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PubMed2006

Characterization of the peri-infarction zone using T2-weighted MRI and delayed-enhancement MRI in patients with acute myocardial infarction.

To characterize the peri-infarction zone using T2-weighted (T2w) magnetic resonance imaging (MRI) and infarct size on delayed enhancement (DE) MRI in patients with acute myocardial infarction (AMI). In 65 patients, short-axis T2w and DE MRI images were acquired 5 +/- 3 d after AMI. The MRI was analyzed using a threshold method defining infarct size on DE MRI and edema on T2w MRI as areas with signal intensity larger than +2 SD above remote normal myocardium. The peri-infarction zone was calculated as the difference between the size of edema and the infarct size. The size of edema on T2w MRI (31.3 +/- 13.4% of LV area) was larger than the infarct size on DE MRI (20.3 +/- 10.4% of LV area, p< 0.0001). The size of the peri-infarction zone was 11.0 +/- 10.0% of the LV area. Good correlation was found between infarct size on DE MRI and peak creatine kinase (CK) isoenzyme MB (r = 0.65, p< 0.0001), but there was no correlation between the size of the peri-infarction zone and CK MB (r = 0.05, p = 0.67). The peri-infarction zone was larger in patients with an infarct size <28% of the LV area (12.6 +/- 10.0% LV area) compared with patients with an infarct size > or =28% of the LV area (6.7 +/- 9.0% of the LV area, p< 0.05). The peri-infarction zone does not correlate with enzymatic parameters of infarct size and is substantially larger in small infarcts, indicating viable myocardium.

Adult↗

PubMed2000

Linomide in relapsing and secondary progressive MS: part II: MRI results. MRI Analysis Center of the University of Texas-Houston, Health Science Center, and the North American Linomide Investigators.

OBJECTIVE: To determine the safety and efficacy of roquinimex (linomide) in the management of relapsing-remitting and secondary progressive MS as monitored by MRI. BACKGROUND: Preclinical studies and several short term randomized trials of linomide suggested clinical and MRI-measured benefits with acceptable risk for closely followed MS patients. METHODS: The North American Linomide Trial formally screened 853 individuals for relapsing or secondary progressive, clinically definite MS; recent disease activity or progression; and an Expanded Disability Status Scale score at entry of 3.0 to 6.5 inclusive. MRI was obtained on 811 subjects at pre-enrollment, 718 cases at enrollment, and then at three monthly intervals until the trial was prematurely terminated for unacceptable toxicity. RESULTS: Enhancement was found on 40.2% of 718 entry scans. Statistically robust correlations were found between clinical demographic data and several entry MRI measures including CSF volume, a reflection of brain atrophy. Assessment of the effect of treatment on MRI-measured disease was limited by early trial termination. However, active treatment for 3 months reduced the proportion of patients with one or more enhancements. An exploratory analysis suggested that 2.5 mg was the most active of three doses tested in limiting the total volume of enhanced tissue, the proportion of MRI-defined lesions designated as "black holes," and by a novel MRI composite disease measure. CONCLUSIONS: The short term signature of the effect of linomide on MRI-measured aspects of the disease suggests that safer drugs of this class might be useful in the management of MS. The use of a composite index of the heterogeneous nature of the pathology of MS as captured by MRI may have merit as an outcome measure in clinical trials.

Adjuvants, Immunologic↗

PubMedDate not supplied

MRI in the acute phase of spinal cord traumatic lesions: Relationship between MRI findings and neurological outcome.

