Dynamic MRI Imaging Research Articles

Degenerative Cervical Myelopathy: An Overview.

Degenerative cervical myelopathy (DCM) is a spinal condition of growing importance due to its increasing prevalence within the ageing population. DCM involves the degeneration of the cervical spine due to various processes such as disc ageing, osteophyte formation, ligament hypertrophy or ossification, as well as coexisting congenital anomalies. This article provides an overview of the literature on DCM and considers areas of focus for future research. A patient with DCM can present with a variety of symptoms ranging from mild hand paraesthesia and loss of dexterity to a more severe presentation of gait disturbance and loss of bowel/bladder control. Hoffman's sign and the inverted brachioradialis reflex are also important signs of this disease. The gold standard imaging modality is MRI which can identify signs of degeneration of the cervical spine. Other modalities include dynamic MRI, myelography, and diffusion tensor imaging. One important scoring system to aid with the diagnosis and categorisation of the severity of DCM is the modified Japanese Orthopaedic Association score. This considers motor, sensory, and bowel/bladder dysfunction, and categorises patients into mild, moderate, or severe DCM. DCM is primarily treated with surgery as this can halt disease progression and may even allow for neurological recovery. The surgical approach will depend on the location of degeneration, the number of cervical levels involved and the pathophysiological process. Surgical approach options include anterior cervical discectomy and fusion, corpectomy, or posterior approach (laminectomy ± fusion). Conservative management is also considered for some patients with mild or non-progressive DCM or for patients where surgery is not an option. Conservative treatment may include physical therapy, traction, or neck immobilisation. Future recommendations include research into the prevalence rate of DCM and if there is a difference between populations. Further research on the benefit of conservative management for patients with mild or non-progressive DCM would be recommended.

Simulation of the mobility of the pelvic system: influence of fascia between organs

The mobility of pelvic organs is the result of an equilibrium called Pelvic Static characterizing the balance between the properties and geometries of organs, suspensions and support system. Any imbalance in this complex system can cause of pelvic static disorder. Genital prolapse is a common hypermobility pathology which is complex, multi factorial and its surgical management has high rate of complications. The use of 3 D numerical models and simulation enables the role of the various suspension structures to be objectively studied and quantified. Fascias are connective tissues located between organs. Although their role are described as important in various descriptions of pelvic statics, their influence and role has never been quantitatively objectified. This article presents a refine Finite Element (FE) model for a better understanding of biomechanical contribution of inter-organ fascia. The model is built from MRI images of a young volunteer, the mechanical properties derived from literature data to take into account the age of the patient and new experimental results have enabled an order of magnitude of the mechanical properties of the fascias to be defined. The FE results allows to quantify the biomechanical role of the fascia on pelvic mobility quantified by an analysis of dynamic MRI images and a local mapping of the gap between calculated and measured displacements. This improved numerical model integrating the fascias makes it possible to describe pelvic mobilities with a gap of 1 mm between numerical simulations and measurements, whereas without taking them into account this gap locally reaches 20 mm.

Additive role of dynamic subtraction MRI in assessment of unresolved HCC post-radiofrequency ablation

BackgroundMalignant Hepatocellular carcinoma (HCC) is one amongst the foremost widespread cancers within the world. Radiofrequency ablation (RFA) is that the most generally used substitute tool for hepatic carcinoma treatment. Monitoring tumoral response to loco-regional therapy is a vital mission in oncological imaging. Dynamic contrast enhanced MR and recently added subtraction imaging technique improve assessment of the ablated hepatic focal lesions. The aim of this study is that the evaluation of the role of Subtraction MRI within the detection of recurrent or residual tumoral viability after RF ablation.ResultsFifty patients were conducted during this retrospective study, all underwent RFA for 76 hepatic focal lesions and underwent Dynamic MRI study 1 month after ablation. Subtraction imaging was then performed. MRI images were interpreted by two readers who are experienced in hepatic imaging. The primary reader interpreted the standard Dynamic MRI and was blinded to the subtraction sequences; the second reader interpreted both Dynamic and Subtraction MRI images. the primary reader detected 49 resolved cases by dynamic MRI, while the second reader detected residual activity in 6 cases out of 49 via subtraction dynamic MRI (added value). The second reader agreed with first reader in 43 cases (agreement).The first reader detected 27 residual cases by dynamic MRI. The second reader disagreed with first reader in 11 cases appeared resolved out of 27 via subtraction dynamic MRI (added value). The second reader agreed with first reader in residual activity in 16 cases (agreement).The statistical analysis of those results revealed a big additive value of the subtraction imaging to the dynamic MRI (P < 0.001) with moderate degree of agreement between the 2 diagnostic tools (Kappa value = 0.491). This implies that Subtraction MRI significantly improves the reader confidence level within the assessment of treatment response following loco-regional therapies for HCC.ConclusionDynamic Subtraction MRI is a powerful detector for real enhancement in treated HCC lesions after radiofrequency ablation and hence increasing the degree of readers’ confidence and accuracy of treated lesions in follow-up studies. So it's recommended to feature this powerful tool as a routine to any or all Dynamic MRI studies of the Liver.

