Prospective assessment of aneurysmal rupture risk scores in patients with subarachnoid hemorrhage: a multicentric cohort.

PURPOSE: The natural evolution of unruptured intracranial aneurysms (UIA) is indeed difficult to predict at the individual level. OBJECTIVE: In a large prospective multicentric European cohort, we aimed to evaluate whether the PHASES, UCAS, and ELPASS scores in patients with aneurysmal subarachnoid hemorrhage would have predicted a high risk of aneurysmal rupture or growth. METHODS: Academic centers treating patients with intracranial aneurysms were invited to prospectively collect de-identified data from all patients admitted at their institution for a subarachnoid hemorrhage-related to intracranial aneurysmal rupture between January 1 and March 31, 2021 through a trainee-led research collaborative network. Each responding center was provided with an electronic case record form (CRF) which collected all the elements of the PHASES, ELAPSS, and UCAS scores. RESULTS: A total of 319 patients with aneurysmal subarachnoid hemorrhage were included at 17 centers during a 3-month period. One hundred eighty-three aneurysms (57%) were less than 7 mm. The majority of aneurysms were located on the anterior communicating artery (n = 131, 41%). One hundred eighty-four patients (57%), 103 patients (32%), and 58 (18%) were classified as having a low risk of rupture or growth, according to the PHASES, UCAS, and ELAPSS scores, respectively. CONCLUSION: In a prospective study of European patients with aneurysmal subarachnoid hemorrhage, we showed that 3 common risk-assessment tools designed for patients with unruptured intracranial aneurysms would have not identified most patients to be at high or intermediate risk for rupture, questioning their use for decision-making in the setting of unruptured aneurysms.

Safety and Efficacy of Cangrelor in Acute Stroke Treated with Mechanical Thrombectomy: Endovascular Treatment of Ischemic Stroke Registry and Meta-analysis.

BACKGROUND AND PURPOSE: Rescue therapies are increasingly used in the setting of endovascular therapy for large-vessel occlusion strokes. Among these, cangrelor, a new P2Y12 inhibitor, offers promising pharmacologic properties to join the reperfusion strategies in acute stroke. We assessed the safety and efficacy profiles of cangrelor combined with endovascular therapy in patients with large-vessel-occlusion stroke. MATERIALS AND METHODS: We performed a retrospective patient data analysis in the ongoing prospective multicenter observational Endovascular Treatment in Ischemic Stroke Registry in France from July 2018 to December 2020 and conducted a systematic review and meta-analysis using several data bases. Indications for cangrelor administration were rescue strategy in case of refractory intracranial occlusion with or without intracranial rescue stent placement, and cervical carotid artery stent placement in case of cervical occlusion (tandem occlusion or isolated cervical carotid occlusion). RESULTS: In the clinical registry, 44 patients were included (median initial NIHSS score, 12; prior intravenous thrombolysis, 29.5%). Intracranial stent placement was performed in 54.5% (n = 24/44), and cervical stent placement, in 27.3% (n = 12/44). Adjunctive aspirin and heparin were administered in 75% (n = 33/44) and 40.9% (n = 18/44), respectively. Rates of symptomatic intracerebral hemorrhage, parenchymal hematoma, and 90-day mortality were 9.5% (n = 4/42), 9.5% (n = 4/42), and 24.4% (n = 10/41). Favorable outcome (90-day mRS, 0-2) was reached in 51.2% (n = 21/41), and successful reperfusion, in 90.9% (n = 40/44). The literature search identified 6 studies involving a total of 171 subjects. In the meta-analysis, including our series data, symptomatic intracerebral hemorrhage occurred in 8.6% of patients (95% CI, 5.0%-14.3%) and favorable outcome was reached in 47.6% of patients (95% CI, 27.4%-68.7%). The 90-day mortality rate was 22.6% (95% CI, 13.6%-35.2%). Day 1 artery patency was observed in 89.7% (95% CI, 81.4%-94.6%). CONCLUSIONS: Cangrelor offers promising safety and efficacy profiles, especially considering the complex endovascular reperfusion procedures in which it is usually applied. Further large prospective data are required to confirm these findings.

Large artery intracranial stenosis in young adults with ischaemic stroke.

