Radiolabeled Somatostatin Receptor Antagonist Versus Agonist for Peptide Receptor Radionuclide Therapy in Patients with Therapy-Resistant Meningioma: PROMENADE Phase 0 Study

Our primary aim was to compare the therapeutic index (tumor-to-bone marrow and tumor-to-kidney absorbed-dose ratios) of the new radiolabeled somatostatin receptor antagonist [177Lu]Lu-DOTA-JR11 with the established radiolabeled somatostatin receptor agonist [177Lu]Lu-DOTATOC in the same patients with progressive, standard therapy-refractory meningioma. Methods: In this prospective, single-center, open-label phase 0 study (NCT04997317), 6 consecutive patients were included: 3 men and 3 women (mean age, 63.5 y). Patients received 6.9-7.3 GBq (standard injected radioactivity) of [177Lu]Lu-DOTATOC followed by 3.3-4.9 GBq (2 GBq/m2 × body surface area) of [177Lu]Lu-DOTA-JR11 at an interval of 10 ± 1 wk. In total, 1 [177Lu]Lu-DOTATOC and 2-3 [177Lu]Lu-DOTA-JR11 treatment cycles were performed. Quantitative SPECT/CT was done at approximately 24, 48, and 168 h after injection of both radiopharmaceuticals to calculate meningioma and organ absorbed doses as well as tumor-to-organ absorbed-dose ratios (3-dimensional segmentation approach for meningioma, kidneys, liver, bone marrow, and spleen). Results: The median of the meningioma absorbed dose of 1 treatment cycle was 3.4 Gy (range, 0.8-10.2 Gy) for [177Lu]Lu-DOTATOC and 11.5 Gy (range, 4.7-22.7 Gy) for [177Lu]Lu-DOTA-JR11. The median bone marrow and kidney absorbed doses after 1 treatment cycle were 0.11 Gy (range, 0.05-0.17 Gy) and 2.7 Gy (range, 1.3-5.3 Gy) for [177Lu]Lu-DOTATOC and 0.29 Gy (range, 0.16-0.39 Gy) and 3.3 Gy (range, 1.6-5.9 Gy) for [177Lu]Lu-DOTA-JR11, resulting in a 1.4 (range, 0.9-1.9) times higher median tumor-to-bone marrow absorbed-dose ratio and a 2.9 (range, 2.0-4.8) times higher median tumor-to-kidney absorbed-dose ratio with [177Lu]Lu-DOTA-JR11. According to the Common Terminology Criteria for Adverse Events version 5.0, 2 patients developed reversible grade 2 lymphopenia after 1 cycle of [177Lu]Lu-DOTATOC. Afterward, 2 patients developed reversible grade 3 lymphopenia and 1 patient developed reversible grade 3 lymphopenia and neutropenia after 2-3 cycles of [177Lu]Lu-DOTA-JR11. No grade 4 or 5 adverse events were observed at 15 mo or more after the start of therapy. The disease control rate was 83% (95% CI, 53%-100%) at 12 mo or more after inclusion. Conclusion: Treatment with 1 cycle of [177Lu]Lu-DOTA-JR11 showed 2.2-5.7 times higher meningioma absorbed doses and a favorable therapeutic index compared with [177Lu]Lu-DOTATOC after injection of 1.4-2.1 times lower activities. The first efficacy results demonstrated a high disease control rate with an acceptable safety profile in the standard therapy for refractory meningioma patients. Therefore, larger studies with [177Lu]Lu-DOTA-JR11 are warranted in meningioma patients.

49-year-old woman • headache and neck pain radiating to ears and eyes • severe hypertension • Dx?

► headache and neck pain radiating to ears and eyes ► severe hypertension.

Impact of Very Small Aneurysm Size and Anterior Communicating Segment Location on Outcome after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Very small anterior communicating artery aneurysms (vsACoA) of <5 mm in size are detected in a considerable number of patients with aneurysmal subarachnoid hemorrhage (aSAH). Single-center studies report that vsACoA harbor particular risks when treated.

OBJECTIVE

To assess the clinical and radiological outcome(s) of patients with aSAH diagnosed with vsACoA after aneurysm treatment and at discharge.

METHODS

Information on n = 1868 patients was collected in the Swiss Subarachnoid Hemorrhage Outcome Study registry between 2009 and 2014. The presence of a new focal neurological deficit at discharge, functional status (modified Rankin scale), mortality rates, and procedural complications (in-hospital rebleeding and presence of a new stroke on computed tomography) was assessed for vsACoA and compared with the results observed for aneurysms in other locations and with diameters of 5 to 25 mm.

RESULTS

This study analyzed n = 1258 patients with aSAH, n = 439 of which had a documented ruptured ACoA. ACoA location was found in 38% (n = 144/384) of all very small ruptured aneurysms. A higher in-hospital bleeding rate was found in vsACoA compared with non-ACoA locations (2.8 vs 2.1%), especially when endovascularly treated (2.1% vs 0.5%). In multivariate analysis, aneurysm size of 5 to 25 mm, and not ACoA location, was an independent risk factor for a new focal neurological deficit and a higher modified Rankin scale at discharge. Neither very small aneurysm size nor ACoA location was associated with higher mortality rates at discharge or the occurrence of a peri-interventional stroke.

CONCLUSION

Very small ruptured ACoA have a higher in-hospital rebleeding rate but are not associated with worse morbidity or mortality.

Effective Dose Measurements of the Latest-Generation Angiographic System in Patients with Acute Stroke: A Comparison with the Newest Multidetector CT Generation

BACKGROUND AND PURPOSE

Patients with acute ischemic stroke are increasingly triaged with one-stop management approaches, resulting in baseline imaging with a flat detector CT scanner. This study aimed to estimate the effective dose to a patient of a novel cervical and intracranial flat detector CT angiography and a flat detector CT perfusion protocol and to compare it with the effective dose of analogous multidetector row CT protocols.

MATERIALS AND METHODS

We estimated the effective dose to the patient according to the International Commission on Radiological Protection 103 using an anthropomorphic phantom with metal oxide semiconductor field effect transistor dosimeters. Placement was according to the organ map provided by the phantom manufacturer. We used 100 measurement points within the phantom, and 18 metal oxide semiconductor field effect transistor dosimeters were placed on the surface of the phantom. All protocols followed the manufacturer's specifications, and patient positioning and collimation were performed as in routine clinical practice. Measurements were obtained on the latest-generation angiography and multidetector row CT systems with identical placement of the metal oxide semiconductor field effect transistor dosimeters.

