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Background and purpose GTV definition for re-irradiation treatment planning in recurrent glioblastoma (rGBM) is usually based on contrast-enhanced MRI (GdT1w-MRI) and, for an increased specificity, on amino acid PET. Diffusion-weighted (DWI) MRI and ADC maps can reveal regions of high cellularity as surrogate for active tumor. The objective of this study was to compare the localization and quality of diffusion restriction foci (GTV-ADClow) with FET-PET (GTV-PET) and GdT1w-MRI (GTV-GdT1w-MRI). Material and methods We prospectively evaluated 41 patients, who received a fractionated stereotactic re-irradiation for rGBM. GTV-PET was generated automatically (tumor-to-background ratio 1.7–1.8) and manually customized. GTV-ADClow was manually defined based on DWI data (3D diffusion gradients, b = 0, 1000 s/mm2) and parametric ADC maps. The localization of recurrence was correlated with initial GdT1w-MRI and PET data. Results In 30/41 patients, DWI-MRI showed areas with restricted diffusion (mean ADC-value 0.74 ± 0.22 mm2/s). 66% of GTVs-ADClow were located outside the GdT1w-MRI volume and 76% outside increased FET uptake regions. Furthermore, GTVs-ADClow were only partially included in the high dose volume and received in mean 82% of the reference dose. An adjusted volume including GdT1w-MRI, PET-positive and restricted diffusion areas would imply a GTV increase of 48%. GTV-PET and GdT1w-MRI correlated better with the localization of re-recurrence in comparison to GTV-ADClow. Conclusion Unexpectedly, GTV-ADClow overlapped only partially with FET-PET and GdT1w-MRI in rGBM. Moreover, GTV-ADClow correlated poorly with later rGBM-recurrences. Seeing as a restricted diffusion is known to correlate with hypercellularity, this imaging discrepancy could only be further explained in histopathological studies.

Background We hypothesized that dominant intraprostatic lesions (DILs) could be depictured by multimodal imaging techniques (MRI and/or PSMA PET/CT) in patients with primary prostate cancer (PCa) and investigated possible effects of radiotherapy (RT) dose distribution within the DILs on the patients’ outcome. Methods One hundred thirty-eight patients with localized prostate cancer (PCa) and visible DIL underwent primary external beam RT between 2008 and 2016 with an aimed prescription dose of 76 Gy to the whole prostate. Seventy-five patients (54%) additionally received androgen deprivation therapy. Three volumes were retrospectively generated: DIL using pretreatment MRI and/or PSMA PET/CT, prostatic gland (PG) and the subtraction between PG and DIL (SPG). The minimum dose (Dmin), maximum dose (Dmax) and mean dose (Dmean) in the three respective volumes were calculated. Biochemical recurrence free survival (BRFS) was considered in uni- and multivariate Cox regression analyses. An explorative analysis was performed to determine cut-off values for the three dose parameters in the three respective volumes. Results With a median follow-up of 45 months (14–116 months) 15.9% of patients experienced BR. Dmin (cut-off: 70.6 Gy, HR = 0.39, p = 0.036) applied to the DIL had an impact on BRFS in multivariate analysis, in contrast to the Dmin delivered to PG and SPG which had no significant impact (p > 0.05). Dmin was significantly (p 0.05). Conclusions The dose distribution within DILs defined by PSMA PET/CT and/or MRI is an independent risk factor for BR after primary RT in patients with PCa. These findings support the implementation of imaging based DIL interpretation for RT treatment planning, although further validation in larger patient cohorts with longer follow-up is needed.

Prostate-specific membrane antigen (PSMA) PET/CT detects prostate cancer recurrence at low levels of prostate-specific antigen (PSA). Radiotherapy with dose escalation to the former prostate bed has been associated with improved biochemical recurrence-free survival (BRFS). Thus, we hypothesized that PSMA PET/CT-guided salvage radiotherapy leads to improved BRFS. Methods: In total, 204 consecutive patients were referred for salvage radiotherapy after radical prostatectomy. PSMA PET/CT scans were performed, and patients with PSA persistence (109 patients) or evidence of distant metastases (5 patients) were excluded from this analysis. Thus, the following analysis is based on a total of 90 patients who underwent PSMA PET/CT before radiotherapy due to biochemical recurrence and received salvage radiotherapy. In cases of PET-positive findings, antiandrogen therapy was commenced before initiation of radiotherapy. BRFS (PSA ≤ 0.2 ng/mL) was defined as the study endpoint. Results: PET-positive lesions were detected in 42 of 90 (47%) patients, 24 of 42 (27%) being fossa recurrence only, 12 of 42 (13%) pelvic lymph node only, and 6 of 42 (7%) both fossa and pelvic lymph node. The median PSA before radiotherapy was 0.44 ng/mL (range, 0.11–6.24 ng/mL). Cumulatively, a total dose of 70.0 Gy (range, 67.2–72 Gy) was delivered to local macroscopic tumor, 66 Gy (range, 59.4–70.2 Gy) to the prostatic fossa, 60.8 Gy (range, 54–66 Gy) to PET-positive lymph nodes, and 50.4 Gy (range, 45–50.4 Gy) to the lymphatic pathways. After a median follow-up of 23 mo, BRFS was 78%. Antiandrogen therapy was ongoing in 4 patients at the last follow-up. No significant difference in BRFS between PET-positive patients (74%) and PET-negative patients (82%; P > 0.05) was observed at the last follow-up. Two patients had late genitourinary toxicity, grade 3, and no patient had gastrointestinal toxicity of grade 3 or higher (National Cancer Institute common terminology criteria for adverse events, version 4.03). Conclusion: PSMA PET/CT-guided salvage radiotherapy is an effective and safe local treatment option. No difference in BRFS between PET-positive and PET-negative patients was observed, indicating effective targeting of PET-positive lesions. PSMA PET/CT when readily available should be offered to patients with PSA recurrence for treatment individualization.

