MDCT angiography of the spinal vasculature and the artery of Adamkiewicz

Variceal and Nonvariceal Upper Gastrointestinal Bleeding Refractory to Endoscopic Management: Indications and Role of Interventional Radiology

For over 60 years, diagnostic and interventional radiology have been heavily involved in the evaluation and treatment of patients presenting with gastrointestinal bleeding. For patients who present with upper GI bleeding and have a contraindication to endoscopy or have an unsuccessful attempt at endoscopy for identifying or controlling the bleeding, interventional radiology is often consulted for evaluation and consideration of catheter-based intervention.

Unraveling the enigma of Adamkiewicz: exploring the prevalence, anatomical variability, and clinical impact in spinal embolization procedures for bone metastases

BACKGROUND

The artery of Adamkiewicz (AKA) is vital for spinal cord blood supply. Its role in embolization procedures for bone metastases can cause serious complications. We explored its prevalence, anatomical variation, and effect on spinal embolization using N-butyl cyanoacrylate (NBCA) in patients with bone metastases.

PURPOSE

To understand the impact and variability of AKA in spinal embolizations in cases of bone metastases to reduce complications and improve patient outcomes.

MATERIAL AND METHODS

We examined data from 454 patients who underwent spinal embolization with NBCA between 2009 and 2018. The presence, anastomoses, and tumor features of AKA were assessed via pre-procedure imaging and angiography. Complications were classified per the CIRSE Classification System.

RESULTS

AKA was found in 22.8% of patients, predominantly left-sided and originating from T8 to L1. Direct and indirect anastomoses were present in 66.6% and 33.4% of patients, respectively. Extra-compartmental invasion was linked with direct anastomosis (P = 0.004). High-grade complications were rare but included one instance of bilateral lower limb paralysis. Partial embolization was necessary in 22.8% of cases due to AKA.

CONCLUSION

The study underscores the need for rigorous preoperative evaluation of AKA origin and anastomoses in patients undergoing spinal embolization for bone metastases. Given the significant presence of AKA and related anastomoses, especially with renal extra-compartmental tumors, caution is advised to reduce complications and optimize patient outcomes. Further research is required for best practice guidelines involving bone metastases and AKA.

What the Musculoskeletal Radiologist Needs to Know About the Vascular Anatomy of the Spine and Spinal Cord

This article describes the vascular anatomy of the spine and spinal cord, highlighting key structures and anatomical variations relevant to musculoskeletal radiologists. It covers the arterial and venous drainage systems, along with examples of vascular conditions affecting the spine. Understanding the vascular anatomy of the spine and spinal cord is crucial for accurate interpretation of imaging studies and safe spinal interventional procedures. Imaging techniques for evaluating vascular pathology of the spine are discussed and compared. Understanding vascular anatomy and the most common vascular disorders will lead to an accurate diagnosis and suggest the appropriate type of study needed for further characterization and/or patient management.

Successful technical note—Identification of the Adamkievicz artery with 1.5 Tesla MR angiography in a 14-month-old child

Posterior mediastinal tumors surgery may be complicated by their proximity to the artery of Adamkiewicz (AKA) and its segmental supplier, increasing the risk of ischemia of the spinal cord. We describe a case of preoperative identification of the AKA with magnetic resonance angiography (MRA) in a 14-month-old boy diagnosed with a thoracic neuroblastoma, thus allowing an accurate surgical planning in order to avoid injury to those vessels. Given the relatively high incidence of posterior mediastinal tumors in the pediatric age, MRA may establish itself as a viable alternative for this purpose, even in young children.

Aggressive vertebral hemangioma masquerading as neurological disease in a pediatric patient

Aggressive hemangioma is a rare vertebral lesion in pediatric patients which can present with deteriorating neurological function. It can mimic malignancy on imaging, particularly as it regularly has an extrasosseous soft tissue component. We present a case of a 13-year-old male who presented with a three month history of lower extremity weakness that was found to have an infiltrative mass at T10 with associated cord compression from epidural extension of the lesion. In this report we review the characteristic imaging findings associated with aggressive hemangioma, including its appearance on read-out segmented diffusion-weighted images. It is imperative that radiologists who interpret studies of children be aware that this lesion exists and what it looks like, as it can be associated with massive hemorrhage if encountered unexpectedly during surgery.

