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Detection of a thyroid nodule, either incidental or as a result of related symptomatology, is an extremely common event, often inducing considerable uncertainty regarding the requirement for and best means of further investigation. Whereas tissue sampling represents the sole means of true characterization of these lesions, a number of imaging characteristics have been suggested as potential indicators of the presence of malignancy. The potential value of time-resolved MR angiography, whereby a minimal dose of i.v. contrast agent is dynamically depicted during the first pass of the bolus through the various compartments of circulation, has recently been realized, particularly so with regard to supraaortic angiography. However, it is not uncommon during such temporal imaging to identify focal hyperenhancing thyroid nodules, the significance of which has not previously been described in the literature. We describe the frequency of occurrence and potential significance of this finding, using pathologic correlation where available.The prevalence of malignancy in incidentally detected focal hyperenhancing thyroid parenchymal nodules during time-resolved MR angiography is significant, representing 8.3% (1/12) of patients for whom cytologic correlation was available. Further investigation is certainly warranted when encountering such a lesion in clinical practice, particularly because it appears as though time-resolved MR angiography is of no value in the pathologic discrimination of such incidentally identified lesions.

The purpose of our study was to evaluate the use of preoperative MR angiography of the lower extremities at 3 T in candidates for fibular free flap harvesting, identifying atherosclerotic occlusive disease and congenital anomalies in this population. Our intention was to document the influence of the imaging findings on the surgical approach used.Twenty-nine consecutive adult patients with facial abnormalities necessitating mandibular resection with subsequent osteocutaneous mandibular reconstruction who underwent preoperative MR angiography at 3 T were retrospectively reviewed. Images were evaluated by two observers with regard to image quality and visualization of arterial segments; severity of stenosis; and presence of noise, artifact, or venous contamination. The popliteal artery branching pattern present was also classified. The facial and reconstructive surgeon involved indicated whether the MR angiographic appearances influenced the decision regarding the side or location from which the flap was harvested or the flap design.Arterial segments were visualized with good or excellent image quality in 722 of 725 segments for observer 1 and 721 segments for observer 2. The kappa coefficient indicated good interobserver agreement (kappa = 0.78) with regard to quality of arterial segment depiction and scoring of stenoocclusive disease (kappa = 0.64). No segments had venous contamination, noise, or artifact of a degree sufficient to compromise diagnostic interpretation. Imaging influenced the surgical approach in 16 (55.2%) of 29 patients.Trifurcation vessel imaging should be a prerequisite to fibular free flap harvesting. High-spatial-resolution MR angiography at 3 T represents a desirable alternative to other invasive or cross-sectional imaging techniques in this regard.

A number of clinical situations exist in which high-resolution depiction of the external carotid artery system is required, a task not previously addressed by MR angiography. The purpose of this study was to evaluate the extent to which high-spatial-resolution MR angiography at 3 T can be used to map the normal external carotid artery system.Twenty-three consenting adult patients were prospectively evaluated. Images acquired were evaluated by two independent observers, and each branch vessel was scored with regard to image quality, presence and grade of stenoses, and artifacts. Interobserver agreement regarding image quality and the presence and degree of stenosis was tested using the kappa coefficient. Differences in quality ratings between the two observers were assessed using the paired Student's t test.Of 828 vessels analyzed, 92.63% were designated of diagnostic quality with no significant difference between the observers' image quality scores (p = 0.63). Good agreement was determined regarding image quality achieved (kappa = 0.716). All examinations were free of artifact sufficient to interfere with confident interpretation. Excellent correlation was seen with regard to stenosis detection and grading (kappa = 0.857). Of the external carotid artery systems assessed, 82.6% showed conventional anatomic vascular branching.High-spatial-resolution, 3D contrast-enhanced MR angiography at 3 T using sagittal source data acquisition and an advanced acceleration factor of 6 allows high-quality (92.63% of arterial segments) visualization of the external carotid artery system, with complete head and neck vascular coverage.