Body Phased-array Coil Research Articles

Comparison of synthesized and acquired high b-value diffusion-weighted MRI for detection of prostate cancer

BackgroundHigh b-value diffusion-weighted images (DWI) are used for detection of clinically significant prostate cancer (csPCa). This study qualitatively and quantitatively compares synthesized DWI (sDWI) to acquired (aDWI) for detection of csPCa.MethodsOne hundred fifty-one consecutive patients who underwent prostate MRI and biopsy were included in the study. Axial DWI with b = 0, 500, 1000, and 2000 s/mm2 using a 3T clinical scanner using a 32-channel phased-array body coil were acquired. We retrospectively synthesized DWI for b = 2000 s/mm2 via extrapolation based on mono-exponential decay, using b = 0 and b = 500 s/mm2 (sDWI500) and b = 0, b = 500 s/mm2, and b = 1000 s/mm2 (sDWI1000). Differences in signal intensity between sDWI and aDWI were evaluated within different regions of interest (prostate alone, prostate plus 5 mm, 30 mm and 70 mm margin and full field of view). The maximum DWI value within each ROI was evaluated for prediction of csPCa. Classification accuracy was compared to Restriction Spectrum Imaging restriction score (RSIrs), a previously validated biomarker based on multi-exponential DWI. Discrimination of csPCa was evaluated via area under the receiver operating characteristic curve (AUC).ResultsWithin the prostate, mean ± standard deviation of percent mean differences between sDWI and aDWI signal were -46 ± 35% for sDWI1000 and -67 ± 24% for sDWI500. AUC for aDWI, sDWI500, sDWI1000, and RSIrs within the prostate 0.62[95% confidence interval: 0.53, 0.71], 0.63[0.54, 0.72], 0.65[0.56, 0.73] and 0.78[0.71, 0.86], respectively.ConclusionsDWI is qualitatively comparable to aDWI within the prostate. However, hyperintense artifacts are introduced with sDWI in the surrounding pelvic tissue that interfere with quantitative cancer detection and might mask metastases. In the prostate, RSIrs yields superior quantitative csPCa detection than sDWI or aDWI.

MO636THE ROLE OF DIFFUSION-WEIGHTED MRI AND APPARENT DIFFUSION COEFFICIENT IN ASSESSMENT OF DIABETIC KIDNEY DISEASE: PRELIMINARY EXPERIENCE STUDY

Abstract Background and Aims Diabetic kidney disease is the most common cause of ESRD. There is poor correlation between the degree of renal fibrosis and current screening markers. A noninvasive imaging technique is needed to assess the degree of structural changes in the kidney. Method Forty adult diabetic patients with chronic kidney disease as well as 20 age- and sex-matched adult healthy controls were recruited from Nephrology Department of our University Hospital. All patients underwent renal MR-DWI and ADC mapping on a 1.5-T scanner (Philips Achieva) using phased array body coil. Results Among the studied 40 diabetic patients, five groups of patients were resulted 8 patients for each and the ADC values were inversely correlated with advancement in renal parenchymal affection, ie, in late stages of the disease the ADC values were lower than in early stages. The mean ADC values of renal parenchyma in patients with diabetic kidney disease were considerably lower than that of healthy controls with normal renal function (2.1± 0.3x10− 3 mm2/s vs 2.4± 0.1x10− 3 mm2/s with p< 0.001). Conclusion ADC value is a possible noninvasive technique in evaluating the stage of renal dysfunction with assessment of disease progression.

Role of Multiparametric Prostate Magnetic Resonance Imaging before Confirmatory Biopsy in Assessing the Risk of Prostate Cancer Progression during Active Surveillance

