CT Magnetic Resonance Imaging Research Articles

Low-field MRI study of the 1H distribution and migration in porous sediments during natural gas conversion from methane hydrate

Gas hydrates, crystalline compounds formed from water and guest molecules like methane, are gaining attention as a promising clean energy source. While research has extensively focused on the extraction and transport of natural gas hydrates from offshore marine sediments, the dynamic processes in the porous sediments remain under explored. This study employs low-field Magnetic Resonance Imaging (MRI) to investigate the in-situ formation and dissociation of methane hydrate within a partially saturated stack of glass beads. By integrating advanced MRI techniques, including 1D dhk SPRITE, bulk T1 distribution, and 2D spatial T2 imaging, this research provides a comprehensive analysis of fluid distribution and migration during phase transitions in the porous sediments. Three key findings emerged from the study. First, SE-SPI measurements successfully quantified hydrate and residual water saturation, aligning with previous X-ray CT and high-field MRI studies and validating low-field MRI for hydrate research. Secondly, this study introduced a volumetric approach to T1 and T2 measurements, distinguishing between free and bound water, with characteristic relaxation times for each, confirming the technique's capability to differentiate types of residual water. Finally, spatially resolved T2 relaxation time distributions revealed vertical fluid migration within the pore spaces, identifying an equilibrium zone where inflow and outflow rates were balanced. Overall, this study underscores the effectiveness of low-field MRI as a noninvasive tool for analyzing hydrate-bearing sediments. The findings lay the groundwork for further exploration of hydrate in porous sediments, enhancing our understanding of gas production dynamics in hydrate-rich environments.

PDOC-13 ACCESS TO CARE OF CHILD DIAGNOSED WITH PINEOBLASTOMA AND NURSING CHALLENGES TO ADDRESS THE NEEDS ARISE

Abstract Patient Alu (not her real name) was 8 years old girl when diagnosed with Pineoblastoma causing obstructive hydrocephalus. Presented initial at Primary health care with headache,photophobia,lethargic and vomiting for two weeks. CT scan and MRI(Magnetic resonance imaging) were done on arrival to our care and revealed Pineal region tumour. Biopsy were done. Radiotherapy,surgery,chemotherapy including rehabilitation were planned by Multidisciplinary team. This case study focus on the access of care needs of this patient and the family with an emphasis on the Nurses challenges to address those needs. Medical records were retrospectively reviewed for this Patient from June 2021 on the onset of presenting symptoms and initial admission in Redcross War Memorial Children’s Hospital at Cape Town South Africa up to March 2024 last admission in Hospital. Found that were levels of unmet needs some areas of difficulty are not discussed, some areas family feels difficult to explain or mention such as emotional burnout, language, cultural, spritual and schooling etc. In view of all this Nurses may focus on supporting families on discharge and during admission, working better relationship with Primary health care, appropriate referrals for counseling for coping mechanism. Financial constrains is still a major issue throughout.

Gd-EOB-DTPA-enhanced MRI proves advantageous in selecting surgical candidates for patients with early-stage hepatocellular carcinoma: An analysis in terms of oncological outcomes

Background and aimsTo determine the value of preoperative Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in comparison with extracellular contrast agent MRI and CT in the selection of surgical candidates among patients with hepatocellular carcinoma (HCC), particularly in terms of oncological outcomes after hepatectomy. MethodsThis retrospective study included 542 consecutive patients who underwent radical hepatectomy for HCC. One group underwent preoperative Gd-EOB-DTPA-enhanced MRI, one group underwent contrast-enhanced CT, and one group underwent extracellular contrast agent MRI. We compared oncologic outcomes including recurrence free survival and overall survival between the three groups. Subgroup analyses were also performed to provide more specific candidates or beneficiaries for preoperative EOB-MRI. ResultsA total of 244 patients had tumor recurrence, with 55 in the EOB-MRI group, 106 in the Routine-MRI group, and 83 in the CT group (p = 0.010). The numbers with early recurrence (<2 years) in each group were 40 (27.03%), 78 (35.78%), and 62 (35.22%), respectively (p = 0.018). The 1, 2, and 3-year recurrence-free survival (RFS) percentages were 82.4%, 73.0%, and 68.2% in the EOB-MRI group, 70.2%, 64.3%, and 56.9% in the Routine-MRI group, and 76.8%, 64.83%, and 58.9% in the CT group (p = 0.010). The 1, 2, and 3-year overall survival percentages were 89.19%, 83.11%, and 80.41% in the EOB-MRI group, 79.82%, 73.86%, and 67.44% in the Routine-MRI group, and 86.55%, 76.14%, and 69.32% in the CT group (p = 0.016). Subgroup analysis showed significant differences in RFS in patients with solitary tumor <3 cm. ConclusionPreoperative EOB-MRI is superior to contrast-enhanced CT or extracellular contrast agent MRI for selecting surgical candidates at low risk of recurrence following hepatic resection for HCC.

Structural phenotyping in atrial fibrillation with combined cardiac CT and atrial MRI: Identifying and differentiating individual structural remodelling types in AF.