PURPOSE: To evaluate the role of emergency MRI in the diagnosis of acute spinal injuries, and to correlate the MRI pattern with the neurological outcome. MATERIALS AND METHODS: Thirty-eight patients with MRI-proven spinal cord injury were classified according to the Frankel classification. MRI was always performed within 8 hours from trauma. Frankel classification divides spinal cord injuries into 5 classes of decreasing severity based on the presence of motor and/or sensory function loss. On the basis of the MRI findings the patients were classified in 3 groups: group 1 (intramedullary haematoma), group 2 (multi-metamer oedema), group 3 (single-metamer oedema). All patients underwent neurosurgery and were clinically evaluated until the stabilization of neurological recovery. Mean follow-up time was 12 months. The MR images were retrospectively evaluated and correlated to the neurological outcome. RESULTS: Twenty-eight patients showed complete motor loss (Frankel classes A and B); of these 28 patients 12 (42.8%) had MRI evidence of intramedullary haematoma, 12 (42.8%) had multi-metamer oedema and 4 (14.4%) had single-metamer oedema. Of the 10 patients with incomplete motor loss, none had MRI evidence of haemorrhage, 4 (40%) showed multi-metamer oedema and 6 (60%) showed single-metamer oedema. Follow-up clinical assessment revealed that 14/38 patients (36,8%) had clinical improvement and 2/38 cases (5%) had a complete motor recovery, as demonstrated by the move to a higher Frankel class. CONCLUSIONS: Our results, consistent with previous reports, confirm a strong correlation between the MRI appearance of traumatic spinal cord injuries in acute phase and long-term recovery of motor and sensory function: patients with initial haemorrhage had a poor prognosis, whereas those with spinal cord oedema had a good clinical outcome, as demonstrated by the passage to a higher Frankel class. MRI is particularly important in the initial evaluation of unconscious patients who cannot undergo a motor and sensory neurological evaluation, and to define the prognosis, which will influence the correct therapeutic choice.

Acute Disease↗

PubMed1996

Magnetic resonance imaging (MRI) for detection of active sacroiliitis--a prospective study comparing conventional radiography, scintigraphy, and contrast enhanced MRI.

OBJECTIVE: Sacroiliitis is often difficult to diagnose in the absence of radiographic alterations. For the diagnosis of active sacroiliitis, plain radiography, scintigraphy, and contrast enhanced magnetic resonance imaging (MRI) were evaluated in a prospective study. METHODS: In 44 consecutive patients with complete clinical and laboratory evaluation, plain radiographs, quantitative sacroiliac (SI) scintigraphy, and MRI were performed to evaluate the contribution of these imaging techniques to the diagnosis of active sacroiliitis. Scintiscanning and MRI were done in 20 control subjects to define the normal range of imaging findings. We determined the sensitivity and specificity for each imaging method using a reference standard based on clinical symptoms of inflammatory low back pain with or without laboratory signs, and on clinical and radiographic followup during 1.5-2.5 years to confirm diagnosis. RESULTS: MRI was most sensitive (95%) and superior to quantitative SI scintigraphy (48%) or conventional radiography (19%) for the detection and confirmation of active sacroiliitis. For the assessment of inflammatory signs, MRI had higher specificity (100%) than scintigraphy (97%) or plain radiography (47%). At repeat MRI after 2-30 months, there was persistent pathologic signal intensity in the subchondral bone area despite clinically successful antiinflammatory drug therapy. CONCLUSION: For the assessment of active changes in the synovial portion and the subchondral bone marrow, contrast enhanced MRI is superior to quantitative SI scintigraphy or conventional radiography. MRI picks up an additional 75% of early cases not diagnosed by plain radiography. Scintigraphy is only of limited value. Persistent pathologic signal intensity in the subchondral bone marrow seems to be closely associated with previous inflammatory episodes, thus limiting specificity of MRI for active sacroiliitis. Based on our findings we suggest an algorithm for the evaluation of patients with suspected active sacroiliitis.

Adolescent↗

PubMed2006

Reliability and construct validity of the compatible MRI scoring system for evaluation of haemophilic knees and ankles of haemophilic children. Expert MRI working group of the international prophylaxis study group.

We tested the reliability and construct validity of the Compatible magnetic resonance imaging (MRI) scale for the evaluation of haemophilic knees and ankles and compared the diagnostic performance of MRI and plain film radiographs. Sagittal and coronal gradient-echo 1.5-T MR images of knees (n=22) and ankles (n=23) were obtained from boys (age range 4-16 years; mean 11 years) in two centres (Toronto, n=26; Europe, n=19). The MR images were independently read by four blinded radiologists on two occasions. Number of previous joint bleedings and laboratory level of severity of haemophilia were the reference standards for imaging assessment. Both components of the MRI scale demonstrated high inter- and intrareader intraclass correlation coefficients (progressive (P) scale, 0.91 and 0.94; additive (A) scale, 0.81 and 0.92 respectively). The correlation between the osteochondral domain of the MRI scale and patient's age was moderate. Otherwise, correlations between A- and P-scales and clinical laboratory measurements were weak. The areas under the curve (AUCs) used for discrimination of disease severity were similar for the A- and P-scales (AUCs used for mild disease, A-scale, 0.72+/-0.07; P-scale, 0.69+/-0.08; P=0.23; AUCs for severe disease, A-scale, 0.93+/-0.05; P-scale, 0.87+/-0.08; P=0.05). No differences were noted between the AUCs of the MRI and radiographic scales used for discrimination of late osteoarticular changes; MRI scales performed better for discrimination of early changes. In conclusion, both MRI scales demonstrated excellent reliability, poor convergent validity, and moderate and excellent validity for discrimination of mild and severe diseases respectively. Compared with radiographic scores, the MRI scales performed better for discrimination of early osteoarticular changes.

