Assessing Vascularity of Osseous Spinal Metastases with Dual-Energy CT-DSA: A Pilot Study Compared with Catheter Angiography

Association of CT-DSA vascular assessment and perioperative outcomes in metastatic spinal surgery

INTRODUCTION

Computed tomography-digital subtraction angiography (CT-DSA) is a radiological method for assessing spinal metastatic tumor vascularity. The study aimed to investigate the association between CT-DSA results and perioperative outcomes in spinal metastatic surgery.

MATERIAL AND METHODS

Patients who underwent spinal metastatic operations with preoperative CT-DSA examinations at any time between January 2018 to December 2022. CT-DSA was classified into five grades ranging from grade 0 to grade 4. Grades 3 and 4 were indicative of hypervascularity. We analyzed the perioperative outcomes of intraoperative blood loss amount, massive hemorrhage (≥2500 ml) occurrence, blood transfusion status, operation time, hospital stay duration, and 30-day and 60-day mortality rates. Logistic regression analyses were conducted to identify factors affecting the likelihood of massive hemorrhage in conjunction with CT-DSA.

RESULTS

Data from 212 operations involving 209 patients were analyzed. In total, 30, 36, 66, 56, and 24 operations had CT-DSA grades from grade 0 to grade 4, respectively. Eighty (38 %) studies were indicative of hypervascularity. CT-DSA grade was positively correlated with the amount of operative blood loss, the occurrence of massive hemorrhage, and the amount of blood in blood transfusion (p < 0.05). However, CT-DSA grades was not significantly associated with operation duration or mortality rate. A multivariable analysis indicated that factors such as hemoglobulin, hypervascular pathology, and spinal instability neoplastic scores were positively correlated with CT-DSA grade. CT-DSA grade (odds ratio: 2.37, p = 0.02), spinal metastatic invasiveness index, and tumor size (≥50 mL) were found to be independent predictors in a multivariable logistic regression analysis where factors associated with massive hemorrhage were included. Hypervascular pathology type was not significantly associated with the likelihood of hemorrhage in the univariable and multivariable analyses.

CONCLUSIONS

CT-DSA serves as an effective tool for assessing vascularity, and is associated with intra-operative blood loss and likelihood of experiencing massive hemorrhage. The predictive capability of CT-DSA surpasses that of traditional histopathology classifications, making it a useful method for preoperative planning in spinal metastatic surgeries.

Computed Tomography Perfusion Combined With Preoperative Embolization for Reducing Intraoperative Blood Loss in Separation Surgery for Thoracolumbar Metastases

STUDY DESIGN

A prospective consecutive case study.

OBJECTIVE

This study aimed to assess the accuracy of computed tomography perfusion (CTP) in evaluating the vascularity of thoracolumbar metastases and to determine the impact of combining CTP with preoperative embolization on reducing intraoperative blood loss during separation surgery.

SUMMARY OF BACKGROUND DATA

Surgery for thoracolumbar metastases is a complex procedure with the potential for substantial blood loss. Therefore, assessing tumor vascularity before surgery and taking measures to minimize intraoperative blood loss is essential.

METHODS

A total of 62 patients with thoracolumbar metastases were prospectively enrolled. All patients underwent separation surgery using the posterior approach. Before surgery, the vascularity of the metastases was evaluated using CTP. On the basis of the CTP results, patients were categorized into hypervascular and hypovascular groups. Preoperative angiography and embolization were performed for the hypervascular group. Clinical data were abstracted, including intraoperative blood loss, perioperative complications, visual analog scale score, neurological status, and the accuracy of vascularity evaluation by CTP confirmed by angiography. χ 2 testing was used to compare categorical variables, whereas independent sample t tests were used to compare continuous variables, with paired t tests used to assess differences from preoperative to postoperative time points.