Atrial remodelling (AR) is the persistent change in atrial structure and/or function and contributes to the initiation, maintenance and progression of atrial fibrillation (AF) in a reciprocal self-perpetuating relationship. Left atrial (LA) size, geometry, fibrosis, wall thickness (LAWT) and ejection fraction (LAEF) have all been shown to vary with pathological atrial remodelling. The association of these global remodelling markers with each other for differentiating structural phenotypes in AF is not well investigated. Patients referred for first-time AF ablation and controls without AF were prospectively recruited to undergo cardiac computed tomographic angiography (CCTA) and magnetic resonance imaging (MRI) with 3D atrial late-gadolinium enhanced (LGE) sequences. LAWT, atrial myocardial mass, LA volume and sphericity were calculated from CT. Biplane LA EF and LA fibrosis burden were derived from atrial MRI. Results were compared between patients with AF and controls. Forty two AF patients (64.3% male, age 64.6 ± 10.2 years, CHA2DS2-VASc 2.48 ± 1.5, 69.0% paroxysmal AF, 31% persistent AF, LVEF 57.9 ± 10.5%) and 37 controls (64.9% male, age 56.6 ± 7.2, CHA2DS2-VASc 1.54 ± 1.1, LVEF 60.4 ± 4.9%) were recruited. Patients with AF had a significantly higher LAWT (1.45 ± 0.52 mm vs 1.12 ± 0.42 mm, p = 0.003), tissue mass (15.81 ± 6.53 g vs. 12.18 ± 5.01 g, p = 0.011), fibrosis burden (9.33 ± 8.35% vs 2.41 ± 3.60%, p = 0.013), left atrial size/volume (95.68 ± 26.63 mL vs 81.22 ± 20.64 mL, p = 0.011) and lower LAEF (50.3 ± 15.3% vs 65.2 ± 8.6%, p < 0.001) compared to controls. There was no significant correlation between % fibrosis with LAWT (p = 0.29), mass (p = 0.89), volume (p = 0.49) or sphericity (p = 0.79). LAWT had a statistically significant weak positive correlation with LA volume (r = 0.25, p = .041), but not with sphericity (p = 0.86). LAEF had a statistically significant but weak negative correlation with fibrosis (r = -0.33, p = 0.008) and LAWT (r = -0.24, p = 0.07). AF is associated with significant quantifiable structural changes that are evident in LA size, tissue thickness, total LA tissue mass and fibrosis. These individual remodelling markers do not or only weakly correlate with each other suggesting different remodelling subtypes exist (e.g. fibrotic vs hypertrophic vs dilated). If confirmed, such a detailed understanding of the structural changes observed has the potential to inform clinical management strategies targeting individual mechanisms underlying the disease process.

Single-Stage Press-Fit Osseointegration of the Radius and Ulna for Rehabilitation After Trans-Forearm Amputation.

Upper limb (UL) amputation is disabling. ULs are necessary for many domains of life1, and few effective motor and sensory replacements are accessible2. Approximately 41,000 people in the United States have UL amputation proximal to the fingers3, two-thirds of (all) traumatic amputations are UL4, and 80% of UL amputations are performed for trauma-related etiologies5. Socket prosthesis (SP) abandonment remains high because of the lack of sensation, limited prosthesis control, perceived weight, and difficulty comfortably wearing the SP6. Transcutaneous osseointegration7,8 surgically inserts a bone-anchored implant, passed through a transcutaneous portal to attach a terminal device, improving amputee rehabilitation by reducing perceived weight, conferring osseoperception9, and increasing wear time10. Without the socket, all residual skin and musculature remain available for transcutaneous myoelectrodes. The present article describes single-stage radius and ulna press-fit osseointegration (PFOI) after trans-forearm amputation. This technique resembles a lower-extremity PFOI11,12. Importantly, at-risk nerves and vessels are different, and implant impaction must be gentler as a result. The surgery is indicated for patients who are dissatisfied with SP rehabilitation or declining alternative rehabilitative options, and who are motivated and enabled to procure, train with, and utilize a forearm prosthesis. An engaged prosthetist is critical. Surgical steps are exposure, bone-end and canal preparation, first implant insertion (in the operative video shown, in the radius), purse-string muscle closure, confirmation that radius-ulna motion remains, performing the prior steps for the other bone (in the video, the ulna), and closure (including potential nerve reconstruction, soft-tissue contouring, and portal creation). Although the patient in the operative video did not require nerve procedures to address pain or to create targets for transcutaneous myoelectrodes, targeted muscle reinnervation or a regenerative peripheral nerve interface procedure could be performed following exposure. Alternatives include socket modification, bone lengthening and/or soft-tissue contouring13, Krukenberg-type reconstructions14, or accepting the situation. An alternative implant is a screw-type osseointegration implant. Our preference for press-fit implants is based on considerations such as our practice's 12-year history of >1,000 PFOI surgeries; that the screw-type implant requires sufficient cortical thickness for the threads15, which is compromised in some patients; the lower cost per implant; that the procedure is performed in 1 instead of 2 surgical episodes15,16; and the documented suitability of press-fit implants for patients with challenging anatomy or comorbidities17-19. PFOI can be provided for amputees having difficulty with socket wear. PFOI usually provides superior prosthesis stability, which can confer better prosthesis control versus nonoperative and other operative options in patients expressing dissatisfaction for reasons such as those mentioned above, or for poor fit, compromised energy transfer, skin pinching, compression, and abrasions. For patients who want myoelectric control of their prosthesis but who are unable because the optimal myoelectric location is obstructed by the socket, osseointegration may provide access for the electrodes by eliminating the socket. Only 3 trans-forearm osseointegration20-22 publications totaling 10 limbs could be identified, limiting the ability to determine generalizable outcomes. Osseointegrated prostheses, being skeletally anchored, feel lighter to patients than SPs, which should confer better outcomes. In 1 patient, multiple implant fractures and infection prompted additional surgeries. Periprosthetic bone fractures and non-infectious loosening have not been documented for UL osseointegration. Osseointegration eliminates the socket, relieving socket-based pain. However, neurogenic pain relief requires specific nerve procedures.Osseointegration provides a prosthesis connection. Nerve- or muscle-based prosthesis control requires separate, potentially integrated planning.Osseointegrated prostheses confer osseoperception (i.e., mechanical force transmission), not "normal" skin-mediated afferent sensation (i.e., light touch, temperature, pain) or native proprioception.Prostheses must be individualized to the patient's elbow flexion and radioulnar rotation. An attentive prosthetist must be ensured preoperatively.Achieving the demonstrated outcomes requires more therapy and retraining than walking with an osseointegrated lower-extremity prosthesis. Patients must expect at least several months of spending multiple hours daily engaging in self-directed rehabilitation.Prosthesis utilization decision aids23 may minimize non-beneficial surgeries. UL = upper limbSP = socket prosthesisPFOI = press-fit osseointegrationperi-pros fx = periprosthetic fractureMRI = magnetic resonance imagingCT = computed tomography.

