Diagnostic Value of High-Resolution Ultrasound for the Evaluation of Capsular Width in Temporomandibular Joint Effusion.

Aim: The aim of this study was to evaluate if the increased temporomandibular joint (TMJ) capsular thickness, measured by ultrasound (US), is associated with the presence of effusion, diagnosed using MRI imaging. Materials and Methods: 102 patients with signs and symptoms of temporomandibular disorders were included in the study. Each patient underwent US and MRI examinations, 1 to 5 days following clinical examination. The US was performed with an 8−40 MHz linear transducer operating at 20 MHz. The MRI was performed using a 1.5 T MRI device. The ROC curve was analyzed to identify the optimal cut-off value for capsular distention, which can be interpreted as an indirect sign of TMJ effusion. Results: The capsular width values were found to be between 0.7 and 3.6 mm. The best cut-off value was 2.05 mm with a sensitivity of 55.9% and a specificity of 94.7%. The next optimal cut-off value was 1.75 mm with a sensitivity of 67.6% and a specificity of 82.4%. The area under the ROC curve was 0.78 (95% CI 0.68, 0.87, p < 0.05). Conclusions: Ultrasound-measured capsular width can be interpreted as an indirect sign of TMJ effusion. The critical cut-off for capsular width was 2 mm.

Diagnostic use of computerized axiography in TMJ disc displacements.

Application of paraclinical methods for investigating the temporomandibular joint (TMJ) has been a subject of constant controversy due to the absence of universally-accepted criteria and lack of consensus regarding their usage. Compared with medical imaging, which provides a structural analysis of the TMJ, axiography involves the functional recording of condylar movements. The aim of the present study was to explore the diagnostic value of computerized axiography for TMJ disc displacements using MRI as the reference standard. The present study included 33 (66 TMJs) patients clinically diagnosed with TMJ disc displacements. On the same day, all patients underwent clinical examination and computerized axiography measurements using Cadiax Compact® II before undergoing MRI (1.5 T) 1-7 days later. The characteristics of the diagnostic parameters, namely sensitivity, specificity, positive and negative predictive values, accuracy, Youden index and the 95% confidence intervals (CI), were all computed. Compared with MRI, computerized axiography yielded a sensitivity of 85.11%, specificity of 94.74%, positive predictive value of 97.56%, negative predictive value of 72% and a diagnostic accuracy of 87.88% for any disc displacements. This suggests that computerized axiography can confer high sensitivity, specificity and accuracy for the diagnosis of TMJ disc displacements. However, axiographic analysis has no diagnostic significance in TMJ function if not associated with clinical examination.

Acute dental malocclusion associated with lateral pterygoid muscle partial tear: Case Report and literature review.

BACKGROUND: The article presents a rare case of acute malocclusion produced by a unilateral partial tear of the lateral pterygoid muscle and an up-to-date literature review of the pathology. CLINICAL PRESENTATION: A 37-year-old female was examined; her chief complaints were pain on the right side of the temporomandibular joint (TMJ) area and mastication impairment associated with major occlusal modifications and anterior open bite. After magnetic resonance imaging (MRI) and cone beam computed tomography (CBCT) of the TMJ and subsequent MRI for soft tissue, the final diagnosis was a partial right lateral pterygoid muscle tear. CONCLUSION: The case shows the value of combined imaging in temporomandibular disorders (TMD) and the importance of soft tissue evaluation in addition to articular examination, as the primary pathology might lie outside the joint. The authors' review of the current literature did not hitherto reveal a similar case.

High-resolution ultrasound imaging compared to magnetic resonance imaging for temporomandibular joint disorders: An in vivo study.