Role of diffusion weighted MRI imaging in characterization of hepatic focal lesions in cirrhotic patients in comparison to dynamic cross sectional imaging

Abstract Aim of work The aim of the study is to show the feasibility of diffusion weighted (DWI) MRI with calculation of the apparent diffusion coefficient in characterization of hepatic focal lesions as well as differentiating benign from malignant lesions in cirrhotic patients. Patients and Methods The study included 35 patients (25 males and 10 females) by cross sectional study and convenient sampling at the Demerdash hospital, inclusion criteria: patients diagnosed by hepatic focal lesions on top of post-viral induced cirrhosis, detected by ultrasound, triphasic CT or dynamic MRI imaging. All patients to be included in the study underwent characterization of hepatic focal lesions to differentiate benign from malignant lesions using a combination of characteristic imaging criteria, including contrast enhancement patterns on MRI. Sequences used were T2 weighted imaging, T2 Spectral Attenuated Inversion Recovery (SPAIR), and diffusion weighted imaging sequences with estimation of the ADC map and calculation of the ADC values. Results Our study was carried on a total of 35 patients including 25 males and 10 female patients having a mean age of 59 ± 10.2 years (58.1 ± 11 and 61.2 ± 8 years for the male and female patients respectively). DWI and ADC showed statistically significant difference among the benign and malignant focal lesions in terms of their diffusion restriction criteria ( P &amp;lt; 0.0001), with a sensitivity, specificity, positive and negative predictive values of 100% (95% CI = 89.5 – 100%), 92.3% (95% CI = 79.6 – 97.3%), 91.6% (95% CI = 78.1 – 97.1%) and 100% (95% CI = 90.3 – 100%), as well as a likelihood ratio of 13. On comparing the ADC values of the focal lesions for the benign and malignant focal lesions, the malignant lesions showed statistically significant lower means as compared to the benign lesions (malignant = 1.08 ± 0.28 x 10-3 mm2/s, benign =2.0 ± 0 x 10-3 mm2/s, P &amp;lt; 0.0001). ROC curve analysis of the ADC values of the benign and malignant focal lesions was highly significant (P &amp;lt; 0.0001), with an area under curve of 0.9745 (97.45% overall accuracy), giving an ADC cut-off value of (&amp;lt; 0.98 x 10-3 mm2/s) for malignant lesions with 97.2% sensitivity (95% CI = 85.83% - 99.86%), 97.2% specificity (95% CI = 85.83% - 99.86%) and a likelihood ratio of 35. Summary and conclusion DWI MRI and the calculation of the ADC are great non invasive possible tools to detect and characterize hepatic focal lesions as well as to differentiate benign from malignant lesions in cirrhotic patients especially in patients with renal impairment and allergy to contrast media also to avoid unnecessary biopsies.

Orbital anatomy magnetic resonance imaging in diplopic versus non-diplopic patients after glaucoma drainage device placement.

