author, Stefan O. Schoenberg, MD
 Image A |
 Image B |
 Image C |
Clinical History:
This 63-year-old woman presented for a routine check up with a known peripheral arterial occlusive disease (PAOD) and medical history of diabetes mellitus type I. The patient remains relatively stable with a possible walking distance of 250m before showing symptoms of an intermittent claudication. Therefore the PAOD is classified as Fontaine stage IIa.
Diagnosis:
Peripheral arterial occlusive disease, Fontaine stage II.
MR Technique:
The exam of the lower extremities was acquired on a 32-channel 3T scanner (Siemens MAGNETOM Tim Trio) using a dedicated peripheral angiography matrix coil with 36 independent coil elements. During a single MR-exam, patients underwent non-enhanced (NE)-MRA of the calf station as well as contrast-enhanced, continuous table movement (CTM)-MRA and time-resolved TWIST-MRA. Initially NE-MRA was performed using a coronal, non-enhanced, ECG-gated, turbo-spin echo sequence (“nativeSPACE”, TR=2R-R intervals, TE=34ms, voxel size 1.4x1.4x1.3mm3) presented in image A. This sequence acquires systolic and diastolic images, subtracts the data set of the systole and the diastole, with the resulting image only demonstrating the arterial system. For the determination of the systolic and diastolic ECG trigger delay (TD) for the NE-MRA an inversion recovery 2D ECG-gated half-Fourier fast spin echo sequence with TD intervals of 50ms ranging from 0ms to 900ms was acquired. The resulting systolic and diastolic delay times were established using the system’s MeanCurve tool.For the contrast-enhanced MRA techniques, a combined sequence protocol, consisting of CTM-MRA (image B) and TWIST-MRA (image C) with a split single dose of gadobutrol was acquired. A total of 0.1 mmol/kg BW gadobutrol was injected at 1.5 mL/s (70% for CTM-MRA and 30% for TWIST-MRA). For the CTM-MRA a3D FLASH sequence was used (TR=2.4ms/ TE=1.0ms/ 1.2mm isotropic resolution). Beforehand for calculation of the correct individual circulation time for the CTM-MRA, a test bolus was performed with 1mL gadobutrol. The administration was followed by a saline chaser of 30mL. The TWIST-MRA (TR=2.8ms/ TE=1.1ms)/ 1.1mm isotropic resolution) of the calf station was started 2 minutes after the CTM-MRA. A complete 3D data set was acquired every 5.5s.
Imaging Findings:
In the coronal MIP-view the three different MR-angiography techniques are presented (A.NE-MRA, B.CTM-MRA, C.TWIST-MRA). In this examination, the three different techniques show equal high image quality. The vascularization of the lower leg is mainly maintained on the left side by the anterior tibial artery and the peroneal artery. The posterior tibial artery is proximal occluded. On the other side a similar situation can be found, whereby the posterior tibial artery shows only in the proximal part sequential moderate lumen reductions.
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