3.0 Tesla magnetic resonance imaging: A new standard in liver imaging?

An ever-increasing number of 3.0 Tesla(T) magnets are installed worldwide. Moving from the standard of 1.5 T to higher field strength implies a number of potential advantage and drawbacks, requiring careful optimization of imaging protocols or implementation of novel hardware components. Clinical practice and literature review suggest that state-of-the-art 3.0 T is equivalent to 1.5 T in the assessment of focal liver lesions and diffuse liver disease. Therefore, further technical improvements are needed in order to fully exploit the potential of higher field strength.     

Diagnostic imaging in Crohn’s disease: comparison of magnetic resonance imaging and conventional imaging methods

Conventional enteroclysis remains the method of choice in the diagnosis of inflammatory small bowel disease. The reported sensitivity rates, however, for the diagnosis of extraintestinal processes, such as fistulae and abscesses, are moderate. Computed tomography (CT) is the method of choice for the diagnosis of extraintestinal complications. The anatomical designation of the affected bowel segment may, however, prove difficult due to axial slices, and the applied radiation dose is high. The use of magnetic resonance imaging (MRI) in the diagnosis of inflammatory small bowel disease is a relatively new indication for the method; prerequisites were the development of breathhold sequences and phased array coils. Optimized magnetic resonance tomographic imaging requires a combined method of enteroclysis and MRI, which guarantees an optimal filling and distension of the small bowel. The high filling volume leads to a secondary paralysis of the small bowel and avoids motion artifacts. In a trial of 84 patients with histological and endoscopic correlation the sensitivity in diagnosing inflammatory bowel disease was 85.4% for enteroclysis and 95.2% for MRI, and the specificity was 76.9% for enteroclysis and 92.6% for MRI. As none of the abscesses was diagnosed with enteroclysis, the sensitivity was 0% for enteroclysis, but 77.8% for MRI. The sensitivity in diagnosing fistulae was 17.7% for enteroclysis and 70.6% for MRI. In summary, MRI can detect the most relevant findings in patients with inflammatory small bowel disease with an accuracy superior to that of enteroclysis. Accepted: 31 March 2000     

Imaging in the diagnosis and management of peripheral psoriatic arthritis—The clinical utility of magnetic resonance imaging and ultrasonography

Psoriatic arthritis (PsA) is an inflammatory joint disease characterised by the presence of arthritis and often enthesitis and/or spondylitis in patients with psoriasis. However, it presents a wide range of disease manifestations in various patterns. Imaging is an important part of management of PsA, and is used for multiple reasons including establishing/confirming a diagnosis of inflammatory joint disease, determining the extent of disease, monitoring activity and damage, assessing therapeutic efficacy, and identifying complications of disease or treatment, in the setting of clinical practice or clinical studies. Magnetic resonance imaging (MRI) allows detailed assessment of all peripheral and axial joints involved in PsA, and can visualise both inflammation and structural changes. Ultrasonography (US) can visualise many of the peripheral heterogeneous tissue compartments affected by PsA. In contrast to MRI, US is not useful for assessing axial involvement in the spine and sacroiliac joints. In this paper, we will provide an overview of the status, strengths and limitations of MRI and US in peripheral PsA in routine clinical practice and clinical trials.     

Is intraoperative ultrasonography during partial hepatectomy still necessary in the age of magnetic resonance imaging?

BACKGROUND/AIMS: The aim of our study was to determine if intraoperative ultrasonography is still necessary in the time of magnetic resonance imaging. METHODOLOGY: Our prospective study comprised 122 patients (82% with malignant tumors) undergoing partial hepatectomy with preoperative magnetic resonance imaging, done at the same institution using a standardized liver protocol as well as intraoperative ultrasonography performed in a systematic fashion. RESULTS: Seventeen additional malignant lesions in 16/122 patients (13.1%) were found intraoperatively [7 visible, 2 palpable, 8 (6.6%) diagnosed by intraoperative ultrasonography only; mean size: 1.5 cm; left:right lobe = 11:6]. This caused a change in surgical strategy in 14 patients (11.5%), including 6 patients (4.9%) with lesions seen on intraoperative ultrasonography only. The average total number of lesions in those patients was 3.4. Ten lesions (7 benign, 3 malignant) described on magnetic resonance imaging were not found on intraoperative ultrasonography, but no unnecessary operations resulted from this. In one patient additional micrometastases seen neither on magnetic resonance imaging nor on intraoperative ultrasonography were found histologically. CONCLUSIONS: Intraoperative ultrasonography is still worthwhile as it remains unsurpassed in the ultimate determination of the number of lesions, tumor extension and anatomical resolution. However, in the course of time its benefits may decrease further due to ongoing improvement of preoperative imaging.     

