Additional Single Photon Emission Computed Tomography Research Articles

Current state of bone scintigraphy protocols and practice in Japan.

Nuclear medicine technologists in Japan often perform additional single-photon emission computed tomography (SPECT) with or without computed tomography (CT) after whole-body imaging for bone scintigraphy. In this study, we wanted to identify the bone scanning protocols used in Japan, together with the current clinical practices. The study was conducted between October and December 2017. We created a web survey that was hosted by the Japanese Society of Radiological Technology. The questionnaire included 12 items regarding the demographics of the responders, their scan protocols, and the imaging added to, or omitted from, routine protocols. In total, 228 eligible responses were collected from participants with a mean of 11.6±8.4 years' experience in nuclear medicine examination. All responders reported using routine scan protocols that included whole-body imaging. However, only 2%, 4%, 20%, and 14% of the responders also acquired single-field SPECT, single-field SPECT/CT, multi-field SPECT, and multi-field SPECT/CT, respectively. Our survey results indicate that nuclear medicine practice in Japan is beginning to shift from planar whole-body imaging with additional spot planar images to additional SPECT or SPECT/CT. Further study is required to examine the optimal protocols for bone scintigraphy.

Does SPECT Provide Incremental Value to CT or MRI in Assessing Mandibular Invasion by Oral Squamous Cell Carcinoma?

Single photon emission computed tomography (SPECT) has been commonly used as an additional method to assess mandibular bone invasion in patients with oral squamous cell carcinoma (OSCC). In the present study, we measured the diagnostic validity of SPECT findings compared with the histologic findings. We implemented a retrospective cross-sectional study and enrolled a sample of patients with OSCC adjacent to the mandible. The staging examinations included magnetic resonance imaging (MRI) and/or computed tomography (CT) and additional SPECT. The patients' medical records and imaging data were reviewed by 2 readers, and bone invasion was classified as positive or negative for each diagnostic method. The predictor was bone invasion found on CT and/or MRI compared with the combination of CT and/or MRI with either positive or negative SPECT results. The primary outcome variable was histologic bone invasion. Other variables of interest were clinicopathologic data, type of mandibular resection, and resection margin status. Bivariate tests were used to compare the diagnostic specificity, sensitivity, and accuracy of each imaging modality. The study enrolled 122 patients, with a mean age of 67years (55% male; study period, January 2010 to December 2017). In 60 patients (49%), segmental mandibular resection was performed. The sensitivity and specificity for bone invasion were 100% and 39% for SPECT and 84% and 75% for CT and/or MRI. The negative results for bone invasion using SPECT did not match the false-positive CT and/or MRI results in 5% (n=6 of 122). Positive SPECT findings, in addition to positive CT and/or MRI findings increased the sensitivity to 100% but decreased the specificity to 29% (P<.001). Considering only negative SPECT findings increased the specificity to 85% (P=.03), sensitivity remaining unaffected. The accuracy of CT and/or MRI alone was 80% and was 84% when combining CT and/or MRI and negative SPECT findings (P=.03). In oncologic staging with CT and/or MRI, the addition of SPECT provided only small benefits. Only negative SPECT results allowed for greater specificity and accuracy. The use of SPECT could be considered to rule out bone invasion in cases of radiologic uncertainty of positive CT or MRI findings.

