fat and T2,fat in normal- appearing VBM and (with opposite sign) of T2,water in the lesions. The other para- meter differences do not contribute substantially to the observed contrast. Conclusions: In this study, we could confirm previous results that the DW- SSFP sequence provides an excellent differentiation between benign osteoporotic and malignant VLs. We could also show that the main reasons for the different lesion contrasts (hypo-/isointense vs. hyperintense signal) are an opposed-phase readout in combination with the differing fat fractions and T2 * -values in the le- sions as well as in normal-appearing VBM of both entities. The observed signal contrast is therefore rather fat- and T2 * -weighted than diffusion-weighted. The intermediate diffusion weighting of the applied SSFP sequence, however, helps to shift the different contrasts into a signal range that is easily visually accessible.

Lung cancer is the leading cause of cancer mortality. Bone metastases are a common complication in lung cancer. The therapeutic approach and the type of surgical treatment of these lesions have not been clearly defined. Outcome and prognosis of patients with bony metastases and a variety of surgical interventions were analysed retrospectively. In 58 patients we performed 62 surgeries. The most common locations of metastases were the spine (32 patients), the proximal femur (10) and the pelvis (11). Twenty-one patients had a singular and 20 had multiple osseous lesions; 17 showed additional visceral involvement. Nine patients had a local progression of their disease and 49 a systemic progression. Patients with local progression (n = 9) had a better prognosis than the patients with systemic progression (p = 0.0083). Fracture (p = 0.0017) worsened prognosis, whereas the number of bone lesions or the presence of a visceral lesion did not. Patients with small lesions showed a better survival than patients with large lesions (p = 0.02). Ten percent of the patients died within 30 days and 78% within one year after surgery. Fracture of bone due to metastatic lung cancer worsens the prognosis whereas the number of bone lesions, the presence of a visceral lesion and the surgical approach do not.

To evaluate the potential and to analyze parameter correlations of combined quantitative diffusion-weighted MRI (DWI) and high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) in vertebral bone marrow (vBM) of patients with osteoporosis and acute vertebral compression fractures, providing additional information for a better understanding of the physiological background of parameter changes.20 patients with acute osteoporotic fractures were examined with DWI and DCE-MRI at 1.5 T. DCE-MRI was performed with a 2D saturation-recovery turbo-FLASH sequence, acquiring 300 dynamics with a temporal resolution of 1 s. For DWI measurements, a DW HASTE sequence with b-values from 100 to 600 s/mm² was applied. In each patient, ROIs were drawn manually in the fractures and in normal appearing vertebrae. For DCE-MRI, the concentration-time curves of these ROIs were analyzed using a two-compartment tracer-kinetic model in the lesions, providing separate estimates of perfusion and permeability, and a one-compartment model in normal vBM, providing only a mixed representation of perfusion and permeability in terms of a mixed flow parameter K(trans) and the extracellular volume (ECV). In the case of DWI, attenuation curves were fitted to a monoexponential decay model to determine the apparent diffusion coefficient (ADC).Mean perfusion parameters and ADCs were significantly (p0.001) different in the fractures compared to adjacent normal appearing vertebrae (K(trans): 7.81 mL/100 mL/min vs. 14.61 mL/100 mL/min, ECV: 52.84 mL/100 mL vs. 4.61 mL/100 mL, ADC: 1.71×10⁻³ mm²/s vs. 0.57×10⁻³ mm²/s). ADCs showed a significant correlation with the ECV.The quantitative analysis of DWI and DCE-MRI could distinguish osteoporotic fractures from normal appearing vertebrae. A significant correlation found between ECV and ADCs might be able to explain the cause for the increased diffusivity in osteoporotic fractures. Since the other perfusion parameters do not correlate with the ADC, they provide additional pathophysiological information not accessible with DWI.

To evaluate spin-lattice (T1) and spin-spin (T2) relaxation times as well as apparent diffusion coefficients (ADCs) of the fat and water components in the vertebral bone marrow (vBM) of patients with benign and malignant lesions. Forty-four patients were examined at 1.5 T: there were 24 osteoporotic vertebral fractures (15 women, 9 men; median age: 73, 48–86 years) and 20 malignant vertebral infiltrations (9 women, 11 men; median age: 60, 25–87). Relaxation times were determined separately for the water and the fat component using a saturation-recovery technique for T1 and measurements with variable echo times for T2. ADCs were determined with a diffusion-weighted (DW) echo-planar imaging (EPI) and a single-shot turbo-spin-echo (ssTSE) sequence. T1 of the water component and ADCs were significantly increased in the lesions compared with normal-appearing vBM (malignant: 1,252 vs. 828 ms, osteoporotic: 1,315 vs. 872 ms). ADCs determined with the DW-ssTSE were significantly increased compared with the DW-EPI. ADCs determined with the DW-ssTSE differed significantly between osteoporotic and malignant lesions $$ \left( {1.74\;{\hbox{vs}}\;{1}{.35} \times {10} ^{ - 3}\,{\hbox{m}}{{\hbox{m}}^2}/{\hbox{s}}} \right) $$ . All parameters exhibit significant differences between normal-appearing vBM and the lesions. However, only the ADCs determined with the DW-ssTSE differed significantly between osteoporotic fractures and malignant lesions, potentially allowing for a differential diagnosis of these two entities.

