蛛网膜下腔出血后症状性血管痉挛的检测:单次和连续动脉自旋标记的初步应用

目的采用动脉自旋标记(ASL)检测蛛网膜下腔出血术后的症状半球。方法研究包括18例动脉瘤所致蛛网膜下腔出血的病人,4例术后出现症状性血管痉挛。全部病人在第9～10天进行ASL检查(单次ASL)。9例病人分别在第1～2天、9～10天和13～21天进行连续ASL检查(连续ASL),7例病人在第4～7天也进行了检查。测量大脑中动脉供血区后部的脑血流量(CBF),估算同侧/对侧的CBF比例。通过受试者操作特征(ROC)曲线分析症状半球和其他部位之间的差异。结果单次ASL显示,CBF第9～10天和CBF同侧/对侧第9～10天在症状半球明显低于非症状半球(P<0.001)。连续ASL显示,CBF第4～7天较CBF第1～2天明显降低,CBF第9～10天较CBF第4～7天明显降低,而CBF第13～21天较CBF第9～10天明显升高。单次ASL的ROC分析显示CBF第9～10天的曲线下面积为0.95,明显高于CBF同侧/对侧第9～10天(P<0.001)。连续ASL的ROC分析显示CBF第9～10天的曲线下面积为0.93,明显高于CBF第9～10天/第1～2天和CBF同侧/对侧第9～10天(P<0.001)。结论单次ASL显示症状半球较非症状半球CBF明显减低。连续ASL可显示蛛网膜下腔出血后CBF随时间的变化。     

Intra-arterial nimodipine for the treatment of symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage: preliminary results

BACKGROUND AND PURPOSE: Cerebral vasospasm remains a major problem in patients recovering from aneurysmal subarachnoid hemorrhage despite advances in medical, surgical, and endovascular care. Our purpose was to assess the efficacy of intra-arterial nimodipine, a calcium-channel blocker acting mainly on cerebral vessels, in preventing delayed neurologic deficits in patients with symptomatic vasospasm. METHODS: Clinical charts of 25 consecutively treated patients were retrospectively reviewed. A multifactorial decision tree was used to determine the indication for angiography and subsequent endovascular treatment. Nimodipine was infused intra-arterially via a diagnostic catheter in the internal carotid artery or vertebral artery at a rate of 0.1 mg/min. Angiographic vasospasm before endovascular treatment, immediate vessel caliber modifications, and short- and long-term clinical efficacy of the procedure were assessed. RESULTS: Thirty procedures were performed in 25 patients. Clinical improvement was observed in 19 (76%), 16 of whom improved after the first endovascular procedure, two after the second intra-arterial treatment, and one after the third. Of these 19 patients, only 12 (63%) had notable vascular dilatation at postprocedural angiography. Dilatation of infused vessels occurred in only 13 (43%) of 30 procedures. After follow-up of 3-6 months, 18 (72%) of 25 patients had a favorable outcome (Glasgow outcome scale score of 1-2 and modified Rankin scale score of 0-2). No complications were observed. CONCLUSION: Intra-arterial nimodipine is effective and safe for the treatment of symptomatic vasospasm after subarachnoid hemorrhage. Further prospective randomized studies of cerebral blood flow are needed to confirm these results.     

Symptomatic vasospasm after subarachnoid haemorrhage: assessment of brain damage by diffusion and perfusion-weighted MRI and single-photon emission computed tomography

Our purpose was to assess the usefulness of diffusion- and perfusion-weighted MRI for the detection of ischaemic brain damage in patients with suspected vasospasm after subarachnoid haemorrhage (SAH). We studied 11 patients admitted with a ruptured aneurysm of the anterior circulation and suspected of intracranial vasospasm on clinical examination and transcranial Doppler sonography (TCD). All were investigated by technetium-hexamethyl-propylene amine oxime (Tc-HMPAO) single photon emission computed tomography (SPECT) and diffusion and perfusion-weighted MRI (DWI, PWI) within 2 weeks of their SAH. Trace images and TTP maps were interpreted by two examiners and compared with clinical and imaging follow-up. PWI revealed an area of slowed flow in seven patients, including four with major and three with minor hypoperfusion on SPECT. In two patients, PWI did not demonstrate any abnormality, while SPECT revealed major hypoperfusion in one and a minor deficit hypoperfusion in the other. Two patients with high signal on DWI had a permanent neurological deficit.     