P090] Optimalization of quantification of mandibular growth

Purpose Excessive growth of one condyle suspected of active unilateral condylar hyperplasia (UCH) may lead to asymmetric facial deformities and malocclusion. Single photon emission computed tomography (SPECT) bone scintigraphy is becoming current global standard for diagnostic of UCH. The examination is performed after intravenous administration of radioactive technetium-labelled diphosphates (99mTc-MDP). The aim of this research is to select the most suitable method for the evaluation of asymmetry and mandibular growth in comparison with the normal values. Methods 17 patients were evaluated (11 represent normal values, 6 patients with UCH). No patient from normal database had a previous history of growth abnormality or pathological condition involving the maxillofacial skeleton or mandible. These patients underwent an additional mandibular SPECT to create a normal database. Except the asymmetry, mandibular growth was also examined. The internal (clivus) and external standard (source of known activity) was used to evaluate the growth. The region and volume of interest (ROI/VOI) across each condyle and clivus were drawn by various methods. For each ROI/VOI, the total number of counts, maximum and average values in ROI/VOI and their size were recorded. Results The correlation analysis suggested that it is inappropriate to substitute the values obtained from different sizes of ROI for one another. The ratio of the right and left condyle may be used to evaluate the mandibular asymmetry. For the evaluation of the growth activity of condyle is necessary to use standardization. Therefore, external standard located near patient head is the most appropriate approach. The evaluation method and criteria were determined by the analyses. Conclusions The use of 99mTc-MDP SPECT appears to be a suitable quantitative method for assessing the growth activity of the mandible. The average counts in same size of ROI and usage of external standardization appears to be most suited method for assessing the growth activity of a condyle. Similar conclusion holds for assessing asymmetric growth. However, it is still necessary to monitor these parameters and criteria and adapt them on the basis of a wider database of normal values.

Use of quantitative SPECT/CT reconstruction in 99mTc-sestamibi imaging of patients with renal masses.

Technetium-99m (99mTc)-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has previously been shown to allow for the accurate differentiation of benign renal oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) apart from other malignant renal tumor histologies, with oncocytomas/HOCTs showing high uptake and renal cell carcinoma (RCC) showing low uptake based on uptake ratios from non-quantitative single-photon emission computed tomography (SPECT) reconstructions. However, in this study, several tumors fell close to the uptake ratio cutoff, likely due to limitations in conventional SPECT/CT reconstruction methods. We hypothesized that application of quantitative SPECT/CT (QSPECT) reconstruction methods developed by our group would provide more robust separation of hot and cold lesions, serving as an imaging framework on which quantitative biomarkers can be validated for evaluation of renal masses with 99mTc-sestamibi. Single-photon emission computed tomography data were reconstructed using the clinical Flash 3D reconstruction and QSPECT methods. Two blinded readers then characterized each tumor as hot or cold. Semi-quantitative uptake ratios were calculated by dividing lesion activity by background renal activity for both Flash 3D and QSPECT reconstructions. The difference between median (mean) hot and cold tumor uptake ratios measured 0.655 (0.73) with the QSPECT method and 0.624 (0.67) with the conventional method, resulting in increased separation between hot and cold tumors. Sub-analysis of 7 lesions near the separation point showed a higher absolute difference (0.16) between QPSECT and Flash 3D mean uptake ratios compared to the remaining lesions. Our finding of improved separation between uptake ratios of hot and cold lesions using QSPECT reconstruction lays the foundation for additional quantitative SPECT techniques such as SPECT-UV in the setting of renal 99mTc-sestamibi and other SPECT/CT exams. With robust quantitative image reconstruction and biomarker analysis, there may be an expanded role for SPECT/CT imaging in renal masses and other pathologic conditions.

Preoperative imaging for focused parathyroidectomy: making a good strategy even better.

Surgical treatment for primary hyperparathyroidism (pHPT) has undergone a major paradigm shift during the last decades from bilateral cervicotomy with four-gland neck exploration to image-guided focused approaches. The primary objective of the present study was to compare the performances of parathyroid scintigraphy (PS), parathyroid ultrasonography (US), and the combination of both procedures for guiding a focused approach on the basis of modified interpretation criteria. Data from 199 patients operated for apparent sporadic pHPT and evaluated with US and PS using dual-isotope (123)I/(99m)Tc-sestamibi planar pinhole and single-photon emission computed tomography (SPECT) acqusitions were evaluated. A total of 127 patients underwent a focused approach and the remainder had bilateral cervicotomy. In 42 cases, a focused approach was not performed due to the absence of concordant results between US and PS for a single-gland abnormality. Four patients had persistent disease and three had recurrent disease. A localizing preoperative PS had a sensitivity of 93.3%, positive predictive value of 85.8%, negative predictive value of 73.0%, and accuracy of 83.4% for predicting uniglandular disease. Additional SPECT images accurately localize posterior adenomas that are often missed by US. Compared with PS, US had a lower sensitivity (P<0.01). Our imaging protocol also enabled diagnosis of multiglandular disease in 60.6%. PS using a highly sensitive dual-tracer subtraction method is the most accurate technique for directing a focused approach. PS could be sufficient for directing a focused approach in the presence of a negative US in two major circumstances: posterior locations due to acquired ectopia that could be missed by US, and previous history of thyroidectomy due to interpretation difficulties.