RESULTS

The mean intraoperative blood loss was 485±167 and 455±127.6 mL in the two groups, respectively. The accuracy of vascularity evaluation by CTP was 100%. In the hypervascular group, 80.6% of the patients experienced at least one level of improvement in neurological status, while the hypovascular group had 81.5% of patients with similar improvement. None of the patients experienced neurological deterioration. There was a significant reduction in visual analog scale scores in both groups after the operation.

CONCLUSIONS

The vascularity of thoracolumbar metastases could be accurately evaluated using noninvasive CTP. When combined with preoperative embolization, this approach effectively and safely reduced intraoperative blood loss in the setting of separation surgery.

Diagnostic performance of computed tomography-digital subtraction angiography and conventional magnetic resonance imaging for evaluating the vascularity of osseous spinal tumors

BACKGROUND AND PURPOSE

Patients with hypervascular spinal tumors may have severe blood loss during tumor resection, which increases the risks of perioperative morbidity and mortality. However, the preoperative evaluation of tumor vascularity may be challenging; moreover, the reliability of the data obtained in conventional preoperative noninvasive imaging is debatable. In this study, we compared conventional magnetic resonance imaging (MRI) and subtraction computed tomography angiography (CTA) in terms of their performance in vascularity evaluation. The catheter digital subtraction angiography (DSA) technique was used as a reference standard.

METHODS

This study included 123 consecutive patients with spinal tumor who underwent subtraction CTA, catheter DSA, and subsequent surgery between October 2015 and October 2021. Data regarding qualitative and semiquantitative subtraction CTA parameters and conventional MRI signs were collected for comparison with tumor vascularity graded through catheter DSA. The diagnostic performance of qualitative CTA, quantitative CTA, and conventional MRI in assessing spinal tumor vascularity was analyzed.

RESULTS

Qualitative subtraction CTA was the best noninvasive imaging modality in terms of diagnostic performance (area under the receiver operating characteristic curve [AUROC], 0.95). Quantitative CTA was relatively inferior (AUROC, 0.87). MRI results had low reliability (AUROC, 0.51 to 0.59). Intratumoral hemorrhage and prominent foraminal venous plexus were found to be the specific signs for hypervascularity (specificity 93.2%).

CONCLUSIONS

Qualitative subtraction CTA offers the highest diagnostic value in evaluating spinal tumor vascularity, compared to quantitative CTA and MRI. Although conventional MRI may not be a reliable approach, certain MRI signs may have high specificity, which may be crucial for assessing spinal tumor vascularity.

Delay of Surgery for Spinal Metastasis due to the COVID-19 Outbreak Affected Patient Outcomes

OBJECTIVE

The present study is to analyze the effects of the coronavirus disease 2019 (COVID 2019) outbreak and the subsequent lockdown on the outcomes of spinal metastasis patients.

METHODS

The study was a retrospective analysis of data from a prospective cohort study. All patients underwent surgical intervention for spinal metastases between January 2019 and December 2021 and had at least 3 months of postoperative follow-up. The primary outcome was overall mortality during the 4 different stages (pre-COVID-19 era, COVID-19 pandemic except in Taiwan, national lockdown, lifting of the lockdown). The secondary outcomes were the oncological severity scores, medical/surgical accessibility, and patient functional outcome during the 4 periods as well as survival/mortality.

RESULTS

A total of 233 patients were included. The overall mortality rate was 41.20%. During the Taiwan lockdown, more patients received palliative surgery than other surgical methods, and no total en bloc spondylectomy was performed. The time from surgeon visit to operation was approximately doubled after the COVID-19 outbreak in Taiwan (75.97, 86.63, 168.79, and 166.91 hours in the 4 periods, respectively). The estimated survival probability was highest after the national lockdown was lifted and lowest during the lockdown. In the multivariate analysis, increased risk of mortality was observed with delay of surgery, with emergency surgery having a higher risk with delays above 33 hours, urgent surgery (below 59 and above 111 hours), and elective surgery (above 332 hours).

CONCLUSION

The COVID-19 pandemic and related policies have altered daily clinical practice and negatively impacted the survival of patients with spinal metastases.

