Contrast-enhanced three-dimensional MR angiography of neck vessels: does dephasing effect alter diagnostic accuracy?

The aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading.

Contrast-enhanced three-dimensional MR angiography in the assessment of subclavian artery diseases.

The purpose of this prospective study was to determine the potential diagnostic value of 3D breath-hold contrast-enhanced MRA (CEMRA) in the evaluation of subclavian artery pathology, and to compare CEMRA and digital subtraction angiography (DSA) findings. The study group included 50 patients with suspicion of subclavian artery pathology: 40 suspected steno-occlusive disease and 10 different vascular anomalies. The MRA examinations were performed on a 1.5-T system using fast 3D sequences. A fixed dose of 40 ml Gd-DTPA was administered at 2 ml/s after previous bolus tracking. Images were analyzed to assess: subclavian depiction; luminal changes; collateral branches; and feeders of arterial venous malformations (AVM). A multireader blinded fashion was used. The CEMRA revealed an optimal agreement with DSA findings in the different types of diseases. Sensitivity and specificity were 90 and 95%, respectively, in detecting steno-occlusive disease (including functional and arteritic stenoses), and 100 and 100%, respectively, in cases of vascular anomalies (dilation, kinking, anomalous origin and AVM). Contrast-enhanced MRA can be proposed as a non-invasive, robust technique for imaging subclavian pathologies with high diagnostic performance.

[Usefulness of opposed-phase gradient-echo technique in the diagnosis of occult lesions of the knee and comparison with traditional T1-weight sequences (in-phase)]. / Utilità della tecnica Gradient-Echo in opposizione di fase nel rilievo delle lesioni occulte del ginocchio e confronto con le sequenze T1-pesate tradizionali (in fase).

PURPOSE: To investigate the usefulness of opposed-phase gradient-echo (GRE) technique in detecting occult posttraumatic bone injuries in the knee. Occult injuries account for pain and, if not properly treated, may progress to severe chondral and bone damage. An early diagnosis provided by MRI can help avoid interventional procedures. MATERIAL AND METHODS: We submitted to MRI of the knee 51 patients (32 men and 19 women) with negative plain radiographic findings and at least one traumatic bone injury at MRI. MR examinations were performed with a 0.5 T unit and included a conventional SE or GRE T1-weighted sequence and an opposed phase GRE sequence on the coronal or sagittal plane (2-3 minutes acquisition). To assess the lesion number and conspicuity, images were retrospectively reviewed by two readers. Injury conspicuity was graded as: 0 (poorly visible), 1 (visible), and 2 (well visible). Marrow-to-injury signal intensity ratio was calculated in 30 patients: a ROI was positioned in the site of highest signal intensity and adjacent bone marrow and the ratio analyzed with Student's "t"-test. RESULTS: In-phase and out-of-phase images showed 71 injuries in 51 patients. Conventional (in-phase) imaging missed 6/71 lesions. Injury conspicuity on out-of-phase images was of grade 2 in 58 cases (81.6%) and of grade 1 in 13 cases (18.3%), versus 23 (32.3%) and 42 (59.1%), respectively, on conventional images. Injury conspicuity was graded as 0 in 6 cases (8.4%) on conventional images. Quantitative analysis of marrow-to-injury signal intensity ratio showed higher values for out-of-phase GRE than conventional images. CONCLUSION: Opposed-phase GRE are quick sequences available on all MR systems which appear superior to conventional T1-weighted images in detecting occult injuries in the knee. Injuries are more conspicuous because their signal intensity is lower due to the simultaneous presence of fat and water protons, which is typical of bone trauma, GRE sequences make a useful and rapid complement to T1-/T2-weighted fat saturation acquisitions in the study of the post-traumatic knee.

Endorectal coil MR imaging findings in hemospermia.

