Magnetic resonance imaging-guided diskography and diagnostic lumbar 0.23T MRI: an assessment study.

PURPOSE: To describe the in vivo appearance of magnetic resonance imaging (MRI) diskograms of normal and degenerated lumbar intervertebral disks, and to evaluate the differences in imaging findings between sequential diagnostic MRI and MRI diskography. MATERIAL AND METHODS: Nine consecutive patients underwent MRI-guided diskography in order to determine possible pain provocation during puncture and contrast medium injection. All patients had preceding clinical suspicion of lumbar diskogenic pain and findings of lumbar disk degeneration in diagnostic (MRI, computed tomography (CT), plain radiography). A 0.23T open MRI scanner with interventional tools was used for imaging and instrument guidance. On all patients, a complementary diagnostic MRI study of the lumbar spine before and after the MRI-guided disk injection was performed, and subsequent axial MRI diskograms were obtained. RESULTS: A total of 25 disk punctures were initialized, and 25 MRI diskograms were obtained and their expression described. There was a correlation between the degenerative disk findings visualized by diagnostic MRI and MRI diskograms. CONCLUSION: The use of gadolinium contrast media in MRI-guided diskography enables the evaluation of MRI diskograms. Our results suggest that MRI-guided diskography can be used to substitute conventional diskography or CT-diskography and as an augmenting method to assess diagnostic information upon degenerative processes of the lumbar spine.

Sacro-iliac joint arthrography in low back pain: feasibility of MRI guidance.

OBJECTIVE: Evaluation of the feasibility of MR-guidance in sacro-iliac joint arthrography in patients whose low back pain is suspected to arise from the sacro-iliac joint (SIJ). METHODS AND PATIENTS: Twenty patients with low back pain underwent MR-guided sacro-iliac joint arthrography. Needles made from titanium (size 20 G, MDTech, USA) were used. For image guidance a 0.23T open-configuration C arm magnet (Proview, Marconi Medical Systems, USA) with special interventional hardware and software package (I-Path 200, Marconi Medical Systems) containing an MR compatible in-room console, large-screen (36") display, optical navigator and accompanying software with dedicated sequences was used. No other image guidance modalities were used. RESULTS: MR-guided SIJ arthrography was successfully performed in all twenty patients without complications. The optimal imaging sequence both for preoperative and intraoperative images was 3D-Gradient Echo sequence. The dispersal of the injected saline and anaesthetic could be determined inside the joint in all cases with heavily T2-weighted fast spin echo sequence. In the present study, 60% of the patients had significant reduction of pain after sacro-iliac joint arthrography and sacro-iliac joint was considered to be the source of patients low back pain in these patients. CONCLUSION: The present study shows that MR guidance with open configuration low field scanner is an accurate guiding method for sacro-iliac joint arthrography.

Plasma and pericardial fluid natriuretic peptide levels in postinfarction ventricular dysfunction.

AIMS: In the present study we examined plasma and pericardial fluid ANP and BNP concentrations in postinfarction ventricular dysfunction. The association of peptide levels to left ventricular (LV) dysfunction and to the localization of the myocardial infarction (MI) was studied. METHODS AND RESULTS: Plasma and pericardial fluid samples were obtained from 37 patients undergoing coronary bypass surgery. According to the ECG and preceding coronary angiography, the patients were divided into three groups: previous anterior myocardial infarction (MI) (n=12), previous inferior/posterior MI (n=15) and no history of MI (n=10). When compared to the control group with no MI, the patients with anterior MI had elevated plasma ANP and BNP (134+/-13 vs. 81+/-15 pg/ml, P<0.01 and 95+/-10 pg/ml vs. 26+/-8 pg/ml, P<0.01, respectively) and pericardial fluid BNP (473+/-60 pg/ml vs. 57+/-8 pg/ml, P<0.001) levels. The plasma natriuretic peptide concentrations were not increased in the patients with inferior/posterior MI, but the pericardial fluid BNP concentrations were greater than in the patients with no history of MI (129+/-35 pg/ml vs. 57+/-8 pg/ml, P<0.05). Six of the 12 patients with previous anterior MI had LVEF> or =45%. Despite their normal LV systolic function, these patients had increased plasma and pericardial fluid BNP levels when compared to the group with no history of MI (68+/-18 pg/ml vs. 26+/-8 pg/ml, P<0.05 and 534+/-258 pg/ml vs. 57+/-8 pg/ml, P<0.01, respectively). CONCLUSIONS: Previous anterior myocardial infarction was associated with increased cardiac BNP production even if the LV systolic function was normal (LVEF> or =45%). The high pericardial fluid BNP concentrations in postinfarction patients suggest that the BNP synthesis and release are augmented in the ventricular myocardium independent from the LVEF.

