Timothy J. Phillips

Preoperative imaging for DIEA perforator flaps: a comparative study of computed tomographic angiography and Doppler ultrasound.

BACKGROUND Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA. METHODS Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team. RESULTS Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography. CONCLUSION Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.Background: Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA. Methods: Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team. Results: Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography. Conclusion: Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.

Safety of the Pipeline Embolization Device in Treatment of Posterior Circulation Aneurysms

BACKGROUND AND PURPOSE: The published results of treating internal carotid artery aneurysms with the PED do not necessarily apply to its use in the posterior circulation because disabling brain stem infarcts can be caused by occlusion of a single perforator. In this multicenter study, we assessed the safety of PED placement in the posterior circulation. MATERIALS AND METHODS: A prospective case registry was maintained of all posterior circulation aneurysms treated with PEDs at 3 Australian neurointerventional centers during a 27-month period. The objective was to assess the complications and aneurysm occlusion rates associated with posterior circulation PEDs. RESULTS: Thirty-two posterior circulation aneurysms were treated in 32 patients. No deaths or poor neurologic outcomes occurred. Perforator territory infarctions occurred in 3 (14%) of the 21 patients with basilar artery aneurysms, and in all 3, a single PED was used. Two asymptomatic intracranial hematomas were recorded. No aneurysm rupture or PED thrombosis was encountered. The overall rate of permanent neurologic complications was 9.4% (3/32); all 3 patients had very mild residual symptoms and a good clinical outcome. Aneurysm occlusion was demonstrated in 85% of patients with >6 months of follow-up and 96% of patients with >1 year of follow-up. CONCLUSIONS: The PED is effective in the treatment of posterior circulation aneurysms that are otherwise difficult or impossible to treat with standard endovascular or surgical techniques, and its safety is similar to that of stent-assisted coiling techniques. A higher clinical perforator infarction rate may be associated with basilar artery PEDs relative to the internal carotid artery.

Abdominal Wall CT Angiography: A Detailed Account of a Newly Established Preoperative Imaging Technique

Institutional review board approval was obtained for this study, and all patients gave written informed consent. Autologous surgical breast reconstruction with use of abdominal wall donor flaps based on the deep inferior epigastric artery (DIEA) and one or more of its anterior musculocutaneous perforating branches (DIEA perforator flap) is being used with increasing frequency instead of breast reconstruction with use of traditional transverse rectus abdominus musculocutaneous and modified muscle-sparing flaps. Preoperative mapping of the DIEA perforators with abdominal wall computed tomographic (CT) angiography may improve patient care by providing the surgeon with additional information that will lead to optimization of the surgical technique, shorter procedure time, and reduction in the frequency of surgical complications. The branching patterns of the DIEA, the segmental anatomy of the anterior adipocutaneous perforating branches of the DIEA, and the importance of these features in pre- and intraoperative surgical planning necessitate a different approach to abdominal wall CT angiography than that used with other abdominal CT angiographic techniques. In abdominal wall CT angiography, the common femoral artery is used as the bolus trigger, CT scanning is performed in the caudocranial direction, the automatic exposure control feature is disabled, a scaled grid overlay tool is used to present information to the surgeons, and radiation dose is minimized (average dose, 6 mSv). The anatomic accuracy of abdominal wall CT angiography has been investigated in cadaveric and surgical studies, with sensitivity of 96%-100% and specificity of 95%-100%. This detailed description will allow other radiologists and surgeons interested in free DIEP flap surgery to incorporate this useful tool into their practice.

Does Treatment of Ruptured Intracranial Aneurysms Within 24 Hours Improve Clinical Outcome

Background and Purpose— The purpose of this study was to analyze whether treating ruptured intracranial aneurysms within 24 hours of subarachnoid hemorrhage improves clinical outcome. Methods— An 11-year database of consecutive ruptured intracranial aneurysms treated with endovascular coiling or craniotomy and clipping was analyzed. Outcome was measured by the modified Rankin Scale at 6 months. Our policy is to treat all cases within 24 hours of subarachnoid hemorrhage. Treatment delays are due to nonclinical logistical factors. Results— Two hundred thirty cases were coiled or clipped within 24 hours of subarachnoid hemorrhage and 229 at >24 hours. No difference in age, gender, smoking, family history of subarachnoid hemorrhage, aneurysm size, or aneurysm location was found between the groups. Poor World Federation of Neurological Surgeons clinical grade patients were overrepresented in the ultra-early group. Increasing age and higher World Federation of Neurological Surgeons clinical grade were predictors of poor outcome. Eight point zero percent of cases treated within 24 hours of subarachnoid hemorrhage (ultra-early) were dependent or dead at 6 months compared with 14.4% of those treated at >24 hours (delayed), a 44.0% relative risk reduction and a 6.4% absolute risk reduction (&khgr;2, P=0.044). A total of 3.5% of cases coiled within 24 hours were dependent or dead at 6 months compared with 12.5% of cases coiled at 1 to 3 days, an 82% relative risk reduction and a 10.2% absolute risk reduction (&khgr;2, P=0.040). These groups did not differ in age, World Federation of Neurological Surgeons clinical grade, aneurysm size, or aneurysm location. Conclusions— Treatment of ruptured aneurysms within 24 hours is associated with improved clinical outcomes compared with treatment at >24 hours. The benefit is more pronounced for coiling than clipping.

