MRI Visualization Research Articles

MRI Accurately Visualizes RF Ablation Delivery Targeted to MRI-Defined Arrhythmia Substrates in the Left Ventricle.

Investigate the capacity of MRI to evaluate efficacy of radiofrequency (RF) ablations delivered to MRI-defined arrhythmogenic substrates. Baseline MRI was performed at 3T including 3D LGE in a swine model of chronic myocardial infarct (N=8). MRI-derived maps of scar and heterogeneous tissue channels (HTCs) were generated using ADAS 3D. Animals underwent electroanatomic mapping and ablation of the left ventricle in CARTO3, guided by MRI-derived scar maps. Post-ablation MRI (in vivo at 3T in 5/8 animals; ex vivo at 1.5T in 3/8) included 3D native T1-weighted IR-SPGR (TI=700-800ms) to visualize RF lesions. T1-derived RF lesions were compared against excised tissue. The locations of T1-derived RF lesions were compared against CARTO ablation tags, and segment-wise sensitivity and specificity of lesion detection were calculated within the AHA 17-segment model. RF lesions were clearly visualized in HTCs, scar, and myocardium. Ablation patterns delivered in CARTO matched T1-derived RF lesion patterns with high sensitivity (88.9%) and specificity (94.7%), and were closely matched in registered MR-EP data sets, with a displacement of 5.4 ±3.8mm (N=152 ablation tags). Integrating MRI into ablative procedures for RF lesion assessment is feasible. Patterns of RF lesions created using a standard 3D EAM system are accurately reflected by MRI visualization in healthy myocardium, scar, and HTCs comprising the MRI-defined arrhythmia substrate. MRI visualization of RF lesions can provide near-immediate (<24h) assessment of ablation, potentially indicating whether critical MRI-defined ventricular tachycardia substrates have been adequately ablated.

Solvent Effects in Hyperpolarization of 15N Nuclei in [15N3]Metronidazole and [15N3]Nimorazole Antibiotics via SABRE‐SHEATH**

AbstractMetronidazole and nimorazole are antibiotics of a nitroimidazole group which also may be potentially utilized as hypoxia radiosensitizers for the treatment of cancerous tumors. Hyperpolarization of 15N nuclei in these compounds using SABRE‐SHEATH (Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei) approach provides dramatic enhancement of detection sensitivity of these analytes using magnetic resonance spectroscopy and imaging. Methanol‐d4 is conventionally employed as a solvent in SABRE hyperpolarization process. Herein, we investigate SABRE‐SHEATH hyperpolarization of isotopically labeled [15N3]metronidazole and [15N3]nimorazole in nondeuterated methanol and ethanol solvents. Optimization of such hyperpolarization parameters as polarization transfer magnetic field, temperature, parahydrogen flow rate and pressure allowed us to obtain an average 15N polarization of up to 7.2–7.4 % for both substrates. The highest 15N polarizations were observed in methanol‐d4 for [15N3]metronidazole and in ethanol for [15N3]nimorazole. At a clinically relevant magnetic field of 1.4 T the 15N nuclei of these substrates possess long characteristic hyperpolarization lifetimes (T1) of ca. 1 to ca. 7 min. This study represents a major step toward SABRE in more biocompatible solvents, such as ethanol, and also paves the way for future utilization of these hyperpolarized nitroimidazoles as molecular contrast agents for MRI visualization of tumors.

Quantitative MRI post-processing algorithm and visualization research based on moisture status detection of winter jujube

Quantitative Magnetic Resonance Imaging (qMRI) offers precise measurements of the relaxation characteristics of microstructures, representing a cutting-edge method in non-destructive fruit analysis. This study aims to visualize information on changes in moisture status and distribution at the subcellular level of winter jujube. The 0.5 T nuclear magnetic imaging equipment was utilized to rapidly, non-invasively, and accurately capture the internal relaxation status of the sample with multiple-echo-imaging. By examining the signal and noise data, a simulated dataset was developed to tackle the optimization challenge of estimating parameters for the discrete relaxation model from the multiple-echo-imaging data, especially under conditions of low signal-to-noise ratio (SNR) and in the context of heteroscedastic noise. An optimal weighting factor and the T2NR truncation model have been identified to establish an effective experimental inversion strategy. Subsequently, multiple-echo-imaging can rapidly and stably yielded voxel-level maps under conditions of low signal-to-noise ratio. Utilizing this experimental approach, data from winter jujube was collected and analyzed, facilitating an exploration of water activity (T2 mapping) and associated water content (A2 mapping). Through analyzing winter jujube fruits across two maturity stages, this study elucidates the role of precise quantification and voxel-wise visualization in moisture status detection. The methodology presents an innovative approach for assessing internal moisture distribution in fruits.