PURPOSE: The study aims to determine the diagnostic value of high-resolution ultrasonography (US) compared with magnetic resonance imaging (MRI) for the evaluation of temporomandibular disorders (TMD). METHODS: Fifty consecutive patients (42 female and 8 male) with signs and symptoms of TMD according to the Research Diagnostic Criteria for TMD were enrolled in the study. Each patient underwent US (13 and 20 MHz) and MRI examination of both TMJs, 1-7 days following clinical examination. All MRI examinations were performed by another radiologist using an 1.5 T MRI device. Sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV, NPV) and diagnostic accuracy were computed along with 95% confidence intervals. RESULTS: For overall disc displacements, 13 MHz US showed a Se of 72.58%, Sp of 86.84%, PPV of 90%, NPV of 66% and diagnostic accuracy of 78%, while 20 MHz US showed a Se of 75.81%, Sp of 86.84%, PPV of 90.38%, NPV of 68.75% and a diagnostic accuracy of 80%. For degenerative changes, 13 MHz US revealed a Se of 58.33%, Sp of 92.11%, PPV of 70%, NPV of 87.5% and a diagnostic accuracy of 84%, whereas 20 MHz US indicated the same Se of 58.33%, Sp of 93.42%, PPV of 73.68%, NPV of 87.65% and a diagnostic accuracy of 85%. The Cohen's Kappa coefficient for the intra- and inter-observer agreement was 0.822 and 0.836 for disc displacement, respectively 0.813 and 0.788 for degenerative disorders (p < 0.001). CONCLUSIONS: High-resolution US could be a useful imaging technique in diagnosing TMJ disc displacements.

Local staging of prostate cancer with multiparametric-MRI: accuracy and inter-reader agreement.

BACKGROUND: The accuracy of prostate cancer local staging at the time of diagnosis directly influences patient prognosis and treatment. AIM: To evaluate the diagnostic performance and interobserver variability of mp-MRI in local staging of prostate cancer, using the histopathologic findings at prostatectomy as the reference standard. METHODS: Fifty patients (mean age 64.4±7.2) with biopsy confirmed prostate cancer were included in this prospective study. All patients were examined with mp-MRI before radical prostatectomy and images were read by three independent radiologists. Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy rate were calculated and compared for all three readers. Interobserver agreement was evaluated using Kappa Cohen coefficient of agreement. RESULTS: The overall Se, Sp, PPV, NPV and accuracy rates for detecting extraprostatic tumor extension (EPE) ranged between 76.5-94.1%, 45.5-84.9%, 43.8-76.2%, 83.3-96.6% and 58-88%. For evaluation of seminal vesicle invasion (SVI), the overall Se, Sp, PPV, NPV and accuracy rates ranged between 57.1-85.7%, 86.1-97.7%, 40.0-85.7%, 92.5-97.7% and 82-96%, respectively. The overall Kappa Cohen coefficient of agreement varied between 0.349-0.638 for EPE and between 0.507-0.668 for SVI. CONCLUSIONS: Our results showed that 1.5T mp-MRI is a reliable method for local staging of prostate cancer, with good diagnostic performance in detecting EPE and SVI. The overall interobserver agreement rates between readers with the same level of experience in prostate MRI ranged from fair to good in the evaluation of EPE and from moderate to good for the assessment of SVI.

Imaging modalities for temporomandibular joint disorders: an update.

The diagnosis and management of temporomandibular disorders (TMD) require both clinical and imaging examinations of the temporomandibular joint (TMJ). A variety of modalities can be used to image the TMJ, including magnetic resonance imaging (MRI), computed tomography (CT), cone beam CT, ultrasonography, conventional radiography. The present review outlines the indications of the most frequently used imaging techniques in TMD diagnosis. Because of the anatomic complexity of the TMJ, imaging can be difficult. Choosing the proper imaging technique is essential. Conventional radiography, nowadays, is of limited interest. The use of flat plane films for TMJ pathology is not sufficient, because this joint requires three dimensional imaging views. Osseous changes are better visualized with CT and cone beam CT. Cone beam CT provides high-resolution multiplanar reconstruction of the TMJ, with a low radiation dose, without superimposition of the bony structures. MRI is a noninvasive technique, considered to be the gold standard in imaging the soft tissue components of the TMJ. MRI is used to evaluate the articular disc in terms of location and morphology. Moreover, the early signs of TMD and the presence of joint effusion can be determined. High-resolution ultrasonography is a noninvasive, dynamic, inexpensive imaging technique, which can be useful in diagnosing TMJ disc displacements. The diagnostic value of high-resolution ultrasonography is strictly dependent on the examiner's skills and on the equipment used.