Cortical blood flow during cerebral vasospasm after aneurysmal subarachnoid hemorrhage: three-dimensional N-isopropyl-p-[(123)I]iodoamphetamine single photon emission CT findings

BACKGROUND AND PURPOSE: The relationship between regional cerebral blood flow (rCBF) during cerebral vasospasm after subarachnoid hemorrhage (SAH) and angiographic vasospasm and the value of rCBF in predicting vasospasm and the prognosis are not fully delineated. Our aim was to investigate the changes in extent of vasospasm-induced decreased cortical rCBF on three-dimensional (3D) displays of single photon emission CT (SPECT) findings. The clinical usefulness of these assessments was analyzed. METHODS: In 58 cases of SAH, SPECT and digital subtraction angiography were performed on the same day, 5-9 days after SAH or within 24 hours after the onset of delayed ischemic neurologic deficit (DIND). Cerebral blood flow data were assessed by measuring the area of decreased cortical rCBF on 3D SPECT images. RESULTS: The area of decreased cortical rCBF on the 3D images was significantly increased in cases with DIND (P <.001), in cases with a large infarction due to vasospasm (P =.006), and in cases with a poor prognosis after vasospasm (P =.045). These increases were also related to the type of angiographic vasospasm; the greatest decrease in cortical rCBF occurred in the combined type (combination of the peripheral and proximal types) of vasospasm, followed by cases with the peripheral type, proximal type, and no angiographic vasospasm. In cases with DIND, patchy decreased cortical rCBF areas were seen before the onset of DIND. CONCLUSION: Combined-type vasospasm leads to reductions in CBF greater than those due to isolated peripheral or proximal vasospasm. Two-dimensional and mean-hemispheric CBF analyses are less sensitive for this change than is 3D SPECT.     

Safety and feasibility of intra-arterial nicardipine for the treatment of subarachnoid hemorrhage-associated vasospasm: initial clinical experience with high-dose infusions

BACKGROUND AND PURPOSE: Delayed cerebral ischemia from vasospasm is a major complication after aneurysmal subarachnoid hemorrhage (SAH), but complications and/or low efficacy are associated with current therapy. We report our initial experience with intra-arterial use of a calcium channel blocker, nicardipine. MATERIALS AND METHODS: A retrospective review of a consecutive series of patients with clinical and angiographic vasospasm treated with intra-arterial nicardipine was performed. Standard criteria for definition of significant, intractable vasospasm after aneurysmal SAH were used. After catheter angiographic confirmation of vasospasm, arteries showing severe narrowing were targeted for superselective catheterization. Nicardipine was infused at a high dose rate (0.415-0.81 mg/min). Contrast injections were performed at 2-5-mg intervals to assess effective response (a 60% increase in arterial diameter of the most severely decreased in caliber vessel compared with the very first angiographic run). RESULTS: Eleven consecutive patients underwent a total of 20 procedures; most had SAH with high Hunt and Hess grades (III or IV). All had depressed level of consciousness; others had paresis (7/20, 35%), aphasia (1/20, 5%), and facial nerve palsy (1/20, 5%). Between 10 and 40 mg of nicardipine was used. A 60% increase in diameter of the main affected artery compared with the initial diameter measured in the initial angiographic run was achieved in all procedures. Clinical improvement (resolved focal symptoms or increased Glasgow Coma Score) occurred in 10 of 11 patients (91%). One patient died from complications of the initial hemorrhage. No complications occurred after 16 of 20 procedures (80%); minor complications without sequelae occurred after the remaining procedures. Follow-up of at least 2 months in 10 survivors revealed minor or no deficits in most patients with a Glasgow Outcome Score of 1 or 2 in 9 of 10 patients (90%). CONCLUSION: In this small series, high-dose intra-arterial nicardipine infusion to treat SAH-associated vasospasm seems to be safe and effective.     