Intraoperative identification of lymph node (LN) metastases (LNM) detected on preoperative PSMA PET/CT may be facilitated by PSMA radioguided surgery with the use of a gamma probe. We evaluated the uptake ofSix patients with prostate cancer (PCa) with suspicion of LNM on preoperative PSMA PET/CT underwentOverall 310 LN (mean 52 ± 19.7) were removed from 74 subregions (mean 12 ± 3.7). Of the 310 LN, 35 turned out to be LNM on histopathology. Separation of the samples from all subregions resulted in 318 single specimens: 182 PCa-negative LN samples with 275 LN, 35 single LNM samples, 3 non-nodal PCa tissue samples and 98 fibrofatty tissue samples. The median SULs of nonaffected LN (0.16) and affected LN (13.2) were significantly different (p 0.0001). Based on 38 tumour-containing and 182 tumour-free specimens, ROC analysis revealed an area under the curve of 0.976 (95% CI 0.95-1.00, p 0.0001). Using a SUL cut-off value of 1.136, sensitivity, specificity, positive predictive value, negative predictive value and accuracy in discriminating affected from nonaffected LN were 92.1% (35/38), 98.9% (180/182), 94.6% (35/37), 98.4% (180/183) and 97.7% (215/220), respectively.Ex situ analysis at the level of single LN showed that

The identification of pathological atrophy in MRI scans requires specialized training, which is scarce outside dedicated centers. We sought to investigate the clinical usefulness of computer-generated representations of local grey matter (GM) loss or increased volume of cerebral fluids (CSF) as normalized deviations (z-scores) from healthy aging to either aid human visual readings or directly detect pathological atrophy. Two experienced neuroradiologists rated atrophy in 30 patients with Alzheimer's disease (AD), 30 patients with frontotemporal dementia (FTD), 30 with dementia due to Lewy-body disease (LBD) and 30 healthy controls (HC) on a three-point scale in 10 anatomical regions as reference gold standard. Seven raters, varying in their experience with MRI diagnostics rated all cases on the same scale once with and once without computer-generated volume deviation maps that were overlaid on anatomical slices. In addition, we investigated the predictive value of the computer generated deviation maps on their own for the detection of atrophy as identified by the gold standard raters. Inter and intra-rater agreements of the two gold standard raters were substantial (Cohen's kappa κ > 0.62). The intra-rater agreement of the other raters ranged from fair (κ = 0.37) to substantial (κ = 0.72) and improved on average by 0.13 (0.57, Highlights • The visual identification of atrophy is most accurate in the temporal lobe. • Voxel-wise deviations of tissue volume from normal aging is easy to implement. • Displaying voxel-wise deviations subjectively but not objectively aids readers. • Voxel-wise deviations themselves show high agreement with expert readings. • Information on tissue deviations should be provided with cerebral MRI scans.

We investigated if sleep deprivation (SD) and electroconvulsive therapy (ECT) affect striatal dopamine transporter (DAT) availability assessed by single-photon emission computed tomography (SPECT) and

Moyamoya disease is a steno-occlusive disease of the circle of Willis with growth of pathologic collaterals. We compared functional perfusion imaging ([We performed a retrospective blinded analysis of individual imaging modalities (MRI, angiography, PET) and scored each modality for severity of disease in 21 untreated patients with moyamoya with 78 affected vascular territories.Positive predictive value to identify insufficient perfusion on angiography and MRI together was 98.3% as proven on combined PET/computed tomography. Negative predictive value to identify sufficient perfusion on angiography and/or MRI only was 60%. Negative predictive value to predict good perfusion on PET based on MRI (no infarctions in the respective territory) was only 17%. An assumed good perfusion based on the suggestion of good collaterals on angiography was correct in only 13.4% of cases. Positive predictive value (angiography of main vessel and weak or no collateralization) to predict insufficient perfusion on PET/computed tomography was 76.9%; negative predictive value (angiography of main vessel and strong collateralization) to identify good perfusion was 13.4%.Reliable evaluation of cerebral blood flow might not be possible with angiography and basic MRI alone. We strongly recommend additional functional imaging (e.g., [

Objective Methods To estimate the prevalence of amyloid positivity, defined by positron emission tomography (PET)/cerebrospinal fluid (CSF) biomarkers and/or neuropathological examination, in primary progressive aphasia (PPA) variants. We conducted a meta-analysis with individual participant data from 1,251 patients diagnosed with PPA (including logopenic [lvPPA, n = 443], nonfluent [nfvPPA, n = 333], semantic [svPPA, n = 401], and mixed/unclassifiable [n = 74] variants of PPA) from 36 centers, with a measure of amyloid-beta pathology (CSF [n = 600], PET [n = 366], and/or autopsy [n = 378]) available. The estimated prevalence of amyloid positivity according to PPA variant, age, and apolipoprotein E (ApoE) epsilon 4 status was determined using generalized estimating equation models. Results Interpretation Amyloid-beta positivity was more prevalent in lvPPA (86%) than in nfvPPA (20%) or svPPA (16%; p

PURPOSE: Intraoperative identification of lymph node (LN) metastases (LNM) detected on preoperative PSMA PET/CT may be facilitated by PSMA radioguided surgery with the use of a gamma probe. We evaluated the uptake of 111In-labelled PSMA ligand DKFZ-617 (referred to as 111In-PSMA-617) in unaffected LN and LNM at the level of single LN. METHODS: Six patients with prostate cancer (PCa) with suspicion of LNM on preoperative PSMA PET/CT underwent 111In-PSMA-617-guided lymphadenectomy (LA; four salvage LA and two primary LA). 111In-PSMA-617 (109 ± 5 MBq). was injected Intravenously 48 h prior to surgery Template LAs were performed in small subregions: common, external, obturator and internal iliac vessels, and presacral and retroperitoneal subregions (n = 4). Samples from each subregion were isolated aiming at the level of single LN. Uptake was measured ex situ using a germanium detector. Receiver operating characteristic (ROC) analysis was performed based on 111In-PSMA-617 uptake expressed as standardized uptake values normalized to lean body mass (SUL). RESULTS: Overall 310 LN (mean 52 ± 19.7) were removed from 74 subregions (mean 12 ± 3.7). Of the 310 LN, 35 turned out to be LNM on histopathology. Separation of the samples from all subregions resulted in 318 single specimens: 182 PCa-negative LN samples with 275 LN, 35 single LNM samples, 3 non-nodal PCa tissue samples and 98 fibrofatty tissue samples. The median SULs of nonaffected LN (0.16) and affected LN (13.2) were significantly different (p

Contains fulltext : 190311.pdf (Publisher’s version ) (Closed access) Importance: Cerebral amyloid-beta aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials. Objective: To investigate whether amyloid-beta aggregation is associated with cognitive functioning in persons without dementia. Design, Setting, and Participants: This cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017. Main Outcomes and Measures: Global cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score

Alexander disease (AD) is a rare leukodystrophy first described in 1949 with infantile, juvenile, or adult-onset Alexander disease (AOAD).1 The pathophysiologic hallmark of AD is the presence of corkscrew-shaped intracytoplasmic eosinophilic inclusions in astrocytes (Rosenthal fibers) on histologic examination.2 A noninvasive diagnosis is possible since the discovery of the corresponding gene ( GFAP ) encoding the glial fibrillary acidic protein in 2001.3 An autosomal dominant transmission with 100% penetrance has been described, but many patients with AD have de novo mutations not found in either parent.3-6 Disease progression, clinical phenotype, and imaging findings in AD differ enormously according to the age at onset (AAO). The phenotype in the poor prognostic infantile AD (AAO

Purpose Multiparametric magnetic resonance imaging (mpMRI) is widely used in radiation treatment planning of primary prostate cancer (PCA). Focal dose escalation to the dominant intraprostatic lesions (DIPL) may lead to improved PCA control. Prostate-specific membrane antigen (PSMA) is overexpressed in most PCAs. 68Ga-labelled PSMA inhibitors have demonstrated promising results in detection of PCA with PET/CT. The aim of this study was to compare 68Ga-PSMA PET/CT with MRI for gross tumour volume (GTV) definition in primary PCA.