Talocalcaneal Coalition Resection with Local Fat Grafting and Flatfoot Reconstruction.

Talocalcaneal (TC) coalitions typically present in the pediatric population with medial hindfoot and/or ankle pain and absent subtalar range of motion. Coalition resection with fat interposition is well described for isolated tarsal coalitions1,2; however, patients with concomitant rigid flatfoot may benefit from additional reconstructive procedures. To address this, we employ the surgical technique of TC resection with local fat grafting and flatfoot reconstruction. This procedure is described in 3 steps: (1) gastrocnemius recession and fat harvesting, (2) TC coalition resection with local fat interposition, and (3) peroneus brevis Z-lengthening and calcaneal lateral column lengthening osteotomy with allograft. A 3 to 4-cm posteromedial longitudinal incision is made at the distal extent of the medial head of the gastrocnemius muscle. The gastrocnemius tendon is identified, dissected free of surrounding tissue, and transected. Superficial fat is then harvested from this incision before wound closure. A 7-cm incision is made from the posterior aspect of the medial malleolus to the talonavicular joint. The neurovascular bundle and flexor tendons are dissected carefully from the surrounding tissue as a group and protected while the coalition is completely resected, and bone wax and the local fat are utilized at the resection site to prevent regrowth of the coalition. An approximately 7-cm incision is then made laterally and obliquely following the Langer lines and centered over the lateral calcaneus. The peroneal tendons are released from their sheaths, and the peroneus brevis is Z-lengthened. A calcaneal osteotomy is performed about 1.5 cm proximal to the calcaneocuboid joint and angled to avoid the anterior and middle subtalar facet joints. Two Kirschner wires are inserted retrograde across the calcaneocuboid joint, and the calcaneal osteotomy is opened. A trapezoid-shaped allograft bone wedge is impacted, and the Kirschner wires are advanced across into the calcaneus. The lengthened peroneus brevis tendon is repaired, and the wound is closed in a layered fashion. First-line treatment is nonoperative with orthotics and immobilization. Surgical options include coalition resection with or without calcaneal lengthening osteotomy, arthrodesis, or arthroereisis. Following coalition resection, various grafts can be utilized, including fat autografts, bone wax, or split flexor hallucis longus tendon3-6. This procedure addresses TC coalition with concomitant rigid flatfoot. Resection alone may increase subtalar motion but does not correct a flatfoot deformity. Historically, surgeons performed arthrodesis or arthroereisis, but these are rarely performed in young patients. In patients with coalitions involving >50% of the posterior facet or preexisting degenerative changes, arthrodesis may be indicated7. Patients can expect improvement in pain and function8-11. Previous investigators reported improved patient satisfaction, improved range of motion, clinical and radiographic hindfoot correction, and an improved American Orthopaedic Foot & Ankle Society hindfoot score at the time of final follow-up8,9. Carefully free the neurovascular bundle from the surrounding soft tissue so that it can be carefully retracted away from the area of coalition resection.Utilize the interval between the posterior tibialis and flexor digitorum longus tendons to approach the coalition.Expose the medial wall of the coalition and perform a careful resection that avoids inadvertently diverging into the body of the talus or calcaneus.Place a smooth lamina spreader into the resected area and gently open the subtalar joint to confirm complete coalition resection.Place 2 retrograde wires across the calcaneocuboid joint before performing the osteotomy. Without this step, up to 50% of cases experience calcaneocuboid subluxation and/or rotation after the lateral column lengthening12.To determine the size of the allograft, place a lamina spreader into the osteotomy site to measure the width.If present, rigid supination of the forefoot must be corrected with a medial cuneiform plantar-based closing osteotomy. AOFAS = American Orthopaedic Foot & Ankle SocietyFADI = Foot and Ankle Disability IndexMRI = magnetic resonance imagingCT = computed tomographyOR = operating roomK-wire = Kirschner wire.

Quantitative MRI approach in the preoperative evaluation of a rare large-mass abdominal GIST tumor

Gastrointestinal stromal tumors (GISTs) are rare cancers originating from the gastrointestinal tract's interstitial cells of Cajal. This study explores the utility of quantitative Magnetic Resonance Imaging (MRI), particularly volumetric lesion segmentation, in the preoperative evaluation of large-mass abdominal GISTs. MRI offers high-resolution imaging without ionizing radiation, which is crucial for oncology patients requiring repeated scans. Advanced semi-automatic segmentation techniques were employed in this study from different MRI sequences to enhance precision in tumor boundary delineation and volumetric analysis, and aid personalized surgical planning. In addition, this study demonstrates that using different clinical imaging protocols and comparing volumetric data from CT and various MRI sequences yields consistent results with minimal volumetric error. Finally, integrating MRI data into real-time surgical navigation systems underscored the synergy between radiology, surgical oncology, and computer science, improving tumor margin assessment and reducing recurrence risk. This approach highlights a pivotal shift towards technology-enhanced healthcare, promising better patient outcomes.