Brain SPECT used to evaluate vasospasm after subarachnoid hemorrhage: correlation with angiography and transcranial Doppler

PURPOSE: The primary objective of this study was to correlate Tc-99m HMPAO and ethyl cysteine dimer perfusion brain SPECT imaging with angiography and transcranial Doppler (TCD) to identify vasospasm after subarachnoid hemorrhage. METHODS: A retrospective analysis of consecutive patients who had cerebral blood flow SPECT imaging for subarachnoid hemorrhage and aneurysm clipping was made. Flow velocity measurements were correlated using TCD and cerebrovascular angiography. RESULTS: Of the 129 patients were included in this study, 84 were female and 45 were male, with a mean age of 51.9 years and a median age of 51 years (range, 9 to 84 years). Eighty-nine patients had brain SPECT evidence of hypoperfusion. Concordance was found between SPECT and TCD with vasospasm in 57 of 89 (64%) patients and nonconcordance was evident in 32 patients (36%). Eleven patients who had concordance between SPECT and TCD had nonconcordant results of angiography for vasospasm. CONCLUSIONS: These findings suggest that all three methods are complementary to each other in the evaluation of patients with vasospasm after subarachnoid hemorrhage. Concordance of 64% between SPECT and TCD is acceptable and explicable by the differences in technique and measurement of cerebral blood flow compared with vascular narrowing, respectively.     

Detection of postoperative residual cholesteatoma with delayed contrast-enhanced MR imaging: initial findings

Our objective was to assess the value of delayed contrast-enhanced T1-weighted spin-echo MR imaging in the detection of residual cholesteatoma in patients who have undergone canal wall-up tympanoplasty procedure. The MR imaging was obtained prior to revision surgery in 18 patients with opacity of the post-operative cavity at CT examination 12–18 months after canal wall-up tympanoplasty. In each patient the following was performed: precontrast T1- and T2-weighted images; and early and delayed contrast-enhanced axial and coronal T1-weighted imaging. Early and delayed MR imaging results were separately compared with surgical second-look findings. Sensitivity, specificity, and predictive values were evaluated for early and delayed post-contrast MR imaging, compared with second-look surgery findings. A residual cholesteatoma was correctly identified in 8 of 9 cases with delayed contrast-enhanced T1-weighted MR imaging. Mean sensitivity, specificity, positive predictive value, and interobserver agreement (evaluated by kappa statistics) were, respectively, 85.2, 92.6, 92.6%, and kappa=0.78 for the delayed contrast-enhanced MR imaging technique. The same parameters were, respectively, 96.3, 33.3, 60.6, and 0.30 for the early contrast-enhanced T1-weighted MR images. We conclude that delayed contrast-enhanced T1-weighted MR imaging is reliable for the detection of residual cholesteatomas of the middle ear in patients who have undergone canal wall-up tympanoplasty. Electronic Publication     

CBF measurements using multidelay pseudocontinuous and velocity-selective arterial spin labeling in patients with long arterial transit delays: comparison with xenon CT CBF

Purpose:

To test the theory that velocity‐selective arterial spin labeling (VSASL) is insensitive to transit delay.

Materials and Methods:

Cerebral blood flow (CBF) was measured in ten Moyamoya disease patients using xenon computed tomography (xeCT) and magnetic resonance imaging (MRI), which included multiple pseudo‐continuous ASL (pcASL) with different postlabel delays, VSASL, and dynamic susceptibility contrast (DSC) imaging. Correlation coefficient, root‐mean‐square difference, mean CBF error between ASL, and gold‐standard xeCT CBF measurements as well the dependence of this error on transit delay (TD) as estimated by DSC time‐to‐peak of the residue function (Tmax) were determined.

Results:

For pcASL with different postlabel delay time (PLD), CBF measurement with short PLD (1.5–2 sec) had the strongest correlations with xeCT; VSASL had a lower but still significant correlation with a mean coefficient of 0.55. We noted the theoretically predicted dependence of CBF error on Tmax and on PLD for pcASL; VSASL CBF measurements had the least dependence of the error on TD. We also noted effects suggesting that the location of the label decay (blood vs. tissue) impacted the measurement, which was worse for pcASL than for VSASL.