The accuracy of computed tomographic angiography for mapping the perforators of the deep inferior epigastric artery: a blinded, prospective cohort study.

Background: The deep inferior epigastric artery perforator flap is increasingly used for autologous breast reconstruction, with low donor-site morbidity cited as a major advantage of this operation. Preoperative imaging of the donor-site vasculature is frequently used as a further means of improving operative outcome. Computed tomographic angiography has been increasingly described as a preferred imaging modality; however, its formal evaluation has not been described in a clinical setting. Methods: A prospective, single-blind, cohort study was undertaken on 60 consecutive patients for whom deep inferior epigastric artery perforator flap surgery had been planned. Patients who did not undergo the procedure during the study period were excluded, with 42 patients ultimately included in the study. All computed tomographic angiography scans were obtained at a single institution. Perforators were mapped both on angiography and intraoperatively using a grid of 4-mm squares centered on the umbilicus. Only perforators larger than 1 mm were included in the study. All imaging findings were recorded by a single operator, and all intraoperative findings were recorded by the operating surgeon. Results: Computed tomographic angiography identified 280 major perforators in 42 patients. It was highly accurate, demonstrating 279 perforators recorded accurately, with one false-positive and one false-negative. Its sensitivity for mapping perforators was thus 99.6 percent, with a positive predictive value of 99.6 percent. Conclusions: Computed tomographic angiography is highly accurate in identifying and mapping the perforators of the deep inferior epigastric artery. Its accuracy is superior to that of the previous modalities used in this role and suggests the usefulness of this technique before deep inferior epigastric artery perforator flap surgery for breast reconstruction.

Establishing the case for CT angiography in the preoperative imaging of abdominal wall perforators

Preoperative imaging of the donor site vasculature for deep inferior epigastric artery (DIEA) perforator flaps and other abdominal wall reconstructive flaps has become more commonplace. Abdominal wall computed tomography angiography (CTA) has been described as the most accurate and reproducible modality available for demonstrating the location, size, and course of individual perforators. We drew on our experience of 75 consecutive patients planned for DIEA‐based flap surgery undertaking CTA at a single institution. Seven of these cases have been reported to highlight the utility of CTA for preoperative planning, emphasizing the unique information supplied by CTA that may influence operative outcome. Among all cases that underwent preoperative imaging with CTA, there was 100% flap survival, with no partial or complete flap necrosis. We found that in three of the cases described, the choice of operation was necessarily selected based on CTA findings (DIEA perforator flap, transverse rectus abdominis myocutaneous flap, and superficial superior epigastric artery flap). In addition, three cases demonstrate that CTA findings may dictate the decision to operate at all, and one case demonstrates the utility of CTA for evaluating the entire abdominal contents for comorbid conditions. Our experience with CTA for abdominal wall perforator mapping has been highly beneficial. CTA may guide operative technique and improve perforator selection in uncomplicated cases, and in difficult cases it can guide the most appropriate operation or indeed if an operation is appropriate at all. This is particularly the case in the setting of comorbidities or previous abdominal surgery.

Long-Term Follow-Up Results following Elective Treatment of Unruptured Intracranial Aneurysms with the Pipeline Embolization Device

BACKGROUND AND PURPOSE: Numerous reports of treatment of wide-neck aneurysms by flow diverters have been published; however, long-term outcomes remain uncertain. This article reports the imaging results of unruptured aneurysms treated electively with the Pipeline Embolization Device for up to 56 months and clinical results for up to 61 months. MATERIALS AND METHODS: One hundred nineteen aneurysms in 98 patients from 3 centers admitted between August 2009 and June 2011 were followed at 6-month, 1-year, and 2+-year postprocedural timeframes. Analyses on the effects of incorporated vessels, previous stent placement, aneurysm size, and morphology on aneurysm occlusion were performed. RESULTS: The 1- and 2+-year imaging follow-ups were performed, on average, 13 and 28 months postprocedure. At 2+-year follow-up, clinical data were 100% complete and imaging data were complete for 103/116 aneurysms (88.8%) with a 93.2% occlusion rate. From 0 to 6 months, TIA, minor stroke, and major stroke rates were 4.2%, 3.4%, and 0.8% respectively. After 6 months, 1 patient had a TIA of uncertain cause, with an overall Pipeline Embolization Device–related mortality rate of 0.8%. An incorporated vessel was significant for a delay in occlusion (P = .009) and nonocclusion at 6 months and 1 year, with a delayed mean time of occlusion from 9.1 months (95% CI, 7.1–11.1 months) to 16.7 months (95% CI, 11.4–22.0 months). Other factors were nonsignificant. CONCLUSIONS: The Pipeline Embolization Device demonstrates continued very high closure rates at 2+ years, with few delayed clinical adverse sequelae. The presence of an incorporated vessel in the wall of the aneurysm causes a delay in occlusion that approaches sidewall closure rates by 2 years.

