Double-subtraction maximum intensity projection MR angiography for detecting the artery of Adamkiewicz and differentiating it from the drainage vein

Comparison of slow-infusion magnetic resonance angiography with sequential k-space filling and computed tomography angiography to detect the Adamkiewicz artery

OBJECTIVE

Radiographic detection of the Adamkiewicz artery (AKA) before aortic surgery helps to avoid spinal cord ischemia (SCI). We applied magnetic resonance angiography (MRA) using gadolinium enhancement (Gd-MRA) by means of the slow-infusion method with sequential k-space filling and compared AKA detectability with that of computed tomography angiography (CTA).

METHODS

A total of 63 patients with thoracic or thoracoabdominal aortic disease (30 with aortic dissection [AD] and 33 with aortic aneurysm) who underwent both CTA and Gd-MRA to detect AKA were evaluated. The detectability of the AKA using Gd-MRA and CTA were compared among all patients and subgroups based on anatomical features.

RESULTS

The detection rates of the AKAs using Gd-MRA and CTA were higher in all 63 patients (92.1% vs. 71.4%, p = 0.003). In AD cases, the detection rates using Gd-MRA and CTA were higher in all 30 patients (93.3% vs. 66.7%, p = 0.01) as well as in seven patients whose AKA originated from false lumens (100% vs. 0%). In aneurysm cases, the detection rates using Gd-MRA and CTA were higher in 22 patients whose AKA originated from the non-aneurysmal parts (100% vs. 81.8%, p = 0.03). In clinical, SCI was observed in 1.8% of cases after open or endovascular repair.

CONCLUSION

Despite the longer examination time and more complicated imaging techniques compared to those of CTA, the high spatial resolution of slow-infusion MRA may be preferable for detecting AKA before performing various thoracic and thoracoabdominal aortic surgeries.

Artery of Adamkiewicz: a meta-analysis of anatomical characteristics

PURPOSE

The artery of Adamkiewicz (AKA) provides the major blood supply to the anterior thoracolumbar spinal cord and iatrogenic injury or inadequate reconstruction of this vessel during vascular and endovascular surgery can result in postoperative neurological deficit due to spinal cord ischemia. The aim of this study was to provide comprehensive data on the prevalence and anatomical characteristics of the AKA.

METHODS

An extensive search was conducted through the major electronic databases to identify eligible articles. Data extracted included study type, prevalence of the AKA, gender, number of AKA per patient, laterality, origin based on vertebral level, side of origin, morphometric data, and ethnicity subgroups.

RESULTS

A total of 60 studies (n = 5437 subjects) were included in the meta-analysis. Our main findings revealed that the AKA was present in 84.6% of the population, and patients most frequently had a single AKA (87.4%) on the left side (76.6%) originating between T8 and L1 (89%).

CONCLUSION

As an AKA is present in the majority of the population, caution should be taken during vascular and endovascular surgical procedures to avoid injury or ensure proper reconstruction. All surgeons operating in the thoracolumbar spinal cord should have a thorough understanding of the anatomical characteristics and surgical implications of an AKA.

Novel application of 3-dimensional rotational C-arm conebeam computed tomography angiography for metastatic hypervascular tumor mass in the spine

STUDY DESIGN

This is a case report.

OBJECTIVE

To report a 3-dimensional (3D) rotational C-arm conebeam computed tomography (CT) (DynaCT) angiography generating computed tomographic data concurrently with spinal angiographic datasets. This technology allowed 3D modeling of the anterior spinal arterial supply in juxtaposition to a hypervascular tumor mass, thus affording unprecedented guidance in presurgical planning.

SUMMARY OF BACKGROUND DATA

An enhanced demonstration of spatial relationships between the vascular elements and their adjacent soft-tissue structures is needed to visualize the minute anterior spinal artery optimally.

METHODS

A 76-year-old male with a history of renal cell carcinoma metastasis to the T6 vertebra 1 year prior, presented with worsening myelopathy caused by severe spinal cord compression at T6 level, and a plan for surgical decompression was established. Because of the hypervascular nature of this renal cell carcinoma metastasis, preoperative embolization was requested to minimize blood loss during the operation. A digital subtraction angiogram identified the major arterial contribution to the tumor to also supply the radiculomedullary branch to the anterior spinal artery. To further characterize this blood supply, a rotational DynaCT angiography was performed.