RESULTS

The estimated effective doses of the investigated perfusion protocols were 4.52 mSv (flat detector CT perfusion without collimation), 2.88 mSv (flat detector CT perfusion with collimation), and 2.17 mSv (multidetector row CT perfusion). A novel protocol called portrait flat detector CT angiography that has a z-axis coverage area comparable with that of multidetector row CT angiography had an estimated effective dose of 0.91 mSv, while the dose from multidetector row CT was 1.35 mSv.

CONCLUSIONS

The estimated effective dose to the patient for flat detector CT perfusion and angiography on a modern biplane angiography system does not deviate substantially from that of analogous multidetector row CT protocols.

Quantifying the Effects of Structured Reporting on Report Turnaround Times and Proofreading Workload in Neuroradiology

RATIONALE AND OBJECTIVES

To assess the effects of a change from free text reporting to structured reporting on resident reports, the proofreading workload and report turnaround times in the neuroradiology daily routine.

MATERIALS AND METHODS

Our neuroradiology section introduced structured reporting templates in July 2019. Reports dictated by residents during dayshifts from January 2019 to March 2020 were retrospectively assessed using quantitative parameters from report comparison. Through automatic analysis of text-string differences between report states (i.e. draft, preliminary and final report), Jaccard similarities and edit distances of reports following read-out sessions as well as after report sign-off were calculated. Furthermore, turnaround times until preliminary and final report availability to clinicians were investigated. Parameters were visualized as trending line graphs and statistically compared between reporting standards.

RESULTS

Three thousand five hundred thirty-eight reports were included into analysis. Mean Jaccard similarity of resident drafts and staff-reviewed final reports increased from 0.53 ± 0.37 to 0.79 ± 0.22 after the introduction of structured reporting (p < .001). Both mean overall edits on draft reports by residents following read-out sessions (0.30 ± 0.45 vs. 0.09 ± 0.29; p < .001) and by staff radiologists during report sign-off (0.17 ± 0.28 vs. 0.12 ± 0.23, p < .001) decreased. With structured reporting, mean turnaround time until preliminary report availability to clinicians decreased by 20.7 minutes (246.9 ± 207.0 vs. 226.2 ± 224.9; p < .001). Similarly, final reports were available 35.0 minutes faster on average (558.05 ± 15.1 vs. 523.0 ± 497.3; p = .002).

CONCLUSION

Structured reporting is beneficial in the neuroradiology daily routine, as resident drafts require fewer edits in the report review process. This reduction in proofreading workload is likely responsible for lower report turnaround times.

Utilization of Artificial Intelligence-based Intracranial Hemorrhage Detection on Emergent Noncontrast CT Images in Clinical Workflow

Authors implemented an artificial intelligence (AI)-based detection tool for intracranial hemorrhage (ICH) on noncontrast CT images into an emergent workflow, evaluated its diagnostic performance, and assessed clinical workflow metrics compared with pre-AI implementation. The finalized radiology report constituted the ground truth for the analysis, and CT examinations (n = 4450) before and after implementation were retrieved using various keywords for ICH. Diagnostic performance was assessed, and mean values with their respective 95% CIs were reported to compare workflow metrics (report turnaround time, communication time of a finding, consultation time of another specialty, and turnaround time in the emergency department). Although practicable diagnostic performance was observed for overall ICH detection with 93.0% diagnostic accuracy, 87.2% sensitivity, and 97.8% negative predictive value, the tool yielded lower detection rates for specific subtypes of ICH (eg, 69.2% [74 of 107] for subdural hemorrhage and 77.4% [24 of 31] for acute subarachnoid hemorrhage). Common false-positive findings included postoperative and postischemic defects (23.6%, 37 of 157), artifacts (19.7%, 31 of 157), and tumors (15.3%, 24 of 157). Although workflow metrics such as communicating a critical finding (70 minutes [95% CI: 54, 85] vs 63 minutes [95% CI: 55, 71]) were on average reduced after implementation, future efforts are necessary to streamline the workflow all along the workflow chain. It is crucial to define a clear framework and recognize limitations as AI tools are only as reliable as the environment in which they are deployed. Keywords: CT, CNS, Stroke, Diagnosis, Classification, Application Domain © RSNA, 2022.

Complication rates of percutaneous brachial artery puncture: effect of live ultrasound guidance

Purpose

The current literature on the use of brachial artery access is controversial. Some studies found increased puncture site complications. Others found no higher complication rates than in patients with femoral or radial access. The purpose of this study was to determine the impact of ultrasound (US)-guidance on access site complications.

Materials and methods

This is a single-center retrospective study of all consecutive patients with brachial arterial access for interventional procedures. Complications were classified into minor complications (conservative treatment only) and major complications (requiring surgical intervention). The brachial artery was cannulated in the antecubital fossa under US-guidance. After the intervention, manual compression or closure devices, both followed by a compression bandage for 3 h, either achieved hemostasis.

Results

Seventy-five procedures in seventy-one patients were performed in the study period using brachial access. Access was successful in all cases (100%). Procedures in different vascular territories were performed: neurovascular (10/13.5%), upper extremity (32/43.2%), visceral (20/27.0%), and lower extremity (12/16.3%). Sheath size ranged from 3.2F to 8F (mean: 5F). Closure devices were used in 17 cases (22.7%). In total, six complications were observed (8.0%), four minor complications (5.3%, mostly puncture site hematomas), and two major complications, that needed surgical treatment (2.7%). No brachial artery thrombosis or upper extremity ischemia occurred.

Conclusion

Exclusive use of US-guidance resulted in a low risk of brachial artery access site complications in our study compared to the literature. US-guidance has been proven to reduce the risk of access site complications in several studies in femoral access. In addition, brachial artery access yields a high technical success rate and requires no additional injection of spasmolytic medication. Sheath size was the single significant predictor for complications.

Transcarotid artery revascularization (TCAR) – first experience

Objective

In transcarotid artery revascularization (TCAR) the carotid stent used to treat carotid artery stenosis is introduced via a cut-down to the common carotid artery (CCA). Stent placement is performed during flow reversal using an external shunt to the femoral vein. The advantages compared to transfemoral carotid stenting are that the risks of embolization from the aortic arch and origin of the arch vessels are avoided and that clamping of the common carotid artery allows complete flow-reversal during stent placement. TCAR was developed in 2015 and is extensively used predominately in the USA. To our knowledge, TCAR has until now not been used in Switzerland. We present our first experience with TCAR.

Methods

Retrospective analysis of consecutive patients.