The purpose of this study was to illustrate the spectrum of abnormalities found at endorectal coil magnetic resonance (MR) imaging in patients with hemospermia. Ninety patients aged between 23 and 71 years (mean age 41 years) presenting with hemospermia underwent evaluation with endorectal coil MR imaging at 1.5 T. Duration of hemospermia ranged between 5 days and 4 years (mean 15 months). MR examination protocol included T1-weighted spin-echo (SE) and T2-weighted fast SE MR images obtained in the sagittal, coronal, and axial planes. Abnormalities were observed on endorectal-coil MR images in 49 of 90 patients (54%). Blood within the seminal vesicle or the ejaculatory duct was recognized in 23 of 90 patients (25%). Dilatation of the seminal vesicles or the ejaculatory duct was observed in 31 of 90 patients (34%). Cystic lesions were identified in 14 cases, eight of which involved the utriculus and six the ejaculatory duct. Calculi within the seminal vesicles were depicted in seven patients. No malignant disease was demonstrated. In conclusion, despite the evidence that hemospermia is most often a benign and self-limiting condition, we found that endorectal coil MR imaging can detect abnormal findings in more than half of the patients, and may be helpful in assessing the level at which hemorrhage occurred and in defining the cause of the disease.

[Calcaneal fractures: guidelines for the diagnosis with computerized tomography]. / Le fratture del calcagno: linee guida alla diagnosi con Tomografia Computerizzata.

We report on 31 cases of calcaneal fractures studied with CT according to the latest classification by the Italian Surgical Society of the Foot. Of the utmost importance is the radiologic assessment of the posterior facet and of the underlying bone, which make up the so-called talamus which bears most of the body weight. In our series, talamus fractures were the most frequent ones (26/31 cases): they are characterized by a main sagittal line, running obliquely and dividing the posterior surface and the bone into an anteromedial, or substentacular, fragment and a posterolateral, or tuberosity, fragment. According to fracture severity, the first differential criterion is the presence/absence of displacement and depression (type I fractures the latter, 6 cases in our series, and (types II and III the former, 20/26 cases in our series). Based on the degree of displacement and depression, fractures as classified as type II (10/26 cases) when only the lateral portion of the talamus is displaced and depressed, or as type III (10/26 cases) when the whole talamus is fragmented, displaced and depressed. Moreover, other worsening factors must be considered and B subgroups differentiated in types II and III fractures; these factors are: calcaneus-cuboid facet involvement, lateral wall fragmentation, posterior facet comminution, a small sustentacular fragment and a secondary frontal fracture interrupting the plantar cortex. Extra-talamic fractures, defined as such when isolated, rarely occur. Relative to the anterior apophysis, radiologic attention must be focused on fractures of the dorsal prominence, or beak, which are very often misdiagnosed. As regards the posterior tuberosity, its lateral dislocation must be studied because it may account for calcaneofibular impingement. CT exhibits excellent potentials, provided that slices are thin, acquired on the axial and coronal planes and that, as far as possible, sagittal reconstructions are used, the latter being very useful to depict talamic surface.

[Reconstruction of the anterior cruciate ligament using the patellar tendon: its magnetic resonance evaluation]. / La ricostruzione del legamento crociato anteriore con tendine rotuleo: valutazione con risonanza magnetica.

MRI of the knee was performed in 30 patients who had been submitted to arthroscopically-guided reconstruction of the anterior cruciate ligament from patellar tendon. The autograft structure was investigated and MR results were correlated with clinical findings. Partial/total meniscectomy had been carried out in 21/30 cases. The patients were imaged at various postoperative intervals (3-24 months) by means of an 0.5-T magnet (GE MR Max Plus) in full knee extension and internal rotation. Sagittal and axial T1-weighted images (slice thickness: 3 mm) were combined with real-time reconstruction which better demonstrated the whole graft. T2-weighted coronal images (slice thickness: 5 mm) were also acquired. In each patient the following clinical variables were considered: anterior drawer sign, Lachman test, pivot shift, degree of leg extension, and finally functional recovery. The following MR variables were then considered: structure and alignment of bone tunnels, structure and signal intensity of the graft, degree of synovial inflammation, structure and signal intensity of the posterior cruciate ligament and finally structure of the menisci and/or meniscal residues. Symptoms-MR correlation suggests that the different outcome of surgical reconstruction may depend on the correct alignment of the tibial and femoral bone tunnels and on good meniscal condition. Bone tunnels must be located on the same plane, posterior and parallel to the slope of the intercondylar roof, since angulation causes the latter to impact the graft during knee extension, with inflammation and risk for rupture. As for menisci, tiny residues or total ablation overload tha graft, whose signal increases and whose synovia becomes inflamed. The latter pattern is always distinguished from that of the autograft, whose signal intensity seems not to change in time. In conclusion, MR proved an accurate and non-invasive technique to image this kind of postoperative knee, since metallic artifacts do not reach the joint space.