Adolescent↗

PubMed1995

On the relationship between feature-recognizing MRI and MRI encoded by singular value decomposition.

This paper describes the similarity between two methods of non-Fourier MRI: feature-recognizing MRI (FR MRI) and MRI with encoding by singular value decomposition (SVD MRI). Both methods represented images as truncated expansions of non-Fourier basis functions; these basis images were derived from prior image data by using closely-related mathematical techniques: the Karhunen-Loeve decomposition (or principal components analysis) and singular value decomposition, respectively. We demonstrate that FR and SVD MRI are equivalent in the following sense: given the same prior image data, they lead to exactly the same basis functions. FR MRI utilized prior images of the same body part in many "training" subjects, thought to be similar to the "unknown" subject to be imaged. SVD MRI utilized a single prior image of one subject in order to perform dynamic imaging of that subject. We demonstrate that the basis function expansion derived from a single prior image may not be capable of representing new features (features not found in the prior image). Therefore, the SVD basis functions may be inappropriate for dynamic imaging.

Artifacts↗

PubMed2004

[Comparison of high resolution whole-body MRI using parallel imaging and PET-CT. First experiences with a 32-channel MRI system].

PURPOSE: To compare the accuracy in the detection and staging of various malignant tumors with high resolution whole-body MRI using parallel imaging with whole-body dual-modality PET-CT. PATIENTS AND METHODS: Preliminary results of an interim analysis from a prospective, blinded study are presented, in which 20 patients (mean age 59 years, range 27-77 years) with different oncological diseases underwent whole-body dual modality FDG-PET-CT screening for tumor search or staging in case of confirmed or suspected metastatic disease. All patients also underwent whole-body MRI imaging with the use of parallel imaging (iPAT). High-resolution coronal T1w- and STIR-sequences of 5 body levels with 512 x 512 matrix, axial fast T2w imaging of lung and abdomen (HASTE), contrast-enhanced dynamic and static T1w-sequences of liver, brain, abdomen, and pelvis were performed. Using a 32-channel whole-body MRI scanner (Magnetom Avanto, Siemens Medical Solutions) with a total field of view of 205 cm and free table movement, all patients could be covered from head to toe within one examination. With this technique, high spatial resolution and acceptable scanning times could be obtained. Two experienced radiologists read the MRI-scans, one radiologist and one nuclear scientist read PET-CT scans, each in consensus in a clinical setting. Delineation of the primary tumor (T-stage) or recurrent tumor, pathologic lymph node involvement, as well as degree and localization of metastatic disease, was assessed using PET-CT as standard of reference. RESULTS: Metastases from gastrointestinal tumor (25%) and breast cancer (25%), genitourinary tumor (15%) and malignant melanoma (15%) were detected. In 4/20 patients the primary tumor was identified, 2/20 patients showed recurrent tumor. Of 140 malignant lesions detected by PET-CT, 124 lesions were detected with MRI, resulting in a sensitivity of 89% at a specificity of 86%. In malignant lymph node detection, sensitivity of MRI was 83% and specificity 85%. CONCLUSION: Whole-body MRI is a promising technique in the detection of primary tumor and metastatic disease. Sensitivity in the assessment of lymph node metastases seems to be limited. With the use of parallel imaging (iPAT), dedicated high-resolution whole-body MRI is possible within acceptable scanning times.

Adult↗

PubMed2005

MRI of the breast: comparison of MRI signals and histological characteristics of the same slices.

