Usefulness of Ictal and Interictal 99mTC Ethyl Cysteinate Dimer Single Photon Emission Computed Tomography in Patients with Refractory Partial Epilepsy

Summary: Purpose: Ictal perfusion single photon emission computed tomography (SPECT), using HMPAO, has been shown to localize epileptic foci in ～90% of studies. Unfortunately, HMPAO decomposes rapidly, precluding the performance of ictal studies. Ethyl cysteinate dimer (ECD) is a SPECT perfusion agent recently approved by the Food and Drug Administration. After preparation, this compound is stable for ～6 h. facilitating the performance of ictal studies. Methods: In a prospective, open-label, uncontrolled, non randomized study, we evaluated the potential benefits of the use of ^99mTc-ECD SPECT for lateralization of the epileptic focus. Ten consecutive adult epilepsy surgery candidates were studied with ictal and interictal ^99mTc-ECD SPECT. Results: The mean delay between seizure onset and ictal SPECT injection was 23.2 s. The mean seizure duration was 84.1 s. Ictal studies agreement between the epilepsy focus and area of hyperperfusion was evident in 8 of 10 cases. In one case, SPECT was lateralized in a patient with bilateral temporal lobe epilepsy (TLE); however, hyperperfusion was observed on the same side of that particular seizure. In another case, there was location disagreement. Interictal SPECT showed focal hypoperfusion in three cases. Conclusions: ^99mTc-ECD proved to be an optimal tracer for ictal studies. Although this is a small series, the results of ictal and interictal findings using 99mTc-ECD are similar to those reported with ^99mTc-HMPA0. Because ^99mTc-ECD has a longer decomposition time, true ictal studies are easier to obtain. This new tracer will probably allow the use of ictal SPECT to become widely accepted in most epilepsy centers.     

99mTc-ethyl cysteinate dimer brain SPECT findings in early stage of dementia with Lewy bodies and Parkinson's disease patients: a correlation with neuropsychological tests

We examined clinical presentations, neuropsychological findings, and perfusion patterns of ^99mTc-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients with early stage dementia with Lewy bodies (DLB) ( n  = 17) and Parkinson's disease (PD) ( n  = 16), with age-matched healthy controls ( n  = 10). Seven paired regions of interest (ROIs) were drawn manually including inferior frontal, temporal, parietal, occipital, parieto-occipital junction, striatum and thalamus for semiquantitative measurement. Neuropsychological tests were applied for clinical correlation. The SPECT results showed significant hypoperfusion in DLB group in frontal, parietal, thalamus, temporal ROIs compared with controls ( P  < 0.01) whilst signals in temporal areas was significantly reduced compared with PD group ( P  < 0.05). Neuropsychological tests showed that DLB patients had deficits in mental manipulation, short-term memory, abstract thinking, drawing and semantic verbal fluencies ( P  < 0.05, compared with control). In addition, DLB group had lower scores than those with PD in mental manipulation, drawing and semantic verbal fluency ( P  < 0.05). Our study showed that even in early stages of DLB, neuropsychological and perfusion patterns were evident and may be different from PD group, despite they shared certain similarities both in neuropsychological and image findings compared with age-matched controls.     

Dissociation of 99mTc-ECD and 99mTc-HMPAO distributions in herpes simplex encephalitis

In herpes simplex encephalitis (HSE), the authors noted an evident dissociation between the ^99mTc-ethyl cysteinate dimer (ECD) and ^99mTc-d,l-hexamethyl-propylene- amine oxime (HMPAO) single photon emission computed tomographies (SPECTs). The patient was a 5-year-old boy with diffuse type of pontine glioma, which was treated with hyperfractionated radiotherapy. Two weeks after the completion of radiation therapy, a lesion suggesting that of HSE was noted in the right frontotemporal region on magnetic resonance images. ^99mTc-HMPAO SPECT showed an increased accumulation of the tracer in this lesion. On the ^99mTc-ECD dynamic SPECT, an exaggerated accumulation of the tracer was noted within 80 s of administration, followed by a rapid drop in the accumulation, resulting in a low accumulation in 10 min. It was assumed that this dissociation was due to the different mechanisms to trap HMPAO and ECD in the brain tissue. Received: 30 September 1995 Revised: 29 February 1996     

