Rapid magnetic resonance imaging–guided reduction of craniovertebral junction deformities

2009 ◽  
Vol 10 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Tim E. Darsaut ◽  
Muthana M. Sartawi ◽  
Perry Dhaliwal ◽  
Richard J. Fox
Keyword(s):  
Mr Imaging ◽  
Soft Tissues ◽  
Craniovertebral Junction ◽  
Resonance Imaging ◽  
Mr Images ◽  
Rapid Reduction ◽  
Plain Radiographs ◽  
Sequential Addition ◽  
Spine Board

The authors demonstrate the utility of an MR imaging–compatible traction board for the rapid reduction of craniovertebral junction (CVJ) deformities. To choose the appropriate surgical management, patients with compressive CVJ deformities often undergo a trial of traction. Conventional traction trials require the treating surgeon to infer from plain radiographs the manner in which traction forces affect neural and ligamentous structures at the CVJ. To avoid overdistraction injury, low increments of weight are added in a gradual fashion, a process that typically requires 48–72 hours. The authors outline the use of an MR imaging–compatible traction board to determine reducibility safely and rapidly in 4 patients with compressive CVJ deformities. Four patients with advanced CVJ deformities underwent a trial of MR imaging–guided traction performed using an MR imaging–compatible spine board. Serial sagittal images were acquired at baseline and following each sequential addition of force. All patients tolerated traction without neurological worsening. The neural elements were seen to be adequately decompressed in all cases during a single MR imaging session. Patients subsequently underwent craniocervical stabilization and fusion. Postoperative imaging showed maintenance of the reduction without neural compression. An MR imaging–guided trial of traction can facilitate the rapid and safe determination of the reducibility of compressive lesions in patients with advanced CVJ deformities. Rapidly acquired sagittal MR images permit the surgeon to evaluate the effects of traction on the soft tissues at the CVJ, thereby expediting the traction trial and avoiding the risks of immobility in this often-fragile patient population.

scholarly journals Comparison of radiography and magnetic resonance imaging in the diagnosis of hand osteoarthritis

2019 ◽  
Vol 57 (1) ◽  
pp. 91-99 ◽  
Author(s):  
D. M. Kudinsky ◽  
A. V. Smirnov ◽  
L. I. Alekseeva
Keyword(s):  
Magnetic Resonance Imaging ◽  
Articular Cartilage ◽  
Magnetic Resonance ◽  
Bone Marrow Edema ◽  
Soft Tissues ◽  
Joint Space ◽  
Hand Osteoarthritis ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

The article discusses the possibilities and search for the optimal concept of diagnosis of hand osteoarthritis (OA). The data of numerous studies with focus on the comparison of sensitivity and specificity of the main techniques in this type of pathology – standard radiography and magnetic resonance imaging (MRI) are presented. Determination of the earliest symptoms of OA allows to predict the development of the disease and begin its therapy. The joint space narrowing due to the loss of articular cartilage is the earliest radiological symptom of OA, which is observed in the advanced stage of the disease. MRI, unlike radiography, makes it possible to visualize the articular cartilage, fluid in the joint cavity, bone marrow edema and soft tissues, but it is more expensive and time-consuming method. At present the main difficulty lies in the absence of a standardized system for assessing the MRI hand OA manifestations, as well as insufficient number of investigations in this area.

Radiographic and Magnetic Resonance Imaging of the Symptomatic Synthetic Cartilage Implant

2019 ◽  
Vol 41 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Tonya W. An ◽  
Spenser Cassinelli ◽  
Timothy P. Charlton ◽  
Glenn B. Pfeffer ◽  
David B. Thordarson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Diagnostic Imaging ◽  
Revision Surgery ◽  
Soft Tissues ◽  
Joint Space ◽  
Resonance Imaging ◽  
Satisfaction Rating ◽  
Plain Radiographs