Preclinical evaluation of transaxial intraputaminal trajectory for enhanced distribution of grafted cells in Parkinson's disease.

The objective of this study was to develop and evaluate the feasibility and safety of a novel transaxial surgical approach for the delivery of human induced pluripotent stem cell-derived dopaminergic neuroprogenitor cells (DANPCs) into the putamen nucleus using nonhuman primates and surgical techniques and tools relevant to human clinical translation. Nine immunosuppressed, unlesioned adult cynomolgus macaques (4 females, 5 males) received intraputaminal injections of vehicle or DANPCs (0.9 × 105 to 1.1 × 105 cells/µL) under real-time intraoperative MRI guidance. The infusates were combined with 1-mM gadoteridol (for intraoperative MRI visualization) and delivered via two tracks per hemisphere (ventral and dorsal) using a transaxial approach. The total volumes of infusion were 25 µL and 50 µL for the right and left putamen, respectively (infusion rate 2.5 µL/min). Animals were evaluated with a battery of clinical and behavioral outcome measures and euthanized 7 or 30 days postsurgery; full necropsies were performed by a board-certified veterinary pathologist. Brain tissues were collected and processed for immunohistochemistry, including against the human-specific marker STEM121. The optimized surgical technique and tools produced successful targeting of the putamen via the transaxial approach. Intraoperative MR images confirmed on-target intraputaminal injections in all animals. All animals survived to scheduled termination without clinical evidence of neurological deficits. The first 4 animals to undergo surgery had mild brain swelling noted at the end of surgery, of which 3 had transient reduced vision; administration of mannitol therapy and reduced intravenous fluid during the surgical procedure addressed these complications. Immunostaining against STEM121 confirmed the presence of grafted cells along the injection track within the targeted putamen area of DANPC-treated animals. All adverse histological findings were limited in scope and consistent with surgical manipulation, injection procedure, and postsurgical inflammatory response to the mechanical disruption caused by the cannula insertion. The delivery system, injection procedure, and DANPCs were well tolerated in all animals. Prevention of mild brain swelling by mannitol dosing and reduction of intravenous fluids during surgery allowed visual effects to be avoided. The results of the study established that this novel transaxial approach can be used to correctly and safely target cell injections to the postcommissural putamen and support clinical investigation.

Digital Light Processing of 19F MRI-Traceable Gelatin-Based Biomaterial Inks towards Bone Tissue Regeneration.

Gelatin-based photo-crosslinkable hydrogels are promising scaffold materials to serve regenerative medicine. They are widely applicable in additive manufacturing, which allows for the production of various scaffold microarchitectures in line with the anatomical requirements of the organ to be replaced or tissue defect to be treated. Upon their in vivo utilization, the main bottleneck is to monitor cell colonization along with their degradation (rate). In order to enable non-invasive visualization, labeling with MRI-active components like N-(2,2-difluoroethyl)acrylamide (DFEA) provides a promising approach. Herein, we report on the development of a gelatin-methacryloyl-aminoethyl-methacrylate-based biomaterial ink in combination with DFEA, applicable in digital light processing-based additive manufacturing towards bone tissue regeneration. The fabricated hydrogel constructs show excellent shape fidelity in line with the printing resolution, as DFEA acts as a small molecular crosslinker in the system. The constructs exhibit high stiffness (E = 36.9 ± 4.1 kPa, evaluated via oscillatory rheology), suitable to serve bone regeneration and excellent MRI visualization capacity. Moreover, in combination with adipose tissue-derived stem cells (ASCs), the 3D-printed constructs show biocompatibility, and upon 4 weeks of culture, the ASCs express the osteogenic differentiation marker Ca2+.

Abstract PO2-23-04: Magnetic Seeds, used to Locate the Metastatic Axillary Lymph Node placed before Neoadjuvant Chemotherapy for Breast Cancer Treatment, do not interfere the pre-surgical MRI Breast response assessment