New open‐source ictal SPECT analysis method implemented in BioImage Suite

Ictal single photon emission computed tomography (SPECT) is a powerful tool for noninvasive seizure localization, but it has been underutilized because of practical challenges, including difficulty in implementing ictal‐interictal SPECT difference analysis. We previously validated a freely available utility for this purpose, ictal‐interictal subtraction analysis by statistical parametric mapping (SPM) (ISAS). To further simplify and improve the difference imaging technique, we now compare a new algorithm, ISAS BioImage Suite (see http://spect.yale.edu and http://bioimagesuite.org ), to the original ISAS method in 13 patients with known seizure localization. We found that ISAS BioImage Suite was in agreement with the original algorithm in all cases for which ISAS correctly identified a single unambiguous region of seizure onset. We also tested for possible effects of scan‐order bias in the control group used for the analysis and found no significant effect on the results. These findings establish a simple, validated and objective method for analyzing ictal‐interictal SPECT difference images for use in the care of patients with epilepsy.     

Interictal PET and ictal subtraction SPECT: Sensitivity in the detection of seizure foci in patients with medically intractable epilepsy

Purpose: Interictal positron emission tomography (PET) and ictal subtraction single photon emission computed tomography (SPECT) of the brain have been shown to be valuable tests in the presurgical evaluation of epilepsy. To determine the relative utility of these methods in the localization of seizure foci, we compared interictal PET and ictal subtraction SPECT to subdural and depth electrode recordings in patients with medically intractable epilepsy. Methods: Between 2003 and 2009, clinical information on all patients at our institution undergoing intracranial electroencephalography (EEG) monitoring was charted in a prospectively recorded database. Patients who underwent preoperative interictal PET and ictal subtraction SPECT were selected from this database. Patient characteristics and the findings on preoperative interictal PET and ictal subtraction SPECT were analyzed. Sensitivity of detection of seizure foci for each modality, as compared to intracranial EEG monitoring, was calculated. Key Findings: Fifty‐three patients underwent intracranial EEG monitoring with preoperative interictal PET and ictal subtraction SPECT scans. The average patient age was 32.7 years (median 32 years, range 1–60 years). Twenty‐seven patients had findings of reduced metabolism on interictal PET scan, whereas all 53 patients studied demonstrated a region of relative hyperperfusion on ictal subtraction SPECT suggestive of an epileptogenic zone. Intracranial EEG monitoring identified a single seizure focus in 45 patients, with 39 eventually undergoing resective surgery. Of the 45 patients in whom a seizure focus was localized, PET scan identified the same region in 25 cases (56% sensitivity) and SPECT in 39 cases (87% sensitivity). Intracranial EEG was concordant with at least one study in 41 cases (91%) and both studies in 23 cases (51%). In 16 (80%) of 20 cases where PET did not correlate with intracranial EEG, the SPECT study was concordant. Conversely, PET and intracranial EEG were concordant in two (33%) of the six cases where the SPECT did not demonstrate the seizure focus outlined by intracranial EEG. Thirty‐three patients had surgical resection and >2 years of follow‐up, and 21 of these (64%) had Engel class 1 outcome. No significant effect of imaging concordance on seizure outcome was seen. Significance: Interictal PET and ictal subtraction SPECT studies can provide important information in the preoperative evaluation of medically intractable epilepsy. Of the two studies, ictal subtraction SPECT appears to be the more sensitive. When both studies are used together, however, they can provide complementary information.     

