Turbo Inversion Recovery Magnitude Research Articles

Quantitative Measurement of Breast Density Using Personalized 3D-Printed Breast Model for Magnetic Resonance Imaging.

Despite the development and implementation of several MRI techniques for breast density assessments, there is no consensus on the optimal protocol in this regard. This study aimed to determine the most appropriate MRI protocols for the quantitative assessment of breast density using a personalized 3D-printed breast model. The breast model was developed using silicone and peanut oils to simulate the MRI related-characteristics of fibroglandular and adipose breast tissues, and then scanned on a 3T MRI system using non-fat-suppressed and fat-suppressed sequences. Breast volume, fibroglandular tissue volume, and percentage of breast density from these imaging sequences were objectively assessed using Analyze 14.0 software. Finally, the repeated-measures analysis of variance (ANOVA) was performed to examine the differences between the quantitative measurements of breast volume, fibroglandular tissue volume, and percentage of breast density with respect to the corresponding sequences. The volume of fibroglandular tissue and the percentage of breast density were significantly higher in the fat-suppressed sequences than in the non-fat-suppressed sequences (p < 0.05); however, the difference in breast volume was not statistically significant (p = 0.529). Further, a fat-suppressed T2-weighted with turbo inversion recovery magnitude (TIRM) imaging sequence was superior to the non-fat- and fat-suppressed T1- and T2-weighted sequences for the quantitative measurement of breast density due to its ability to represent the exact breast tissue compositions. This study shows that the fat-suppressed sequences tended to be more useful than the non-fat-suppressed sequences for the quantitative measurements of the volume of fibroglandular tissue and the percentage of breast density.

Bone marrow oedema syndrome of the foot and ankle in a paediatric population: a retrospective case series with serial MRI evaluation.

PurposeBy means of a case series we wanted to describe and correlate the clinical and imaging features of bone marrow oedema syndrome (BMOS) of the foot and ankle in children.MethodsA retrospective data study was performed on patients born on or after 01 January 2001 who underwent multiple MRI scans of the foot and ankle for pain symptoms. Six patients who presented with increased signal intensity on T2-weighted MR imaging without any underlying causes or concomitant pathology were included.ResultsAll patients, three boys and three girls with a mean age of 11 years (8 to 14), displayed patchy areas of increased signal intensity on T2-weighted and turbo inversion recovery magnitude (TIRM) images. On average, six tarsal bones were involved (4 to 8). In all patients, treatment consisted of rest and/or protected weight-bearing. The mean time for symptoms to improve during treatment was 6 months (1 to 16). The mean duration of treatment was nine months (3 to 16). In all patients clinical and imaging symptoms were strongly correlated and regressed in time.ConclusionBMOS as a pathological entity should be considered in paediatric patients with foot and ankle pain without a clear underlying cause, and characteristic T2-weighted and TIRM signal intensity increase on MRI images. As BMOS is transient and self-limiting, conservative treatment is advised while the oedema regresses. An early diagnosis of this pathology could prevent unnecessary diagnostic investigations and invasive treatments.Level of EvidenceIV

Appearance of recurrent dermatofibrosarcoma protuberans in postoperative MRI follow-up

Purpose: To analyze the appearance of recurrent dermatofibrosarcoma protuberans (DFSP) in postoperative MRI follow-up and to assess the occurrence of postoperative soft tissue changes detected in MRI.Methods: A total of 464 MRI follow-up scans of 32 patients with histologically proven diagnosis of DFSP were analyzed. MR imaging was performed using a 1.5T MRI system. Recurrent DFSP was examined for signal intensity, contrast behavior, appearance, and extent in MRI.Results: The mean age of the patients was 44,5±17,1 years. Recurrences of DFSP occurred 26±23.3 months after primary tumor resection in the mean (Min.: 9, Max.: 60). In 25% of the patients (n = 8), recurrences of DFSP were detected. Recurrent DFSP most often showed a nodular and homogeneous configuration with well-defined borders and marked contrast enhancement, and a hyperintense signal in PD-weighted and turbo inversion recovery magnitude sequences. All recurrences were well detected in the follow-up MRIs regardless of the performed plastic surgery procedure. Lateral and depth margins had no significant impact on the local recurrence rate. In all, 88% of the patients developed subcutaneous tissue edema (p < 0.01), followed by muscle edema (34%, p = 0.02), and postoperative seroma (22%).Conclusion: Recurrent DFSP mainly appear uniform and clearly delimitable on MRI as nodular, homogeneous, and well-defined lesions with marked contrast enhancement. Therefore, MRI is a valuable tool for postsurgical follow-up. Nearly all patients develop subcutaneous edema after the resection of DFSP.