RESULTS

The rotationally acquired data were processed generating volumetric CT datasets demonstrating the 3D relationships of the anterior spinal artery, the blood supply to the tumor and the adjacent soft-tissue and bony structures. A shared blood supply to both the tumor mass and the anterior spinal artery from the left T6 segmental artery was confirmed. The dual nature of this blood supply presented increased risk of ischemic spinal cord injury by possible nontarget embolization. Therefore, the embolization was deferred.

CONCLUSION

The DynaCT angiography precisely characterized the complex blood supply of a hypervascular vertebral tumor mass in relation to a shared arterial supply to the thoracic spinal cord. The optimal visualization properly aided presurgical planning.

LEVEL OF EVIDENCE

N/A.

Neurologic complications of aortic diseases and aortic surgery

Aortic disease processes have a wide range of clinical manifestations. The inflammatory disease process of Takayasu's arteritis differs dramatically from the visceral ischemia of aortic dissection. The catastrophic event of aortic rupture tends to overshadow life-altering events such as stroke and paraplegia. However, these neurologic manifestations of aortic diseases have dramatic effects that extend beyond the individual patient to include both social and financial ramifications. This chapter focuses on the major aortic disease processes and how they can initiate, both directly and indirectly, adverse neurologic events. The chapter concludes with a brief discussion of aortic surgery, how interventions on the aorta can cause neurologic complications, and techniques to avoid these feared adverse neurologic outcomes.

MR angiography for detecting the artery of Adamkiewicz and its branching level from the aorta

PURPOSE

We evaluated the efficacy of magnetic resonance angiography (MRA) for detecting the artery of Adamkiewicz (AKA) and the vertebral level of its feeding arteries branching from the aorta.

MATERIALS AND METHODS

Eighty-two patients (67 men, 15 women; aged 34 to 86 years, mean age 68.6 years) with thoracic descending and thoracoabdominal aortic lesions (aneurysm in 55, dissection in 25, coarctation in 2) underwent MRA to detect AKA. MRA was performed using 6-phase, dynamic-enhanced, 3-dimensional, fast spoiled gradient recalled acquisition in steady state (GRASS) on a 1.5-tesla (T) system, with double-dose bolus contrast injection. The vertebral levels of AKA branching and the AKA feeder artery branching from the aorta were determined.

RESULTS

The AKA was detected in 67 patients (81.7%). Branching of AKA occurred at levels T7 to T12 on the left side (n=52) and on the right (n=15). Vascular continuity from the aorta to the anterior spinal artery was demonstrated in 55 patients (67.1%). Comparing the vertebral level of arterial branching from the aorta to that of the AKA at the intervertebral foramen, the AKA branched at the same vertebral level in 44 patients (80.0%), one vertebral level above/below in 10 (18.2%), and 2 vertebral levels above in one (1.8%).

CONCLUSION

MRA can be useful in the preoperative work-up of patients with thoracoabdominal aortic lesions to localize AKA and the segmental trajectories of vessels supplying blood to the AKA.

Comparison of gadobenate dimeglumine and gadodiamide in the evaluation of spinal vascular anatomy with MR angiography

BACKGROUND AND PURPOSE

Spinal MRA has been increasingly used to evaluate non-invasively the spinal cord vasculature. Our aim was to prospectively compare gadobenate dimeglumine with gadodiamide in the assessment of the normal spinal cord vasculature by using contrast-enhanced MRA, with the hypothesis that high T1 relaxivity gadolinium compounds may improve visualization of the intradural vessels.

MATERIALS AND METHODS

Twenty subjects underwent 2 temporally separated contrast-enhanced spinal MRAs with gadobenate dimeglumine and gadodiamide (0.2 mmol/kg). Two blinded observers rated postprocessed images on the following qualitative parameters: background homogeneity, sharpness, vascular continuity, and contrast enhancement. Delineation of the ASA, AKA, hairpin configuration of the ASA-AKA connection, and visualized ASA length were recorded. Each observer indicated which of the 2 matched studies he or she thought was of the best overall diagnostic quality.