Purpose: To retrospectively assess an improved quantitative methodology with separate assessment of perfusion and permeability for characterization of primary renal cell carcinoma (RCC) and monitoring antiangiogenic treatment. Materials and Methods: Fifteen RCC patients before surgery, 6 RCC patients before and after neoadjuvant antiangiogenic therapy, and 15 patients without renal disease underwent dynamic contrast-enhanced (DCE)-MRI of the kidney with integrated retrospective respiratory triggering and an individual arterial input function. Tracer kinetic analysis was performed with a two-compartment-filtration-model for the kidney data and a two-compartment-exchange-model for the tumor data, providing four independent parameters: the perfusion-parameters plasma flow (FP) and plasma volume (VP), and the permeability-parameters extraction flow (FE) and extravascular-extracellular volume (VE). Results: In tumors FP and FE were significantly lower than in normal kidneys. Tracer kinetic analysis displayed hemodynamic alteration caused by vessel infiltration or necrosis. Papillary RCC could be differentiated from clear-cell variants by a distinct perfusion pattern. In antiangiogenically treated RCC VE was not significantly decreased, while the perfusion parameters VP and FP were significantly diminished. Conclusion: DCE-MRI with integrated motion compensation enables evaluation of primary RCC and detects distinct perfusion patterns. Quantification with a two-compartment-exchange-model produces a separate perfusion- and permeability characterization and may become a diagnostic tool to monitor antiangiogenic treatment. J. Magn. Reson. Imaging 2010; 31: 490–501. © 2010 Wiley-Liss, Inc.

The introduction of whole-body magnetic resonance imaging (WB-MRI) has fundamentally changed diag­nostic concepts for imaging of various systemic diseases in recent years. As an alternative to multi-modal­ity imaging approaches, whole-body techniques are now increasingly applied in clinical routine, especially for an integrated imaging of malignant disease. However, the crucial problem for implementing WB-MRI in the past has been to integrate substantially different requirements in coil setup, contrast media application, slice positioning, and sequence design into one single comprehensive scan. Significant improvements in hardware, from pioneering approaches using a rolling platform system mounted on top of a conventional MRI scanner to the essential introduction of state-of the-art multi-channel whole-body scanners with automated free table movement, have cleared the way for clinically feasible and efficient total body imaging concepts. Furthermore, important innovations in sequence design and image acquisition physics, such as parallel acquisition techniques (PATs), have helped to significantly reduce overall examination times without compromising spatial resolution, and have increased patient comfort and acceptance. Now a dedicated assessment of various organs by sequences with adequate soft tissue contrast, image orientation, spatial resolution, and contrast media dynamics can be combined with whole-body anatomic coverage.

Purpose To compare the diagnostic accuracy for the detection of tumor recurrence in breast cancer patients using whole-body-MRI (WB-MRI) at 1.5 or 3 T compared to FDG–PET–CT. Materials and methods Thirty-three female patients with breast cancer and suspicion of recurrence underwent FDG–PET–CT and WB-MRI. Coronal T1w-TSE- and STIR-sequences, HASTE-imaging of the lungs, contrast-enhanced T1w- and T2w-TSE-sequences of the liver, brain and abdomen were performed, using a WB-MRI-scanner at 1.5 (n = 23) or 3 T (n = 10). Presence of local recurrence, lymph node involvement and distant metastatic disease was assessed using clinical and radiological follow-up as a standard of reference. Results Tumor recurrence was found in 20 of 33 patients. Overall 186 malignant foci were detected with WB-MRI and PET–CT. Both modalities revealed two recurrent tumors of the breast. PET–CT detected more lymph node metastases (n = 21) than WB-MRI (n = 16). WB-MRI was more precise in the detection of distant metastases (n = 154 versus n = 147). Sensitivity was 93% (172/186) and 91% (170/186) for WB-MRI and PET–CT, specificity was 86% (66/77) and 90% (69/77), respectively. Examination times for WB-MRI at 1.5 and 3 T were 51 and 43 min, respectively, examination time for PET–CT was 103 min. Conclusion WB-MRI and PET–CT are useful for the detection of tumor recurrence in the follow-up of breast cancer. WB-MRI is highly sensitive to distant metastatic disease. PET–CT is more sensitive in detecting lymph node involvement. Tumor screening with WB-MRI is feasible at 1.5 and 3 T, scan time is further reduced at 3 T with identical resolution.