P2-09-01: First-in-Human Whole-Body HER2−Receptor Mapping Using Affibody Molecular Imaging.

Abstract Background: ABY-025 is a member of a promising class of scaffold-based antibody alternatives known as Affibody molecules with superior properties for molecular imaging compared to monoclonal antibodies. It is a minimal-size, high-affinity HER2 binder, noncompetitive with trastuzumab allowing imaging even during trastuzumab therapy. This pilot clinical study set out to establish a safe clinical procedure for further tests and to verify whether breast cancer lesions could be identified and characterized for HER2 expression using single-photon emission computed tomography (SPECT) imaging. Patients and methods: Seven patients with metastatic breast cancer, five with HER2 positive primary tumors and two HER2 negative controls were included. A standard 3-hour 18F-FDG-PET was performed to locate the lesions and 5 days later an injection with 111Inlabeled ABY-025 was given followed by whole body scanning at 30 minutes with additional SPECT at 4, 24 and 48 hours. Biopsies were taken from amenable lesions and analyzed by immunohistochemistry to verify the HER2 status. Results: Large metastases were visualized already at 30 minutes and at later registrations a majority of all known lesions could be identified. A brain metastasis showed exceptionally high HER2 signal-to-background-ratio. Two fundamental behaviors were observed: High tumor to background ratio, increasing over time, was predominant in the HER2−positive group while the HER2−negative group generally presented a lower ratio. One patient in the positive group unexpectedly showed low tumor to background ratio similar to the negative group. Biopsy verified that the initially positive patient had converted to low HER2 expression. All other biopsies confirmed that the metastases were still positive or negative in line with the subject's primary lesions. None of the subjects had any adverse reactions due to the investigations. Conclusion: ABY-025 can be used safely in humans with similar excellent whole body HER2−receptor molecular imaging capabilities as have already been observed in animal models. Promising indications of in vivo HER2−receptor status discriminatory capabilities were observed. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-09-01.

Wide beam reconstruction for half-dose or half-time cardiac gated SPECT acquisitions: optimization of resources and reduction in radiation exposure

A new iterative reconstruction algorithm (WBR™) has been recently proposed for cardiac single photon emission computed tomography (SPECT). The WBR™ technology is designed to reduce noise, improving lesion identification without affecting the image resolution, allowing SPECT studies with reduced count statistic. This allows for either half-time (HT) or half-dose (HD) cardiac SPECT, with image quality and quantitative data comparable to standard-time (ST) or standard-dose (SD) SPECT. Few data exist on the comparison between conventional filtered backprojection (FBP) and this new algorithm in a clinical setting. The aim of this study was to compare the performance of FBP and WBR™. Phantoms studies were performed to compare spatial resolution and contrast recovery with FBP, ordered subset expectation maximization (OSEM) and WBR™. A group of 92 patients, with different cardiac pathology, scheduled for a stress-rest SPECT were studied: 52 patients (group A) were injected with a SD of tracer and underwent both ST and HT SPECT; 40 patients (group B) were injected with a half dose of tracer and underwent ST SPECT and immediately after an additional SPECT at double time/projection (DT), to compensate for the low count statistic. A 2-day (99m)Tc-sestamibi protocol was used in all patients. SD/ST and HD/DT SPECT were reconstructed with a conventional FBP; SD/HT and HD/ST SPECT were reconstructed with WBR™. The summed stress score (SSS) and summed rest score (SRS) were calculated; the left ventricular ejection fraction (LVEF) was automatically derived. In group A (SD), no significant differences were observed between ST FBP SPECT and HT WBR™ in SSS (11.1 and 11.7, respectively) and SRS (9.4 and 10.3, respectively, NS). LVEF on rest acquisitions was also comparable (50% on ST SPECT and 49% on HT SPECT, NS); LVEF on post-stress studies in HT SPECT (46%) was lower than ST SPECT (50%), although not statistically significant. In group B (HD), SSS (6.2 in ST and 5.3 in DT) and SRS (4.0 in ST and 3.3 in DT) were also comparable. No differences were documented between ST and DT in rest (47 and 48%, respectively) and stress (48 and 50%, respectively) LVEF. WBR™ performance and image quality were comparable to those of conventional FBP, allowing for either HT or HD studies. The former allows for an increased patient throughput and optimization of resources. The latter modalities would allow for a significant reduction in both patients' and operators' exposure. Further studies are needed to validate the clinical use of this method.