Background: Synthetic Cartilage Implantation (SCI; Cartiva) is a treatment of hallux rigidus associated with mixed clinical outcomes in the United States. Patients with persistent pain typically undergo diagnostic imaging for evaluation. We aimed to characterize the radiologic findings of SCI and surrounding tissues. Methods: This is a retrospective review of patients treated using SCI who underwent magnetic resonance imaging (MRI) for persistent pain. Metatarsophalangeal (MTP) joint spaces were compared on plain radiographs of the foot immediately postoperatively and at most recent follow-up. MRI of the foot were assessed for dimensions of the implant, bony channel, and presence of peri-implant fluid. Clinical follow-up, including Patient-Reported Outcome Measures Informational System (PROMIS) scores, satisfaction rating, and revision surgery, was collected. Eighteen cases of symptomatic SCI from 16 patients (13 females, 3 males) were included. All but 1 case involved a 10-mm implant. Results: Mean satisfaction rating was 2.25 (1-5 Likert scale). PROMIS scores indicated moderate physical dysfunction (41) and moderate pain interference (63). Six of 16 patients (37.5%) underwent revision surgery at average 20.9 months of follow-up. Plain radiographs over a 13.3-month interval showed joint space narrowing of 2 mm medially and 1.6 mm laterally ( P < .001). One hundred percent of cases had radiographic evidence of osteoarthritis (OA) progression. MRI studies were obtained on average 11.5 months postoperatively. The implant diameter averaged 9.7 mm, which mismatched the bony channel diameter of 11.2 mm ( P < .001). Fourteen of 18 cases had peri-implant fluid. All cases had edema in the metatarsal, proximal phalanx, and soft tissues. Conclusion: Radiographic loss of MTP joint space and progression of arthritis were present for all cases studied. MRI revealed bony channel widening and a smaller implant, with peri-implant fluid suggesting instability at the implant-bone interface. Persistent edema was observed in soft tissues and bone. Diagnostic imaging of SCI in symptomatic patients demonstrated concerning findings that merit further correlation with patient outcomes. Level of Evidence: Level IV, case series.

Magnetic Resonance Imaging with Maximum Contrast between Two Selected Tissues Composed of Recordings with Three Repetition Times

1988 ◽  
Vol 29 (1) ◽  
pp. 140-142
Author(s):  
B. Jung ◽  
A. Ericsson ◽  
A. Hemmingsson ◽  
G. O. Sperber ◽  
K.-Å. Thuomas
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Liver Metastases ◽  
Normal Liver ◽  
Liver Parenchyma ◽  
Intensity Difference ◽  
Resonance Imaging ◽  
Mr Images ◽  
Imaging Parameters

A method is presented which in a composed image maximizes the image intensity difference between two selected tissues. The composition is made from several magnetic resonance (MR) images from the same slice but with different MR imaging parameters. The method is illustrated with a patient with liver metastases for whom the technique was used to emphasize metastases above normal liver parenchyma.

Syringomyelia-Chiari complex: magnetic resonance imaging and clinical evaluation of surgical treatment

1990 ◽  
Vol 73 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Jesús Vaquero ◽  
Roberto Martínez ◽  
Alicia Arias
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Posterior Fossa ◽  
Surgical Techniques ◽  
Posterior Fossa Decompression ◽  
Subjective Improvement ◽  
Resonance Imaging ◽  
Mr Images ◽  
Content Type ◽  
Spinal Cord Damage

✓ Thirty patients with syringomyelia-Chiari complex who underwent posterior fossa decompression or syringosubarachnoid shunting were studied clinically and by magnetic resonance (MR) imaging to assess the changes in the syrinx and in their clinical picture after surgery. When symptoms of posterior fossa compression were present, posterior fossa decompression was performed; however, when symptoms of posterior fossa compression were absent, the choice of posterior fossa decompression or syringosubarachnoid shunting depended, respectively, on whether the syrinx was narrow or wide on MR imaging. At least 1 year after surgery, subjective improvement or arrest of disease was recorded in 73% of the patients. The present study suggests that: 1) the symptoms attributed to spinal cord damage have no significant relationship to the size of the syrinx on MR images; 2) the surgical techniques employed in this series (posterior fossa decompression or syringosubarachnoid shunt) were equally useful in inducing syrinx collapse; and 3) when posterior fossa decompression is performed, plugging of the obex is not necessary for syrinx collapse.

