Magnetic Resonance Imaging Signal Intensity Research Articles

Efficacy and safety of hydrogen gas versus standard therapy in Chinese patients with cerebral infarction: A pilot study

Purpose: To evaluate the efficacy and safety of hydrogen (H2) gas versus standard therapy in Chinese patients with acute cerebral infarction (ACI)Method: Chinese patients with ACI who had National Institutes of Health stroke scale (NIHSS) scores of 2 - 6 were enrolled and randomized to receive hydrogen gas through inhalation route or standard therapy. Hydrogen gas (3 %) was administered twice daily for 1 hour each over a period of 2 weeks using a facial mask (non-rebreathing). Standard treatment included edaravone 30 mg (iv every 12 h + antiplatelet drugs for 2 weeks. Efficacy endpoints were change in vital signs, change in NIHSS scores from baseline, change in magnetic resonance imaging (MRI) signal intensity, and improvement in rehabilitation index. Safety was also assessed.Results: Data for 200 patients were analyzed. Patients treated with H2 gas had significantly greater improvement in NIHSS score than patients treated with standard therapy. This indicates that the neurological improvement was significantly greater in patients treated with H2 gas than those that received standard therapy for all the days tested (p < 0.05). The onset of NIHSS score reduction was faster in patients treated with H2 gas when compared to standard therapy. Furthermore, H2 gas demonstrated significant improvement in MRI signal Intensity score, which indicates that H2 gas was effective in recovery of infraction site.Conclusion: The findings of this study show that H2 gas administered via the inhalation route is effective and safe in Chinese patients with acute cerebral infarction, and is therefore, superior to standard therapy.

Endolymphatic sac tumour: exploring the role of CT and MRI features in the diagnosis of 22 cases

To explore the role of imaging features in the diagnosis of endolymphatic sac tumour (ELST). Twenty-two patients with ELST confirmed at histopathology were included in this retrospective study. All patients underwent computed tomography (CT) and magnetic resonance imaging (MRI) examinations, including diffusion-weighted imaging (DWI; n=18) and dynamic contrast-enhanced (DCE) MRI (n=3). The imaging features of this series were analysed. All lesions appeared as irregular soft-tissue mass lesions located in the middle and posterior margin of the petrous bone. At CT, the normal vestibular aqueduct structure disappeared. Multiple osteoid tissues were present inside the tumour, and destructive bone changes had a "honeycomb" pattern. Twenty cases were accompanied by the incomplete thin bony peripheral rim along the medial margin. On both T1-weighted imaging (WI) and T2WI, all lesions showed hyperintense, hypointense, and isointense mixed signal intensity. Scattered peripheral hyperintensities were found in all cases on T1WI. The mean apparent diffusion coefficient (ADC) value of 18 lesions was (1.35±0.13)×10-3 mm2/s, which was similar to that of masseter muscles. On enhanced T1WI, all lesions had significant heterogeneous enhancement, and the vascular flowing-void effect was seen in larger lesions (≥1.5 cm). The time-signal intensity curve (TIC) showed a plateau type in all three cases. The imaging features of ELST, including its location, bone destruction form, MRI signal intensity, and enhancement pattern, are helpful to improve the diagnostic accuracy of this rare tumour.

Relationship between histological tumor margins and magnetic resonance imaging signal intensities in brain neoplasia of dogs.

BackgroundIntracranial neoplasia is relatively common in dogs and stereotactic radiotherapy, surgical debulking, or both, are the most successful treatment approaches. A key component of treatment planning involves delineating tumor margin on magnetic resonance imaging (MRI) examinations. How MRI signal intensity alterations relate to histological tumor margins is unknown.ObjectivesDirectly compare histological brain sections to MRI sequence images and determine which sequence alteration best correlates with tumor margins.AnimalsFive dogs with glioma, 4 dogs with histiocytic sarcoma, and 3 dogs with meningioma.MethodsRetrospective cohort study. Histological brain sections were registered to in vivo MRI scan images obtained within 7 days of necropsy. Margins of signal intensity alterations (T2‐weighted, fluid‐attenuating inversion recovery [FLAIR], T1‐weighted and contrast enhancement) were compared directly to solid tumor and surgical margins identified on histology. Jacquard similarity metrics (JSM) and cross‐sectional areas were calculated.ResultsIn glioma cases, margins drawn around T2‐weighted hyperintensity were most similar to surgical margins (JSM, 0.66 ± 0.17) when compared to other sequences. In both meningioma (JSM, 0.57 ± 0.21) and histiocytic sarcoma (JSM, 0.75 ± 0.11) margins of contrast enhancement were most similar to surgical margins.Conclusions and Clinical ImportanceSignal intensities correspond to tumor margins for different tumor types and facilitate surgical and radiation therapy planning using MRI images.

