Multi-parametric MRI of rectal cancer - do quantitative functional MR measurements correlate with radiologic and pathologic tumor stages?

PURPOSE: The purpose of this study is two-fold. First, to evaluate, whether functional rectal MRI techniques can be analyzed in a reproducible manner by different readers and second, to assess whether different clinical and pathologic T and N stages can be differentiated by functional MRI measurements. MATERIALS AND METHODS: 54 patients (38 men, 16 female; mean age 63.2 ± 12.2 years) with pathologically proven rectal cancer were included in this retrospective IRB-approved study. All patients were referred for a multi-parametric MRI protocol on a 3 Tesla MR-system, consisting of a high-resolution, axial T2 TSE sequence, DWI and perfusion imaging (plasma flow -s PFTumor) prior to any treatment. Two experienced radiologists evaluated the MRI measurements, blinded to clinical data and outcome. Inter-reader correlation and the association of functional MRI parameters with c- and p-staging were analyzed. RESULTS: The inter-reader correlation for lymph node (ρ 0.76-0.94; p<0.0002) and primary tumor (ρ 0.78-0.92; p<0.0001) apparent diffusion coefficient and plasma flow (PF) values was good to very good. PFTumor values decreased with cT stage with significant differences identified between cT2 and cT3 tumors (229 versus 107.6 ml/100ml/min; p=0.05). ADCTumor values did not differ significantly. No substantial discrepancies in lymph node ADCLn values or short axis diameter were found among cN1-3 stages, whereas PFLn values were distinct between cN1 versus cN2 stages (p=0.03). In the patients without neoadjuvant RCT no statistically significant differences in the assessed functional parameters on the basis of pathologic stage were found. CONCLUSION: This study illustrates that ADC as well as MR perfusion values can be analyzed with good interobserver agreement in patients with rectal cancer. Moreover, MR perfusion parameters may allow accurate differentiation of tumor stages. Both findings suggest that functional MRI parameters may help to discriminate T and N stages for clinical decision making.

CT-based response assessment of advanced gastrointestinal stromal tumor: dual energy CT provides a more predictive imaging biomarker of clinical benefit than RECIST or Choi criteria.

OBJECTIVES: Dual-energy CT (DECT) allows quantification of intravenously injected iodinated contrast media in tumors, and therefore may be considered as a surrogate marker for perfusion and tumor vascularity. This study evaluated whether newly developed DECT response criteria allow better correlation with survival than established response criteria. METHODS: Seventeen patients with advanced GIST treated with tyrosine-kinase-inhibitors were assessed by contrast-enhanced DECT 2 and 6 months after beginning of treatment. Response to treatment of 165 tumor lesions was evaluated according to RECIST, Choi criteria and newly developed DECT criteria, defining non-responders as an increase of both tumor size >20% and iodine related attenuation or either a >50% increase of tumor size or iodine related attenuation. All other patients were classified as responders. Progression-free survival (PFS) and overall survival (OS) were calculated by Kaplan-Meier analysis. RESULTS: Choi criteria and DECT showed a significantly longer median PFS of patients rated as responders than patients rated as non-responders (9-29 months vs. 2-6 months; p<0.02) at follow-up. Only DECT analysis at 6 months follow-up allowed a valid prediction of OS. CONCLUSION: This study indicates that DECT allows a better prediction of therapeutic benefit in advanced GIST patients treated with tyrosine-kinase-inhibitors than established response criteria. However, the most important predictive biomarker of therapeutic benefit was absence of progression, no matter which response evaluation criteria were applied.

Assessment of the diagnostic value of dual-energy CT and MRI in the detection of iatrogenically induced injuries of anterior cruciate ligament in a porcine model.