Optimal b value of diffusion-weighted imaging on a 3.0T magnetic resonance scanner in Crohn’s disease

AIM: To determine the optimal b value of diffusion-weighted imaging for detecting active inflammation in Crohn’s disease.METHODS: Thirty-one patients clinically diagnosed with active Crohn’s disease were referred for magnetic resonance examination. All patients were scanned on a 3.0T magnetic resonance scanner using the same protocol involving four different b values (800, 1500, 2000 and 2500 s/mm²). The diagnostic effect of diffusion-weighted imaging was evaluated and compared with endoscopic findings. The diffusion-weighted image quality of four b value groups was evaluated and apparent diffusion coefficient was measured for both normal and inflammatory intestinal segments.RESULTS: The contrast-to-noise ratio and signal-to-noise ratio were not satisfied when b value 2000 or 2500 s/mm² was adopted (36.52 ± 14.95 vs 34.78 ± 24.83, P > 0.05; 53.58 ± 23.45 vs 47.58 ± 29.67, P > 0.05). The qualitative image quality was not enough to meet diagnostic requirement. No matter which b value was chosen, the apparent diffusion coefficient of inflammatory intestinal segments was significantly lower than that of normal intestinal segments (1.38 ± 0.28 vs 2.00 ± 0.38, P < 0.01; 1.09 ± 0.20 vs 1.50 ± 0.28, P < 0.01; 0.95 ± 0.19 vs 1.34 ± 0.28, P < 0.01; 0.88 ± 0.14 vs 1.20 ± 0.21, P < 0.01). The lesion detection rate (90.32%), diagnostic sensitivity (81.18%) and specificity (95.10%) would be appropriate when b value 1500 s/mm² was adopted.CONCLUSION: High b value is suitable for intestinal DW examination on a high field MR scanner.     

Mechanism of action of octreotide in acromegalic tumours in vivo using dynamic contrast-enhanced magnetic resonance imaging

Context Octreotide causes significant tumour shrinkage in patients with acromegaly but the exact mechanism of action is unclear in vivo. Objective To determine the mechanism of action of octreotide in vivo using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Design Five patients with acromegaly were treated with octreotide as primary medical therapy. DCE-MRI was done at baseline and 24 weeks. Local ethical committee approval was granted. Setting Study was done in a tertiary care centre. Patients Five patients with newly diagnosed acromegaly were recruited. Intervention Patients were started on subcutaneous octreotide and DCE-MRI was done on 0 and 24 weeks. Main outcome measures Amplitude of contrast intake, exchange rate and maximum enhancement index of tumour tissue was compared before and after treatment. Results Amplitude of contrast intake (9.87 ± 3.52 vs. 4.97 ± 1.96 P ≤ 0.05) and exchange rate (6.27 ± 1.57 vs. 1.63 ± 0.76 P value ≤ 0.01) were significantly higher at baseline in adenoma compared to normal pituitary tissue but was comparable to normal pituitary tissue after treatment. There was a significant decrease in amplitude of contrast intake and exchange rate which relates to functional vascularity of adenoma at 24 weeks compared to baseline (P-values 0.026 and 0.002 respectively) but there were no significant changes in the normal pituitary tissue. Conclusion DCE-MRI in acromegalic tumours treated with octreotide showed a significant reduction in functional vascularity after octreotide therapy compared to baseline in pituitary adenomas. This supports the antiangiogenic action of somatostatin analogue therapy in vitro, but it remains unclear if this mechanism is important clinically in analogue pre-treatment reducing the effect of radiotherapy on these pituitary tumours.     

A high-resolution magnetic resonance imaging study of distal interphalangeal joint arthropathy in psoriatic arthritis and osteoarthritis: are they the same?

OBJECTIVE: Distal interphalangeal (DIP) joint arthropathy is characteristic of both psoriatic arthritis (PsA) and osteoarthritis (OA), but the microanatomic basis for DIP joint localization is poorly understood. This study used high-resolution magnetic resonance imaging (MRI) to investigate the basis for hand disease localization in both conditions. METHODS: Twenty patients matched for disease duration (10 with DIP joint PsA and 10 with DIP joint OA) and 10 normal control subjects were scanned with a 1.5T MRI scanner utilizing a high-resolution 23-mm diameter surface coil with displayed pixel dimensions of 80-100 mum. Images were obtained precontrast and postcontrast, and all joint structures, including ligaments, tendons, and entheses, were evaluated by 2 independent assessors. RESULTS: PsA could be distinguished from OA on the basis of more severe inflammation in the collateral ligaments and the extensor tendons and more severe changes at the corresponding DIP joint entheseal insertions. A much greater degree of extracapsular enhancement, with diffuse involvement of the nailbed and diffuse bone edema without cartilage damage, was also typical of PsA. Compared with the normal controls, the OA cohort exhibited prominent ligament and entheseal changes, but with much less contrast enhancement than in PsA and less bone involvement at the insertions. CONCLUSION: These findings suggest prominent inflammatory changes in ligament, tendon, enthesis, and adjacent bone in the DIP joint disease of PsA patients. Involvement of the same structures is common in the DIP joints of OA patients, but inflammatory changes are much less marked. These findings are potentially important for a better understanding of arthritis in humans.     