Accuracy of parathyroid imaging: comparison of planar scintigraphy, spect, spect/ct and c-11 methionine pet for the detection of parathyroid adenomas and glandular hyperplasia

To compare the accuracy of planar scintigraphy, single photon emission computed tomography (SPECT), SPECT-CT, and positron emission tomography (PET) with C-11 methionine for the pre-operative detection of parathyroid adenomas. We retrospectively evaluated the pre-operative studies of 60 patients with primary (n=56) and secondary (n=4) hyperparathyroidism. In 25/60 patients (Group 1), only planar scans were obtained, and additional SPECT and SPECT-CT were carried out in 35/60 patients (Group 2). PET or PET-CT with C-11 methionine was conducted in 8/60 patients (Group 3). The results of the planar scans (Group 1) were true positive in 19/25 patients and false negative in 6/25 patients (sensitivity per patient, 76%). Histopathology confirmed 27 adenomas and two hyperplasia. Planar imaging identified 20/29 of these pathologies, whereas 9/29 were missed (sensitivity per adenoma, 69%). SPECT (Group 2) results were true positive in 34/35 patients and false negative in only one case (sensitivity per patient, 97%). On a lesion-based analysis, 38 adenomas were identified, and two were missed (sensitivity per adenoma, 95%). The sensitivities of SPECT and SPECT-CT were equal; however, SPECT-CT provided superior topographic information. C-11 methionine PET (Group 3) results were true positive in all eight patients. In one case, surgery confirmed two ipsilateral adenomas, only one of which was identified by PET (sensitivity per patient, 100%; per adenoma, 88.9%). SPECT is superior to planar imaging. SPECT-CT has identical sensitivity compared to SPECT alone, but it provides additional topographic information. The sensitivity of PET appears to be even higher compared to SPECT. In the case of negative scintigraphic findings and proven hyperparathyroidism, additional C-11 methionine PET or PET-CT is recommended.

Use of 99mTc-MDP SPECT for assessment of mandibular growth: development of normal values

Planar scintigraphy using (99m)Tc-labeled methylene diphosphonate ((99m)Tc-MDP) has been established as a method for evaluating mandibular growth and asymmetry. However, (99m)Tc-MDP single photon emission computed tomography (SPECT) provides improved image contrast and quantitative capability potentially allowing the clinician to make a more accurate assessment of the stage of activity of normal and asymmetric mandibular growth. The purpose of this study was to utilize (99m)Tc-MDP SPECT in normal subjects to develop a standardized approach to imaging the mandible that could subsequently be used to evaluate patients with potential for mandibular growth abnormalities. Thirty-two patients (22 females, 10 males, 8-25 years of age, mean of 14 years) having (99m)Tc-MDP bone scans (7.4 MBq/kg, maximum of 518 MBq) for indications not involving the head were asked to have an additional SPECT that included the mandibular condyles. Internal (clivus) and external (source of known activity included within the field of view) standards were both investigated. Two- and three-dimensional (2-D and 3-D) regions of interest (ROI) were drawn over each condyle and the clivus in a single slice containing the maximum pixel value within the structure. A 3-D ROI was also drawn about the external standard. Maximum and average pixel values within the 2-D and 3-D ROIs were recorded. Correlation analysis indicated that essentially the same information was obtained whether the maximum or average pixel value within a 2-D or 3-D ROI was used. The right to left ratio provided a parameter that can be used to assess the magnitude of mandibular metabolic asymmetry. Use of an external standard provides the potential for quantifying condylar uptake for assessment of the activity of mandibular growth. Normal ranges for different age groups were determined for condylar uptake using both internal and external standards. (99m)Tc-MDP SPECT provides a quantitative method for assessing mandibular condylar uptake as a reflection of the activity of mandibular growth. The maximum pixel value of a 2-D ROI using external standardization and the right to left ratio of the condylar uptake provide the potential for quantitative evaluation of patients with mandibular asymmetry. These parameters will be further evaluated in an upcoming clinical investigation.