Use of Fenestrated Stent-Grafts for Preservation of Spinal Artery Flow During Endovascular Repair of Thoracoabdominal Aortic Disease

We illustrate the safety and feasibility of the application of fenestrated stent-grafts for the preservation of spinal artery flow during endovascular repair of thoracoabdominal aortic aneurysms (TAAA) in 2 patients deemed high-risk for spinal cord ischemia (SCI). In one case, an unstented fenestration was used in a 78-year-old male treated for distal stent-graft induced new entry tear. In the other case, a fenestration with a bridging stent-graft was used to revascularize a spinal artery in a 66-year-old female with Marfan disease and island patch aneurysm following open TAAA reconstruction. Both procedures were successful without any postoperative neurologic complication. The unstented fenestration led to a type III endoleak that required the relining of the aortic stent-graft 2 years later. The stented spinal fenestration was patent at a 5-year imaging follow-up.

Transarterial CT angiography for surgical planning of spinal dural arteriovenous fistula

OBJECTIVE

We report a novel method to provide excellent anatomical depiction of a dural arteriovenous fistula (dAVF) for surgical planning.

METHODS

A 78-year-old female presented with progressive back pain, deteriorating mobility and urinary incontinence with a background of obesity and severe osteoarthritis. Initial MRI suspected dAVF and subsequent spinal angiography encountered an extremely tortuous and arteriosclerotic aorta, hence catheterisation of the segmental-intercostal and lumbar vessels proved challenging. Contrast injection into the aortic arch via a pigtail catheter for arterial-phase CT angiogram of the descending aorta was performed.

RESULTS

This modality of imaging delineated the dAVF showing extensive involvement of the whole spine accounting for the patient's symptoms. Furthermore this allowed characterisation of bony anatomy in relation to the fistula facilitating precise surgical approach. The dAVF was successfully disconnected through a localised laminectomy centred over the lesion.

CONCLUSION

This specific technique for dAVF characterisation has not been previously reported, although trans-venous angiography has been used to some effect. In view of diagnostic and therapeutic technical difficulties that are often faced in such patients, this technique may be a useful alternative that is not only helpful in accurate diagnosis but helps in providing an invaluable guide for the surgical approach.

ADVANCES IN KNOWLEDGE

This case highlights the difficulties that one may be faced within cases of tortuous vasculature and the obese patient population. With this in mind we demonstrate how a unique hybridised technique may provide valuable alternative to the neurosciences team should such a future scenario arise.

Removal of Antiscatter Grids for Spinal Digital Subtraction Angiography: Dose Reduction without Loss of Diagnostic Value

Background Spinal digital subtraction angiography (DSA) exposes patients and operators to substantial amounts of radiation. Antiscatter grid (ASG) removal is used to decrease radiation exposure but may reduce image quality. Purpose To determine whether ASG removal during spinal DSA in adults reduces radiation dose while maintaining diagnostic image quality and whether dose reduction is related to body mass index (BMI). Materials and Methods This Health Insurance Portability and Accountability Act-compliant prospective study included adults undergoing spinal DSA between January and December 2016. Each procedure included an additional angiographic acquisition performed twice, once with and once without ASG, either documenting the artery of Adamkiewicz (no pathology group) or the condition leading to the procedure (pathology group). Dose differences between study acquisitions and the influence of BMI were evaluated via paired t test. Two neurointerventionalists blinded to acquisition protocols were asked to independently evaluate a sample of 40 study acquisitions (20 with ASG, 20 without ASG) from 20 randomly selected participants to (a) rate image quality, (b) categorize findings, and (c) determine whether images had been obtained with or without ASG. Percentage agreement on image quality, findings categorization, and ability to correctly identify the acquisition protocol was calculated for both readers. Results Fifty-three participants (mean age ± standard deviation, 51 years ± 15.2; 32 men) were evaluated. ASG removal reduced the mean dose per acquisition by approximately 33% (mean dose-area product and air kerma decreased from 202 to 135.6 µGy/m² and from 35.3 to 24 mGy, respectively; P < .001) independently of BMI (P = .3). Both readers evaluated all images (40 of 40) as being of diagnostic quality and correctly categorized findings in 19 of 20 (95%) cases. Overall percentage agreement for correct protocol identification was 60% (12 of 20) for grid-in and 45% (nine of 20) for grid-out images. Conclusion Antiscatter grid removal during spinal digital subtraction angiography decreased participants' radiation exposure while preserving diagnostic image quality. © RSNA, 2020.