Large artery intracranial stenosis (ICS) is a common finding in stroke patients, but is much less prevalent in Western countries than in Asia and in young adults than in the elderly. We investigated the prevalence and causes of ICS among French young adults with ischaemic stroke. Clinical and radiological data of patients aged 18-54 years treated consecutively for acute ischaemic stroke in the anterior circulation at a tertiary stroke centre were analysed retrospectively. Patients with>50% ICS were identified. ICS was evaluated using TOF-MRA, vessel wall-MRI, digital subtraction angiography and CT-angiography. A total of 316 patients were included. ICS was diagnosed in 29 patients, resulting in a prevalence of 9.2% (95% CI, 6.2 to 13.3). The leading cause of ICS was atherosclerosis (n=13), ahead of moyamoya disease (n=4), dissection (n=2), vasculitis (n=2), and reversible cerebral vasoconstriction syndrome (n=1). The cause of ICAS could not be determined in 7 patients. ICS was found in nearly one in 10 ischaemic strokes among French young adults. Atherosclerosis was the leading cause of ICS. The cause of ICS could not be determined in almost a quarter of the patients.

A Multicenter Preliminary Study of Cangrelor following Thrombectomy Failure for Refractory Proximal Intracranial Occlusions.

BACKGROUND AND PURPOSE: Rescue endovascular and pharmacologic approaches are increasingly being adopted after recanalization failure of acute large-vessel occlusion strokes with mechanical thrombectomy, with encouraging results. The safety and efficacy of glycoprotein IIb/IIIa inhibitors in ischemic stroke have been investigated, though cangrelor, a recent intravenous P2Y12-receptor inhibitor with a rapid onset/offset of action and a short half-life, may be a valuable option. We compared the safety and efficacy of cangrelor with those of glycoprotein IIb/IIIa inhibitors for refractory occlusions. MATERIALS AND METHODS: We performed a retrospective analysis of the ongoing prospective, multicenter, observational Endovascular Treatment in Ischemic Stroke Registry in France between May 2012 and February 2020. Refractory intracranial occlusions of the anterior and posterior circulation were included and defined as recanalization failure of large-vessel occlusion stroke, perioperative target artery reocclusion, or high risk of early reocclusion related to an arterial wall lesion. The primary end point was a favorable outcome, defined as a 90-day mRS of 0-2. Secondary end points were reperfusion, intracranial hemorrhage, and procedural complications. RESULTS: Among 69 patients, 15 were treated with cangrelor, and 54, with glycoprotein IIb/IIIa inhibitors. The favorable outcome (adjusted OR = 2.22; 95% CI, 0.42-11.75; P = .348) and mortality (adjusted OR = 0.44; 95% CI, 0.06-3.16; P = .411) rates were similar in both groups. There was no difference in the rates of any intracranial hemorrhage (adjusted OR = 0.40; 95% CI, 0.08-2.09; P = .280), symptomatic intracranial hemorrhage (6.7% versus 0.0%, P = .058), or procedural complications (6.7% versus 20.4%, P = .215). Reperfusion rates were higher in the cangrelor group, though the difference did not reach statistical significance (93.3% versus 75.0% for modified TICI 2b-3; adjusted OR =10.88; 95% CI, 0.96-123.84; P = .054). CONCLUSIONS: Cangrelor seems to be as safe as glycoprotein IIb/IIIa inhibitors for managing refractory intracranial occlusion and leads to satisfactory brain reperfusion. Cangrelor is a promising agent in this setting, and additional studies are warranted to confirm our findings.

Should CT angiography of the supra-aortic arteries be performed systematically following attempted suicide by hanging?

PURPOSE: Characterize and determine the frequency of dissections of the supra-aortic arteries (SAA) and injuries to the cervical spine and pharyngolaryngeal cartilages viewed on CT scans after an attempted suicide by hanging. MATERIALS AND METHODS: A retrospective, single-centre study of all patients admitted for attempted suicide by hanging between January 2010 and June 2017 who received CT angiography of the SAA. Search for signs of dissection of the cervical arteries and injuries to the brain, spinal column and pharyngeal and laryngeal cartilages. The results were compared with the initial clinical severity, which was assessed indirectly by whether patients were initially admitted in an intensive care unit (ICU) or in an emergency department (ED). RESULTS: Out of 162 patients included, 4 presented with SAA dissection (2.5%), comprising 3 vertebral arteries and 1 external carotid artery. The cases in question were of 4 men, all in cardiac arrest on arrival and all were treated in ICU. Of the most serious cases, 18/72 (25%) had anoxia-related injuries and one also presented with a C2 fracture. No vascular lesions or signs of cerebral anoxia were observed in the 90 ED patients. Nevertheless, pharyngeal and laryngeal fractures were observed in both groups, with no significant difference. CONCLUSION: In our study, 2.5% of CT angiograms performed after an attempted hanging revealed SAA dissection. Crucially, only most severe patients, who have been immediately admitted to ICU suffered SAA. These results call into question the systematic indication of this exam in cases of hanging attempts.