Abstract Background: Axillary management in clinically node-positive patients who converted to ycN0 after neoadjuvant chemotherapy (NAC) for breast cancer (BC) remains under research with the aim of de-escalation of axillary lymph node dissection (ALND). A magnetic seed is one of the several positive lymph nodes marking techniques used in targeted axillary dissection (TAD) for patients with cN1 breast cancer undergoing neoadjuvant systemic therapy. It has been criticized for its potential masking effect due to the artefact it produces in the MRI sequences used to assess a proper breast response. This study evaluates if the magnetic seeds placed before NAC for guided TAD have influenced in the breast MRI response assessments. Methods: From October 2021 to June 2023, patients with cT0-4 cN1 breast cancer who were candidates for primary systemic treatment were prospectively recruited. Once a breast lesion and axillary node positivity were confirmed, a based hydrogel marker and a magnetic seed, respectively, were placed prior NAC. Once systemic treatment was completed, imaging techniques were used to assess the response, with MRI being the imaging technique of choice to assess breast response and axillary ultrasound the imaging technique of choice to assess axillary response. Surgical pathological confirmation of response in the axilla was by TAD, including sentinel lymph node and magnetic clipped node resection. Results: A total of 43 patients were included and their characteristics are shown in Table 1. In 16 patients (37%) the tumour was located in the upper outer quadrant (UOQ). In this group, the susceptibility artefact produced by the magnetic seed in the MRI created a black hole obscuring the axilla with a mean diameter of 69 mm (range: 57-76 mm). In no case did the halo interfere with the correct MRI visualisation of the breast marker. By MRI, the mean distance of the artifact halo from the breast marker or residual breast lesion was 40 mm (range: 13-79 mm). Overall, complete radiological response (ycCR) was reported in 20 patients (46%), breast only in 21 (49%) and axilla only in 38 (88%) patients. In 5 patients, preoperative axillary ultrasound revealed residual axillary disease, confirmed by FNA, lead to direct ALND. In the remaining 38 patients the axillary TAD assessment was completed. In all cases, the magnetic clipped node was successfully surgically removed. Pathological complete response (pCR) was confirmed in 9 (21%), breast only in 11 (26%) and axilla only in 13 (30%) patients. MRI diagnostic performance in detecting residual breast disease after NAC was not altered by the magnetic clipped node artifact when comparing the tumour location in the UOQ to the other quadrants (AUC 0.764 vs. 0.702; p=0.698). Conclusions: Surgical axillary staging remains the most reliable method for assessing the axillary response after NAC. Target axillary dissection guided by magnetic seed placed before NAC is an effective and accurate technique. The artifact generated in the MRI does not interfere with the pre-surgical breast response assessment after neoadjuvant systemic treatment. Table 1: Patients and tumor characteristics Citation Format: Martin Espinosa-Bravo, Joaquin Rivero Deniz, Clara Morales Comas, Javier de la Torre Fernandez de Vega, Irene Vives Rosello, Enrica Esposito, Vicente Peg Camara, María De Les Neus Rus Calafell, Ignacio Miranda Gomez, Christian Siso Raber. Magnetic Seeds, used to Locate the Metastatic Axillary Lymph Node placed before Neoadjuvant Chemotherapy for Breast Cancer Treatment, do not interfere the pre-surgical MRI Breast response assessment [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-23-04.

CMR 3-107 - Fully Automated Inline 4D Flow MRI Visualization and Flow Quantification

CMR 3-107 - Fully Automated Inline 4D Flow MRI Visualization and Flow Quantification

CTNI-28. FINAL RESULTS OF A PILOT STUDY TO EVALUATE INFUSION RATE ESCALATION TO MAXIMIZE VOLUME OF DISTRIBUTION DURING CONVECTION ENHANCED DELIVERY TO CONTRAST-ENHANCING GLIOBLASTOMA

Abstract BACKGROUND Volume of distribution (Vd) during convection enhanced delivery is impacted by the characteristics of the tissue being treated. For Glioblastoma (GBM), Vd is substantially higher in non-contrast enhancing tumor than in contrast enhancing tumor due to higher infusate efflux in enhancing tumor. We hypothesized that increasing the infusion rate could overcome the infusate efflux rate in enhancing tumor to improve the Vd to volume of infusion (Vi) ratio and provide better tumor coverage. METHODS A single center, IRB-approved pilot study was conducted under an IND (held by MAV) to perform rate escalated delivery of Topotecan with Gadolinium-DTPA to contrast-enhancing recurrent GBM (rGBM). A single Cleveland Multiport Catheter was surgically placed into enhancing tumor and then a 4-hour infusion was performed with real-time MRI visualization. Intra- and inter-patient rate escalation was performed. RESULTS 3 patients with rGBM were enrolled and treated. The initial infusion rate for patient 1 was 5 microliters/minute per microcatheter (4 total) and the final infusion rate for the third patient was 20 microliters/minute per microcatheter. We observed partial backflow at this rate and so did not escalate higher. There was coverage of both enhancing and non-enhancing tumor in all cases, and the Vd/Vi ratio ranged from 0.7 to 1.3. Patients tolerated the treatments well; there were no CTCAE Grade 3 or higher treatment related adverse events. CONCLUSIONS The higher efflux rate associate with contrast-enhancing tumor tissue can be overcome with sufficient infusion rate escalation.