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.

Symptomatic Vertebral Hemangioma of the Posterior Elements Sharing Blood Supply with a Radiculomedullary Artery

Vertebral hemangiomas are common lesions usually restricted to the vertebral body. They are characterized by proliferation of endothelial cells and subsequent expansion of vascular spaces within the bone. These lesions are usually clinically silent and are discovered incidentally. Only rarely are vertebral hemangiomas symptomatic. Here, we present the case of a 68-year-old female with an aggressive hemangioma causing neurologic deficit. The lesion was localized within the posterior spinal elements, with no involvement of the vertebral body. Transarterial embolization was deemed unsafe due to the close proximity of a prominent radiculomedullary artery. The patient was treated with posterior decompression at T4-T6.

Desenvolvimento de modelo clínico para predição da possibilidade de identificação da artéria de Adamkiewicz por angiotomografia

Contexto

Diferenças morfológicas da artéria de Adamkiewicz (AKA) entre a população portadora e não portadora de doença aórtica têm importância clínica, influenciando as complicações neuroisquêmicas da medula espinhal em procedimentos operatórios. Ainda não é conhecida a correlação entre parâmetros clínicos e a previsibilidade da identificação dessa artéria pela angiotomografia.

Objetivo

Desenvolver um modelo matemático que, através de parâmetros clínicos correlacionados com aterosclerose, possa prever a probabilidade de identificação da AKA em pacientes submetidos a angiotomografias.

Método

Estudo observacional transversal utilizando banco de imagens e dados de pacientes. Foi feita análise estatística multivariada e criado modelo matemático logit de predição para identificação da AKA. Variáveis significativas foram utilizadas na montagem da fórmula para cálculo da probabilidade de identificação. O modelo foi calibrado, e a discriminação foi avaliada pela curva receiver operating characteristic (ROC). A seleção das variáveis explanatórias foi guiada pela maior área na curva ROC (p = 0,041) e pela significância combinada das variáveis.

Resultados

Foram avaliados 110 casos (54,5% do sexo masculino, com idade média de 60,97 anos e etnia com coeficiente B -2,471, M -1,297, N -0,971), com AKA identificada em 60,9%. Índice de massa corporal: 27,06 ± 0,98 (coef. -0,101); fumantes: 55,5% (coef. -1,614/-1,439); diabéticos: 13,6%; hipertensos: 65,5% (coef. -1,469); dislipidêmicos: 58,2%; aneurisma aórtico: 38,2%; dissecção aórtica: 12,7%; e trombo mural: 24,5%. Constante de 6,262. Fórmula para cálculo da probabilidade de detecção: (e−(Coef. Etnia+(Coef. IMC×IMC)+Coef.fumante+Coef.HAS+Coef.dislip+Constante)+1)−1 . O modelo de predição foi criado e disponibilizado no link https://vascular.pro/aka-model .

Conclusão

Com as covariáveis etnia, índice de massa corporal, tabagismo, hipertensão arterial e dislipidemia, foi possível criar um modelo matemático de predição de identificação da AKA com significância combinada de nove coeficientes (p = 0,042).

Ischaemia of the medullary cone after stent-graft implantation in a patient with abdominal aortic aneurysm - a case study

Preoperative visualization of the Adamkiewicz artery - the vessel which is to a great extent responsible for supplying blood to the medullary cone - is an important step which must be taken before initiating restorative procedures in the aorta. We present a case of a 67-year-old patient who underwent an intravascular stent-graft implantation procedure, due to clinical signs of abdominal aortic aneurysm. Routine pre-operative computed tomography examination failed to demonstrate the Adamkiewicz artery. On the second day after the surgery, as a result of unexpected clinical deterioration, an magnetic resonance imaging examination of the lumbar spine was carried out. Based on the magnetic resonance imaging images and clinical manifestations the diagnosis of ischaemia of the medullary cone was made. In our work we also present a deep analysis of the anatomy of small-sized vessels supplying blood to the spinal cord and discuss effective techniques which enable visualization of the Adamkiewicz artery.