ObjectiveTo evaluate the impact of multiparametric magnetic resonance imaging (mpMRI) before confirmatory prostate biopsy in patients under active surveillance (AS).Materials and MethodsThis retrospective study included 170 patients with Gleason grade 6 prostate cancer initially enrolled in an AS program between 2011 and 2019. Prostate mpMRI was performed using a 1.5 tesla (T) magnetic resonance imaging system with a 16-channel phased-array body coil. The protocol included T1-weighted, T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging sequences. Uroradiology reports generated by a specialist were based on prostate imaging-reporting and data system (PI-RADS) version 2. Univariate and multivariate analyses were performed based on regression models.ResultsThe reclassification rate at confirmatory biopsy was higher in patients with suspicious lesions on mpMRI (PI-RADS score ≥ 3) (n = 47) than in patients with non-suspicious mpMRIs (n = 61) and who did not undergo mpMRIs (n = 62) (66%, 26.2%, and 24.2%, respectively; p < 0.001). On multivariate analysis, presence of a suspicious mpMRI finding (PI-RADS score ≥ 3) was associated (adjusted odds ratio: 4.72) with the risk of reclassification at confirmatory biopsy after adjusting for the main variables (age, prostate-specific antigen density, number of positive cores, number of previous biopsies, and clinical stage). Presence of a suspicious mpMRI finding (adjusted hazard ratio: 2.62) was also associated with the risk of progression to active treatment during the follow-up.ConclusionInclusion of mpMRI before the confirmatory biopsy is useful to stratify the risk of reclassification during the biopsy as well as to evaluate the risk of progression to active treatment during follow-up.

Role of Imaging in Rare Obstructive Reproductive Tract Anomalies: an Enigma—a Case Report

Mullerian duct anomalies (MDAs) result from abnormalities occurring during the embryologic development of mullerian ducts. Among the various mullerian abnormalities, obstructive reproductive tract anomalies (ORTA) form an interesting and difficult group to diagnose. This case series emphasize the role of imaging, specifically magnetic resonance imaging (MRI) in evaluating such cases before surgery. The clinical presentation of ORTA is in two ways, either with primary amenorrhea and pain or with menstrual periods and progressive dysmenorrhea. In ORTA, it is important to identify the site of obstruction, as surgical management depends upon the site of obstruction. Hence, the role of imaging is important in such cases. When suspecting MDAs especially ORTA, an initial screening ultrasound should be followed by MRI because of its multiplanar capability, excellent soft tissue characterization, and absence of ionizing radiation. All MRI examinations in our study were performed using 3 T MRI system using a phased array body coil. Here we are reporting three rare cases of ORTA presented to our institute where MRI identified the exact site of obstruction before surgery, leading to better preoperative planning. Hence MRI should be mandatory part of workup of this group of patients.

Diagnostic Accuracy of MR-Spectroscopy in Diagnosis of Focal Liver Malignant Lesions Taking Histopathology as Gold Standard

Objective: To determine the diagnostic accuracy of MR-spectroscopy in diagnosis of focal liver malignant lesions taking histopathology as gold standard. Study Design: Cross-Sectional Validation Study. Settings: The study was conducted in Radiology Department of Allied Hospital Faisalabad. Duration: Six months from 1st October 2017 to 31st March 2018. Methodology: Permission for research was sought from hospital ethical committee. Patients were collected from OPD & indoor departments of Radiology and Medicine of Allied Hospital Faisalabad. Objective of study was explained to every subject who fulfilled the inclusion criteria and informed consent was taken. Confounding variables were controlled by restriction (by excluding subjects with history of metastatic disease and chemotherapy). MRS examination was performed with the patients in supine position using 1.5-T Philips MRI unit and a body phased array coil. This procedure was performed in Radiology Department Allied Hospital Faisalabad. Biopsy was taken from the patients and histopathology was done from histopathology lab PMC/Allied Hospital Faisalabad. Finally, the data was collected. Results: In this study, diagnostic accuracy of MR-spectroscopy in diagnosis of focal liver malignant lesions taking histopathology as gold standard was calculated as 93.75% for sensitivity, 90.20% for specificity, 92.31% for positive predictive value, 92.00% for negative predictive value and 92.17% for accuracy rate, positive likelihood ratio was 9.56 and negative likelihood ratio was 0.07. Conclusion: It is concluded that the diagnostic accuracy of MR-spectroscopy is comparable and is better as it is less invasive in diagnosing of focal liver malignant lesions taking histopathology as gold standard. However, these findings are primary and needs validation through some other local studies.

MR diffusion imaging in mediastinal masses the differentiation between benign and malignant lesions