Skeletal Muscle Involvement in Wilson Disease: Clinical and Magnetic Resonance Imaging (MRI) Observations in 2 Families

Skeletal muscle involvement in Wilson disease is rare. Calf muscle pain might be attributed as growing pain in children. We report calf muscle involvement in Wilson disease and describe the magnetic resonance imaging (MRI) findings of leg, differential diagnosis with literature review. Our observations describe calf muscle MRI abnormality in 5 cases of Wilson disease from 2 families. The clinical presentations were neurologic in 3, hepatic in 1, and asymptomatic in 1 patient. We systematically describe the clinical characteristics and their calf muscle MRI findings. Three patients had bilateral calf pain and intermittent cramps. The pain was of mild to moderate intensity and managed symptomatically. Serum alkaline phosphatase, creatinine phosphokinase, and needle electromyography were normal. Turbo inversion recovery magnitude sequence MRI of calf muscle revealed hyperintensity in bilateral gastrocnemii muscles. These muscles appear hyperintense in diffusion-weighted imaging. The calf muscle involvement could be attributed to muscle edema due to copper-induced muscle toxicity mediated by inhibition of Na+/K+-ATPase on cellular membranes of fast-twitch gastrocnemii muscles which contain predominant type II myofiber. In Wilson disease patients with calf pain or cramps, muscle MRI may show nonspecific gastrocnemius hyperintensity. Further evaluation may give insight into its pathophysiology.

Magnetic resonance imaging reveals distinct bone marrow patterns in indolent and advanced systemic mastocytosis.

Systemic mastocytosis (SM) is broadly subcategorized according to mast cell (MC) burden and organ involvement into indolent (ISM), smoldering (SSM), and advanced SM (AdvSM). However, the pattern and extent of bone involvement remains controversial. In this institutional review board (IRB)-approved study, 115 patients with different forms of SM (ISM (n= 37, 32%), SSM (n= 9, 8%), and AdvSM (n= 69, 60%)) underwent a whole-body magnetic resonance imaging including sagittal and coronal T1 and turbo inversion recovery magnitude (TIRM) sequences of the spine. The evaluation included the pattern and extent of pathologic bone marrow (BM) signals in the spine and extremities, osteolytic lesions, and vertebral fractures. A pathologic BM pattern was observed in 4/37 (11%), 8/9 (89%), and 66/69 (96%); affection of the appendicular skeleton in 3/37 (8%), 8/9 (89%), and 67/69 (97%); and vertebral fractures in 7/37 (19%), 0/9, and 13/69 (19%) patients with ISM, SSM, and AdvSM, respectively. In AdvSM, pathologic BM pattern included activated (62%), diffuse sclerotic (25%), and small-spotted BM (9%), respectively. Only activated/sclerotic BM was associated with significantly higher MC burden, organ damage, and inferior median survival (2.9years, p= 0.04). Vertebral fractures resembled classical multi-segmental osteoporotic fractures in ISM but not in AdvSM in which they were only found in activated/sclerotic BM. Only one patient with AdvSM had a focal osteolytic lesion in the femur. Activated/sclerotic BM changes of the spine and affection of the appendicular skeleton are indicative for SSM or AdvSM. Osteolytic lesions, which are very rare, and osteoporotic fractures are ineligible for the diagnosis of AdvSM.

Non-contrast MRI for breast screening: preliminary study on detectability of benign and malignant lesions in women with dense breasts.

The importance of breast cancer screening has long been known. Unfortunately, there is no imaging modality for screening women with dense breasts that is both sensitive and without concerns regarding potential side effects. The purpose of this study is to explore the possibility of combined diffusion-weighted imaging and turbo inversion recovery magnitude MRI (DWI + TIRM) to overcome the difficulty of detection sensitivity and safety. One hundred and seventy-six breast lesions from 166 women with dense breasts were retrospectively evaluated. The lesion visibility, area under the curve (AUC), sensitivity and specificity of cancer detection by MG, DWI + TIRM, and clinical MRI were evaluated and compared. MG plus clinical MRI served as the gold standard for lesion detection and pathology served as the gold standard for cancer detection. Lesion visibility of DWI + TIRM (96.6%) was significantly superior to MG (67.6%) in women with dense breasts (p < 0.001). There was no significant difference compared with clinical MRI. DWI + TIRM showed higher accuracy (AUC = 0.935) and sensitivity (93.68%) for breast cancer detection than MG (AUC = 0.783, sensitivity = 46.32%), but was comparable to clinical MRI (AUC = 0.944, sensitivity = 93.68%). The specificity of DWI + TIRM (83.95%) was lower than MG (98.77%), but higher than clinical MRI (77.78%). DWI combined with TIRM could be a safe, sensitive, and practical alternative for screening women with dense breasts.

Rheologically Essential Surfactant Proteins of the CSF Interacting with Periventricular White Matter Changes in Hydrocephalus Patients - Implications for CSF Dynamics and the Glymphatic System.

