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2.
Br J Surg ; 106(11): 1530-1541, 2019 10.
Article de Anglais | MEDLINE | ID: mdl-31436325

RÉSUMÉ

BACKGROUND: Tailored neoadjuvant treatment of locally advanced rectal cancer (LARC) may improve outcomes. The aim of this study was to determine early MRI prognostic parameters with which to stratify neoadjuvant treatment in patients with LARC. METHODS: All patients from a prospective, phase II, multicentre randomized study (GRECCAR4; NCT01333709) were included, and underwent rectal MRI before treatment, 4 weeks after induction chemotherapy and after completion of chemoradiotherapy (CRT). Tumour volumetry, MRI tumour regression grade (mrTRG), T and N categories, circumferential resection margin (CRM) status and extramural vascular invasion identified by MRI (mrEMVI) were evaluated. RESULTS: A total of 133 randomized patients were analysed. Median follow-up was 41·4 (95 per cent c.i. 36·6 to 45·2) months. Thirty-one patients (23·3 per cent) developed tumour recurrence. In univariable analysis, mrEMVI at baseline was the only prognostic factor associated with poorer outcome (P = 0·015). After induction chemotherapy, a larger tumour volume on MRI (P = 0·019), tumour volume regression of 60 per cent or less (P = 0·002), involvement of the CRM (P = 0·037), mrEMVI (P = 0·026) and a poor mrTRG (P = 0·023) were associated with poor outcome. After completion of CRT, the absence of complete response on MRI (P = 0·004), mrEMVI (P = 0·038) and a poor mrTRG (P = 0·005) were associated with shorter disease-free survival. A final multivariable model including all significant variables (baseline, after induction, after CRT) revealed that Eastern Cooperative Oncology Group performance status (P = 0·011), sphincter involvement (P = 0·009), mrEMVI at baseline (P = 0·002) and early tumour volume regression of 60 per cent or less after induction (P = 0·007) were associated with relapse. CONCLUSION: Baseline and early post-treatment MRI parameters are associated with prognosis in LARC. Future preoperative treatment should stratify treatment according to baseline mrEMVI status and early tumour volume regression.


ANTECEDENTES: El tratamiento neoadyuvante personalizado del cáncer de recto localmente avanzado (locally advanced rectal cancer, LARC) puede mejorar los resultados. El objetivo de este estudio fue determinar factores pronósticos precoces mediante RMN para estratificar el tratamiento neoadyuvante en pacientes con LARC. MÉTODOS: Todos los pacientes de un eensayo prospectivo de fase II, multicéntrico y aleatorizado (GRECCAR4-NCT01333709) se incluyeron en este estudio y se les realizó una RMN antes del tratamiento, 4 semanas después de la quimioterapia de inducción y después de completar la quimiorradioterapia (chemoradiation, CRT). Se evaluó la volumetría tumoral, el grado de regresión tumoral mediante RMN (MRI Tumor Regression Grade, mrTRG), la estadificación T, la estadificación N, el estado del margen de resección circunferencial (circumferential resection margin, CRM) y la presencia de invasión extramural vascular en la RMN (extramural vascular invasion, mrEMVI). RESULTADOS: Se analizaron 133 pacientes aleatorizados. La mediana de seguimiento fue de 41,4 meses (i.c. del 95%: 36,6-45,2). En 31 pacientes (23%) se diagnosticó una recidiva. En el análisis univariado de la situación basal, mrEMVI fue el único factor pronóstico asociado con un peor resultado (P = 0,0152). Después de la quimioterapia de inducción, un volumen tumoral más alto en la RMN (P = 0,019), una regresión del volumen tumoral ≤ 60% (P = 0,002), la afectación del CRM (P = 0,037), mrEMVI (P = 0,026) y un grado escaso mrTRG (P = 0,023) se asociaron con un mal resultado. Después de completar la CRT, la ausencia de respuesta completa en la RMN (P = 0,004), la presencia de mrEMVI (P = 0,04) y una insuficiente mrTRG (P = 0,005) se asociaron con una supervivencia libre de enfermedad más corta. En el modelo multivariable final en el que se incluyeron todas las variables significativas (basales, postinducción, post-CRT), el estado de ECOG (P = 0,011), la afectación esfinteriana (P = 0,009), la presencia de EMVI al inicio (P = 0,002) y una regresión precoz del volumen tumoral ≤ 60% después de la inducción (P = 0,007) se asociaron con una recidiva. CONCLUSIÓN: Los parámetros basales y post-tratamiento precoces de la RMN se asocian con el pronóstico en el LARC. La estrategia terapéutica preoperatoria futura deberá estratificar el tratamiento de acuerdo con la presencia de EMVI al inicio y la regresión precoz del volumen tumoral.