多巴胺转运体SPECT显像评估帕金森病严重程度的研究

目的本研究探讨显像评估帕金森病严重程度的意义.方法对15例对照者和30例帕金森病患者(根据Hoehn-Yahr分级分为早期组18例,中晚期组12例)行99mTc-TRODAT-1 DAT SPECT断层显像,注射示踪剂2～3 h后采集图像,勾画出感兴趣区(双侧纹状体和枕叶),计算机自动计算感兴趣区的放射性计数,最后测算出纹状体与枕叶部位的放射性计数比值和非对称性指数,并进行比较分析.结果对照组特异性放射性计数比值是0.58±0.16(左侧)、0.56±0.32(右侧),早期帕金森病组特异性放射性计数比值为0.40±0.33(症状对侧或症状严重肢体对侧)、0.51±0.12(症状同侧),中晚期帕金森病组特异性放射性计数比值为0.23±0.18(症状严重肢体对侧)、0.40±0.17(症状同侧);对照组非对称性指数是5.12±0.48,早期帕金森病组为9.05±14.61,中晚期组为20.67±14.2,3组间比较均有显著性差异(P＜0.05).结论多巴胺转运体99mTc-TRODAT-1 SPECT显像有助于帕金森病严重程度的判断.     

Magnetoencephalography and ictal SPECT in patients with failed epilepsy surgery

Objective

Selected patients with intractable focal epilepsy who have failed a previous epilepsy surgery can become seizure-free with reoperation. Preoperative evaluation is exceedingly challenging in this cohort. We aim to investigate the diagnostic value of two noninvasive approaches, magnetoencephalography (MEG) and ictal single-photon emission computed tomography (SPECT), in patients with failed epilepsy surgery.

TIA患者脑SPECT血流灌注显像的研究

目的探讨短暂性脑缺血发作(TIA)间歇期的局部脑血流状况.方法用99mTc-ECD对41例TIA患者进行脑SPECT血流灌注显像,分析轻、中及重度低灌注与TIA时的临床神经功能缺损评分及TIA次数的关系,并与同期脑CT结果进行对比分析.结果所有患者的脑SPECT灌注显像均有不同程度的低灌注区域,其中82.9%的患者发现有与症状相关的低灌注区,而脑CT仅显示了31.7%的临床责任病灶,SPECT的敏感性明显高于脑CT(x2=21.983,P＜0.01),且这种差异对脑叶尤其颞叶病灶表现得更明显(x2=31.694,P＜0.01);随着临床神经功能缺损程度的加重及TIA次数的增加,脑SPECT灌注显像低灌注区范围越大.结论SPECT发现的局部低灌注现象可能是以前或正在发生的临床或亚临床脑缺血事件的反映;用SPECT可观察TIA间歇期的脑血流状况,判断TIA的预后并调整治疗.     

SPECT findings during postictal psychoses: predominance of relative increase of perfusion in right temporal lobe

To identify brain regions activated during episodes of postictal psychoses (PIP), we investigated single-photon emission computed tomography (SPECT) data obtained from five patients treated at our institutions and also reviewed four previous studies. Therefore, SPECT findings in a total of 19 cases were analyzed, including 16 patients with temporal lobe epilepsy (TLE). During nonpsychotic states, the laterality of epileptic foci was judged as left-sided in nine episodes, right-sided in six episodes, and nonlateralized in four episodes. In PIP states, 88% of the patients showed a relative increase of right temporal perfusion (increased right temporal or decreased left temporal perfusion). Regardless of whether right- or left-sided pathology was suspected during a nonpsychotic state, SPECT findings obtained during PIP episodes revealed a trend of right-sided temporal predominance.     

Superiority of HMPAO ictal SPECT to ECD ictal SPECT in localizing the epileptogenic zone