Surfactant proteins (SP) are multi-systemic proteins playing crucial roles in the regulation of rheological properties of physiological fluids, host defense, and the clearance of potentially harmful metabolites. Hydrocephalus patients suffer from disturbed central nervous system (CNS) fluid homeostasis and exhibit remarkably altered SP concentrations within the cerebrospinal fluid (CSF). A connection between CSF-SPs, CSF flow, and ventricular dilatation, a morphological hallmark of hydrocephalus, has been reported previously. However, currently there are no studies investigating the link between rheologically active SPs and periventricular white matter changes caused by impaired CSF microcirculation in hydrocephalic conditions. Thus, the aim of this study was to assess their possible relationships. The present study included 47 individuals (27 healthy subjects and 20 hydrocephalus patients). CSF specimens were analyzed for concentrations of SP-A, SP-C, and SP-D by using enzyme-linked immunosorbent assays (ELISAs). Axial T2w turbo inversion recovery magnitude (TIRM) magnetic resonance imaging was employed in all cases. Using a custom-made MATLAB-based tool for quantification of magnetic resonance signal intensities in the brain, parameters related to disturbed deep white matter CSF microcirculation were estimated (TIRM signal intensity (SI)-mean, minimum, maximum, median, mode, standard deviation, and percentiles, p10th, p25th, p75th, p90th, as well as kurtosis, skewness, and entropy of the SI distribution). Subsequently, statistical analysis was performed (IBM SPSS 24™) to identify differences between hydrocephalic patients and healthy individuals and to further investigate the connections between CSF-SP changes and deep white matter signal intensities. SP-A (0.38 ± 0.23 vs. 0.76 ± 0.49ng/ml) and SP-C (0.54 ± 0.28 vs. 1.27 ± 1.09ng/ml) differed between healthy controls and hydrocephalus patients in a statistically significant manner. Also, corresponding quantification of white matter signal intensities revealed statistically significant differences between hydrocephalus patients and healthy individuals: SImean (370.41 ± 188.15 vs. 222.27 ± 99.86, p = 0.001), SImax (1115.30 ± 700.12 vs. 617.00 ± 459.34, p = 0.005), SImedian (321.40 ± 153.17 vs. 209.52 ± 84.86, p = 0.001), SImode (276.55 ± 125.63 vs. 197.26 ± 78.51, p = 0.011), SIstd (157.09 ± 110.07 vs. 81.71 ± 64.94, p = 0.005), SIp10 (229.10 ± 104.22 vs. 140.00 ± 63.12, p = 0.001), SIp25 (266.95 ± 122.62 vs. 175.63 ± 71.42, p = 0.002), SIp75 (428.80 ± 226.88 vs. 252.19 ± 110.91, p = 0.001), SIp90 (596.47 ± 345.61 vs. 322.06 ± 176.00, p = 0.001), skewness (1.19 ± 0.68 vs. 0.43 ± 1.19, p = 0.014), and entropy (5.36 ± 0.37 vs. 4.92 ± 0.51, p = 0.002). There were no differences regarding SP-D levels in hydrocephalus patients vs. healthy controls. In the acute hydrocephalic subgroup, correlations were as follows: SP-A showed a statistically significant correlation with SImax (r = 0.670, p = 0.024), SIstd (r = 0.697, p = 0.017), SIp90 (r = 0.621, p = 0.041), and inverse correlation with entropy (r = - 0.700, p = 0.016). SP-C correlated inversely with entropy (r = - 0.686, p = 0.020). For the chronic hydrocephalus subgroup, the following correlations were identified: SP-A correlated with kurtosis of the TIRM histogram (r = - 0.746, p = 0.021). SP-C correlated with SImean (r = - 0.688, p = 0.041), SImax (r = - 0.741, p = 0.022), SImedian (r = - 0.716, p = 0.030), SImode (r = - 0.765, p = 0.016), SIstd (r = - 0.671, p = 0.048), SIp25 (r = - 0.740, p = 0.023), SIp75 (r = - 0.672, p = 0.048), and SIp90 (r = - 0.667, p = 0.050). SP-D apparently does not play a major role in CSF fluid physiology. SP-A and SP-C are involved in different aspects of CNS fluid physiology. SP-A appears to play an essential compensatory role in acute hydrocephalus and seems less involved in chronic hydrocephalus. In contrary, SP-C profile and white matter changes are remarkably connected in CSF of chronic hydrocephalus patients. Considering the association between CSF flow phenomena, white matter changes, and SP-C profiles, the latter may especially contribute to the regulation of paravascular glymphatic physiology.