Assessment and validation of glottic motion using cone-beam CT and real-time cine MRI

PurposeThis study aimed to assess the margin for the planning target volume (PTV) using the Van Herk formula. We then validated the proposed margin by real-time magnetic resonance imaging (MRI).MethodsAn analysis of cone-beam computed tomography (CBCT) data from early glottic cancer patients was performed to evaluate organ motion. Deformed clinical target volumes (CTV) after rigid registration were acquired using the Velocity program (Varian Medical Systems, Palo Alto, CA, USA). Systematic (Σ) and random errors (σ) were evaluated. The margin for the PTV was defined as 2.5 Σ + 0.7 σ according to the Van Herk formula. To validate this margin, we accrued healthy volunteers. Sagittal real-time cine MRI was conducted using the ViewRay system (ViewRay Inc., Oakwood Village, OH, USA). Within the obtained sagittal images, the vocal cord was delineated. The movement of the vocal cord was summed up and considered as the internal target volume (ITV). We then assessed the degree of overlap between the ITV and the PTV (vocal cord plus margins) by calculating the volume overlap ratio, represented as (ITV∩PTV)/ITV.ResultsCBCTs of 17 early glottic patients were analyzed. Σ and σ were 0.55 and 0.57 for left–right (LR), 0.70 and 0.60 for anterior–posterior (AP), and 1.84 and 1.04 for superior–inferior (SI), respectively. The calculated margin was 1.8 mm (LR), 2.2 mm (AP), and 5.3 mm (SI). Four healthy volunteers participated for validation. A margin of 3 mm (AP) and 5 mm (SI) was applied to the vocal cord as the PTV. The average volume overlap ratio between ITV and PTV was 0.92 (range 0.85–0.99) without swallowing and 0.77 (range 0.70–0.88) with swallowing.ConclusionBy evaluating organ motion by using CBCT, the margin was 1.8 (LR), 2.2 (AP), and 5.3 mm (SI). The margin acquired using CBCT fitted well in real-time cine MRI. Given that swallowing during radiotherapy can result in a substantial displacement, it is crucial to consider strategies aimed at minimizing swallowing and related motion.

The Value of Amide Proton Transfer MRI in the Diagnosis of Malignant and Benign Urinary Bladder Lesions: Comparison With Diffusion-Weighted Imaging.

Conventional magnetic resonance imaging (MRI) has certain limitations in distinguishing between malignant and benign urinary bladder (UB) lesions. Amide proton transfer (APT) imaging may provide more diagnostic information than diffusion-weighted imaging (DWI) to distinguish between malignant and benign UB. To investigate the potential of APT imaging in the diagnosis of malignant and benign UB lesions and to compare its diagnostic efficacy with that of conventional DWI. Prospective. Eighty patients with UB lesions. A 3.0 T/turbo spin echo (TSE) T1-weighted and T2-weighted imaging, single-shot echo planar DWI, and three-dimensional TSE APT imaging. Patients underwent radical cystectomy or transurethral resection of the bladder lesions within 2 weeks after CT urography and MRI examination. APT signal intensity in UB lesions was quantified by the asymmetric magnetization transfer ratio (MTRasym). MTRasym and apparent diffusion coefficient (ADC) values were measured and compared between malignant and benign UB lesions. Kolmogorov-Smirnov test, Student's t test or Mann-Whitney U test, Spearman rank correlation coefficient, area under the receiver operating characteristic (ROC) curve (AUC), Delong test, and intraclass correlation coefficient (ICC). The significance threshold was set at P < 0.05. Thirty-two patients had pathologically confirmed benign UB lesions, including 2 bladder leiomyomas, 1 submucosal amyloidosis, 1 inflammatory myofibroblastic tumor, and 28 inflammatory lesions, and 48 patients had pathologically confirmed urothelial carcinoma. Urothelial carcinomas showed significantly higher MTRasym values (1.53% [0.74%] vs. 0.85% [0.23%]) and significantly lower ADC values (1.24 ± 0.34 × 10-3 mm2/s vs. 1.43 ± 0.22 × 10-3 mm2/s) than benign UB lesions. The MTRasym value (AUC = 0.928) was significantly better in differentiating urothelial carcinoma from benign UB lesions than the ADC value (AUC = 0.722). APT imaging may have value in discriminating malignant from benign UB lesions and has better diagnostic performance than DWI. 3 TECHNICAL EFFICACY: Stage 2.

Angiography with cone-beam CT versus contrast-enhanced MRI for living donor transplant imaging: Is MRI enough?

The purpose of this study is to compare the subjective and objective quality and confidence between conventional angiography with cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) for the preoperative evaluation of potential donors for living donor liver transplant. Seventeen patients undergoing preoperative donor evaluation for living donor liver transplantation that underwent angiography with CBCT and contrast-enhanced MRI for evaluation of hepatic vascular anatomy were included in the study. Four attending radiologists interpreted anonymized, randomized angiography with CBCT images and MRIs, rating the diagnostic quality and confidence of their interpretation (on a 3-point scale) for each element, as well as clinically relevant measurements. Overall, the readers rated the quality of angiography with CBCT to be higher than that of MRI (median [interquartile range] = 3 (2, 3) vs. 2 (1-3), p < 0.001) across all patients. Readers of angiography with CBCT had more confidence in their interpretations as an average of all elements evaluated than the MRI readers (3 (3) vs. 3 (2, 3), p < 0.001). When the same reader interpreted both MRI and CBCT, the right hepatic artery diameter (3.8 mm ± 0.72 mm vs. 4.5 mm ± 1.2 mm, p < 0.005) and proper hepatic artery diameter (4.43 mm ± 0.98 mm vs. 5.4 mm ± 1.05 mm, p < 0.003) were significantly different between MRI and CBCT. There was poor interrater reliability for determining segment IV arterial supply for both modalities (κ < 0.2). Angiography with CBCT provides higher subjective diagnostic quality and greater radiologist confidence than MRI. The difference in measurements between CBCT and MRI when the same reader reads both studies suggests CBCT adds additional information over MRI evaluation alone.