Sujet(s)
Protocoles de polychimiothérapie antinéoplasique/administration et posologie , Tumeurs du rectum/mortalité , Adolescent , Adulte , Sujet âgé , Chimioradiothérapie adjuvante/méthodes , Survie sans rechute , Calendrier d'administration des médicaments , Fluorouracil/administration et posologie , Humains , Perfusions veineuses , Irinotécan/administration et posologie , Laparoscopie/statistiques et données numériques , Leucovorine/administration et posologie , Imagerie par résonance magnétique , Adulte d'âge moyen , Récidive tumorale locale , Oxaliplatine/administration et posologie , Médecine de précision/méthodes , Études prospectives , Tumeurs du rectum/anatomopathologie , Tumeurs du rectum/thérapie , Interventions chirurgicales robotisées/statistiques et données numériques , Charge tumorale , Jeune adulte
3.
Heredity (Edinb) ; 122(6): 893-905, 2019 06.
Article de Anglais | MEDLINE | ID: mdl-30542146

RÉSUMÉ

Although low levels of genetic structure are expected in highly widespread species, geographical and/or ecological factors can limit species distributions and promote population structure and morphological differentiation. In order to determine the effects of geographical isolation on population genetic structure and wing morphology, 281 individuals of the cosmopolitan odonate Pantala flavescens were collected from four continental (Central and South America) and five insular sites (Polynesian islands and the Maldives). COI sequences and eight microsatellite loci were used to characterize genetic diversity and genetic structure between and within locations. Linear and geometric morphometry were used to evaluate differences in the size and shape of wings. Genetic analysis showed a global genetic difference between the continental and insular sites. American locations did not show genetic structure, even in locations separated by a distance of 5000 km. Easter Island showed the lowest values of genetic diversity (mainly mitochondrial diversity) and the highest values of genetic differences compared to other insular and continental sites. Individuals from Easter Island showed smaller forewings, a different abdomen length to thorax length ratio, and a different configuration of anal loop in the hindwings. Thus, the greater isolation, smaller area, and young geological age seem to have determined the genetic and morphological differences in P. flavescens of Easter Island, where selection could promote a loss of migratory behavior and may improve other life history traits, such as reproduction. This work provides new insight into how microevolutionary processes operate in isolated populations of cosmopolitan species.


Sujet(s)
Odonata/anatomie et histologie , Odonata/génétique , Animaux , Variation génétique , Génétique des populations , Iles , Répétitions microsatellites , Odonata/croissance et développement , Phylogenèse , Amérique du Sud
4.
Diagn Interv Imaging ; 100(10): 647-655, 2019 Oct.
Article de Anglais | MEDLINE | ID: mdl-30555018

RÉSUMÉ

Tumor heterogeneity in ovarian cancer has been reported at the histological and genetic levels and is associated with adverse clinical outcomes. Tumor evaluation using standard computed tomography or magnetic resonance imaging techniques does not account for the intra- or inter-tumoral heterogeneity in advanced ovarian cancer with peritoneal carcinomatosis. As such, computational approaches in assessing tumor heterogeneity have been proposed using radiomics and radiogenomics in order to analyze the whole tumor heterogeneity as opposed to single biopsy sampling. As part of radiomics, texture analysis, which includes the extraction of multiple data from images has been proposed recently to evaluate advanced ovarian tumor heterogeneity. In this short review, we explain the basics of radiomics, how to perform texture analysis, and its applications to ovarian cancer imaging.