PURPOSE: We examined diagnostic performances of Tc-99m hexamethylpropylene amine oxime (HMPAO) and Tc-99m electron capture detection (ECD) ictal single-photon emission computed tomography (SPECT) to localize the epileptogenic zones in mesial temporal lobe epilepsy (TLE) and neocortical epilepsy (NE). METHODS: Epileptogenic zones were identified by invasive EEG or surgical outcome. Ictal SPECT was performed with stabilized Tc-99m HMPAO (TLE, 17; NE, 23) and with Tc-99m ECD (TLE, 7; NE, 7). Single-blind visual interpretation was used to localize the epileptogenic zones. Asymmetric index was calculated. Subtraction ictal SPECT was coregistered to a magnetic resonance imaging (MRI) template. RESULTS: In TLE, the sensitivity of Tc-99m HMPAO SPECT was 82% (14 of 17) and that of Tc-99m ECD SPECT was 71% (five of seven). The asymmetric index (AI; 25 +/- 10) of Tc-99m HMPAO SPECT was larger (p = 0.05) than the AI (13 +/- 13) of Tc-99m ECD SPECT in patients with TLE. In NE, the sensitivity of Tc-99m HMPAO SPECT was 70% (16 of 23), but that of Tc-99m ECD SPECT was 29% (two of seven). The AI (15 +/- 10) of Tc-99m HMPAO SPECT was significantly larger (p = 0.02) than the AI (4.8 +/- 6) of Tc-99m ECD SPECT in patients with NE. Subtraction ictal SPECT coregistered to MRI supported the visual assessment. CONCLUSIONS: We concluded that the sensitivity of Tc-99m ECD ictal SPECT is similar to that of Tc-99m HMPAO ictal SPECT in TLE; however, ictal hyperperfusion was higher with the Tc-99m HMPAO SPECT. In patients with NE, Tc-99m HMPAO ictal SPECT also was superior to Tc-99m ECD ictal SPECT in sensitivity and degree of hyperperfusion.     

癫痫手术前SPECT的定位价值

目的：了解单光子发射计算机断层扫描（ＳＰＥＣＴ）行局部脑血流检查在致痫灶定位中的应用价值。方法：对２４例癫痫患者行ＳＰＥＣＴ检查，结果采用目测和半定量分析两种方法进行判断。结果：１３／２４（５６％）的患者有目测的异常灌注区，其中１１／１３（８５％）与综合定位的结果相一致，半定量分析的方法可发现１２／１２的患者有异常灌注区，其中１０／１２（８３％）可得到与综合定位结果相一致的结论。统计学显示两种方法在阳性检出率和准确率上有显著差异。结论：ＳＰＥＣＴ在致痫灶的定位中有较高的应用价值，半定量分析的方法可明显提高ＳＰＥＣＴ对致痫灶的检出率，但应将检查结果与临床及其他检查资料相结合进行分析以减少假阳性率     

脑磁图对难治性癫痫致痫区定位价值

目的探讨脑磁图癫痫定位技术对难治性癫痫致痫区定位的价值。方法回顾性分析难治性癫痫病人58例,术前行视频头皮脑电图、磁共振、脑磁图、颅内埋藏电极皮层脑电图等检查,综合评估确定致痫灶的位置。根据综合评估致痫区制定手术方案并实施,随访并判定疗效。根据脑磁图癫痫定位和综合评估致痫区吻合度分为3组,Ⅰa组：完全吻合一两区域中心位置在1cm以内,Ⅰb组：基本吻合一两区域中心位置在1～3cm;Ⅱ组：不吻合一两区域中心位置在3cm以外或其他。统计分析各组间疗效的差异。结果本组总有效率为77．6％（45／58）,其中癫痫完全消失18例;Ⅰa、Ⅰb组手术疗效无明显差异,但Ⅰ组手术疗效明显优于Ⅱ组。结论脑磁图癫痫定位是难治性癫痫术前评估的重要方法之一,当脑磁图癫痫定位和术前综合评估致痫区基本一致时,手术疗效相对较好。     

癫痫发作间期和亚临床发作期脑SPECT痫灶定位对比研究

目的：研究癫痫亚临床发作期和发作间期脑ＳＰＥＣＴ的痫灶定位诊断价值。方法：建立亚临床发作期脑血流灌注显像方法，与间期显像对比分析定位；并结合脑ＣＴ、ＥＥＧ、ＥＣｏＧ和疗效综合评价其痫灶定位诊断价值。结果：间期ＳＰＥＣＴ阳性率、准确率、灵敏度分别为：９０．９１％、７７．２７％、８９．４７％，亚临床发作期分别为：９５．４５％、９０．９１％、１００％，优于传统定位诊断。亚临床发作期病灶放射性摄取比值也有明显增加，ＥＣｏＧ、病检阳性率１００％，远期随访有效率９０．９１％。结论：ＳＰＣＥＴ具有较高的痫灶定位诊断价值，运用亚临床发作期显像可明显提高痫灶定位阳性率、准确性和灵敏度，表明亚临床发作期ＳＰＥＣＴ安全易行，能呈现ｒＣＢＦ增加，反映出发作期的显像特征     