New-onset persistent diplopia has become a common complication after glaucoma drainage device (GDD) placement. Understanding the orbital anatomy of such patients may provide information regarding risk of diplopia, GDD selection, and post-operative management. The purpose of this study was to examine the orbital anatomic differences in diplopic and non-diplopic patients after GDD implantation using high-resolution MRI. Seven eyes (N = 4 with diplopia and N = 3 without diplopia after GDD placement) of seven patients that had undergone placement of Baerveldt 250 (B250), Baerveldt 350 (B350), or Ahmed FP7 (FP7) GDD were prospectively enrolled at a single institution. All patients underwent a 3.0T orbital MRI with 3D volumetric T1 and T2 weighted sequence. Images were analyzed for orbital volume, axial length, orbital distances, presence of superior rectus-lateral rectus (SR-LR) band, position of GDD, and SR-LR angles. Patients with diplopia had smaller mean ± SD orbital axial (911.5 ± 111.8 mm3 vs 931.7 ± 79.7 mm3) and coronal volumes (1162.5 ± 145.5 mm3 vs 1180 ± 34.6 mm3) compared to non-diplopic patients. Average orbital rim distances were larger for the diplopic group. The SR-LR displacement angle for diplopic patients was larger (101.6° ± 8.1 vs 94.7° ± 17.6) while the SR-LR quadrantic angle (86.6° ± 4.2 vs 89.1° ± 4.3) was smaller. SR-LR band was present and intact in all patients. GDD malpositioning was not evident in any patient. The decreased orbital axial and coronal volumes as well as increased orbital rim distances in diplopic patients suggests the need for further studies to understand the role of orbital anatomy in occurrence of diplopia. Dynamic MRI imaging may be helpful in identifying differences in extraocular muscle function that reveal an etiology of diplopia in patients with GDD implantation.

The role of dynamic and diffusion MR imaging in therapeutic response assessment after microwave ablation of hepatocellular carcinoma using LI-RADS v2018 treatment response algorithm

BackgroundHepatocellular carcinoma (HCC) is considered as one of the major causes of morbidity and mortality worldwide. Microwave ablation (MWA) is a widely used treatment option having less morbidity and complications as compared with surgery and liver transplantation. MRI is the most widely used modality in the assessment of treatment response after MWA. Currently, LI-RADS v2018 algorithm is considered the cornerstone in daily clinical practice for assessment of the treatment response after locoregional therapy. The aim of the study was to assess the role of dynamic MRI and diffusion imaging in the assessment of treatment response and detection of tumor viability following microwave ablation therapy of HCC according to LI-RADS v2018 treatment response algorithm.ResultsThis retrospective study was performed over 45 HCC lesions underwent MWA as the only therapeutic procedure and followed up by dynamic MRI with diffusion images and then classified according to the LI-RADS treatment response criteria into LR-TR viable and LR-TR nonviable groups. All the malignant lesions found in this study showed arterial phase hyperenhancment (APHE), whether in the early or late arterial phases. Delayed washout was found in all malignant lesions as well. In the diffusion analysis, the mean ADC value for the malignant lesions was 0.900 ± 0.126 × 10-3 mm2/s, while the mean ADC of the treatment-related specific benign parenchymal enhancement was 1.284 ± 0.129 × 10-3 mm2/s with a significant statistical difference in between (P = 0.0001) and a cutoff value of 1.11 × 10-3 mm2/s. Our findings showed that the dynamic MRI has 100% sensitivity, 93.5% specificity, 87.5% PPV, and 100% NPV in the detection of tumoral activity compared with 71.43% sensitivity, 93.55% specificity, 83.33% PPV, and 87.88% NPV for diffusion images.ConclusionLI-RADS 2018 provides a treatment response algorithm superior to the previously used assessment criteria. MRI with dynamic contrast-enhanced technique and diffusion imaging provide a powerful tool in the evaluation of treatment response after microwave ablation of hepatocellular carcinoma using the LI-RADS treatment response criteria and is considered a reliable method in differentiating between the recurrent or residual malignant lesions and the posttreatment benign liver changes.