Results

We treated 4 patients with TCAR from Dec 2019 to May 2020. All patients were male, median age was 66y. All had high-grade internal carotid artery (ICA) stenosis (3 asymptomatic, 1 symptomatic). All procedures were performed in a hybrid operation room. Technical success was achieved in 3 patients. In these patients there was no peri-interventional stroke or TIA and duplex sonography 6 months postoperatively showed a patent stent without restenosis. In the fourth patient previous attempted transfemoral stenting for symptomatic ICA-stenosis had failed because of a very tortuous CCA. During TCAR, puncture of the CCA was difficult because of atherosclerotic thickening of the vessel wall, furthermore the tip of the guidewire for insertion of the dedicated sheath into the CCA needed to be placed in the CCA rather than in the external carotid artery (ECA) because of ECA occlusion. This led to inadvertent crossing of the stenosis with the guide wire. The procedure was abolished and converted to a conventional carotid endarterectomy. The patient had a perioperative minor stroke with signs of embolization into branches of the medial cerebral artery. He underwent transfemoral intracranial thrombectomy and eventually recovered with only minor deficits.

Conclusion

Our first experience with TCAR confirmed that patient selection is important: A combination of atherosclerotic disease of the CCA and occlusion of the ECA, both in themselves only relative contraindications to TCAR, led to technical failure and perioperative stroke. With good patient selection TCAR could be performed safely.

Endovascular Thrombectomy of Calcified Emboli in Acute Ischemic Stroke: A Multicenter Study

BACKGROUND AND PURPOSE

Large intracranial vessel occlusion due to calcified emboli is a rare cause of major stroke. We assessed the prevalence, imaging appearance, the effectiveness of mechanical thrombectomy, and clinical outcome of patients with large-vessel occlusion due to calcified emboli.

MATERIALS AND METHODS

We performed a retrospective analysis of clinical and procedural data of consecutive patients who underwent mechanical thrombectomy due to calcified emboli in 7 European stroke centers.

RESULTS

We screened 2969 patients, and 40 patients matched the inclusion criteria, accounting for a prevalence of 1.3%. The mean maximal density of the thrombus was 327 HU (range, 150-1200 HU), and the mean thrombus length was 9.2 mm (range, 4-20 mm). Four patients had multiple calcified emboli, and 2 patients had an embolic event during an endovascular intervention. A modified TICI score of ≥2b was achieved in 57.5% (23/40), with minimal-to-no reperfusion (modified TICI 0-1) in 32.5% (13/40) and incomplete reperfusion (modified TICI 2a) in 10% (4/40). Excellent outcome (mRS 0-1) was achieved in only 20.6%, functional independence (mRS 0-2) in 26.5% and 90-day mortality was 55.9%.

CONCLUSIONS

Acute ischemic stroke with large-vessel occlusion due to calcified emboli is a rare entity in patients undergoing thrombectomy, with considerably worse angiographic outcome and a higher mortality compared with patients with noncalcified thrombi. Good functional recovery at 3 months can still be achieved in about a quarter of patients.

Intra-Arterial Verapamil Treatment in Oral Therapy-Refractory Reversible Cerebral Vasoconstriction Syndrome

Reversible vasoconstriction syndrome is a complex of clinical symptoms and angiographic findings, which, while having a mostly benign clinical course, has clinical and imaging overlap with more serious disorders such as vasculitis and aneurysmal SAH and itself includes a minority of patients with fulminant vasoconstriction resulting in severe intracranial complications. Endovascular options for patients with refractory reversible cerebral vasoconstriction syndrome include intra-arterial vasodilator infusion similar to therapy for patients with vasospasm after SAH. To date, only case reports and 1 small series have discussed the utility of intra-arterial vasodilators for the treatment of reversible cerebral vasoconstriction syndrome. We report an additional series of 11 medically refractory cases of presumed or proved reversible cerebral vasoconstriction syndrome successfully treated with intra-arterial verapamil infusion. Furthermore, we propose that the reversal of vasoconstriction, as seen on angiography, could fulfill a diagnostic criterion.

Correction to: Ruptured PICA aneurysms: presentation and treatment outcomes compared to other posterior circulation aneurysms. A Swiss SOS study

Incorrect authorgroup and authorname.

Ruptured PICA aneurysms: presentation and treatment outcomes compared to other posterior circulation aneurysms. A Swiss SOS study

BACKGROUND AND PURPOSE

Aneurysms of the posterior inferior cerebellar artery (PICA) are relatively uncommon and evidence is sparse about patients presenting with ruptured PICA aneurysms. We performed an analysis of the Swiss SOS national registry to describe clinical presentation, treatment pattern, and neurological outcome of patients with ruptured PICA aneurysms compared with other ruptured posterior circulation (PC) aneurysms.

METHODS

This was a retrospective analysis of anonymized data from the Swiss SOS registry (Swiss Study on Aneurysmal Subarachnoid Hemorrhage; 2009-2014). Patients with ruptured PC aneurysms were subdivided into a PICA and non-PICA group. Clinical, radiological, and treatment-related variables were identified, and their impact on the neurological outcome was determined in terms of modified Rankin score at discharge and at 1 year of follow-up for the two groups.

RESULTS

Data from 1864 aneurysmal subarachnoid hemorrhage patients were reviewed. There were 264 patients with a ruptured PC aneurysm. Seventy-four PICA aneurysms represented 28% of the series; clinical and radiological characteristics at admission were comparable between the PICA and non-PICA group. Surgical treatment was accomplished in 28% of patients in the PICA group and in the 4.8% of patients in the non-PICA group. No statistically significant difference was found between the two groups in terms of complications after treatment. Hydrocephalus requiring definitive shunt was needed in 21.6% of PICA patients (p = 0.6); cranial nerve deficit was present in average a quarter of the patients in both PICA and non-PICA group with no statistical difference (p = 0.3). A more favorable outcome (66.2%) was reported in the PICA group at discharge (p < 0.05) but this difference faded over time with a similar neurological outcome at 1-year follow-up (p = 0.09) between both PICA and non-PICA group. The Kaplan-Meyer estimation showed no significant difference in the mortality rate between both groups (p = 0.08).

CONCLUSIONS

In the present study, patients with ruptured PICA aneurysms had a favorable neurological outcome in more than two thirds of cases, similar to patients with other ruptured PC aneurysms. Surgical treatment remains a valid option in a third of cases with ruptured PICA aneurysms.

Correction to: Ruptured posterior circulation aneurysms: epidemiology, patterns of care, and outcomes from the Swiss SOS national registry

The name of Roy Thomas Daniel was incorrectly captured in the original manuscript.