Nerve root infiltration of the first sacral root with MRI guidance.

The purpose of this clinical trial was to describe the methodology and evaluate the accuracy of optical tracking-based magnetic resonance (MR)-guided infiltration of the first sacral (S1) root. Thirty-five infiltrations were performed on 34 patients with a 0. 23-T open C-arm magnet installed in a fully equipped operation room with large-screen (36 inches) display and optical navigator utilizing infrared passive tracking. T1 and T2 fast spin-echo (FSE) images were used for localizing the target and fast field echo for monitoring the procedure. Saline as contrast agent in single-shot (SS)FSE images gave sufficient contrast-to-noise ratio. Twenty-four patients had unoperated L5/S1 disc herniation, and 10 had S1 root irritation after failed back surgery. Needle placement was successful in 97% of the cases, and no complications occurred. Outcome was evaluated 1-6 months (mean 2.2 months) after the procedure and was comparable to that of other studies using fluoroscopy or computed tomography guidance. MR-guided placement of the needle is an accurate technique for first sacral root infiltration.

Catecholamines in pericardial fluid of normotensive, spontaneously hypertensive and reserpine-treated rats.

In this study our aims were to investigate the presence and source of catecholamines in pericardial fluid of normotensive, reserpine-treated and spontaneously hypertensive rats. We found that noradrenaline is the only detectable catecholamine present in rat pericardial fluid. The effect of reserpine 6, 12, and 214 h after pre-treatment with 5 mg kg(-1) (8.2 micromol kg(-1)) i.p. shows that the concentration of noradrenaline in pericardial fluid reflects the amount of noradrenaline released within the heart rather than the amount of noradrenaline in plasma. Using spontaneously hypertensive rats (SHR) as a model for primary hypertension we could show that the level of pericardial noradrenaline is approximately threefold in the pericardial fluid of the SHRs when compared to respective values of age-matched normotensive Wistar-Kyoto rats (WKY), suggesting that there was an increased noradrenaline overflow in the hearts of the SHRs. In conclusion, determination of the noradrenaline concentration in the pericardial fluid might provide a new method for estimating the release of noradrenaline in the heart.

High concentrations of atrial natriuretic peptide and brain natriuretic peptide in rat pericardial fluid and their reduction by reserpine in vivo.

We determined concentrations and molecular sizes of natriuretic peptides in rat pericardial fluid and plasma by use of specific radioimmunoassays (RIA) and gel filtration HPLC. Our study shows that pericardial fluid forms a local extracellular storage of immunoreactive (ir) atrial natriuretic peptide (irANP) and brain natriuretic peptide (irBNP) near the heart where these peptides can be found in high concentrations in vivo. The concentrations of irANP, irBNP and NH2-terminal fragment of proANP (irNT-proANP) in pericardial fluid were 9.8 +/- 3.7, 0.49 +/- 0.47 and 28.9 +/- 11.8 nmol/l, respectively. IrBNP had the lowest (20 +/- 11) and irANP the highest (90 +/- 32) concentration ratio between pericardial fluid and plasma. The elution positions of irANP, irBNP and irNT-proANP in pericardial fluid and plasma were similar as examined by gel filtration HPLC. Furthermore, we show that the reduction of noradrenaline content of the heart muscle by reserpine reduces concentration of irANP in pericardial fluid by 39.6% and in plasma by 30.3% when compared to respective control group values. The concentration of irBNP is reduced by 44.1% in pericardial fluid but in plasma its reduction was not statistically significant. Vasoactive peptides released into the interstitial space and from there into pericardial fluid may have a more active role in the regulation of cardiac function than previously considered.