Dosimetric impact of switching from AAA to Acuros dose-to-water and dose-to-medium for RapidArc plans of nasopharyngeal carcinomas.

PURPOSE: This work aims to evaluate the dosimetric consequences of replacing the Anisotropic Analytical Algorithm (AAA) by Acuros XB (AXB), dose-to-water (Dw) or dose-to-medium (Dm), for RapidArc plans of nasopharyngeal carcinomas (NPC). MATERIALS AND METHODS: Seventeen NPC plans created with AAA (v15.6) were recalculated with AXB (v15.6) Dw and Dm. The dose-volume parameters to the planning target volumes (PTV) and relevant organs at risk (OAR) were compared. The high dose PTV was divided into bone, air and tissue components and the comparison was performed for each of them. RESULTS: AXB Dw revealed no significant differences in the PTVs compared to AAA. Lower values were observed to spinal cord, brainstem, oral cavity and parotids (0.5% to 2.3%), and higher values to cochleas (up to 5.4%) and mandible (up to 6.7%). AXB Dm predicted lower values than AAA for all PTVs and OARs (2.0% to 6.1%). For the bone PTV subvolume, AXB Dw and Dm predicted respectively higher (2.4%) and lower (2.2% to 3.4%) values. No significant differences were noted in air. AXB predicted lower values than AAA in soft tissues (0.4% to 1.6%). The largest difference was found to the mandible V60Gy parameter, with median differences of 6.7% for AXB Dw and -6.0% for AXB Dm. CONCLUSION: Significant dose differences are expected when switching from AAA to AXB in NPC cases. The dose prescriptions and the tolerance limits for some OARs, especially those of high density, may need to be adjusted depending on the selected dose calculation algorithm and reporting mode.

Collision prediction for intracranial stereotactic radiosurgery planning: An easy-to-implement analytical solution.

PURPOSE: Gantry collision is a concern in linac-based stereotactic radiosurgery (SRS). Without collision screening, the planner may compromise optimal planning, unnecessary re-planning delays can occur, and incomplete treatments may be delivered. To address these concerns, we developed a software for collision prediction based on simple machine measurements. MATERIALS AND METHODS: Three types of collision were identified; gantry-couch mount, gantry-couch and gantry-patient. Trigonometric formulas to calculate the distance from each potential point of collision to the gantry rotation axis were generated. For each point, collision occurs when that distance is greater than the gantry head to gantry rotational axis distance. The colliding arc for each point is calculated. A computer code incorporating these formulas was generated. The inputs required are the couch coordinates relative to the isocenter, the patient dimensions, and the presence or absence of a circular SRS collimator. The software outputs the collision-free gantry angles, and for each point, the shortest distance to the gantry or the colliding sector when collision is identified. The software was tested for accuracy on a TrueBEAM® machine equipped with BrainLab® accessories for 80 virtual isocenter-couch angle configurations with and without a circular collimator and a parallelepiped phantom. RESULTS: The software predicted the absence of collision for 19 configurations. The mean absolute error between the measured and predicted gantry angle of collision for the remaining 61 cases was 0.86 (0.01-2.49). CONCLUSION: This tool accurately predicted collisions for linac-based intracranial SRS and is easy to implement in any radiotherapy facility.

Measurement of the potential geographic accessibility from call to definitive care for patient with acute stroke.