Conclusion:

We conclude that VSASL is less sensitive to TD than conventional ASL techniques and holds promise for CBF measurements in cerebrovascular diseases with slow flow. J. Magn. Reson. Imaging 2012;36:110–119. © 2012 Wiley Periodicals, Inc.     

Perfusion MRI of brain tumours: a comparative study of pseudo-continuous arterial spin labelling and dynamic susceptibility contrast imaging

Introduction  

The purpose of this study was to compare the non-invasive 3D pseudo-continuous arterial spin labelling (PC ASL) technique with the clinically established dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-MRI) for evaluation of brain tumours.     

Intracranial angioplasty for treatment of vasospasm after subarachnoid hemorrhage: technique and modifications to improve branch access

Angioplasty of the proximal portions of major cerebral arteries at the base of the brain has shown promise as a therapy for symptomatic vasospasm after subarachnoid hemorrhage. The blind-ended, single-lumen balloon-dilatation catheter most widely used to date lacks steerability, limiting its application to unbranched stems and single branches at bi- or trifurcation points. To extend the capabilities of cerebral angioplasty, we describe two modifications of the basic technique that have allowed increased selectivity and successful angioplasty of multiple branches, both proximal and distal, involved by vasospasm. Of four patients treated, three showed early improvement in their clinical condition, likely attributable to the angioplasty procedure. Our modifications to the basic angioplasty technique enhanced its success. Further refinement of this technique in the treatment of vasospasm will make it safer in treating this serious and widespread disorder.     

Accurate myocardial T1 measurements: toward quantification of myocardial blood flow with arterial spin labeling.

In this study, we investigated a method for accurately measuring myocardial T(1) for the quantification of myocardial blood flow (MBF) with arterial spin labeling (ASL). A single-shot gradient-echo (GE)-based ASL sequence with an adiabatic hyperbolic secant inversion recovery pulse was modified to acquire a pair of myocardial T(1)'s within a breath-hold. A multivariable regression algorithm that accounted for the magnetization saturation effects was developed to calculate T(1). The MBF was then determined with a well-developed model. The accuracy of our T(1) calculation was first evaluated in a phantom, and then in six dogs for the MBF calculation, with (N = 4) and without (N = 2) coronary artery stenosis. In the phantom study, the accuracy of T(1) measured with a slice-selective inversion prepared pulse was within 2.5% of error. In healthy dogs, the MBF increased 2-5 times during vasodilation. In contrast, regional differences of MBF were well visualized in the stenotic dogs during vasodilation (perfusion reserve of 2.75 +/- 0.83 in normal myocardium, and 1.46 +/- 0.75 in the stenotic area). A correlation analysis revealed a close agreement in MBF between the ASL and microsphere (MS) in both healthy and stenotic dogs. In summary, the modified ASL technique and T(1) regression algorithm proposed here provide an accurate measurement of myocardial T(1) and demonstrate potential for reliably assessing MBF at steady state.     

Prediction of delayed neurological deficit after subarachnoid haemorrhage: a CT blood load and Doppler velocity approach

The predictive value of cranial computed tomography (CT) blood load and serial transcranial Doppler sonography for the development of delayed ischaemic neurological deficit was assessed in 121 patients following subarachnoid haemorrhage. Of the 121 patients, 81 (67%) had thick layers of blood or haematoma, including intraventricular bleeding. The proportion of patients who developed delayed deficit was higher with increasing amounts of subarachnoid blood on the admission CT (51% of 53 cases in Fisher grade 3; 35% of 33 cases in grade 2; 28% of 7 cases in grade 1,P<0.01). Doppler velocities obtained from readings at least every 2 days following admission were higher in patients with delayed neurological deficit (peak velocity for grade 3 patients 176±6 cm/s (mean±SE), versus grade 2: 164±7 cm/s; grade 4 149±9, bothP=0.04, Mann-Whitney). Peak velocity and maximal 24-h rise tended to be higher within different CT grades in patients with a deficit than in those without; this difference was significant for grade 3 patients (P<0.01). We conclude that a combined approach with CT and Doppler sonography provides greater predictive value for the development of delayed ischaemic neurological deficit than either test considered independently. The value of Doppler sonography may be greatest for patients with Fisher grade 3 blood, in whom the risk of delayed ischaemia is greatest.     