MRI visualization of aortic recoarctation in the long-term period after surgery (case report)

Case study. Aortic coarctation refers to well-known and well-studied congenital malformations of the cardiovascular system. The success of cardiovascular surgery significantly increased the survival rate of patients, but, unfortunately, did not reduce the risks of serious cardiovascular complications in the long-term postoperative period. One of the significant complications remains recoarctation – repeated narrowing in the area of surgery, which can initiate other complications.The purpose of the study: to present the features of blood flow in the aorta in a patient with aortic coarctation in the long-term postoperative period on the clinical example of a complex MR examination.Material and methods. A 12-year-old patient, at the age of 6, she underwent balloon angioplasty of aortic coarctation. Echocardiographic data revealed a residual gradient at the isthmus of the aorta and expansion of the descending aorta. To clarify the diagnosis, MRI angiography of the heart was performed with intravenous contrast and the use of a cardiopackage for 4D flow analysis (4D flow).Results and discussion. According to the MRI study, a narrowing of the distal aortic arch with aortic dilation after the departure of the left subclavian artery was revealed, which is confirmed by the obtained absolute values of blood flow indicators. MR-angiography of the aortic arch made it possible to visually determine the “gothic” shape of the aortic arch and present 3D reconstructions. 4D flow maps showed acceleration of blood flow to the systole in the area of aortic narrowing, additional vortex flow below the area of aortic narrowing and spiral flow in the descending aorta, which persisted throughout the diastole.One explanation for the abnormal spiral flow in the descending thoracic aorta may be the presence of a “gothic” aortic arch. Also, residual hypoplasia of the aortic arch and narrowing of the isthmus are the leading parameters affecting the pathophysiology of changes in blood pressure during exercise.Conclusion. The 4D-flow MR package in vivo makes it possible to study the flow geometry and blood flow parameters in detail, to obtain a detailed picture of the aortic condition, which gives potential advantages in a comprehensive examination of patients with aortic coarctation under dynamic observation.

Single low-dose INC280-loaded theranostic nanoparticles achieve multirooted delivery for MET-targeted primary and liver metastatic NSCLC

BackgroundNon-small cell lung cancer (NSCLC) patients with primary tumors and liver metastases have substantially reduced survival. Since mesenchymal-epithelial transition factor (MET) plays a significant role in the molecular mechanisms of advanced NSCLC, small molecule MET inhibitor capmatinib (INC280) hold promise for clinically NSCLC treatment. However, the major obstacles of MET-targeted therapy are poor drug solubility and off-tumor effects, even oral high-dosing regimens cannot significantly increase the therapeutic drug concentration in primary and metastatic NSCLC.MethodsWe developed a multirooted delivery system INC280-PFCE nanoparticles (NPs) by loading INC280 into perfluoro-15-crown-5-ether for improving MET-targeted therapy. Biodistribution and anti-MET/antimetastatic effects of NPs were validated in orthotopic NSCLC and NSCLC liver metastasis models in a single low-dose. The efficacy of INC280-PFCE NPs was also explored in human NSCLC specimens.ResultsINC280-PFCE NPs exhibited excellent antitumor ability in vitro. In orthotopic NSCLC models, sustained release and prolonged retention behaviors of INC280-PFCE NPs within tumors could be visualized in real-time by 19F magnetic resonance imaging (19F-MRI), and single pulmonary administration of NPs showed more significant tumor growth inhibition than oral administration of free INC280 at a tenfold higher dose. Furthermore, a single low-dose INC280-PFCE NPs administered intravenously suppressed widespread dissemination of liver metastasis without systemic toxicity. Finally, we verified the clinical translation potential of INC280-PFCE NPs in human NSCLC specimens.ConclusionsThese results demonstrated high anti-MET/antimetastatic efficacies, real-time MRI visualization and high biocompatibility of NPs after a single low-dose.

Pore-Scale Investigation of CH4 Hydrate Kinetics in Clayey-Silty Sediments by Low-Field NMR

Clayey-silty sandy media have been widely discovered in naturally occurring hydrate-bearing sediments in the South China Sea. However, the phase change behavior of CH4 hydrate (MH) and the resulting pore structure change and the migration of fluid in clayey-silty sediments remain less known and warrant investigation. In this study, we examine the pore-scale behavior of MH formation and dissociation in clayey-silty sediments and the associated fluid migration by low-field nuclear magnetic resonance (NMR). Based on T2 spectra measurement, MH starts to grow in small pores (pore size <1 μm) first and in large pores (pore size >10 μm) subsequently. The presence of clay, i.e., Na-MMT, practically retards the overall growth kinetics of MH evidenced by the low H2O conversion (<10%) to MH in clay-associated small pores. During depressurization, MH starts to dissociate in sand-associated large pores first. Free water migrates to clay-associated small pores and partially converts to clay-bound water. MRI visualization depicts the heterogeneous spatial distribution of both MH and the residual water in the process. The experimental results provide possible explanations on the spatial heterogeneity of MH in clay-silty sediments in nature and on the multiphase fluid migration during energy recovery from MH reservoirs.