The development of MRI with high spatial resolution and a special breast coil has contributed to more-accurate diagnosis of breast tumor, such as determination of morphologic characteristics including internal architecture of the breast lesion. To clarify how individual MRI findings reflect the pathological findings, we made slices of resected breast lesions identical to those obtained with axial MRI and compared them respectively according to histological subtype of tumors. In this article, we present MRI findings on the basis of histopathological evidence. In general, fibroadenomas (FA) show a well-defined border on contrast-enhanced fat-suppressed T1-weighted images (CFT1). However, a subtype of fibroadenoma, mastopathic type, with a poorly defined border on CFT1 and carcinoma-like enhancement, is similar to cancer on MRI. Scirrhous carcinomas take either of two patterns on dynamic MRI, i.e., homogeneous enhancement or thick irregular peripheral ring enhancement. The latter type shows central fibrosis zones histologically. Papillotubular carcinoma shows a spotted pattern on dynamic MRI. The low-enhancement areas within the spotted pattern reflect parenchyma between clusters of cancer. Solid-tubular carcinoma shows thin peripheral enhancement on dynamic MRI and linear high signal on CFT1. This finding of CFT1 corresponds to infiltration of lymph cells and fibroblast cells in the adjacent zone. Invasive lobular carcinoma shows nonmass lesions and a slow gradual enhancement pattern. Mucinous carcinomas show high signal intensity on T2-weighted images because of mucin and reveal gradual enhancement. The ill-defined border of mucinous carcinoma on CFT1 is useful to distinguish it from FA.

Breast↗

PubMed2000

[Left ventricular heart volume determination with fast MRI in breath holding technique: how different are quantitative heart catheter, quantitative MRI and visual echocardiography?].

GOAL: Comparison of fast MRI, echocardiography (Echo), and ventricular angiography (Cath) in the assessment of left ventricular global function. METHODS: Fast MRI in short axis plane, biplane Cath, and 2D Echo were performed in 62 patients [35 coronary artery diseases, 16 acquired valvular diseases (VD), 9 dilated cardiomyopathies (DCM), 1 congenital heart disease and 1 heart transplantation]. Enddiastolic (EDV), endsystolic (ESV), stroke volumes (SV), cardiac output (CO), and ejection fraction (EF) were compared in MRI and Cath. EF was visually estimated in 2D Echo by an experienced observer. RESULTS: In comparison to MRI, Cath overestimated EF by 8.4%, and Echo underestimated EF by 5.6%. The limits of agreement between MRI and Cath in EF were +/- 23.8%, between MRI and Echo +/- 18%, and between Echo and Cath +/- 19.4%. Significant differences were found between Cath and MRI in EDV, SV, and CO, but not for ESV. The best agreement in EF was found in the group with DCM, the worst in the group with VD. CONCLUSION: Important systemic and random errors were found in the comparison of MRI, Echo, and Cath. For therapy decision and follow-up, the methods should not be exchanged unscrupulously.

Adult↗

PubMed2003

Toward an MRI-based method to measure non-uniform cartilage deformation: an MRI-cyclic loading apparatus system and steady-state cyclic displacement of articular cartilage under compressive loading.

Recent magnetic resonance imaging (MRI) techniques have shown potential for measuring non-uniform deformations throughout the volume (i.e. three-dimensional (3D) deformations) in small orthopedic tissues such as articular cartilage. However, to analyze cartilage deformation using MRI techniques, a system is required which can construct images from multiple acquisitions of MRI signals from the cartilage in both the underformed and deformed states. The objectives of the work reported in this article were to 1) design an apparatus that could apply highly repeatable cyclic compressive loads of 400 N and operate in the bore of an MRI scanner, 2) demonstrate that the apparatus and MRI scanner can be successfully integrated to observe 3D deformations in a phantom material, 3) use the apparatus to determine the load cycle necessary to achieve a steady-state deformation response in normal bovine articular cartilage samples using a flat-surfaced and nonporous indentor in unconfined compression. Composed of electronic and pneumatic components, the apparatus regulated pressure to a double-acting pneumatic cylinder so that (1) load-controlled compression cycles were applied to cartilage samples immersed in a saline bath, (2) loading and recovery periods within a cycle varied in time duration, and (3) load magnitude varied so that the stress applied to cartilage samples was within typical physiological ranges. In addition the apparatus allowed gating for MR image acquisition, and operation within the bore of an MRI scanner without creating image artifacts. The apparatus demonstrated high repeatability in load application with a standard deviation of 1.8% of the mean 400 N load applied. When the apparatus was integrated with an MRI scanner programmed with appropriate pulse sequences, images of a phantom material in both the underformed and deformed states were constructed by assembling data acquired through multiple signal acquisitions. Additionally, the number of cycles to reach a steady-state response in normal bovine articular cartilage was 49 for a total cycle duration of 5 seconds, but decreased to 33 and 27 for increasing total cycle durations of 10 and 15 seconds, respectively. Once the steady-state response was achieved, 95% of all displacements were within +/- 7.42 microns of the mean displacement, indicating that the displacement response to the cyclic loads was highly repeatable. With this performance, the MRI-loading apparatus system meets the requirements to create images of articular cartilage from which 3D deformation can be determined.