Correlation of prognostic factors with MRI findings in malignant breast lesions

BackgroundMagnetic resonance imaging (MRI) of the breast represents the most sensitive imaging modality in the detection of breast cancer, with a reported sensitivity between 94 and 100%. We aim to detect the correlation between MRI findings and pathologically detected prognostic factors in malignant breast lesions.Breast parenchymal density distribution, background parenchymal enhancement pattern, lesion’s morphologic features, T2WI signal characteristics, contrast enhancement, time/signal intensity curves, and lesions localizations in breast were evaluated using dynamic MRI images. Histopathological diagnosis, maximum measurements of the lesion, histological grade, presence of estrogen and/or progesterone receptors, c-erb B2, and Ki-67 parameters were noted as prognostic factors.ResultsWe cannot detect any relationship between the breast parenchymal density and prognostic factors. Mild background breast enhancement is related with ER presence, a good prognostic factor. Histopathological grade of the lesions augmented with the increase in the lesion diameters. ADC values are not related with prognostic factors.ConclusionA mild background enhancement, an intermediate signal intensity on T2WI, a high tpeak value, and absence of pathological axillary lymph node are found to be related with good prognostic factors. An irregular contour, a huge diameter, having a type III kinetic curve, a high slopei value, and presence of pathological axillary lymph node are found to be related with poor prognostic factors. MRI can be used to predict prognostic factors in breast cancer cases.

Role of dynamic sleep MRI in obstructive sleep apnea syndrome.

To identify obstruction sites of the upper airway during sleep in patients with obstructive sleep apnea syndrome (OSAS) under dynamic conditions and improve knowledge to guide surgical treatment and advancements. The study included 15 patients (5 females and 10 males) who were diagnosed as having OSAS. Overall mean age was 40.2years (± 7.01years). All the patients underwent drug-induced sleep endoscopy (DISE) and dynamic sleep MRI. The presence, location, and direction of airway collapse were assessed. Dynamic MRI findings were correlated to DISE. Data of the site and direction of airway collapse were correlated with those of endoscopic findings and interobserver agreement was done. The dynamic images in sagittal section showed collapse of the upper airway at retropalatal level in 14 patients (93.33%) and at retroglossal level in seven patients (46.7%) and of these 14 patients; seven had combined retropalatal and retroglossal collapse. These findings were highly correlated with DISE findings with an excellent interobserver agreement for retropalatal and retroglossal levels (Kappa = 1 and 0.867, P value = 0.000), respectively. Objective measurements of the direction of collapse in axial dynamic sleep MRI images showed significant statistical correlation with endoscopic findings regarding retropalatal anteroposterior and circumferential collapse (Kappa = 0.58 and 0.52, P value = 0.02 and 0.03, respectively). Dynamic sleep MRI can reliably characterize the actual site of dynamic airway obstruction and has the potential of improving predictions of successful surgical outcomes in OSAS patients.

SPARC: Simultaneous Assessment of Gastric Emptying and Motility with Contrast Enhanced Magnetic Resonance Imaging in Humans

PurposeMagnetic resonance imaging (MRI) of the gastrointestinal (GI) tract is an emerging technique for non‐invasive assessment of gastric emptying and motility in animals and humans. However, addition of MRI contrast agents to the test meal is often required to produce high luminal contrast to facilitate image analysis. Here, we reported a recipe of a test meal that is all natural (e.g. gadolinium‐free) and safe for humans. The ingredients of the test meal all contain relatively high concentration of manganese, which allow the lumen of the GI tract to be visible inside MRI. To capture gastric emptying and motility simultaneously, we have developed a dynamic 3D imaging protocol with high spatial and temporal resolution and an image segmentation and analysis algorithm.MethodSix healthy volunteers (3 woman; age 24–31) participated in this study. All subjects were asked to fast for 12 hours. Subjects were scanned using a 3T Siemens Prisma MRI scanner using an 18‐channel body coil and a 32‐channel spine coil. Prior to meal consumption, pre‐prandial gastric volume was quantified using a 3D true fast imaging (TRUFI) with steady‐state free precession sequence under free breathing. Then the subjects were instructed to ingest 350 ml of a semi‐solid test meal (263kcal) that contains blended natural foods (i.e. pineapple, banana, blueberry, firm tofu) with a relatively high concentration of manganese. Post‐meal MRI scans were performed using a 3D Spoiled Gradient Echo Variant (VIBE) sequence under gentle breaths over a 90‐minute time course. Post‐prandial gastric volumes, as well as antral contraction frequency and amplitude of the peristaltic wave, were quantified from the dynamic 3D MRI images using a custom‐built image processing pipeline.ResultsPre‐prandial gastric volume was measured prior to test meal consumption (30.98±12.29 mL). After the subjects consumed the test meal, the presence of manganese in the meal enhanced the contrast of the gastric lumen (Fig. 1). The imaging protocol collected fast real‐time MRI scans of the stomach processing and emptying of a meal and the algorithms quantified gastric motility and emptying rate. The stomach volume decreased at a rate of 1.58±0.50 mL/min, mainly attributed to volume decrease in the fundus and the corpus (1.31±0.53 mL/min) than in the antrum (0.28±0.15 mL/min). The frequency of gastric contractions was 2.79±0.17 cycles/min, which was in line with the frequency of gastric slow wave in humans. The displacement of the luminal wall (i.e. contraction amplitude) was greater at the antrum (7.42±1.39 mm) than at the fundus and the corpus (4.52±0.25 mm), as illustrated in Fig. 2.ConclusionHere, we developed a contrast‐enhanced gastric MRI protocol to non‐invasively monitor gastric emptying and motility in humans. Such experimental protocol was further empowered by advanced image analysis to enable comprehensive assessment of gastric functions and physiology. In summary, the proposed method may become a reliable standard to guide diagnosis and treatment of gastric disorders in humans.Support or Funding InformationNIH SPARC OT2OD023847Example gastric MRI images of the stomach distended with the test meal. The contrast of the gastric lumen was significantly enhanced due to the presence of manganese in the meal.Figure 1Mapping amplitude of gastric contractions on the luminal wall. The displacement of the luminal wall was greatest at the antrum, followed by the corpus, and smallest at the fundus.Figure 2