Sujet(s)
Amélioration d'image/méthodes , Tumeurs de l'ovaire/imagerie diagnostique , Femelle , Prédisposition génétique à une maladie , Génomique , Humains , Tumeurs de l'ovaire/génétique
5.
Clin Radiol ; 72(1): 3-10, 2017 Jan.
Article de Anglais | MEDLINE | ID: mdl-27742105

RÉSUMÉ

Tumour heterogeneity in cancers has been observed at the histological and genetic levels, and increased levels of intra-tumour genetic heterogeneity have been reported to be associated with adverse clinical outcomes. This review provides an overview of radiomics, radiogenomics, and habitat imaging, and examines the use of these newly emergent fields in assessing tumour heterogeneity and its implications. It reviews the potential value of radiomics and radiogenomics in assisting in the diagnosis of cancer disease and determining cancer aggressiveness. This review discusses how radiogenomic analysis can be further used to guide treatment therapy for individual tumours by predicting drug response and potential therapy resistance and examines its role in developing radiomics as biomarkers of oncological outcomes. Lastly, it provides an overview of the obstacles in these emergent fields today including reproducibility, need for validation, imaging analysis standardisation, data sharing and clinical translatability and offers potential solutions to these challenges towards the realisation of precision oncology.


Sujet(s)
Interaction entre gènes et environnement , Dépistage génétique/méthodes , Amélioration d'image/méthodes , Tumeurs/imagerie diagnostique , Tumeurs/génétique , Médecine de précision/méthodes , Marqueurs biologiques tumoraux/génétique , Dépistage précoce du cancer/méthodes , Prédisposition génétique à une maladie/génétique , Génomique/méthodes , Humains , Imagerie moléculaire/méthodes
6.
Gynecol Oncol ; 140(3): 420-4, 2016 Mar.
Article de Anglais | MEDLINE | ID: mdl-26790773

RÉSUMÉ

OBJECTIVES: To evaluate the changes in prognostic impression and patient management following PET/CT in patients with vulvar and vaginal carcinoma; and to compare PET/CT findings with those of conventional imaging modalities. METHODS: We summarized prospectively and retrospectively collected data for 50 consecutive patients from our institution that enrolled in the National Oncologic PET Registry and underwent FDG-PET/CT for a suspected or known primary or recurrent vulvar/vaginal cancer. RESULTS: 54/83 (65%) studies included had a diagnosis of vulvar cancer, and the remaining 29/83 (35%), a diagnosis of vaginal cancer. Following FDG-PET/CT, the physician's prognostic impression changed in 51% of cases. A change in patient management, defined as a change to/from a non-interventional strategy (observation or additional imaging), to/from an interventional strategy (biopsy or treatment), was documented in 36% of studies. The electronic records demonstrated that 95% of the management strategies recorded in the physician questionnaires were implemented as planned. MRI and/or CT were performed within one month of the FDG-PET/CT in 20/83 (24%) and 28/83 (34%) cases, respectively. FDG-PET/CT detected nodes suspicious for metastases on 29/83 (35%) studies performed. MRI and CT detected positive nodes on 6 and 11 studies respectively. Distant metastases were identified in 10 cases imaged with FDG-PET and 5 cases that had additional conventional CT imaging. All suspicious lesions seen on CT were positively identified on PET/CT. In 4 cases, an abnormality identified on PET/CT, was not seen on diagnostic CT. CONCLUSIONS: FDG-PET/CT may play an important role in the management of vulvar and vaginal carcinoma.


Sujet(s)
Carcinomes/diagnostic , Tomographie par émission de positons , Tomodensitométrie , Tumeurs du vagin/diagnostic , Tumeurs de la vulve/diagnostic , Carcinomes/secondaire , Carcinomes/thérapie , Prise en charge de la maladie , Femelle , Fluorodésoxyglucose F18 , Humains , Métastase lymphatique , Imagerie multimodale , Pronostic , Études prospectives , Radiopharmaceutiques , Études rétrospectives , Tumeurs du vagin/thérapie , Tumeurs de la vulve/thérapie
7.
Eur Radiol ; 26(6): 1606-12, 2016 Jun.
Article de Anglais | MEDLINE | ID: mdl-26396111