Brain tumor diagnosis using CT scan and MRI images based on a deep learning method based on VGG

Brain cancer is one of the most deadly forms of cancer today, and its timely and accurate diagnosis can significantly impact the patient’s quality of life. A computerized tomography scan (CT) and magnetic resonance imaging (MRI) of the brain is required to diagnose this condition. In the past, several methods have been proposed as a means of diagnosing brain tumors through the use of medical images. However, due to the similarity between tumor tissue and other brain tissues, these methods have not proven to be accurate. A novel method for diagnosing brain tumors using MRI and CT scan images is presented in this paper. An architecture based on deep learning is used to extract the distinguishing characteristics of brain tissue from tumors. The use of fusion images allows for more accurate detection of tumor types. In comparison with other approaches, the proposed method has demonstrated superior results.

Respiratory-Correlated 4-Dimensional Magnetic Resonance Fingerprinting for Liver Cancer Radiation Therapy Motion Management

The objective of this study was to develop a respiratory-correlated (RC) 4-dimensional (4D) imaging technique based on magnetic resonance fingerprinting (MRF) (RC-4DMRF) for liver tumor motion management in radiation therapy. Thirteen patients with liver cancer were prospectively enrolled in this study. k-space MRF signals of the liver were acquired during free-breathing using the fast acquisition with steady-state precession sequence on a 3T scanner. The signals were binned into 8 respiratory phases based on respiratory surrogates, and interphase displacement vector fields were estimated using a phase-specific low-rank optimization method. Hereafter, the tissue property maps, including T1 and T2 relaxation times, and proton density, were reconstructed using a pyramid motion-compensated method that alternatively optimized interphase displacement vector fields and subspace images. To evaluate the efficacy of RC-4DMRF, amplitude motion differences and Pearson correlation coefficients were determined to assess measurement agreement in tumor motion between RC-4DMRF and cine magnetic resonance imaging (MRI); mean absolute percentage errors of the RC-4DMRF-derived tissue maps were calculated to reveal tissue quantification accuracy using digital human phantom; and tumor-to-liver contrast-to-noise ratio of RC-4DMRF images was compared with that of planning CT and contrast-enhanced MRI (CE-MRI) images. A paired Student t test was used for statistical significance analysis with a P value threshold of .05. RC-4DMRF achieved excellent agreement in motion measurement with cine MRI, yielding the mean (± standard deviation) Pearson correlation coefficients of 0.95 ± 0.05 and 0.93 ± 0.09 and amplitude motion differences of 1.48 ± 1.06 mm and 0.81 ± 0.64 mm in the superior-inferior and anterior-posterior directions, respectively. Moreover, RC-4DMRF achieved high accuracy in tissue property quantification, with mean absolute percentage errors of 8.8%, 9.6%, and 5.0% for T1, T2, and proton density, respectively. Notably, the tumor contrast-to-noise ratio in RC-4DMRI-derived T1 maps (6.41 ± 3.37) was found to be the highest among all tissue property maps, approximately equal to that of CE-MRI (6.96 ± 1.01, P=.862), and substantially higher than that of planning CT (2.91 ± 1.97, P=.048). RC-4DMRF demonstrated high accuracy in respiratory motion measurement and tissue properties quantification, potentially facilitating tumor motion management in liver radiation therapy.

Quantitative differentiation of minimal-fat angiomyolipomas from renal cell carcinomas using grating-based x-ray phase-contrast computed tomography: An ex vivo study.

The differentiation of minimal-fat-or low-fat-angiomyolipomas from other renal lesions is clinically challenging in conventional computed tomography. In this work, we have assessed the potential of grating-based x-ray phase-contrast computed tomography (GBPC-CT) for visualization and quantitative differentiation of minimal-fat angiomyolipomas (mfAMLs) and oncocytomas from renal cell carcinomas (RCCs) on ex vivo renal samples. Laboratory GBPC-CT was performed at 40 kVp on 28 ex vivo kidney specimens including five angiomyolipomas with three minimal-fat (mfAMLs) and two high-fat (hfAMLs) subtypes as well as three oncocytomas and 20 RCCs with eight clear cell (ccRCCs), seven papillary (pRCCs) and five chromophobe RCC (chrRCC) subtypes. Quantitative values of conventional Hounsfield units (HU) and phase-contrast Hounsfield units (HUp) were determined and histogram analysis was performed on GBPC-CT and grating-based attenuation-contrast computed tomography (GBAC-CT) slices for each specimen. For comparison, the same specimens were imaged at a 3T magnetic resonance imaging (MRI) scanner. We have successfully matched GBPC-CT images with clinical MRI and histology, as GBPC-CT presented with increased soft tissue contrast compared to absorption-based images. GBPC-CT images revealed a qualitative and quantitative difference between mfAML samples (58±4 HUp) and oncocytomas (44±10 HUp, p = 0.057) and RCCs (ccRCCs: 40±12 HUp, p = 0.012; pRCCs: 43±9 HUp, p = 0.017; chrRCCs: 40±7 HUp, p = 0.057) in contrast to corresponding laboratory attenuation-contrast CT and clinical MRI, although not all differences were statistically significant. Due to the heterogeneity and lower signal of oncocytomas, quantitative differentiation of the samples based on HUp or in combination with HUs was not possible. GBPC-CT allows quantitative differentiation of minimal-fat angiomyolipomas from pRCCs and ccRCCs in contrast to absorption-based imaging and clinical MRI.