Early response assessment through multiparametric MRI based endpoints in a phase II multicenter study evaluating the efficacy of DPX-Survivac, intermittent low dose cyclophosphamide (CPA) and pembrolizumab combination study in subjects with solid tumors.

e14245 Background: Accurate assessment of tumor response to immunotherapy is challenged by pseudoprogression that mimics true progression. Conventional imaging and RECIST assessment do not adequately distinguish between them given their inability to account for changes in the tumor microenvironment. DPX-Survivac is a novel T cell activating therapy that triggers immune responses against tumors expressing survivin and is being studied in this trial in combination with CPA and pembrolizumab in several solid tumors. Multiparametric MRI approaches - dynamic contrast-enhanced MRI and diffusion-weighted imaging MRI are useful for accurate assessment of structural, perfusion and vascular assessment of the lesion and may identify pseudoprogression and compare to the RECIST-based assessment. Methods: The study will enroll up to 226 evaluable subjects in 5 different cohorts: ovarian cancer, HCC, NSCLC, bladder cancer and MSI-H cancer. These subjects will undergo initial imaging 28 days prior to treatment, to be assessed based on RECIST 1.1, and a pre-treatment tumor biopsy for quantitation of survivin and PD-L1 expression and MSI analyses. Treatment for 35 cycles or until disease progression. All patients will have CT images for RECIST 1.1 and iRECIST assessment. A subset of subjects will undergo mpMRI to calculate advanced imaging biomarkers. Results: MRI, clinical and patient-reported outcomes will be analyzed. Conclusions: This study will provide important evidence on the utility of mpMRI + CT-based assessment of response to immunotherapy and use it as an adjunct to the CT-based RECIST criteria by providing insight on how tumor lesions are impacted by treatment.

Self-prior image-guided MRI reconstruction with dictionary learning.

A novel method, named self-prior image-guided MRI reconstruction with dictionary learning (SPIDLE), is developed to improve the performance of MR imaging with high acceleration rates. "self-prior" means that the prior image is obtained from the target image itself and any extra MRI scans are not needed. The proposed method integrates self-prior image constraint with compressed sensing (CS) and the dictionary learning (DL) technique. The self-prior image is a preliminary result reconstructed using the undersampled k-space measurements of the target image. Therefore, the self-prior image has similar structural features with the target image, and they match each other accurately. CS approach is applied to the residual error of the target image with the self-prior image, because the error image is much sparser than the target image. The split Bregman method is used to solve the proposed approach to promote fast convergence. For multicoil measurements, each coil image is reconstructed individually and the final result is produced as the square root of sum of squares (SOS) of all channel images. The performance of the proposed SPIDLE method was inspected using different undersampling schemes and acceleration rates with various types of invivo MR datasets. Experiments showed that the SPIDLE method is superior to other typical state-of-the-art methods. Specifically, the SPIDLE method produces fewer reconstruction errors, and it is robust to initialization. The proposed SPIDLE method substantially widens the applications of prior image-guided MRI reconstruction, especially for applications that are not suitable to use existing MR scans as prior images. The SPIDLE method obviously improves the reconstruction quality for highly undersampled MRI. It is also promising for reconstruction of dynamic MRI and other imaging modalities, such as CT and CT-MRI multimodality imaging.