Abstract Purpose Diffusion-weighted imaging is a fundamental tool integrated in MR protocols useful in differentiating benign from malignant mediastinal masses, assessing mediastinal lymphadenopathy and investigating central bronchogenic carcinoma. This method is an excellent alternative to CT or PET/CT in the investigation of mediastinal masses. Current applications of diffusion MRI in malignancies include monitoring the treatment response and detecting recurrent cancer. Aim of the Work This study aims to assess the value of using MRI diffusion in differentiating benign and malignant mediastinal masses, differentiating central masses from post obstructive collapse and differentiating lymphoma versus sarcoidosis. Patients and Methods This study included 30 patients; 16 males and 14 females in the period from June 2013 to July 2014. The mean age was 49.3 ± 16.85 (range: 22–82 years). Cases were referred for MRI assessment and were approved by the ethical committee in our department. The complaints varied between dyspnea, chest pain, cough, hemoptysis, fatigue and loss of weight. A superconducting 1.5 T MRI machine with a four-channel body phased-array coil was used for the examination. Biopsy and histopathological assessment was done after that. Results MRI examination with diffusion imaging was able to differentiate between benign and malignant mediastinal and hilar lesion confirmed by the biopsy and histopathology. Conclusion MRI with diffusion weighted images can detect and stage lung cancer, differentiate benign from malignant mediastinal masses and differentiate lymphoma from sarcoidosis in mediastinal/hilar lymphadenopathy.

Role of Diffusion Weighted Magnetic Resonance Imaging in Characterization of Pulmonary Masses

Abstract Background: Lung malignancy is the most common cause of death in the developed countries. Male to female ratio is 3:1. Consumption of Tobacco upsurges the rate of evolving lung cancer by 30 folds. Other risk factors include repeated exposure to aspects like carcinogens, asbestos, pulmonary fibrosis and radiotherapy. Aim of Study: The aim of this study is to assess the role of diffusion weighted magnetic resonance imaging in charac-terization of pulmonary masses. Patients and Methods: This study was carried out on forty (40) patients 8 females and 32 males who had Pulmonary mass on the X-ray or CT chest and aged above 18 years old. All the studied patients underwent to detailed history taking, laboratory studies and radiological examination using MRI (GE 1.5 Tesla) using body phased-array Coil and DWI (b-value 0, 500, and 800s/mm2). Results: Thirty lesions were malignant, and 10 lesions were benign. The malignant masses showed significantly higher signal intensity on DWI than benign masses (p<0.001), and the mean ADC value of malignant lesions was significantly lower than that of benign lesions (p<0.001). By ROC curve, an ADC cut-off value of 1.6 X 10–3mm2/s was considered the threshold value, and the sensitivity and specificity were 100% and 90% respectively. Conclusion: Diffusion-weighted MRI and ADC can sig-nificantly differentiate between benign and malignant pulmo-nary masses.

Diagnostic accuracy of perfusion weighted MRI in differentiating neoplastic and non-neoplastic brain lesions using histopathology as Gold standard.

Objectives: Perfusion-weighted imaging may be performed as a complementary examination to conventional MRI techniques. The clinical applications of PWI in the evaluation of focal brain lesions include the differentiation between neoplastic and non-neoplastic brain lesions, primary tumors and solitary metastasis and, in the post-treatment follow up, the differentiation of tumoral recurrence and radio necrosis. To determine the diagnostic accuracy of perfusion weighted MRI in differentiating. Neoplastic and non-neoplastic brain lesions keeping histopathology as gold standard. Study Design: Cross sectional (validation) study. Setting: The study was conducted in Radiology department of Allied Hospital Faisalabad. Period: Six months from 25-March-2016 to 24-Sep-2016. Material and Methods: Permission for this study was taken from the hospital ethical review committee. A total of 125 patients were included and MRI examination was performed with the patients in supine position using a 1.5-T Philips MRI unit and a body phased-array coil. A preload of paramagnetic contrast agent (gadolinium) was administered 30 seconds before acquisition of dynamic images, followed by a standard dose 10 seconds after starting imaging acquisitions. Results: Patients ranged between 15-65 years of age. Mean age of the patients was 47.6±10.6 years. There were 65 males (52%) and 60 females (48%). PW MRI showed sensitivity 81.67%, specificity 81.54%, positive predictive value 80.33%, negative predictive value 82.81% and diagnostic accuracy 81.60%. ROC and likelihood ratio was measured for age and gender. For age (15-40 years) likelihood ratio was 7.187 and for age 41-65 likelihood ratio was 48.665. For males likelihood ratio was 31.759 while for females 16.188. Conclusion: In conclusion, our results suggest a promising role for perfusion MR imaging in the distinction between neoplastic and non-neoplastic lesions.