Magnetic resonance imaging and proton magnetic resonance spectroscopy in neuro-Behçet's disease

OBJECTIVE: Neuro-Behcet's disease (NBD) is one of the most serious complications of Behcet's disease (BD). Proton magnetic resonance spectroscopy (1H MRS) has been proved to be useful in detecting neuro-metabolic abnormalities in various diseases affecting the brain. In this study, we attempted to characterize the magnetic resonance imaging (MRI) findings in Korean patients with NBD and then examined the usefulness of 1HMRS in evaluating the MRI-negative brain area of NBD patients. METHODS: We performed brain MRI in 18 BD patients with neurologic symptoms and signs. Seven NBD patients without thalamic lesions and 8 healthy controls underwent brain 1H MRS, in which an 8 ml voxel was placed in the left thalamus and the N-acetylaspartate (NAA)/creatine (Cr) ratio was measured. RESULTS: Fourteen of 18 BD patients were diagnosed as having NBD and 12 NBD patients (86%) had brain lesions on MRI. Most lesions were of high signal intensity on T2-weighted images and located in the midbrain, pons, basal ganglia, and white matter. On 1H MRS, the thalamic area without gross abnormalities on MRI showed a significantly lower NAA/Cr ratio in NBD patients compared to healthy controls (1.07 +/- 0.08 versus 1.54 +/- 0.27, P < 0.01). In 2 NBD patients, the NAA/Cr ratios, monitored serially, were normalized along with clinical improvement 6 months after treatment with prednisolone and immune suppressive agents. CONCLUSION: MRI is a very sensitive diagnostic method for NBD, and 1H MRS may be useful for the early detection and follow-up of MRI-negative NBD.     

Evaluation of cartilage degradation in arthritis using T1ρ magnetic resonance imaging mapping

T1ρ magnetic resonance imaging (MRI) can be used to map proteoglycan (PG) loss in cartilage. Here, we used T1ρ MRI to map cartilage degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). Tissue samples were obtained from five RA patients and 14 OA patients following total knee arthroplasty (TKA). Three parameters were measured: First, macroscopic grading of cartilage sample tissues was performed on a 5-grade scale (G0: normal, G1: swelling, G2: superficial fibrillation, G3: deep fibrillation, G4: subchondral bone exposure). Second, semi-quantitative values of PG were assessed by measuring the optical density of Safranin-O-stained paraffin sections that had been digitally photographed. Third, cartilage was divided into superficial and deep layers and the T1ρ values were quantified. T1ρ values of OA and RA in the superficial layers showed significant differences between groups (G0/1 and G0/2 for OA; G0/2 and G1/2 for RA). In the deep layers, T1ρ values of OA and RA also differed significantly between groups. In both the superficial and deep layers, there was a significant correlation between the mean T1ρ values and macroscopic grading (P < 0.01 for OA, P < 0.001 for RA). We found a negative correlation between the score of Safranin-O staining and T1ρ values (r = -0.61 for OA, r = -0.79 for RA). In addition, RA subjects had significantly higher T1ρ values than OA subjects of similar morphologic grade. In conclusion, T1ρ MRI is able to detect and map the early stages of cartilage degradation in OA and RA. This method is reliable and useful for the evaluation of macromolecular changes in arthritic cartilage.     