The CD30-specific antibody–drug conjugate, brentuximab vedotin, is approved for the treatment of relapsed, refractory Hodgkin lymphomas and systemic anaplastic large T-cell lymphomas. Multiple ongoing clinical trials are investigating brentuximab vedotin efficacy in other CD30-positive hematologic malignancies. Because CD30 expression varies among different types of lymphoma and can also change during the course of treatment, companion diagnostic imaging of CD30 could be a valuable tool in optimizing patient-specific brentuximab vedotin treatment regimens. Methods: The mouse antihuman CD30 antibody AC-10 was radiolabeled with the positron-emitting radionuclide 89Zr. The stability and specificity of 89Zr-desferrioxamine (DFO)-labeled CD30-specific AC-10 antibody (89Zr-DFO-AC-10) was evaluated in vitro. The pharmacokinetics of 89Zr-DFO-AC-10 was studied in BALB/c nude mice bearing subcutaneous human Karpas 299 tumors (CD30-positive model) or A-431 tumors (CD30-negative model) using PET/CT imaging, biodistribution studies, and autoradiography. Results: AC-10 was conjugated with a DFO B chelator and radiolabeled with 89Zr to give formulated 89Zr-DFO-AC-10 with a radiochemical yield of 80%, radiochemical purity greater than 99%, and specific activity of 111–148 MBq/mg. 89Zr-DFO-AC-10 was stable in mouse and human sera and preserved the immunoreactivity toward CD30. Biodistribution data showed the highest tissue accumulation of 89Zr-DFO-AC-10 in CD30-positive tumors, with 37.9% ± 8.2% injected activity per gram of tissue at 72 h after injection, whereas uptake in CD30-negative tumors was 11.0% ± 0.4%. The specificity of 89Zr-DFO-AC-10 binding to CD30 in vivo was confirmed by blocking studies. Time–activity curves showed that between 24 and 144 h after injection, tumor-to-muscle ratios increased from 18.9 to 51.8 in the CD30-positive model and from 4.8 to 8.7 in the CD30-negative model. Tumor-to-blood ratios also increased, from 3.2 to 13.6 and from 1 to 2 in the CD30-positive and -negative models, respectively. Conclusion: Our results demonstrate that for measuring CD30 expression, 89Zr-DFO-AC-10 is a sensitive PET agent with high tumor–to–normal-tissue contrast. 89Zr-DFO-AC-10 is a promising CD30-imaging radiotracer for clinical translation in patients with various lymphomas and other diseases.

The gastrin-releasing peptide receptor (GRPr) is an important molecular target for the visualization and therapy of tumors and can be targeted with radiolabeled bombesin derivatives. The present study aims to develop statine-based bombesin receptor antagonists suitable for labeling with 64Cu for imaging by positron emission tomography (PET). The potent GRPr antagonist D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 was conjugated to the sarcophagine (3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane=Sar) derivative 5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.6]icosan-1-ylamino)-5-oxopentanoic acid (MeCOSar) via PEG4 (LE1) and PEG2 (LE2) spacers and radiolabeled with 64Cu2+ with >95% yield and specific activities of about 100 MBq/nmol. Both Cu(II) conjugates have high affinity for GRPr (IC50: natCu-LE1, 1.4±0.1 nM; natCu-LE2, 3.8±0.6 nM). The antagonistic properties of both conjugates were confirmed by Ca2+-flux measurements. Biodistribution studies of Cu-64-LE1 exhibited specific targeting of the tumor (19.6±4.7% IA/g at 1 h p.i.) and GRPr-positive organs. Biodistribution and PET images at 4 and 24 h postinjection showed increasing tumor-to-background ratios with time. This was illustrated by the acquisition of PET images showing high tumor-to-normal tissue contrast. This study demonstrates the high affinity of the MeCOSar-PEGx-bombesin conjugates to GRPr. The stability of 64Cu complexes of MeCOSar, the long half-life of 64Cu, and the suitable biodistribution profile of the 64Cu-labeled peptides lead to PET images of high contrast suitable for potential translation into the clinic.

Objectives Aim of this study was to quantify the binding of [123I]FP-CIT in striatum of healthy tree shrews. [123I]FP-CIT is widely used in clinical SPECT imaging to reveal nigrostriatal degeneration in aid of the diagnosis of clinically uncertain parkinsonian syndromes. Despite its wide clinical use, the saturation binding parameters of [123I]FP-CIT for the dopamine transporter (DAT) have not yet been determined in any mammalian brain. Tree shrews are genetically and neuroanatomically more similar to humans than are rodents and might therefore be a valuable animal model for research of neurological disorders involving brain dopamine. Experimental Design Quantitative in vitro autoradiography with [123I]FP-CIT was performed with brains of healthy tree shrews and, for comparison, brains of healthy rats. Dopamine D2/3 receptor autoradiography with [3H]raclopride was also performed. Principal observations Saturation analysis revealed high specificity of [123I]FP-CIT for DAT in the striatum with considerably higher affinity in tree shrews than in rats (KD = 10.3 versus 36.4 nM). The density of DAT binding sites also was higher in tree shrews than in rats (Bmax = 2499 versus 1495 pmol/g wet weight (ww)). [3H]raclopride revealed D2/3 receptors in the tree shrew striatum with about the same density as in rats (Bmax = 78.4 versus 84.1 pmol/g ww), but with slightly lower affinity in tree shrews (KD = 1.27 versus 0.59 nM). Conclusions The higher affinity in combination with the higher abundance of DAT binding sites compared to rat striatum predicts substantially higher binding of [123I]FP-CIT in SPECT studies of living tree shrews.

SPECT mit dem Kokain-Analogon [123I]FP-CIT wird fur den Nachweis oder Ausschluss der Degeneration nigrostriataler Neurone bei Patienten mit klinisch unklarem Parkinson-Syndrom eingesetzt. Die Beurteilung der Untersuchung basiert auf der visuellen Interpretation der SPECT-Bilder, die durch semiquantitative Analysen unterstutzt werden kann. Wesentlicher Nachteil der visuellen Bildbeurteilung gegenuber der semiquantitativen Analyse ist, dass sie prinzipiell subjektiv und insbesondere von der Erfahrung des Befunders abhangig ist. Im vorliegenden Artikel sind daher einfach anzuwendende Empfehlungen zusammengestellt, die den Arzt in der taglichen Routine bei der visuellen Differenzierung zwischen normaler und reduzierter striataler [123I]FP-CIT-Aufnahme im Sinne nigrostriataler Degeneration unterstutzen sollen. Anwendung der Empfehlungen sollte die Befunder-Abhangigkeit der visuellen Bildinterpretation bei der [123I]FP-CIT-SPECT reduzieren.