Minimally Invasive Transforaminal Lumbar Interbody Fusion with Expandable Cages.

Minimally invasive surgical transforaminal lumbar interbody fusion (MIS-TLIF) is an increasingly common procedure for the treatment of lumbar degenerative pathologies. The MIS-TLIF technique often results in less soft-tissue injury compared with the open TLIF technique, reducing postoperative pain and recovery time1-3. However, the narrow surgical aperture of this minimally invasive technique has increased the difficulty of interbody cage placement. Expandable cages were designed to improve ease of insertion, improve visualization around the cage on insertion, reduce neurological retraction and injury by passing the nerve root with the implant in a collapsed state, and enable better disc-height and lordosis restoration on expansion4. This procedure is performed with the patient under general anesthesia and in a prone position. The appropriate spinal level is identified with use of fluoroscopy, and bilateral paramidline approaches are made utilizing the Wiltse intermuscular approach. Pedicle screws are placed bilaterally. A pedicle-based retractor or tubular retractor is passed along the Wiltse plane, and bilateral inferior facetectomies are performed. A foraminotomy is performed, including a superior facetectomy on the side with compression of the exiting nerve root. A thorough discectomy with end-plate preparation is performed. The disc space is sized with use of trial components. The cage is then implanted with a pre-expansion height less than the trialed height and is expanded under fluoroscopy. After expansion, the cage is backfilled with allograft and local autograft. Finally, the rods are contoured and reduced bilaterally, followed by closure in a multilayered approach. Nonoperative alternatives to the minimally invasive TLIF technique include physical therapy or epidural corticosteroid injections. When surgical intervention is indicated, there are several approaches that can be utilized during lumbar interbody fusion, including the posterior, direct lateral, anterior, or oblique approaches5. Expandable cages are designed to be inserted in a collapsed configuration and expanded once placed into the interbody space. This design offers numerous potential advantages over static alternatives. The low-profile, expandable cages require less impaction during placement, minimizing iatrogenic end-plate damage. Additionally, expandable cages require less thecal and nerve-root retraction and provide a larger surface footprint once expanded. The MIS-TLIF technique has been shown to significantly reduce back pain, leg pain, and disability, and to significantly increase function, with most improvements observed after 12 months postoperatively. Patients may experience a 51% and 39% reduction in visual analogue pain scores and Oswestry Disability Index scores, respectively6. The results for expandable cages compared with traditional static cages in TLIF surgery require further study. The technique utilized during insertion and placement of interbody cages plays an important role in cage subsidence. To reduce the risk of cage subsidence, cages should be placed level with the end plate and in contact with the apophyseal ring anteriorly. Additionally, caution should be taken when expanding the cage to ensure that the cage is not overexpanded, which may also increase the risk of mechanical failure and intraoperative subsidence.It is critical to understand the flexibility of the disc space and the osseous quality of the patient in order to know how much expansion may be applied through the cage without subsidence.If bullet-type cages are utilized, the tip of the cage should cross midline of the vertebral body to avoid generating iatrogenic scoliosis.Spine bone density should be investigated preoperatively in at-risk patients in order to identify osteoporotic patients, who are at greater risk for subsidence and instrumentation failure.Although advances in device technology are welcomed, surgeons should maintain a strong focus on technique to reduce complications and improve clinical outcomes when utilizing expandable cages. TLIF = transforaminal lumbar interbody fusionMIS = minimally invasive surgeryALIF = anterior lumbar interbody fusionMRI = magnetic resonance imagingCT = computed tomographyPEEK = polyetheretherketoneAP = anterioposteriorEMG = electromyographyDVT = deep vein thrombosisPE = pulmonary embolusODI = Oswestry Disability IndexEXP = expandable.

MRI-based vertebral bone quality score compared to quantitative computed tomography bone mineral density in patients undergoing cervical spinal surgery.

The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was introduced as a bone quality marker in the lumbar spine. Prior studies showed that it could be utilized as a predictor of osteoporotic fracture or complications after instrumented spine surgery. The objective of this study was to evaluate the correlation between VBQ scores and bone mineral density (BMD) measured by quantitative computer tomography (QCT) in the cervical spine. Preoperative cervical CT and sagittal T1-weighted MRIs from patients undergoing ACDF were retrospectively reviewed and included. The VBQ score in each cervical level was calculated by dividing the signal intensity of the vertebral body by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images and correlated with QCT measurements of the C2-T1 vertebral bodies. A total of 102 patients (37.3% female) were included. VBQ values of C2-T1 vertebrae strongly correlated with each other. C2 showed the highest VBQ value [Median (range) 2.33 (1.33, 4.23)] and T1 showed the lowest VBQ value [Median (range) 1.64 (0.81, 3.88)]. There was significant weak to moderate negative correlations between and VBQ Scores for all levels [C2: p < 0.001; C3: p < 0.001; C4: p < 0.001; C5: p < 0.004; C6: p < 0.001; C7: p < 0.025; T1: p < 0.001]. Our results indicate that cervical VBQ scores may be insufficient in the estimation of BMDs, which might limit their clinical application. Additional studies are recommended to determine the utility of VBQ and QCT BMD to evaluate their potential use as bone status markers.

Using a Further Planning MRI after Neoadjuvant Androgen Deprivation Therapy Significantly Reduces the Radiation Exposure of Organs at Risk in External Beam Radiotherapy of Prostate Cancer.