Getting Started with Magnetic Resonance Neurography.

This article provides a review of magnetic resonance neurography (MRN) and how to get started. It explains step by step how to establish MRN at an institution: how to set up MRN protocols, how to train technicians, what a report needs to contain, and how relevant findings should be communicated to the referring physician. Advanced imaging techniques such as diffusion tensor imaging are only briefly discussed at the end of the article because most of those techniques are difficult for beginners and are still not considered standard in the clinical routine.

Correlation of listhesis on upright radiographs and central lumbar spinal canal stenosis on supine MRI: is it possible to predict lumbar spinal canal stenosis?

OBJECTIVE: To investigate whether upright radiographs can predict lumbar spinal canal stenosis using supine lumbar magnetic resonance imaging (MRI) and to investigate the detection performance for spondylolisthesis on upright radiographs compared with supine MRI in patients with suspected lumbar spinal canal stenosis (LSS). MATERIALS AND METHODS: In this retrospective study, conventional radiographs and MR images of 143 consecutive patients with suspected LSS (75 female, mean age 72 years) were evaluated. The presence and extent of listhesis (median ± interquartile range) were assessed on upright radiographs and supine MRI of L4/5. In addition, the grade of central spinal stenosis of the same level was evaluated on MRI according to the classification of Schizas and correlated with the severity/grading of anterolisthesis on radiographs. RESULTS: Anterolisthesis was detected in significantly more patients on radiographs (n = 54; 38%) compared with MRI (n = 28; 20%), p < 0.001. Pairwise comparison demonstrated a significantly larger extent of anterolisthesis on radiographs (9 ± 5 mm) compared with MRI (5 ± 3 mm), p < 0.001. A positive correlation was found regarding the extent of anterolisthesis measured on radiographs and the grade of stenosis on MRI (r = 0.563, p < 0.001). Applying a cutoff value of ≥5 mm anterolisthesis on radiographs results in a specificity of 90% and a positive predictive value of 78% for the detection of patients with LSS, as defined by the Schizas classification. CONCLUSION: Upright radiographs demonstrated more and larger extents of anterolisthesis compared with supine MRI. In addition, in patients with suspected LSS, the extent of anterolisthesis on radiographs (particularly ≥5 mm) is indicative of LSS and warrants lumbar spine MRI.

High-resolution ultrasonography in assessing temporomandibular joint disc position.

AIMS: The purpose of this study was to determine the diagnostic value of high-resolution ultrasonography (US) in temporomandibular joint (TMJ) disc displacements. MATERIALS AND METHODS: A number of 74 patients (148 TMJs) with signs and symptoms of TMJ disorders, according to the Research Diagnostic Criteria for Temporomandibular Disorders, were included in this study. All patients received US and magnetic resonance imaging (MRI) of both TMJs 1 to 5 days after the clinical examination. MRI examinations were performed using 1.5 T MRI equipment (Siemens Avanto, Siemens, Erlangen). Ultrasonographic examination was performed on a Hitachi EUB 8500 (Hitachi Medical Corp., Tokyo, Japan) scanner with L 54 M6.5-13 MHz linear transducer. RESULTS: MRI depicted 68 (45.95%) normal joints, 47 (31.76%) with disc displacement with reduction, 33 (22.3%) with disc displacement without reduction and 34 (22.97%) with degenerative changes. US detected 78 (52.7%) normal joints, 37 (25%) with disc displacement with reduction, 33 (22.3%) with disc displacement without reduction and 21 (14.19%) with degenerative changes. Compared to MRI, US showed a sensitivity of 93.1%, specificity of 87.88%, accuracy of 90.32%, a positive predictive value of 87.1% and a negative predictive value of 93.55% for overall diagnosis of disc displacement. The Youden index was 0.81. CONCLUSIONS: Based on our results, high-resolution ultrasonography showed high sensitivity, specificity and accuracy in the diagnosis of TMJ disc displacement. It could be a valuable imaging technique in assessing TMJ disc position. The diagnostic value of high-resolution ultrasonography depends strictly on the examiner's skills and on the equipment used.

Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences.

PURPOSE: To assess the performance of fat-suppressed fluid-sensitive MRI sequences compared to T1-weighted (T1w) / T2w sequences for the detection of Modic 1 end-plate changes on lumbar spine MRI. MATERIALS AND METHODS: Sagittal T1w, T2w, and fat-suppressed fluid-sensitive MRI images of 100 consecutive patients (consequently 500 vertebral segments; 52 female, mean age 74 ±â€Š7.4 years; 48 male, mean age 71 ±â€Š6.3 years) were retrospectively evaluated. We recorded the presence (yes/no) and extension (i. e., Likert-scale of height, volume, and end-plate extension) of Modic I changes in T1w/T2w sequences and compared the results to fat-suppressed fluid-sensitive sequences (McNemar/Wilcoxon-signed-rank test). RESULTS: Fat-suppressed fluid-sensitive sequences revealed significantly more Modic I changes compared to T1w/T2w sequences (156 vs. 93 segments, respectively; p < 0.001). The extension of Modic I changes in fat-suppressed fluid-sensitive sequences was significantly larger compared to T1w/T2w sequences (height: 2.53 ±â€Š0.82 vs. 2.27 ±â€Š0.79, volume: 2.35 ±â€Š0.76 vs. 2.1 ±â€Š0.65, end-plate: 2.46 ±â€Š0.76 vs. 2.19 ±â€Š0.81), (p < 0.05). Modic I changes that were only visible in fat-suppressed fluid-sensitive sequences but not in T1w/T2w sequences were significantly smaller compared to Modic I changes that were also visible in T1w/T2w sequences (p < 0.05). CONCLUSION: In conclusion, fat-suppressed fluid-sensitive MRI sequences revealed significantly more Modic I end-plate changes and demonstrated a greater extent compared to standard T1w/T2w imaging. KEY POINTS: · When the Modic classification was defined in 1988, T2w sequences were heavily T2-weighted and thus virtually fat-suppressed.. · Nowadays, the bright fat signal in T2w images masks edema-like changes.. · The conventional definition of Modic I changes is not fully applicable anymore.. · Fat-suppressed fluid-sensitive MRI sequences revealed more/greater extent of Modic I changes.. CITATION FORMAT: · Finkenstaedt T, Del Grande F, Bolog N et al. Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences. Fortschr Röntgenstr 2018; 190: 152 - 160.

Degenerative lumbar spinal canal stenosis: intra- and inter-reader agreement for magnetic resonance imaging parameters.

PURPOSE: To assess the inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of degenerative lumbar spinal canal stenosis (LSS) by magnetic resonance imaging (MRI). METHODS: In this ethical board approved cross-sectional multicenter study, MRI of 100 randomly selected patients (median age 72.5 years, 48 % female) of the prospective Lumbar Stenosis Outcome Study (LSOS) were evaluated by two independent readers. A set of five previously published core imaging parameters as well as nine qualitative and five quantitative additional parameters regarding LSS and degenerative changes of the lumbar spine were assessed to calculate κ and intraclass correlation coefficients (ICC) for the inter-reader agreement. Additional repeated image evaluations were performed by one reader to calculate the intra-reader agreement. RESULTS: κ values for the core image parameters ranged between 0.42 (compromise of the foraminal zone) and 0.77 (relation between fluid and cauda equina) for inter-reader agreement and between 0.59 (compromise of the foraminal zone) and 0.8 (compromise of the central zone) for intra-reader agreement. The inter-reader agreement for the non-core parameters showed κ values of 0.27-0.69 and ICC values of 0.46-0.85. The intra-reader agreement showed κ values of 0.53-0.69 and ICC values of 0.81-0.88. CONCLUSIONS: The inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of LSS showed quite a variability with previously defined core parameters having good to excellent inter- and intra-reader agreements.