Standard Diffusion-Weighted Imaging in the Brain Can Detect Cervical Internal Carotid Artery Dissections.

BACKGROUND AND PURPOSE: The ICA is the most common site of cervical artery dissection. Prompt and reliable identification of the mural hematoma is warranted when a dissection is clinically suspected. The purpose of this study was to assess to capacity of a standard DWI sequence acquired routinely on the brain to detect dissecting hematoma related to cervical ICA dissections. MATERIALS AND METHODS: This was a retrospective study of a cohort of 110 patients younger than 55 years of age (40 women; mean age, 46.79 years) admitted at the acute phase of a neurologic deficit, headache, or neck pain and investigated by at least a standard 3T diffusion-weighted sequence of the brain. Among them were 50 patients (14 women; mean age, 46.72 years) with subsequently confirmed ICA dissection. In the whole anonymized cohort, both a senior and junior radiologist separately assessed, on the DWI sequences only, the presence of a crescent-shaped or circular hypersignal projecting on the subpetrosal segment of the ICA arteries, assuming that it would correspond to a mural hematoma related to an ICA dissection. RESULTS: The senior radiologist found 46 subpetrosal hyperintensities in 43/50 patients with ICA dissection and none in patients without dissection (sensitivity, 86%; specificity, 100%). The junior radiologist found 48 subpetrosal hyperintensities in 45/50 patients with dissection and none in patients without dissection (sensitivity, 90%; specificity, 100%). CONCLUSIONS: In our cohort, a standard DWI sequence performed on the brain at the acute phase of a stroke or for a clinical suspicion of dissection detected nearly 90% of cervical ICA dissections.

18FDG PET/CT in the early assessment of non-small cell lung cancer response to immunotherapy: frequency and clinical significance of atypical evolutive patterns.

PURPOSE: This prospective study aimed (1) to assess the non-small cell lung cancer (NSCLC) evolutive patterns to immunotherapy using FDG-PET and (2) to describe their association with clinical outcome. DESIGN: Fifty patients with metastatic NSCLC were included before pembrolizumab or nivolumab initiation. FDG-PET scan was performed at baseline and after 7 weeks of treatment (PETinterim1) and different criteria/parameters of tumor response were assessed, including PET response criteria in solid tumors (PERCIST). If a first PERCIST progressive disease (PD) without clinical worsening was observed, treatment was continued and a subsequent FDG-PET (PETinterim2) was performed at 3 months of treatment. Pseudo-progression (PsPD) was defined as a PERCIST response/stability on PETinterim2 after an initial PD. If a second PERCIST PD was assessed on PETinterim2, a homogeneous progression of lesions (termed immune homogeneous progressive-disease: iPDhomogeneous) was distinguished from a heterogeneous evolution (termed immune dissociated-response: iDR). A durable clinical benefit (DCB) of immunotherapy was defined as treatment continuation over a 6-month period. The association between PET evolutive profiles and DCB was assessed. RESULTS: Using PERCIST on PETinterim1, 42% (21/50) of patients showed a response or stable disease, most of them (18/21) reached a DCB. In contrast, 58% (29/50) showed a PD, but more than one-third (11/29) were misclassified as they finally reached a DCB. No standard PETinterim1 criteria could accurately distinguished responding from non-responding patients. Treatment was continued in 19/29 of patients with a first PERCIST PD; the subsequent PETinterim2 demonstrated iPDhomogeneous, iDR and PsPD in 42% (8/19), 26% (5/19), and 32% (6/19), respectively. Whereas no patients with iPDhomogeneous experienced a DCB, all patients with iDR and PsPD reached a clinical benefit to immunotherapy. CONCLUSION: In patients with a first PD on PERCIST and treatment continuation, a subsequent PET identifies more than half of them with iDR and PsPD, both patterns being strongly associated with a clinical benefit of immunotherapy.

Percutaneous transluminal angioplasty alone versus stent placement for the treatment of transplant renal artery stenosis.