INTRODUCTION: Magnetic resonance imaging (MRI) is the standard of reference for the non-invasive evaluation of ligament injuries of the knee. The development of dual-energy CT (DE-CT) made it possible to differentiate between tissues of different density by two simultaneous CT measurements with different tube voltages. This approach enables DE-CT to discriminate ligament structures without intra-articular contrast media injection. The aims of this study were on the one hand to determine the delineation of the anterior cruciate ligament (ACL) and on the other hand to assess the diagnostic value of DE-CT and MRI in the detection of iatrogenically induced injury of the ACL in a porcine knee joint model. MATERIALS AND METHODS: Twenty porcine hind legs, which were placed in a preformed cast in order to achieve a standardized position, were scanned using DE-CT. Thereafter, a 1.5-T MRI using a standard protocol was performed. The imaging procedures were repeated with the same parameters after inducing defined lesions (total or partial incision) on the ACL arthroscopically. After post-processing, two radiologists and two orthopedic surgeons first analyzed the delineation of the ACL and then, using a consensus approach, the iatrogenically induced lesions. The result of the arthrotomy was defined as the standard of reference. RESULTS: The ACL could be visualized both on DE-CT and MRI in 100% of the cases. As for the MRI, the sensitivity and specificity of detecting the cruciate ligament lesion respectively compared with the defined arthrotomy was 66.7% and 78.6% for intact cruciate ligaments, 100% and 75% in the case of a complete lesion, 33.3% and 78.6% for lesions of the anteromedial bundle, and 0% and 100% for lesions of the posterolateral bundle. In comparison, DE-CT demonstrated a sensitivity and specificity of 66.7% and 71.4% in the case of intact cruciate ligaments, 75% and 68.8% in the case of completely discontinued ACLs, 0% and 92.9% in the case of lesions of the anteromedial bundle, and 25% and 87.5% in the case of lesions of the posterolateral bundle. CONCLUSIONS: The present ex vivo experiment shows that both study modalities (DE-CT and MRI) are equal with regard to the delineation of the ACL, while MRI achieved higher sensitivity and specificity regarding iatrogenically induced complete ACL lesions. DE-CT could be a possible alternative to MRI for certain indications in the diagnosis of a knee ligament injury.

[Multiparametric prostate MRI for follow-up monitoring after radiation therapy]. / Multiparametrische MRT der Prostata zum Therapiemonitoring nach Strahlentherapie.

CLINICAL/METHODICAL ISSUE: Radiation therapy is a therapeutic option with curative intent for patients with prostate cancer. Monitoring of prostate-specific antigen (PSA) values is the current standard of care in the follow-up. Imaging is recommended only for symptomatic patients and/or for further therapeutic options. STANDARD RADIOLOGICAL METHODS: For detection of local recurrence magnetic resonance imaging (MRI) of the prostate is acknowledged as the method of choice. PERFORMANCE: Good results for primary diagnosis were found especially in combination with functional techniques, whereas in recurrent prostate cancer only few studies with heterogeneous study design are available for prostate MRI. Furthermore, changes in different MRI modalities due to radiation therapy have been insufficiently investigated to date. PRACTICAL RECOMMENDATIONS: As the initial results were promising prostate MRI and available therapeutic options for detection of local recurrence should be considered in patients with increased PSA.

Functional imaging of lung cancer using dual energy CT: how does iodine related attenuation correlate with standardized uptake value of 18FDG-PET-CT?

OBJECTIVES: To investigate the correlation between maximum standardized uptake value (SUV(max)) of (18)FDG PET-CT and iodine-related attenuation (IRA) of dual energy CT (DECT) of primary tumours and (18)FDG PET-CT positive thoracic lymph nodes (LN) in patients with lung cancer. METHODS: 37 patients with lung cancer (27 NSCLC, 10 SCLC, 86 (18)FDG PET-CT positive thoracic LN) who underwent both (18)FDG PET-CT and DECT were analyzed. The mean study interval between (18)FDG PET-CT and DECT was ≤21 days in 17 patients. The mean and maximum IRA of DECT as well as of virtual unenhanced and virtual 120 kV images of DECT was analyzed and correlated to the SUV(max) of (18)FDG PET-CT in all tumours and (18)FDG PET-CT positive thoracic lymph nodes. Further subgroup analysis was performed for histological subtypes in all groups. RESULTS: A moderate correlation was found between SUV(max) and maximum IRA in all tumours (n = 37;r = 0.507;p = 0.025) whereas only weak or no correlation were found between SUV(max) and all other DECT measurements. A strong correlation was found in patients with study intervals ≤21 days (n = 17; r = 0.768;p = 0.017). Analysis of histological subtypes of lung cancer showed a strong correlation between SUV(max) and maximum IRA in the analysis of all patients with NSCLC (r = 0.785;p = 0.001) and in patients with NSCLC and study intervals ≤21 days (r = 0.876;p = 0.024). Thoracic LN showed moderate correlation between SUV(max) and maximum IRA in patients with study intervals ≤21 days (r = 0.654; p = 0.010) whereas a weak correlation was found between SUV(max) and maximum IRA in patients with study intervals >21 days (r = 0.299; p = 0.035). CONCLUSIONS: DECT could serve as a valuable functional imaging test for patients with NSCLC as the IRA of DECT correlates with SUV(max) of (18)FDG PET-CT.