Ruptured posterior circulation aneurysms: epidemiology, patterns of care, and outcomes from the Swiss SOS national registry

BACKGROUND

The treatment of ruptured posterior circulation aneurysms remains challenging despite progresses in the endovascular and neurosurgical techniques.

OBJECTIVE

To provide epidemiological characterization of subjects presenting with ruptured posterior circulation aneurysms in Switzerland and thereby assessing the treatment patterns and neurological outcomes.

METHODS

This is a retrospective analysis of the Swiss SOS registry for patients with aneurysmal subarachnoid hemorrhage. Patients were divided in 3 groups (upper, lower, and middle third) according to aneurysm location. Clinical, radiological, and treatment-related variables were identified and their impact on the neurological outcome was determined.

RESULTS

From 2009 to 2014, we included 264 patients with ruptured posterior circulation aneurysms. Endovascular occlusion was the most common treatment in all 3 groups (72% in the upper third, 68% in the middle third, and 58.8% in the lower third). Surgical treatment was performed in 11.3%. Favorable outcome (mRS ≤ 3) was found in 56% at discharge and 65.7% at 1 year. No significant difference in the neurological outcome were found among the three groups, in terms of mRS at discharge (p = 0.20) and at 1 year (p = 0.18). High WFNS grade, high Fisher grade at presentation, and rebleeding before aneurysm occlusion (p = 0.001) were all correlated with the risk of unfavorable neurological outcome (or death) at discharge and at 1 year.

CONCLUSIONS

In this study, endovascular occlusion was the principal treatment, with a favorable outcome for two-thirds of patients at discharge and at long term. These results are similar to high volume neurovascular centers worldwide, reflecting the importance of centralized care at specialized neurovascular centers.

Comparison of Pipeline Embolization Device Sizing Based on Conventional 2D Measurements and Virtual Simulation Using the Sim&Size Software: An Agreement Study

BACKGROUND AND PURPOSE

The Sim&Size software simulates case-specific intraluminal Pipeline Embolization Device behavior, wall apposition, and device length in real-time on the basis of rotational angiography DICOM data. The purpose of this multicenter study was to evaluate whether preimplantation device simulation with the Sim&Size software results in selection of different device dimensions than manual sizing.

MATERIALS AND METHODS

In a multicenter cohort of 74 patients undergoing aneurysm treatment with the Pipeline Embolization Device, we compared apparent optimal device dimensions determined by neurointerventionalists with considerable Pipeline Embolization Device experience based on manual 2D measurements taken from rotational angiography with computed optimal dimensions determined by Sim&Size experts blinded to the neurointerventionalists' decision. Agreement between manually determined and computed optimal dimensions was evaluated with the Cohen κ. The significance of the difference was analyzed with the Wilcoxon signed rank test.

RESULTS

The agreement index between manual selection and computed optimal dimensions was low (κ for diameter = 0.219; κ for length = 0.149, P < .01). Computed optimal device lengths were significantly shorter (median, 14 versus 16 mm, T = 402, r = -0.28, P < .01). No significant difference was observed for device diameters.

CONCLUSIONS

Low agreement between manually determined and computed optimal device dimensions is not proof, per se, that virtual simulation performs better than manual selection. Nevertheless, it ultimately reflects the potential for optimization of the device-sizing process, and use of the Sim&Size software reduces, in particular, device length. Nevertheless, further evaluation is required to clarify the impact of device-dimension modifications on outcome.

Factors associated with clinical and radiological status on admission in patients with aneurysmal subarachnoid hemorrhage

Grading scales yield objective measure of the severity of aneurysmal subarachnoid hemorrhage and serve as to guide treatment decisions and for prognostication. The purpose of this cohort study was to determine what factors govern a patient's disease-specific admission scores in a representative Central European cohort. The Swiss Study of Subarachnoid Hemorrhage includes anonymized data from all tertiary referral centers serving subarachnoid hemorrhage patients in Switzerland. The 2009-2014 dataset was used to evaluate the impact of patient and aneurysm characteristics on the patients' status at admission using descriptive and multivariate regression analysis. The primary/co-primary endpoints were the GCS and the WFNS grade. The secondary endpoints were the Fisher grade, the presence of a thick cisternal or ventricular clot, the presence of a new focal neurological deficit or cranial nerve palsy, and the patient's intubation status. In our cohort of 1787 consecutive patients, increasing patient age by 10 years and low pre-ictal functional status (mRS 3-5) were inversely correlated with "high" GCS score (GCS ≥ 13) (OR 0.91, 95% CI 0.84-0.97 and OR 0.67, 95% CI 0.31-1.46), "low" WFNS grade (grade VI-V) (OR 1.21, 95% CI 1.04-1.20 and OR 1.47, 95% CI 0.66-3.27), and high Fisher grade (grade III-IV) (OR 1.08, 95% CI 1.00-1.17 and OR 1.54, 95% CI 0.55-4.32). Other independent predictors for the patients' clinical and radiological condition at admission were the ruptured aneurysms' location and its size. In sum, chronological age and pre-ictal functional status, as well as the ruptured aneurysm's location and size, determine the patients' clinical and radiological condition at admission to the tertiary referral hospital.

In Vivo Characterization of Carotid Neointimal Hyperplasia by use of Optical Coherence Tomography: Before and After Cutting Balloon Angioplasty

Optical coherence tomography (OCT) is a modern intravascular imaging modality that has the capability to provide detailed, in vivo characterization of the arterial wall and atherosclerotic plaque. The current understanding of the appearance of atherosclerotic plaque via OCT is largely based on coronary arterial studies where OCT information has been employed to guide therapeutic management and permits the immediate evaluation of percutaneous intervention. The clinical success of OCT in the coronary arteries has laid the foundation for investigation of the carotid artery and thus, stroke risk assessment. We report the novel use of OCT for tissue characterization of severe stenosis subsequent to carotid artery stenting (CAS), both before and after treatment with cutting balloon angioplasty.