RÉSUMÉ

OBJECTIVES: To evaluate the recommendations for multiparametric prostate MRI (mp-MRI) interpretation introduced in the recently updated Prostate Imaging Reporting and Data System version 2 (PI-RADSv2), and investigate the impact of pathologic tumour volume on prostate cancer (PCa) detectability on mpMRI. METHODS: This was an institutional review board (IRB)-approved, retrospective study of 150 PCa patients who underwent mp-MRI before prostatectomy; 169 tumours ≥0.5-mL (any Gleason Score [GS]) and 37 tumours <0.5-mL (GS ≥4+3) identified on whole-mount pathology maps were located on mp-MRI consisting of T2-weighted imaging (T2WI), diffusion-weighted (DW)-MRI, and dynamic contrast-enhanced (DCE)-MRI. Corresponding PI-RADSv2 scores were assigned on each sequence and combined as recommended by PI-RADSv2. We calculated the proportion of PCa foci on whole-mount pathology correctly identified with PI-RADSv2 (dichotomized scores 1-3 vs. 4-5), stratified by pathologic tumour volume. RESULTS: PI-RADSv2 allowed correct identification of 118/125 (94 %; 95 %CI: 90-99 %) peripheral zone (PZ) and 42/44 (95 %; 95 %CI: 89-100 %) transition zone (TZ) tumours ≥0.5 mL, but only 7/27 (26 %; 95 %CI: 10-42 %) PZ and 2/10 (20 %; 95 %CI: 0-52 %) TZ tumours with a GS ≥4+3, but <0.5 mL. DCE-MRI aided detection of 4/125 PZ tumours ≥0.5 mL and 0/27 PZ tumours <0.5 mL. CONCLUSIONS: PI-RADSv2 correctly identified 94-95 % of PCa foci ≥0.5 mL, but was limited for the assessment of GS ≥4+3 tumours ≤0.5 mL. DCE-MRI offered limited added value to T2WI+DW-MRI. KEY POINTS: • PI-RADSv2 correctly identified 95 % of PCa foci ≥0.5 mL • PI-RADSv2 was limited for the assessment of GS ≥4+3 tumours ≤0.5 mL • DCE-MRI offered limited added value to T2WI+DW-MRI.


Sujet(s)
Imagerie par résonance magnétique/méthodes , Tumeurs de la prostate/imagerie diagnostique , Tumeurs de la prostate/anatomopathologie , Systèmes d'information de radiologie , Sujet âgé , Humains , Mâle , Guides de bonnes pratiques cliniques comme sujet , Prostate/imagerie diagnostique , Prostate/anatomopathologie , Études rétrospectives
8.
Neotrop Entomol ; 44(4): 357-64, 2015 Aug.
Article de Anglais | MEDLINE | ID: mdl-26174961

RÉSUMÉ

Macaria mirthae Vargas et al (Lepidoptera: Geometridae) is a geometrid moth native to the northern Atacama Desert of Chile. Its oligophagous larvae are associated with native hosts of the plant family Fabaceae, the most important of which is Acacia macracantha. The invasive tree Leucaena leucocephala (Fabaceae) was recently recorded as a host plant for M. mirthae based on morphology. The taxonomic status of larvae collected on A. macracantha and L. leucocephala was assessed using sequences of the DNA barcode fragment of the cytochrome c oxidase subunit I (COI) gene. Genetic divergence between samples from the host plants was found to be 0%-0.8% (Kimura 2-parameter model). Neighbor-joining and maximum likelihood analyses were also performed, including additional barcode sequences of Neotropical geometrid moths from GenBank and BOLD databases. Sequences of the larvae from both host plants clustered in a single clade with high statistical support in both analyses. Based on these results, it is concluded that M. mirthae has effectively expanded its host range and its larvae are currently feeding on the exotic tree L. leucocephala. Additionally, the importance of this new host association in a highly disturbed habitat is briefly discussed in terms of the field biology of this native geometrid moth.


Sujet(s)
Fabaceae/parasitologie , Papillons de nuit/classification , Papillons de nuit/génétique , Animaux , Chili , Codage à barres de l'ADN pour la taxonomie , Climat désertique
9.
Eur Radiol ; 25(11): 3348-53, 2015 Nov.
Article de Anglais | MEDLINE | ID: mdl-25916387