Efficacy of preoperative embolization for metastatic spinal tumor surgery using angiographic vascularity assessment

OBJECTIVES

Preoperative embolization (PE) for metastatic spinal tumors is a method of minimizing intraoperative blood loss during aggressive surgery. This study specified angiographic standards and investigated the influence of these and other factors on blood loss in patients with spinal metastases and various pathologies.

METHODS

The cohort comprised 126 consecutive patients receiving PE from 2015 to 2021. Their clinical, surgical, and angiographic characteristics were reviewed. Standard angiographic grading was used for vascularity assessment. Degree of embolization was divided into complete (≥ 90%), near complete (67 to < 90%), and partial (< 67%). Logistic regression analysis was used to investigate factors predictive of massive blood loss (> 2500 mL). A proportional odds model was used to assess factors predictive of the degree of embolization.

RESULTS

Mean intraoperative blood loss was 1676 mL. Among the patients, 62 had hypervascular tumors and 64 had nonhypervascular tumors, according to the angiographic classification. Intraoperative blood loss differed significantly with embolization degree, both overall (p < 0.001) and in the hypervascular and nonhypervascular groups (p = 0.01 and 0.03). Angiographic hypervascularity, spinal metastasis invasiveness index, and embolization degree were significant predictors of massive blood loss in univariate analysis, but only embolization degree was significant in multivariate analysis. Only the presence of the radiculomedullary artery at the target level was significant in both the univariate and multivariate analyses for embolization degree.

CONCLUSIONS

In addition to pathological classification, angiographic vascularity assessment is valuable. Although complete embolization is a reasonable goal, it is challenging to achieve in cases of visible radiculomedullary artery.

KEY POINTS

• Angiography has a supplementary role in vascularity assessment for spinal metastatic surgery. • Better embolization degree is associated with less intraoperative blood loss in both angiographic hypervascular and nonhypervascular groups. • Presence of radiculomedullary artery in the target level causes worse embolization outcome.

Freehand Minimally Invasive Pedicle Screw Fixation and Minimally Invasive Decompression for a Thoracic or Lumbar Vertebral Metastatic Tumor From Hepatocellular Carcinoma

Objective: To compare freehand minimally invasive pedicle screw fixation (freehand MIPS) combined with percutaneous vertebroplasty (PVP), minimally invasive decompression, and partial tumor resection with open surgery for treatment of thoracic or lumbar vertebral metastasis of hepatocellular carcinoma (HCC) with symptoms of neurologic compression, and evaluate its feasibility, efficacy, and safety.

Methods: Forty-seven patients with 1-level HCC metastatic thoracolumbar tumor and neurologic symptoms were included between February 2015 and April 2017. Among them, 21 patients underwent freehand MIPS combined with PVP, minimally invasive decompression, and partial tumor resection (group 1), while 26 patients were treated with open surgery (group 2). Duration of operation, blood loss, times of fluoroscopy, incision length, and stay in hospital were compared between the two groups. Pre- and postoperative visual analog scale (VAS) pain score, Oswestry Disability Index (ODI), American Spinal Injury Association (ASIA) grade, ambulatory status, and urinary continence were also recorded. The Cobb angle and central and anterior vertebral body height were measured on lateral radiographs before surgery and during follow-ups.

Results: Patients in group 1 showed significantly less blood loss (195.5 ± 169.1 ml vs. 873.1 ± 317.9 ml, P = 0.000), shorter incision length (3.4 ± 0.3 vs. 13.6 ± 1.8 cm, P = 0.000), shorter median stay in hospital (4–8/6 vs. 8–17/12 days, P = 0.000), more median times of fluoroscopy (5–11/6 vs. 4–7/5 times, P = 0.000), and longer duration of operation (204.8 ± 12.1 vs. 171.0 ± 12.0 min, P = 0.000) than group 2. Though VAS significantly decreased after surgery in both groups, VAS of group 1 was significantly lower than that of group 2 immediately after surgery and during follow-ups (P < 0.05). Similar results were found in ODI. No differences in the neurological improvement and spinal stability were observed between the two groups.