IMPORTANCE: Amyloid-β positron emission tomography (PET) imaging allows in vivo detection of fibrillar plaques, a core neuropathological feature of Alzheimer disease (AD). Its diagnostic utility is still unclear because amyloid plaques also occur in patients with non-AD dementia. OBJECTIVE: To use individual participant data meta-analysis to estimate the prevalence of amyloid positivity on PET in a wide variety of dementia syndromes. DATA SOURCES: The MEDLINE and Web of Science databases were searched from January 2004 to April 2015 for amyloid PET studies. STUDY SELECTION: Case reports and studies on neurological or psychiatric diseases other than dementia were excluded. Corresponding authors of eligible cohorts were invited to provide individual participant data. DATA EXTRACTION AND SYNTHESIS: Data were provided for 1359 participants with clinically diagnosed AD and 538 participants with non-AD dementia. The reference groups were 1849 healthy control participants (based on amyloid PET) and an independent sample of 1369 AD participants (based on autopsy). MAIN OUTCOMES AND MEASURES: Estimated prevalence of positive amyloid PET scans according to diagnosis, age, and apolipoprotein E (APOE) ε4 status, using the generalized estimating equations method. RESULTS: The likelihood of amyloid positivity was associated with age and APOE ε4 status. In AD dementia, the prevalence of amyloid positivity decreased from age 50 to 90 years in APOE ε4 noncarriers (86% [95% CI, 73%-94%] at 50 years to 68% [95% CI, 57%-77%] at 90 years; n = 377) and to a lesser degree in APOE ε4 carriers (97% [95% CI, 92%-99%] at 50 years to 90% [95% CI, 83%-94%] at 90 years; n = 593; P

BackgroundHashimoto’s encephalopathy (HE) is a rare immunological neuropsychiatric disorder characterized by increased antithyroid antibodies and mixed neurological and psychiatric symptoms. HE has been previously discussed as a differential diagnosis for rapid progressive dementia. However, most of these patients suffered from additional neurological symptoms, like ataxia or seizures.Case presentationHere, we present the case of a 59-year-old female patient suffering rapid onset dementia with salient frontal executive dysfunction. She developed rapid onset symptoms, including apathy, verbal depletion up to a stuporous state, severe working memory deficits, evidence of primitive reflexes, disturbed Luria’s three-step test, and micturition disorder. Analysis of her cerebrospinal fluid was normal. The serum analyses showed increased antithyroid (antithyroid peroxidase and antithyroglobulin) antibodies. In the cerebral magnetic resonance imaging, supratentorial deep and peripheral white matter lesions were found; the electroencephalography showed intermittent slowing, and the [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) depicted medial and superior dorsolateral frontal hypometabolism. Several different psychopharmacological therapeutic approaches with various neuroleptics, antidepressants, and high doses of lorazepam were unsuccessful. Due to the organic alterations, including increased antithyroid antibodies, HE was suspected. Against expectations, treatment with high-dose corticosteroids proved to be ineffective and was associated with worsening symptoms. However, escalated treatment with plasmapheresis over 5 days led to significant improvement in all reported symptoms and in psychometric testing. The neuropsychological improvement was stable over a 6-month follow-up period, and the FDG-PET normalized.ConclusionThis case report reveals that (1) HE can mimic rapid onset dementia with predominantly frontal dysfunction; (2) this syndrome can be successfully treated in the context of HE; and (3) plasmapheresis can be effective in such a disease constellation. The detection of the immunological causes of rapid onset dementia and other psychiatric syndromes is important because it opens opportunities for new, innovative immunosuppressive treatment options.

[In this retrospective study 16 men with biochemical PCa relapse and negative (n = 14) or inconclusive (n = 2)Even in this highly selected population of patients with known biochemical recurrence but negative or inconclusive

Background Despite an increasing number of O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) PET studies in supratentorial gliomas, studies regarding the usefulness of 18F-FET PET in brainstem and spinal cord gliomas to date remain scarce. Methods Thirty-six 18F-FET PET scans were performed in 29 patients with brainstem (n = 29 scans) or spinal cord glioma (n = 7 scans). In 32 of 36 PET scans, a dynamic acquisition was performed. Fifteen scans in 15 patients were performed to assess newly diagnosed lesions, and 21 scans were obtained during follow-up: for diagnosing tumor progression (n = 15 scans in 14 patients) as well as for treatment monitoring (n = 6 scans in 3 patients). Four patients underwent additional serial scans (range, 1-2), and 3 of these 4 patients were examined for more than one indication. Maximum and mean tumor/brain ratios (TBRmax/mean) of 18F-FET uptake (20-40 min post injection) as well as kinetic 18F-FET uptake parameters were determined. Final diagnoses were confirmed histologically (54%) or by clinical follow-up (46%). Results In all newly diagnosed high-grade (n = 3 patients) and in 5 of 11 patients with low-grade gliomas, 18F-FET uptake was increased (TBRmax ≥2.5 and/or TBRmean ≥1.9). In 2 patients with newly diagnosed gliomas without MR contrast enhancement, 18F-FET PET nevertheless showed increased metabolism. At suspected progression, the combination of TBRs with kinetic 18F-FET parameters correctly identified presence or absence of progressive disease in 9 of 11 patients (82%). Conclusions This preliminary study suggests that 18F-FET PET adds valuable diagnostic information in brainstem and spinal cord glioma, particularly when the diagnostic information derived from MRI is equivocal.

Patients with BRAFV600E/K-driven melanoma respond to the BRAF inhibitor vemurafenib due to subsequent deactivation of the proliferative RAS/RAF/MEK/ERK pathway. In BRAF WT cells and those with mutations that activate or result in high levels of the BRAF activator RAS, BRAF inhibition can lead to ERK activation, resulting in tumorigenic transformation. We describe a patient with malignant melanoma who developed chronic lymphocytic leukemia (CLL) in the absence of RAS mutations during vemurafenib treatment. BRAF inhibition promoted patient CLL proliferation in culture and in murine xenografts and activated MEK/ERK in primary CLL cells from additional patients. BRAF inhibitor-driven ERK activity and CLL proliferation required B cell antigen receptor (BCR) activation, as inhibition of the BCR-proximal spleen tyrosine kinase (SYK) reversed ERK hyperactivation and proliferation of CLL cells from multiple patients, while inhibition of the BCR-distal Bruton tyrosine kinase had no effect. Additionally, the RAS-GTP/RAS ratio in primary CLL cells exposed to vemurafenib was reduced upon SYK inhibition. BRAF inhibition increased mortality and CLL expansion in mice harboring CLL xenografts; however, SYK or MEK inhibition prevented CLL proliferation and increased animal survival. Together, these results suggest that BRAF inhibitors promote B cell malignancies in the absence of obvious mutations in RAS or other receptor tyrosine kinases and provide a rationale for combined BRAF/MEK or BRAF/SYK inhibition.