A Case of Odontogenic Myxoma of the Mandible with Expansion to the Alveolar Crest – Comparison of Imaging Findings and Pathological Findings: A Case Report

Background: An odontogenic myxoma is an intraosseous tumor characterized by stellate and spindle-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. We herein describe an odontogenic myxoma that expanded not only to the bone marrow but also to the outside of the alveolar bone. Diagnosis of an odontogenic myxoma in a tooth-deficient region by imaging findings alone was difficult because the positional relationship between the tumor and the tooth is unknown. Furthermore, some of these odontogenic myxomas reportedly show rapid growth. Case Report: Here, we present the case of a patient, a 44-year-old man, who had a hard, bone-like swelling on his right mandible molar region and mild paresthesia on his right cheek. An odontogenic myxoma and ameloblastoma were suspected based on the imaging findings; however, pathological examination of the biopsy led to a diagnosis of odontogenic myxoma. Right segmental mandibulectomy was performed, and there was no recurrence observed after surgery. Conclusion: To improve the accuracy of imaging diagnosis, it is important to compare the imaging findings with the pathological findings of the surgical specimen. This comparison in the present case revealed differences in the magnetic resonance imaging signal intensity in regions with different types of cell components.

MRI Appearance of Focal Lesions in Liver Iron Overload.

Liver iron overload is defined as an accumulation of the chemical element Fe in the hepatic parenchyma that exceeds the normal storage. When iron accumulates, it can be toxic for the liver by producing inflammation and cell damage. This can potentially lead to cirrhosis and hepatocellular carcinoma, as well as to other liver lesions depending on the underlying condition associated to liver iron overload. The correct assessment of liver iron storage is pivotal to drive the best treatment and prevent complication. Nowadays, magnetic resonance imaging (MRI) is the best non-invasive modality to detect and quantify liver iron overload. However, due to its superparamagnetic properties, iron provides a natural source of contrast enhancement that can make challenging the differential diagnosis between different focal liver lesions (FLLs). To date, a fully comprehensive description of MRI features of liver lesions commonly found in iron-overloaded liver is lacking in the literature. Through an extensive review of the published literature, we aim to summarize the MRI signal intensity and enhancement pattern of the most common FLLs that can occur in liver iron overload.

Simultaneous Discrete Intradiploic and Intracerebral Atypical Epidermoid Cysts: Possible Embryological Theories

Epidermoid cysts are benign indolent lesions that account for around 1% of all primary brain tumours. Embryologically, they are thought to arise from entrapped ectodermal elements during neural tube closure. They often display classic magnetic resonance imaging (MRI) characteristics compared to atypical 'white epidermoids' which display reversed MRI signal intensities.

Altered Gray Matter Cortical and Subcortical T1-Weighted/T2-Weighted Ratio in Premature-Born Adults