Multidetector-row CT angiography of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: comparison of volume-rendered images and digital subtraction angiography

BACKGROUND AND PURPOSE: Cerebral vasospasm remains a major problem in patients recovering after surgical treatment of cerebral aneurysms. The purpose of this study was to evaluate cerebral vasospasm at multidetector-row spiral CT angiography (MDCTA) compared with digital subtraction angiography (DSA) in patients with aneurysmal subarachnoid hemorrhages (SAHs). METHODS: Seventeen patients suspected of having vasospasm on clinical findings underwent both postoperative MDCTA and DSA. MDCTA was analyzed by using volume-rendered images as well as axial images. A total of 251 arterial segments were analyzed for vasospasm by using a 5-point grading system. The MDCTA results were then compared with findings on the corresponding DSA images. Sensitivity, specificity, and accuracy of MDCTA for detection of hemodynamically significant spasms were also calculated, with findings at DSA used as the reference standard. RESULTS: On DSA, 74 spasmatic segments were found among the 251 segments evaluated, and 40 segments with hemodynamically significant vasospasms were present. The overall agreement between MDCTA and DSA was 95.2%. We had 12 (4.8%) cases of disagreement between MDCTA and DSA. In 11 segments, the degree of stenosis was overestimated at MDCTA. Overall accuracy, sensitivity and specificity of MDCTA in the detection of hemodynamically significant vasospasm were 97.5%, 98.1%, and 98.0%, respectively, with positive and negative predictive values of 90.7% and 99.5%. CONCLUSION: MDCTA appears to be a reliable alternative imaging technique to DSA in the assessment of patients with cerebral vasospasm after aneurysmal SAH.     

Bile duct injuries leading to portal vein obliteration after transcatheter arterial chemoembolization in the liver: CT findings and initial observations.

PURPOSE: To document the computed tomographic (CT) findings of transcatheter arterial chemoembolization (TACE)-induced, localized bile duct injuries leading to portal vein branch obliteration in the liver and to elucidate the clinical implications with retrospective review of the authors' experiences. MATERIALS AND METHODS: Follow-up CT scans obtained in 11 patients with TACE-induced intrahepatic bile duct dilatation were reviewed retrospectively to evaluate serial changes in the adjacent portal vein branches and hepatic parenchyma. Clinical data, including time between TACE and CT and serum alkaline phosphatase levels, also were analyzed. RESULTS: Of 11 patients with marked (n = 8) or mild (n = 3), lobar (n = 4) or segmental (n = 7) bile duct dilatation with or without bile collection in the tissue sheaths of the Glisson capsule or hepatic parenchyma, nine (82%) had bile duct changes at the first CT follow-up, within 1 month after TACE. Marked narrowing or obliteration of the adjacent intrahepatic portal vein branches in 10 (91%) patients resulted in progressive atrophy of the corresponding hepatic parenchyma in nine (82%) at variable times after TACE. The serum alkaline phosphatase level increased to more than 200 U/L in eight (89%) of nine patients 1 month after TACE. CONCLUSION: TACE-induced intrahepatic bile duct injury resulting in obliteration of the adjacent portal vein branch seems to be one cause of hepatic parenchymal atrophic changes after TACE.     