BACKGROUND: The World Health Organization refers to stroke, the second most frequent cause of death in the world, in terms of pandemic. Present treatments are only effective within precise time windows. Only 10% of thrombolysis patients are eligible. Late assessment of the patient resulting from admission and lack of knowledge of the symptoms is the main explanation of lack of eligibility. METHODS: The aim is the measurement of the time of access to treatment facilities for stroke victims, using ambulances (firemen ambulances or EMS ambulances) and private car. The method proposed analyses the potential geographic accessibility of stroke care infrastructure in different scenarios. The study allows better considering of the issues inherent to an area: difficult weather conditions, traffic congestion and failure to respect the distance limits of emergency transport. RESULTS: Depending on the scenario, access times vary considerably within the same commune. For example, between the first and the second scenario for cities in the north of Rhône county, there is a 10 min difference to the nearest Primary Stroke Center (PSC). For the first scenario, 90% of the population is 20 min away of the PSC and 96% for the second scenario. Likewise, depending on the modal vector (fire brigade or emergency medical service), overall accessibility from the emergency call to admission to a Comprehensive Stroke Center (CSC) can vary by as much as 15 min. CONCLUSIONS: The setting up of the various scenarios and modal comparison based on the calculation of overall accessibility makes this a new method for calculating potential access to care facilities. It is important to take into account the specific pathological features and the availability of care facilities for modelling. This method is innovative and recommendable for measuring accessibility in the field of health care. This study makes possible to highlight the patients' extension of care delays. Thus, this can impact the improvement of patient care and rethink the healthcare organization. Stroke is addressed here but it is applicable to other pathologies.

[Oral cavity cancers among young people: Clinical results and prognostic analysis]. / Cancers de la cavité buccale chez les sujets jeunes: résultats thérapeutiques et analyse de facteurs pronostiques.

PURPOSE: Squamous cell carcinomas of the oral cavity occurring in young people represent a specific entity. Its management and prognosis are controversial. We performed a retrospective chart review of all patients aged less than 40 years old and treated at Gustave-Roussy Cancer Centre for a squamous cell carcinomas of the oral cavity between 1999 and 2011. METHODS: Patients and tumour characteristics, type of treatment and follow-up data were collected. Survival data were analysed according to the methods of Kaplan-Meier and both univariate and multivariate analyses were performed to look for prognostic factors regarding overall survival and progression-free survival. RESULTS: Sixty-three patients were identified. Median follow-up was 64 months. Most of the tumours were initially located in the mobile tongue (n=54, 85.7%). Overall 17 patients had died, including 15 from the treated cancer. Overall and progression-free survival rates at 5 years were respectively 79.6% and 68.6%. The corresponding 5 years local, regional and metastatic relapse free survival rates were 80%, 91% and 89% respectively. In the multivariate analysis only the absence of initial surgery (hazard ratio [HR]: 13.5 [2.0; 90.5]; P=0.007) was prognostic for overall survival, while alcohol abuse (HR: 0.37 [0.15; 0.9]; P=0.03) and the absence of surgery (HR: 13.6 [2.5; 74.2]; P=0.002) were associated with a decreased progression-free survival. A younger age (less than 30 year old) was not associated with the risk of recurrence or death. CONCLUSION: Survival rates and tumour control probabilities are relatively high among young patients suffering from squamous cell carcinomas of the oral cavity treated at a tertiary centre. The early identification of patients at risk of relapse is currently difficult. The balance between recurrence and treatment toxicity warrants further studies, both on the clinical level and for the development of prognostic biomarkers.

Meals served to hypertensive and cardiac inpatients in Jordan:comparison with WHO and NIH dietary guidelines

لقد هدفت هذه الدراسه الى تقييم الالتزام في الوجبات اليوميه التي تقدم لمرضى ارتفاع ضغط الدم ومرضى القلب المنومين في المستشفيات الاردنيه بالدلائل الارشادية لمنظمة الصحه العالميه وبخطط النظام الغذائي الواردة في التغيرات العلاجيه لنمط الحياة وفي النهج الغذائي الهادف الى وقف ارتفاع ضغط الدم ولقد اجري تحليل لقوائم الطعام الدوريه الاسبوعيه التي اخذت من اقسام خدمات الطعام في المستشفيات الكبرى في الاردن ( ع=16)وذلك باستخدام برنامج معالج الطعام إيشا ESHA للحصول على بيانات عن محتواها من المغذيات كبيره المقدار والمغذيات زهيدة المقدار وعن مجموعات الاغذيه الممثله فيها فأظهرت النتائج ان كميات العديد من المغذيات الواردة في القوائم المقدمة ليست ملائمه الى جانب عدم الالتزام - عموما - بخطط النظام الغذائي الواردة في النهج الغذائي الهادف الى وقف ارتفاع ضغط الدم وفي التغييرات العلاجيه لنمط الحياه بالدلائل الارشاديه لمنظمة الصحه العالميه فكان محتوى الوجبات من الصوديم اعلى من الموصى به الى جانب انخفاض محتواها من البوتاسيوم وكانت كميه الاحماض الدهنيه في الغالب خارج المجالات الموصى بها فالوجبات التى تقدم لمرضى القلب في مستشفيات الاردن بحاجة الى مراجعة كي تلبي الدلائل الارشاديه التي وضعت خصيصا لتناسب الظروف الصحيه لهؤلاء المرضى