RÉSUMÉ

OBJECTIVE: Our aim was to evaluate the associations between quantitative (18)F-fluorodeoxyglucose positron-emission tomography (FDG-PET) uptake metrics, optimal debulking (OD) and progression-free survival (PFS) in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery. METHODS: Fifty-five patients with recurrent ovarian cancer underwent FDG-PET/CT within 90 days prior to surgery. Standardized uptake values (SUVmax), metabolically active tumour volumes (MTV), and total lesion glycolysis (TLG) were measured on PET. Exact logistic regression, Kaplan-Meier curves and the log-rank test were used to assess associations between imaging metrics, OD and PFS. RESULTS: MTV (p = 0.0025) and TLG (p = 0.0043) were associated with OD; however, there was no significant association between SUVmax and debulking status (p = 0.83). Patients with an MTV above 7.52 mL and/or a TLG above 35.94 g had significantly shorter PFS (p = 0.0191 for MTV and p = 0.0069 for TLG). SUVmax was not significantly related to PFS (p = 0.10). PFS estimates at 3.5 years after surgery were 0.42 for patients with an MTV ≤ 7.52 mL and 0.19 for patients with an MTV > 7.52 mL; 0.46 for patients with a TLG ≤ 35.94 g and 0.15 for patients with a TLG > 35.94 g. CONCLUSION: FDG-PET metrics that reflect metabolic tumour burden are associated with optimal secondary cytoreductive surgery and progression-free survival in patients with recurrent ovarian cancer. KEY POINTS: • Both TLG and MTV were associated with optimal tumour debulking. • There was no significant association between SUVmax and tumour debulking status. • Patients with higher MTV and/or TLG had significantly shorter PFS. • SUVmax was not significantly related to PFS.


Sujet(s)
Fluorodésoxyglucose F18 , Tumeurs épithéliales épidermoïdes et glandulaires/chirurgie , Tumeurs de l'ovaire/chirurgie , Radiopharmaceutiques , Sujet âgé , Sujet âgé de 80 ans ou plus , Carcinome épithélial de l'ovaire , Tomodensitométrie à faisceau conique , Interventions chirurgicales de cytoréduction/méthodes , Survie sans rechute , Femelle , Glycolyse/physiologie , Humains , Adulte d'âge moyen , Imagerie multimodale/méthodes , Récidive tumorale locale , Tumeurs épithéliales épidermoïdes et glandulaires/anatomopathologie , Tumeurs de l'ovaire/anatomopathologie , Tomographie par émission de positons/méthodes , Pronostic , Études rétrospectives , Tomodensitométrie/méthodes , Charge tumorale
10.
Rofo ; 184(10): 967-74, 2013 Sep.
Article de Anglais | MEDLINE | ID: mdl-23999785

RÉSUMÉ

PURPOSE: To evaluate the role of conventional endorectal prostate MRI in patients with initial suspicion of prostate cancer. MATERIALS AND METHODS: Ethics board approval was received for this retrospective study of 87 men who underwent 1.5-Tesla conventional prostate MRI with a combination of endorectal and body phased-array coils for suspected prostate cancer before their first systematic 12-core TRUS-guided biopsy. Three radiologists independently analyzed the images, dividing the prostate into 12 regions corresponding to the biopsy scheme and scoring each region for the presence of prostate cancer on a 5-point scale. Results were analyzed by prostate region. ROC analysis was done and descriptive statistics were calculated. The negative predictive value, specificity, sensitivity and positive predictive value were calculated using dichotomized scores (benign tissue = scores of 1 and 2; malignant tissues = scores of 3, 4, and 5). RESULTS: Biopsy revealed cancer in 47/87 patients (26 low-grade [Gleason score 6]; 21 high-grade [Gleason score ≥ 3 + 4]), and 184/1044 cores (77 low-grade and 107 high-grade) with a median of 3 positive cores per cancer patient (range 1 - 12). The areas under ROC curves were 0.65 - 0.67 for cancer detection by region overall and 0.75 - 0.76 for the detection of high-grade cancer by region. Statistic figures for the detection of all cancers/high-grade cancers by region were as follows: negative predictive value, 87.4 - 88.2 %/92.6 - 93.1 %; specificity, 72.3 - 79.4 %/71.5 - 79.8 %; sensitivity, 49.5 - 54.8 %/62.6 - 69.2 %; and positive predictive value, 29.3 - 34.0 %/29.4 - 34.7 %. CONCLUSION: In patients with suspected prostate cancer, negative MRI findings indicate the absence of high-grade prostate cancer on subsequent TRUS-guided 12-core biopsy with high probability. However, agreement between conventional 1.5-T endorectal prostate MRI and systematic 12-core TRUS-guided biopsy for the detection of prostate cancer appears to be moderate.