BackgroundMicroscopic studies in newborns and animal models indicate impaired myelination after premature birth, particularly for cortical myelination; however, it remains unclear whether such myelination impairments last into adulthood and, if so, are relevant for impaired cognitive performance. It has been suggested that the ratio of T1-weighted (T1w) and T2-weighted (T2w) magnetic resonance imaging signal intensity (T1w/T2w ratio) is a proxy for myelin content. We hypothesized altered gray matter (GM) T1w/T2w ratio in premature-born adults, which is associated with lower cognitive performance after premature birth. MethodsWe analyzed GM T1w/T2w ratio in 101 adults born very premature (VP) and/or at very low birth weight (VLBW) (<32 weeks of gestation and/or birth weight <1500 g) and 109 full-term control subjects at 26 years of age, controlled for voxelwise volume alterations. Cognitive performance was assessed by verbal, performance, and full scale IQ using the Wechsler Adult Intelligence Scale. ResultsSignificantly higher T1w/T2w ratio in VP/VLBW subjects was found bilaterally in widespread cortical areas, particularly in frontal, parietal, and temporal cortices, and in putamen and pallidum. In these areas, T1w/T2w ratio was not related to birth variables, such as gestational age, or IQ scores. In contrast, significantly lower T1w/T2w ratio in VP/VLBW subjects was found in bilateral clusters in superior temporal gyrus, which was associated with birth weight in the VP/VLBW group. Furthermore, lower T1w/T2w ratio in left superior temporal gyrus was associated with lower full scale and verbal IQ. ConclusionsResults demonstrate GM T1w/T2w ratio alterations in premature-born adults and suggest altered GM myelination development after premature birth with lasting and functionally relevant effects into early adulthood.

In vivo tracking of unlabelled mesenchymal stromal cells by mannose-weighted chemical exchange saturation transfer MRI.

The tracking of the in vivo biodistribution of transplanted human mesenchymal stromal cells (hMSCs) relies on reporter genes or on the addition of exogenous imaging agents. However, reporter genes and exogenous labels may require bespoke manufacturing and regulatory processes if used in cell therapies, and the labels may alter the cells' properties and are diluted on cellular division. Here we show that high-mannose N-linked glycans, which are abundantly expressed on the surface of hMSCs, can serve as a biomarker for the label-free tracking of transplanted hMSCs by mannose-weighted chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI). For live mice with luciferase-transfected hMSCs transplanted into their brains, post-mortem fluorescence staining with a mannose-specific lectin showed that increases in the CEST MRI signal, which correlated well with the bioluminescence intensity of viable hMSCs for 14 days, corresponded to the presence of mannose. In vitro, osteogenically differentiated hMSCs led to lower CEST MRI signal intensities owing to the concomitantly reduced expression of mannose. The label-free imaging of hMSCs may facilitate the development and testing of cell therapies.

The Effect of Gadolinium-Based Contrast Agents on Longitudinal Changes of Magnetic Resonance Imaging Signal Intensities and Relaxation Times in the Aging Rat Brain.

ObjectivesThe aim of the study was to investigate the possible influence of changes in the brain caused by age on relaxometric and relaxation time–weighted magnetic resonance imaging (MRI) parameters in the deep cerebellar nuclei (DCN) and the globus pallidus (GP) of Gd-exposed and control rats over the course of 1 year.Materials and MethodsTwenty-five Wistar-Han rats were equally subdivided into 5 groups and initially received 8 injections on 4 consecutive days per week of either 3.6 mL/kg body weight saline (group I–III) or 1.8 mmol Gd/kg body weight gadobutrol (group IV) or gadodiamide (group V). T1- and T2-weighted scans, as well as relaxation maps, were acquired at 1 week (all groups); 5, 12, 20, and 26 weeks (saline II, gadobutrol, gadodiamide); and at 35, 44, and 52 weeks (saline III, gadobutrol, gadodiamide) after the last administration. Saline I was euthanized after 1 week, saline II after 26 weeks, and the remaining groups after 52 weeks. Signal intensities (SIs) were evaluated for the DCN/pons (P) and the GP/piriform cortex (PC) ratios, and relaxation times for the DCN and the GP. Brain tissue was extracted, and the gadolinium, iron, and manganese contents were quantified with inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation–ICP-MS imaging.ResultsT1-weighted SI ratios did not show any significant trend with age in any region. The between-group analysis at 52 weeks resulted in a significant difference for the DCN/P and GP/PC region ratio between gadodiamide and its comparators. T1 relaxation times dropped with increasing age in the GP with a 10% to 20% difference between first and last measurement for all groups, and in the DCN <10% with a significant decrease for the gadodiamide group only (DCN: P = 0.0158). Group-related differences were observed at the last measurement time point for T1 values between gadodiamide and saline III in the DCN (P = 0.0153) and gadodiamide and gadobutrol in the GP (P = 0.0287). Analysis of the SI ratios of the T2-weighted images revealed a significant increase for the DCN/P and a decrease for the GP/PC with increasing age for all groups and no differences at 52 weeks after the last injection between groups. T2 values of the GP showed a significant linear decrease over time for all groups (saline I–III: P = 0.0101; gadobutrol: P = 0.0001; gadodiamide: P = 0.0142) in the aging rat brain. Quantitative imaging of manganese and iron by laser ablation–ICP-MS showed a linear increase for the saline groups in the GP for both metals (Fe: P < 0.0001; Mn: P = 0.0306) and in the DCN for manganese only (P = 0.0187), but no differences between groups at 52 weeks.ConclusionsExtensive MRI evaluation did not reveal an indication of SI or relaxation time changes associated with multiple exposure to the macrocyclic-chelated GBCA gadobutrol in the DCN and the GP. With increasing age, a T1 and T2 shortening in the GP and an increase in T2-weighted SI ratio in the DCN/P, as well as a decrease in the GP/PC, were observed for all groups. Such age-related changes can potentially bias MRI results as an indicator for gadolinium presence in the brain.