Value of Intravoxel Incoherent Motion for Hepatocellular Carcinoma Grading

BackgroundTo evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) parameters in estimation of hepatocellular carcinoma (HCC) grading. Materials and methodsTwenty-nine patients with histopathologically diagnosed as 42 HCC at explant were included in this retrospective study. All patients were examined by 1.5T magnetic resonance imaging with the use of 4-channel phased array body coil. In addition to routine pre- and postcontrast sequences, IVIM (16 different b factors varying from 0 to 1300 s/mm2) and conventional diffusion-weighted imaging (3 different b factors of 50, 400, 800 s/mm2) were obtained with single-shot echo planar spin echo sequence. Apparent diffusion coefficient (ADC) and IVIM parameters including mean D (true diffusion coefficient), D* (pseudo-diffusion coefficient associated with blood flow), and f (perfusion fraction) values were calculated. Histopathologically, HCC was classified as low (grade 1, 2) and high (grade 3, 4) grade in accordance with the Edmondson-Steiner score. Quantitatively, ADC, D, D*, and f values were compared between the low- and high-grade groups by Student t test. The relationship between the parameters and histologic grade was analyzed using the Spearman’s correlation test. To evaluate the diagnostic performance of the parameters, receiver operating characteristic analysis was performed. ResultsHigh-grade HCCs had significantly lower ADC and D values than low grade groups (P = .005 and P = .026, retrospectively); ADC and D values were inversely correlated with tumor grade (r = –0.519, P = .011, r = –0.510, P = .026, respectively). High-grade HCCs had significantly higher f values when compared with the low-grade group (P = .005). The f values were positively correlated with tumor grade (r = 0.548, P = .007). The best discriminative parameter was f value. Cut-off value of 32% of f values showed sensitivity of 75.6% and a specificity of 73.5%. ConclusionADC values and IVIM parameters such as f values appear to reflect the grade of HCCs.

Perianal fistula imaging: a comparison between two-channel superficial Flex coil and eight-channel body coil.

PurposePerianal fistula is an important health problem with devastating morbidity. For diagnosis and prevention of recurrence, perianal fistula imaging (PFI) is crucial. The aim of this study was to investigate if a Flex-M superficial coil images would provide more information than images obtained with a phased-array body coil in PFI.Material and methodsThirty-one fistulas of 29 patients were prospectively evaluated with magnetic resonance imaging. A phased-array body coil was used in all patients as in routine practice, and sequences with Flex-M coil were also obtained. Afterwards, images were evaluated by two experienced radiologists who were blinded to the patients, coil and also to each other. The site of internal and external openings, and presence or absence of abscess and secondary tracts were recorded.ResultsThe conspicuity of images was better with the Flex-M coil. Both radiologists saw more internal openings with the Flex-M coil. Cohen’s κ value was 0.100 (p = 0.201) for Reader 1 and 0.110 (p = 0.361) for Reader 2 between these two coils. Additionally, numerically more internal/external openings and secondary tracts were seen by both readers. Interobserver variability was not statistically significant, and Cohen’s κ values signifyied good concordance between readers.ConclusionsIn our study we showed that multichannel superficial phased-array coils improved imaging quality in PFI. We think that Flex-M coil can easily be used in routine clinical practice to gather better images of perianal fistulas.

Role of Magnetic Resonance Cholangiopancreatography in Evaluation of Biliary Obstruction

Background: obstructive jaundice which is caused by bile duct obstruction can be clinically and biochemically indistinguishable from cholestatic jaundice caused by hepatocellular disease. The management of both these conditions being radically different, the principle task of the radiologist is to differentiate between hepatocellular and obstructive jaundice, by using available imaging modality and help in further management. With the availability of non-invasive modality like magnetic resonance imaging (MRI), it is possible to diagnose obstructive jaundice early and accurately without any patient discomfort. The purpose of this article is to describe the protocol for evaluation of obstructive jaundice with use of magnetic resonance cholangio pancreatography sequence of MRI and to describe the imaging features of the most common causes of obstructive jaundice like biliary calculi, bile duct strictures, choledochal cyst, gall bladder carcinoma, cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic head carcinoma. Aim of work: this work aimed to study and evaluate the role of MRCP in patients with biliary obstruction. Patients and Methods: this study included 30 patients with biliary obstruction during the period from December 2017 to October 2018. MRCP was performed on a 1.5 T MRI system, using a phased-array body coil. Fasting for 4 hours prior to the examination is required to reduce gastro-duodenal secretions, reduce motility to eliminate motion artifacts and to promote distension of gall bladder.For optimum visualization of ducts, acquired images were reformatted in different planes using multiplanar reconstruction (MPR) and maximum intensity projection (MIP). Results: in all cases, MRCP displayed the different parts of the biliary tract and localized the exact site of obstruction in all of the obstructed cases. According to the morphology encountered at the site of obstruction, MRCP was found highly specific in differentiating the calcular, malignant and benign causes of obstruction. The quality of images were degraded by the presence of massive ascites, marked patient obesity in our study by the instability to hold breath in a reproducible manner. Lack of the therapeutic role and the inability to perform functional studies mainly at the papilla remain the main limitation of the technique. Conclusion: MRCP should be the next step following depiction of biliary obstruction by U/S. Consequently in the near future there will be no place for the diagnostic use of the ERCP which shall be then restricted to a therapeutic role.