[Whole-body MRI in preoperative diagnostics of breast cancer--a comparison with [corrected] staging methods according to the S 3 guidelines]. / Ganzkörper-MRT in der präoperativen Diagnostik des Mammakarzinoms--ein Vergleich mit den Stagingmethoden in der S 3-Leitlinie.

PURPOSE: The German Society of Senology (step-3 guidelines for the early recognition of breast cancer in Germany) recommends whole-body staging including chest X-ray, ultrasound of the liver and bone scintigraphy before systemic therapy in patients with breast cancer. The performance of these three examinations is time-consuming and involves radiation exposure. Whole-body MR imaging (WB-MRI) allows staging in a single examination without radiation exposure. The purpose of this study was to compare the diagnostic accuracy of WB-MRI with staging according to the guidelines. MATERIALS AND METHODS: During 04/07 and 06/09, the initial staging in 51 patients (56 ± 12 yrs) with breast cancer (24 patients with lymph node metastases) was performed according to the S 3-guidelines. Additionally, all patients underwent contrast-enhanced WB-MRI (1.5-Tesla-Magnetom Avanto, Siemens, Erlangen). The findings of the different modalities were compared after correlation of the lesions by follow-up. The detection of suspicious findings and the accuracy of prediction of malignancy of the detected lesions were evaluated. RESULTS: Overall, 14 metastases were detected in 4 of 51 patients after completion of the follow-up. By means of WB-MRI, all 14 metastases could be detected, while just 4 of these metastases were identified by the conventional methods. CONCLUSION: The detection of distant metastases has an important impact on patient management. In this study WB-MRI in breast cancer staging has shown promising results in regard to possible clinical implementation as a matter of routine staging.

Scintigraphic evaluation of rhBMP-2-biocoated implants reveals no ectopic bone formation.

The main objectives of the study described below were of two-fold nature: (1) to examine if rhBMP-2-biocoated implants in a pig model could lead to ectopic bone formation and (2) if quantitative and/or qualitative differences could be found between adhesively and covalently bonded BMP II using the scintigraphic method. In order to examine these central questions, 26 Göttingen minipigs were allocated to three groups with a control group (n=7) and two study groups (n=9 each) receiving one of three implant types: (a) chromosulfuric acid treated titanium surface as control, (b) non-covalently bonded BMP-2, and (c) covalently bonded and immobilized rhBMP-2. Each animal received four barbell-shaped implants, one in the proximal and distal metaphysis of each femur. The scintigraphic analyses were conducted after four, eight, and 12 weeks postoperatively. The visual (qualitative) analysis failed to show ectopic bone formation in any of the three groups. The statistical analysis of the relative values for bone formation yielded no significant differences between the groups, although the limitation in the applied methods do not enable one to draw conclusions regarding the histomophometric results.

[Imaging diagnostics of the prostate]. / Bildgebung der Prostata.