Sujet(s)
Interprétation d'images assistée par ordinateur/méthodes , Biopsie guidée par l'image/méthodes , Imagerie interventionnelle par résonance magnétique/méthodes , Tumeurs de la prostate/diagnostic , Tumeurs de la prostate/anatomopathologie , Sujet âgé , Humains , Noeuds lymphatiques/anatomopathologie , Mâle , Adulte d'âge moyen , Grading des tumeurs , Prostate/anatomopathologie , Études rétrospectives , Sensibilité et spécificité , Imagerie du corps entier/méthodes
11.
Neotrop Entomol ; 42(1): 112-4, 2013 Feb.
Article de Anglais | MEDLINE | ID: mdl-23949720

RÉSUMÉ

Acrocercops Wallengren (Gracillariidae) is recorded for the first time from Chile. The little known Acrocercops serrigera serrigera Meyrick is reported from the Azapa Valley, Arica Province, northern Chilean coastal desert. Specimens were reared from Malva nicaeensis and Waltheria ovata (both Malvaceae). Specimen identification is based on comparisons of the male genitalia with that of the lectotype of the species originated from Peru. Sequences of a fragment of the mitochondrial gene cytochrome oxidase subunit I of specimens reared on both plants indicate that there is only one Acrocercops species involved as only one substitution site was found over the 524-bp sequenced.


Sujet(s)
Lepidoptera , Répartition des animaux , Animaux , Chili , Femelle , Mâle
12.
Abdom Imaging ; 38(6): 1431-46, 2013 Dec.
Article de Anglais | MEDLINE | ID: mdl-23604966

RÉSUMÉ

In patients with a clinical suspicion of recurrence after treatment for prostate cancer, imaging can be used to distinguish between local recurrence and metastatic disease. Multiparametric magnetic resonance imaging (mpMRI) of the prostate may be a valuable imaging modality for the detection and localization of local recurrence in patients treated for prostate cancer. In mpMRI, morphological T2-weighted images are combined with functional MRI techniques including diffusion-weighted imaging, dynamic contrast-enhanced imaging, and magnetic resonance spectroscopic imaging to improve accuracy. In this paper, the current status of imaging techniques used to detect and to localize tumor recurrence in patients treated for prostate cancer will be reviewed, with emphasis on mpMRI for local prostate cancer recurrence.


Sujet(s)
Imagerie par résonance magnétique/méthodes , Récidive tumorale locale/diagnostic , Tumeurs de la prostate/diagnostic , Traitement médicamenteux adjuvant , Association thérapeutique , Produits de contraste , Humains , Mâle , Métastase tumorale , Récidive tumorale locale/anatomopathologie , Récidive tumorale locale/chirurgie , Complications postopératoires/diagnostic , Prostatectomie , Tumeurs de la prostate/anatomopathologie , Tumeurs de la prostate/chirurgie , Radiothérapie adjuvante , Sensibilité et spécificité
13.
Neotrop Entomol ; 42(6): 595-9, 2013 Dec.
Article de Anglais | MEDLINE | ID: mdl-27193277

RÉSUMÉ

Phenological studies are especially important in order to understand the ecological process operating at temporal level. The western slopes of the northern Chilean Andes at about 3,500 m asl are a mosaic of arid environments in which precipitations are highly seasonal, mostly concentrated in summer. Teriocolias zelia andina Forbes (Lepidoptera: Pieridae) is one of the most conspicuous and regularly observed butterflies flying in this region; it is a host specialist associated with the native shrub Senna birostris var. arequipensis (Fabaceae). The objectives of this study were (1) to characterize the temporal variations in the relative abundance of eggs of this host-specialist butterfly and (2) to examine the relationship of these variations with leaf phenology. Monthly samplings of eggs were carried out from February 2011 to January 2012. Circular statistical analyses of the relative abundance of eggs indicated clustered distribution along the year with the mean vector in June. Temporal variation in the relative abundance of eggs was correlated (Spearman rank correlation test) with the availability of plant substrate for egg laying and larval feeding.


Sujet(s)
Papillons , Oviposition , Animaux , Chili , Environnement , Larve , Dynamique des populations
14.
Rofo ; 185(10): 967-74, 2013 Oct.
Article de Anglais | MEDLINE | ID: mdl-24490232