Intercostal artery pseudoaneurysm with spontaneous resolution in the setting of an artery of Adamkiewicz

We report an extremely unique and previously unreported case of a pseudoaneurysm arising from an intercostal artery that also gave origin to the artery of Adamkiewicz. Due to the potential risk of losing the artery of Adamkiewicz, a conservative approach was indicated. On short interval follow-up imaging, the pseudoaneurysm and associated hematoma spontaneously resolved with preservation of the intercostal artery. We performed a literature review of the natural course of pseudoaneurysm as well as their occurrence in the intercostal arteries.

Feeding Arteries of the Spinal Cord at CT Angiography before and after Thoracic Aortic Endografting

Purpose:

To study the visualization of spinal cord feeding arteries in patients with complex thoracic aortic pathology undergoing endovascular aortic repair (EVAR) using an optimized protocol for multislice computed tomographic angiography (MSCTA).

Methods:

Eighteen consecutive patients (13 men; mean age 63 years, range 45–79) with aortic type B dissections (n=5), chronic expanding aortic dissections (n=5), thoracic aortic aneurysms (n=6), or penetrating aortic ulcers (n=2) underwent 16-slice CTA before and after (mean interval 9 days) EVAR. Pulse rate and neurological status were documented. Quantitative density measurements were taken at regions of interest (ROI) in the ascending thoracic aorta and at the level of the diaphragm. Two experienced radiologists qualitatively assessed the posterior intercostal arteries (PIA; fully visible, partially visible, non-visible), dorsal branches (DB; visible/non-visible), and artery of Adamkiewicz (AKA; visible/non-visible) on multiplanar reformations and maximum intensity projection reconstructions.

Results:

MSCTA was performed successfully in 17/18 patients before and after EVAR (1 patient was excluded after EVAR owing to rising creatinine levels). Before EVAR, MSCTA revealed 197/203 PIAs within the stented area, of which 179 were fully and 18 partially visible. No significant (p=0.37) difference was noted for overall PIA detection within the stented area on post-EVAR MSCTA (185/203 PIA), although only 124 were fully and 61 partially visible. Similar results were obtained for DB visualization. The AKA were seen in 10/17 patients pre EVAR and 9/17 post EVAR. In 2 patients, the AKA was localized within the stented aortic segment. ROI analysis revealed contrast densities of 427±89 HU and 398±84 HU on pre- and post-EVAR MSCTA, respectively. No neurological events were observed.

Conclusion:

The majority of posterior intercostal arteries and dorsal branches remain open after EVAR due to retrograde perfusion. High-resolution MSCTA permits accurate pre-and post-EVAR visualization of spinal cord feeding arteries in patients with thoracic aortic pathology.

Visualization of Lumbar Artery Variations by Contrast-Enhanced Multi-detector Row Computed Tomography

PURPOSE

This study was designed to identify the anatomical variations of lumbar arteries on contrast-enhanced multi-detector row computed tomography (MDCT).

MATERIALS AND METHODS

Consecutive 100 colon cancer patients underwent preoperative 3-dimensional navigation studies, which include CT colonography (CTC) and CT angiography (CTA) for evaluation of anatomical relationship between the colon cancer and mesenteric vasculatures. After exclusion of inappropriate cases, 84 cases (33 women and 51 men; mean age, 64 years) were finally analyzed. The visualization of lumbar arteries from the CTA was scored based on the agreement of two radiology specialists. Also the presence or absence of left and right common trunk of each lumbar artery was evaluated.

RESULTS

Visualization scores on both sides of L1 were significantly lower than those of L2-L4. No significant difference could be found on visualization of L1 lumbar arteries between the young and the elderly group. The common trunk tended to be in the lower lumbar levels (L1 in 2.4%, L2 in 9.5%, L3 in 11%, and L4 in 23%).