Robust Tensor Approximation With Laplacian Scale Mixture Modeling for Multiframe Image and Video Denoising

Sparse and low-rank models have been widely studied in the literature of signal processing and computer vision. However, as the dimensionality of dataset increases (e.g., multispectral images, dynamic MRI images, and video sequences), the optimality of vector and matrix-based data representations and modeling tools becomes questionable. Inspired by recent advances in sparse and low-rank tensor analysis, we propose a novel robust tensor approximation (RTA) framework with the Laplacian Scale Mixture (LSM) modeling for three-dimensional (3-D) data and beyond. Our technical contributions are summarized as follows: first, conceptually similar to robust PCA, we consider its tensor extension here—i.e., low-rank tensor approximation in the presence of outliers modeled by sparse noise; second, built upon previous work on tensor sparsity, we propose to model tensor coefficients with an LSM prior and formulate a maximum a posterior estimation problem for noisy observations. Both unknown sparse coefficients and hidden LSM parameters can be efficiently estimated by the method of alternating optimization; and third, we have derived closed-form solutions for both subproblems and developed computationally efficient denoising techniques for multiframe images and video. Experimental results on three datasets have shown that the proposed algorithm can better preserve the sharpness of important image structures and outperform several existing state-of-the-art image/video denoising methods (e.g., BM4D/VBM4D and tensor dictionary learning).

Remediating abnormal oral cavity motor strategies in a horn player using RT-MRI: a case study

This study uses real-time (cine) MRI to examine how orofacial myofunctional disorders (OMDs) affect muscle function during speech and horn playing. Dynamic MRI images were captured of an OMD subject and control subjects reciting a speech task and sustaining a note on an MRI-compatible horn. A following visual feedback session allowed the OMD subject to view and react to their (cine) MRI next to the image of an elite subject. Profile lines created in MATLAB allowed analysis of muscle function and changes in oral cavitation between the OMD and control subjects. In both the speech and horn films, the OMD subject consistently utilized maladaptive muscle movements, resulting in low and forward tongue position against the front teeth. Both control subjects had tongue placement free of the front teeth, and the horn control subject could elevate the tongue to narrow the air stream and play higher pitches. The MRI films suggest a connection between speech disorders and compromised horn-playing technique. OMDs limit the ability of the tongue to make the changes in oral cavitation used to play different pitches on the horn.

Contrast-Enhanced Magnetic Resonance Imaging with Magnetic Transfer Effect in Differential Diagnosis of Hemangiomas and Metastases of Liver

Objective: to investigate the operating characteristics of contrast MRI of the liver using magnetization transfer effect in the differential diagnosis of hemangiomas and metastatic lesions in comparison with dynamic contrast.Material and methods. The material of the study were dynamic contrast MRI images of 25 patients with diagnosis of direction of focal liver lesion. Inclusion criteria were detection of typical MR-semiotic for hemangioma (n = 10 to 40% of cases) or multiple liver metastases (n = 15 to 60% of cases).In the group with metastases exclusion criteria was the primary detection of obscure single focal lesions, as well as the diagnosis of other primary tumors, in particular cholangiocellular cancer (n = 1). All MRI studies were performed using MRI Toshiba Titan Octave with of 1.5 Tesla magnetic field. T1-weighted static contrast MRI investigation of liver performed after 3–5 minutes after a series of dynamic contrast MRI with modes: T1-FE-FSat and T1-TSEMTS (Δf = -210 Hz, FA = 600°). The magnevist at a dose of 0.1 mmol/kg was used as a contrast agent. Each focal liver lesion differentiated between hemangiomaand metastasis with the calculation of contrast ratio (CR) for each lesion. Statistical analysis of CR was performed using T-test and T-test Welch. The sensitivity and specificity parameters were compared during the ROC-analysis.Results. In our statistical analysis groups formed not from patients, because we were compared results about focal lesions of a liver referred to metastasis or hemangiomas. All the patients included in a research had focal lesions mostly multiple and in the comparative analysis of contrast ratio in the T1-FE-FSat and T1-TSE-MTC was carried out on 21 (20%) hemangiomas and 84 (80%) metastasises. The significant (p &lt; 10–4) contrast enhancement using T1-TSE-MTS, as in the case of hemangiomas and in metastatic lesions relative to T1-FE-FSat revealed by comparing the CRs. No significant differences were found in the differentiation of hemangiomas and liver metastases in modes T1-FE-FSat and T1-TSE-MTS when paired comparison of ROC-curves (p &gt; 0.18). No significant differences were found when paired comparison of CRs between hemangiomas in T1-FE-FSat mode and metastases in T1-TSEMTSimages (p &gt; 0.8). An additive effect (sensitivity and specificity – 98.8% and 85.7%) occurs when we used to CRcomm=35.7% in T1-FE-FSat modes and T1-TSE-MTS.Conclusions. 1. Contrast MRI using magnetization transfer effect allows significantly increase the contrast of focal liver formations on the type of hemangiomas and metastases. 2. The achieved contrast level in 2D TSE images with magnetization transfer effect of liver metastatic foci corresponds to that of hemangiomas in 2D FE mode. 3. Maximum parameters of sensitivity and specificity in the differential diagnosis of hemangiomas and liver metastases obtained by using 2D-FE-FSat and 2D-TSE-MTC in post contrast phase.