PURPOSE: The purposes of this retrospective study were to assess the efficacy of endovascular techniques for the treatment of transplant renal artery stenosis (TRAS) by analyzing technical and clinical success and to compare the results of percutaneous transluminal angioplasty (PTA) alone to those of stenting. MATERIALS AND METHODS: A retrospective analysis was conducted on 31 patients who underwent endovascular treatment for TRAS between January 2012 and December 2017. There were 23 men and 8 women with a mean age of 60.5±14 (SD) years (range: 24-81 years). Ten patients (10/31; 32%; 8 men, 2 women; median age, 63 years) were treated with PTA alone and 21/31 (68%; 15 men, 6 women; median age, 65 years) with metallic stent placement. Several variables including serum creatinine level, glomerular filtration rate, arterial blood pressure value, antihypertensive medication obtained before and after treatment were compared. Technical success was assessed for each procedure. Clinical success was defined as a 15% drop in serum creatinine level, a decrease greater than 15% in mean blood pressure values or a decrease greater than 10% in mean blood pressure values with a reduction in the number of antihypertensive drugs needed for hypertension control. RESULTS: Technical success was obtained in all patients [31/31; 100%; 95% confidence interval (CI): 89-100%] and clinical success in 27/31 patients (87%; 95%CI: 71-95%). Four patients (4/31; 13%; 95%CI: 5-29%) underwent repeat endovascular intervention. Mean serum creatinine level and mean arterial blood pressure values were significantly lower after treatment (177.4 and 93.8µmol/l, respectively) compared to before treatment (319.4 and 106.7µmol/l, respectively) in the stent group but not in the group treated with PTA alone (P=0.0012 and P=0.002, respectively). CONCLUSION: The endovascular approach is safe and effective in the management of TRAS and stenting, depending on the morphology of the stenosis, should be the treatment of choice when possible.

MRI Quantitative T2* Mapping to Predict Dominant Composition of In Vitro Thrombus.

BACKGROUND AND PURPOSE: MR imaging quantitative T2* mapping, which provides information about thrombus composition and specifically the red blood cell content, may be obtained in the setting of acute ischemic stroke before treatment. This could be useful to adapt the endovascular strategy. We aimed to analyze the red blood cell content of in vitro thrombi in relation to the thrombus-T2* relaxation time. MATERIALS AND METHODS: Thirty-five thrombus analogs of different compositions were scanned with an MR imaging quantitative T2* mapping sequence. Two radiologists, blinded to thrombus composition, measured the thrombus-T2* relaxation time twice at an interval of 2 weeks. Quantitative histologic evaluations of red blood cell content were performed. Inter- and intraobserver reproducibility of the thrombus-T2* relaxation time was assessed by calculating intraclass correlation coefficients. Finally, a Spearman product moment correlation between the thrombus-T2* relaxation time and red blood cell content was performed. RESULTS: The median thrombus-T2* relaxation time was 78.5 ms (range, 16-268 ms; interquartile range, 60.5 ms). The median red blood cell content was 55% (range, 0%-100%; interquartile range, 75%). Inter- and intraobserver reproducibility of the thrombus-T2* relaxation time was excellent (>0.9). The Spearman rank correlation test found a significant inverse correlation between thrombus-T2* relaxation time and red blood cell content (ρ = -0.834, P < .001). CONCLUSIONS: MR imaging quantitative T2* mapping can reliably identify the thrombus red blood cell content in vitro. This fast, easy-to-use sequence could be implemented in routine practice to predict stroke etiology and adapt devices or techniques for endovascular treatment of acute ischemic stroke.

Surgical guidance by freehand SPECT for sentinel lymph node biopsy in early stage breast cancer: A preliminary study.