Contrast enhanced ultrasonography in assessing the treatment response to transarterial chemoembolization in patients with hepatocellular carcinoma.

The last decades have known continuous development of therapeutic strategies in hepatocellular carcinoma (HCC). Unfortunately the disease it still not diagnosed until it is already at an intermediate or even an advanced disease. In these circumstances transarterial chemoembolization (TACE) is considered an effective treatment for HCC. The most important independent prognostic factor of both disease free survival and overall survival is the presence of complete necrosis. Therefore, treatment outcomes are dictated by the proper use of radiological imaging. Current guidelines recommend contrast enhanced computer tomography (CECT) as the standard imaging technique for evaluating the therapeutic response in patients with HCC after TACE. One of the most important disadvantage of CECT is the overestimation of tumor response. As an attempt to overcome this limitation contrast enhanced ultrasound (CEUS) has gained particular attention as an imaging modality in HCC patients after TACE. Of all available imaging modalities, CEUS performs better in the early and very early assessment of TACE especially after lipiodol TACE. As any other imaging techniques CEUS has disadvantages especially in hypovascular tumors or in cases of tumor multiplicity. Not far from now the current limitations of CEUS will be overcome by the new CEUS techniques that are already tested in clinical practice such as dynamic CEUS with quantification, three-dimensional CEUS or fusion techniques.

Reporting knee meniscal tears: technical aspects, typical pitfalls and how to avoid them.

UNLABELLED: Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. An accurate interpretation of the knee depends on several factors, starting with technical aspects including radiofrequency coils, imaging protocol and magnetic field strength. The use of dedicated high-resolution orthopaedic coils with a different number of integrated elements is mandatory in order to ensure high homogeneity of the signal and high-resolution images. The clinical imaging protocol of the knee includes different MRI sequences with high-spatial resolution in all orientations: sagittal, coronal, and axial. Usually, the slice thickness is 3 mm or less, even with standard two-dimensional fast spin echo sequences. A common potential reason for pitfalls and errors of interpretation is the unawareness of the normal tibial attachments and capsular attachment of the menisci. Complete description of meniscal tears implies that the radiologist should be aware of the patterns and the complex classification of the lesions. TEACHING POINTS: • Technical factors may influence MRI interpretation. • Unawareness of the normal meniscal anatomy may lead to errors of interpretation. • Description of meniscal tears implies the knowledge of meniscal tear classification.

CT and MR imaging of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most common tumor in the world and the incidence is expected to increase in the future due to hepatitis viral infections and increasing cirrhosis incidence. The diagnosis of HCC is no longer based on biopsy especially in cases when curative treatment is possible. The imaging criteria are usually based on the vascular findings of HCC (e.g. early arterial uptake followed by washout in the portovenous and equilibrium phase). However, there are several limitations of the assessment of HCC by using only the vascular criteria. The use of tissue-specific contrast agents, including superparamagnetic iron oxides and hepatobiliary contrast agents, improves lesion detection and characterization. Therefore, an accurate diagnosis of HCC implies, at this moment, a combination of vascular and cellular information. This review focuses on the most important findings provided by the unenhanced and dynamic-enhanced CT and MR images regarding HCC evaluation. We also discuss the various imaging characteristics of HCC at MR imaging after the administration of tissue specific contrast agents.

Focal liver lesions: detection and characterization at double-contrast liver MR Imaging with ferucarbotran and gadobutrol versus single-contrast liver MR imaging.