This study aimed to evaluate the compliance of daily meals served to hypertensive and cardiac inpatients in Jordan according to WHO guidelines and the Therapeutic Lifestyle Changes (TLC) and Dietary Approach to Stop Hypertension (DASH) diets plans. Weekly cycle menus from the food service department of major hospitals in Jordan (n = 16) were analysed using ESHA Food Processor software to obtain data about macroand micronutrient contents and food groups represented. The results showed inappropriate amounts of several nutrients in the menus provided, along with a general noncompliance with the DASH, TLC and WHO guidelines.Meals had higher than recommended sodium content coupled with low potassium content. Fatty acid profiles were often outside the recommended ranges. Meals provided to cardiac inpatients in Jordan need to be revised to meet the guidelines specified for the health conditions of these patients.

La présente étude visait à évaluer dans quelle mesure les repas quotidiens servis aux patients hospitalisés atteints d’hypertension ou de cardiopathie en Jordanie respectaient les recommendations de l'Organisation mondiale de la Santé (OMS) et les régimes alimentaires Therapeutic Lifestyle Changes (TLC) et Dietary Approach toStop Hypertension (DASH). Les cycles hebdomadaires de menus du service de restauration des grands hôpitaux en Jordanie (n = 16) ont été analysés à l’aide du logiciel ESHA Food Processor pour obtenir des données sur la composition en macronutriments et en micronutriments ainsi que sur les groupes d’aliments représentés. Les résultats ont révélé des quantités inadaptées de plusieurs nutriments dans les menus servis, ainsi qu’un non-respect général des recommandations DASH, TLC et de l’OMS. Les repas avaient une composition en sodium trop élevée et un taux de potassium trop faible par rapport aux recommandations. Les profils des acides gras étaient souvent hors des plages recommandées. Les repas fournis aux patients hospitalisés atteints de cardiopathie en Jordanie doivent être revus pour répondre aux recommandations visant leurs pathologies.

[Evaluation of the management of COPD exacerbations: an audit in French emergency services]. / Prise en charge des exacerbations de BPCO : audit de pratique aux urgences.

INTRODUCTION: Acute exacerbations of chronic obstructive pulmonary disease (COPD) patients are major events in the history of this chronic respiratory disease. Their management in French emergency services is unknown, although national guidelines exist. METHODS: This is a descriptive audit study, over a 10 weeks period (12/01-22/03/2009), of the management of COPD exacerbations in the RESUVal (Réseau des Urgences de la Vallée du Rhône, France) network emergency departments. RESULTS: The enrollement of 16 emergency units allowed the analysis of 221 exacerbations of COPD. Measurement of respiratory rate and description of the sputum were mentioned in only 99 (45%) medical records. The rest of the initial assessment was generally satisfactory. Regarding the therapeutic management, 215 (97%) patients received oxygen, beta-2-agonist aerosols were administrated for 209 (95%) patients and anticholinergic aerosols were used for 176 (80%) patients. A systemic corticosteroid and antibiotics were respectively prescribed for 116 (52%) and 123 (56%) patients. Non-invasive ventilation (NIV) was used in only 59% of patients presenting a pH<7.35. CONCLUSIONS: These findings demonstrate that management of exacerbations of COPD could be improved through systematic patients' respiratory rate and sputum characteristics recording or NIV utilization reinforcement.

Is There Still a Role for Fibrinolysis in ST-Elevation Myocardial Infarction?