Impact of additional SPECT in bone scanning in tumor patients with suspected metastatic bone disease

The aim of this study was to investigate the additional value of single-photon emission computed tomography (SPECT) for patient staging compared to planar bone scanning in an unselected cohort of cancer patients. The study included 271 consecutive tumor patients in whom planar imaging and two-bed position SPECT of the spine and the pelvis had been performed. Retrospective image interpretation was performed independently for planar and SPECT scans. Findings were categorized as 'benign', 'equivocal', or 'malignant' on a lesion base, and as 'no metastatic disease', 'equivocal', or 'metastatic disease' on a patient base. 447 lesions were detected by SPECT. Missing of lesions in planar images was rare (4.3% of all SPECT lesions). Planar findings differed from SPECT findings in 149 lesions (33.3%). Most of these 'inconsistent' lesions were rated as equivocal in the planar images but benign (14.5% of all lesions) or malignant (11.0%) by SPECT. On a patient base, 81.6% of patients with planar equivocal staging were classified as either benign (55.3%) or malignant (26.3%) by SPECT. Patients definitively staged as 'no metastatic disease' or 'metastatic disease' in planar images were staged differently by SPECT in only 3.7% of cases (up-staging in 2.6% and down-staging in 1.1%). Single-photon emission computed tomography changed a definite staging as based on planar images in less than 4% of the patients. In patients with planar equivocal staging, however, SPECT allowed a definite diagnosis in more than 80% of these cases, and, thus, should be performed routinely in patients with equivocal findings.

Thalamic and limbic involvement in the mechanism of action of vagus nerve stimulation, a SPECT study

To unravel the mechanism of action of neurostimulation as a treatment for seizures, functional neuroimaging tools allow minimally invasive research in humans. We performed single-photon emission computed tomography (SPECT) in patients with epilepsy, treated with vagus nerve stimulation (VNS). Changes in regional cerebral blood flow (rCBF) at the time of initial stimulation as well as after chronic treatment were correlated with long-term clinical efficacy. In this pilot study, 27 patients (14 female and 13 male) who were treated with VNS at Ghent University Hospital for refractory epilepsy underwent a (99m)Tc-ECD (ethyl cystein dimer) SPECT activation study at the time the first stimulation train was administered. 12 patients underwent an additional (99m)Tc-ECD SPECT activation study 6 months later. Image acquisition was performed on a high-resolution triple-headed gamma camera. Significant rCBF changes were correlated with prospectively assessed clinical efficacy data. Significant rCBF changes were found in the thalamus, the hippocampus and the parahippocampal gyrus. Acute limbic hyper-perfusion and chronic thalamic hypo-perfusion correlate with positive clinical efficacy. Acute and chronic electrical stimulation of the vagus nerve induces rCBF changes that can be measured by SPECT on a group-basis. The thalamus and the limbic system are thought to play a key role in the mechanism of action of VNS.