OBJECTIVE: Sentinel lymph node biopsy (SLNB) is a standard for patients with early breast cancer. Using a gamma-detecting probe connected to an infrared camera, the Declipse freehand SPECT (FhSPECT) system (Surgiceye(®)) is able to detect and locate any radioactive source in 3D. The objective of this study was to evaluate the potential interest of FhSPECT imaging for real-time guidance SLNB in breast cancer. METHODS: A prospective single-center clinical study assessed sensitivity and usability of FhSPECT for SLN detection and surgical guidance in breast cancer patients. SLN detection rate with FhSPECT was compared with lymphoscintigraphy (LS) and colorimetric method. Durations of FhSPECT acquisitions and of the SLNB procedure were measured in order to evaluate the practicability of the device. RESULTS: Between May and September 2014, 20 patients with early stage invasive breast cancer (cT0-2N0) underwent SLNB using FhSPECT and blue dye detection. Preoperative LS revealed 41 radioactive axillary SLNs (median=2 SLN per patient; range 0-4) in 20 patients. Preoperative FhSPECT detected 40 axillary SLNs (median=2; range: 1-4) in 20 patients. The corresponding sensitivity of FhSPECT was 97.5%. For 4 patients (20%), FhSPECT detected more axillary SLNs than LS. The colorimetric method identified only 24 axillary SLNs (2 patients had no blue dye injection on account of a history of allergy), leading to a sensitivity of 67% (24 blue SLNs/36 resected SLNs after blue dye injection). Median duration of FhSPECT acquisitions was 5minutes (range: 1-26min). Median duration of SLNB procedure was 11.5minutes (range: 3-55min). Duration of acquisitions analysis based on the number of use of the device showed decreasing values suggesting the existence of a short learning curve. CONCLUSION: This study demonstrated that FhSPECT is feasible and facilitates SLN identification.

[Sentinel node detection using optonuclear probe (gamma and fluorescence) after green indocyanine and radio-isotope injections]. / Détection du ganglion sentinelle dans le cancer du sein par sonde opto-nucléaire après injection de vert indocyanine et de technétium 99m.

OBJECTIVE: Assess the biopsy's feasibility of the sentinel lymph node biopsy (SLNB) using optonuclear probe after of indocyanine green (ICG) and radio-isotope (RI) injections. METHODS: Twenty-one patients with a localized breast cancer and unsuspicious axillary nodes underwent a SLNB after both injections of ICG and radio-isotope. RESULTS: One or more SLN were identified on the 21 patients (identification rate of 100%). The median number SLN was 2 (1-3). Twenty SLN were both radio-actives and fluorescents (54.1%), 11 fluorescent only (29.7%) and 6 were only radio-actives (16.2%). Seven patients had a metastatic SLN (8 SLN overall). Among them, only one had a micrometastasic SLN, 5 others had a macrometastatic SLN and one patient had two macrometastatic SLNs. Among the 8 metastatic SLN, 5 were both fluorescent and radioactive, 2 were only fluorescent and 1 was only radioactive. CONCLUSION: Detection SLN using optonuclear probe after indocyanine green and radio-isotope injections is effective and could be, after validation by randomized trial, a reliable alternative to the blue dye injection for teams who consider that combined detection as the reference.

Cognitive and functional patterns of nondemented subjects with equivocal visual amyloid PET findings.

PURPOSE: Despite good to excellent inter-reader agreement in the evaluation of amyloid load on PET scans in subjects with Alzheimer's disease, some equivocal findings have been reported in the literature. We aimed to describe the clinical characteristics of subjects with equivocal PET images. METHODS: Nondemented subjects aged 70 years or more were enrolled from the MAPT trial. Cognitive and functional assessments were conducted at baseline, at 6 months, and annually for 3 years. During the follow-up period, 271 subjects had (18)F-AV45 PET scans. Images were visually assessed by three observers and classified as positive, negative or equivocal (if one observer disagreed). After debate, equivocal images were reclassified as positive (EP+) or negative (EP-). Scans were also classified by semiautomated quantitative analysis using mean amyloid uptake of cortical regions. We evaluated agreement among the observers, and between visual and quantitative assessments using kappa coefficients, and compared the clinical characteristics of the subjects according to their PET results. RESULTS: In 158 subjects (58.30 %) the PET scan was negative for amyloid, in 77 (28.41 %) the scan was positive and in 36 (13.28 %) the scan was equivocal. Agreement among the three observers was excellent (kappa 0.80). Subjects with equivocal images were more frequently men (58 % vs. 37 %) and exhibited intermediate scores on cognitive and functional scales between those of subjects with positive and negative scans. Amyloid load differed between the EP- and negative groups and between the EP+ and positive groups after reclassification. CONCLUSION: Equivocal amyloid PET images could represent a neuroimaging entity with intermediate amyloid load but without a specific neuropsychological pattern. Clinical follow-up to assess cognitive evolution in subjects with equivocal scans is needed.

[Freehand SPECT for navigation and sentinel node detection in breast cancer]. / Intérêt du repérage per-opératoire 3D des ganglions sentinelles dans le cancer du sein.