Adaptation, Physiological↗

PubMed2001

United States open-label glatiramer acetate extension trial for relapsing multiple sclerosis: MRI and clinical correlates. Multiple Sclerosis Study Group and the MRI Analysis Center.

After the placebo-controlled extension of the pivotal US trial of glatiramer acetate for the treatment of relapsing multiple sclerosis ended, 208 participants entered an open-label, long-term treatment protocol Magnetic resonance imaging (MRI) was added to the planned evaluations of these subjects to determine the consequences of long-term treatment on MRI-defined pathology and evaluate its clinical correlates. Of the 147 subjects that remained on long-term follow-up, adequate images were obtained on 135 for quantitative MRI analysis. The initial imaging sessions were performed between June 1998 and January 1999 at 2,447 +/- 61 days (mean +/- standard deviation) after the subject's original randomization. Clinical data from a preplanned clinical visit were matched to MRI within 3 +/- 51 days. At imaging, 66 patients originally randomized to placebo (oPBO) in the pivotal trial had received glatiramer acetate for 1,476 +/- 63 days, and 69 randomized to active treatment with glatiramer acetate (oGA) were on drug for 2,433 +/- 59 days. The number of documented relapses in the 2 years prior to entering the open-label extension was higher in the group originally randomized to placebo (oPBO=1.86 +/- 1.78, oGA=1.03 +/- 1.28; P=0.002). The annualized relapse rate observed during the open-label study was similar for both groups (oPBO=0.2 7, +/- 0.45 oGA=0.28 +/- 0.40), but the reduction in rate from the placebo-controlled phase was greater for those beginning therapy with GA (oPBO reduced by 0.66 +/- 0.71, oGA reduced by 0.23 +/- 0.58; P=0.0002). One or more gadolinium enhancing lesions were found in 27.4% of all patients (number of distinct enhancements=1.16 +/- 2.52, total enhanced tissue volume=97 +/- 26 microl). The risk of having an enhancement was higher in those with relapses during the open-label extension (odds ratio 4.65, 95% confidence interval (CI) 2.0 to 10.7; P=0.001). The odds for finding an enhancement was 2.5 times higher for those patients originally randomized to placebo (CI 1.1 to 5.4; P=0.02) compared to those always on glatiramer acetate. MRI-metrics indicative of chronic pathology, particularly measures of global cerebral tissue loss (atrophy), were uniformly worse for those originally on placebo. These observations enrich our long-term follow up of the clinical consequences of treatment with glatiramer acetate to include its apparent effects on MRI-defined pathology. They show that the effect of glatiramer acetate on enhancements is definite, but modest, consistent with the drug's described mechanisms of action, and that a delay in initiating treatment results in progression of MRI-measured pathology that can be prevented.

Adult↗

PubMed2003

[MRI in Crohn's disease after transduodenal contrast administration using negative oral MRI contrast media].