Generative models: an upcoming innovation in musculoskeletal radiology? A preliminary test in spine imaging

BackgroundDeep learning is a ground-breaking technology that is revolutionising many research and industrial fields. Generative models are recently gaining interest. Here, we investigate their potential, namely conditional generative adversarial networks, in the field of magnetic resonance imaging (MRI) of the spine, by performing clinically relevant benchmark cases.MethodsFirst, the enhancement of the resolution of T2-weighted (T2W) images (super-resolution) was tested. Then, automated image-to-image translation was tested in the following tasks: (1) from T1-weighted to T2W images of the lumbar spine and (2) vice versa; (3) from T2W to short time inversion-recovery (STIR) images; (4) from T2W to turbo inversion recovery magnitude (TIRM) images; (5) from sagittal standing x-ray projections to T2W images. Clinical and quantitative assessments of the outputs by means of image quality metrics were performed. The training of the models was performed on MRI and x-ray images from 989 patients.ResultsThe performance of the models was generally positive and promising, but with several limitations. The number of disc protrusions or herniations showed good concordance (κ = 0.691) between native and super-resolution images. Moderate-to-excellent concordance was found when translating T2W to STIR and TIRM images (κ ≥ 0.842 regarding disc degeneration), while the agreement was poor when translating x-ray to T2W images.ConclusionsConditional generative adversarial networks are able to generate perceptually convincing synthetic images of the spine in super-resolution and image-to-image translation tasks. Taking into account the limitations of the study, deep learning-based generative methods showed the potential to be an upcoming innovation in musculoskeletal radiology.

P13. Semi-automatic, machine-learning based segmentation of peripheral nerves for quantitative morphometry: Comparison of low- and high-resolution MR neurography

Background Current state-of-the-art to diagnose peripheral neuropathy are neurological examination and electrodiagnostic studies. However, deeply situated nerves and plexus remain difficult to assess using these techniques, hence magnetic resonance neurography (MRN) emerged as a complementary method. MRN remains a qualitative approach and quantification, in terms of extraction of imaging biomarkers is needed to facilitate diagnosis and for follow-up examinations. Towards a multi-parametric quantitative imaging approach, accurate nerve segmentation needs to be performed first. Hampered by time-consuming manual annotation, we developed a semi-automatic, time-effective, hence clinically feasible segmentation approach based on machine-learning algorithms. In this study, we compared its performance on low- and high-resolution MRN. Materials and methods We acquired images of 9 healthy volunteers at the upper leg using 3 MRN sequences: lower resolution turbo inversion recovery magnitude (TIRM, voxel size of 78 × 78 × 4.0 mm3), lower resolution spin echo T2-weighted (T2, voxel size .52 × .52 × 4.0 mm3), and high resolution, fat-suppressed spin echo T2-weighted (hrT2, voxel size .25 × .25 × 3.3 mm3). An expert manually segmented the sciatic nerve on the T2 and hrT2 images (ground truth, GT). Our segmentation algorithm is based on a decision forest with context- and intensity-based descriptors. We split the images into two sets: a multi-modal low-resolution (TIRM and T2), and a mono-modal high-resolution (hrT2). We perform a leave-one-out cross-validation for both sets and calculate the Dice coefficient to the manually annotated GT. Cross-sectional areas (CSA) were calculated from the middle slice of the image stack. Results Dice coefficients of 0.723 ± 0.202 and 0.735 ± 0.080 are achieved for the low- and high-resolution MRN images (p = 0.858, CI 95 %). Segmentation results and 3-D renderings of the same nerve segmented in low- and high-resolution are shown in Fig. 1 . CSA for GT were 34.0 ± 5.5 mm2 (T2), and 35.4 ± 8.5 mm2 (hrT2), using semi-automatic segmentation 24.8 ± 7.6 mm2 (T2), and 25.7 ± 10.6 mm2 (hrT2). Discussion and conclusion Semi-automatic, hence fast peripheral nerve segmentation is feasible in both low- and high-resolution MRN images of the upper leg, providing image-based quantitative morphometric data. The equal performance of the low-resolution images might be due to the multi-modal setting, which possibly provides more discriminative descriptors for nerve. The lower CSA using semi-automatic segmentation is due to more rigorous segmentation constraints. Future work will include the application of our method to localize and quantify nerve lesions in images of patients diagnosed with peripheral neuropathy.

Elevated Surfactant Protein Levels and Increased Flow of Cerebrospinal Fluid in Cranial Magnetic Resonance Imaging.