Musical brains: a study of spontaneous and evoked musical sensations without external auditory stimuli

Conclusions. Our observations confirm that musical sensations with no external stimuli, either spontaneous or evoked, occur in normal individuals and that a biological substrate can be demonstrated by brain single photon emission computed tomography (SPECT). Objectives. There are individuals, usually musicians, who are seemingly able to evoke and/or have spontaneous musical sensations without external auditory stimuli. However, to date there is no available evidence to determine if it is feasible to have musical sensations without using external sensory receptors, or if there is a biological substrate for these sensations. Subjects and methods. A group of 100 musicians and another of 150 otolaryngologists were asked if they had spontaneous musical auditory sensations and/or were capable of evoking them. SPECT evaluations with Tc99m-HMPAO were conducted in six female musicians while they were evoking these sensations or, in one case, while she was having them spontaneously. In three of them an additional SPECT was conducted in basal conditions (having been asked to avoid evoking music).Results. In all, 97 of 100 musicians had spontaneous musical sensations; all 100 could evoke and modify them. Of the 150 otolaryngologists, 18 (12%) were musicians. Of the 132 nonmusicians, spontaneous musical sensations occurred in 52 (39.4%), 72 (54.5%) could evoke and 23 (17.4%) were able to modify them, 58 (43.9%) did not have spontaneous musical sensations nor could they evoke them. The musical sensations of the 72 otolaryngologists that could evoke were less elaborated than those of musicians. NeuroSPECT during voluntary musical autoevocation demonstrated significant (>2 SD) increased activation of executive frontal cortex in Brodmann areas 9 and 10, secondary visual cortex (area 17), and paracingulate (areas 31 and 32). There was also activation in the para-executive frontal cortex (areas 45 and 46). In the basal ganglia there was activation in thalamus and lentiform nucleus. Deactivation below 2 SD was demonstrated by mean values in the cingulate gyrus, Brodmann areas 23 and 24, and subgenual area 25. Deactivation was also demonstrated when minimal values were analyzed in the same areas plus area 4 and areas 36 and 38, the latter in the pole of the temporal lobes. In three patients comparison of basal state with autoevocation demonstrated activation in executive frontal cortex (areas 8 and 9), para-executive cortex (area 45), primary auditory cortex (area 40), the right thalamus, and lentiform nucleus.

Optimizing preoperative imaging in primary hyperparathyroidism

Scintigraphy of the hyperfunctioning parathyroid glands using technetium 99m ((99m)Tc)-methoxyisobutylisonitrile ((99m)Tc-MIBI) is an established and highly sensitive preoperative localization tool whose importance has been further increased by advances in minimally invasive surgery . The goal of the present prospective study was to determine the benefit of optimized imaging in a consistent patient population. Eighty-four patients with first presentations of primary hyperparathyroidism were investigated with (99m)Tc-MIBI scintigraphy, thyroid scintigraphy, and cervical ultrasonography. The evaluation algorithm consisted of (a) evaluation of the planar images alone, (b) additional evaluation of single-photon emission computed tomography (SPECT), (c) additional evaluation of thyroid gland scintigraphy, and (d) additional evaluation of ultrasound. All patients subsequently underwent parathyroidectomy. The intraoperative and the histologic findings were correlated with the results of the scintigraphic imaging. The sensitivity of planar parathyroid scintigraphy was 74% and could be increased to 91% by the additional investigations. The difference was statistically significant (p<0.05). At the same time, a small increase in specificity from 96% to 99% was seen. Prior to minimally invasive treatment of hyperparathyroidism, we recommend combined localization studies consisting of sequential (99m)Tc-MIBI scintigraphy, additional SPECT plus thyroid gland scintigraphy, plus high-resolution cervical ultrasonography.

Diffusion-Weighted Imaging: Can it Play a Role in the Evaluation of Patients with Epilepsy?