OPINION STATEMENT: Fibrinolysis had long been the reference treatment in patients with ST-Elevation Myocardial Infarction (STEMI). It was associated with a large reduction in mortality as compared with delayed or no reperfusion in patients managed early, within the first 2 hours from the onset of symptoms. Fibrinolysis also had well-known potential complications: cerebral haemorrhage, especially in patients beyond 75 years, and reinfarction. Primary percutaneous intervention (PCI) has overcome most of these limitations, but at a price: PCI-related delays that can reduce the expected benefit of primary PCI compared with fibrinolysis. That primary PCI is today the treatment of choice in patients with STEMI is no longer discussed. However, fibrinolysis should still maintain a role in the management of acute myocardial infarction (AMI) for three reasons. First, fibrinolysis is no longer a stand-alone treatment. Modern fibrinolytic strategies combine immediate fibrinolysis, loading dose of thienopyridines, and transfer to a PCI hospital for rescue or early PCI within 24 hours. These strategies capitalize on the hub-and-spoke networks that have, or should have, been built everywhere to implement primary PCI. The overall clinical results of these modern fibrinolytic strategies are now similar to those of primary PCI. Second, a substantial number of patients cannot be managed with primary PCI within the reasonable time thresholds set by the guidelines. In the case of long PCI-related delays, patients will benefit from fibrinolysis before or during transfer to a PCI hospital. Third, modern fibrinolytic strategies-immediate fibrinolysis followed by rescue or early PCI-may even offer the best results of all in a subset of patients. Patients of less than 75 years, managed within the first 2 hours and who cannot have immediate PCI, will fare better with a modern fibrinolytic strategy than with primary PCI. Guidelines advocate regional networks between hospitals with and without PCI capabilities, an efficient ambulance service and standardization of AMI management through shared protocols. These regional logistics of care are essential to take full advantage of fibrinolysis strategies. In order to check that these strategies are correctly applied, networks need ongoing registries, as well as benchmarking and quality improvement initiatives.

Vacuum-assisted biopsies under MR guidance: results of 72 procedures.

OBJECTIVE: To investigate the clinical accuracy of magnetic resonance imaging-guided breast vacuum-assisted biopsy (MR-VAB). METHODS: Of 97 scheduled MR-VAB for single MRI lesions (negative second-look sonography) categorised as BI-RADS 4 or 5, 4 were cancelled (undetected lesion = 2, technical problems = 2). Twenty-one patients lost to follow-up were excluded. RESULTS: Twenty-three patients (median age 51 years) were at high risk (BRCA1 = 11, BRCA2 = 7, familial risk = 5), 23 had a suspected local recurrence of breast cancer. Seventy-two imaged lesions (focus = 1, mass enhancement = 32, non-mass-like enhancement = 39) were targeted with a 10-gauge VAB probe using MRI guidance, with a median of 18 specimens per lesion (median procedural time 72 min, range 50-131 min) followed by clip placement. In the case of benignity, MRI follow-up was performed (19 patients, median 389 days, range 33-1,592) or mammography (3 patients, median 420 days, range 372-1,354). According to histopathology results, 29 lesions were benign, 10 were high-risk (papillary = 2, radial scar = 1, atypical epithelial hyperplasia = 7) and 33 malignant (ductal carcinoma in situ = 8, invasive cancers = 25). Three false negative results and 3 complications occurred (1 malaise, 1 skin defect, 1 infection). CONCLUSION: MRI-guided VAB represents an accurate tool for the histological diagnosis of lesions visible only at MRI.

[MR breast screening in patients with genetic mutation]. / Dépistage du cancer du sein par IRM chez les femmes porteuses d'une mutation génétique.

PURPOSE: To compare screening breast MRI with conventional screening techniques in high-risk patients with genetic mutation. MATERIALS AND METHODS: Prospective study of 85 patients (mean age of 43 years) with genetic mutation and screening > or = 2 years (mean of 2.7 years, 231 screening examinations). BI-RADS lesions 3-5 were biopsied; isolated BI-RADS 3 lesions on MRI were followed. Results from both techniques were compared. The number of short interval follow-up examinations and biopsy results were reviewed. RESULTS: Eight cancers were diagnosed (3 in situ, 5 invasive carcinomas including an interval cancer, mean size of 14 mm). The sensitivity values for mammography, US and MRI were 12.5%, 50% and 95%, and specificity values were 98.7%, 97.3% and 94.8% respectively. Nineteen short interval follow-up MRI examinations were performed (19%): 14% of patients at initial screening and 5% and 6% at the the second and third screenings. Thirty-two biopsies were performed in 17 patients, including 18 after MRI (PPV of cytology: 30%, and biopsy: 58%). CONCLUSION: Our results confirm the value of MRI for screening of high-risk patients with genetic mutation.