RESULTS

According to both observers gadobenate dimeglumine was superior to gadodiamide in the representation of vascular continuity and contrast (P value < .05). Background homogeneity was not significantly different between the studies. One observer favored gadobenate dimeglumine over gadodiamide in the demonstration of vascular sharpness, while the second observer did not find any significant difference between contrast agents. There was no significant difference between contrast agents in the visualization of the ASA, AKA, hairpin-shaped ASA-AKA connection, and visualized length of the ASA. The overall quality of the gadobenate dimeglumine-enhanced MRA was deemed superior in 15 and 16 cases, respectively, by the 2 observers.

CONCLUSIONS

Improved image quality and vascular contrast enhancement of spinal MRA at 1.5T is achieved with high T1 relaxivity gadolinium contrast agents compared with conventional agents at equivalent doses.

Advances in imaging of the spinal cord vascular supply and its relationship with paraplegia after aortic interventions. A review

INTRODUCTION

Preoperative knowledge of the spinal cord (SC) vasculature could be useful for stratifying and decreasing the risk of perioperative paraplegia after thoracic and thoraco-abdominal aortic surgery. Recent advances in magnetic resonance (MR) and computed tomography (CT) angiography and post-processing techniques have improved this knowledge.

METHODS

A search of MEDLINE/Pubmed and SCOPUS databases identified 1414 pertinent abstracts; 123 full-length manuscripts were screened to identify relevant studies with acceptable design and patient numbers. Forty-three were selected.

RESULTS

SC circulation was studied in 1196 patients to detect the great radicular artery: 522 by MR-angiography and 674 by CT angiography. Detection rates were 67-100% (mean 80.8%) with MR-angiography being 18-100% (mean 72%) with CT angiography. The side and level of the great radicular artery were consistent between the methods. Several authors tried to use the imaging results to guide clinical management.

CONCLUSIONS

Non-invasive imaging of the SC blood supply allows preoperative definition of the vasculature in many, but not all, cases. The impact of these findings on clinical management is potentially beneficial but still uncertain. Further improvements in image acquisition and post-processing techniques are needed. Future studies need to be large enough to compensate for inter-individual variability in SC vasculature in health and disease; however, even a partial reduction of paraplegia rate offers a formidable motivation for further research in this area.

Albert Wojciech Adamkiewicz (1850-1921): unsung hero behind the eponymic artery

The artery of Adamkiewicz is an important radiculomedullary artery supplying the spinal cord, especially the lumbar enlargement. Anatomical knowledge of this artery is important for avoiding serious neurological complications during surgery performed in this region--for neurosurgeons and interventional radiologists treating intramedullary tumors and spinal arteriovenous malformations, traumatologists performing spinal fusions, thoracic surgeons treating aortic aneurysms, and urologists and pediatric surgeons conducting retroperitoneal dissections. However, the biography of the talented Polish pathologist Albert Adamkiewicz, after whom the landmark artery is named, has not been described adequately in the existing neurosurgical literature. The authors bring to light the historical perspective of the eponymic artery and provide a recapitulation of other significant contributions made by Adamkiewicz, mostly involving the nervous system. His research papers on the histology of neuronal tissues and neurodegenerative diseases had high scientific merit, but the discovery of the anticancer antitoxin "cancroin" and his postulation of a cancer-causing parasite he named "Coccidium sarcolytus" met with harsh criticism and eventually led to his ill fame. The biography is supplemented with a brief overview of the important surgical implications of the artery of Adamkiewicz.

Advances in spinal cord MR angiography

Novel developments in MR angiography are reviewed that enable non-invasive clinical imaging of normal and abnormal vessels of the spinal cord. Current fast contrast-enhanced MR techniques are able 1) to visualize vessels supplying or draining the spinal cord and 2) to differentiate spinal cord arteries from veins. The localization of the Adamkiewicz artery, the largest artery supplying the thoracolumbar spinal cord, has become possible in a reproducible and reliable manner. Knowledge of the anatomic location of this artery and its arterial supplier may be of benefit in the work-up for aortic aneurysm surgery to reduce incidences of ischemic injury. Spinal cord MR angiography is ready to become a diagnostic tool that can compete with catheter angiography for detecting and localizing arterial feeders of vascular lesions and is strongly advised for use prior to invasive catheter angiography. Successful clinical application strongly relies on in depth knowledge of the complex spinal cord vasculature and skills in image postprocessing.