Prostate cancer is the most common malignancy of men with approximately 32,000 new cases of prostate cancer in Germany and approximately 11,000 men who would die of the disease each year. For early diagnosis of prostate cancer PSA testing is used, whereas at present screening cannot be recommended due to the lack of confirmed medical and economic benefits. Regarding the imaging modalities, ultrasound of the prostate, currently performed in combination with elastography and histoscanning, magnetic resonance imaging of the prostate in combination with endorectal coils and positron emission tomography combined with computed tomography (PET-CT) are the methods of choice. Using these methods benign prostatitis can be differentiated from prostate cancer and staging of the tumor can be accomplished. On the other hand using these imaging methods it is possible to define the dominant intraprostatic lesion with different sensitivities and specificities, which is important for minimally invasive therapeutic strategies.

Comparison of a new whole-body continuous-table-movement protocol versus a standard whole-body MR protocol for the assessment of multiple myeloma.

OBJECTIVES: To evaluate a whole body (WB) continuous-table-movement (CTM) MR protocol for the assessment of multiple myeloma (MM) in comparison to a step-by-step WB protocol. METHODS: Eighteen patients with MM were examined at 1.5T using a WB CTM protocol (axial T2-w fs BLADE, T1-w GRE sequence) and a step-by-step WB protocol including coronal/sagittal T1-w SE and STIR sequences as reference. Protocol time was assessed. Image quality, artefacts, liver/spleen assessability, and the ability to depict bone marrow lesions less than or greater than 1 cm as well as diffuse infiltration and soft tissue lesions were rated. Potential changes in the Durie and Salmon Plus stage and the detectability of complications were assessed. RESULTS: Mean protocol time was 6:38 min (CTM) compared to 24:32 min (standard). Image quality was comparable. Artefacts were more prominent using the CTM protocol (P = 0.0039). Organ assessability was better using the CTM protocol (P < 0.001). Depiction of bone marrow and soft tissue lesions was identical without a staging shift. Vertebral fractures were not detected using the CTM protocol. CONCLUSIONS: The new protocol allows a higher patient throughput and facilitates the depiction of extramedullary lesions. However, as long as vertebral fractures are not detectable, the protocol cannot be safely used for clinical routine without the acquisition of an additional sagittal sequence.

[Imaging of prostate cancer by diagnostic radiology and nuclear medicine]. / Radiologisch-nuklearmedizinische Bildgebung des Prostatakarzinoms.

The diagnostic methods in radiology and nuclear medicine for the imaging of prostate cancer as well as for the detection of locoregional recurrent disease and positive lymph nodes have progressed dramatically over the past years. Regarding technical advances in magnetic resonance imaging (MRI) and the new tracers used in nuclear medicine, an increase in sensitivity up to 85-90% and in specificity up to 75-90% has been achieved. Especially in MRI, efforts had been made to implement multiparametric imaging using the diagnostic methods of spectroscopy and diffusion-weighted sequences and by including dynamic contrast enhancement studies. In addition, by the use of dedicated, lymph-node specific contrast media, "ultrasmall paramagnetic iron particles" (USPIO), up to 100% of all pathological lymph nodes were detected in the published studies. Also in the field of nuclear medicine there have been relevant advances such as the development of specific tracer substances, which can be coupled to 18fluorine, a nuclide that is characterised by a longer half-life time than 11C and is therefore usable even in sites without an in-house cyclotron. Using this nuclide, the sensitivity and specificity rates in the detection of primary prostate cancer as well as in locoregional recurrences have been increased to values between 85 and 95%.

Blood volume flow quantification of the brain-supplying circulation in fibromuscular dysplasia using 2D cine phase-contrast MRI.