Vacuum-assisted large-core needle biopsy (VLNB) improves the management of patients with breast microcalcifications - analysis of 1009 cases.

AIMS: To evaluate the surgical management of patients who underwent VLNB for breast microcalcifications. METHODS: This retrospective study compared the histological results and the surgical procedures in two groups of patients, group 1: large-core needle biopsy n=1009, and group 2: surgical biopsy n=270. RESULTS: After VLNB, 54% patients were not operated on after stereotactic large-core needle biopsy, 42% underwent one operation, 4% underwent two operations and 0.2% underwent three operations. No surgery was performed for 95% of benign lesions. Multiples operations were necessary in 12% of patients with malignant lesions of VLNB group compared to 45% in the surgical biopsy group. The rate of underdiagnosis of borderline lesions and ductal carcinomas in situ was 16% by the large-core biopsy technique. CONCLUSION: VLNB constitutes an alternative to surgical biopsy. This procedure avoids surgery for most benign lesions and reduces the number of surgical procedures in malignant lesions.

[Elastography of the breast: a prospective study of 122 lesions]. / Elastosonographie du sein: étude prospective de 122 lésions.

OBJECTIVE: To evaluate elastography in the characterization of breast nodules. MATERIAL AND METHODS: Elastography (Hitachi, 7.5- to 13-MHz probe; Ueno classification, scores 1-3=benign, 4-5=malignant) was evaluated in 125 subclinical lesions in 114 patients. The results were compared to those of the ACR's BI-RADS sonography categories (benign=2 and 3, malignant=4 and 5) and to the results of the percutaneous samples taken and/or surgery (122 lesions evaluated, 59%<10 mm, 61 cancers, 61 benign lesions). RESULTS: There were three technical failures (2.4%). The elastography was in agreement with histology for 101 lesions, with 13 false-negative results and eight false-positive results (sensitivity, 78.7%; specificity, 86.9%; PPV, 85.7%; NPV, 80.3%); versus agreement with the BI-RADS classification for 98 lesions with one false-negative result and 23 false-positive results (sensitivity, 98.4%; specificity, 47.5%; PPV, 65.2%; NPV, 96.7%). CONCLUSION: Elastography is a simple and rapid complementary method that can improve the specificity and the PPV of morphological imaging studies of breast nodules with a low level of suspicion (BI-RADS categories 3 and 4a), which should decrease the rate of unnecessary benign biopsies.

[Usefulness of magnetic resonance imaging in Paget disease of the breast]. / Apport de l'IRM dans la maladie de Paget du sein.

OBJECTIVE: Evaluate the usefulness of MRI in local staging of Paget disease of the breast. MATERIALS AND METHODS: Clinical, radiological (mammographies, MRI), and histological data were analyzed in six female patients presenting Paget disease of the breast. The criteria for analysis in MRI were the following: morphology of the aureola-nipple plaque (thickening, regularity of the contour) and the type of enhancement after injection of contrast medium (signal intensity/time curve), detection of abnormal enhancing in the mammary gland, and ganglion areas. RESULTS: None of the patients presented a palpable mass or a suspicious anomaly on mammography. On MRI, the aureola-nipple plaque was morphologically abnormal in four cases, with suspicious enhancement in two cases (two cases of ductal carcinoma in situ) and normal enhancement in two cases (one case of ductal carcinoma in situ). In the two other cases, the aureola-nipple plaque was normal (one case of ductal carcinoma in situ). Distant abnormal enhancement of the aureola-nipple plaque was noted in two cases (one case of ductal carcinoma in situ and one benign lesion). CONCLUSION: The MRI aspect of the aureola-nipple plaque in Paget disease shows little concordance with the histological results. MRI can be useful in detecting distant lesions when there is no clinical sign nor a suspicious mammography.

