Cécile Colavolpe

Usefulness of 2‐[18F]‐fluoro‐2‐deoxy‐d‐glucose–Positron Emission Tomography/Computed Tomography for Staging and Evaluation of Treatment Response in IgG4‐Related Disease: A Retrospective Multicenter Study

To evaluate the usefulness of 2‐[18F]‐fluoro‐2‐deoxy‐d‐glucose–positron emission tomography/computed tomography (FDG‐PET/CT) in IgG4‐related disease (IgG4‐RD) for the staging of the disease and the followup under treatment.

Predictive value of brain perfusion SPECT for rTMS response in pharmacoresistant depression

PurposeThe aim of this study was to determine the predictive value of whole-brain voxel-based regional cerebral blood flow (rCBF) for repetitive transcranial magnetic stimulation (rTMS) response in patients with pharmacoresistant depression.MethodsThirty-three right-handed patients who met DSM-IV criteria for major depressive disorder (unipolar or bipolar depression) were included before rTMS. rTMS response was defined as at least 50% reduction in the baseline Beck Depression Inventory scores. The predictive value of 99mTc-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) for rTMS response was studied before treatment by comparing rTMS responders to non-responders at voxel level using Statistical Parametric Mapping (SPM) (p < 0.001, uncorrected).ResultsOf the patients, 18 (54.5%) were responders to rTMS and 15 were non-responders (45.5%). There were no statistically significant differences in demographic and clinical characteristics (p > 0.10). In comparison to responders, non-responders showed significant hypoperfusions (p < 0.001, uncorrected) in the left medial and bilateral superior frontal cortices (BA10), the left uncus/parahippocampal cortex (BA20/BA35) and the right thalamus. The area under the curve for the combination of SPECT clusters to predict rTMS response was 0.89 (p < 0.001). Sensitivity, specificity, positive predictive value and negative predictive value for the combination of clusters were: 94, 73, 81 and 92%, respectively.ConclusionThis study shows that, in pharmacoresistant depression, pretreatment rCBF of specific brain regions is a strong predictor for response to rTMS in patients with homogeneous demographic/clinical features.

FDG-PET predicts survival in recurrent high-grade gliomas treated with bevacizumab and irinotecan

Prognosis of recurrent high-grade glioma (HGG) is poor, although bevacizumab has been documented in that context. This study aimed to determine the independent prognostic value of fluorodeoxyglucose (FDG)-PET on progression-free survival (PFS) and overall survival (OS) of recurrent HGG after combined treatment with bevacizumab and irinotecan, compared with other documented prognostic variables. Twenty-five adult patients with histologically proven HGG were included at recurrence. Brain FDG-PET imaging was performed within 6 weeks of starting chemotherapy with bevacizumab and irinotecan. Response based on MRI was assessed every 2 months according to revised assessment in Neuro-Oncology (RANO) criteria. Median PFS and OS were 4 months (range, 0.9-10.4 months) and 7.2 months (range, 1.2-41.7 months), respectively. At 6 months, PFS and OS rate were 16.0% and 72.0%. FDG uptake was the most powerful predictor of both PFS and OS, using either univariate or multivariate analysis, among all variables tested: histological grade, Karnofsky performance status, steroid intake, and number of previous treatments. Moreover, FDG uptake was also prognostic of response to bevacizumab-based therapy. This study provides the first evidence that pretreatment FDG-PET can serve as an imaging biomarker in recurrent HGG for predicting survival following anti-angiogenic therapy with bevacizumab.

Utility of FDG-PET/CT in the follow-up of neuroblastoma which became MIBG-negative.

To the Editor:We readwith interest the article byColavolpe et al. [1] and wish to report a similar case with regard to negative MIBG scintigraphy in a relapsed neuroblastoma initially positive. A 15-month-old female presented with a right adrenal INSS stage 3 high-risk neuroblastoma (MYCN amplified, 1p deleted and with 17q unbalanced gain). Treatment was given following the European High-Risk Neuroblastoma protocol (NB 2002 06), with OPEC/ OJEC induction, total surgical excision, high-dose CEM, local radiotherapy, and 6 months of cis-retinoic acid orally. Fifteen months after treatment completion, a very small (3.2 cm 1.0 cm) para-aortic mass was seen on a routine CT scan, suggestive of local relapse. Urinary catecholamines and MIBG scintigraphy were both negative, having been positive at diagnosis. A CT scan repeated 3 months later revealed a definite relapse (5.4 cm 3.1 cm), but urinary catecholamines remained normal and MIBG scanning only showed negligible uptake. Multiple needle biopsies confirmed the relapse, showing completely undifferentiated neuroblastoma. As described in the patient reported by Colavolpe et al. [1], this patient appears unusual in that MIBG positivity was present at diagnosis, but uptakewas absent at relapse. The reliability ofMIBG scintigraphy in detecting relapse has been reported earlier [2–4], and a combination of investigations also including FDG PET/CT scanning has recently been advocated [5]. One reason for a lack or loss of MIBG avidity has been described as related to the interference in the uptake by concomitant medications, but not the reason in our patient. Lack of neuronal differentiation has been proposed as a further mechanism for change in avidity. Unlike the case described by Colavolpe et al. [1], our patient did show marked differences in histology between diagnosis and recurrence, the latter showing no differentiation. The prevalence of intra-patient alteration for MIBG avidity is difficult to establish from the published literature, but we suspect it is more common than previously thought. This alteration in behavior brings under question the panel of follow-up investigations most appropriate for detecting relapse, and we would agree with Colavolpe et al. [1] and Kushner et al. [5] that FDG PET/CT now has a role in routinely establishing disease status. Heather Mc Dowell, MD, FRCPCH* Department of Oncology Alder Hey Children’s NHS Foundation Trust Liverpool, UK