Surfactant proteins (SPs) are a multifunctional group of proteins, responsible for the regulation of rheological properties of body fluids, host defense, and cellular waste clearance. Their concentrations are changed in cerebrospinal fluid (CSF) of patients suffering from communicating hydrocephalus. Hydrocephalic conditions are accompanied by altered CSF flow dynamics; however, the association of CSF-SP concentrations and CSF flow has not yet been investigated. Hence, the aim of this study was to evaluate the association between SP concentrations in the CSF and marked CSF flow phenomena at different anatomical landmarks of CSF spaces. Sixty-one individuals (15 healthy subjects and 46 hydrocephalus patients) were included in this study. CSF specimens were analyzed for SP-A, SP-B, SP-C, and SP-D concentrations by the use of enzyme-linked immunosorbent assays (ELISA). CSF flow was evaluated in axial T2_turbo inversion recovery magnitude (TIRM)-weighted and sagittal T2-weighted magnetic resonance imaging sections using a 4-grade scale (1-no flow, 2-subtle flow, 3-moderate flow, and 4-strong flow). CSF-SP concentrations (mean ± standard deviation) of the overall collective were as follows: SP-A = 0.73 ± 0.58ng/ml, SP-B = 0.17 ± 0.93ng/ml, SP-C = 0.95 ± 0.75ng/ml, and SP-D = 7.43 ± 5.17ng/ml. The difference between healthy controls and hydrocephalic patients regarding CSF concentrations of SP-A (0.34 ± 0.22 vs. 0.81 ± 0.59ng/ml) and SP-C (0.48 ± 0.29 vs. 1.10 ± 0.79ng/ml) revealed to be statistically significant as calculated by means of ANOVA (p values of 0.022 and 0.007, respectively). CSF flow voids were detectable at all investigated landmarks of the CSF spaces (foramina of Monro, third ventricle, mesencephalic aqueduct, prepontine cistern, fourth ventricle, cisterna magna, and craniocervical junction). CSF flow voids, reported as mean ± standard deviation, revealed to be significantly increased in hydrocephalic patients compared to controls as calculated by means of ANOVA (respective p values are given in brackets following values of descriptive statistics) at the following sites: foramina of Monro (1.60 ± 0.91 vs. 2.37 ± 0.99, p = 0.01), fourth ventricle (1.67 ± 0.98 vs. 2.52 ± 1.05, p = 0.007), and the cisterna magna (1.93 ± 1.10 vs. 2.72 ± 1.13, p = 0.022). Spearman's rank order calculation identified significant correlations for CSF flow voids at the foramina of Monro and the third ventricle with SP-A (r = 0.429, p = 0.001 and r = 0.464, p < 0.001) and CSF flow void at the mesencephalic duct with SP-D (r = - 0.371, p = 0.039). Furthermore, SP-C showed a moderate inverse correlation with age (r = - 0.302, p = 0.022). The present study confirmed statistically significant differences in SP-CSF concentrations between healthy controls and hydrocephalic patients. Additionally, significant correlations between SP concentrations in CSF with increased CSF flow were identified. These findings underline the role of SPs as regulators of CSF rheology.

Comparisons of slice-encoding metal artifact correction and view-angle tilting magnetic resonance imaging and traditional digital radiography in evaluating chronic hip pain after total hip arthroplasty

PurposeThe aims of this study were (1) to compare the areas of metal-induced artifacts and definition of periprosthetic structures between patients scanned with the slice-encoding metal artifact correction and view-angle tilting (SEMAC-VAT) turbo-spin-echo (TSE) prototype and those scanned with the standard TSE magnetic resonance (MR) sequences and (2) to further clarify the superiority of the SEMAC-VAT MR imaging technique at detecting lesions in patients after total hip arthroplasty (THA), compared with digital radiography (DR). Materials and methodsA total of 38 consecutive patients who underwent THA were referred to MR imaging at our institution. All patients suffered from chronic hip pain postoperatively. Twenty-three patients of the 38 were examined with a 1.5-T MR scanner using a SEMAC-VAT TSE prototype and standard TSE sequence, and the remaining 15 patients were examined with the same 1.5-T MR scanner, but using the SEMAC-VAT TSE prototype only. The traditional DR imaging was also performed for all patients. Two radiologists then independently measured the area of metal-induced artifacts and evaluated the definition of both the acetabular and femoral zones based on a three-point scale. Finally, the positive findings of chronic hip pain after THA based on SEMAC-VAT TSE MR imaging and traditional DR imaging were compared and analysed. ResultsThe areas of metal-induced artifacts were significantly smaller in the SEMAC-VAT TSE sequences than those in the standard TSE sequences for both the T1-weighted (p < 0.001) and T2-weighted (p < 0.001) turbo inversion recovery magnitude images. In addition, 28 patients showed a series of positive signs in the SEMAC-VAT images that were not observed in the traditional DR images. ConclusionCompared with the standard TSE MR imaging, SEMAC-VAT MR imaging significantly reduces metal-induced artifacts and might successfully detect most positive signs missed in the traditional DR images. Translational potential of this articleThe main objective of this research was to show that MR sequences from the SEMAC-VAT TSE prototype provide a significant advantage at detecting lesions in patients after THA because of the excellent soft-tissue resolution of the MR imaging. SEMAC-VAT MR can evaluate chronic hip pain after THA and determine the cause, which can help the clinician decide on whether a surgical revision is needed.