Clinical outcome of imaging-based programming for anterior thalamic nucleus deep brain stimulation.

The authors hypothesized that the proximity of deep brain stimulator contacts to the anterior thalamic nucleus-mammillothalamic tract (ANT-MMT) junction determines responsiveness to treatment with ANT deep brain stimulation (DBS) in drug-resistant epilepsy and conducted this study to test that hypothesis. This retrospective study evaluated patients who had undergone ANT DBS electrode implantation and whose devices were programmed to stimulate nearest the ANT-MMT junction based on direct MRI visualization. The proximity of the active electrode to the ANT and the ANT-MMT junction was compared between responders (≥ 50% reduction in seizure frequency) and nonresponders. Linear regression was performed to assess the percentage of seizure reduction and distance to both the ANT and the ANT-MMT junction. Four (57.1%) of 7 patients had ≥ 50% reduction in seizures. All 4 responders had at least one contact within 1 mm of the ANT-MMT junction, whereas the 3 patients with < 50% seizure improvement did not have a contact within 1 mm of the ANT-MMT junction. Additionally, the 4 responders demonstrated contact positioning closer to the ANT-MMT junction than the 3 nonresponders (mean distance from MMT: 0.7 mm on the left and 0.6 mm on the right in responders vs 3.0 mm on the left and 2.3 mm on the right in nonresponders). However, proximity of the electrode contact to any point in the ANT nucleus did not correlate with seizure reduction. Greater seizure improvement was correlated with a contact position closer to the ANT-MMT junction (R2 = 0.62, p = 0.04). Seizure improvement was not significantly correlated with proximity of the contact to any ANT border (R2 = 0.24, p = 0.26). Obtained using a combination of direct visualization and targeted programming of the ANT-MMT junction, data in this study support the hypothesis that proximity to the ANT alone does not correlate with seizure reduction in ANT DBS, whereas proximity to the ANT-MMT junction does. These findings support the importance of direct targeting in ANT DBS, as well as imaging-informed programming. Additionally, the authors provide supportive evidence for future prospective trials using ANT-MMT junction for direct surgical targeting.

29. Imaging outcome at 24-month follow-up in a prospective, multicenter study of two-level cervical arthroplasty with a PEEK on ceramic artificial disc

<h3>BACKGROUND CONTEXT</h3> The use of cervical total disc replacement (cTDR) continues to increase. The implants continually evolve with respect to design and materials. Imaging studies of these devices provides insight to their ability to provide and maintain range of motion (ROM), disc height, and depending on the implant materials, facet joint assessment. <h3>PURPOSE</h3> The purpose of this study was to evaluate the imaging outcome of a PEEK-on-ceramic artificial disc for the treatment of two-level cervical disc disease. <h3>STUDY DESIGN/SETTING</h3> Data for this study came from a prospective, multicenter, non-randomized, historically controlled FDA Investigational Device Exemption (IDE) trial evaluating the Simplify®Cervical Artificial Disc for use at two levels. <h3>PATIENT SAMPLE</h3> Two-level cTDR was performed in 182 patients treated for symptomatic cervical disc degeneration with radiculopathy/myelopathy. <h3>OUTCOME MEASURES</h3> The primary outcome measures were ROM, disc height, and heterotopic ossification (HO) of the treated levels. MRI was used to assess the facet joints. <h3>METHODS</h3> The cTDR is composed of PEEK endplates with a mobile ceramic core. Radiographic evaluations were performed preoperatively, at hospital discharge, and 6 weeks, and 3, 6, 12, and 24 months postoperatively. MRI was performed pre- and 24 months postoperatively. All images were evaluated by an independent core lab. HO was evaluated based on a 0 (normal) to 4 (bridging bone) scale. Facets joints were scored on a 4-point scale ranging from 0 (normal) to 3 (severe degeneration) based on the MRI performed pre- and 24 months postoperatively. <h3>RESULTS</h3> At the superior cTDR level, the mean ROM improved from 8.0° prior to surgery to 9.5° at 24-month follow-up. At the inferior level, the values were 6.6° and 8.9°, respectively. At both operated levels, mean disc height increased postoperatively and the increase was maintained through 24-month follow-up. At the superior index level, the preoperative mean height was 3.1 mm and at 24 months it was 4.3 mm. At the inferior index level, the preoperative height was 3.1 mm and was 4.0 at 24 months. HO rates at 24-month follow-up were, the superior index level, severe HO (Grade 3) occurred in 8 patients (5%). Bridging HO (Grade 4) was also seen in 8 patients (5%). At the inferior index level, severe and bridging HO was seen in 17 (10%) and 5 (3%) patients, respectively. There was a lack of facet degeneration progression assessed on MRI between pre- and 24-month follow-up. No patient had severe facet degeneration at either operated level at either time point. The percentage of patients with a grade of moderate facet degeneration did not change at either level 8% at the superior index level and 5% at the inferior index level. At both levels, there appeared to be patients changing from the "none" category to the "mild" category. At the superior level prior to surgery, the figures for "none" and "mild" were 62% and 30% respectively. At 24-month follow-up, the figures were 52% and 39%, respectively. A similar pattern was seen at the inferior index level. <h3>CONCLUSIONS</h3> This study adds to the expanding evidence that two-level cTDR increases and maintains ROM and disc height and through 24-month follow-up. The majority of cTDR patients did not experience bridging HO. This PEEK-on-ceramic cTDR produces minimal artifact, allowing for reliable MRI visualization. This was used to evaluate the facet joints and a lack of facet degeneration progression was found. <h3>FDA DEVICE/DRUG STATUS</h3> Simplify Cervical Artificial Disc 2-level (Approved for this indication).