Computed tomography (CT) and magnetic resonance imaging (MRI) of diffuse liver disease: a multiparametric predictive modelling algorithm can aid categorization of liver parenchyma.

Liver steatosis is common and tracking disease evolution to steatohepatitis and cirrhosis is essential for risk stratification and resultant patient management. Consequently, diagnostic tools allowing categorization of liver parenchyma based on routine imaging are desirable. The study objective was to compare established mono-factorial, dynamic single parameter and iterative multiparametric routine computed tomography (CT) and magnetic resonance imaging (MRI) analyses to distinguish between liver steatosis, steatohepatitis, cirrhosis and normal liver parenchyma. A total of 285 multi-phase contrast enhanced CT and 122 MRI studies with histopathological correlation of underlying parenchymal condition were retrospectively included. Parenchymal conditions were characterized based on CT Hounsfield units (HU) or MRI signal intensity (SI) measurements and calculated HU or SI ratios between non-contrast and contrast enhanced imaging time points. First, the diagnostic accuracy of mono-factorial analyses using established, static non-contrast HU and in- to opposed phase SI change cut-offs to distinguish between parenchymal conditions was established. Second, single dynamic discriminator analyses, with optimized non-contrast and enhancement HU and SI ratio cut-off values derived from the data, employing receiver operating characteristic (ROC) curve areas under the curve (AUCs) and the Youden index for maximum accuracy, were used for disease diagnosis. Third, multifactorial analyses, employing multiple non-contrast and contrast enhanced HU and SI ratio cut-offs in a nested, predictive-modelling algorithm were performed to distinguish between normal parenchyma, liver steatosis, steatohepatitis and cirrhosis. CT and MRI analyses were performed separately. No single CT or MRI parameter showed significant difference between all four parenchymal conditions (each P>0.05). Mono-factorial static-CT-discriminator analyses identified liver steatosis with 75% accuracy. Mono-factorial MRI analyses identified steatosis with 89% accuracy. Single-dynamic CT parameter analyses identified normal parenchyma with 72% accuracy and cirrhosis with 75% accuracy. Single-dynamic MRI parameter analyses identified fatty parenchyma with 90% accuracy. Multifactorial CT analyzes identified normal parenchyma with 84%, liver steatosis with 95%, steatohepatitis with 95% and cirrhosis with 80% accuracy. Multifactorial predictive modelling of MRI parameters identified normal parenchyma with 79%, liver steatosis with 89%, steatohepatitis with 92% and cirrhosis with 89% accuracy. Multiparametric analyses of quantitative measurements derived from routine CT and MRI, utilizing a predictive modelling algorithm, can help to distinguish between normal liver parenchyma, liver steatosis, steatohepatitis and cirrhosis.