Cardiac effects of 3 months treatment of acromegaly evaluated by magnetic resonance imaging and B-type natriuretic peptides

Long-term treatment of acromegaly prevents aggravation and reverses associated heart disease. A previous study has shown a temporary increase in serum levels of the N-terminal fraction of pro B-type natriuretic peptide (NT-proBNP) suggesting an initial decline in cardiac function when treatment of acromegaly is initiated. This was a three months prospective study investigating short-term cardiac effects of treatment in acromegalic patients. Cardiac function was evaluated by the gold standard method cardiac magnetic resonance imaging (CMRI) and circulating levels of B-type natriuretic peptides (BNP and NT-proBNP). CMRI was performed at baseline and after 3 months of treatment. Levels of IGF-I, BNP and NT-proBNP were measured after 0, 1, 2 and 3 months. Eight patients (5 males and 3 females, mean age 53 ± 12 years (range 30–70)) and 8 matched healthy control subjects were included. Median IGF-I Z-score decreased from 4.5 (range 2.5–6.4) to 2.3 (−0.1 to 3.3). At baseline the patients had increased left ventricle mass index (LVMI) compared to control subjects (ΔLVMI 35 g/m² (95% CI 8–63 g/m², P = 0.016). After 3 months of treatment there was an increase in end-diastolic volume index EDVI (ΔEDVI 9 mL/m² (95% CI 3–14), P = 0.007) and an increase in levels of BNP (median (ranges) 7 (0.58–286) vs. 20 (1–489) pg/mL, P = 0.033) and of NT-proBNP (63 (20–1004) vs. 80 (20–3391) pg/mL, P = 0.027). Assessed by the highly sensitive and precise CMRI method, 3 months treatment of acromegaly resulted in an increase in EDVI, and increased levels of BNP and NT-proBNP suggesting an initial decrease in cardiac function.     

A high‐resolution magnetic resonance imaging study of distal interphalangeal joint arthropathy in psoriatic arthritis and osteoarthritis: Are they the same?

Objective

Distal interphalangeal (DIP) joint arthropathy is characteristic of both psoriatic arthritis (PsA) and osteoarthritis (OA), but the microanatomic basis for DIP joint localization is poorly understood. This study used high‐resolution magnetic resonance imaging (MRI) to investigate the basis for hand disease localization in both conditions.

Methods

Twenty patients matched for disease duration (10 with DIP joint PsA and 10 with DIP joint OA) and 10 normal control subjects were scanned with a 1.5T MRI scanner utilizing a high‐resolution 23‐mm diameter surface coil with displayed pixel dimensions of 80–100 μm. Images were obtained precontrast and postcontrast, and all joint structures, including ligaments, tendons, and entheses, were evaluated by 2 independent assessors.

Results

PsA could be distinguished from OA on the basis of more severe inflammation in the collateral ligaments and the extensor tendons and more severe changes at the corresponding DIP joint entheseal insertions. A much greater degree of extracapsular enhancement, with diffuse involvement of the nailbed and diffuse bone edema without cartilage damage, was also typical of PsA. Compared with the normal controls, the OA cohort exhibited prominent ligament and entheseal changes, but with much less contrast enhancement than in PsA and less bone involvement at the insertions.

Conclusion

These findings suggest prominent inflammatory changes in ligament, tendon, enthesis, and adjacent bone in the DIP joint disease of PsA patients. Involvement of the same structures is common in the DIP joints of OA patients, but inflammatory changes are much less marked. These findings are potentially important for a better understanding of arthritis in humans.

     

Clinical utility of cardiac magnetic resonance imaging in Churg–Strauss syndrome: case report and review of the literature

We describe a case of an individual with Churg–Strauss syndrome who presented with a cerebrovascular accident (CVA) secondary to left ventricular intracavitary thrombi. Noninvasive cardiovascular imaging using transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) was used to identify the cardioembolic source of CVA. The clinical utility of CMR in the management of patients with Churg–Strauss syndrome is reviewed.     

Disease activity in longstanding ankylosing spondylitis—a correlation of clinical and magnetic resonance imaging findings

We evaluated magnetic resonance imaging (MRI) changes in ankylosing spondylitis (AS) patients with longstanding disease and investigated whether there is any relationship between MRI findings and validated methods of disease assessment. A total of 34 AS patients with disease duration greater than 10 years were included in this observational cross-sectional study (26 men, 8 women). The main outcome measures were Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Global assessment (BASG), Bath Ankylosing Spondylitis Metrology Index (BASMI), MRI of the thoracic and lumbar spine (AS spi MRI A) and measurement of serum erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), plasma viscosity (PV) and immunoglobulin A (Ig A). The median scores for the acute lesions based on AS spi MRI A scoring system was 2.5 (0–4.12). The respective mean ESR and CRP were 36 (SD, 24.00) mm/h and 14.19 (SD, 24.00) mg/l with the median PV of 1.8 (1.75–1.87). The median BASG, BASFI and BASDAI were 4.55 (2.37–5.55), 4.40(2.31–5.47) and 4.32 (3.07–6.48), respectively. No significant correlations were found between the acute MRI scores and each of the clinical instruments and laboratory markers of inflammation. In this study, majority of AS patients with longstanding disease had very low AS spi MRI A scores or no evidence of spinal inflammatory lesions. Our study would suggest that MRI should be used along with other measures of disease activity in the assessment of symptomatic AS patients with longstanding disease.     