Virtual cadaver facilitates abdominopelvic anatomy teaching

Purpose CT imaging of the upper abdomen has complex anatomy that can be difficult to parse given similar densities of multiple organs. Understanding of upper abdominal anatomy, limitations of CT imaging, and alternative methods for visualization are important for physicians in multiple surgical and non-surgical fields. We repurposed a novel, open-access resource to facilitate teaching upper abdominal anatomy. Methods This pilot study with medical students had three learning objectives: 1) identify abdominal organs and sub-structures on CT and 3D human cadaver imaging 2) justify why different types of contrast (e.g. oral or IV) are used or can be omitted based on region of interest. 3) Rationalize use of non-CT visualizations such as MRI, endoscopy, or laparotomy for select scenarios. Hybrid in-person and virtual attendance at sessions employing CT images linked with human cadaver image set serially sectioned from Visible Human Project (https://www.nlm.nih.gov/research/visible/visible_human.html). Students identified and outlined structures on CT using three orthogonal planes prior to blending in cadaver images. Facilitated discussion of challenging organ interfaces (e.g. pancreas and duodenum) and techniques to improve contrast or alternative visualization modalities (e.g. MRI or direct visualization). Post-session survey delivered via e-mail same day. Results Seven students attended the pilot session (3 virtually) with five of seven responding to survey (71% response rate). All respondents found the session to be moderately or very helpful and felt that after the session they were moderately or very confident in their ability to identify upper abdominal structures. Regarding the cadaver images, 1 student thought it was very helpful (20%), 3 students thought it was moderately helpful (60%), and 1 student thought it was not at all helpful (20%). Discussion Human cadaver imaging can help facilitate teaching of CT based anatomy in a pilot study of medical students. Additional sessions may better elucidate benefits and limitations. This resource could be adapted for residents identifying hepatobiliary structures, distinguishing prostate apex from genitourinary diaphragm, and differentiating mediastinal nodal levels from vascular spaces. CT imaging of the upper abdomen has complex anatomy that can be difficult to parse given similar densities of multiple organs. Understanding of upper abdominal anatomy, limitations of CT imaging, and alternative methods for visualization are important for physicians in multiple surgical and non-surgical fields. We repurposed a novel, open-access resource to facilitate teaching upper abdominal anatomy. This pilot study with medical students had three learning objectives: 1) identify abdominal organs and sub-structures on CT and 3D human cadaver imaging 2) justify why different types of contrast (e.g. oral or IV) are used or can be omitted based on region of interest. 3) Rationalize use of non-CT visualizations such as MRI, endoscopy, or laparotomy for select scenarios. Hybrid in-person and virtual attendance at sessions employing CT images linked with human cadaver image set serially sectioned from Visible Human Project (https://www.nlm.nih.gov/research/visible/visible_human.html). Students identified and outlined structures on CT using three orthogonal planes prior to blending in cadaver images. Facilitated discussion of challenging organ interfaces (e.g. pancreas and duodenum) and techniques to improve contrast or alternative visualization modalities (e.g. MRI or direct visualization). Post-session survey delivered via e-mail same day. Seven students attended the pilot session (3 virtually) with five of seven responding to survey (71% response rate). All respondents found the session to be moderately or very helpful and felt that after the session they were moderately or very confident in their ability to identify upper abdominal structures. Regarding the cadaver images, 1 student thought it was very helpful (20%), 3 students thought it was moderately helpful (60%), and 1 student thought it was not at all helpful (20%). Human cadaver imaging can help facilitate teaching of CT based anatomy in a pilot study of medical students. Additional sessions may better elucidate benefits and limitations. This resource could be adapted for residents identifying hepatobiliary structures, distinguishing prostate apex from genitourinary diaphragm, and differentiating mediastinal nodal levels from vascular spaces.