Conclusion: Freehand MIPS combined with PVP, minimally invasive decompression, and partial tumor resection is a safe, effective, and minimally invasive method for treating thoracolumbar metastatic tumors of HCC, with less blood loss, better pain relief, and shorter length of midline incision and stay in hospital.

Primary intraosseous meningioma of the vertebra: illustrative case

BACKGROUND

Primary intraosseous meningiomas (PIMs) are rare, and PIMs of the vertebrae have not yet been reported. The authors report a case of primary meningioma arising from the vertebrae.

OBSERVATIONS

A 49-year-old man presented with lower back pain and numbness in both lower extremities. Lumbar spine magnetic resonance imaging revealed an L2 pathological fracture with epidural and paraspinal invasion. The patient had undergone a first palliative decompression and fixation surgery, and the diagnosis turned out to be a World Health Organization grade III anaplastic meningioma based on histopathology. The tumor had progressed after first operation and radiation therapy, and the patient was referred to the authors’ institute for excision. The patient had an uneventful postoperative course after a revisional total en bloc spondylectomy of L2.

LESSONS

The authors present a rare case of PIM of the vertebrae with epidural and paraspinal invasion. Careful preoperative assessment and surgical planning is crucial for successful patient management.

Subtraction iodine imaging with area detector CT to improve tumor delineation and measurability of tumor size and depth of invasion in tongue squamous cell carcinoma

Purpose

Tumor size and depth of invasion (DOI) are mandatory assessments for tumor classification in tongue cancer but are often non-assessable on CT due to dental artifacts. This study investigated whether subtraction iodine imaging (SII) would improve tumor delineation and measurability.

Materials and methods

Fifty-seven consecutive patients with tongue cancer, who underwent scanning with a 320-row area detector CT with contrast administration and were treated with surgical resection, were retrospectively evaluated. CT was reconstructed with single-energy projection-based metallic artifact reduction (sCT). SII was generated by subtracting the pre-contrast volume scans from the post-contrast volume scans using a high-resolution deformable registration algorithm. MRI scans were also evaluated for comparing the ability of measurements. Two radiologists visually graded the tumor delineation using a 5-point scale. Tumor size and DOI were measured wherever possible. The tumor delineation score was compared using the Wilcoxon signed-rank method. Spearman’s correlations between imaging and pathological measurements were calculated. Intraclass correlation coefficients of measurements between readers were estimated.

Results

The tumor delineation score was greater on sCT-plus-SII than on sCT alone (medians: 3 and 1, respectively; p < 0.001), with higher number of detectable cases observed with sCT-plus-SII (36/57 [63.2%]) than sCT alone (21/57 [36.8%]). Tumor size and DOI measurability were higher with sCT-plus-SII (29/57 [50.9%]) than with sCT alone (17/57 [29.8%]). MRI had the highest detectability (52/57 [91.2%]) and measurability (46/57 [80.7%]). Correlation coefficients between radiological and pathological tumor size and DOI were similar for sCT (0.83–0.88), sCT-plus-SII (0.78–0.84), and MRI (0.78–0.90). Intraclass correlation coefficients were higher than 0.95 for each modality.

Conclusions

SII improves detectability and measurability of tumor size and DOI in patients with oral tongue squamous cell carcinoma, thus increasing the diagnostic potential. SII may also be beneficial for cases unevaluable on MRI due to artifacts or for patients with contraindications to MRI.

Spontaneous closure of an incidental high-flow paravertebral arteriovenous fistula caused by vertebral giant cell tumor curettage: illustrative case

BACKGROUND

Paravertebral arteriovenous fistula (AVF) after spinal surgery is rarely reported in the literature. Its natural course is largely unknown.

