Time-Resolved and Bolus-Chase MR Angiography of the Leg: Branching Pattern Analysis and Identification of Septocutaneous Perforators

Abstract

OBJECTIVE The goal of this study was to compare time-resolved MR angiography (MRA) and bolus-chase MRA in the identification of peroneal artery septocutaneous perforators and for classification of the branching pattern of the arterial tree in the leg in a cohort of candidates for fibular free flap transfer operations. MATERIALS AND METHODS Retrospective analysis was performed on imaging data from 53 legs of 27 patients (age range, 27–88 years) who underwent time-resolved MRA (FLASH; TR/TE, 2.5/1.0; flip angle, 22°; voxel dimensions, 1.54 × 1.25 × 1.5 mm; acquisition time, 2.27 s/frame) and bolus-chase MRA (FLASH; 3.2/1.2; flip angle, 25°; voxel dimensions, 0.94 × 0.89 × 1 mm) at 3 T with gadobenate dimeglumine administered at 0.05 and 0.10 mmol/kg, respectively. The branching pattern was analyzed; the total number of septocutaneous perforators for each leg was calculated from the time-resolved and bolus-chase MRA data; and the results were combined. The total and average number of septocutaneous perforators per leg and the frequency of various branching patterns were calculated. The techniques were compared in terms of branching pattern and number of visible septocutaneous perforators. RESULTS A total of 84 septocutaneous perforators (1.58 ± 1.05 [SD] per leg) were identified. Pattern 1A was found in 42 legs; 1B, two legs; 2A, one leg; 2B, one; 3A, four; 3B, one; and 3D, two legs. Classification with time-resolved MRA was successful for 53 legs and with bolus-chase MRA for 51 legs (Z = 0.713, p = 0.24, one-tailed, not significant). Twenty-two septocutaneous perforators were identified with time-resolved MRA and 82 with bolus-chase MRA. CONCLUSION MRA of the leg can be used to investigate the branching pattern and identify septocutaneous perforators in a single step. With the imaging parameters and contrast dose used in this study, septocutaneous perforators can be better identified with bolus-chase MRA, although this result may be partially related to the higher gadolinium dose used in this technique.

Anatomical variants of lower limb vasculature and implications for free fibula flap: Systematic review and critical analysis

“…None of the cadaveric studies reported hypoplasia or aplasia of the PR, in any of the 791 limbs dissected. On the contrary, the PR was reported to be angiographically hypoplastic (type IV‐A variant) in eight limbs, and aplastic (type IV‐B variant) in four limbs, with overall incidence of 0.14% and 0.07%, respectively (Fig. ).…”

“…In the other two subtypes, the PR shares the blood supply to the foot along with the remaining tibial vessel, and usually has larger diameter suggesting a relative dominance of the vessel . Clinical examination alone may fail to detect these variations, and unlike the Allen's test in the forearm, dominant variant vessels of lower limb cannot be clinically detected before surgery . Harvesting the dPR may potentially place a risk on 10% of patients with anatomical variants.…”

A Systematic Review and Pooled Analysis of Peroneal Artery Perforators for Fibula Osteocutaneous and Perforator Flaps

“…As such, Sandhu et al investigated the utility of time-resolved magnetic resonance angiography and bolus-chase magnetic resonance angiography in clinical candidates for a free fibula osteocutaneous flap. 5 A total of 53 legs from 27 patients were retrospectively reviewed, with the greatest density of peroneal septocutaneous perforators (82.2 percent) along the distal two-thirds of the fibula.…”

“…5 Similarly, two reports did not differentiate their data based on perforator branch types, so these reports were excluded from the musculocutaneous and septocutaneous subgroup calculations. 6,7 Table 1 lists the demographic and study characteristics of the final data group.…”

Time-Resolved MR Angiography of the Legs at 3 T Using a Low Dose of Gadolinium: Initial Experience and Contrast Dynamics

“…In patients who underwent the examination for planning a fibula free-flap transfer operation, the lower resolution examination still allowed proper evaluation of the lower extremity vascular branching patterns and lesion localization, although perforator localization is more accurate with a higher-resolution examination. Repeat examinations were not required in any patient [24]. …”