Ziel der Studie: Die Messung des regionalen zerebralen Glukosemetabolismus mittels der [18F]Fluorodeoxyglukose-Positronen-Emissions-­Tomografie (FDG-PET) sowie die Beurteilung struktureller Auffalligkeiten des Hirnstammes und der Basalganglien mittels transkranieller ­B-mode ­Sonografie (TCS) konnen zur bildgebenden ­Differenzialdiagnostik des Parkinson-Syndromes eingesetzt werden. Wir untersuchten die diagnostische Wertigkeit beider Verfahren zur Fruhdiagnose und Differenzierung atypischer Parkinson-Syndrome (APS). Methodik: Die Daten von 36 Patienten, welche sich mit der klinischen Verdachtsdiagnose eines APS zur kombinierten Bildgebung mittels PET und TCS vorstellten, wurden analysiert. Die ­FDG-PET wurde basierend auf a priori definierten Befundmustern visuell befundet (Schnittbilder der FDG-Aufnahme sowie voxel-basierte statistische Auswertung mittels Neurostat/3D-SSP). Die sonografische Diagnose wurde anhand vorab definierter Parameter (Echogenitat von Substantia nigra und Linsenkern; Durchmesser III. Ventrikel) vergeben. Zunachst wurden Patienten mit einem APS-typischen Befundmuster identifiziert und nachfolgend den APS-Subgruppen Multisys­tematrophie (MSA), progressive supranukleare Blickparese (PSP) oder kortikobasale Degenera­tion (CBD) zugeordnet. Ergebnisse: Nach einer mittleren Follow-up Dauer von 9 Monaten wurden folgende finale klinische Diagnosen (Referenzstandard) gestellt: Morbus Parkinson (n=15), MSA (n=9), PSP (n=7) und CBD (n=5) (n=21 APS gesamt). Bei 6 Patienten (4 APS) war die TCS aufgrund eines insuffizienten Schallfensters nicht durchfuhrbar. Insgesamt wurden 30 Patienten in der statistischen Auswertung berucksichtigt. Die Sensitivitat und Spezifitat der FDG-PET fur die Diagnose des APS betrug 82% bzw. 100% und der TCS 82% bzw. 85%. Die diagnostische Genauigkeit der ­FDG-PET (90%) und der TCS (83%; p=0,69) fur die Diagnose des APS unterschied sich nicht. Zudem fand sich kein Unterschied beim Vergleich der diagnostischen Genauigkeit der Subgruppenklassifikation (non-APS, MSA, PSP, CBD) zwischen beiden Untersuchungsverfahren (FDG-PET 87%; TCS 83%, p=1,00). Schlussfolgerung: Die diagnostische Genauigkeit der FDG-PET und der TCS ist vergleichbar bei der Differenzialdiagnose des Parkinson-Syndroms. Die Ergebnisse der vorliegenden Studie unterstreichen den Einsatz der TCS und erfordern eine prospektive Validierung.

Objective To determine the functional correlates of vertical gaze palsy and other ocular motor deficits in patients with progressive supranuclear palsy (PSP) using [ 18 F]fluorodeoxyglucose (FDG-)PET. Methods Twenty-six patients with PSP underwent clinical examination of vertical gaze combined with FDG-PET scans to assess regional cerebral glucose metabolism as a marker of neuronal activity. Of these, eighteen PSP patients were also investigated by electrical nystagmography to determine horizontal ocular motor deficits. Statistical parametric mapping analyses were performed to correlate regional neuronal activity with ocular motor functions. Results In categorical comparisons, patients with downward gaze palsy showed a significantly reduced glucose metabolism in bilateral anterior cingulate gyrus and right lingual gyrus compared to those without downward gaze palsy. Maximum velocity of horizontal saccades was positively correlated with glucose metabolism of the rostral vermis and lingual gyrus; regional metabolism of oculomotor vermis was associated with peak velocity of the optokinetic reflex. Analysis of smooth pursuit eye movement amplitude and peak velocity of corrective saccades showed positive correlation with metabolism in bilateral inferior parietal lobe and inferior part of the frontal eye field. All paradigms of smooth pursuit showed positive association with glucose metabolism in V5. Conclusions Ocular motor functions in PSP are correlated with neuronal activity in distinct anatomical regions. These include the anterior cingulate gyrus (downward gaze palsy), rostral cerebellum (saccades), oculomotor vermis (optokinetic reflex) and inferior parietal as well as temporal regions and frontal eye field (smooth pursuit). These findings provide a deeper insight into the pathophysiology of PSP-associated ocular motor abnormalities.

To give an update on recent findings concerning the use of single-photon emission computed tomography (SPECT) and positron emission tomography (PET) for differential diagnosis and prognosis of neurodegenerative parkinsonism and related disorders.Several studies confirmed the very high diagnostic accuracy and clinical impact of imaging nigrostriatal function (most notably with [I]FP-CIT-SPECT) for diagnosing neurodegenerative parkinsonism and dementia with Lewy bodies. Accurate differential diagnosis of neurodegenerative parkinsonism can be achieved by imaging disease-specific patterns of cerebral glucose metabolism with [18F]fluorodeoxyglucose-PET, which surpasses the diagnostic accuracy of other currently available radionuclide imaging techniques.SPECT and PET are established methods for the differential diagnosis of parkinsonism with significant therapeutic and prognostic impact. Given the limited accuracy of the clinical diagnosis as the reference standard, future studies with post-mortem verification are needed for validation of diagnostic imaging pattern, particularly in tauopathies.

Purpose 18F-Fluoroethylcholine (18F-FECh) is excreted via the urinary system with high activity accumulation in the urinary bladder. Furosemide and oral hydration can be administered concomitantly to reduce urinary activity to provide better detectability of retroperitoneal and pelvic lesions. Currently it is unknown if there is any effect of furosemide on 18F-FECh uptake in organs, tissues and tumour lesions and the extent to which image quality along the urinary tract may be improved by furosemide.

Treatment of recurrent glioblastoma (rGBM) remains an unsolved clinical problem. Reirradiation (re-RT) can be used to treat some patients with rGBM, but as a monotherapy it has only limited efficacy. Chloroquine (CQ) is an anti-malaria and immunomodulatory drug that may inhibit autophagy and increase the radiosensitivity of GBM. Between January 2012 and August 2013, we treated five patients with histologically confirmed rGBM with re-RT and 250 mg CQ daily. Treatment was very well tolerated; no CQ-related toxicity was observed. At the first follow-up 2 months after finishing re-RT, two patients achieved partial response (PR), one patient stable disease (SD), and one patient progressive disease (PD). One patient with reirradiated surgical cavity did not show any sign of PD. In this case series, we observed encouraging responses to CQ and re-RT. We plan to conduct a CQ dose escalation study combined with re-RT.