MRI in Coccydynia

Patients who are diagnosed clinically as Coccygodynia often do not get satisfactory relief. The clinical diagnosis is based on various hypotheses that have been proposed to explain the pain of coccydynia - including coccygeal spicules, pain from the pericoccygeal soft tissues, pelvic floor muscle spasm, referred pain from lumbar pathology, arachnoiditis of the lower sacral nerve roots, local posttraumatic lesions, somatization, etc. The diagnosis is difficult and the pathophysiology is poorly understood. Till recently, use of dynamic X-rays and MRI imaging was not considered to diagnose this condition. The author would like to report three patients who presented to the pain clinic with refractory coccygeal pain and underwent dynamic coccyx X-rays and MRI as part of their evaluation. All these patients had positive findings on MRI. These patients were treated satisfactorily as a result of the added diagnostic value of MRI.

Hirayama disease: Is surgery an option?

IntroductionHirayama disease is a rare cervical myelopathy, predominantly affecting young men, and which presents with distal atrophy of the upper limbs as its first and main symptom. It must be differentiated from motor neuron diseases because its natural history is different and because HD tends to stabilise in less than 5 years.Diagnosis is based on clinical findings and dynamic flexion MRI showing segmental spinal muscular atrophy, detachment of the posterior dura mater and venous congestion in the epidural space.The tendency is to indicate conservative treatment and no indications for surgery have been established. PatientsWe present 4 cases meeting both clinical criteria and dynamic MRI imaging criteria for a diagnosis of Hirayama disease. Two have stabilised spontaneously over the course of many years, and MRI scans show that typical changes have disappeared. Another case also remains stable following a shorter observation time. The fourth case is a young man who developed severe myelopathy in just over a year, and therefore underwent surgery. While his follow-up time is still short, his condition remains stable. ConclusionsOur 4 cases suggest that the condition of most patients with Hirayama stabilises naturally; patients should be evaluated for surgery on an individual basis, and surgery should probably be limited to the most severe cases that have progressed quickly.

Importance of outer-sphere and aggregation phenomena in the relaxation properties of phosphonated gadolinium complexes with potential applications as MRI contrast agents.