PURPOSE: To compare the efficacy and quality of conventional and MR enteroclysis with different filling methods regarding the assessment of extension and extraluminal manifestations in Crohn's disease. MATERIAL AND METHODS: 190 patients with known Crohn's disease were studied following small bowel enteroclysis, after oral administration or direct transduodenal filling in the MRI-department.T1- and T2-weighted breathhold MRI-scans w/o spectral fat suppression w/o i.v. Gd-DTPA were applied using negative oral superparamagnetic contrast media. RESULTS: Typical findings were marked bowel wall thickening with laminated wall contrast enhancement. In 135 patients 98,2% of affected bowel segments, 97,5% of stenoses and all 16 fistulas were detected, when conventional enteroclysis was employed as standard of reference. Additional important extraluminal findings such as ileoileal (n = 18), ileosigmoidal adhesions (n = 12), extraluminal abscesses (n = 35) and pseudotumors (n = 8) were visualized in 73/135 patients. Concerning the distension of jejunum and ileum, oral filling was rated significantly inferior to transduodenal filling in all small bowel segments,whereas filling in the MRI-unit was rated superior to fluoroscopic, mostly due to a mean transport time of 20 min to the MRI-unit. CONCLUSION: No clinically important findings of enteroclysis were missed when using MRI. Therefore, in patients with Crohn's disease, conventional enteroclysis can be replaced by MRI. For optimal bowel distension oral contrast administration is inferior to transduodenal filling, if a larger time delay between filling and the MRI-scan can be avoided.

Administration, Oral↗

PubMed1997

MRI of neuronal ceroid lipofuscinosis. II. Postmortem MRI and histopathological study of the brain in 16 cases of neuronal ceroid lipofuscinosis of juvenile or late infantile type.

Postmortem MRI was carried out on the formalin-fixed brains of 14 patients with juvenile (JNCL) and two with late infantile neuronal ceroid lipofuscinosis, one of variant and the other of classical type. Two patients with JNCL had also undergone MRI during life. After MRI, specimens for histopathological analysis were taken from standard areas of the cerebral cortex, deep nuclei and white matter. The signal intensity of the periventricular white matter was usually higher than that of the peripheral white matter, a finding which correlated with the severe periventricular loss of myelin and gliosis observed histologically. The signal intensity was usually lower in the thalamus than in the putamen; in some patients the signal intensity of the thalamus was equal to or even lower than that of the white matter. However, myelin loss, gliosis, the storage process or neuronal loss in the thalamus did not correlate with the MRI findings. Since in one patient with JNCL the ante- and postmortem MRI did not differ basically, it appears probable that the periventricular changes detected in vivo on MRI are due to the severe loss of myelin and gliosis observed in this study. However, changes resulting from the fixation process must be considered, when postmortem and in vivo MRI are correlated.

Adolescent↗

PubMed2000

Serial anatomy of the larynx in MRI: MRI-histologic correlations.

The larynx is an organ with a complex anatomic structure. MRI allows the performance of sections in the three planes of space, so that this study of the soft parts of the larynx yields results superior to those of other imaging techniques. Together with laryngoscopy, MRI is most often used in assessing the extension of malignant laryngeal tumors. This assessment is fundamental in choosing the indications for surgery, but the published reports of MRI of the larynx are sometimes discordant. The visualization of certain important anatomic structures such as the conus elasticus is uncertain. Our aim was to study the MRI radio-anatomy of the larynx based on correlations between MRI and histologic sections. Eight anatomic specimens were studied: four in the transverse plane, two in the sagittal plane, and two in the frontal plane. The MRI and histologic sections made at the same levels were compared. These comparisons allowed a description of the sectional radio-anatomy of the larynx and an assessment of the reliability and limitations of MRI. All the major anatomic structures could be identified. It was possible to demonstrate the conus elasticus. We were able to visualize the vocal process of the arytenoid cartilage, which has not to our knowledge been previously described in the literature.

Aged↗

PubMed2002

MRI-guided periradicular nerve root infiltration therapy in low-field (0.23-T) MRI system using optical instrument tracking.