Cytocompatible manganese dioxide-based hydrogel nanoreactors for MRI imaging

The application of nanoparticles in magnetic resonance imaging (MRI) has been greatly increasing, due to their advantageous properties such as nanoscale dimension and tuneability. In this context, manganese (Mn2+)-based nanoparticles have been greatly investigated, due to their valuable use as a contrast agent, improving signal intensity and specificity in MRI (manganese-enhanced MRI, MEMRI). Additionally, Mn2+ can act as scavengers of reactive oxygen species (ROS), commonly present in the inflammatory processes of neurodegenerative diseases. The aim of the present study was to develop nanoreactors, which can be used as contrast-agent in MEMRI. Several blends of methacrylated gellan gum (GG-MA) and hyaluronic acid (HA) were embedded with different types of manganese dioxide (MnO2) nanoparticles and further physico-chemically characterized. Dynamic light scattering, scanning electron microscopy, water uptake and degradation studies were performed. In vitro cytotoxicity of the different formulations was also evaluated using an immortalized rat fibroblast cell line L929, up to 72 h of culturing. Synthesized nanoparticles were obtained with an average size of 70 nm and round-shaped morphology. The stability of the different formulations of hydrogels was not affected by nanoparticles' concentration or HA ratio. The presence of synthesized MnO2 (MnO2_S) nanoparticles reduced hydrogels' cytocompatibility, whereas the commercially available type 1 (MnO2_C1) nanoparticles were less toxic to cells. Additionally, cell proliferation and viability were enhanced when a lower content of HA was present. Higher concentrations (75 and 100 ng/mL) of MnO2_S and MnO2_C1 nanoparticles did not negatively affected cell viability, whereas the opposite effect was observed for the commercial type 2 (MnO2_C2) nanoparticles. Further studies are required to evaluate the potential application of the most promising nanoreactors' formulations for combined application in MEMRI and as ROS scavengers.

Differentiation Between Primary Central Nervous System Lymphoma and Atypical Glioblastoma Based on MRI Morphological Feature and Signal Intensity Ratio: A Retrospective Multicenter Study

ObjectivesTo investigate the value of morphological feature and signal intensity ratio (SIR) derived from conventional magnetic resonance imaging (MRI) in distinguishing primary central nervous system lymphoma (PCNSL) from atypical glioblastoma (aGBM).MethodsPathology-confirmed PCNSLs (n = 93) or aGBMs (n = 48) from three institutions were retrospectively enrolled and divided into training cohort (n = 98) and test cohort (n = 43). Morphological features and SIRs were compared between PCNSL and aGBM. Using linear discriminant analysis, multiple models were constructed with SIRs and morphological features alone or jointly, and the diagnostic performances were evaluated via receiver operating characteristic (ROC) analysis. Areas under the curves (AUCs) and accuracies (ACCs) of the models were compared with the radiologists’ assessment.ResultsIncision sign, T2 pseudonecrosis sign, reef sign and peritumoral leukomalacia sign were associated with PCNSL (training and overall cohorts, P < 0.05). Increased T1 ratio, decreased T2 ratio and T2/T1 ratio were predictive of PCNSL (all P < 0.05). ROC analysis showed that combination of morphological features and SIRs achieved the best diagnostic performance for differentiation of PCNSL and aGBM with AUC/ACC of 0.899/0.929 for the training cohort, AUC/ACC of 0.794/0.837 for the test cohort and AUC/ACC of 0.869/0.901 for the overall cohort, respectively. Based on the overall cohort, two radiologists could distinguish PCNSL from aGBM with AUC/ACC of 0.732/0.724 for radiologist A and AUC/ACC of 0.811/0.829 for radiologist B.ConclusionMRI morphological features can help differentiate PCNSL from aGBM. When combined with SIRs, the diagnostic performance was better than that of radiologists’ assessment.