A series composed of a tetra-, a tris- and a bisphosphonated ligand based on a pyridine scaffold (L(4) , L(3) and L(2) , respectively) was studied within the frame of lanthanide (Ln) coordination. The stability constants of the complexes formed with lanthanide cations (Ln=La, Nd, Eu, Gd, Tb, Er and Lu) were determined by potentiometry in aqueous solutions (25.0 °C, 0.1 M NaClO4 ), showing that the tetraphosphonated complexes are among the most stable Ln(III) complexes reported in the literature. The complexation of L(4) was further studied by different titration experiments using mass spectrometry and various spectroscopic techniques including UV/Vis absorption, and steady state and time-resolved luminescence (Ln=Eu and Tb). Titration experiments confirmed the formation of highly stable [LnL(4) ] complexes. (31) P NMR experiments of the LuL(4) complex revealed an intramolecular interconversion process which was studied at different temperatures and was rationalized by DFT modelling. The relaxivity properties of the Gd(III) complexes were studied by recording their (1) H NMRD profiles at various temperatures, by temperature dependent (17) O NMR experiments (GdL(4) ) and by pH dependent relaxivity measurements at 0.47 T (GdL(3) and GdL(2) ). In addition to the high relaxivity values observed for all complexes, the results showed an important second-sphere contribution to relaxivity and pH dependent variations associated with the formation of aggregates for GdL(2) and GdL(3) . Finally, intravenous injection of GdL(4) to a mouse was followed by dynamic MRI imaging at 1.5 T, which showed that the complex can be immediately found in the blood stream and rapidly eliminated through the liver and in large part through the kidneys.

Diagnosis of hepatocellular carcinoma

More than 90% of cases of hepatocellular carcinoma occur on the background of chronic liver disease. Its diagnosis should therefore be based on six-month ultrasound screening, which should be started in these patients. The positive diagnosis of hepatocellular carcinoma is based on its vascularization examined on dynamic CT or MRI images after contrast enhancement. Arterial hypervascularization followed by a washout from the lesion in the portal and/or late phases on a background of cirrhosis provides a positive diagnosis of HCC without histology for nodules over a centimeter in size (international guidelines). Any other appearances require needle biopsy of the nodule and extra-nodular area to confirm the diagnosis. The local staging assessment predominantly involving portal invasion and the general patient assessment should be combined with assessment of the underlying liver disease to guide the treatment decision. The information obtained should be contained in as standardized a report as possible with all of the information required for patient management.

Image-based simulation of urethral distensibility and flow resistance as a function of pelvic floor anatomy.

The goal of this study is to develop an image-based model of urethral distention and resistance in women with and without SUI. A biomechanical vector force model was created to simulate the mechanical deformation of pelvic floor structures during cough and Valsalva in order to measure urethral distension and predict flow resistance patterns. Dynamic MRI images were used to create a spatial model to construct an accurate representation of tissue thickness and location, which was combined with tissue property values (MATLAB 2011a, MathWorks, Natick, MA). Spatial profiles were created to demonstrate the effects of hypermobility and tissue property variability on distensibility and flow resistance along the urethra. Sensitivity analyses were conducted to demonstrate the relationship between flow resistance and various tissue properties. The average distension for incontinent cases (3.8 mm) was significantly greater than that of continent cases (2.6 mm) (t = 3.3083, df = 8, P < 0.01), corresponding to a 70% drop in average resistance to urine flow. Sensitivity analyses demonstrated that the stiffness and contractility of the vagina and urethra had the greatest effect on continence. We present a novel, 2-dimensional biomechanical model of female stress urinary incontinence (SUI) that relates the effects of various factors such as tissue elasticity, pelvic floor structure, and muscle activation. A better understanding of the pathophysiology underlying SUI has potential implications for the creation of novel targeted treatments.

Enfermedad de Hirayama: ¿operar o no operar?

IntroductionHirayama disease is a rare cervical myelopathy, predominantly affecting young males, which presents with distal atrophy of the upper limbs as its first and main symptom. It must be differentiated from motor neuron diseases because its natural history is different and because HD tends to stabilise in less than 5 years.Diagnosis is based on clinical findings and dynamic flexion MRI showing segmental spinal muscular atrophy, detachment of the posterior dura mater and venous congestion in the epidural space.The tendency is to indicate conservative treatment and no indications for surgery have been established. PatientsWe present 4 cases meeting both clinical criteria and dynamic MRI imaging criteria for a diagnosis of Hirayama disease. Two have stabilised spontaneously over the course of many years, and MRI scans show that typical changes have disappeared. Another case also remains stable following a shorter observation time. The fourth case is a young man who developed severe myelopathy in just over a year, and therefore underwent surgery. While his follow-up time is still short, his condition remains stable. ConclusionsOur 4 cases suggest that the condition of most patients with Hirayama stabilises naturally; patients should be evaluated for surgery on an individual basis, and surgery should probably be limited to the most severe cases that have progressed quickly.