CT angiography and perfusion imaging in patients with subarachnoid hemorrhage: correlation of vasospasm to perfusion abnormality

INTRODUCTION: We retrospectively evaluated computed tomography angiography (CTA) and perfusion imaging (CTP) of patients with aneurysmal subarachnoid hemorrhage (SAH) for any correlation between degree of vasospasm and perfusion deficit. MATERIALS AND METHODS: Sequentially performed CTP and CTA of 41 patients at least at the third day of postbleeding were reviewed for vasospasm and perfusion deficit throughout the anterior and middle cerebral arteries and corresponding territories. Vasospasm was noted comparing the contralateral normal ones or extradural components of the vessel itself and graded to negative, mild, moderate, and severe as luminal narrowing none, <25%, between 25% and 50%, and >/=50%, respectively. CTP abnormality was noted using cerebral blood flow and volume and mean transit time maps. RESULTS: Of 41 patients, 20 had no vasospasm; 15 had mild to moderate and six had severe vasospasm. Three of 20 patients with no vasospasm (15%), four of 15 patients with mild to moderate vasospasm (26%), and five of six patients with severe vasospasm (83%) had perfusion abnormality. Perfusion abnormalities noted were ischemia, infarction, and hyperperfusion. Perfusion abnormality without vasospasm was observed in the watershed areas and adjacent to sulcal clots. CONCLUSION: In SAH patients, if there is a macrovascular vasospasm with luminal narrowing >/=50%, there is a high likelihood (83%) of perfusion abnormality in the territory of the vasospastic vessel. There may also be perfusion abnormality without macrovascular vasospasm in the watershed areas or in the vicinity of sulcal clots.     

Primary tumors and mediastinal lymph nodes after neoadjuvant concurrent chemoradiotherapy of lung cancer: serial CT findings with pathologic correlation

PURPOSE: The purpose of this work was to describe the changes of primary tumor and mediastinal lymph nodes on CT after neoadjuvant concurrent chemoradiotherapy and to correlate the CT findings with pathology. METHOD: Twenty-one consecutive patients [N2 disease (n = 19) or resectable T4 and N2 disease (n = 2)] with non-small cell lung cancer underwent neoadjuvant concurrent chemoradiotherapy. Changes of primary tumor and mediastinal nodes before and after the therapy were assessed using CT. The CT findings were correlated with pathologic findings. RESULTS: With neoadjuvant therapy, decrease in T stage was achieved in 9 of 21 (43%) patients on CT. On pathology, the remaining tumor consisted mostly of fibrosis and necrosis with little proportion of viable tumor cells (mean volume 17%, range 0-55%). Decrease in nodal stage was achieved in 14 of 21 (67%) patients on pathologic examination. Seven patients had cancer cells in mediastinal lymph nodes: in 6 of 9 (67%) patients with adenocarcinoma and 1 of 12 (8%) patients with squamous cell carcinoma (p = 0.016). CONCLUSION: With neoadjuvant concurrent chemoradiotherapy, the remaining tumor consists mostly of fibrosis or necrosis. Decreased nodal stage on pathology is achieved especially in patients with N2 disease of squamous cell carcinoma. The CT findings of the tumor and mediastinal nodes are not helpful in predicting the pathology after the therapy.     

Quantification of area and percentage of infarcted myocardium by single photon emission computed tomography with thallium-201 : A comparison with serial serum CK-MB measurements

In order to quantify the size of the infarcted myocardium, two kinds of data processing techniques were applied to single photon emission computed tomography (SPECT) with thallium-201 and its clinical reliability was evaluated by comparing it with the infarct sizing procedure with the serial serum creatine kinase-MB measurements in 14 patients with acute myocardial infarction. After maximum-count circumferential profile analysis, short axis images were reformatted into an unfolded surface map and a bull's eye view map. The SPECT-determined infarct size was defined as the area or the percentage of hypoperfused myocardium of which the profile count was less than the mean minus 2SD derived from 8 normal subjects. The infarct area was calculated from the number of pixels with an abnormal count and expressed in an unfolded surface map. The percentage was calculated from the number of abnormal profile points and displayed in a bull's eye view map. A high linear correlation was observed between the enzymatically determined infarct size and the infarct area or the percentage (r = .947, r = .872, respectively), despite underestimations in 2 patients with accompanying right ventricular infarction and overestimations in 2 patients with prior anterior infarction. Moreover, a close negative correlation was found between the left ventricular ejection fraction and the infarct area or the percentage (r = .836, r = .821, respectively). Thus, the semiautomatic techniques for processing thallium-201 SPECT images might contribute to the quantitative estimation and display of infarcted myocardium and have high clinical reliability.