Republished: Society for Neuroscience in Anesthesiology and Critical Care expert consensus statement: Anesthetic management of endovascular treatment for acute ischemic stroke

Literature on the anesthetic management of endovascular treatment of acute ischemic stroke (AIS) is limited. Anesthetic management during these procedures is still mostly dependent on individual or institutional preferences. Thus, the Society of Neuroscience in Anesthesiology and Critical Care (SNACC) created a task force to provide expert consensus recommendations on anesthetic management of endovascular treatment of AIS. The task force conducted a systematic literature review (up to August 2012). Because of the limited number of research articles relating to this subject, the task force solicited opinions from experts in this area. The task force created a draft consensus statement based on the available data. Classes of recommendations and levels of evidence were assigned to articles specifically addressing anesthetic management during endovascular treatment of stroke using the standard American Heart Association evidence rating scheme. The draft consensus statement was reviewed by the Task Force, SNACC Executive Committee and representatives of Society of NeuroInterventional Surgery (SNIS) and Neurocritical Care Society (NCS) reaching consensus on the final document. For this consensus statement the anesthetic management of endovascular treatment of AIS was subdivided into 12 topics. Each topic includes a summary of available data followed by recommendations. This consensus statement is intended for use by individuals involved in the care of patients with acute ischemic stroke, such as anesthesiologists, interventional neuroradiologists, neurologists, neurointensivists and neurosurgeons.

Abstract WP86: Anterior Communicating Artery Cerebral Aneurysms, 10-year Treatment Experience at a Tertiary Referral Medical Center: Large Prevalence of Ruptured Small Aneurysms

Purpose To determine patient characteristics and size distribution among ruptured and unruptured anterior communicating artery (AComA) aneurysms less than 7 mm treated with coiling or clipping in a 10-year time period at a tertiary referral medical center. A secondary objective is comparison of institutional data to published ISUIA data of 0% 5-year cumulative rupture risk for anterior circulation aneurysms < 7 mm.

Materials & Methods We retrospectively reviewed AComA aneurysm characteristics in all patients who were treated with coiling or clipping from December 2002 until June 2012. Aneurysm location and maximum sac diameter were recorded utilizing catheter angiography or computed tomography angiography.

Results In our series, 180 AComA aneurysms were treated from 12/2002 to 6/2012. 123 (68.0%) AComA aneurysms were treated in the setting of nontraumatic subarachnoid hemorrhage (SAH) while 57 (32.0%) were treated electively. Table 1 shows the characteristics of the AComA aneurysms in our series. Table 2 shows the size breakdown of ruptured and unruptured AComA aneurysms.

Table 1. AComA Aneurysm Characteristics.

Table 2. AComA Aneurysm Size Breakdown

Conclusion Among ruptured AComA aneurysms, 61.0% had a maximum diameter < 7 mm, while 35.0% were < 5 mm, which argues against the reported low risk of rupture in aneurysms < 7 mm based on the ISUIA trial. Further studies are recommended to correlate risk of rupture with such factors as personal or family history of subarachnoid hemorrhage, medical comorbidities, and documented growth of aneurysm.

Abstract WMP2: Computed Tomography or Magnetic Resonance Perfusion Imaging Benefits Selection of Acute Ischemic Stroke Patients for Endovascular Treatment

Background: Perfusion imaging to guide selection of patients for endovascular treatment of acute ischemic stroke (AIS) remains controversial. CT and MR perfusion have been performed at our institution during evaluation of AIS in order to triage patients who are more likely to benefit from endovascular therapy. The purpose of this study was to compare the clinical outcome between patients who did and did not receive advanced perfusion imaging prior to treatment.

Methods: From April 2004 to July 2012, 330 patients with large vessel AIS were retrospectively reviewed and divided into three cohorts: 1) perfusion imaging followed by mechanical thrombectomy (MT) and/or intra-arterial thrombolysis (IAT) (n= 98), 2) no perfusion imaging followed by MT and/or IAT (n= 191) and 3) perfusion imaging without endovascular treatment (n = 41). Cohorts were compared based on neurologic improvement (≥4 point change in NIHSS), successful revascularization (TIMI 2-3), symptomatic intracranial hemorrhage (sICH), discharge modified rankin score (mRS) ≤3 and in-hospital mortality. Multivariate regression was performed to determine the predictive value of perfusion imaging prior to endovascular therapy.

Results: Of 289 treated patients, mean age was 67 and median initial NIHSS was 17. The treated groups were matched in baseline characteristics and had no difference in the outcomes of successful revascularization, discharge mRS≤3 and improvement in NIHSS. However, 10 of 98 with perfusion imaging expired compared to 48 of 191 without perfusion (p=0.01). Logistic regression showed patients who had perfusion imaging prior to endovascular therapy were less likely to die during hospitalization (OR = 0.267; 95% CI = 0.170, 0.364) or to develop sICH (OR = 0.269; CI = 0.182, 0.356) Other predictors of mortality included advanced age (OR= 1.08; CI = 1.04, 1.13) and high initial NIHSS (OR = 1.14; CI = 1.09, 1.19). There was no mortality difference between treated and untreated cohorts.

Conclusion: Patients who underwent CT or MR perfusion imaging prior to neurointervention for AIS were significantly less likely to suffer sICH or in-hospital mortality, providing evidence for the positive role of advanced imaging in selecting patients for endovascular treatment.

Standard of practice: endovascular treatment of intracranial atherosclerosis

BACKGROUND

Symptomatic intracranial atherosclerotic disease (ICAD) worldwide represents one of the most prevalent causes of stroke. When severe, studies show that it has a very high risk for recurrent stroke, highlighting the need for effective preventative strategies. The mainstay of treatment has been medical therapy and is of critical importance in all patients with this disease. Endovascular therapy is also a possible therapeutic option but much remains to be defined in terms of best techniques and patient selection. This guideline will serve as recommendations for diagnosis and endovascular treatment of patients with ICAD.

METHODS

A literature review was performed to extract published literature regarding ICAD, published from 2000 to 2011. Evidence was evaluated and classified according to American Heart Association (AHA)/American Stroke Association standard. Recommendations are made based on available evidence assessed by the Standards Committee of the Society of NeuroInterventional Surgery. The assessment was based on guidelines for evidence based medicine proposed by the American Academy of Neurology (AAN), the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM).

RESULTS

59 publications were identified. The SAMMPRIS study is the only prospective, randomized, controlled trial available and is given an AHA level B designation, AAN class II and CEBM level 1b. The Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial arteries (SSYLVIA) trial was a prospective, non-randomized study with the outcome assessment made by a non-operator study neurologist, allowing an AHA level B, AAN class III and CEBM level 2. The remaining studies were uncontrolled or did not have objective outcome measurement, and are thus classified as AHA level C, AAN class IV and CEBM level 4.

CONCLUSION

Medical management with combination aspirin and clopidogrel for 3 months and aggressive risk factor modification is the firstline therapy for patients with symptomatic ICAD. Endovascular angioplasty with or without stenting is a possible therapeutic option for selected patients with symptomatic ICAD. Further studies are necessary to define appropriate patient selection and the best therapeutic approach for various subsets of patients.