Magnetic resonance imaging: an accurate method to evaluate arteriovenous malformations after stereotactic radiosurgery

1996 ◽  
Vol 85 (6) ◽  
pp. 1044-1049 ◽  
Author(s):  
Bruce E. Pollock ◽  
Douglas Kondziolka ◽  
John C. Flickinger ◽  
Atul K. Patel ◽  
David J. Bissonette ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Cerebral Angiography ◽  
False Negative ◽  
Resonance Imaging ◽  
Mr Images ◽  
Content Type ◽  
Fine Print

✓ To determine the accuracy of magnetic resonance (MR) imaging in comparison to cerebral angiography after radiosurgery for an arteriovenous malformation (AVM), the authors reviewed the records of patients who underwent radiosurgery at the University of Pittsburgh Medical Center before 1992. All patients in the analysis had AVMs in which the flow-void signal was visible on preradiosurgical MR imaging. One hundred sixty-four postradiosurgical angiograms were obtained in 140 patients at a median of 2 months after postradiosurgical MR imaging (median 24 months after radiosurgery). Magnetic resonance imaging correctly predicted patency in 64 of 80 patients in whom patent AVMs were seen on follow-up angiography (sensitivity 80%) and angiographic obliteration in 84 of 84 patients (specificity 100%). Overall, 84 of 100 AVMs in which evidence of obliteration was seen on MR images displayed angiographic obliteration (negative predictive value, 84%). Ten of the 16 patients with false-negative MR images underwent follow-up angiography: in seven the lesions progressed to complete angiographic obliteration without further treatment. Exclusion of these seven patients from the false-negative MR imaging group increases the predictive value of a negative postradiosurgical MR image from 84% to 91%. No AVM hemorrhage was observed in clinical follow up of 135 patients after evidence of obliteration on MR imaging (median follow-up interval 35 months; range 2–96 months; total follow up 382 patient-years). Magnetic resonance imaging proved to be an accurate, noninvasive method for evaluating the patency of AVMs that were identifiable on MR imaging after stereotactic radiosurgery. This imaging modality is less expensive, more acceptable to patients, and does not have the potential for neurological complications that may be associated with cerebral angiography. The risk associated with follow-up cerebral angiography may no longer justify its role in the assessment of radiosurgical results in the treatment of AVMs.

Magnetic resonance imaging for detection of late meniscal tears in dogs following tibial tuberosity advancement for treatment of cranial cruciate ligament injury

2014 ◽  
Vol 27 (02) ◽  
pp. 141-146 ◽  
Author(s):  
C. R. Lamb ◽  
M. S. Tivers ◽  
A. Li ◽  
F. Taylor-Brown
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Cruciate Ligament ◽  
Meniscal Tear ◽  
Ligament Injury ◽  
Meniscal Tears ◽  
Resonance Imaging ◽  
Mr Images ◽  
Cranial Cruciate Ligament

SummaryTo document the use of and to estimate the accuracy of magnetic resonance (MR) imaging for detection of late meniscal tears in dogs with cranial cruciate ligament injury treated with tibial tuberosity advancement (TTA).Medical records of dogs that had TTA followed by stifle MR imaging for suspected meniscal tear and subsequent arthrotomy were reviewed retrospectively. Magnetic resonance images were reviewed independently by an observer blinded to clinical information who classified menisci as torn, abnormal but intact, or normal. Magnetic resonance and surgical findings were compared.Eight stifles from large breed dogs were included. Six stifles had a medial meniscal tear identified in MR images and later confirmed surgically. In the remaining two stifles, the menisci appeared intact in MR images and no tear was identified at subsequent arthrotomy. Lateral menisci in all stifles appeared intact in MR images and were considered normal at surgery. Susceptibility artefacts associated with TTA implants were present in all images but did not adversely affect interpretation of intra-articular structures.Magnetic resonance imaging appears to be accurate for diagnosis of late meniscal tears. Artefacts associated with TTA implants did not prevent evaluation of critical intra-articular structures. Further investigation with MR imaging should be considered when late meniscal tear is suspected following TTA.