The sentinel lymph node (SLN) is a standard for the surgical treatment of axillary localized breast cancer N0. It is based on a double isotopic and color detection. With a gamma detecting probe connected to an infrared camera, Déclipse SPECT system (Surgiceye(®)) is able to detect and locate any radioactive source in 3D. Mobile character for use in the operating room is particularly interesting for the intraoperative detection of SLN. We illustrate its usefulness in a clinical case where the preoperative identification of SLN by lymphoscintigraphy was not informative.

18F-FDOPA PET for the diagnosis of parkinsonian syndromes.

18F-FDOPA PET has been historically used for the evaluation of parkinsonian syndromes in research settings. With the wider availability of PET cameras and 18F-DOPA this method can be used as a clinical diagnostic tool. Current acquisition protocols are simple with a 10 minute static acquisition performed 90 minutes post injection. Criteria for precise visual analysis of the images are defined. The performances of the method are reviewed throughout the literature. The method is very sensitive for detection of IPD versus normal patients. Few studies comparing 18F-FDOPA PET and DAT SPECT did not show any difference in diagnostic accuracy. 18F-FDOPA PET is reliable for evaluation of IPD progression. In general, atypical Parkinson's syndromes cannot be reliably differentiated from IPD since they share a similar nigro-striatal degeneration process. However, some patterns such as the asymmetrical faint homogeneous striatal uptake reduction pattern of CBD can be recognized. The short acquisition protocol, the various indications in oncology of 18F-FDOPA and the high quality of PET images are in favor of this technique in daily clinical practice for the improvement of diagnosis of parkinsonian syndromes.

[Sentinel node biopsy in breast cancer using magnetic tracer: preliminary study]. / Technique d'identification du ganglion sentinelle dans le cancer du sein par traceur magnétique : étude préliminaire.

OBJECTIVE: To evaluate the feasibility of the magnetic technique for sentinel node biopsy (SNB) in breast cancer. PATIENTS AND METHODS: A total of 10 consecutives patients with breast cancer scheduled for SNB, who were clinically node negative, were recruited. SNB was undertaken after injection of both magnetic and radio-isotopic tracers. RESULTS: One or more SN were identified among 10 patients (identification rate of 100%). The median number of GS taken was 1.7 (range 1-3). In total, 17 GS were taken. SN were radioactive and ferromagnetic (82.3%), 3 were only radioactive and none was only ferromagnetic. DISCUSSION AND CONCLUSION: The magnetic technique is feasible, but cannot be used alone due to technical constraints.

Amplitude-based data selection for optimal retrospective reconstruction in micro-SPECT.

Respiratory motion can blur the tomographic reconstruction of positron emission tomography or single-photon emission computed tomography (SPECT) images, which subsequently impair quantitative measurements, e.g. in the upper abdomen area. Respiratory signal phase-based gated reconstruction addresses this problem, but deteriorates the signal-to-noise ratio (SNR) and other intensity-based quality measures. This paper proposes a 3D reconstruction method dedicated to micro-SPECT imaging of mice. From a 4D acquisition, the phase images exhibiting motion are identified and the associated list-mode data are discarded, which enables the reconstruction of a 3D image without respiratory artefacts. The proposed method allows a motion-free reconstruction exhibiting both satisfactory count statistics and accuracy of measures. With respect to standard 3D reconstruction (non-gated 3D reconstruction) without breathing motion correction, an increase of 14.6% of the mean standardized uptake value has been observed, while, with respect to a gated 4D reconstruction, up to 60% less noise and an increase of up to 124% of the SNR have been demonstrated.

The sentinel lymph node procedure for patients with preoperative diagnosis of ductal carcinoma in situ: risk factors for unsuspected invasive disease and for metastatic sentinel lymph nodes.