PURPOSE: To retrospectively compare, in a multiobserver study, double-contrast-material (sequential administration of ferucarbotran and gadobutrol) magnetic resonance (MR) imaging with single-contrast-material ferucarbotran-enhanced and dynamic postferucarbotran gadobutrol-enhanced MR imaging for the detection and characterization of benign and malignant focal liver lesions. MATERIALS AND METHODS: This study was institutional review board approved, and the requirement for informed patient consent was waived. Eighty-nine patients with a total of 128 focal liver lesions underwent double-contrast liver MR imaging (nonenhanced, ferucarbotran-enhanced, and dynamic postferucarbotran gadobutrol-enhanced MR imaging performed during one session). Four readers independently reviewed the data sets during three reading sessions focused on focal liver lesion detection and characterization: In session 1, the nonenhanced and dynamic postferucarbotran gadobutrol-enhanced images obtained at double-contrast MR imaging were analyzed. In session 2, the nonenhanced and ferucarbotran-enhanced images were analyzed. In session 3, all MR images were analyzed together. The diagnostic performance of each MR technique and each reader was evaluated by using receiver operating characteristic (ROC) analysis; differences between postferucarbotran gadobutrol-enhanced, ferucarbotran-enhanced, and double-contrast MR imaging were assessed at Wilcoxon signed rank testing; and interreader agreement was assessed at Cohen kappa analysis. Histopathologic confirmation or an unchanged clinical course or MR finding was the reference standard. RESULTS: The four readers' detection of the benign and malignant lesions was not significantly different (P > or = .11) between the three MR techniques. The benign and malignant focal liver lesions were differentiated with significantly higher confidence (P < or = .01) on the double-contrast (area under ROC curve [A(z)] = 0.988) and ferucarbotran-enhanced (A(z) = 0.985) MR images than on the dynamic gadobutrol-enhanced images (A(z) = 0.963). Accuracy in the diagnosis of hepatocellular carcinoma (HCC) was highest (P = .02) and confidence in the final diagnosis of HCC (P = .001) or metastasis (P = .049) was significantly higher with double-contrast imaging. CONCLUSION: In select cases, double-contrast MR imaging can improve diagnostic accuracy and increase confidence in characterizing focal liver lesions as HCC or metastasis.

Double-contrast magnetic resonance imaging of hepatocellular carcinoma after transarterial chemoembolization.

BACKGROUND: The purpose of this study was to assess the accuracy of double-contrast magnetic resonance (MR) imaging for the treatment response evaluation of hepatocellular carcinoma (HCC) in cirrhotic liver after transarterial chemoembolization (TACE). METHODS: Twenty-two patients with 30 HCC nodules treated by TACE underwent double-contrast MR imaging 1 month after treatment. MR images were obtained before and after the sequential administration of superparamagnetic iron oxide (SPIO) and gadopentetate dimeglumine contrast agent within the same imaging session. Two observers retrospectively assessed all treated nodules for evidence of residual viable tumor after TACE. The diagnostic performance of gadolinium-enhanced, SPIO-enhanced, and double-contrast enhanced images was calculated. Histopathological and angiographical findings served as standard of reference. Receiver operating characteristic curves and areas under the curves (A (z)) were calculated. RESULTS: Double-contrast technique (A (z) = 0.95) was significantly (p = 0.036) more accurate than SPIO-enhanced technique (A (z) = 0.92) and gadolinium-enhanced technique (p = 0.005) (A (z) = 0.81) in viable tumor detection after TACE. Double-contrast technique was significantly more sensitive (92%) than SPIO-enhanced technique (80%) and gadolinium-enhanced technique (68%). Kappa values for interobserver agreement ranged from 0.67 to 0.87 and were significantly different from zero (all p < 0.001). CONCLUSIONS: Compared to gadolinium-enhanced and SPIO-enhanced techniques, double-contrast technique significantly improves the detection of viable tumor in HCC after TACE.

MR imaging of the posterolateral corner of the knee.