Diffusion-Weighted and Perfusion MRI Demonstrates Parenchymal Changes in Complex Partial Status Epilepticus Szabo K, Poepel A, Pohlmann-Eden B, Hirsch J, Back T, Sedlaczek O, Hennerici M, Gass A Brain 2005;128(Pt 6):1369–1376 Diffusion-weighted MRI (DWI) and perfusion MRI (PI) have been mainly applied in acute stroke, but may provide information in the peri-ictal phase in epilepsy patients. Both transient reductions of brain water diffusion, namely a low apparent diffusion coefficient (ADC), and signs of hyperperfusion have been reported in experimental and human epilepsy case studies. We studied 10 patients with complex partial status epilepticus (CPSE) with serial MRI, including DWI and PI. All patients showed regional hyperintensity on DWI, and a reduction of the ADC in (i) the hippocampal formation and the pulvinar region of the thalamus (six out of 10 patients), (ii) the pulvinar and cortical regions (two out of 10), (iii) the hippocampal formation only (one out of 10), and (iv) the hippocampal formation, the pulvinar and the cortex (one out of 10). In all patients, a close spatial correlation of focal hyperperfusion with areas of ADC/DWI change was present. In two patients, hyperperfusion was confirmed in additional SPECT (single photon emission computed tomography) studies. All patients received follow-up MRI examinations showing partial or complete resolution of diffusion and perfusion abnormalities depending on the length of the follow-up interval. The clinical course, EEG, and SPECT results all indicate that MRI detected changes related to prolonged epileptic activity. Combined PI and DWI can visualize haemodynamic and tissue changes after CPSE in the hippocampus, thalamus, and affected cortical regions.

Diffusion-weighted and perfusion MRI demonstrates parenchymal changes in complex partial status epilepticus

Diffusion-weighted MRI (DWI) and perfusion MRI (PI) have been mainly applied in acute stroke, but may provide information in the peri-ictal phase in epilepsy patients. Both transient reductions of brain water diffusion, namely a low apparent diffusion coefficient (ADC), and signs of hyperperfusion have been reported in experimental and human epilepsy case studies. We studied 10 patients with complex partial status epilepticus (CPSE) with serial MRI including DWI and PI. All patients showed regional hyperintensity on DWI, and a reduction of the ADC in (i) the hippocampal formation and the pulvinar region of the thalamus (six out of 10 patients), (ii) the pulvinar and cortical regions (two out of 10), (iii) the hippocampal formation only (one out of 10), and (iv) the hippocampal formation, the pulvinar and the cortex (one out of 10). In all patients a close spatial correlation of focal hyperperfusion with areas of ADC/DWI change was present. In two patients hyperperfusion was confirmed in additional SPECT (single photon emission computed tomography) studies. All patients received follow-up MRI examinations showing partial or complete resolution of diffusion and perfusion abnormalities depending on the length of the follow-up interval. The clinical course, EEG and SPECT results all indicate that MRI detected changes related to prolonged epileptic activity. Combined PI and DWI can visualize haemodynamic and tissue changes after CPSE in the hippocampus, thalamus and affected cortical regions.

Diagnostic imaging in abdominal neuroblastoma: is there a complementary role of MIBG-scintigraphy and ultrasonography?

In a retrospective study we evaluated the agreement between the results of meta-iodo benzylguanidine (MIBG) scintigraphy and abdominal ultrasonography (US) in the diagnosis and follow up of neuroblastoma (NBL) with respect to the abdominal region. Data of 28 consecutive paediatric patients with NBL or suspected NBL were included (16 M/12 F, mean age 2.9 years, range 3 weeks-13.4 years). The results (as judged by the nuclear physician or radiologist, respectively) of 60 MIBG examinations (123I and 131I) including 26 single photon emission computed tomography (SPECT) and US, respectively, performed within a period of 14 days, could be evaluated. Full agreement was reached in 37 comparisons (62%), while partial and no agreement was found in 17 (28%), and 6 (10%) comparisons respectively. In 8 out of 37 comparisons with full agreement, 12 diagnosed lesions were histopathologically proven, while 11 comparisons with negative findings were also negative in other clinical modalities. US diagnosed correctly in 68% of the histopathological proven lesions, while this was 54% for MIBG scintigraphy. In approximately 50% of the MIBG scans in which SPECT was available, SPECT provided significant additional information. Congruent results of MIBG scintigraphy and ultrasonography in the detection of abdominal lesions in patients with suspected neuroblastoma indicate a high reliability in the diagnosis and localisation. Due to the favourable results of additional SPECT, it is advisable to perform SPECT routinely in this diagnosis.