Role and Application of Diffusion-weighted Imaging in Evaluation of Prostate Cancer

Abstract Introduction: Diffusion-weighted imaging (DWI) is an important part of magnetic resonance imaging (MRI) in the evaluation of specific organs, including the breast, kidney, liver, and prostate. Prostate cancer lesions are composed of tightly packed cells with reduced extracellular space, which can be visualized on DWIs as areas of restricted diffusion (i.e., high-signal intensity), with corresponding low-signal intensity on apparent diffusion coefficient (ADC) maps and low mean ADC value. Objective: The objective of this study is to identify the appropriate cutoff and mean ADC value to diagnose neoplastic prostatic lesions in central India. Materials and Methods: Sixty-six patients with suspected prostatic pathology were included in this study. All patients underwent MRI on a 1.5-T scanner with a phased-array body coil. MRIs were evaluated compared with the histopathological staging. Results:: The diagnostic accuracy of DWI in predicting malignancy was 39/41, i.e., 95.12%, which is the positive predicted value. The mean ADC for benign category was 1.14 with standard deviation (SD) of 0.14 while mean for prostatitis was 0.91 with SD of 0.26 and for carcinoma was 0.75 with SD of 0.19. The difference in the means was statistically highly significant. Conclusion: DWI demonstrates the restriction of diffusion and the reduction of ADC values in neoplastic tissue and improves the diagnostic accuracy in lesion characterization. This technique allows short acquisition time and provides high-contrast resolution between neoplastic and normal tissue. This technique can be a useful adjunct to the established dynamic contrast-enhanced-MRI.

Role of PROPELLER-DWI of the prostate in reducing distortion and artefact from total hip replacement metalwork

ObjectiveTo compare image quality, artefact, and distortion in standard echo-planar imaging (EPI) with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) for prostate magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) in patients with previous total hip replacement (THR). Methods21 male subjects with a clinical suspicion for, or known prostate cancer and previous THR were scanned at 1.5 T using a phased-array body coil. DWI was obtained using single-shot EPI and PROPELLER techniques using fat saturation (PROPELLER-DWI-FS), and without (PROPELLER-DWI-NFS). Image quality (the overall impression of diagnostic quality) was compared to T2-weighted (T2WI) imaging using a 5-point Likert scale, with diffusion sequences additionally scored for artefact and distortion according to a 4-point scale, with artefact defined as the amount of prostate affected and distortion as the degree of warping of the organ. The T2W and DW image volumes were compared to produce quantitative distortion maps. A two-sample Wilcoxon test compared the qualitative scores, with inter-reader variability calculated using Cohen’s kappa. Results21 patients were included in the study, with an average age of 70.4 years and PSA 9.2 ng/ml. Hip metalwork was present bilaterally in 3 patients, left-sided in 9, and right-sided in 9.PROPELLER-DWI-FS significantly improved image quality (p < 0.01) and reduced distortion (p < 0.01) when compared to standard EP-DWI. Artefact was not shown to be significantly improved. The last 5 patients in the study were additionally imaged with PROPELLER-DWI-NFS, which resulted in a significant reduction in artefact compared to EP-DWI (p < 0.05). Quantitative distortion was significantly lower compared to EP-DWI for both PROPELLER with fat saturation (p < 0.01) and without fat saturation (p < 0.01). ConclusionPROPELLER-DWI demonstrates better image quality and decreases both artefact and distortion compared to conventional echo planar sequences in patients with hip metalwork.

Preoperative Stating of Pelvic Lymph Nodes in Prostate Cancer Patients via Endorectal Magnetic Resonance Imaging.