OBSERVATIONS

The authors report a 31-year-old woman with a high-flow AVF after T12 vertebral giant cell tumor curettage. Eight months after the initial surgery, revision en bloc surgery was planned. Preoperative computed tomography angiography was performed for vascularity assessment, which incidentally revealed a large paravertebral early-enhanced venous sac. High-flow AVF was confirmed through subsequent spinal angiography. Endovascular embolization was scheduled before the surgery to avoid massive blood loss. However, the AVF closed spontaneously 1 month after the spinal angiography. The plan was changed to preoperative embolization; subsequently, three-level en bloc spondylectomy was performed smoothly.

LESSONS

Iatrogenic AVF is possible, prompting investigation by vascular imaging when suspected. Embolization is a preferred treatment method when feasible. However, for iatrogenic etiology, the prothrombotic property of the contrast medium may induce the resolution. Multidisciplinary discussion can be very helpful before aggressive spinal surgery.

Reliability and accuracy of time-resolved contrast-enhanced magnetic resonance angiography in hypervascular spinal metastases prior embolization

OBJECTIVES

Preoperative embolization of hypervascular spinal metastases (HSM) is efficient to reduce perioperative bleeding. However, intra-arterial digital subtraction angiography (IA-DSA) must confirm the hypervascular nature and rule out spinal cord arterial feeders. This study aimed to evaluate the reliability and accuracy of time-resolved contrast-enhanced magnetic resonance angiography (TR-CE-MRA) in assessing HSM prior to embolization.

METHODS

All consecutive patients referred for preoperative embolization of an HSM were prospectively included. TR-CE-MRA sequences and selective IA-DSA were performed prior to embolization. Two readers independently reviewed imaging data to grade tumor vascularity (using a 3-grade and a dichotomized "yes vs no" scale) and identify the arterial supply of the spinal cord. Interobserver and intermodality agreements were estimated using kappa statistics.

RESULTS

Thirty patients included between 2016 and 2019 were assessed for 55 levels. Interobserver agreement was moderate (κ = 0.52; 95% CI [0.09-0.81]) for TR-CE-MRA. Intermodality agreement between TR-CE-MRA and IA-DSA was good (κ = 0.74; 95% CI [0.37-1.00]). TR-CE-MRA had a sensitivity of 97.9%, a specificity of 71.4%, a positive predictive value of 95.9%, a negative predictive value of 83.3%, and an overall accuracy of 94.6%, for differentiating hypervascular from non-hypervascular SM. The arterial supply of the spine was assessable in 2/30 (6.7%) cases with no interobserver agreement (κ < 0).

CONCLUSIONS

TR-CE-MRA can reliably differentiate hypervascular from non-hypervascular SM and thereby avoid futile IA-DSAs. However, TR-CE-MRA was not able to evaluate the vascular supply of the spinal cord at the target levels, thus limiting its scope as a pretherapeutic assessment tool.

KEY POINTS

• TR-CE-MRA aids in distinguishing hypervascular from non-hypervascular spinal metastases. • TR-CE-MRA could avoid one-quarter of patients referred for HSM embolization to undergo futile conventional angiography. • TR-CE-MRA's spatial resolution is insufficient to replace IA-DSA in the pretherapeutic assessment of the spinal cord vascular anatomy.

Advanced Imaging in Musculoskeletal Oncology: Moving Away From RECIST and Embracing Advanced Bone and Soft Tissue Tumor Imaging (ABASTI)-Part II-Novel Functional Imaging Techniques

Functional imaging can add valuable information to conventional imaging in the settings of tumor characterization and treatment response assessment. Traditional response criteria rely primarily on physical measurements, while functional imaging can potentially give a more comprehensive evaluation of oncological status. The second part of this review article discusses advanced imaging techniques such as susceptibility-weighted imaging, tumor-associated macrophage imaging, diffusion-weighted imaging, perfusion-weighted imaging, Dixon imaging, whole-body magnetic resonance imaging, whole-body low-dose dual energy computed tomography with virtual noncalcium technique, and ultrasound elastography.