Investigation of the Possibility to Reduce Susceptibility Artifacts in MRI Knee Examination

The aim of this present study is to evaluate the reduction of susceptibility artifacts by increasing bandwidth (BW) and echo train length (ETL) in proton density turbo spin echo (PD TSE) sequences with and without fat saturation (FS) and in turbo inversion recovery magnitude (TIRM) sequences. We compared: (1) TIRM coronal (COR) with TIRM COR with high (H) BW and Long ETL; (2) PD TSE sagittal (SAG) FS with the PD TSE SAG FS with (H) BW; (3) PD TSE SAG with PD TSE SAG with (H) BW; (4) PD TSE SAG with PD TSE SAG with (H) BW and Long ETL. A quantitative analysis measured the extent of the susceptibility artifacts. A qualitative analysis evaluated the susceptibility artifacts, image distortion and effectiveness of fat suppression. The depiction of cartilage, menisci, muscles, tendons and bone marrow were also qualitatively analyzed. In the quantitative analysis, modified TIRM appears superior. In the qualitative analysis, the modified TIRM appears superior in 8/10 characteristics. The modified PD TSE FS is superior to the conventional regarding the susceptibility artifacts, image distortion and the depiction of bone marrow and cartilage and fat saturation. The modified PD TSE with (H) BW is found to be superior to the conventional PD TSE only in cartilage. In these sequences, when ETL was increased there were significant differences in four characteristics (ghost artifacts, cartilage, menisci and muscles). TIRM sequences with an increased BW and ETL are proposed to be used in daily clinical practice.

Diagnostic value of contrast-enhanced magnetic resonance angiography in large-vessel vasculitis.

To evaluate contrast-enhanced magnetic resonance angiography (MRA) in diagnosis of inflammatory aortic involvement in patients with clinical suspicion of large-vessel vasculitis. Seventy-five patients, mean age 62 years (range 16-82 years), 44 female and 31 male, underwent gadolinium-enhanced MRA and were evaluated retrospectively. Thoracic MRA was performed in 32 patients, abdominal MRA in 7 patients and both thoracic and abdominal MRA in 36 patients. Temporal arterial biopsies were obtained from 22/75 patients. MRA positivity was defined as increased aortic wall signal in late gadolinium-enhanced axial turbo inversion recovery magnitude (TIRM) series. The influence of prior glucocorticoid intake on MRA outcome was evaluated. MRA was positive in 24/75 patients, with lesions located in the thorax in 7 patients, the abdomen in 5 and in both thorax and abdomen in 12. Probability for positive MRA after glucocorticoid intake for more than 5 days before MRA was reduced by 89.3%. Histology was negative in 3/10 MRA-positive patients and positive in 5/12 MRA-negative patients. All 5/12 histology positive / MRA-negative patients had glucocorticoids for >5 days prior to MRA and were diagnosed as having vasculitis. Positive predictive value for MRA was 92%, negative predictive value was 88%. Contrast-enhanced MRA reliably identifies large vessel vasculitis. Vasculitic signals in MRA are very sensitive to glucocorticoids, suggesting that MRA should be done before glucocorticoid treatment.

Magnetic Resonance Imaging Signal Characteristics of Medishield: Early Postoperative Profile in a Rabbit Interlaminotomy Model

Application of Medishield to the nerve root is common during spinal surgery to create a mechanical barrier from pain mediators and reduce scar formation. However, Medishield's signal characteristics on magnetic resonance imaging (MRI) have not yet been examined. Microsurgical interlaminotomy was performed on 2 lower lumbar segments in 17 adult New Zealand white rabbits. After dural exposure, applications of 1 mL (autologous blood clot or Medishield) were randomized for each level. On postoperative days 1 through 3, various MRI sequences in 1.5T were performed including T1-weighted, T2-w, T1-gadolinium-weighted, susceptibility-weighted and turbo inversion recovery magnitude (TIRM) sequence. Signaling characteristics were analyzed by 3 blinded observers. Inter-rater agreement was calculated using Fleiss's kappa coefficient (κ). Positive and negative likelihood ratios in detecting Medishield by MRI were determined. Of 24 MRIs performed, TIRM sequence identified Medishield with the highest likelihood ratio. Medishield's positive likelihood ratio was highest (5.8) on postoperative day 1 with interobserver agreement of 93% (κ= 0.75); these rates declined to 2.5 and 1.4 on postoperative days 2 and 3 with interobserver agreements of 71% (κ= 0.43) and 83% (κ= 0.67), respectively. Medishield adherence was confirmed in each rabbit by histologic examinations. Understanding that radiologic detection of Medishield diminished over time as its signal characteristics became less distinguishable from a blood clot is essential in clinical practice. Medishield was detected on postoperative day 1 but not 2 days later after hemodynamic changes had occurred. These results may provide a guide for postoperative findings, such as differential diagnosis of hematoma.

Value of 18 F-FDG PET/MRI for the outcome of CT-guided facet block therapy in cervical facet syndrome: initial results.