CONCLUSION

The development and variation of lumbar arteries can be evaluated with CTA. Furthermore, CTA can provide sufficient anatomical information on variations of the lumbar arteries prior to surgery or catheterization.

Spinal intraarterial computed tomography angiography as an effective adjunct for spinal angiography

OBJECT

Spinal digital subtraction angiography (DSA) is indispensable for the precise diagnosis of spinal vascular lesions and the assessment of blood supply to the spinal cord. However, comprehensive spinal DSA covering multiple segments requires repetition of selective catheterization into small segmental arteries, which is time consuming, sometimes difficult, and hazardous. The authors investigated the usefulness of CT angiography with intraarterial contrast injection (IA-CTA) as a preliminary study preceding spinal DSA. With the advent of multidetector CT, it is feasible to obtain images of the spinal cord vasculature instantaneously overa number of segments.

METHODS

A total of 56 patients with lesions involving the spinal vasculature underwent IA-CTA with 64- or 320-row detector CT in advance of comprehensive spinal DSA. Contrast material was injected via a pigtail catheter placed at the aorta in proximity to the segments of interest. Scanning was repeated twice to obtain arterial- and venous-phase images to differentiate between the arterial and venous components. The spinal arteries were identified by paging the various multiplanar reconstruction images and tracing the vessels from the aorta. Spinal DSA was subsequently performed by guiding selective catheterization to the feeding segments in reference to the IA-CTA findings. Visualization of the segmental arteries, normal spinal arteries, and abnormal vessels during IA-CTA was investigated and compared with that obtained during spinal DSA.

RESULTS

In all 56 patients, spinal IA-CTA successfully enabled visualization of the spinal vessels, including the radicular arteries and the anterior spinal artery. Below the aortic arch, all segmental arteries were identified clearly. The segmental arteries, radiculomedullary arteries, spinal arteries, and abnormal vessels were traced from the aorta, which would be the target of selective catheterization. In 3 (6.8%) patients, IA-CTA revealed severe aortic atherosclerosis and occlusion of some segmental arteries. The information obtained was useful for directing selective catheterization studies. The findings of IA-CTA corresponded well with those of spinal DSA.

CONCLUSIONS

IA-CTA is a useful adjunct to spinal DSA for surveying the vasculature surrounding the spinal cord and for orienting selective catheterization. IA-CTA can complement spinal DSA, curtail unnecessary segmental injections, and thus reduce procedural complications.

Anatomia da circulação medular

ResumoA intrincada anatomia tridimensional da irrigação medular é frequentemente explanada na literatura com diferentes nomenclaturas e devido a sua alta relevância no estudo da isquemia medular, o estudo da terminologia se faz necessário para melhor compreensão do tema. A artéria de Adamkiewicz, também chamada de artéria radicular magna, é a via principal. Foi realizada a revisão da literatura com equiparação das nomenclaturas utilizadas e elaboração de descrição acurada e sumarizada do conhecimento atual sobre a vascularização medular.

The Impact of Preoperative Angiographic Identification of the Artery of Adamkiewicz on Surgical Decision Making in Patients Undergoing Thoracolumbar Corpectomy

STUDY DESIGN

Retrospective study.

OBJECTIVE

To investigate the impact of spinal angiography on selection of surgical side in patients undergoing thoracolumbar corpectomy.

SUMMARY OF BACKGROUND DATA

The artery of Adamkiewicz provides the major blood supply to the thoracolumbar spinal cord. Its location makes it vulnerable to injury during surgical procedures. Preoperative diagnostic spinal angiography is often used to determine the level and lateralization of the artery.

METHODS

Data were gathered regarding level and laterality of the Adamkiewicz artery in 34 patients who underwent lateral extracavitary approaches to the thoracolumbar spine, preceded by diagnostic spinal angiography for localization of that artery. Two experienced spine surgeons were retrospectively polled regarding ideal side of approach for each case. This was compared with the actual side that was selected after angiographic localization.