scholarly journals Gd3+-DTPA-Meglumine-Anionic Linear Globular Dendrimer G1: Novel Nanosized Low Toxic Tumor Molecular MR Imaging Agent

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Tahmineh Darvish Mohamadi ◽  
Massoud Amanlou ◽  
Negar Ghalandarlaki ◽  
Bita Mehravi ◽  
Mehdi Shafiee Ardestani ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Citric Acid ◽  
Magnetic Resonance ◽  
Early Diagnosis ◽  
Mr Imaging ◽  
Contrast Media ◽  
Cancer Treatment ◽  
Diagnostic Methods ◽  
Resonance Imaging ◽  
Mr Images

Despite the great efforts in the areas of early diagnosis and treatment of cancer, this disease continues to grow and is still a global killer. Cancer treatment efficiency is relatively high in the early stages of the disease. Therefore, early diagnosis is a key factor in cancer treatment. Among the various diagnostic methods, molecular imaging is one of the fastest and safest ones. Because of its unique characteristics, magnetic resonance imaging has a special position in most researches. To increase the contrast of MR images, many pharmaceuticals have been known and used so far. Gadopentetate (with commercial name Magnevist) is the first magnetic resonance imaging contrast media that has been approved by the US Food and Drug Administration. In this study, gadopentetate was first synthesized and then attached to a tree-like polymer called dendrimer which is formed by polyethylene glycol core and surrounding citric acid groups. Stability studies of the drug were carried out to ensure proper synthesis. Then, the uptake of the drug into liver hepatocellular cell line and the drug cytotoxicity were evaluated. Finally, in vitro and in vivo MR imaging were performed with the new synthetic drug. Based on the findings of this research, connecting gadopentetate to dendrimer surface produces a stronger, safer, and more efficient contrast media. Gd(III)-diethylenetriamine pentaacetate-meglumine-dendrimer drug has the ability to enter cells and does not produce significant cytotoxicity. It also increases the relaxivity of tissue and enhances the MR images contrast. The obtained results confirm the hypothesis that the binding of gadopentetate to citric acid dendrimer produces a new, biodegradable, stable, and strong version of the old contrast media.

scholarly journals Artifacts reduction in strain maps of tagged magnetic resonance imaging using harmonic phase

Open Medicine ◽  
2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Daolei Wang ◽  
YaBo Fu ◽  
Muhammad Aqeel Ashraf
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Soft Tissues ◽  
Myocardial Strain ◽  
Resonance Imaging ◽  
Mr Images ◽  
Harmonic Phase ◽  
Tagged Mr Images ◽  
Dc Component ◽  
Tagged Magnetic Resonance Imaging

AbstractTagged Magnetic Resonance Imaging (MRI) is a noninvasive technique for examining myocardial function and deformation. Tagged MRI can also be used in quasistatic MR elastography to acquire strain maps of other biological soft tissues. Harmonic phase (HARP) provides automatic and rapid analysis of tagged MR images for the quantification and visualization of myocardial strain. We propose a new artifact reduction method in strain maps. Image intensity of the DC component is estimated and subtracted from spatial modulation of magnetization (SPAMM) tagged MR images. DC peak interference in harmonic phase extraction is greatly reduced after DC component subtraction. The proposed method is validated using both simulated and MR acquired tagged images. Strain maps are obtained with better accuracy and smoothness after DC component subtraction.