Mitochondria-specific gadolinium (III) porphyrinate as efficient ROS generator for MRI visualization and sonodynamic-immunotherapy of deep localized tumors

Conventional sonodynamic therapy (SDT) is still limited in conquering localized tumors owing to its low reactive oxygen species (ROS)-based therapeutic effect and undesirably inhibiting effect of immunosuppressive tumor microenvironment (ITM). In this study, we reasonably designed a new sonosensitizer, gadolinium (III) porphyrinate (GdPorP), which could efficiently produce ROS upon ultrasound irradiation and specifically accumulate in mitochondria. The GdPorP-based mitochondria-specific sonodamage could induce high-efficiency cell apoptosis and cascade to producing large-scale immunogenic cell death. After GdPorP systematically delivered together with the indoleamine 2,3-dioxygenase (IDO) inhibitor by a pH-sensitive nanomedicine, the localized liver tumor was specifically mapped by the “switching-on” MRI. And the nanomedicine could not only efficiently suppress the progression of primary liver tumors but also simultaneously boost the systematic antitumor immune effect via the inhibition of ITM. The GdPorP-approved sonodynamic-immunotherapy (SDIT) has thereby been established as a new paradigm for upgrading the efficacy of cancer SDT.

Dexamethasone does not affect endolymphatic hydrops (EH) in patients with Meniere's disease within 24 h, and intratympanic administration of gadolinium plus dexamethasone simplifies high-quality imaging of EH using a novel protocol of 7 min

BackgroundIntratympanic administration of gadolinium chelate allows for a better visualization of endolymphatic hydrops (EH) using MRI than intravenous injection and was recently further improved to facilitate high-quality imaging of EH in 7 min. The aim of the present study was to simplify the intratympanic administration protocol by mixing gadolinium chelate with therapeutic dexamethasone and to evaluate the effects of this mixture on the visualization of EH in MRI. Materials and methodsIn an in vitro study, the potential impact of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) on the stability of dexamethasone was evaluated by analyzing dynamic changes in dexamethasone with high-performance liquid chromatography (HPLC) after mixing with Gd-DTPA. Ten patients with definite Meniere's disease (MD) were recruited to study the potential interference of dexamethasone on MRI visualization of EH, and 49 patients with MD were recruited to evaluate the effect of intratympanic injection of Gd-DTPA mixed with dexamethasone on MRI of EH using a 3T MR machine and a novel heavily T2-weighted 3-dimensional fluid-attenuated inversion recovery reconstructed using a magnitude plus zero-filled interpolation (hT2FLAIR-MZFI) sequence. ResultsThe retention times and peak area of dexamethasone in HPLC were not modified by the addition of Gd-DTPA. EH grading in the cochlea and vestibule was not influenced in any ear by intratympanic injection of dexamethasone. Excellent inner ear images were obtained from all patients, and EHs with various grades were displayed. There were significant correlations between diagnosis and cochlear EH (p < 0.01, Spearman's Rho), between diagnosis and vestibular EH (p < 0.01, Spearman's Rho), and between cochlear and vestibular EH (p < 0.01, Spearman's Rho). The distribution of Gd-DTPA plus dexamethasone negatively correlated with the grade of vestibular EH. Injury of the endolymph-perilymph barrier was detected in one cochlea and three vestibules of 59 inner ears with MD. ConclusionsIntratympanic administration of Gd-DTPA plus dexamethasone yielded high-quality MRI images of EH in patients with MD using a novel 7-min protocol and simplified the clinical application. Intratympanic administration of Gd-DTPA plus dexamethasone might be used to test its therapeutic effect in future work. Level of evidence3.

Olfactory dysfunction and olfactory bulb volume in patients with deviated nasal septum