We present a patient with chronic postmenopausal estrogen intake with presence of Kayser-Fleischer ring in the cornea and Alzheimer's disease and discuss the pathophysiological mechanisms of estrogen intake and copper accumulation in various tissues, including the central nervous system. Sonography was compatible with copper accumulation in the basal ganglia, but the patient showed no clinical signs of Wilson's disease. Magnetic resonance imaging and positron emission tomography revealed a typical pattern for Alzheimer's disease. We propose increased copper levels as a direct effect of estrogen intake due to an augmented ATP7A-mRNA in the intestine. Moreover, we discuss the impact of elevated free serum copper on accompanying Alzheimer's disease, knowing that copper plays a crucial role in the formation of amyloid plaques and tau aggregation. This might offer a partial explanation for the observation that postmenopausal estrogen therapy is associated with a higher risk of mild cognitive impairment and Alzheimer's disease.

Progressive supranuclear palsy (PSP) is characterized by a symmetric hypokinetic syndrome with early falls and vertical supranuclear gaze palsy. However, clinically asymmetric manifestations occur, resembling idiopathic Parkinson disease or corticobasal degeneration. The aim of this study was to determine the neuronal correlates of patients suffering from PSP with a lateralized disease manifestation (hemi-PSP) in comparison to patients with symmetric clinical presentation (symPSP) and corticobasal degeneration.Twenty-three patients with PSP and 8 patients with corticobasal degeneration according to standard diagnostic criteria underwent F-fluorodeoxyglucose (FDG) PET scans to assess disease-specific patterns of regional cerebral glucose metabolism reflecting neuronal activity. Group differences were analyzed by statistical parametric mapping and region-of-interest analyses.Clinically, 14 patients presented with symPSP while 9 patients were considered as hemi-PSP. Patients with symPSP or hemi-PSP showed similar bilateral medial frontal hypometabolism compared to corticobasal degeneration patients. In contrast, corticobasal degeneration patients exhibited a prominent parietal hypometabolism compared to both symPSP and hemi-PSP patients. SymPSP patients showed no significant hypometabolism compared to hemi-PSP, whereas hemi-PSP patients presented with significant hypometabolism of the motor thalamus, middle cingulate gyrus, and sensorimotor cortex contralateral to the most affected body side compared to symPSP patients.The present study demonstrates that a more pronounced and asymmetric involvement of cortical and subcortical motor areas is associated with a lateralized disease manifestation of PSP. Furthermore, these findings strongly suggest that FDG PET imaging may assist the challenging clinical differentiation between hemi-PSP and corticobasal degeneration by depicting disease-specific patterns of regional cerebral glucose metabolism.

BACKGROUND Posterior cortical atrophy (PCA) is a rare neurodegenerative syndrome with visuospatial deficits. PET studies have identified hypometabolism of the occipital cortex in PCA. There is, however, a huge overlap in clinical presentation and involvement of the occipital cortex between PCA, dementia with Lewy bodies (DLB), and Alzheimer's disease (AD). Syndrome-specific patterns of metabolism have not yet been demonstrated that allow for a reliable differentiation with [F-18]-FDG-PET. METHODS A total of 33 dementia patients (PCA n = 6, DLB n = 12, AD n = 15) who underwent [F-18]-FDG-PET imaging and a neuropsychological examination were retrospectively analyzed. Group comparisons of regional cerebral glucose metabolism were calculated with statistical parametric mapping. Extracted clusters were used to evaluate discrimination accuracy by logistic regression. RESULTS PCA patients showed a syndrome-specific area of hypometabolism in the right lateral temporooccipital cortex. DLB patients showed specific hypometabolism predominantly in the left occipital cortex. Logistic regression based on these two regions correctly separated patients with a sensitivity/specificity of 83/93% for PCA, 75/86% for DLB and 67/78% for AD. Overall accuracy was 73%. CONCLUSION [F-18]-FDG-PET could reveal syndrome-specific patterns of glucose metabolism in PCA and DLB. Accurate group discrimination in the differential diagnosis of dementia with visuospatial impairment is feasible.

Irradiation of salivary glands remains the main dose-limiting side effect of therapeutic PSMA-inhibitors, especially when using alpha emitters. Thus, further advances in radiopharmaceutical design and therapy strategies are needed to reduce salivary gland uptake, thereby allowing the administration of higher doses and potentially resulting in improved response rates and better tumor control. As the uptake mechanism remains unknown, this work investigates the salivary gland uptake of [177Lu]Lu-PSMA-617 by autoradiography studies on pig salivary gland tissue and on PSMA-overexpressing LNCaP cell membrane pellets. Displacement studies were performed with non-labeled PSMA-617 and 2-PMPA, respectively. The uptake of [177Lu]Lu-PSMA-617 in glandular areas was determined to be partly PSMA-specific, with a high non-specific uptake fraction. The study emphasizes that [177Lu]Lu-PSMA-617 accumulation in pig salivary glands can be attributed to a combination of both specific and non-specific uptake mechanisms. The observation is of high impact for future design of novel radiopharmaceuticals addressing the dose-limiting salivary gland irradiation of current alpha endoradiotherapy in prostate cancer.

We investigated disease-specific cognitive profiles and their neural correlates in Lewy-body diseases (LBD) and tauopathies by CERAD assessment and FDG-PET. Analyses revealed a significant interaction between reduced semantic fluency in tauopathies and impaired verbal learning in LBD. Semantic fluency discriminated between groups with high accuracy (83%). Compared to LBD, tauopathy patients showed bilateral hypometabolism of midbrain, thalamus, middle cingulate gyrus and supplementary motor/premotor cortex. In the reverse contrast, LBD patients exhibited bilateral hypometabolism in posterior parietal cortex, precuneus and inferior temporal gyrus extending into occipital and frontal cortices. In diagnosis-independent voxel-based analyses, verbal learning/memory correlated with left temporal and right parietal metabolism, while fluency was coupled to bilateral striatal and frontal metabolism. Naming correlated with left frontal metabolism and drawing with metabolism in bilateral temporal and left frontal regions. In line with disease-specific patterns of regional glucose metabolism, tauopathies and LBD show distinct cognitive profiles, which may assist clinical differentiation.