Persistent low grade synovitis without erosive progression in magnetic resonance imaging of rheumatoid arthritis patients treated with infliximab over 1?year

Disease remission is only reached by a minority of rheumatoid arthritis (RA) patients treated with infliximab. Radiological assessment reported in clinical trials support the view that even under persistent inflammatory activity there is no further structural damage. Magnetic resonance imaging (MRI) allows a highly accurate detection of synovitis, bone edema, and erosions, constituting the ideal instrument for the evaluation of treatment response. The goal of this study was to evaluate MRI changes over 1 year in RA patients treated with infliximab. Four RA patients refractory to methotrexate (MTX) therapy were treated with infliximab 3 mg/kg 8/8 weeks and followed up for 1 year. Disease Activity Score (DAS28) was measured in the day of each infliximab administration. MRI was performed at baseline, 3 months, and 1 year. A simplified OMERACT RA MRI scoring (RAMRIS) was applied to the dominant wrist: synovitis (0–3) was measured in the intercarpal–carpometacarpal joints (CMTJ); bone edema (0–39) and erosions (0–130) in the base of the metacarpal and wrist bones. Baseline DAS28 was superior to 3.2 in all patients (ranging from 4.8 up to 6.2). At 14 weeks, DAS28 was still superior to 3.2 (ranging from 3.5 up to 4.6) and at 46 weeks all patients have responded, however without having achieved clinical remission, as DAS28 was still above 2.6 (ranging from 2.6 up to 3.4). MRI showed that synovitis was reduced in all patients to a score of 1, bone edema was slightly reduced (10% reduction), and erosive score was unchanged (baseline values ranging from 2 up to 20). Despite persistent low disease activity, these four RA patients treated with infliximab had stable simplified RAMRIS erosive scores over 1 year. These results support the view that there might be an uncoupling process between inflammation and bone erosions when tumor necrosis factor alpha is targeted in RA.     

What is the fate of erosions in early rheumatoid arthritis? Tracking individual lesions using x rays and magnetic resonance imaging over the first two years of disease

OBJECTIVES: To investigate the progression of erosions at sites within the carpus, in patients with early rheumatoid arthritis (RA), using magnetic resonance imaging (MRI) and plain radiology over a two year period. METHODS: Gadolinium enhanced MRI scans of the dominant wrist were performed in 42 patients with RA at baseline (within six months of symptom onset) and one year. Plain wrist radiographs (x rays) and clinical data were obtained at baseline, one year, and two years. Erosions were scored by two musculoskeletal radiologists on MRI and x ray at 15 sites in the wrist. A patient centred analysis was used to evaluate the prognostic value of a baseline MRI scan. A lesion centred analysis was used to track the progression of individual erosions over two years. RESULTS: The baseline MRI erosion score was predictive of x ray erosion score at two years (p=0.004). Patients with a "total MRI score" (erosion, bone oedema, synovitis, and tendonitis) > or =13 at baseline were significantly more likely to develop erosions on x ray at two years (odds ratio 13.4, 95% CI 2.65 to 60.5, p=0.002). Baseline wrist MRI has a sensitivity of 80%, a specificity of 76%, a positive predictive value of 67%, and a high negative predictive value of 86% for the prediction of wrist x ray erosions at two years. A lesion centred analysis, which included erosions scored by one or both radiologists, showed that 84% of baseline MRI erosions were still present at one year. When a more stringent analysis was used which required complete concordance between radiologists, all baseline lesions persisted at one year. The number of MRI erosion sites in each patient increased from 2.1 (SD 2.7) to 5.0 (4.6) (p<0.0001) over the first year of disease. When MRI erosion sites were tracked, 21% and 26% were observed on x ray, one and two years later. A high baseline MRI synovitis score, Ritchie score, and erythrocyte sedimentation rate were predictive of progression of MRI erosions to x ray erosions over one year (p=0.005, 0.01, and 0.03 respectively), but there was no association with the shared epitope. Progression of MRI erosions to x ray erosions was not seen in those with transient polyarthritis. CONCLUSIONS: MRI scans of the wrist, taken when patients first present with RA, can predict radiographic erosions at two years. MRI may have a role in the assessment of disease prognosis and selection of patients for more or less aggressive treatment. However, only one in four MRI erosions progresses to an x ray erosion over one year, possibly owing to healing, observer error, or technical limitations of radiography at the carpus. Progression of MRI erosions to x ray erosions is greatest in those with high baseline disease activity.