1D magnetic resonance imaging and low-field nuclear magnetic resonance relaxometry of water-based silica nanofluids

The purpose of this research is to investigate 1-D Magnetic Resonance Imaging (MRI) and low-field Nuclear Magnetic Resonance (NMR) relaxation characteristics of silica nanofluids. The results show that presence of silica nanoparticles increases the MRI signal intensity and influences the NMR relaxation by shifting the relaxation peaks toward faster times compared to deionized water (DIW). Additionally, inversion recovery sequences show that nanoparticles reduce longitudinal relaxation time. For the tested nanofluid of EOR-12, signal intensity, longitudinal relaxation rate and transverse relaxation rate show a strong linear dependence on nanoparticle concentration with the highest enhancement of 1.75-fold, 2.57-fold and 3.20-fold, respectively compared to DIW. Additionally, investigation of the effect of nanoparticle size shows that below an optimal size, the MRI signal intensity and the NMR relaxation rates show a positive correlation with nanoparticle size but above the optimal size, the behavior reverses. For the nanoparticle with the optimal diameter, signal intensity, longitudinal relaxation rate and transverse relaxation rate enhancement was 2.21-fold, 4.44-fold and 4.45-fold, respectively compared to DIW. Application of the observed improvement in signal intensity to obtain the profile of the aqueous phase volume fraction in a Pickering emulsion shows a maximum error of 8% which indicates that the proposed technique can be applied for emulsion characterization with good accuracy.

Fabricating Dual-Functional Plasmonic-Magnetic Au@MgFe2O4 Nanohybrids for Photothermal Therapy and Magnetic Resonance Imaging.

Bifunctional nanohybrids possessing both plasmonic and magnetic functionalities are of great interest for biomedical applications owing to their capability for simultaneous therapy and diagnostics. Herein, we fabricate a core–shell structured plasmonic–magnetic nanocomposite system that can serve as a dual-functional agent due to its combined photothermal therapeutic and magnetic resonance imaging (MRI) functions. The photothermal activity of the hybrid is attributed to its plasmonic Au core, which is capable of absorbing near-infrared (NIR) light and converting it into heat. Meanwhile, the magnetic MgFe2O4 shell exerts its ability to act as a MRI contrast agent. Our in vivo studies using tumor-bearing mice demonstrated the nanohybrids’ excellent photothermal and MRI properties. As a photothermal therapeutic agent, the nanohybrids were able to dramatically shrink solid tumors in mice through NIR-induced hyperthermia. As T2-weighted MRI contrast agents, the nanohybrids were found capable of substantially reducing the MRI signal intensity of the tumor region at 10 min postinjection. With their dual plasmonic–magnetic functionality, these Au@MgFe2O4 nanohybrids hold great promise not only in the biomedical field but also in the areas of catalysis and optical sensing.

The value of quantitative magnetic resonance imaging signal intensity in distinguishing between spinal meningiomas and schwannomas.

Background: Prior studies have suggested a number of the subjective visual characteristics that help distinguish between spinal meningiomas and schwannomas on magnetic resonance imaging and computed tomography; however, objective quantification of the signal intensity can be useful information. This study assessed whether quantitative magnetic resonance imaging (MRI) signal intensity (SI) measurements could distinguish intradural-extramedullary schwannomas from meningiomas.Methods: From July 2019 to September 2021, 54 patients with intradural-extramedullary tumors (37 meningiomas and 17 schwannomas) underwent surgery, and tumors were verified pathologically. Defined regions of interest were used to quantify SI values on T1- (T1W) and T2-weighted images (T2W). Receiver operating characteristic curve analysis was used to obtain cutoff values and calculate the area under the curve (AUC), sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV).Results: Both Maximum (T2max) and mean (T2mean) T2W SI values demonstrated outstanding (AUC: 0.91) abilities to differentiate meningiomas from schwannomas with Se, Sp, PPV, and NPV values of 94.6%, 70.6%, 87.5%, and 85.7%, respectively, for T2max and 81.1%, 88.2%, 93.8%, and 68.2% for T2mean. The maximum SI value on contrast-enhanced T1W (T1CEmax) and the T2W tumor: fat SI ratio (rTF) demonstrated acceptable abilities (AUC: 0.73 and 0.79, respectively) to differentiate meningiomas from schwannomas with Se, Sp, PPV, and NPV values of 94.6%, 70.6%, 87.5%, and 85.7%, respectively, for T1CEmax and 81.1%, 88.2%, 93.8%, and 68.2% for rTF.Conclusions: Quantitative SI values (T2max, T2mean, T2min, T1CEmax, rTF) can be used to differentiate intradural-extramedullary schwannomas from meningiomas.