[New developments in breast imaging]. / Quoi de neuf en imagerie du sein?

In 2004, breast cancer screening will be effective in France. This evolution has a strong impact on our mammographic practice that becomes a real mission of public health. Digital mammography, compared to screen-film mammography, provides the same results for the detection of breast cancer, computer-aided detection systems represent the most relevant application of this technology at this time. The setting up of a quality control will allow the introduction of this technology in screening during 2004. Percutaneous imaging-guided procedures are now currently used for the diagnosis of nonpalpable breast lesions and allow the selection of patients for surgery. These procedures have emphasized the need for a multidisciplinary approach of the patients. Indications of MRI have not changed because of its moderated specificity and no relevant development of interventional-guided procedures. Work on standardization of radiological reports and assessment categories goes on. This classification is already applied for mammography, and new classifications for lesions detected by ultrasound or MRI will be published by the American College of Radiology (Breast Imaging Reporting and Data System, 4th edition, available in 2003).

[Interventional radiology in nonpalpable lesions of the breast]. / Radiologie interventionnelle en pathologie mammaire.

The increasing number of nonpalpable breast lesions found at screening mammography has induced the development of percutaneous imaging-guided procedures to reduce the number of surgical biopsies. After a description of the indications (classification of the American College of Radiology), the different types of sampling procedures (fine needle aspiration, core and large-core biopsies) will be described and the material used also. Depending on the type of breast lesions (mass, clustered microcalcifications), ultrasound--guided and stereotactic--guided biopsies will be explained. Clear information to the patients, efficient quality control and multidisciplinary approach are mandatory for the success of these percutaneous diagnostic procedures.

[CT and MR image fusion using two different methods after prostate brachytherapy: impact on post-implant dosimetric assessment]. / Comparaison de deux méthodes de recalage d'images de scanographie et d'IRM en curiethérapie prostatique. Intérêt pour l'évaluation thérapeutique.

PURPOSE: To study different methods of CT and MR images fusion in patient treated by brachytherapy for localized prostate cancer. To compare the results of the dosimetric study realized on CT slices and images fusion. MATERIALS AND METHODS: Fourteen cases of patients treated by I125 were retrospectively studied. The CT examinations were realized with contiguous section of 5mm thickness, and MR images were obtained with a surface coil with contiguous section of 3 mm thickness. For the images fusion process, only the T2 weighted MR sequence was used. Two processes of images fusion were realized for each patient, using as reference marks the bones of the pelvis and the implanted seeds. A quantitative and qualitative appreciation was made by the operators, for each patient and both methods of images fusion. The dosimetric study obtained by a dedicated software was realized on CT images and all types of images fusion. The usual dosimetric indexes (D90, V100 and V150) were compared for each type of image. RESULTS: The quantitative results given by the software of images fusion showed a superior accuracy to the one obtained by the pelvic bony reference marks. Conversely, qualitative and quantitative results obtained by the operators showed a better accuracy of the images fusion based on iodine seeds. For two patients out of three presenting a D90 inferior to 145 Gy on CT examination, the D90 was superior to this norm when the dosimetry was based on images fusion, whatever the method used. CONCLUSION: The images fusion method based on implanted seed matching seems to be more precise than the one using bony reference marks. The dosimetric study realized on images fusion could allow to rectify possible errors, mainly due to difficulties in surrounding prostate contour delimitation on CT images.

The role of the dorsal columns in neuropathic behavior: evidence for plasticity and non-specificity.