Invasive interventional management of post-hemorrhagic cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage

Current clinical practice standards are addressed for the invasive interventional management of post-hemorrhagic cerebral vasospasm (PHCV) in patients with aneurysmal subarachnoid hemorrhage. The conclusions, based on an assessment by the Standards Committee of the Society of Neurointerventional Surgery, included a critical review of the literature using guidelines for evidence based medicine proposed by the Stroke Council of the American Heart Association and the University of Oxford, Centre for Evidence Based Medicine. Specifically examined were the safety and efficacy of established invasive interventional therapies, including transluminal balloon angioplasty (TBA) and intra-arterial vasodilator infusion therapy (IAVT). The assessment shows that these invasive interventional therapies may be beneficial and may be considered for PHCV-that is, symptomatic with cerebral ischemia and refractory to maximal medical management. As outlined in this document, IAVT may be beneficial for the management of PHCV involving the proximal and/or distal intradural cerebral circulation. TBA may be beneficial for the management of PHCV that involves the proximal intradural cerebral circulation. The assessment shows that for the indications described above, TBA and IAVT are classified as Class IIb, Level B interventions according to the American Heart Association guidelines, and Level 4, Grade C interventions according to the University of Oxford Centre for Evidence Based Medicine guidelines.

Abstract 3274: Early Symptom Onset to Arterial Puncture Time in the Endovascular Management of Acute Ischemic Stroke Predicts Successful Revascularization

Background: As is seen in the early door-to-needle times of intravenous thrombolysis in the treatment of acute ischemic stroke (AIS), prior endovascular management trials have demonstrated early revascularization can lead to improved outcomes. We aimed to study the relationship of the time from acute stroke onset to the time of arterial groin puncture (OTP) as a possible predictor of successful revascularization.

Methods: We retrospectively analyzed 149 patients who presented to our hospital with AIS and underwent emergent endovascular treatment from January 1, 2008 to March 31, 2011. Charts were reviewed for baseline characteristics, OTP times, and endovascular therapies employed. Primary outcomes included successful revascularization (TIMI 2 to 3 flow), improvement of baseline NIHSS ≥ 4, symptomatic ICH (increase of NIHSS ≥ 4), in-hospital mortality, and mRS two or less at discharge. We excluded patients with OTP times greater than eight hours to ensure consistency with approved usage of mechanical thrombectomy devices. Independent samples T-tests were performed to determine relationships of OTP with our primary outcomes.

Results: Of the 149 patients who underwent endovascular therapy, 120 had OTP times less than eight hours. Of these 120, 44% were male, median age was 73 years (range 17, 93), median baseline NIHSS was 18 (range 5, 28), 53% received intravenous tissue plasminogen activator (tPA), 69% received intra-arterial tPA, and mechanical thrombectomy was performed in 69%. Internal carotid artery occlusions were seen in 32% of patients, 50% had M1 segment occlusions, and only five patients had posterior circulation occlusions. Successful revascularization was achieved in 70% of interventions, 10% of patients had mRS ≤ 2 at discharge, symptomatic hemorrhage was 18%, and in-hospital mortality was 24%. Patients with TIMI 2 to 3 flow had significantly shorter mean OTP times (3.9 vs 4.5 hours; p=0.024). No significant associations of mean OTP times were found with symptomatic hemorrhage rate (4.4 vs 4.0; p=0.628), in-hospital mortality (4.0 vs 4.0; p=0.677), improvement in NIHSS (3.9 vs 4.2; p=0.283), or a mRS ≤ 2 at discharge (3.7 vs 4.1; p=0.185).

Conclusions: The recanalization rate in our study is comparable to prior endovascular trials. Patients with OTP times less than 3.9 hours were more likely to result in successful revascularization. Onset to groin puncture did not predict in-hospital mortality, symptomatic hemorrhage, or condition at discharge in our study. Further study is needed to determine if advanced perfusion imaging prior to intervention may impact treatment time and ultimately clinical outcome.

Abstract 3708: Safety and Efficacy of Antiplatelet Monotherapy (clopidogrel) in Stent Assisted Elective Coil Embolization of Cerebral Aneurysms

BACKGROUND AND PURPOSE: Thromboembolic events are the most common complication seen in elective coil embolization of cerebral aneurysms. Previous studies have shown that administration of oral clopidogrel and/or aspirin may lower the thromboembolic complication rate but little data exists regarding clinical outcome with the use of antiplatelet monotherapy in stent assisted elective aneurysm coil embolization.

Objectives: To assess the safety and efficacy of antiplatelet monotherapy (clopidogrel) in elective stent assisted coil embolization of cerebral aneurysms

MATERIALS AND METHODS: Retrospective chart review was performed in 94 consecutive patients who underwent endovascular treatments for elective coil embolization of cerebral aneurysms between 2008-2010. Thirty patients were included in this study who met the inclusion criteria of stent assisted coil embolization. All these patients received 75mg clopidogrel for one week prior to the procedure. Clopidogrel was continued post procedure for six to eight weeks. Primary outcome measure was peri-procedure and post-procedure symptomatic thromboembolic complications.

RESULTS The study included 23 females and 7 males with mean age 52.6 years.Twenty (66.7%) patients had anterior circulation aneurysms and 10 (33.3%) patients had posterior circulation aneurysms. Twenty (66.7%) patients were treated with Neuroform, 9 (30%) patients with Enterprise stent and 1 (3.3%) patient was treated with both Neuroform and Enterprise stent assisted coil embolization. One (3.3%) patient had an iatrogenic flow limiting vertebral artery dissection during embolization of vertebrobasilar artery aneurysm with no clinical deficit. The patient’s vertebral artery dissection was treated with 2 Wingspan stents and 1 Medtronic driver stents. Symptomatic thromboembolic complication was seen in 1 patient (3.3%) at discharge. The patient had a giant basilar tip aneurysm which was treated with stent assisted coil embolization. Postprocedure the patient had a right facial palsy with gaze deviation. The MRI was consistent with acute posterior circulation stroke. The patient was discharged home with a modified Rankin Scale <2. Follow up at six to eight weeks post procedure clinical data was available for 21 patients (73.3%). No delayed thromboembolic complication was observed in these patients at follow up visit.

CONCLUSION: Oral clopidogrel is safe and efficacious as an antiplatelet monotherapy during elective stent assisted coil embolization. Further multicenter prospective trials are warranted to evaluate safety and efficacy of clopidogrel as a monotherapy for elective stent assisted coil embolization.