The aim of this study was to evaluate the diagnostic sensitivity, specificity and accuracy of endorectal magnetic resonance imaging (e-MRI), as a preoperative staging modality in the diagnosis of lymph node metastasis (LNM) in patients with prostate cancer (PCa). Retrospectively, we analyzed data from N=168 patients who underwent radical prostatectomy (RP) between 2004 and 2013 at two tertiary medical centres. Prior to RP all patients underwent an e-MRI. Inclusion criteria were: PSA levels >20 ng/ml or Gleason score >7. Examinations were performed on a closed 1.0-T system combined with an endorectal body phased-array coil, imaging results were correlated with histopathology. 10.7% (N=18 patients) had histologically-proven LNM. e-MRI was true-positive in N=6 (33.3%) and false-negative N=12 patients (66.6%). N=150 (89.3%) patients without LNM e-MRI were true-negative in 96% and false-positive in 4%. Sensitivity was 96%, specificity was 33%, accuracy was 64.5%. e-MRI can be considered a useful preoperative staging modality in diagnosis of LNM.

The Optimization of Isotropic 3D TSE (SPACE) MR Sequence for Daily Verification Imaging in Radiation Therapy of the Pelvis

The integration of MR-Simulator in RT workflow has sparked interest in the development of MRI-guided RT treatment protocols. The purpose of this study is to optimize an isotropic 3D TSE (SPACE) MR sequence for daily positional verification using MR-MR based imaging guidance in pelvic RT. T2-weighted (T2W) pelvic images of 10 male and 10 female healthy volunteers (age 23-45) were acquired in a 1.5T MRI-Simulator with a dedicated 18-channel phased-array body coil. Images were scanned in RT treatment position immobilized in a customized vacuum pillow system. Rapid imaging was achieved with partial Fourier techniques and with adjustments to ETL, NEX and iPAT, to generate a total of four axial 3D verification image sequences (MR-X) with a short acquisition time. Signal-to-noise ratio (SNR), TR, TE, BW, NEX and voxel size remained constant (Table 1). To avoid positional deviation, a high-resolution axial T2W 3D SPACE sequence (MR-Refx) was scanned as a reference (TR/TE: 1500/149ms, 1.17mm isotropic voxel) prior to the acquisition of each MR-X. Using four radiation therapist observers (10±5 years of experience), the impact of image quality of the four verification image sequences was investigated by employing both a qualitative analysis using a 7-point scale evaluation, based on delineation of organ outline and motion artifact, and a quantitative approach using a 6-DoF offline manual registration. The results were analysed using paired t-tests.Abstract 3656; Table 1MR-AMR-BMR-CMR-DTE (Echo Time)/TR (Repetition Time) (ms)147/1500147/1500147/1500147/1500Echo train length (ETL)217200217200Voxel size (mm)1.3x1.3x1.31.3x1.3x1.31.3x1.3x1.31.3x1.3x1.3BW (Bandwidth) (Hz/pixel)814814814814Parallel imaging factor (iPAT PE)3434Parallel imaging factor (iPAT 3D)3221Number of signals acquired (NEX)1111Partial Fourier (slice direction)OffOffOff6/8Acquisition time (min)1:151:301:562:41 Open table in a new tab Quantitatively, MR-A, with the shortest acquisition time, had a significantly larger shift error (p=0.007) in the Z translation direction with an average difference of 0.165mm compared with MR-RefA. MR-D, with the longest scan time, had a significantly larger yaw rotation (p=0.014) with a mean difference of 0.13o compared with MR-RefD. Qualitatively, the observers favored MR-D and MR-B sequences. MR-D and MR-B were not significantly different in image quality scores compared with their references. MR-B sequence had a high score, comparable to MR-RefB with bladder outline and visualization (p=0.212) and bladder motion artifact (p=0.124). MR-B is a promising imaging sequence. Not only was image quality not impeded to affect accurate registration but good visuals of the OARs and overall little artifact and noise were also reported. In this study, four MR sequences optimized for pelvic positional verification have been tested and the recommended image protocol, MR-B, has been identified based on image quality, registration accuracy and acquisition time.

Which organ should be considered a reference in diffusion weighted imaging of the abdomen?: The reproducibility of ADC measurements of the spleen and the renal cortex on a 1.5T MR.