The purpose of this study was to evaluate the feasibility of the MRI-guided periradicular nerve root infiltration therapy. Sixty-seven nerve root infiltrations under MRI guidance were done for 61 patients suffering from lumbosacral radicular pain. Informed consent was acquired from all patients. A 0.23-T open-MRI scanner with interventional tools (Outlook Proview, Philips Medical Systems, MR Technologies, Finland) was used. A surface coil was used in all cases. Nerve root infiltration was performed with MRI-compatible 20-G needle (Chiba type MReye, Cook, Bloomington, Ind.; or Manan type, MD Tech, Florida). The evaluation of clinical outcome was achieved with 6 months of clinical follow-up and questionnaire. The effect of nerve root infiltration to the radicular pain was graded: 1=good to excellent, i.e., no pain or not disturbing pain allowing normal physical activity at 3 months from the procedure; 2=temporary, i.e., temporary relief of pain; 3=no relief of pain; and 4=worsening of pain. As an adjunct to MRI-guided positioning of the needle the correct needle localization by the nerve root was confirmed with saline injection to nerve root channel and single-shot fast spin echo (SSFSE) imaging. The MRI guidance allowed adequate needle positioning in all but 1 case (98.5%). This failure was caused by degeneration-induced changes in anatomy. Of patients, 51.5% had good to excellent effect with regard to radicular pain from the procedure, 22.7% had temporary relief, 21.2% had no effect, and in 4.5% the pain worsened. Our results show that MRI guidance is accurate and safe in performing nerve root infiltration at lumbosacral area. The results of radicular pain relief from nerve root infiltration are comparable to CT or fluoroscopy studies on the subject.

Adult↗

PubMed1999

Screening applications for MRI in the detection of upper abdominal disease: comparative study of non-contrast-enhanced single-shot MRI and contrast-enhanced helical CT.

PURPOSE: To compare the value of 'push-button' single-shot non-contrast-enhanced MRI and contrast-enhanced helical CT for detection of upper abdominal disease. METHODS: In 120 patients, images obtained with non contrast-enhanced single-shot MRI (T2: double echo HASTE, and T1: turbo FLASH) and contrast-enhanced helical CT were compared. Lesions or abnormalities were divided in 8 anatomical categories (1: liver; 2: pancreatobiliary; 3: kidney/adrenal gland; 4: retroperitoneum; 5: vascular; 6: spleen; 7: gastrointestinal tract and peritoneum; 8: base of thorax) and classified as follows: 2: seen at MRI only; 1: better seen at MRI; 0: no difference; -1: better seen at CT; -2: seen at CT only. Also recorded were the 'door-to-door' examination times. RESULTS: Of a total of 629 abnormalities, 594 were detected at MRI (94 %) and 536 at CT (85 %). CT offered better results in two categories only: retroperitoneum (mean score: -0.68) and vascular (mean score -0.87). Mean examination times were 19 min for CT and 14.8 min for MRI. CONCLUSION: Unenhanced single-shot MRI is a valuable first step of a comprehensive upper abdominal MR exam and may even be the final step in many patients.

Abdomen↗

PubMed2001

MRI-guided trephine biopsy and fine-needle aspiration in the diagnosis of bone lesions in low-field (0.23 T) MRI system using optical instrument tracking.

The purpose of this study was to evaluate the feasibility of MRI-guided bone biopsy with optical instrument tracking and evaluate advantage of combined fine-needle aspiration (FNA) with trephine biopsy. Twenty trephine bone biopsies and 13 FNAs were performed under MRI and CT guidance in 14 patients. Informed consent was obtained from all patients. The evaluation of diagnostic accuracy was achieved by comparing the histopathological and cytological diagnosis with current or final diagnosis made during 6-month clinical follow-up. A 0.23-T open MRI scanner with interventional tools (Outlook Proview, Marconi Medical Systems, Cleveland, Ohio) was used. A surface coil was used. For trephine biopsy MRI-compatible bone biopsy set (Daum medical, Schwerin, Germany) was used. The FNA was performed with MRI compatible 20-G needle (Cook, Bloomington, Ind.). The diagnostic accuracy of MRI-guided trephine biopsy was 95%. The FNA sample diagnosis concurred with the histological in 54%. Our results show that MRI guidance in bone biopsies is accurate and safe. It is comparable to CT-guided or open biopsy. The role of combined FNA with bone biopsies remains controversial.

Biopsy↗

PubMed2005

Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI.

We retrospectively evaluated magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas. We obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on the basis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity on T2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneous high signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomas lesions. (d) CI curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100-300 s, then sustains the plateau or decreases gradually to 600-900 s, while the other increases relatively rapidly, reaches a plateau at 90-120 s, then decreases relatively rapidly to 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case with glandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, and unicystic type.

Adolescent↗