The aim of this study was to evaluate the ability of 18 F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18 F-FDG PET/MRI) to detect PET-positive cervical facet arthropathy and identify patients who benefit from facet block therapy. Ten patients with cervical facet syndrome (mean age: 65 ± 12 years) underwent 18 F-FDG PET/MRI of the neck. Focal 18 F-FDG uptake in PET-positive facet joints served as target for computed tomography (CT)-guided facet blocks. In PET-negative patients, the target joint for facet block therapy was selected by current clinical standards considering the level of maximum facet arthrosis and pain. Neck pain was measured on visual analogue scale (VAS) before and after therapy. Bone marrow signal intensity (SI) ratio on turbo inversion recovery magnitude (TIRM) images and maximum standard uptake values (SUVmax) was calculated for each facet joint. Pearson's correlation coefficient (r) was calculated between bone marrow SI ratios on TIRM and SUVmax. 18 F-FDG PET/MRI detected PET-positive facet arthropathy in six patients. Patients with PET-positive facet arthropathy had significantly less pain compared with the pretreatment pain 3 h (P = 0.002), 4 weeks (P = 0.002) and 3 months (P = 0.026) after facet block therapy. Pain did not change significantly in patients with PET-negative facet arthropathy. TIRM SI ratio was higher in PET-positive facet arthropathy than in PET-negative facet arthropathy (P < 0.001). Correlation was strong between bone marrow SI ratio on TIRM images and SUVmax (r = 0.7; P < 0.001). 18 F-FDG PET/MRI can detect PET-positive cervical facet arthropathy and help to identify patients benefitting from facet block therapy. Bone marrow TIRM SI ratio might be a surrogate for PET-positive facet arthropathy.

Analisis Variasi Nilai Time Repetition (TR) dan Time Inversion (TI) terhadap Informasi Anatomi Sekuens Turbo Inversion Recovery Magnitude (TIRM) MRI Wrist Joint Dengan Menggunakan MRI 0,3 Tesla

Backgroud: The Turbo Inversion Recovery Magnitude (TIRM) pulse sequence is used to examine wrist joint, especially in the coronal plane. Main parameters of inversion recovery pulse sequence are time repetition (TR), time echo (TE) and time inversion (TI). This study aims to analyze the variation of time repetition (TR) and time inversion (TI) on anatomical information using TIRM pulse sequence on wrist joint MR imaging with 0,3 tesla.Methods: This study was a quantitave experimental study with a linear regression test. This study was conducted in Radiology Department of Banyumas hospital using twenty serial images from only one patient with 10 variation of TR (3000 ms, 3200ms, 3400 ms, 3600 ms, 3800 ms, 4000 ms, 4200 ms, 4400 ms, 4600 ms, 4800 ms) and 10 variation of TI (70 ms, 75 ms, 80 ms, 85 ms, 90 ms, 95 ms, 100 ms, 105 ms, 110 ms, 115 ms). Image assessed by only one respondent.Results: There was no significant influence of variation of TR and TI on anatomical information. Significant number was 0,240 which is bigger than p value (0,05). TR and TI variation affected just only 15,5% to anatomical information, 84,5% was influenced by other variables that unconfirmed in this study.Conclusion: There was differences of anatomical information in MRI wrist joint sequence coronal T2WI-FSE fat suppression between SPIR and SPAIR with a significance level of p value 0.001 (p 0.05). SPAIR is the method which is clearer to show the anatomical information of wrist joint.

MRI in pediatric neck abscesses

Imaging plays an important role for therapy planning in patients with suspected neck abscess, which can be life-treatening. The purpose of this retrospective study was to assess the sensitivity and specificity of magnetic resonance imaging (MRI) for neck abscess detection in pediatric patients. Thirty patients (14 m, 16 f; age range 2 mo – 16 yr; mean age 5 yr 6 mo) with suspected deep neck infection were examined on a 1.5 T MRI scanner. The MRI protocol included contrast-enhanced and nonenhanced images. The reference standard was based on surgical findings (26 patients) or on follow-up (four patients). The scans were evaluated independently by two board certified radiologists. Cohen`s kappa was used to assess inter-rater agreement. Diagnostic confidence for the contrast-enhanced images and turbo inversion recovery magnitude images was compared using the Wilcoxon test. Twenty-seven out of thirty patients had abscesses. Sensitivity and specificity for abscesses was 100%. Both readers agreed in 29 of 30 cases ( κ = 0,84). Diagnostic confidence was higher when using contrast-enhanced images alone in comparison to turbo inversion recovery magnitude images ( p = 0.008). MRI has excellent sensitivity and specificity for head and neck abscesses in pediatric patients. The use of contrast media improves the diagnostic confidence for detecting abscesses.