Diffusion weighted imaging (DWI) is a useful tool for the evaluation of focal lesions in the liver or kidneys, as well as for the diagnosis and assessment of the liver fibrosis process. Some reports show that the spleen and kidneys may serve as reference organs in the staging of liver fibrosis or the evaluation of focal liver lesions. The aim of the study was to determine whether the spleen and renal cortex can be used as reference organs in the DWI technique. The study group included 36 patients with no liver, spleen or renal pathologies and without any infections or hematologic disease. All the examinations were performed using a 1.5T MR unit with a conventional phased array body coil. Image interpretation and apparent diffusion coefficient (ADC) measurements were done by 3 experienced radiologists. There was a statistically significant difference between the ADC values noted by 2 of the examiners in the upper/middle and lower part of the spleen parenchyma. There were no statistically significant differences between the ADC values obtained by all 3 examiners in all the parts of each kidney. There were no statistically significant differences between the examiners' ADC values for the spleen and kidneys. The mean ADC values for the left kidney showed the highest measurement reproducibility. The study showed that the renal cortex seems to be an appropriate region for performing reference ADC measurements. Further studies on a larger group of patients and using various DWI protocols should be performed to ascertain the best conditions for maximizing the reproducibility of ADC measurements.

Protocol optimization of sacroiliac joint MR Imaging at 3 Tesla: Impact of coil design and motion resistant sequences on image quality.

To evaluate the impact of coil design and motion-resistant sequences on the quality of sacroiliac magnetic resonance imaging (MRI) examination in patients with spondyloarthropathy. One hundred and twenty-one patients with suspected sacroiliitis and referred for MRI of the sacroiliac joints were retrospectively evaluated with MRI at 3-Tesla. There were 78 women and 43 men with a mean age of 36.7±11.5 (SD) years (range: 15.8-78.4 years). Conventional and motion-resistant fat-saturated fast-spin echo T2-weighted sequences were performed with two different coils. Image quality was subjectively evaluated by two independent readers (R1 and R2) using a four-point scale. Confidence in the identification of bone marrow edema pattern (BMEP) was also evaluated subjectively using a three-point scale. Phased array body coil yielded improved image quality compared to surface coil (14.1 to 30.4% for R1 and 14.6 to 25.7% for R2; P<0.0001). The impact of the sequence type on quality was also statistically significant (P=0.0046). BMEP was identified in 40 patients and best inter-reader agreement was obtained using the combination of phased-array body coil with motion-resistant T2-weighted sequence (kappa 0.990). The smallest number of indeterminate BMEP zones was seen on MRI set acquired with the phased-array body coil and motion-resistant T2-weighted sequence. Phased array body coil and motion-resistant T2-weighted sequences perform better than surface coil and conventional T2-weighted sequences for the evaluation of sacroiliac joints, increasing confidence in the identification of BMEP.

MR diffusion imaging in mediastinal masses the differentiation between benign and malignant lesions

BackgroundDiffusion-weighted imaging is a fundamental tool integrated in MR protocols useful in differentiating benign from malignant mediastinal masses, assessing mediastinal lymphadenopathy and investigating central bronchogenic carcinoma. This method is an excellent alternative to CT or PET/CT in the investigation of mediastinal masses. Current applications of diffusion MRI in malignancies include monitoring the treatment response and detecting recurrent cancer. Aim of the workThis study aims to assess the value of using MRI diffusion in differentiating benign and malignant mediastinal masses, differentiating central masses from post obstructive collapse and differentiating lymphoma versus sarcoidosis. Patients and methodsThis study included 30 patients; 16 males and 14 females in the period from June 2013 to July 2014. The mean age was 49.3±16.85 (range: 22–82years).Cases were referred for MRI assessment and were approved by the ethical committee in our department.The complaints varied between dyspnea, chest pain, cough, hemoptysis, fatigue and loss of weight. A superconducting 1.5T MRI machine with a four-channel body phased-array coil was used for the examination. Biopsy and histopathological assessment was done after that. ResultsMRI examination with diffusion imaging was able to differentiate between benign and malignant mediastinal and hilar lesion confirmed by the biopsy and histopathology. ConclusionMRI with diffusion weighted images can detect and stage lung cancer, differentiate benign from malignant mediastinal masses and differentiate lymphoma from sarcoidosis in mediastinal/hilar lymphadenopathy.

Multiparametric MRI of the prostate with three functional techniques in patients with PSA elevation before initial TRUS-guided biopsy.