RESULTS

The artery was successfully identified in 71% of patients. The artery was most commonly located on the left side (83%) between T9 and L1 (83%). Diagnostic angiography seemed to have influenced surgical decision making in 54% of cases. In 21% of patients, there was no need to alter the side of approach. In the remaining 25%, the surgical plan was not altered on the basis of angiographic data, presumably due to anatomic limitations. No angiography- or surgery-related complications occurred in any of the patients.

CONCLUSION

Preoperative spinal angiography seems to impact surgical decision making with regard to alteration of the side of approach in patients undergoing thoracolumbar corpectomy via lateral extracavitary approaches.

LEVEL OF EVIDENCE

4.

Visualization of the segment IV hepatic artery using 128-section MDCT angiography

AIM

To visualize the segment IV hepatic artery and to evaluate the variations in anatomy using multidetector computed tomography (MDCT) angiography.

MATERIALS AND METHODS

Six hundred and seventeen patients (381 men and 236 women; mean age 62.7 ± 8.1 years; age range 22-92 years) who underwent MDCT angiography performed using a 128-section MDCT system were included in the study. The segment IV hepatic arteries of 453 patients with adequate image quality were displayed using volume rendering (VR), maximum intensity projection (MIP), and multiplanar reconstruction (MPR), and were analysed regarding the origination and variation of the arteries by two radiologists and an anatomist retrospectively.

RESULTS

Segment IV arteries were categorized into five different types according to their points of origin: left hepatic artery (LHA, 51.66%), right hepatic artery (RHA, 30.68%), proper hepatic artery (PHA, 5.3%), dual (12.14%), and triple (0.22%). Segment IV arteries arising from normal LHA, RHA, and PHA were found in 73.73% of patients, and those arising from variant LHA or RHA were found in 26.27%. The patterns RN2, LA2, LA3, LA4, PN2, PV1, DA1, DA2, DV3, and DV4 were first reported in the present study.

CONCLUSIONS

MDCT angiography can evaluate normal as well as anatomical variants of segment IV arteries. Predicting arterial patterns of segment IV of the liver is important in planning and performing all radiological and surgical procedures in the liver, especially in hemi-liver graft procedures.

Duplicated origin of a radiculomedullary artery supplying a perimedullary arteriovenous fistula: angiographic observation and developmental considerations

The angiographic observation of a radiculomedullary artery variation found in a patient with a spinal cord vascular malformation is presented. A posterior radiculomedullary artery arising from the left L2 intersegmental artery had a duplicated origin. Two radicular trunks were seen aiming towards the neural foramen: a dominant anterior one providing a retrocorporeal artery and the anterior limb of the radicular artery, and a smaller posterior one branching off a prelaminar artery and the posterior limb of the radicular artery. The two limbs then joined to continue as a single posterior radiculomedullary artery, which participated in the vascularization of the vascular malformation. The clinical and developmental aspects of this exceptional variant are discussed.

Neurological complications of thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

Open repair of extensive thoracoabdominal and thoracic aneurysm: a preliminary single-center experience with femorofemoral distal aortic perfusion with oxygenator and without cerebrospinal fluid drainage

Thoracoabdominal aortic aneurysms (TAAA) and extensive thoracic descending aortic aneurysms (TDA) are not accessible through standard endovascular treatment. Fenestrated and branched endograft technology was developed rapidly without widespread application. The aim of this study was to review our open repair (OR) experience of TAAA and TDA. A total of 28 patients who underwent elective OR of TAAA or TDA between January 2001 and January 2009 were analyzed retrospectively. The mean age of the patients was 65.5 years (three women). The anatomic locations of the aneurysms were as follows: six in thoracic descending aorta and 22 in thoracoabdominal aorta (14 TAAA I, two TAAA II, six TAAA III). TDA (40 patients) available for ordinary endovascular treatment and TAAA IV (35 patients) were excluded from this study. To focus on spinal cord vascularization, 25 patients were submitted for angiography. Three patients suffering from back pain required quick treatment and were excluded from angiographic investigations. Angiography procedures were contributive in 23 patients (92%). Surgical repairs were driven through left thoraco-phreno-laparotomy, with the adjunct of distal aortic perfusion (femorofemoral bypass) including the use of an oxygenator and sequential aortic cross-clamping. Cerebrospinal fluid drainage was not used in this experience. The 30-day mortality rate was 14.3% (four of 28 patients): one multiorgan failure and three pulmonary sepsis. An immediate postoperative paraplegia occurred, affecting a patient with TDA who was previously submitted for infrarenal aorta replacement, despite angiographic identification and revascularization of intercostal artery destined to spinal artery. The 1-year survival rate was 82.1% (23 of 28 patients). In the preliminary experience of this study, OR of extensive TAAA and TDA with distal aortic perfusion and an oxygenator without use of cerebrospinal fluid drainage was associated with a significant perioperative mortality rate (14.2%), a reasonable rate of paraplegia (3%), and 1-year survival rate of 82.1%.