A distinct phenotypic change in gliomas at the time of magnetic resonance imaging detection

2008 ◽  
Vol 108 (4) ◽  
pp. 782-790 ◽  
Author(s):  
Taichang Jang ◽  
Binulal Sathy ◽  
Yi-Hua Hsu ◽  
Milton Merchant ◽  
Benjamin Recht ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Phenotypic Change ◽  
In Utero Exposure ◽  
Resonance Imaging ◽  
Mr Images ◽  
Cancer Aggressiveness ◽  
Imaging Detection ◽  
And Diffusion ◽  
Sequential Appearance

Object Although gliomas remain refractory to treatment, it is not clear whether this characteristic is fixed at the time of its origin or develops later. The authors have been using a model of neurocarcinogenesis to determine whether a time exists during a glioma's evolution during which it is detectable but still curable, thus providing a justification for exploring the clinical merits of an early detection and treatment strategy. The authors recently reported the presence of 2 distinct cellular subsets, 1 expressing nestin and the other both glial fibrillary acidic protein (GFAP) and osteopontin (OPN), within all examined gliomas that developed after in utero exposure to ethylnitrosourea. Methods In this study, the authors used magnetic resonance (MR) imaging to assess when these 2 subpopulations appeared during glioma evolution. Results Using T2-weighted and diffusion-weighted MR imaging, the authors observed that gliomas grew exponentially once detected at rates that were location-dependent. Despite large differences in growth rates, however, they determined by correlating histochemistry with imaging in a second series of animals, that all lesions initially detected on T2-weighted images contained both subsets of cells. In contrast, lesions containing only nestin-positive cells, which appeared on average 40 days before detection on MR images, were not detected. Conclusions The sequential appearance of first the nestin-positive cells followed several weeks later by those expressing GFAP/OPN suggests that all gliomas arise through common early steps in this model. Furthermore, the authors hypothesize that the expression of OPN, a molecule associated with cancer aggressiveness, at the time of T2-weighted detection signals a time during glioma development when the lesion becomes refractory to treatment.

The predictive value of low–field strength magnetic resonance imaging for intraoperative residual tumor detection

2009 ◽  
Vol 111 (2) ◽  
pp. 252-257 ◽  
Author(s):  
Robert A. Hirschl ◽  
Jeff Wilson ◽  
Brandon Miller ◽  
Sergio Bergese ◽  
E. Antonio Chiocca
Keyword(s):  
Mr Imaging ◽  
Field Strength ◽  
Imaging System ◽  
Tumor Resection ◽  
High Strength ◽  
Residual Tumor ◽  
Intracranial Tumor ◽  
Resonance Imaging ◽  
Mr Images ◽  
Low Field

Object Neurosurgeons have been utilizing intraoperative MR (iMR) imaging to evaluate the extent of tumor resection since the 1990s. A low–field strength (0.12 T) MR imaging unit (PoleStar N20, Medtronic) is a practical and relatively inexpensive iMR imaging system that has found increased use in neurosurgery. The gold standard for postoperative detection of residual tumor has been high-strength MR imaging performed within 48 hours of resection. The object of this study was to determine the predictive concordance of low-strength iMR imaging with standard high-strength MR imaging for detection of residual tumor. Methods The authors retrospectively evaluated the MR images from 74 intracranial tumor resections, comparing the intraoperative images obtained using a 0.12-T iMR imaging unit to the immediate postoperative images obtained using a standard 1.5-T MR imaging unit within 48 hours after surgery. Results The sensitivity of low-field MR imaging for detection of residual tumor was 0.74 (95% CI 0.58–0.86), and its specificity was 0.97 (95% CI 0.83–1). When only glial tumors (42 of the 74 lesions) were analyzed, the sensitivity was 0.82 (95% CI 0.59–0.94) and the specificity was 0.95 (95% CI 0.73–1). Conclusions These data could assist the neurosurgeon who has to decide intraoperatively whether the observed iMR images show residual tumor or not.

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