Static and dynamic evaluation of pelvic floor disorders with an open low-field tilting magnet.

AIM: To assess the feasibility of magnetic resonance defaecography (MRD) in pelvic floor disorders using an open tilting magnet with a 0.25 T static field and to compare the results obtained from the same patient both in supine and orthostatic positions. MATERIALS AND METHODS: From May 2010 to November 2011, 49 symptomatic female subjects (mean age 43.5 years) were enrolled. All the patients underwent MRD in the supine and orthostatic positions using three-dimensional (3D) hybrid contrast-enhanced (HYCE) sequences and dynamic gradient echo (GE) T1-weighted sequences. All the patients underwent conventional defaecography (CD) to correlate both results. Two radiologists evaluated the examinations; inter and intra-observer concordance was measured. The results obtained in the two positions were compared between them and with CD. RESULTS: The comparison between CD and MRD found statistically significant differences in the evaluation of anterior and posterior rectocoele during defaecation in both positions and of rectal prolapse under the pubo-coccygeal line (PCL) during evacuation, only in the supine position (versus MRD orthostatic: rectal prolapse p < 0.0001; anterior rectocoele p < 0.001; posterior rectocoele p = 0.008; versus CD: rectal prolapse p < 0.0001; anterior rectocoele p < 0.001; posterior rectocoele p = 0.01). The value of intra-observer intra-class correlation coefficient (ICC) ranged from good to excellent; the interobserver ICC from moderate to excellent. CONCLUSION: MRD is feasible with an open low-field tilting magnet, and it is more accurate in the orthostatic position than in the supine position to evaluate pelvic floor disorders.

Breast MRI artefacts: evaluation and solutions in 630 consecutive patients.

AIM: To evaluate the problems that may arise in breast magnetic resonance imaging (MRI) related to the presence of artefacts and pitfalls, in order to improve its accuracy, sensitivity, and specificity. MATERIALS AND METHODS: Six hundred and thirty breast MRI examinations performed using a 1.5 T magnet were analysed retrospectively. Each type of artefact that may have affected the correct interpretation of the acquired images was considered and analysed. In particular, the presence of technical artefacts, which are related to patient-dependent factors or to the examination itself, and non-technical artefacts, which are the result of inadequate and incorrect image interpretation occurring in absence of technical issues, were examined. In every case of suspicious findings, doubtful lesions were subjected to histological characterization for appropriate therapeutic planning. In the remainder of cases, patients underwent follow-up for at least 18 months. RESULTS: Artefacts were found in 33% of all examinations, among those 48.6% were caused by movement, 33.6% were due to non-homogeneous or failed fat saturation, 8.7% to incorrect positioning of the patient, 7.2% to metallic artefacts, 1.4% to aliasing, and 0.5% were "zebra artefacts". When the artefact was identified in a sequence, the sequence was performed a second time after corrective measures. No artefacts affected diagnostic interpretation of the obtained images. CONCLUSION: The present study provides a specific and precise review of the most frequent artefacts with a discussion of possible and practical solutions. A highly qualified team is required to perform accurate diagnostic tests and to limit or remove the possibility of misinterpretation.

Optimisation of low-dose CT with adaptive statistical iterative reconstruction in total body examination.

PURPOSE: The aim of this study was to assess the feasibility of low-dose computed tomography (CT) with the adaptive statistical iterative reconstruction (ASIR) algorithm in whole-body imaging with low tube voltage and current. MATERIALS AND METHODS: Twenty-three patients underwent whole-body CT with 40% of ASIR and parameters modulated according to body mass index (BMI). All had previously undergone conventional-dose CT with 100% filtered back projection (FBP). Two radiologists jointly assessed image quality (sharpness, noise, artefacts) and diagnostic quality blinded to the scanning technique. The effective dose and image quality obtained with the ASIR protocol were compared with those obtained with the FBP algorithm. RESULTS: The mean effective dose achieved with ASIR was 15.6 ± 5 mSv versus 21.8 ± 5.3 mSv with the FBP protocol (p<0.0001). Image quality was good in all low-dose CT scans, and diagnostic quality was comparable with or superior to that of conventional-dose CT. CONCLUSIONS: Low-dose CT with the ASIR algorithm is feasible and ensures significant reduction in effective dose.

Dynamic MR defecography with an open-configuration, low-field, tilting MR system in patients with pelvic floor disorders.

PURPOSE: This study was undertaken to explore the capabilities of an open-configuration, low-field, tilting, magnetic resonance (MR) system for investigating pelvic floor disorders and to compare the results obtained with the patient in the semiorthostatic and supine positions. MATERIALS AND METHODS: Eighteen female patients with a diagnosis of pelvic floor disorder (physical examination and conventional defecography) underwent dynamic MR defecography (MRD) with a 0.25-T tilting MR system (G-scan, Esaote). Images were obtained after administration of contrast agent into the rectum, bladder and vagina in both the orthostatic and supine positions. Three-dimensional T2-weighted hybrid contrast-enhanced (HYCE) sequences and dynamic T1-weighted gradient echo (GE) sequences were acquired at rest, during maximal contraction of the anal sphincter, straining and defecation. RESULTS: Good image quality was obtained in 15/18 patients; three presented severe artefacts due to motion, and three had incontinence, which hampered the functional studies. Better anatomical detail was obtained with MRD compared with conventional defecography. Three prolapses were observed in the semiorthostatic position only, and seven were found to be more severe in the orthostatic than in the supine position. CONCLUSIONS: Dynamic MRD with an open-configuration, low-field, tilting MR system is a feasible and promising tool for studying the pelvic floor. Larger series are necessary to assess its real diagnostic value.

A Case of Primary T-Cell Central Nervous System Lymphoma: MR Imaging and MR Spectroscopy Assessment.

Primary central nervous system lymphomas (PCNSLs) are mainly B-cells lymphomas. A risk factor for the development of PCNSL is immunodeficiency, which includes congenital disorders, iatrogenic immunosuppression, and HIV. The clinical course is rapidly fatal; these patients usually present signs of increased intracranial pressure, nausea, papilledema, vomiting, and neurological and neuropsychiatric symptoms. PCNSL may have a characteristic appearance on CT and MR imaging. DWI sequences and MR spectroscopy may help to differentiate CNS lymphomas from other brain lesions. In this paper, we report a case of a 23-year-old man with T-primary central nervous system lymphoma presenting with a mass in the right frontotemporal lobe. We describe clinical, CT, and MRI findings. Diagnosis was confirmed by stereotactic biopsy of the lesion.