The limbus in developmental dysplasia of the hip: An obstacle to reduction and its images changed by the femoral head position.

This study aimed to describe the shape of the limbus arthroscopically and via arthrogram and magnetic resonance imaging (MRI), and to determine whether it prevents concentric reduction of the femoral head in developmental dysplasia of the hip (DDH).Twelve patients (mean age, 10.2 months; range, 3–31 months) who underwent arthroscopic-assisted reduction for DDH were retrospectively reviewed. Limbus shapes were captured on arthrogram before reduction, after closed reduction, and after arthroscopic-assisted reduction and categorized according to the Miyake classification.On arthrogram, the superior limbus was blocked in 2 hips, inverted in 2, intermediate in 5, and everted in 3 after attempted closed reduction. After arthroscopic-assisted reduction, the limbus was everted in 7 hips and normal in 5. On arthroscopy, in all cases, the limbus appeared as a whitish, cartilage-like ring with a variably blunted edge before reduction, without inversion or eversion. On postoperative MRI, 10 of 12 superior limbi showed hypertrophy or globular compression by the femoral head with intermediate or mixed MRI signal intensities and blunted edges. The remaining 2 hips had hypertrophied superior limbi with sharp edges. On transverse plane MRI, the posterior limbus of all hips showed sharp margins with low MRI signal intensity. Residual subluxation was observed in 7 of the 12 hips with interposition of the anteroinferior limbus.The appearance of the limbus varied according to the femoral head position, and it was neither inverted nor everted. Interposed anteroinferior limbi with residual subluxation suggest impeded concentric reduction in DDH.

Preoperative Magnetic Resonance Imaging Signal Intensity Classification Is Associated With Clinical Presentation and Surgical Outcomes in Myelopathy Caused by Thoracic Ossification of Ligamentum Flavum: A Multicenter Study.

Retrospective Cohort Study. To explore whether classification of the increased signal intensity (ISI) on magnetic resonance imaging (MRI) correlates with clinical presentations and outcomes in symptomatic thoracic ossification of ligamentum flavum (T-OLF) patients. All patients with symptomatic T-OLF who underwent laminectomy at four institutions were reviewed. The ISI on preoperative T2-weighted MRI was divided into 3 groups, Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). Neurological function before surgery and at follow-up was evaluated by the revised Japanese Orthopedic Association (JOA) score. Patients' demographics, clinical manifestations, and surgical outcomes were compared. A total of 94 patients were involved. Preoperative MRI showed 32 patients in Grade 0, 39 patients in Grade 1, and 23 patients in Grade 2. Low extremities numbness, weakness, and clinical signs were less frequent in Grade 0 patients. The grade of ISI was correlated with the duration of symptoms and cord compression. Grade 0 patients had a better preoperative JOA score than those with ISI changes, while Grade 2 patients showed worse neurological recovery, longer duration of operation, more intraoperative blood loss, and a higher incidence of perioperative complications. The classification of ISI is an effective parameter for preoperatively assessing cord compression, clinical severity, and surgical outcomes in T-OLF patients. Grade 0 patients have relatively mild neurological impairment but are more likely to be misdiagnosed. Grade 2 indicates the worst clinical impairment and neurological recovery, and implies a risky and challenging surgery.

Repeatability and Reproducibility of ADC Measurements and MRI Signal Intensity Measurements of Bone Marrow in Monoclonal Plasma Cell Disorders: A Prospective Bi-institutional Multiscanner, Multiprotocol Study.