Magnetic source imaging and ictal SPECT in MRI‐negative neocortical epilepsies: Additional value and comparison with intracranial EEG

Purpose: To investigate the utility of magnetic source imaging (MSI) and ictal single photon emission computed tomography (SPECT), each compared with intracranial electroencephalography (EEG) (ICEEG), to localize the epileptogenic zone (EZ) and predict epilepsy surgery outcome in patients with nonlesional neocortical focal epilepsy. Methods: Studied were 14 consecutive patients with nonlesional neocortical epilepsy who underwent presurgical evaluation including ICEEG, positive MSI, and localizing subtraction Ictal SPECT coregistered to MRI (SISCOM) analysis. Follow‐up after epilepsy surgery was ≥24 months. ICEEG, MSI, and SPECT results were classified using a sublobar classification. Key Findings: Of 14 patients, 6 (42.9%) became seizure‐free after surgery. Sublobar ICEEG focus was completely resected in 11 patients; 5 (45.5%) of them became seizure‐ free. Concordance of ICEEG and MSI and complete focus resection was found in 5 (35.7%) patients; 80% of them became seizure‐free. Sublobar ICEEG‐MSI concordance and complete focus resection significantly increased the chance of seizure freedom after epilepsy surgery (p = 0.038). In contrast, of the 6 patients (42.9%) with concordant ICEEG and SISCOM and complete focus resection, only 66.7% became seizure‐free (p = 0.138). Assuming concordant results, the additive value to ICEEG alone for localizing the EZ is higher with ICEEG‐MSI (odds ratio 14) compared to ICEEG‐SISCOM (odds ratio 6). Significance: This study shows that combination of MSI and/or SISCOM with ICEEG is useful in the presurgical evaluation of patients with nonlesional neocortical epilepsy. Concordant test results of either MSI or SISCOM with ICEEG provide useful additive information for that provided by ICEEG alone to localize the EZ in this most challenging group of patients. When sublobar concordance with ICEEG is observed, MSI is more advantageous compared to SISCOM in predicting seizure‐free epilepsy surgery outcome.     

Localization of epileptogenic zone in temporal lobe epilepsy by ictal scalp EEG.

Our aim was to evaluate the ability to localize the epileptogenic zone in temporal lobe epilepsy (TLE) by ictal scalp electroencephalogram (EEG). Using simultaneous video recording, we analysed scalp EEG activity during ictal periods in 38 patients (30 patients with medial TLE (MTLE) and eight with lateral TLE (LTLE)). In 14 patients, intracranial ictal EEGs were recorded with depth electrodes, and simultaneous recordings of scalp and intracranial EEG were performed in 11 patients. Scalp EEG showed that, in all 30 patients with MTLE (71 of 72 seizures), an attenuation of background activity was observed before the appearance of ictal activity. Ictal discharges first appeared in the scalp EEG when the ictal discharges reached the lateral part of the temporal lobe on the intracranial EEG. While, in all eight patients with LTLE (25 of 25 seizures), the attenuation of background activity did not occur before the appearance of ictal activity. When the ictal discharges started in the lateral temporal lobe on intracranial EEG, ictal discharges appeared on the scalp. MTLE and LTLE could be diagnosed by the presence or absence of attenuation of background activity with clinical ictal signs before the appearance of ictal discharges.     

Single Photon Emission Computed Tomography (SPECT) in a Patient with Bilateral Temporal Seizures: Correlation Between Ictal EEG and Postictal/Ictal SPECT

Summary: We report a patient with bilateral independent temporal lobe seizures in whom two [^99mTc]HMPAO single photon emission computed tomograph (SPECT) scans were performed during two different seizures. In the first perüctal SPECT, [^99mTc]HMPAO was injected in the interval between two closely spaced seizures (one localized in the left temporal lobe and the other in the right temporal lobe). SPECT images showed hypoperfusion in the left lateral temporal lobe, hyper-perfusion of the left mesial temporal region, and pronounced hyperperfusion in the right anterior temporal lobe. These results suggest both a postictal left temporal SPECT pattern and an ictal right temporal pattern. In the second periictal SPECT, [^99mTc]HMPA was injected immediately after a right temporal lobe seizure and showed right lateral temporal lobe hypoperfusion and right mesial hyperperfusion, suggesting a postictal right temporal SPECT pattern. Interpretation of the periictal SPECT should take into account EEG changes at the time or in the minutes immediately after injection of [^99mTc] HMPAO.     