Developments in perforator imaging for the anterolateral thigh flap: CT angiography and CT‐guided stereotaxy

Introduction: The anterolateral thigh flap is an increasingly popular reconstructive option despite uncertainty in its perforator anatomy. Perforators are not always present, vary in size and intramuscular course, and have variable cutaneous courses and supply. As such, preoperative imaging has become favored. Methods: The current study describes the preliminary use of two new modalities for preoperative imaging: computed tomography (CT) Angiography and CT‐guided stereotaxy. These have been utilized in the preoperative imaging of two patients undergoing ALT flap reconstruction. Each patient underwent each of these techniques combined with Doppler ultrasound, the previous standard modality. The size, location, and course of perforators were explored and compared with operative findings. Results: Both techniques are technically feasible, highly accurate, and provide more information to the surgeon than ultrasound. Conclusion: CT Angiography and CT‐guided stereotaxy are useful adjuncts to Doppler ultrasound for imaging perforators prior to ALT flaps. A larger study is suggested to quantify the accuracy of these techniques.

The Accuracy of Computed Tomographic Angiography for Mapping the Perforators of the Diea: A Cadaveric Study

Background: The deep inferior epigastric artery (DIEA) perforator flap is increasingly used for breast reconstruction, with preoperative imaging sought as a means of improving operative outcome. Computed tomographic angiography has been recently described as the preferred imaging modality; however, formal evaluation of computed tomographic angiography has not been described. A cadaveric study was undertaken to evaluate the accuracy of computed tomographic angiography for perforator mapping. Methods: Ten cadaveric hemiabdominal walls from five fresh cadavers underwent contrast injection of each DIEA and subsequent computed tomographic scanning, with each DIEA and all perforating branches documented. Dissection was then performed, with the recording of the course of the DIEA and the course of all perforators in each specimen. The concordance of computed tomographic angiography with dissection findings was evaluated. Results: Cadaveric computed tomographic angiography identified 154 perforators in 10 hemiabdominal walls. Computed tomographic angiography was highly accurate, with eight false-positives and six false-negatives on cadaveric computed tomographic angiography, establishing an overall sensitivity of 96 percent and a positive predictive value of 95 percent for mapping perforators. For perforators greater than 1 mm in diameter, the sensitivity was 100 percent and the positive predictive value was 100 percent. Conclusions: Computed tomographic angiography is a highly accurate tool for identifying the perforators of the DIEA before DIEA perforator flaps for breast reconstruction. Preoperative identification of these vessels can aid planning for the preferred hemiabdomen for dissection, and may save operative time, angst, and potentially complications.

Endovascular treatment of complex aneurysms at the vertebrobasilar junction with flow-diverting stents: initial experience.

BACKGROUND Large or giant complex vertebrobasilar junction aneurysms have a dismal natural history and are often challenging to treat with standard endovascular or neurosurgical techniques. OBJECTIVE To report initial experience with endovascular treatment of these aneurysms using flow-diverting stents (FDS). METHODS Ten patients with FDS treatment of complex vertebrobasilar junction aneurysms were collected from 4 large cerebrovascular centers. Clinical/angiographic presentation and outcome were retrospectively analyzed. RESULTS Of 10 aneurysms, 7 presented with brainstem compression, 2 with ischemia, and 1 with subarachnoid hemorrhage, and 3 were recurrent after stent-assisted treatments. Eight were giant. Morphology was fusiform in 5, fusiform dissecting in 1, and multilobulated saccular in 4. Six were partially thrombosed. In addition to FDS (mean number of devices, 3.9; range, 1-9), contralateral vertebral artery sacrifice and adjunctive coiling were performed in 9 and 5 of the 10 patients, respectively. At follow-up, 5 of 10 were completely occluded, 4 showed minimal residual filling, and 1 was retreated with an additional FDS. Postinterventionally, worsening mass effect and ischemic complications were seen in 2 and 4 of 10, respectively. Clinical outcome was good in 6 (modified Rankin Scale score, 0-2). Four fatalities were related to sequelae of subarachnoid hemorrhage, late FDS thrombosis, progressive mass effect, and delayed intracranial hemorrhage. CONCLUSION FDS may be used to treat complex vertebrobasilar junction aneurysms with overall good angiographic outcome. A combined reconstructive/deconstructive approach appears useful to avoid endoleaks. FDS strategies, like other endovascular and neurosurgical approaches to these lesions, are associated with significant risk and therefore should be reserved for those cases in which alternative approaches either are deemed unsafe or are likely to be ineffective. ABBREVIATIONS FDS, flow-diverting stentPED, Pipeline Embolization DeviceSAH, subarachnoid hemorrhageVA, vertebral arteryVBJ, vertebrobasilar junction.