[Magnetic resonance study of patellofemoral cartilage with a fat-suppressed T1-3D gradient-echo sequence: a comparison with other acquisition technics at medium field strength]. / Studio della cartilagine femoro-rotulea con Risonanza Magnetica mediante sequenza Gradient Echo-T1-3D con soppressione del segnale del tessuto adiposo: confronto con le altre tecniche di acquisizione con media intensità del campo.

PURPOSE: We compared GRE T1 3D FS sequence with other acquisition techniques available on medium field strength MR units (.5 T) in patellofemoral cartilage studies. MATERIAL AND METHODS: The imaging protocol scheduled Spin Echo (SE), Inversion Recovery (STIR), Gradient Echo (GRE), Turbo Spin Echo (TSE), Turbo-Inversion Recovery (Turbo-STIR), Gradient Spin Echo (GRASE) and Echo Planar (EPI) sequences, in some cases combined with Fat Suppression (FS) or Magnetization Transfer Contrast (MTC) sequences when suitable. In vitro studies were carried out for signal-to-noise ratio (SNR) evaluation, and in vivo on 10 healthy volunteers for contrast-to-noise ratio (CNR) evaluation between cartilage, bone marrow and fluid. The exams were carried out on MR equipment operating at .5 T, with 15 mT/m power gradients. RESULTS: In both in vitro and in vivo studies, GRE T1 3D FS sequences yielded better results in SNR and CNR than other sequences. The GRE T1 3D FS technique combines the advantages of the increased resolution of 3D images with the increased dynamic range of fat suppressed images, for better CNR between cartilage, fluid and bone marrow. CONCLUSION: GRE T1 3D FS sequences are the MR acquisition technique of choice in the assessment of the hyaline cartilage of the knee, even at medium field strength.

[Persistent coxalgia in the child. The value of magnetic resonance]. / Coxalgia persistente del bambino. Apporto della risonanza magnetica.

This study was aimed at assessing the Magnetic Resonance (MR) features of persistent hip pain in children. Twenty-six patients aged 1.6 to 15.2 years (mean: 6.5 years) were clinically selected for the study; at clinics, all patients had persistent hip pain after 10 days' therapy. All patients were examined with radiography, US and MRI at 0.5 T. SE T1-weighted sequences, with and without fat suppression (FS), SE T2-weighted and gradient echo (GE) T1-weighted-like (T1*) sequences were acquired on the coronal plane. Slices were 5 and 3 mm thick on SE and GE T1* sequences, respectively. Morphology and signal intensity of epiphysis, growth plate and metaphysis were prospectively studied with MRI. Clinical and/or imaging follow-up (3 months) was the reference standard in our study. Final diagnoses were: no evidence of alteration (n = 3), transient synovitis (n = 6), rheumatic fever (n = 3), Perthes' disease (n = 7), Meyer's dysplasia (dysplasia epiphysealis capitis femoris, DECF) (n = 2), early slipped capital femoral epiphysis (n = 2), incomplete fracture (n = 1), extraarticular cause of pain (muscular abscess, osteomyelitis) (n = 2). In 23 of 26 patients MRI confirmed clinical, radiographic and US findings. MRI was particularly helpful in making an unquestionable diagnosis in the other 3 cases; in a patient with suspected slipped capital femoral epiphysis MRI revealed an incomplete fracture, in a patient with suspected Meyer's dysplasia MRI revealed early Perthes' disease and finally in a patient with suspected transient synovitis MRI revealed Perthes' disease. To conclude, MRI allows the condition causing persistent hip pain to be assessed and accurately depicted, integrating clinical, radiographic and US findings and in some cases also changing diagnosis and therapy.