Correlation between provoked ictal SPECT and depth recordings in adult drug-resistant epilepsy patients

PURPOSE: To correlate ictal hyperperfusion single-photon emission computed tomography (SPECT) area during provoked seizures to the epileptogenic zone (EZ), as defined by depth recordings in adult drug-resistant patients. METHODS: We included in the study eight drug-resistant epilepsy patients, subjected to both noninvasive and invasive (stereo-electroencephalography, SEEG) presurgical evaluation in the Epilepsy Surgery Center of the Catholic University in Rome, from 2001 to 2003. All patients were subjected to interictal and provoked ictal SPECT scans during scalp video-EEG monitoring. The ictal hyperperfusion area assessed by visual image analysis and, when possible, by statistical parametric mapping (SPM), was compared with the EZ, as assessed by SEEG, to define whether they colocalized. RESULTS: For each provoked seizure, we obtained a SPECT hyperperfusion area. In five patients, the SPECT hyperperfusion area was included in the EZ as assessed by SEEG. The effectiveness of provoked SPECT was confirmed by comparison with SEEG data, SPM analysis (four patients), and spontaneous ictal SPECT (two patients). Our data were obtained in adult drug-resistant epilepsy patients whose EZ was either located in or extended to extratemporal regions in all but two patients. CONCLUSIONS: Provoked ictal SPECT confirmed its efficacy and accuracy in the presurgical evaluation because of the colocalization to the EZ. Although the low number of patients precluded any statistical correlation with the surgical outcome, it is worth pointing out that the five patients in whom the hyperperfusion area was included in the EZ showed very satisfactory results.     

99Tcm-TRODAT-1 SPECT与131I-epideprideSPECT显像对早期帕金森病人的临床应用价值

目的探讨脑多巴胺转运体（DAT）^99Tc^m-TRODAT-1 SPECT显像与多巴胺D2受体（D2R）^131I-epidepride SPECT显像在早期帕金森病（PD）中的临床应用价值。方法10例正常对照者及46例早期未经替代治疗的PD患者分别接受脑DAT ^99Tc^m-TRODAT-1 SPECT与多巴胺D2R ^131I-epidepride SPECT断层显像，利用感兴趣区技术计算纹状体与枕叶、额叶的放射性比值（ST-OC／OC和ST-FC／FC）。结果PD患者起病肢体对侧脑DAT比值ST-OC／OC和ST-FC／FC比同侧均降低，双侧ST-OC／OC较对照组均降低。PD患者起病肢体对侧脑D2R比值ST-OC／OC和ST-FC／FC比同侧均增高。PD患者起病肢体对侧脑DAT比值ST-OC／OC与患者病程呈负相关，起病肢体对侧脑D2R比值ST-OC／OC与患者年龄及UPDRS运动评分呈负相关。结论人脑DAT ^99Tc^m-TRODAT-1 SPECT显像与D2R ^131I-epidepride SPECT显像均有助于PD的早期诊断及病情监测。     

PET对癫痫致痫区定位的研究进展

正电子发射型计算机断层显像（Positron Emission Computed Tomography ,PET ）是一种探测放射性示踪剂在体内分布及动态变化情况的显像技术,在神经功能影像学检查方法中,PET 目前被认为是癫痫外科术前评估的最佳无创性功能性影像检查方法［1］。 PET 利用不同种类的示踪剂,来探究脑组织葡萄糖代谢、氧代谢、脑血流灌注、神经受体分布、生化和蛋白合成等方面的变化,尤其对于结构影像学检查阴性的癫痫患者有很大的定位诊断价值［2－3］。