Apparent diffusion coefficient (ADC) and signal intensity (SI) measurements play an increasing role in magnetic resonance imaging (MRI) of monoclonal plasma cell disorders. The purpose of this study was to assess interrater variability, repeatability, and reproducibility of ADC and SI measurements from bone marrow (BM) under variation of MRI protocols and scanners. Fifty-five patients with suspected or confirmed monoclonal plasma cell disorder were prospectively included in this institutional review board-approved study and underwent several measurements after the standard clinical whole-body MR scan, including repeated scan after repositioning, scan with a second MRI protocol, scan at a second 1.5 T scanner with a harmonized MRI protocol, and scan at a 3 T scanner. For T1-weighted, T2-weighted STIR, B800 images, and ADC maps, regions of interest were placed in the BM of the iliac crest and sacral bone, and in muscle tissue for image normalization. Bland-Altman plots were constructed, and absolute bias, relative bias to mean, limits of agreement, and coefficients of variation were calculated. Interrater variability and repeatability experiments showed a maximal relative bias of -0.077 and a maximal coefficient of variation of 16.2% for all sequences. Although the deviations at the second 1.5 T scanner with harmonized MRI protocol to the first 1.5 T scanner showed a maximal relative bias of 0.124 for all sequences, the variation of the MRI protocol and scan at the 3 T scanner led to large relative biases of up to -0.357 and -0.526, respectively. When comparing the 3 T scanner to the 1.5 T scanner, normalization to muscle reduced the bias of T1-weighted and T2-weighted sequences, but not of ADC maps. The MRI scanners with identical field strength and harmonized MRI protocols can provide relatively stable quantitative measurements of BM ADC and SI. Deviations in MRI field strength and MRI protocol should be avoided when applying ADC cutoff values, which were established at other scanners or when performing multicentric imaging trials.

A regenerative 3D scaffold for inguinal hernia repair. MR imaging and histological cross evidence. Qualitative study

BackgroundInguinal hernia is a degenerative disease occurring in a high motile surround. Stopping degeneration and promoting tissue regeneration should be the treatment goal. Groin hernias are conventionally managed with static flat meshes, mostly fixated to the delicate inguinal environment. Far from a regenerative effect, the biologic response of conventional hernia meshes is characterized by a foreign body reaction leading to a stiff/shrunken scar plate, which is often the source of unpleasant complications. Recently, a newly engineered 3D device for inguinal hernia repair – ProFlor-has been developed to produce a regenerative biological response. Unlike conventional hernia meshes, this regenerative 3D hernia scaffold seems to demonstrate suitable features for a pathogenetical and physiological coherent treatment of the disease. The aim of this manuscript is to cross evidence these features through magnetic resonance imaging (MRI) and histology. Study designThe biological response of ProFlor at three defined post-implantation stages has been evaluated through MRI signal intensity and compared to neighbouring muscles and fat. As additional proof, histology of tissue specimens excised at the same post-implantation periods from porcine models during an experimental attempt were also evaluated. ResultsMRI of newly ingrown tissue in ProFlor demonstrated similar signal intensity of muscles while fat tissue showed remarkably higher values. These data matched with the histology of ProFlor biopsies excised from pigs. ConclusionsThe motile compliance to groin movements of ProFlor appears to induce a probiotic biologic response comparable to a regenerative scaffold, allowing to physiologically resolve the degenerative source of inguinal hernia disease.

Aneurysm risk metrics and hemodynamics are associated with greater vessel wall enhancement in intracranial aneurysms.

Vessel wall enhancement (VWE) in contrast-enhanced magnetic resonance imaging (MRI) is a potential biomarker for intracranial aneurysm (IA) risk stratification. In this study, we investigated the relationship between VWE features, risk metrics, morphology and hemodynamics in 41 unruptured aneurysms. We reconstructed the IA geometries from MR angiography and mapped pituitary stalk-normalized MRI intensity on the aneurysm surface using an in-house tool. For each case, we calculated the maximum intensity (CRstalk) and IA risk (via size and the rupture resemblance score (RRS)). We performed correlation analysis to assess relationships between CRstalk and IA risk metrics (size and RRS), as well as each parameter encompassed in RRS, i.e. aneurysmal size ratio (SR), normalized wall shear stress (WSS) and oscillatory shear index. We found that CRstalk had a strong correlation (Pearson correlation coefficient, PCC = 0.630) with size and a moderate correlation (PCC = 0.472) with RRS, indicating an association between VWE and IA risk. Furthermore, CRstalk had a weak negative correlation with normalized WSS (PCC = −0.320) and a weak positive correlation with SR (PCC = 0.390). Local voxel-based analysis showed only a weak negative correlation between normalized WSS and contrast-enhanced MRI signal intensity (PCC = −0.240), suggesting that if low-normalized WSS induces enhancement-associated pathobiology, the effect is not localized.