Despite conflicting clinical and experimental evidence, textbook description of somatic sensations continues to follow a rigid dichotomy based on the concept that pain sensation is transmitted cephalad primarily through anterolateral pathways, while touch is mediated through the dorsal column pathway. This study provides an example of the dynamic rerouting in the transmission of the nociceptive signals following injuries to the peripheral and central processes of sensory neurons. In two rat models for mononeuropathy, the chronic constriction injury model [Bennett, G.J., Xie, Y.K., Pain 33 (1988) 87-107] and the spared nerve injury model [Decosterd, I., Woolf, C.J., Pain 87 (2000) 149-158], we demonstrate that selective dorsal columns lesion produced significant decrease of tactile and cold allodynias and thermal hyperalgesia which were assessed by the Von Frey hair filaments, the acetone drop test and the heat-induced paw withdrawal, respectively. These manifestations, however, can reappear 2 weeks after bilateral dorsal column lesion in rats subjected to spared nerve injury mononeuropathy and appear also in animals sustaining chronic bilateral dorsal column lesion followed by either model of mononeuropathy. Lesion of the dorsal column on the side opposite to the neuropathic leg did not alter the neuropathic manifestations in both animal models. Changes in the sequence of timing of the dorsal column lesion and induction of mononeuropathy, suggest that the effects of the former last for 1 to 2 weeks. The results of this study show that the dorsal columns are involved in neuropathic manifestations and at the same time are not necessary for their full development and persistence. Furthermore, these results shade doubts on the validity of the concept of segregation of pathways involved in the transmission of neuropathic manifestations. Therefore, principles governing acute pain transmission are not necessarily applicable to chronic pain situations. The latter conditions seem to engage other available pathways to reestablish the pain signaling system.

Attenuation of neuropathic pain by segmental and supraspinal activation of the dorsal column system in awake rats.

In addition to its involvement in the transmission of neuropathic pain, the dorsal column system has been shown to have analgesic effects when electrically stimulated. The segmental or supraspinal origin of the analgesia, however, has not been clearly delineated. The aim of this study is to demonstrate the contribution of supraspinal mechanisms to the inhibition of allodynia and hyperalgesia in two different rat models of mononeuropathy. Mononeuropathy was induced, under deep anesthesia, in several groups of rats (n=7 each) following either the chronic constriction injury or the spared nerve injury model. Mechanical and cold allodynia were assessed by the Von Frey monofilaments and by the acetone drop test, respectively. Thermal hyperalgesia was assessed by the paw withdrawal and hot plate tests. Bipolar electrodes for dorsal column stimulation were implanted chronically in all rats on the dorsal aspect of the medulla at the level of the obex. Selective dorsal column bilateral lesions were performed at the upper cervical level in some groups of rats. Dorsal column nuclear stimulation, rostral to selective dorsal spinal lesions, produced strong inhibitory effects on the allodynia and hyperalgesia observed in both models of mononeuropathy. These effects were comparable to those observed following similar stimulations in rats with an intact spinal cord. Our results demonstrate strong inhibitory effects of dorsal column stimulation on neuropathic pain. This inhibition can be attributed to the activation of brainstem pain-modulating centers via rostral projections of the dorsal column nuclei.

Diagnostic accuracy of sonography and combined sonographic assessment and sonographically guided cytology in nonpalpable solid breast lesions.

PURPOSE: The aim of this study was to assess the diagnostic accuracy of sonography alone and combined sonographic assessment and sonographically guided fine-needle aspiration cytology in solid, nonpalpable lesions of the breast. METHODS: We retrospectively evaluated the sonograms from a series of 174 consecutive nonpalpable masses that were cytologically diagnosed using fine-needle aspiration under sonographic guidance and then histologically verified through surgical excision. We examined the relationships between the findings from sonography, combined sonographic assessment and cytopathology, and histology. RESULTS: Histologically, 95 lesions (55%) were malignant and 79 (45%) were benign. The overall sensitivity of sonography alone for diagnosing cancer was 98. 9% (94 of 95 lesions), and the specificity was 45.6% (36 of 79 lesions). One (3%) of 37 masses considered at sonography to be benign was correctly diagnosed on cytologic examination to be cancer. By establishing the benign status of 11 of 13 masses that were indeterminate at sonography, cytology increased the specificity of the combined method (to 56.3%). Cytology appropriately suspected or confirmed malignancy in 79 (84%) of 94 carcinomas considered at sonography to be suspicious or malignant. CONCLUSIONS: In this study, sonography alone demonstrated a high sensitivity but limited specificity in evaluating nonpalpable breast masses. The addition of sonographically guided cytology substantially increased the specificity of the combined method without compromising sensitivity.