MR evaluation of anterior cruciate ligament reconstruction with quadriceps tendon. Preliminary experience.

PURPOSE: Anterior cruciate ligament reconstructions are becoming increasingly frequent, and MRI has been shown to be the best imaging modality for the non-invasive assessment of surgical outcome. Use of the quadriceps tendon as a biological replacement for injured cruciate ligament is a recent innovation. This study evaluated by MRI the results of anterior cruciate reconstruction in 27 consecutive patients who underwent arthroscopic reconstruction with homologous quadriceps tendon. MATERIAL AND METHODS: MRI was carried out on 27 patients who had undergone anterior cruciate ligament reconstruction with the middle third of the homolateral quadriceps tendon. The examinations were performed on two MRI units: a permanent 0.2-Tesla dedicated magnet (Artoscan, Esaote Italy) and whole-body 1.5-Tesla superconducting magnet (Signa, GE Medical Systems Milwaukee, Winsconsin USA). Axial, sagittal and coronal images were acquired with SE, GE and STIR fat suppression sequences. The examinations were performed 1, 3, and 6 months post-operatively in 16 patients, and 1 and 3 post-operatively in 11 patients. The same arthroscopic surgical technique was employed in all patients, with 20 cases of tibial mono-tunnel femoral semi-tunnel, and 7 cases with tibial bi-tunnel technique. All patients were assessed by arthrometric and clinical tests after surgery. Bioabsorbable interference screws were used for tibial fixation in all patients and metallic interference screws were used for femoral graft fixation in 8 patients. RESULTS: In all cases MRI correctly visualised the tunnel positions, the articular portion and the bone-portion of the graft inside the tibial and femoral tunnels. The absence of paramagnetic artefacts in the tibia allowed complete visualisation on the axial, sagittal and coronal MRI images with optimal spatial and contrast resolutions. In 6 cases, the presence of metal residues from the surgical cutter prevented correct evaluation of femoral tunnel content. No new graft or articular lesions were found. In 18/27 cases peri-focal marrow edema around the tibial tunnel had disappeared 3 months after surgery. The process of synovial incorporation was judged to be correct in all cases. DISCUSSION: The use of anterior cruciate ligament reconstruction with the quadriceps tendon is a important innovation given the size of the harvested material and the possibility of completely filling the osseous tunnels, without interposition of synovial proliferation or fluid collection between tendon and bone, as confirmed by MRI. Furthermore, the use of non-metallic screws allows MRI evaluation of tunnel content and oedema in the spongy bone around the tunnel. The study of the double tibial tunnel requires specific obliqueness in the coronal plane scans. CONCLUSIONS: This arthroscopic technique for anterior cruciate ligament reconstruction allows thorough MRI evaluation of all portions of the transplant, and in particular those coursing within the tibia and femur. The absence of bone oedema around the tunnels and synovial proliferation within the tunnels may be predictive of faster healing and complete bone incorporation of the grafts.

Magnetic resonance imaging and different levels of iron overload in chronic liver disease.

The need for accurate and noninvasive evaluation of liver iron stores prompted us to evaluate the reliability of high-field magnetic resonance imaging equipment in liver patients with low or moderate siderosis, given the poor results obtained using systems operating at low field strength in such cases. Twenty patients with sporadic porphyria cutanea tarda and 28 with comparable chronic liver diseases (chronic hepatitis or cirrhosis) and moderate siderosis were compared with 10 patients with idiopathic or secondary hemochromatosis and 10 healthy controls. Plasma iron profile, ferritin concentration and liver iron concentration, determined with atomic absorption spectroscopy, were matched with the magnetic resonance parameters-namely, transverse relaxation time and the signal intensity for a given proton amount, obtained with equipment operating at a field strength of 1.5 T. Hemochromatosis patients with mean liver iron concentrations of 550 mumol/gm dry wt (vs. 10 mumol of controls) exhibited an impressive reduction in the signal intensity with respect to the other three groups, and this reduction prevented any further comparison with the same porphyria cutanea tarda and chronic liver disease groups, whose liver iron level was twice that of the controls. The signal intensity remained almost unchanged in the latter groups, whereas the transverse relaxation time was significantly reduced. Moreover, correlation with liver iron was significantly inverse in the case of the transverse relaxation time (n = 17, r = 0.62, p = 0.008) and direct in the case of the transverse relaxation rate. The transverse relaxation time values returned to normal in five patients who had completed an iron-depletion program.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone pulsating metastasis due to hypernephroma.

Bone pulsating metastasis due to hypernephroma is an exceptional occurrence. The authors present one case of bone pulsating metastasis due to hypernephroma localized in the proximal tibia. The primary renal lesion was located by ultrasonography and confirmed by CT scan.

Bone marrow infiltration in hairy cell leukemia after interferon therapy detected by magnetic resonance imaging.

Magnetic resonance imaging (MRI) can detect bone marrow infiltration by neoplastic cells in many hematological malignancies. We studied 10 patients affected by hairy cell leukemia (HCL) and treated with interferon (IFN) with both MRI and bone marrow biopsy. T1-weighted MR scans of femurs and pelvis proved to be effective to score hairy cell infiltration, while less information was obtained from the study of the lumbar vertebral column. A good correlation (less than 10% difference) was noted between biopsy and MRI in over 90% of cases. MR scans showed, in general, a higher grade of infiltration. MR scan, however, can be useful for monitoring the course of HCL and the response to the treatment. Moreover, MRI evaluating a large amount of tissue, can detect a nodular type of infiltration which can be missed in biopsy specimens.