Radiotherapy for prostate cancer is often preceded by neoadjuvant androgen deprivation therapy (ADT), which leads to a reduction in the size of the prostate. This study examines whether it is relevant for treatment planning to acquire a second planning magnetic resonance imaging (MRI) after ADT (=MRI 2) or whether it can be planned without disadvantage based on an MRI acquired before starting ADT (=MRI 1). The imaging data for the radiotherapy treatment planning of 17 patients with prostate cancer who received two planning MRIs (before and after neoadjuvant ADT) were analyzed as follows: detailed comparable radiation plans were created separately, each based on the planning CT scan and either MRI 1 or MRI 2. After ADT for an average of 17.2 weeks, the prostate was reduced in size by an average of 24%. By using MRI 2 for treatment planning, the V60Gy of the rectum could be significantly relieved by an average of 15% with the same coverage of the target volume, and the V70Gy by as much as 33% (compared to using MRI 1 alone). Using a second MRI for treatment planning after neoadjuvant ADT in prostate cancer leads to a significant relief for the organs at risk, especially in the high dose range, with the same irradiation of the target volume, and should therefore be carried out regularly. Waiting for the prostate to shrink after a few months of ADT contributes to relief for the organs at risk and to lowering the toxicity. However, the use of reduced target volumes requires an image-guided application, and the oncological outcome needs to be verified in further studies.

Optimization Ground Glass Opacities (GGO) Detection Using Multipixel Interpolation Techniques

Ground Glass Opacities (GGO) are a picture of abnormal lung conditions characterized by white or gray areas. This picture of GGO in the lungs could previously be detected based on the results of medical examinations such as Computerized Tomography (CT scan) and Magnetic Resonance Imaging (MRI) images of patients suffering from Covid-19. However, from the results of the examination, it can be seen that the CT scan and MRI images still have a noise level that is too high, causing difficulties in describing the distribution pattern of the GGO itself. The purpose of this study was to optimize the detection of GGO on MRI images using the Multipixel Interpolation technique. The detection process adopts several stages including image preprocessing, edge detection process, and gradient morphological segmentation. Image preprocessing is done to remove noise and improve the MRI input image. The edge detection process is carried out to detect lung organs automatically using the Canny method which is optimized with the multipixel interpolation technique. The final stage of the research is the segmentation process using a gradient morphology technique to see the spread of GGO in patients with Covid-19 contained in the MRI image. The results of this study present an overview of the GGO pattern with fairly good results. The results of the GGO pattern description will also measure the level of spread to see the severity of pneumonia. Based on the results presented, this research is useful as an alternative solution in the process of diagnosis and treatment of Covid-19 patients.&#x0D;

Pyrocarbon Disc Interposition Arthroplasty (PyroDisk) for the Treatment of Carpometacarpal Thumb Joint Osteoarthritis.

Preoperatively, review radiology images to confirm that the osteoarthritis is limited to the thumb CMC joint and that all appropriate tools for inserting the disc are available before beginning surgery. Next, the patient is placed with their arm on an arm rest. The CMC thumb joint is exposed via a dorsal longitudinal skin incision, sparing the dorsal radial nerve branches and the radial artery and accompanying venes. The capsule is opened with an H-incision. With 2 parallel cuts to the joint surface, the articular surfaces of the joint are removed. After resection of the articular joint surfaces, the residual width and height of the joint space after resection are measured. The central point in the joint surfaces is marked for the bone tunnels. With an awl, tunnels are created from the center of the joint surface to the proximal (trapezial bone) and distal (first metacarpal bone) and the dorsal side. The implant size is measured with the trial implants for correct size of the disc. A tendon strip of either APL (abductor pollicis longus) or FCR (flexor carpi radialis) tendon is harvested for use securing the disc. The disc is secured with the tendon strip from proximal through the trapezium, through the disc and distal through the first metacarpal, and is secured to itself at the trapezial bone. The position is checked under fluoroscopy. When the disc in the right position, the joint capsule and skin are closed and a plaster cast is applied with the thumb in abduction. Alternative treatments include hemitrapeziectomy without interposition; full trapeziectomy, with or without ligament reconstruction and/or tendon interposition; and joint resurfacing prostheses. The advantage of pyrocarbon disc interposition arthroplasty over other treatment options is the preservation of the STT joint1. Therefore, the procedure is minimally harming the surrounding anatomy despite open surgery and has a high success rate in reducing pain while preserving function and strength. The risk of complications is comparable with that of other CMC joint arthroplasty techniques. A relatively high survival rate has been reported at a mean follow-up of 7 years (range, 5 to 12 years). In cases of recurrent pain, all other surgical options remain possible ("no bridges are burned"). The main disadvantage is the cost of the disc. Our recent study of this technique showed good patient-reported outcomes, pain reduction, patient satisfaction, and preservation of strength and range of motion at a mean follow-up of 7 years1,2. The survival rate was 91%, with 3% failing as a result of disc dislocation. Other reasons of failure were STT osteoarthritis and pain without a specific cause. Preoperatively, make sure that only the CMC thumb joint has osteoarthritis and that the STT joint does not. In cases in which it is unclear whether the osteoarthritis is isolated to the CMC thumb joint, perform computed tomography to make certain10.Only a few millimeters of bone must be resected from the first metacarpal base and the distal trapezium. Both bone cuts must be made parallel to each other and perpendicular to the longitudinal axis of the first metacarpal bone.Bone tunnels must be exactly centered in the cut joint surfaces for proper implant positioning and to decrease the chance of subluxation.Size the implant properly and check movement and stability. OR = operating roomFCR = flexor carpi radialisAPL = abductor pollicis longusPRWHE = Patient-Rated Wrist and Hand EvaluationDASH = Disabilities of the Arm, Shoulder and Hand QuestionnaireMHQ = Michigan Hand QuestionnaireROM = range of motionFU = follow-upCRPS = complex regional pain syndromeLRTI = ligament reconstruction and tendon interpositionMRI = magnetic resonance imagingCT = computed tomography.