SU-E-I-62: Reduction of Susceptibility Artifacts by Increasing the Bandwidth (BW) and Echo Train Length (ETL)

Purpose: The aim of this present study is to increase bandwidth (BW) and echo train length (ETL) in Proton Density Turbo Spin Echo (PD TSE) sequences with and without fat saturation (FS) as well as in Turbo Inversion Recovery Magnitude sequences (TIRM) in order to assess whether these sequences are capable of reducing susceptibility artifacts. Methods: We compared 1) TIRM coronal (COR) with the same sequence with increased both BW and ETL 2) Conventional PD TSE sagittal (SAG) with FS with an increased BW 3) Conventional PD TSE SAG without FS with an increased BW 4) Conventional PD TSE SAG without FS with increased both BW and ETL. A quantitative analysis was performed to measure the extent of the susceptibility artifacts. Furthermore, a qualitative analysis was performed by two radiologists in order to evaluate the susceptibility artifacts, image distortion and fat suppression. The depiction of cartilage, menisci, muscles, tendons and bone marrow were also qualitatively analyzed. Results: The quantitative analysis found that the modified TIRM sequence is significantly superior to the conventional one regarding the extent of the susceptibility artifacts. In the qualitative analysis, the modified TIRM sequence was superior to the corresponding conventional one in eight characteristics out of ten that were analyzed. The modified PD TSE with FS was superior to the corresponding conventional one regarding the susceptibility artifacts, image distortion and depiction of bone marrow and cartilage while achieving effective fat saturation. The modified PD TSE sequence without FS with a high (H) BW was found to be superior corresponding to the conventional one in the case of cartilage. Conclusion: Consequently, TIRM sequence with an increased BW and ETL is proposed for producing images of high quality and modified PD TSE with H BW for smaller metals, especially when FS is used.

Oncological whole-body staging in integrated 18F-FDG PET/MR: Value of different MR sequences for simultaneous PET and MR reading

ObjectiveTo evaluate different magnetic resonance (MR) imaging sequences in integrated positron emission tomography (PET)/MR concerning their ability to detect tumors and allocate increased radionuclide uptake on 18F-fluorodeoxyglucose (18F-FDG) PET in intraindividual comparison with computed tomography (CT) from PET/CT. Material and methodsSixty-one patients (34 female, 27 male, mean age 57.6y) who were examined with contrast-enhanced PET/CT and subsequent PET/MR (mean delay for PET/MR after injection: 147±43min) were included. A maximum of ten 18F-FDG-avid lesions per patient were analyzed on CT from PET/CT and with the following MR sequences from PET/MR: T2, turbo inversion recovery magnitude (TIRM), non-enhanced T1, contrast-enhanced T1, and diffusion-weighted imaging (DWI). All lesions were rated using a four-point ordinal scale (scored from 0 to 3) concerning visual detectability of the lesion against the surrounding background and anatomical allocation of the PET finding. In each category (detectability and allocation), Wilcoxon rank sum tests were performed. Bonferroni–Holm correction was performed to prevent α-error accumulation. ResultsIn 225 18F-FDG-avid lesions (156 confirmed as malignant by radiological follow up, 69 by histopathology), visual detectability was comparably high on CT (mean: 2.5±0.9), TIRM (mean: 2.5±0.9), T2 (mean: 2.4±0.9), and DWI (mean: 2.5±1.0) and was significantly higher than on non-enhanced T1 (mean: 2.2±1.0). While anatomic allocation of the PET finding was comparable with CT (mean: 2.6±0.7), T2 (mean: 2.6±0.7), and TIRM (mean: 2.8±0.7), it was significantly higher compared to DWI (mean: 2.1±1.0) and non-enhanced T1 (mean: 2.4±0.8). ConclusionIn conclusion, T2, TIRM, and contrast-enhanced T1 provide a high quality of lesion detectability and anatomical allocation of FDG-avid foci. Their performance is at least comparable to contrast-enhanced PET/CT. Non-enhanced T1 may be omitted and the necessity of DWI should be further investigated for specific questions, such as assessment of the liver.

Usefulness of metal artifact reduction with WARP technique at 1.5 and 3T MRI in imaging metal-on-metal hip resurfacings.

To evaluate the usefulness of the metal artifact reduction technique "WARP" in the assessment of metal-on-metal hip resurfacings at 1.5 and 3T in the context of image quality and imaging speed. Nineteen patients (25 hip resurfacings) were randomized for 1.5 and 3T MRI, both including T1 and T2 turbo spin-echo as well as turbo inversion recovery magnitude sequences with and without view angle tilting and high bandwidth. Additional 3T sequences were acquired with a reduced number of averages and using the parallel acquisition technique for accelerating imaging speed. Artifact size (diameter, area), image quality (5-point scale) and delineation of anatomical structures were compared among the techniques, sequences and field strengths using the Wilcoxon sign-rank and paired t-test with Bonferroni correction. At both field strengths, WARP showed significant superiority over standard sequences regarding image quality, artifact size and delineation of anatomical structures. At 3T, artifacts were larger compared to 1.5T without affecting diagnostic quality, and scanning time could be reduced by up to 64% without quality degradation. WARP proved useful in imaging metal-on-metal hip resurfacings at 1.5T as well as 3T with better image quality surrounding the implants. At 3T imaging could be considerably accelerated without losing diagnostic quality.