FDG-PET/CT is a pivotal imaging modality to diagnose rare intravascular large B-cell lymphoma: case report and review of literature

Intravascular large B‐cell lymphoma (IVLBCL) remains a diagnostic challenge, because of non‐specific findings on clinical, laboratory, and imaging studies. We present a case in which 18F‐fluorodeoxyglucose (FDG)‐positron emission tomography (PET)/computed tomography was particularly useful to suspect the diagnosis, to detect unexpected locations, to guide contributive biopsy, and to assess the response to treatment. In case of initial negative results, FDG‐PET should be repeated in the course of clinical evolution. In the presence of neurological or hormonal symptoms without brain magnetic resonance imaging abnormality, FDG‐PET brain slices could depict additional pituitary and/or brain hypermetabolisms. We discuss the potential interests of FDG‐PET in IVLBCL by a literature review. Copyright

Tomoscintigraphy improves the determination of the embryologic origin of parathyroid adenomas, especially in apparently inferior glands: imaging features and surgical implications.

Identification of the embryologic origin of hyperfunctioning parathyroid adenomas in primary hyperparathyroidism (PHPT) could determine the most suitable approach for minimally invasive surgery. The aim of this study was to prospectively evaluate the reliability of a new, combined protocol for the preoperative localization and determination of the embryologic origin of parathyroid adenomas. Methods: Anterior dual-isotope (123I/99mTc-sestamibi) static planar imaging followed by tomoscintigraphy (SPECT acquisition) centered over the 140-keV photopeak (combined protocol) was performed on 35 consecutive patients with sporadic PHPT. On the basis of anatomic considerations, adenomas were classified as superior (P4 derived) if they were located above the isthmus or posterior to the thyroid on SPECT images, despite their apparently middle to inferior position, and as inferior (P3 derived) if the foci were located in inferior and anterior positions or along the thyrothymic tract. Parathyroid ultrasonography was performed on all patients. Results: A total of 36 adenomas were removed: 34 solitary adenomas and 1 double adenoma (for totals of 19 P3-derived and 17 P4-derived adenomas). Pinhole subtraction imaging, SPECT, and ultrasonography sensitivities for detecting adenomas were 86%, 78%, and 77%, respectively. False-positive contralateral images were observed only with ultrasonography (3 cases). Positive SPECT results were associated with higher gland weights. Thirteen glands were identified by SPECT as posterior glands, despite their apparently inferior position, and were removed through an appropriate lateral endoscopic approach. Eleven (85%) of these glands had a P4 origin. Only 2 corresponded to large P3-derived adenomas (>2 g). Conclusion: By reclassifying apparently inferior adenomas as P4-derived adenomas prolapsed behind the thyroid gland, SPECT provides information about the most suitable surgical approach for avoiding recurrent laryngeal nerve injury. Additional pinhole images should increase the detection of small adenomas. The combined protocol offers both advantages.

Equivalent brain SPECT perfusion changes underlying therapeutic efficiency in pharmacoresistant depression using either high-frequency left or low-frequency right prefrontal rTMS