Amyloid-b (Ab) deposition is a pathologic hallmark of Alzheimer disease (AD). Although the typical spatial distribution pattern of Ab deposition in early AD mainly involves regions distant from the hippocampus, the predominant clinical feature is impairment of hippocampusdependent memory. We aimed at elucidating the relationship between neocortical Ab load, regional neuronal function, and memory impairment. Methods: Thirty patients with early AD underwent combined 11 C-Pittsburgh compound B ( 11 C-PIB) and 18 F-FDG PET and memory assessments. Composite measures of hemispheric Ab load were calculated by volume-weighted mean values of neocortical 11 C-PIB binding. Voxelwise 18 F-FDG uptake was used as a measure of regional glucose metabolism reflecting neuronal activity. We investigated the relationship between left- and right-hemispheric Ab load and regional glucose metabolism (voxelwise analyses). In addition, we assessed the correlations of hemispheric Ab load (region-ofinterest–based analyses) and regional glucose metabolism (voxelwise analysis) with memory performance. Analyses were corrected for age and sex. Results: Higher Ab load in the left hemisphere was associated with reduced glucose metabolism of the left medial temporal lobe (MTL; r 2 5 0.38) and correlated with worse wordlist recall (r 52 0.37; partial correlation controlled for sex and age). Furthermore, wordlist recall correlated with regional glucose metabolism in the bilateral MTL and precuneus–posterior cingulate cortex and right lingual gyrus (r2 5 0.24). Conclusion: We demonstrated an association between the left-hemispheric Ab load and impairment of the left MTL in AD at 2 different levels: regional hypometabolism and verbal memory. This correlation suggests that neocortical amyloid deposition is connected to or even drives neuronal dysfunction and neurodegeneration of the MTL, which is associated with impaired episodic memory processing as a clinical core symptom of AD.

In Huntington's disease (HD) cognitive deficits co-exist with motor impairments, both contributing to the overall disease symptomology. Despite short-term and working memory impairments, learning and other non-motoric behavioral deficits arising from the damage to frontostriatal loop being common in HD patients, most of the experimental work with transgenic animals focuses on motor symptoms. The transgenic rat model (tgHD) recapitulates many hallmark HD-like symptoms, such as huntingtin aggregates, cellular loss and dysfunction, and motor, and some cognitive deficits. In the current study we tested tgHD rats in two different cognitive, water maze competition paradigms to learn more about the impact of the transgene on learning and memory processing using hippocampal- and striatal-based memory systems. The tgHD rats had early and robust cognitive deficits in learning and memory function in both paradigms. Specifically, the transgenic animals were impaired in task acquisition and committed more procedural errors with the strongest phenotype amongst the homozygote tgHD. Although the transgenic animals were capable of using both procedural and declarative memory, their response patterns were distinct from wild-type animals. Wide spread huntingtin aggregates were observed at 13 months, but neither PET nor autoradiography indicated neuronal loss or dysfunction in striatal dopamine receptor population. In summary, the homozygote tgHD showed a robust learning and memory impairment prior to any clear motor deficits, or striatal dysfunction. However, the data were not conclusive regarding how the memory systems were compromised and the precise nature and underlying mechanism of the cognitive deficit in the tgHD model requires further investigation.

The higher specificity of amino-acid positron emission tomography (AA-PET) in the diagnosis of gliomas, as well as in the differentiation between recurrence and treatment-related alterations, in comparison to contrast enhancement in T1-weighted MRI was demonstrated in many studies and is the rationale for their implementation into radiation oncology treatment planning. Several clinical trials have demonstrated the significant differences between AA-PET and standard MRI concerning the definition of the gross tumor volume (GTV). A small single-center non-randomized prospective study in patients with recurrent high grade gliomas treated with stereotactic fractionated radiotherapy (SFRT) showed a significant improvement in survival when AA-PET was integrated in target volume delineation, in comparison to patients treated based on CT/MRI alone. This protocol describes a prospective, open label, randomized, multi-center phase II trial designed to test if radiotherapy target volume delineation based on FET-PET leads to improvement in progression free survival (PFS) in patients with recurrent glioblastoma (GBM) treated with re-irradiation, compared to target volume delineation based on T1Gd-MRI. The target sample size is 200 randomized patients with a 1:1 allocation ratio to both arms. The primary endpoint (PFS) is determined by serial MRI scans, supplemented by AA-PET-scans and/or biopsy/surgery if suspicious of progression. Secondary endpoints include overall survival (OS), locally controlled survival (time to local progression or death), volumetric assessment of GTV delineated by either method, topography of progression in relation to MRI- or PET-derived target volumes, rate of long term survivors (>1 year), localization of necrosis after re-irradiation, quality of life (QoL) assessed by the EORTC QLQ-C15 PAL questionnaire, evaluation of safety of FET-application in AA-PET imaging and toxicity of re-irradiation. This is a protocol of a randomized phase II trial designed to test a new strategy of radiotherapy target volume delineation for improving the outcome of patients with recurrent GBM. Moreover, the trial will help to develop a standardized methodology for the integration of AA-PET and other imaging biomarkers in radiation treatment planning. The GLIAA trial is registered with ClinicalTrials.gov ( NCT01252459 , registration date 02.12.2010), German Clinical Trials Registry ( DRKS00000634 , registration date 10.10.2014), and European Clinical Trials Database (EudraCT-No. 2012-001121-27, registration date 27.02.2012).

GLP-1 receptors are ideal targets for preoperative imaging of benign insulinoma and for quantifying the beta cell mass. The existing clinical tracers targeting GLP-1R are all agonists with low specific activity and very high kidney uptake. In order to solve those issues we evaluated GLP-1R agonist Ex-4 and antagonist Ex(9-39) radioiodinated at Tyr40 side by side with [Nle14,Lys40(Ahx-DOTA-68Ga)NH2]Ex-4 (68Ga-Ex-4) used in the clinic. The Kd, Bmax, internalization and binding kinetics of [Nle14,125I-Tyr40-NH2]Ex-4 and [Nle14,125I-Tyr40-NH2]Ex (9-39) were studied in vitro using Ins-1E cells. Biodistribution and imaging studies were performed in nude mice bearing Ins-1E xenografts. In vitro evaluation demonstrated high affinity binding of the [Nle14,125I-Tyr40-NH2]Ex-4 agonist to the Ins-1E cells with fast internalization kinetics reaching a plateau after 30 min. The antagonist [Nle14,125I-Tyr40-NH2]Ex(9-39) did not internalize and had a 4-fold higher Kd value compared to the agonist. In contrast to [Nle14,125I-Tyr40-NH2]Ex(9-39), which showed low and transient tumor uptake, [Nle14,125I-Tyr40-NH2]Ex-4 demonstrated excellent in vivo binding properties with tumor uptake identical to that of 68Ga-Ex-4, but substantially lower kidney uptake resulting in a tumor-to-kidney ratio of 9.7 at 1 h compared to 0.3 with 68Ga-Ex-4. Accumulation of activity in thyroid and stomach for both peptides, which was effectively blocked by irenat, confirms that in vivodeiodination is the mechanism behind the low kidney retention of iodinated peptides. The 124I congener of [Nle14,125I-Tyr40-NH2]Ex-4 demonstrated a similar favourable biodistribution profile in the PET imaging studies in contrast to the typical biodistribution pattern of [Nle14,Lys40(Ahx-DOTA-68Ga)NH2]Ex-4. Our results demonstrate that iodinated Ex-4 is a very promising tracer for imaging of benign insulinomas. It solves the problem of high kidney uptake of the radiometal-labelled tracers by improving the tumor-to-kidney ratio measured for [Nle14,Lys40(Ahx-DOTA-68Ga)NH2]Ex-4 by 32 fold.