Abstract 3456: Incidence of Vasospasm and Outcomes in Angiography-negative Perimesencephalic Subarachnoid Hemorrhage with and without Ventricular Extension

Background: Angiography negative perimesencephalic subarachnoid hemorrhage (SAH) is considered a relatively benign entity compared to aneurysmal SAH. However, some patients with angiography negative perimesencephalic subarachnoid hemorrhage with extension of hemorrhage beyond the perimesencephalic area are at increased risk for vasospasm. Here we present a series of 21 patients with angiography negative perimesencephalic pattern of SAH both with and without ventricular extension and describe their incidence of vasospasm and clinical outcomes.

Methods: Retrospective chart review was performed among patients who underwent invasive angiography from 8/2007-6/2010. Inclusion criteria were presenting clinical symptoms typical of SAH, computed tomography (CT) evidence of perimesencephalic SAH with or without ventricular extension, no recent trauma or stroke, and cerebral angiography negative for aneurysm or arteriovenous malformation. 21 patients, 8 men and 13 women, with a mean age of 55.1 years met these criteria. The presenting CTs were examined and a modified Fisher Grade assigned. The patients’ clinical course was reviewed for incidence and treatment of vasospasm. The patients’ discharge summaries were evaluated and each patient given a modified Rankin Scale score.

Results: The modified Fisher Scale score derived from the presenting CT was 1 for 29% (n=6), 2 for 5% (n=1), 3 for 19% (n=4), and 4 for 47% (n=10) of the patients. Amongst the 52% (n=11) of patients with intraventricular hemorrhage as defined by a modified Fisher Scale score of 2 or 4, 24% (n=5) developed angiographical evidence of vasospasm. 10% (n=2) of the patients required intra-arterial verapamil. 90% (n=9) of patients without intraventricular extension had good outcomes at discharge as defined by modified Rankin Scale score less than or equal to 2, while only 36% (n=4) of patients with angiography negative SAH with intraventricular extension had good outcomes.

Conclusions: Although angiography negative perimesencephalic SAH is considered to have less associated morbidity and mortality than aneurysmal perimesencephalic SAH, patients with extension of hemorrhage into the ventricles are at increased risk for vasospasm and poor functional outcomes.

Endovascular therapy of acute ischemic stroke: report of the Standards of Practice Committee of the Society of NeuroInterventional Surgery

OBJECTIVE

To summarize and classify the evidence for the use of endovascular techniques in the treatment of patients with acute ischemic stroke.

METHODS

Recommendations previously published by the American Heart Association (AHA) (Guidelines for the early management of adults with ischemic stroke (Circulation 2007) and Scientific statement indications for the performance of intracranial endovascular neurointerventional procedures (Circulation 2009)) were vetted and used as a foundation for the current process. Building on this foundation, a critical review of the literature was performed to evaluate evidence supporting the endovascular treatment of acute ischemic stroke. The assessment was based on guidelines for evidence based medicine proposed by the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Procedural safety, technical efficacy and impact on patient outcomes were specifically examined.

Comparison of brain MR images at 1.5T using BLADE and rectilinear techniques for patients who move during data acquisition

BACKGROUND AND PURPOSE

MR imaging of moving patients can be challenging and motion correction techniques have been proposed though some have associated new artifacts. The objective of this study was to semiquantitatively compare brain MR images of moving patients obtained at 1.5T by using partially radial and rectilinear acquisition techniques.

MATERIALS AND METHODS

FLAIR, T2-, T1-, and contrast-enhanced T1-weighted image sets of 25 patients (14-94 years) obtained by using BLADE (like PROPELLER, a partially radial acquisition) and rectilinear techniques in the same imaging session were compared by 2 neuroradiologists in terms of extent of the motion artifact, image quality, and lesion visibility. ICC between opinions of the evaluators was calculated.

RESULTS

Of the total of 70 image sets, the motion artifact was small in the partially radial images in 43 and in the rectilinear images in 13, and the opinions of the evaluators were discordant in the remaining 14 sets (ICC = 0.63, P < .05). The quality of partially radial images was higher for 36 sets versus 9 rectilinear sets, with disagreement between the 2 evaluators in the remaining 25 (ICC = 0.15, P < .05). Pathologic lesions were better characterized on 37 sets of partially radial images versus 13 sets of rectilinear images, and opinions of the evaluators differed in 20 sets (ICC = 0.90, P < .05). The neuroradiologists deemed 4 sets of rectilinear images nondiagnostic compared with only 1 set of radial images.

CONCLUSIONS

The data demonstrate that our application of BLADE sequences reduces the extent of motion artifacts in brain images of moving patients, improving image quality and lesion characterization.

Outcomes of intra-arterial thrombolytic treatment in acute ischemic stroke patients with a matched defect on diffusion and perfusion MR images

BACKGROUND

For acute ischemic stroke patients with matched defects on diffusion-perfusion imaging, the effects of reperfusion therapy remain poorly documented. The outcomes in a rare series of patients who had a matched defect and then underwent intra-arterial thrombolytic treatment (IAT) are reported.

METHODS

Medical record and MR image review between 1 January 1998 and 15 October 2008 revealed only eight acute ischemic stroke patients satisfying the atypical combination of both matched defect and IAT. Successful recanalization (SR), favorable clinical response (FCR) and symptomatic intracranial hemorrhage (SICH) were defined respectively as thrombolysis in cerebral infarction score ≥2 after IAT, discharge National Institutes of Health Stroke Scale (NIHSS) 0-1/≥8 point decrease from baseline and intracranial hemorrhage in infarct zone with ≥4 point increase in NIHSS Score within 24 h of IAT.

RESULTS

Median (range) baseline NIHSS score was 16.5 (6-22). Median (range) time delays from symptom onset to MRI and to IAT initiation were 200 (83-240) and 267.5 (160-360) min, respectively. Median (range) values of diffusion and perfusion lesion volumes were 119.5 (24-205) and 118 (18-207) ml. Out of eight patients, one (12.5%) achieved FCR, four (50%) had SICH and five (62.5%) died. Out of six patients with SR, one achieved FCR and four had SICH and died, and of two patients without SR, none had FCR or SICH and one died.

CONCLUSION

Our data on rare patients with matched defects who nevertheless had attempted rescue with IAT confirm a poor risk-benefit ratio generated by low favorable responses and high mortality rates, especially in large ischemic lesions.

Applications of time-resolved MR angiography

OBJECTIVE

The purpose of this essay is to describe the basic principles behind contrast-enhanced time-resolved MR angiography (MRA) performed with the time-resolved imaging with stochastic trajectories technique and to show examples of the versatile applications of this technique in the evaluation of pathologic conditions throughout the body.