The posterolateral corner (PLC) is a complex functional unit, consisting of several structures, which is responsible for posterolateral stabilization. The PLC is not consistently defined in the literature. However, most descriptions include the popliteal tendon (PT), the lateral collateral ligament (LCL), the popliteofibular ligament (PFL) and the posterolateral capsule, which is reinforced by the arcuate ligament (AL) and the fabellofibular ligament (FFL). Knowledge of PLC anatomy, including its variations, and understanding of the biomechanics is important for correct diagnosis of PLC injuries. An overlooked PLC injury can result in chronic instability, chronic pain, and, eventually, in secondary osteoarthritis. Damage to the PLC also has an adverse effect on the outcome of cruciate ligament repair. Isolated lesions of the PLC are rare. PLC lesions are typically associated with injuries of the cruciate ligaments, the menisci, bone and soft tissue. In the acute phase, clinical findings can be difficult to interpret due to pain and swelling. Magnetic resonance (MR) imaging potentially demonstrates the entire spectrum of PLC injuries and associated lesions of the knee, including those that may be overlooked during clinical examination or arthroscopy.

Muskuloskeletal MR imaging at 3.0 T: current status and future perspectives.

Magnetic resonance (MR) imaging has become an important diagnostic tool in evaluation of the musculoskeletal system. While most examinations are currently performed at magnetic field strengths of 1.5 T or lower, whole-body MR systems operating at 3.0 T have recently become available for clinical use. The higher field strengths promise various benefits, including increased signal-to-noise ratios, enhanced T2* contrast, increased chemical shift resolution, and most likely a better diagnostic performance in various applications. However, the changed T1, T2, and T2* relaxation times, the increased resonance-frequency differences caused by susceptibility and chemical-shift differences, and the increased absorption of radiofrequency (RF) energy by the tissues pose new challenges and/or offer new opportunities for imaging at 3.0 T compared to 1.5 T. Some of these issues have been successfully addressed only in the very recent past. This review discusses technical aspects of 3.0 T imaging as far as they have an impact on clinical routine. An overview of the current data is presented, with a focus on areas where 3.0 T promises equivalent or improved performance compared 1.5 T or lower field strengths.

Dynamic MR imaging of outlet obstruction.

The outlet obstruction syndrome encompasses all pelvic floor abnormalities which are responsible for an incomplete evacuation of fecal contents from the rectum. It has been estimated that outlet obstruction may be observed in half of constipated patients. A detailed clinical examination still represents the cornerstone of the diagnosis of these patients. However, there is general agreement that a reliable evaluation of the different pelvic floor abnormalities and the treatment decision highly depend on the imaging assessment. Traditionally, conventional defecography has played an important role in the radiological assessment of these patients but the technique is limited by its projectional nature and its inability to detect soft-tissue structures. Dynamic pelvic MR imaging using either closed-configuration or open-configuration MR systems is a rapidly evolving technique which has been gaining increased interest over the last years. The free selection of imaging planes, the good temporal resolution, and the excellent soft-tissue contrast have transformed this method into the preferred imaging modality in the evaluation of patients with pelvic floor dysfunction including rectocele, enterocele, internal rectal prolapse, and anismus.

Magnetic resonance imaging of bile and pancreatic ducts: a retrospective study.

PURPOSE: To assess the value of magnetic resonance in the diagnosis of pancreatobiliary ductal system changes. MATERIAL AND METHODS: The study included 103 patients (44 men, 59 women, mean age 57, age range 1 month - 91 years) with pancreatobiliary duct changes. The patients underwent a routine liver and pancreas MR imaging that included a MR cholangiopancreatography sequence. Comparison was made with findings at surgery, endoscopic retrograde cholangiopacreatography performed within 14 days, and follow-up, as a reference standard. RESULTS: The sensitivity, specificity, and accuracy of magnetic resonance for the evaluation of lithiasis were 87%, 90.2% and 89.3% respectively; 100%, 97.8%, and 98%, respectively for cholangitis; 91.6%, 96.7% and 96,1%, for bile ducts tumors; 89.4%, 97.5%, and 96%, for chronic pancreatitis; 92.3%, 97.6%, and 96.6%, for pancreatic tumors; 88.8%, 96.4% and 95.1%, for periampullary stenosis. CONCLUSION: Magnetic resonance is a reliable imaging technique for the evaluation of biliary and pancreatic ducts