BACKGROUND: Occult invasive disease could be found at definitive histology in patients initially diagnosed with large ductal carcinoma in situ (DCIS). Sentinel lymph node (SLN) biopsy is a reliable and minimally invasive procedure providing axillary information and avoiding a second operation in this particular group of patients. The aim of our study was to assess the value of SLN biopsy in patients with large DCIS who are at highest risk for being upstaged to invasive carcinoma. PATIENTS AND METHODS: The study included 195 patients diagnosed with DCIS upon initial core biopsy and undergoing SLN biopsy. Many features were correlated with the presence of unsuspected invasive disease and positive SLN biopsy using univariate and multivariate analyses. RESULTS: Of the 110 patients with pure DCIS, seven patients (6%) had a metastatic lymph node; 31 patients (16%) were found to have invasive disease upon final histology. Univariate analysis of predictors of unsuspected invasive carcinoma showed that patients having a preoperative biopsy that indicated DCIS with microinvasion (DCISM) or large DCIS were at a higher risk of invasive carcinoma after histological examination of the operative specimen. Of the 31 patients who were upstaged to invasive carcinoma at final histology, seven patients (22%) had a positive SLN biopsy. The analysis of predictors of positive SLN in our study shows that diffuse DCIS requiring mastectomy is the main risk factor for SLN metastasis. CONCLUSION: There are no real predictive factors for invasive disease in patients with an initial diagnosis of DCIS or DCISM. Our study supports the value of SLN biopsy in patients with a preoperative DCISM biopsy or patients with a large pure DCIS biopsy requiring mastectomy.

Model-based respiratory motion compensation for emission tomography image reconstruction.

In emission tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity distribution in lungs lesions, but which have the disadvantages of requiring additional instrumentation or the need of discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion compensation directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the maximum likelihood expectation maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data.

99mTc-HMPAO and 99mTc-ECD brain uptake correlates of verbal memory in Alzheimer's disease.

AIM: Technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO) and technetium-99m N,N-1,2-ethylene diylbis-Lcysteine diethyl ester dihydrochloride ((99m)Tc-ECD) SPECT are widely used in Dementia Clinics for early and differential diagnosis. They have been shown to perform differently in Alzheimer's disease (AD), but the impact of such differences on both research and clinical work is unknown. We investigated the differences between the 2 compounds in research work by assessing correlation between performance on a verbal memory task and cerebral perfusion in 2 matched groups of AD patients. METHODS: Nineteen pairs of patients with mild to moderate AD undergoing SPECT with either 99mTc-HMPAO or (99m)Tc-ECD were retrospectively selected in a Memory Clinic. Patients were matched for sex, age (+/-3 years) and the Mini-Mental State Examination score (+/-2 points) with a case-control procedure, thus obtaining 2 well-matched groups. The score on the Grober-Buschke selective reminding test (SRT) was correlated with SPECT in each group by means of statistical parametric mapping 99 (height threshold: P<0.01). RESULTS: (99m)Tc-HMPAO SPECT yielded 3 significant correlation clusters involving inferior and middle frontal gyri, para-hippocampal gyrus and putamen in the right hemisphere; the middle and superior temporal gyri, insula and claustrum in the left hemisphere. (99m)Tc-ECD gave a significant cluster of correlation in left postcentral gyrus and inferior parietal lobule. CONCLUSION: (99m)Tc-HMPAO SPECT correlation sites seem more consistent than (99m)Tc-ECD ones with the neurophysiological models of verbal memory, as designed both in normal individuals and in pathological conditions. The demonstration of such relevant differences introduces a source of variability among studies performed with either of the 2 compounds, which must be considered when interpreting results.

From the molecular characterization of iodide transporters to the prevention of radioactive iodide exposure.

In the event of a nuclear reactor accident, the major public health risk will likely result from the release and dispersion of volatile radio-iodines. Upon body exposure and food ingestion, these radio-iodines are concentrated in the thyroid, resulting in substantial thyroidal irradiation and accordingly causing thyroid cancers. Stable potassium iodide (KI) effectively blocks thyroid iodine uptake and is thus used in iodide prophylaxis for reactor accidents. The efficiency of KI is directly related to the physiological inhibition of the thyroid function in the presence of high plasma iodide concentrations. This regulation is called the Wolff-Chaikoff effect. However, to be fully effective, KI should be administered shortly before or immediately after radioiodine exposure. If KI is provided only several hours after exposure, it will elicit the opposite effect e.g. lead to an increase in the thyroid irradiation dose. To date, clear evaluation of the benefit and the potential toxicity of KI administration remain difficult, and additional data are needed. We outline in this review the molecular characterization of KI-induced regulation of the thyroid function. Significant advances in the knowledge of the iodide transport mechanisms and thyroid physiology have been made. Recently developed molecular tools should help clarify iodide metabolism and the Wolff-Chaikoff effect. The major goals are clarifying the factors which increase thyroid cancer risk after a reactor accident and improving the KI administration protocol. These will ultimately lead to the development of novel strategies to decrease thyroid irradiation after radio-iodine exposure.