BACKGROUND Functional neuroimaging studies have suggested similar mechanisms underlying antidepressant effects of distinct therapeutics. OBJECTIVE This study aimed to determine and compare functional brain patterns underlying the antidepressant response of 2 distinct protocols of repetitive transcranial magnetic stimulation (rTMS). METHODS 99mTc-ECD SPECT was performed before and after rTMS of dorsolateral prefrontal cortex in 61 drug-resistant right-handed patients with major depression, using high frequency (10Hz) left-side stimulation in 33 patients, and low frequency (1Hz) right-side stimulation in 28 patients. Efficiency of rTMS response was defined as at least 50% reduction of the baseline Beck Depression Inventory score. We compared the whole-brain voxel-based brain SPECT changes in perfusion after rTMS, between responders and non-responders in the whole sample (p<0.005, uncorrected), and separately in the subgroup of patients with left- and right-stimulation. RESULTS Before rTMS, the left- and right-prefrontal stimulation groups did not differ from clinical data and brain SPECT perfusion. rTMS efficiency (evaluated on % of responders) was statistically equivalent in the two groups of patients. In the whole-group of responder patients, a perfusion decrease was found after rTMS, in comparison to non-responders, within the left perirhinal cortex (BA35, BA36). This result was secondarily confirmed separately in the two subgroups, i.e. after either left stimulation (p=0.017) or right stimulation (p<0.001), without significant perfusion differences between these two subgroups. CONCLUSIONS These data show that distinct successful rTMS protocols induce equivalent brain functional changes associated to antidepressive efficiency, consisting to a remote brain limbic activity decrease within the left perirhinal cortex. However, these results will have to be confirmed in a double-blind randomized trial using a sham control group.

Chocolate Intake Associated with Failed Labeling of 99mTc Red Blood Cells

Red blood cells (RBC) labeled in vivo with 99mTc-pertechnetate are used worldwide in nuclear medicine departments. Methods: Here, we present a case of 99mTc-RBC labeling failure associated with chocolate intake in a 25-y-old woman, resulting in uninterpretable images. Because of this clinical observation, we performed in vitro RBC labeling on blood samples from volunteers after they consumed chocolate. Results: Chocolate intake inhibited the labeling rate, compared with the control condition, and significantly increased the 99mTc free fraction (34.1% ± 11.3% vs. 14.0% ± 1.2%). Conclusion: We cannot explain how this interaction could occur, but cacao components are known to modulate red cell and plasma oxidoreductive status and to modify red cell membrane permeability and plasticity. Therefore, for patients who can be considered likely to consume chocolate, such as young patients, we recommend that they limit their consumption of chocolate for 12 h before RBC labeling.

FDG-PET to predict different patterns of progression in multicentric glioblastoma: a case report

True multicentric glioblastoma multiforme (GBM) is rare and consists of separate distinct tumors in different cerebral lobes or hemispheres without any apparent route of dissemination. Few data are available describing its imaging using positron emission tomography (PET) with [18F]-fluoro-2-deoxy-d-glucose (FDG). In this paper, we report on the case of a man with bifocal tumor in the right frontal and temporal lobes who underwent FDG-PET imaging. Visual and semiquantitative analysis showed two different metabolic patterns with much more intense uptake in the smaller temporal lesion. Subtotal surgical removal of the main frontal lesion allowed satisfactory control in the operative site, whereas the temporal lesion was rapidly progressive with occurrence of necrosis, which led to a second neurosurgery. The diagnosis of glioblastoma was confirmed by neuropathological examination in both cases but with much higher immunohistochemical expression of O6-methylguanine-DNA-methyltransferase (MGMT) in the temporal lesion. This report illustrates the potential interest of FDG-PET in multicentric GBMs to identify different metabolic patterns, in accordance with clinical, morphological, and molecular aggressiveness.

FDG PET and evaluation of posttherapeutic residual tumors in pediatric oncology: preliminary experience.

Introduction Residual masses are an important problem in oncology. The determination of their nature (fibrosis or active tumor) is crucial. The place of 18F-fluorodeoxyglucose -positron emitting tomography (PET) as a new imaging device remains to be determined in this context. Objectives To evaluate the place of 18F-fluorodeoxyglucose -PET in the prediction of the nature of residual masses in children with solid tumors. Patients and Methods Between January 2004 and January 2006, 238 PETs were performed in children followed up in the pediatric oncology and hematology departments. This was a monocentric retrospective review of the medical files of 18 children, in whom the main objective of the PET was to evaluate a residual mass. The sex ratio was 1/5; the median age 100 months (range, 34 to 180 mo). The underlying diseases were Hodgkin disease (n=5), lymphomas (n=5), osteosarcomas (n=3), rhabdomyosarcomas (n=2), and others (n=3). The final diagnostic (remission or persistent disease) was given by follow-up (median, 18 mo; range, 18 to 40), together with clinical, radiologic, and biopsy (in 6 cases) data. Results PET was negative in 13 cases and positive in 5, among them 4 patients relapsed. Among the 13 negative PETs, there was 1 relapse and 12 remissions. The respective value of PET sensibility and specificity were0.8 and 0.92, respectively. Positive and negative predictive values were 0.8 and 0.92, respectively. Conclusion On the basis of these preliminary results, PET seems to be an interesting tool to assess the nature of posttherapeutic residual masses in children, regardless of the underlying malignancy. Its role needs to be confirmed and further explored by multicentric studies tailored according to the underlying disease.