[Cardiac MRI with SENSE technology: study of ventricular and valvular functionality in 30 patients].

PURPOSE: The latest innovation in MR imaging is SENSE (SENSitivity Encoding), a technology providing an important solution for the time necessary for signal encoding. In the SENSitivity Encoding (SENSE) approach, an array of multiple, simultaneously operated receiver coils is used for signal acquisition. In particular, the efficacy of SENSE technology is able to reduce the number of phase encodings by a factor (named R factor or Reduction factor) and to evaluate the same k space with fewer readout lines obtaining higher spatial and temporal resolution. MATERIALS AND METHODS: An heterogeneous group of 30 patients with a variety of clinically proven diagnoses underwent Cardiac MR with SENSE technology to evaluate the technique's diagnostic efficacy. The sequences used were "Balanced" Ultrafast Gradient Echo (B-FFE) characterised by a hyper-intense blood signal with multislice multiphase and single slice multiphase acquisitions. RESULTS: In addition to reducing scan times, SENSE technology improved spatial and temporal resolution (40 frames/cardiac cycle) providing optimal dynamic evaluation of valve structures and wall kinesis. Furthermore, the use of the SENSE technique with B-FFE sequences (sB-FFE) enabled the qualitative evaluation of abnormal blood movements and transvalvular flows. CONCLUSIONS: The considerable time savings allowed by SENSE technology and the clear improvement in image quality constitute a step forward in cardiac MR imaging. The possibility of executing morphologic, dynamic, perfusional and spectroscopic studies in the same MR examination session with short acquisition times and good image quality are becoming more feasible.

MRI lung perfusion 2D dynamic breath-hold technique in patients with severe emphysema.

BACKGROUND: Our aim was to prospectively evaluate a semi-quantitative pulmonary perfusion MR technique using a breath-hold 2D dynamic sequence in patients with severe pulmonary emphysema. MATERIALS AND METHODS: Thirty patients with severe emphysema were studied with pulmonary perfusion MRI. Results were compared with those obtained through lung scintigraphy, considered as the gold standard technique. We used Fast Field Echo (FFE) pulse sequences in the coronal and sagittal planes, with paramagnetic contrast agent administration. Ten healthy volunteers were studied as the control group. Three thoracic radiologists independently reviewed all the subjects, evaluating the site and entity of perfusional defects. Peak intensity and apparent mean transit time were calculated. RESULTS: MRI showed high sensitivity (86.7%) and good specifity (80.0%) in detecting perfusional defects. We observed lower peak signal intensities in emphysematous regions. CONCLUSION: Lung perfusion MR is a potential alternative to Nuclear Medicine in the evaluation of severe pulmonary emphysema.

Vascular involvement in pancreatic neoplasm: a comparison between spiral CT and DSA.

The principal criterion for resectability of pancreatic carcinoma is the assessment of vascular involvement. In a prospective evaluation the ability of Spiral CT Angiography (CTA) to detect vascular involvement in 50 patients with pancreatic carcinoma, was proved; DSA was performed later in all patients. In 20 patients, without vascular involvement, a complete concordance was obtained. Of 30 patients with vascular involvement, there was complete concordance between CTA and angiography in 22 patients and discordance in 8 patients. CTA was superior in 2 cases with periadventitial infiltration and in 5 patients with splenoportal confluence thrombosis. DSA was superior in 1 case with infiltration of the superior mesenteric vein. After surgical evaluation, sensitivity of CTA and DSA was 97% and 77%, respectively, and the negative predictive values were 95% and 74%. As compared to DSA, CTA is more rapid and less invasive and can be considered the modality of choice for preoperative work-up of pancreatic neoplasm.

Pyriformis muscle syndrome: CT/MR findings in the percutaneous therapy with botulinic toxin.

PURPOSE: The aim of our study was to evaluate the diagnostic capabilities of computed tomography (CT) and magnetic resonance (MR) imaging in pyriformis syndrome (PS) and the long-term outcomes of CT-guided percutaneous treatment with botulinum. PS is a cause of sciatica and disability. The pain is usually increased by muscular contraction, palpation or prolonged sitting. MATERIAL AND METHODS: Thirty-four patients suffering from PS, suspected on the basis of clinical and electrophysiological criteria and after imaging examinations had excluded other causes of sciatic pain, had positive lidocaine tests and were treated by intramuscular injection of botulinum toxin type A (BTX-A) under CT guidance. MR sequences was performed in nine patients before treatment and after three months to evaluate the extent of muscle denervation. RESULTS: In 30 cases relief of symptoms was obtained after 5-7 days. In four patients insufficient pain relief warranted a second percutaneous treatment which proved clinically successful. No complications or side effects were recorded after BTX-A injection. The MR examination demonstrated a change in signal intensity of the muscle in seven patients due to denervation, whereas in the remaining two cases only atrophy was detected. Larger series are necessary to confirm these preliminary results. CONCLUSIONS: CT-guided BTX-A injection in the pyriformis muscle is an emergent and feasible technique that appears to yield excellent local therapeutic effects without the risk of imprecise injection.

Perfusion MRI of the lung: preliminary results in twenty healthy volunteers.

PURPOSE: This study attempted to assess the feasibility and the accuracy of lung contrast enhanced magnetic resonance (MR) perfusion imaging in the evaluation of 20 healthy volunteers and to correlate the intensity/time (I/T) curves with the pulmonary physiological criteria. MATERIAL AND METHODS: After an informed consensus, twenty no-smoker subjects, without any present or past pulmonary pathologies, were studied by means of an ultra-fast gradient echo sequence after a Gd-DTPA intravenous administration. The acquisitions were performed in coronal and sagittal planes, in supine and prone position, in breath holding. An ulterior acquisition was performed in only five cases immediately after 2-3 minutes of physical exercise. RESULTS: All the examinations, reviewed according to a visual score by three independent observers, resulted fairly interpretable. The I/T curves, obtained in post-processing evaluation, have the same trend in all cases and are correlated to the lung physiological criteria: the position changes of the examined subjects confirm the gravity dependence of perfusion; the study performed immediately after physical exercise showed a reduction of perfusion in the whole lung due to a transitory massive shift of blood mass from visceral to muscular districts. CONCLUSIONS: The extremely short acquisition and post-processing time coupled with a simple feasibility, the ability to detect physiological perfusional changes, the minimal invasivity indicate a potential clinical use of MR in the pulmonary perfusion defects evaluation.