Objective: The value of combined positron emission tomography (PET)/computed tomography (CT) in the follow-up of patients with breast cancer with elevated tumor markers but without proven metastases or local recurrence was assessed. Methods: Thirty-four women underwent PET/CT. The PET and CT images were first analyzed separately; fused findings were then interpreted, blinded to the results of the other modalities. The results of CT, PET, and PET/CT were compared with each other and correlated to the final diagnosis. Results: The PET/CT identified 149 malignant foci in 24 patients (71%). The CT detected 96 of these foci in 18 patients, whereas PET identified 124 foci in 17 patients. Differences between CT and PET were not significant. Differences between PET/CT and CT (P < 0.01) and PET/CT and PET (P < 0.01) were significant. The person-based sensitivity of PET/CT, PET, and CT was 96%, 88% and 96%, respectively. Specificity of PET/CT, PET, and CT was 89%, 78%, and 78%, respectively. Conclusions: The PET/CT is a valuable modality for the follow-up of patients with breast cancer and elevated levels of tumor markers.

The advent of positron emission tomography-computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) has introduced tumor imaging with a systemic and functional approach compared with established sequential, multimodal diagnostic algorithms.Whole-body PET with [18F]-fluoro-2-desoxy-glucose is a useful imaging procedure for tumor staging and monitoring that can visualize active tumor tissue by detecting pathological glucose metabolism. The combination of PET with the detailed anatomical information of multislice computed tomography as dual-modality scanners has markedly increased lesion localization and diagnostic accuracy compared with both modalities as standalone applications.Hardware innovations, such as the introduction of multi-receiver channel whole-body MRI scanners at 1.5 and, recently, 3 T, combined with acquisition acceleration techniques, have made high-resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution, and contrast media dynamics can be combined with whole-body anatomical coverage in a multiplanar imaging approach. More flexible protocols (eg, T1-weighted turbo spin-echo and short inversion recovery imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen) can be performed within 45 minutes.Whole-body magnetic resonance imaging has recently been proposed for tumor screening of asymptomatic individuals, and potentially life-changing diagnoses, such as formerly unknown malignancy, have been reported. However, larger patient cohort studies will have to show the cost efficiency and the clinical effectiveness of such an approach.For initial tumor staging, PET-CT has proved more accurate for the definition of T-stage and lymph node assessment, mainly because of the missing metabolic information in WB-MRI. However, new applications, such as magnetic resonance whole-body diffusion-weighted imaging or lymphotropic contrast agents, may significantly increase sensitivity in near future. Whole-body magnetic resonance imaging has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and as a whole-body bone marrow screening application. Within this context, WB-MRI is highly accurate for the detection of skeletal metastases and staging of multiple myeloma. This article summarizes recent developments of CT/PET-CT and WB-MRI and highlights their performance within the scope of systemic oncological imaging.

In clinical practice various modalities are used for whole-body imaging of the musculoskeletal system, including radiography, bone scintigraphy, computed tomography, magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT). Multislice CT is far more sensitive than radiographs in the assessment of trabecular and cortical bone destruction and allows for evaluation of fracture risk. The introduction of combined PET-CT scanners has markedly increased diagnostic accuracy for the detection of skeletal metastases compared with PET alone. The unique soft-tissue contrast of MRI enables for precise assessment of bone marrow infiltration and adjacent soft tissue structures so that alterations within the bone marrow may be detected before osseous destruction becomes apparent in CT or metabolic changes occur on bone scintigraphy or PET scan. Improvements in hard- and software, including parallel image acquisition acceleration, have made high resolution whole-body MRI clinically feasible. Whole-body MRI has successfully been applied for bone marrow screening of metastasis and systemic primary bone malignancies, like multiple myeloma. Furthermore, it has recently been proposed for the assessment of systemic bone diseases predisposing for malignancy (e.g., multiple cartilaginous exostoses) and muscle disease (e.g., muscle dystrophy). The following article gives an overview on state-of-the-art whole-body imaging of the musculoskeletal system and highlights present and potential future applications, especially in the field of whole-body MRI.