BACKGROUND: [(11)C]MDL100,907 is a promising positron emission tomography (PET) ligand for 5-HT(2A) receptor quantification in vivo. Studies suggest that [(11)C]MDL100,907 PET may be quantified by non-invasive reference tissue analyses using cerebellum as reference region. We systematically investigated the validity of such analyses. METHODS: Five healthy volunteers underwent [(11)C]MDL100,907 PET at baseline and after mirtazapine pre-treatment. Regional time-activity curves of 10 regions of interest (ROI) were analyzed for binding potential (BP(ND)) and mirtazapine receptor occupancy (Occ) using: simplified reference tissue model (SRTM), multi-linear reference tissue model (MRTM), their two-parameter versions (SRTM2/MRTM2), non-invasive graphical analysis (NIGA) and a tissue activity concentration ratio. NIGA was also applied voxel-wise to generate BP(ND) maps. These methods were compared with a two-tissue compartment model with arterial input function (2TCM) Results: SRTM and MRTM frequently failed to yield reliable results. SRTM2 and MRTM2 gave virtually identical estimates of BP(ND), which were highly correlated with 2TCM analyses (R(2)>or=0.86) although with negative bias (-29+/-27% at baseline across all ROI). NIGA was less biased (-19+/-16%) and better correlated with 2TCM (R(2)>or=0.93). Regarding Occ, NIGA and SRTM2/MRTM2 showed comparable mean biases (-11+/-27% vs. -7+/-47%) but correlation with 2TCM was higher for NIGA (R(2)=0.90 vs. 0.77). NIGA parametric maps (analysed using identical ROI) resulted in moderate bias in BP(ND) (-26+/-22%; R(2)>or=0.88) and Occ (-17+/-36%; R(2)=0.78). Estimates obtained from tissue ratios performed least favourably. CONCLUSIONS: NIGA is well suited for analysis of [(11)C]MDL100,907 PET studies, yielding estimates of 5-HT(2A) receptor availability and changes that are highly correlated with results from invasive 2TCM analyses. This should greatly enhance the applicability of 5-HT(2A) receptor PET studies.

Summary The clinical appearance of patients with hypothalamic hamartomas is very heterogeneous, and interindividual variability of intellectual abilities is not completely understood. We retrospectively investigated cerebral dysfunction as indicated by reduced regional glucose metabolism in 29 patients (age range 7–49 years) with epilepsy due to hypothalamic hamartomas. Brain metabolism assessed by [18F]FDG-PET was compared between patients with and without cognitive impairment controlled for unevenly distributed hamartoma lateralization seen on magnetic resonance imaging (MRI). Due to the broad age range, the variable “age” was included in the imaging analyses as a covariate. Additional voxel-wise analysis with hamartoma volume, disease duration, seizure severity, seizure frequency, and antiepileptic drug (AED) load as well as dosage and gender as further covariates was accomplished. Furthermore, global visual ratings on laterality of hypometabolism patterns were assessed according to clinical standards and related to hamartoma lateralization on MRI as well as lateralization of electroencephalography (EEG) abnormalities. Cognitively impaired patients showed significantly reduced glucose metabolism in bilateral frontal as well as right parietal and posterior midline cortices (p

O-(2-F-18-fluoroethyl)-L-tyrosine (F-18-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect F-18-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by F-18-FET PET and to elucidate the pathophysiologic background. Methods: Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and F-18-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II-1V (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/ LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3). Results: All patients exhibited increased seizure-associated strict gyral F-18-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. F-18-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread 1 lobe) cortical F-18-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis. Conclusion: Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral F-18-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of F-18-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression.

Recently, a number of positron emission tomography (PET) radiotracers have been approved for clinical use. These tracers target cerebral beta-amyloid (Aβ) plaques, a hallmark of Alzheimer's disease. Increasing use of this method implies the need for respective standards. This German Society of Nuclear Medicine guideline describes adequate procedures for Aβ plaque PET imaging. It not only discusses the tracers used for that purpose, but also lists measures for correct patient preparation, image data generation, processing, analysis and interpretation. With that, this "S1" category (according to the German Association of the Scientific Medical Societies standard) guideline aims at contributing to quality assurance of nuclear imaging in Germany.

INTRODUCTION AND OBJECTIVES: Accurate imaging of lymph node metastases (LNM) is a prerequisite for metastases directed therapies such as salvage lymph node dissection (salvage-LND) in nodal recurrent prostate cancer (PCa). Our aim was to evaluate the diagnostic accuracy of 68PSMA-PET/CT (DKFZ-11) for nodal relapse of PCa according to different topographical locations and the size of tumor deposits in lymph nodes (LN). METHODS: 25 patients with the suspicion of nodal PCa-relapse after primary therapy underwent pelvic and/or retroperitoneal salvage-LND after a whole body PET/CT with 68Ga-PSMA showing PET-positive lesions. Time from PET/CT to salvage-LND was median 2.3 months. Diagnostic accuracy of PET/CT for dissected main-regions (pelvic left/right, retroperitoneal) and subregions (common, external, internal iliac, obturatoria, presacral, aortic-bifurcation, aortal, caval, interaortocaval) was determined by comparing histopathologic results with PET/CT-findings. Size ofmetastatic infiltration inLNwasmeasuredbasedonhistopathology. RESULTS: Mean PSA at salvage-LND was 3.03 ng/ml (SD 3.2 / median 1.74 ng/ml). Overall, 833 LN were resected in 25 patients, containing 98 LNM, corresponding to a mean of 33.3 LN and 3.9 LNM per patient. In 5 patients (8 subregions) tissue containing solid non-nodal local relapse was additionally resected. LN were removed in portions out of 10 subregions per patient leading to 251 subregions available for evaluation. Median 3 LN were removed per subregion. For 2/25 patients and in 7/251 subregions, the suspected tumor involvement was verified by follow-up PET/CT showing progress of the lesions and PSA increase. 35/60 (58.3%) of the main regions and 63/251 (25%) of the subregions were PET-positive. Sensitivity, specifity, positive predictive value (PPV), negative predictive value (NPV) and accuracy based on a main-region analysis was 92.1% (35/38), 100% (22/22), 100% (35/35), 88.0% (22/25) and 95.0% (57/60). Based on a subregion-analyses sensitivity, specifity, PPV, NPV and accuracy was 80.7 % (63/78), 100% (173/173), 100% (63/63), 92.0% (173/188) and 94.0% (236/251). Median diameter (6 mm) of tumor deposits in LNM removed from true-positive subregions was significantly different to LNM resected from false-negative subregions (2 mm) (p