The purpose of the study is to demonstrate the possibility and information content of olfactory bulb volume measuring in healthy volunteers and patients with deviated nasal septum, as well as the relationship between the volume of the olfactory bulb and olfactory function. Material and methods. 28 men with deviated nasal septum aged 24 to 35 years (main group) and 21 clinically healthy volunteers, men aged 23 to 33 years (control group) were examined. All patients underwent checkup of the ENT organs and examinations on a 1.5 T MRI machine with 12-channel head coil. The sense of smell was examined using the extended Sniffin Sticks test (SST) (“Buerhard”, Hamburg, Germany) with the definition of 3 parameters: threshold, identification and discrimination. Results. In accordance with the design of the work, threshold, discrimination, identification subtests and MRI examination of the head were performed with the measurement of the olfactory bulb volume of patients in the main group and volunteers in the control group. In all participants in the control group was diagnosed normosmia in accordance with the TDI indicator, and in patients with deviated nasal septum – hyposmia. Olfactory function in patients deviated nasal septum was significantly lower on the narrower side as indicated for odor thresholds, odor recognition, and odor identification (P&lt;0.01). It was found that olfactory bulb volumes are larger on the wider side than on the narrower side (P&lt;0.01). Conclusion. Asymmetry in the size and volume of OB is observed only in patients with deviated nasal septum, it is absent in healthy volunteers. MRI visualization and morphometry of olfactory bulb, in addition to identifying of the nasal cavity, paranasal sinuses state, are informative in the process of preoperative examination of patients with deviated nasal septum. Olfactory bulb volume definition should be used for personalized diagnosis and quantitative assessment of olfactory dysfunction.

Review on Hybrid Segmentation Methods for Identification of Brain Tumor in MRI.

Modalities like MRI give information about organs and highlight diseases. Organ information is visualized in intensities. The segmentation method plays an important role in the identification of the region of interest (ROI). The ROI can be segmented from the image using clustering, features, and region extraction. Segmentation can be performed in steps; firstly, the region is extracted from the image. Secondly, feature extraction performed, and better features are selected. They can be shape, texture, or intensity. Thirdly, clustering segments the shape of tumor, tumor has specified shape, and shape is detected by feature. Clustering consists of FCM, K-means, FKM, and their hybrid. To support the segmentation, we conducted three studies (region extraction, feature, and clustering) which are discussed in the first line of this review paper. All these studies are targeting MRI as a modality. MRI visualization proved to be more accurate for the identification of diseases compared with other modalities. Information of the modality is compromised due to low pass image. In MRI Images, the tumor intensities are variable in tumor areas as well as in tumor boundaries.

MRI Visualization and Distribution Patterns of Foreign Modeling Agents: A Brief Pictorial Review for Clinicians.

Since the ancient Egyptians, people have always been worried about their physical appearance. Nowadays, for some cultures like Latin American, physical appearance depends on the context, and the concept of beauty is to have wider hips and more prominent buttocks. One way to achieve these goals is to inject foreign modelants that include some oils to modify certain body regions. Until today, the search continues to find a modelling agent that is nonteratogenic, noncarcinogenic, and not susceptible to infection and can stay at the spot where it was injected (not migration). This review is aimed at providing a brief, comprehensive assessment of the use of modeling agents and summarizes some key imaging features of filler-related complications. The topics of this review are historical data, epidemiology, classification of dermal fillers (xenografts, hyaluronic acid derivatives, autografts, homografts, synthetic materials), adverse reactions, imaging method used in the detection of injectable fillers, MRI patterns observed in complications of injectable fillers, and histological findings of immune response, treatment, and conclusions. We present several classifications of injectable fillers based on composition, degradation, and complications. Additionally, readers will find some representative cases of the most common locations of injectable fillers demonstrating their infiltrative MRI patterns.

A literature review of magnetic resonance imaging sequence advancements in visualizing functional neurosurgery targets.

Historically, preoperative planning for functional neurosurgery has depended on the indirect localization of target brain structures using visible anatomical landmarks. However, recent technological advances in neuroimaging have permitted marked improvements in MRI-based direct target visualization, allowing for refinement of "first-pass" targeting. The authors reviewed studies relating to direct MRI visualization of the most common functional neurosurgery targets (subthalamic nucleus, globus pallidus, and thalamus) and summarize sequence specifications for the various approaches described in this literature. The peer-reviewed literature on MRI visualization of the subthalamic nucleus, globus pallidus, and thalamus was obtained by searching MEDLINE. Publications examining direct MRI visualization of these deep brain stimulation targets were included for review. A variety of specialized sequences and postprocessing methods for enhanced MRI visualization are in current use. These include susceptibility-based techniques such as quantitative susceptibility mapping, which exploit the amount of tissue iron in target structures, and white matter attenuated inversion recovery, which suppresses the signal from white matter to improve the distinction between gray matter nuclei. However, evidence confirming the superiority of these sequences over indirect targeting with respect to clinical outcome is sparse. Future targeting may utilize information about functional and structural networks, necessitating the use of resting-state functional MRI and diffusion-weighted imaging. Specialized MRI sequences have enabled considerable improvement in the visualization of common deep brain stimulation targets. With further validation of their ability to improve clinical outcomes and advances in imaging techniques, direct visualization of targets may play an increasingly important role in preoperative planning.