CONCLUSION

Time-resolved MR angiography is a versatile technique for vascular imaging throughout the body. It can be used to answer a variety of clinical questions; to acquire diagnostically useful information, even about complicated vascular lesions; and to overcome many of the limitations of bolus-chase contrast-enhanced MR angiography. The technique is particularly useful when the arterial arrival time is uncertain, the patient is freely breathing, or contrast dynamics are critical to a diagnosis.

Extensive dural sinus thrombosis: successful recanalization with thrombolysis and a novel thrombectomy device

The author presents a novel endovascular treatment approach to extensive dural venous sinus thrombosis using the Penumbra clot aspiration system and local administration of recombinant tissue plasminogen activator. The clinical course, technical treatment aspects, and follow-up are described.

Evaluation of image quality of a 32-channel versus a 12-channel head coil at 1.5T for MR imaging of the brain

BACKGROUND AND PURPOSE

Multichannel phased-array head coils are undergoing exponential escalation of coil element numbers. While previous technical studies have found gains in SNR and spatial resolution with the addition of element coils, it remains to be determined how these gains affect clinical reading. The purpose of this clinical study was to determine if the SNR and spatial resolution characteristics of a 32-channel head coil result in improvements in perceived image quality and lesion evaluation.

MATERIALS AND METHODS

Twenty-one patients underwent MR imaging of the brain at 1.5T sequentially with both a 12-channel and a 32-channel receive-only phased-array head coil. Axial T2WIs, T1WIs, FLAIR images, and DWIs were acquired. Anonymized images were compared side-by-side and by sequence for image quality, lesion evaluation, and artifacts by 3 neuroradiologists. Results of the comparison were analyzed for the preference for a specific head coil.

RESULTS

FLAIR and DWI images acquired with the 32-channel coil showed significant improvement in image quality in several parameters. T2WIs also improved significantly with acquisition by the 32-channel coil, while T1WIs improved in a limited number of parameters. While lesion evaluation also improved with acquisition of images by the 32-channel coil, there was no apparent improvement in diagnostic quality. There was no difference in artifacts between the 2 coils.

CONCLUSIONS

Improvements in SNR and spatial resolution attributed to image acquisition with a 32-channel head coil are paralleled by perceived improvements in image quality.

MDCT angiography of the spinal vasculature and the artery of Adamkiewicz

OBJECTIVE

The purpose of our study was to prospectively assess 40-MDCT technology in combination with adapted brain reconstruction algorithms to visualize the spinal vasculature, in particular the artery of Adamkiewicz and its anatomic variants.

SUBJECTS AND METHODS

One hundred patients underwent contrast-enhanced MDCT of the thoracolumbar junction with collimation of 40 x 0.625 mm. The adapted brain algorithm reconstructed the spinal canal with a field of view of 90 mm at 0.6-mm slice thickness. Curved multiplanar reformations identified the artery of Adamkiewicz as a continuous vascular tract extending from the aortic orifices of the intercostal or lumbar arteries via the anterior radiculomedullary artery to the anterior spinal artery. Segment of origin and length were noted. Diameter and contrast-to-noise ratio (CNR) were evaluated along the posterior branch, the radiculomedullary artery, the artery of Adamkiewicz, and the anterior spinal artery. Univariate general linear model analysis with Bonferroni post hoc corrections evaluated whether laterality, segment of origin, and length of the artery of Adamkiewicz showed a sex-specific propensity. Multivariate general linear model analysis assessed whether spinal vascular diameters and intraluminal CNR showed correlations with sex, laterality, and segment of origin. Finally, the luminal diameters of the feeding posterior branches were statistically compared with those of the ipsilateral and contralateral adjacent posterior branches.

RESULTS

Successful depiction of the artery of Adamkiewicz was achieved in all patients; longitudinally the artery measured 40.1 +/- 13.51 mm. In 63% of patients it originated from the left side of the body, and in 74% it originated from the level of the 10th-12th thoracic vertebrae. Duplications were found in 5% of patients. Segmental distribution, laterality, and length did not show significant sex-specific differences (p > 0.05). The vascular diameter and luminal contrast did not show significant differences caused by sex, laterality, or segment of origin (p > 0.05). The diameter of the posterior branches (2.8 +/- 0.71 mm) arising in the segments of origin showed a significantly wider lumen than any of the other posterior branches (contralateral, 1.9 +/- 0.32 mm; upper ipsilateral, 2.0 +/- 0.47 mm; lower ipsilateral, 1.9 +/- 0.39 mm) (p < 0.0001).

CONCLUSION

Contrast-enhanced 40-MDCT technology, in combination with an adapted brain reconstruction algorithm, can depict the artery of Adamkiewicz and its anatomic variants.

Volumetric Assessment of Pulmonary Nodules with ECG-Gated MDCT

OBJECTIVE

The objective of our study was to assess physiologic lung deformation and compression originating from cardiovascular motion and their subsequent impact on determining the volume of small pulmonary nodules throughout the cardiac cycle on ECG-gated MDCT.

SUBJECTS AND METHODS

Seventy-three small noncalcified pulmonary nodules were identified in 30 patients who underwent ECG-gated MDCT. The volume of each nodule was assessed throughout the cardiac cycle using computer-aided automatic segmentation algorithms, and the assessment was repeated three times. To ensure the validity of the subtle changes in volume that were detected, we determined the volume and signal attenuation in phantom data sets and patient nodules without temporal or spatial differentiation. Subsequently, nodules were assigned to pulmonary segments, and volume changes were correlated to cardiac phases, nodular location, and mean nodular size. Statistical multivariate tests were performed to evaluate significant patterns.

RESULTS

The validity of significant measurements was proven in evaluated phantom data sets with a general tendency toward overestimating nodular volume (p = 0.492). Statistical evaluation of nodular signal attenuation confirmed true deformation and compression of nodules rather than partial volume effects as the reason for volume variations (p = 0.874). Differentiating pulmonary nodules in cardiac phases, pulmonary locations, and mean nodular volumes, we found that one single effect did not determine the amount of cardiovascular motion conveyed to pulmonary parenchyma and subsequently led to nodule deformation. Multivariate testing revealed statistically significant measures identifying patterns correlating variation in nodular volume with cardiac phase (p < 0.001), nodular location (p = 0.007), and mean nodular size (p < 0.001).

CONCLUSION

Cardiovascular motion was disproportionately conveyed to various pulmonary segments and led to changes in the volume of pulmonary nodules, especially in small pulmonary nodules. A precise volumetric assessment was therefore possible only by identifying the underlying cardiac phase.