The Value of CT Perfusion Parameters and Apparent Diffusion Coefficient Value of Magnetic Resonance Diffusion Weighted Imaging in Diagnosis of Hepatocellular Carcinoma.

Background Hepatocellular carcinoma is one of the malignant tumors with the highest incidence in the world. According to the latest statistics of the National Cancer Center, the incidence of liver cancer ranks fifth in malignant tumors and its mortality rate ranks second in China, which seriously threatens people' s life and health. Aim To investigate the value of CT perfusion parameters and apparent diffusion coefficient (ADC) of magnetic resonance imaging (MRI) diffusion weighted imaging (DWI) in the diagnosis of hepatocellular carcinoma. Methods 43 patients with hepatocellular carcinoma and 40 patients with hepatic hemangioma treated in our hospital from August 2018 to August 2021 were selected for CT perfusion imaging and MRI examination. Results The liver blood flow (BF), liver blood volume (BV), and hepatic artery perfusion (HAP) in the hepatocellular carcinoma group were (267.38 ± 35.59) ml/(min·100 g), (30.20 ± 8.82) ml/100 g, and (0.64 ± 0.10) ml/(min·ml), respectively, which were significantly higher than those in the hepatic hemangioma group (p < 0.05). The ADC value of hepatocellular carcinoma DWI sequence was (1.20 ± 0.17) ×10−3 mm2, which was significantly lower than that of hepatic hemangioma (p < 0.05). The area under ROC curve of BF, BV, HAP, and ADC values for hepatocellular carcinoma was 0.860, 0.754, 0.804, and 0.890, respectively. The area under ROC curve of the four groups was compared (p > 0.05). Conclusion CT perfusion parameters BF, BV, HAP, and DWI sequence ADC values have certain application value in the diagnosis of hepatocellular carcinoma, and there is no significant difference between the diagnostic value of each parameter.

Poster 133: Validation of 3D MRI in Glenohumeral Instability Evaluation of Glenoid and Humeral Bone Loss including Glenoid Track Compared to CT Scan

Objectives:The objective of our study is to determine whether the addition of 3-dimensional (3D) MRI to standard MRI sequences is comparable to 3D CT scan evaluation of glenoid and humeral bone loss in glenohumeral instability. There is increasing understanding of the importance of the glenoid, as well as humeral bone loss in outcomes and surgical decision making in patients with shoulder instability. Although magnetic resonance imaging (MRI) is performed as standard of care for soft tissue evaluation of shoulder instability, CT scan remains the gold standard in bony measurements. Standard MRI evaluation has been shown to inaccurately measure bone loss. However, additional CT scans result in increased financial, time, and ionizing radiation cost to the patient.Methods:Eighteen patients who presented with glenohumeral instability were prospectively enrolled and received both MRI and CT within 1 week of each other. The MRI included an additional sequence (VIBE) which underwent post-processing for reformations (Figure 1a). The addition of a VIBE protocol, on average is an addition 4 to 4.5minutes in the scanner. CT data also underwent 3D post-processing (Figure 1b) and therefore each patient had four imaging modalities (2D CT, 2D MRI, 3D CT reformats, and 3D MRI reformats). Each sequence underwent the following measurements from two separate reviewers: glenoid defect, glenoid defect percent, humeral defect, humeral defect percentage (Figure 2a and 2b), and evaluation of glenoid track and version. Paired t-tests were used to assess differences between imaging modalities and chi squared for glenoid track. Intra-observer and inter-observer reliability were evaluated. Bland-Altman tests were also performed to assess the agreement between CT and MRI. In addition, we determined cost of each imaging modality at our single institution.Results:3D MRI measurements for glenoid and humeral bone loss measurements were comparable to 3D CT (Table 1). There were no significant differences for glenoid defect size and percentage, or humeral defect size and percentage (P>0.05) (Table 2). Bland-Altman analysis demonstrated strong agreement with small measurement errors for 3D CT and 3D MRI percentage glenoid bone loss. There was also no difference in evaluation for determining on vs off track between any of the imaging modalities. Inter- and intra-rater reliability was good to excellent for all CT and MRI measurements (r >= 0.7).Conclusions:3D MRI measurements for bone loss in glenohumeral instability through utilization of VIBE sequence were equivalent to 3D CT. At our institution, the costs of MRI with 3D reconstruction was 1.67x cheaper than MRI and CT with 3D reconstructions. 3D MRI may be a useful adjuvant to standard MRI sequences to allow concurrent soft tissue and accurate assessment of glenoid and humeral bone loss in glenohumeral instability.Figure 1a.(3D MRI glenoid reformation) and lb (3D CT glenoid reformation): Glenoid measurement for 3D reconstruction of MRI and CT using sagittal en face of the glenoid. A circle was placed over the inferior portion of the glenoid using margins as a guide for the circle. The glenoid height line (blue) runs from the supraglenoid tubercle to the medial aspect of the inferior base. Glenoid bone loss size (orange) and circle diameter (green) was quantified with glenoid height line marking the center of the circle. Percent glenoid bone loss was determined as [(glenoid bone loss size/circle diameter)* 100]. Glenoid track was determined through equation [(0.83 * circle diameter) - glenoid bone loss size]Figure 2a.(2D CT) and 2b (3D CT): 2a: Measurement of Hill Sachs maximal defect on axial 2D CT recorded in mm. 2b: Measurement of humeral defect percentage from the 3D reformats using sagittal projection with best fit circle. A line (blue) was placed to determine maximal humeral head height (A) then perpendicular line (green) to measure residual humeral head (B) and therefore bone defect (A-B)(orange). Percent bone loss was determined through [(A-B)/A)*100]Table 1:Mean 2D and 3D CT and MRI measurementsTable 2:Paired t-test Glenoid and Humeral Bone Loss Measurements.