To determine blood volume flow (BVF) in the brain-supplying arteries in patients with fibromuscular dysplasia (FMD), we used two-dimensional cine phase-contrast MR blood flow quantification to evaluate haemodynamic compromise. Nine patients with angiographically proven FMD (mean age, 46.7+/-10.4 years) of the cervical and intracranial arteries were examined using two-dimensional phase contrast MR to measure blood flow in the carotid arteries and the basilar artery (BA). Quantitative BVF results were compared intra- and inter-individually and also with the results of 15 age-matched normal controls. No patient showed evidence of acute or chronic infarction of the brain. FMD lesions were found in a total of 19 arteries (internal carotid artery: n = 14; vertebral arteries: n = 5). Five patients demonstrated severe stenoses of cervical vessels; four patients showed only mild or up to moderate stenoses. Total brain BVF in all FMD patients reached high-normal values compared with normal controls (747+/-64 ml min(-1) vs 682+/-38 ml min(-1)). In the five patients with severe stenotic lesions, blood flow was reduced in stenotic vessels and higher in the non-haemodynamically relevant stenosed cervical vessels. BVF was normal in the four patients with mild and moderate stenoses. By quantifying blood flow, we demonstrated for the first time changes (which can be severe) in the BVF of the brain-supplying arteries in FMD. Individual differences are associated with the haemodynamic relevance of the FMD lesions. Total BVF in patients with severe FMD was not decreased but maintained or even increased, possibly as an overcompensation.

[Shoulder injuries in overhead athletes: utility of MR arthrography]. / Schulterverletzungen des Uberkopfsportlers: Wertigkeit der MR-Arthrografie.

INTRODUCTION: The goal of this work was to assess the accuracy of the MR-Arthrografie in the evaluation of over head athletes injuries in comparison with athroscopy. MATERIAL AND METHODS: In 29 patients (middle age: 30 years, 21 male, 8 female, age 16 - 53 years) with persistent pain after conservative therapy an Arthro-MRI with intraarticular application of gadolinum was performed prior to arthroscopic surgery. The MRI was retrospectivly analysed of three examiners independently from one another. The result were compared to the results of the Arthroscopy. Interrater Reliability was calculated by using of Cohens Kappa. RESULTS: The MR-Arthrography could demonstrate 8 of 9 (88.9 %) partial tears of he rotator cuff. All SLAP (Superiores Labrum from Anterior to Posterior) Lesions as well as all bankart type Lesions were recognized through the MR-Arthrography. However, dependent upon the experience of the examiner in a span between 33.3 % (fellow radiologist) and 93.3 % (consultant radiologist). We found a high agreement between consultant radiologist and shoulder surgeon with Kappa of 0.79 for rotator cuff tear-, 0.86 for Bankart- and 0.82 for SLAP-Läsionen.

Myocardial iron overload in transfusion-dependent pediatric patients with acute leukemia.

For patients who regularly receive blood transfusions, cardiac failure is the major cause of death. This is most alarming because it progresses rapidly and is difficult to manage. We present three pediatric patients with acute leukemia whose therapy-induced anemia was treated with different amounts of red blood cell concentrates (RCC). In all patients, a liver iron overload was measured by super-conducting interference device (SQUID) biosusceptometry and magnetic resonance imaging (MRI). MRI is a rapid, noninvasive, and widely available method of determining early myocardial iron overload caused by multiple blood transfusion due to anemia during polychemotherapy.

[Cardiac MR imaging in arrhythmogenic heart diseases]. / Kardiale MRT in der Diagnostik arrhythmogener Herzerkrankungen.

INTRODUCTION: Cardiac arrhythmias are assessed with a combination of history, clinical examination, electrocardiogram, Holter monitor, if necessary supplemented by invasive cardiac electrophysiology. In ischemic heart disease (IHD) coronary angiography is performed in addition. METHODS: Echocardiography is usually the primary imaging modality. MRI is increasingly recognized as an important investigation allowing more accurate cardiac morphological and functional assessment. RESULTS: Approximately one-fifth of deaths in Western countries are due to sudden cardiac death, 80% of which are caused by arrhythmias. Typical causes range from diseases with high prevalence (IHD in men 30%) to myocarditis (prevalence 1-9%) and rare cardiomyopathies (prevalence HCM 0.2%, ARVC 0.02%, Brugada syndrome approx. 0.5%). The characteristic MRI features of arrhythmogenic diseases and the new aspects of characteristic distribution of late enhancement allow etiologic classification and differential diagnosis. CONCLUSION: MRI represents an important tool for detection of the underlying cause and for risk stratification in many diseases associated with arrhythmias.