Accuracy and pitfalls of multidetector-row computed tomography in detecting spinal dural arteriovenous fistulas

Object

The purpose of this study was to evaluate the accuracy of multidetector-row CT angiography (MDCTA) in demonstrating spinal dural arteriovenous fistulas (SDAVFs).

Methods

The authors studied 10 patients with SDAVFs, including 2 with spinal epidural AVFs, who underwent preoperative MR imaging, MDCTA, and digital subtraction angiography (DSA). In the evaluation of coronal sections of multiplanar reformation MDCTA images, inspection was focused on the presence of the following findings: 1) dilated perimedullary veins in the spinal canal; 2) focal enhancement of the nerve root, suggesting the location of the AVF, around the dural sleeve; and 3) a radicular vein that drains the AVF into perimedullary veins. The utility of MDCTA was assessed by comparing its findings with those of DSA in each case.

Results

Digital subtraction angiography confirmed that the AVFs were located in the thoracic spine in 4 patients and in the lumbar spine in 6 patients, and MDCTA detected dilated perimedullary veins in all 10 patients. In 8 patients, there was focal enhancement of the nerve root. The radicular vein that drains the AVF into the perimedullary veins was found in 8 cases. In 8 cases, the MDCTA-derived level and side of the AVF and its feeder corresponded with those shown by DSA. In 2 patients, however, the MDCTA-derived side of the feeder was on the side contralateral to the feeding artery confirmed by DSA. These lesions were interpreted as spinal epidural AVFs with perimedullary drainage. In 2 cases, MDCTA could not detect the multiplicity of their feeders.

Conclusions

The use of MDCTA preceding DSA can be helpful to focus the selective catheter angiography on certain spinal levels. However, one should keep in mind that epidural AVFs with perimedullary drainage may resemble SDAVFs and also that MDCTA cannot exclude the possibility of multiple feeders. Further research should elucidate how broadly selective angiography should explore around the MDCTA-suggested target.

Assessment of intracranial arterial stenosis with multidetector row CT angiography: a postprocessing techniques comparison

BACKGROUND AND PURPOSE

It was demonstrated the some patients with stroke have intracranial stenosis of 50% or greater and the identification of intracranial arterial stenosis is extremely important in order to plan a correct therapeutical approach. The aim of this study was to assess the image quality and intertechnique agreement of various postprocessing methods in the detection of intracranial arterial stenosis.

MATERIAL AND METHODS

Eighty-five patients who were studied by using a multidetector row CT scanner were retrospectively analyzed. A total of 2040 segments were examined in the 85 subjects. Intracranial vasculature was assessed by using MPR, CPR, MIP, and VR techniques. Two radiologists reviewed the CT images independently. Cohen weighted kappa statistic was applied to calculate interobserver agreement and for image accuracy for each reconstruction method. Sensitivity, specificity, PPV, and NPV were also calculated by using the consensus read as the reference.

RESULTS

Two hundred fifteen (10.5%) stenosed artery segments were identified by the observers in consensus. The best intermethod kappa values between observers 1 and 2 were obtained by VR and MIP (kappa values of 0.878 and 0.861, respectively), whereas MPR provided the lowest value (kappa value of 0.282). VR showed a sensitivity for detecting stenosed segments of 88.8% and 91.6% for observers 1 and 2, respectively. The highest positive predictive value was also obtained by VR at 95% and 99% for observers 1 and 2, respectively. Image accuracy obtained by using VR was the highest among all reconstruction methods in both observers (185/255 and 177/255 for observers 1 and 2, respectively).