Multiparametric MRI (mp-MRI) of the prostate is increasingly being used for local staging and detection of recurrence of prostate cancer (PCA). In patients with elevated prostate-specific antigen (PSA), mp-MRI could provide information on the position of the cancer, allowing adjustments to be made to the needle depth and direction before repeat transrectal ultrasound (TRUS)-guided biopsy to ensure accurate sampling of lesions. The purpose of the prospective study was to evaluate mp-MRI of the prostate in patients with PSA elevation before initial TRUS-guided biopsy. mp-MRI was performed in 94 patients using a 1.5-T scanner (MAGNETOM Aera(®); Siemens Healthcare, Erlangen, Germany) and 16-channel phased-array body coil (Siemens Healthcare). T2 weighted images (T2WI), diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI and MR spectroscopy were obtained. TRUS-guided random biopsies and additional targeted biopsies of suspicious MRI areas were performed. Additional targeted biopsies were obtained in 17 of 43 (40%) patients with PCA. 11 of 17 targeted biopsies contained PCA. 5 of 11 PCAs were diagnosed only by additional targeted biopsies. Sensitivity of mp-MRI in patients was 97.7% and specificity was 11.8%. mp-MRI was false negative in one patient. Sensitivity of mp-MRI in 207 lesions was 80.9% and specificity was 44.7%. In a logistic regression model, the apparent diffusion coefficient value was the only significant parameter to differentiate malignant and benign lesions. mp-MRI should be performed in patients with PSA elevation before initial TRUS-guided biopsy to allow additional targeted biopsies from suspicious areas of MRI. We recommend mp-MRI with T2WI, DWI, DCE MRI and MR spectroscopy. DWI as the most reliable technique should be used in every mp-MRI. DWI is the most reliable technique in mp-MRI of the prostate.

Fusion imaging for evaluation of deep infiltrating endometriosis: feasibility and preliminary results.

Magnetic resonance imaging (MRI) and ultrasound scanning complement each other in screening for and diagnosis of endometriosis. Fusion imaging, also known as real-time virtual sonography, is a new technique that uses magnetic navigation and computer software for the synchronized display of real-time ultrasound and multiplanar reconstructed MR images. Our aim was to evaluate the feasibility and ability of fusion imaging to assess the main anatomical sites of deep infiltrating endometriosis (DIE) in patients with suspected active endometriosis. This prospective study was conducted over a 1-month period in patients referred to a trained radiologist for an ultrasound-based evaluation for endometriosis. Patients with a prior pelvic MRI examination within the past year were offered fusion imaging, in addition to the standard evaluation. All MRI examinations were performed on a 1.5-T MRI machine equipped with a body phased-array coil. The MRI protocol included acquisition of at least two fast spin-echo T2-weighted orthogonal planes. The Digital Imaging Communications in Medicine dataset acquired at the time of the MRI examination was loaded into the fusion system and displayed together with the ultrasound image on the same monitor. The sets of images were then synchronized manually using one plane and one anatomical reference point. The ability of this combined image to identify and assess the main anatomical sites of pelvic endometriosis (uterosacral ligaments, posterior vaginal fornix, rectum, ureters and bladder) was evaluated and compared with that of standard B-mode ultrasound and MRI. Over the study period, 100 patients were referred for ultrasound examination because of endometriosis. Among them were 20 patients (median age, 35 (range, 27-49) years) who had undergone MRI examination within the past year, with a median (range) time interval between MRI and ultrasound examination of 171 (1-350) days. All 20 patients consented to undergo additional evaluation by fusion imaging. However, in three (15%) cases, fusion imaging was not technically possible because of changes since the initial MRI examination resulting from either interval surgery (n = 2; 10%) or pregnancy (n = 1; 5%). Data acquisition, matching and fusion imaging were performed in under 10 min in each of the other 17 cases. The overall ability of each technique to identify and assess the main anatomical landmarks of endometriosis was as follows: uterosacral ligaments: ultrasound, 88% (30/34); MRI, 100% (34/34); fusion imaging, 100% (34/34); posterior vaginal fornix: ultrasound, 88% (30/34); MRI, 100% (34/34); fusion imaging, 100% (34/34); rectum: ultrasound, 100% (17/17); MRI, 82.3% (14/17); fusion imaging, 100% (17/17); ureters: ultrasound, 0%; MRI, 100% (34/34); fusion imaging, 100% (34/34); and bladder: ultrasound, 100%; MRI, 100%; fusion imaging, 100%. Fusion imaging is feasible for the assessment of endometriotic lesions. Because it combines information from both ultrasound and MRI techniques, fusion imaging allows better identification of the main anatomical sites of DIE and has the potential to improve the performance of ultrasound and MRI examination.