CONCLUSIONS

The results of our study suggest that VR and MIP techniques provide the best interobserver and intertechnique concordance in the analysis of intravascular cranial stenosis.

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.

Complications and pitfalls of lumbar interlaminar and transforaminal epidural injections

Lumbar interlaminar and transforaminal epidural injections are used in the treatment of lumbar radicular pain and other lumbar spinal pain syndromes. Complications from these procedures arise from needle placement and the administration of medication. Potential risks include infection, hematoma, intravascular injection of medication, direct nerve trauma, subdural injection of medication, air embolism, disc entry, urinary retention, radiation exposure, and hypersensitivity reactions. The objective of this article is to review the complications of lumbar interlaminar and transforaminal epidural injections and discuss the potential pitfalls related to these procedures. We performed a comprehensive literature review through a Medline search for relevant case reports, clinical trials, and review articles. Complications from lumbar epidural injections are extremely rare. Most if not all complications can be avoided by careful technique with accurate needle placement, sterile precautions, and a thorough understanding of the relevant anatomy and contrast patterns on fluoroscopic imaging.

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.

Multidetector-Row CT Angiography Diagnostic Sensitivity in Evaluation of Renal Artery Stenosis

PURPOSE

The aim of this study was to assess the image quality and interobserver agreement of various multidetector-row computed tomographic angiography postprocessing techniques in the diagnosis of renal artery stenosis (RAS).

MATERIALS AND METHODS

We studied 36 patients (21 men and 15 women; mean age, 49 years) who underwent computed tomography angiography to assess renal arteries for suspected RAS. Patients were analyzed by using a multidetector-row computed tomography. Computer tomographic scans were obtained after intravenous bolus administration of 110 to 140 mL of nonionic contrast material using a 4- to 6-mL/s flow rate. We assessed every patient by using axial scans, multiplanar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering (VR) techniques. For each patient and for each reconstruction method, the image quality of the main renal artery was scored as 0 for bad-quality, 1 for poor-quality, 2 for good-quality, and 3 for excellent-quality images. Two radiologists reviewed computed tomographic images independently. We calculated interobserver agreement and kappa value. We correlated the stenosis degree observed by the 2 readers with the type of reconstruction used.

RESULTS

Overall number of renal arteries studied was 72, and we detected 24 RAS. Quality images obtained an overall (averaged between the 2 observers) value of 133 of 216, 163 of 216, and 145 of 216 for MPR, MIP, and VR, respectively. Our data underlined a statistical difference between MPR images and VR images (P < 0.001). Moreover, we noticed that the images classified as excellent were obtained from a vessel with 350 Hounsfield units or higher. Kappa value was good in MIP and VR methods evaluation but poor with the use of MPR.

CONCLUSIONS

Reformatting techniques usually provided a high visual impact, and in our study, MIP and VR showed the best diagnostic interobserver agreement in quality and reproducibility of stenosis degree.

Multi-detector-row CT angiography as a preoperative evaluation for spinal arteriovenous fistulae

The role of multi-detector-row computed tomographic angiography (MDCTA) in spinal vascular malformations has not yet been determined. We present a report on a short series of spinal arteriovenous fistulae (AVF) evaluated by MDCTA. With 4-row and 16-row MDCTA, three cases of spinal dural AVF and one case of perimedullary AVF were examined. Each case was also examined by magnetic resonance (MR) imaging and spinal catheter angiography. In two patients with spinal dural AVF, including one patient with angiographically occult AVF, MDCTA successfully located the site of the AVF in a multi-planar reformation image. MDCTA failed to locate the remaining case of spinal dural AVF, probably due to the small amount of shunting blood volume at the fistula. In a patient with perimedullary AVF, MDCTA visualized the broad range of the lesion, including the anterior spinal artery as a single feeder, the fistulous point, and the single perimedullary draining vein. In conclusion, although conventional spinal angiography might be still essential, MDCTA provides useful information for the surgeon in treatment of the spinal dural AVF. Further accumulation of clinical cases is required to determine the potential of MDCTA for perimedullary AVF. MDCTA should be considered as a choice of investigation in the evaluation of spinal AVFs.