RÉSUMÉ

PURPOSE: To evaluate the role of conventional endorectal prostate MRI in patients with initial suspicion of prostate cancer. MATERIALS AND METHODS: Ethics board approval was received for this retrospective study of 87 men who underwent 1.5-Tesla conventional prostate MRI with a combination of endorectal and body phased-array coils for suspected prostate cancer before their first systematic 12-core TRUS-guided biopsy. Three radiologists independently analyzed the images, dividing the prostate into 12 regions corresponding to the biopsy scheme and scoring each region for the presence of prostate cancer on a 5-point scale. Results were analyzed by prostate region. ROC analysis was done and descriptive statistics were calculated. The negative predictive value, specificity, sensitivity and positive predictive value were calculated using dichotomized scores (benign tissue = scores of 1 and 2; malignant tissues = scores of 3, 4, and 5). RESULTS: Biopsy revealed cancer in 47/87 patients (26 low-grade [Gleason score 6]; 21 high-grade [Gleason score ≥ 3 + 4]), and 184/1044 cores (77 low-grade and 107 high-grade) with a median of 3 positive cores per cancer patient (range 1 ­ 12). The areas under ROC curves were 0.65 ­ 0.67 for cancer detection by region overall and 0.75 ­ 0.76 for the detection of high-grade cancer by region. Statistic figures for the detection of all cancers/high-grade cancers by region were as follows: negative predictive value, 87.4 ­ 88.2 %/92.6 ­ 93.1 %; specificity, 72.3 ­ 79.4 %/71.5 ­ 79.8 %; sensitivity, 49.5 ­ 54.8 %/62.6 ­ 69.2 %; and positive predictive value, 29.3 ­ 34.0 %/29.4 ­ 34.7 %. CONCLUSION: In patients with suspected prostate cancer, negative MRI findings indicate the absence of high-grade prostate cancer on subsequent TRUS-guided 12-core biopsy with high probability. However, agreement between conventional 1.5-T endorectal prostate MRI and systematic 12-core TRUS-guided biopsy for the detection of prostate cancer appears to be moderate.


Sujet(s)
Interprétation d'images assistée par ordinateur/méthodes , Imagerie interventionnelle par résonance magnétique/méthodes , Tumeurs de la prostate/diagnostic , Tumeurs de la prostate/anatomopathologie , Sujet âgé , Marqueurs biologiques tumoraux/sang , Biopsie au trocart , Toucher rectal , Humains , Imagerie tridimensionnelle/méthodes , Imagerie interventionnelle par résonance magnétique/instrumentation , Mâle , Adulte d'âge moyen , Grading des tumeurs , Pronostic , Prostate/anatomopathologie , Antigène spécifique de la prostate/sang , Courbe ROC , Études rétrospectives , Sensibilité et spécificité
15.
Eur J Radiol ; 81(12): 4131-7, 2012 Dec.
Article de Anglais | MEDLINE | ID: mdl-22858427

RÉSUMÉ

PURPOSE: To prospectively evaluate the diagnostic performance of magnetic resonance imaging (MRI), (11)C-acetate positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT for bladder cancer staging, using whole-mount pathologic review of radical cystectomy and pelvic lymph node specimens as the reference standard. MATERIALS AND METHODS: The institutional review board approved this prospective study, which was compliant with the Health Insurance Portability and Accountability Act. Written informed consent was obtained from 16 patients with histologically confirmed bladder cancer who underwent MRI, (11)C-acetate PET/CT and contrast-enhanced CT before radical cystectomy and pelvic lymph node dissection. Before imaging 4/16 patients had received intravesical Bacillus Calmette-Guérin treatment, 6 had received systemic chemotherapy, 3 had received both and 3 had received neither. Measures of diagnostic performance including accuracy, sensitivity and specificity were estimated separately for each imaging modality. RESULTS: MRI correctly staged 56% of patients (9/16), overstaged 38% (6/16) and understaged 6% (1/16). CT correctly staged 50% of patients (8/16), overstaged 44% (7/16) and understaged 6% (1/16). In 9 patients, (11)C-acetate PET/CT showed uptake within the bladder wall; the uptake was true-positive in 7 patients and false-positive in 2 patients. Of the remaining 7 patients, 5 had true-negative and 2 had false-negative PET/CT results for cancer in the bladder wall. For all modalities, staging accuracy was reduced in patients with a history of prior intravesical and/or systemic chemotherapy. CONCLUSION: In staging bladder cancer, MRI, (11)C-acetate PET/CT and CT displayed similar levels of accuracy. For all modalities, a history of intravesical and/or systemic chemotherapy affected staging accuracy.


Sujet(s)
Acétates , Carbone , Iohexol , Imagerie par résonance magnétique/méthodes , Imagerie multimodale/méthodes , Tomographie par émission de positons , Tomodensitométrie , Tumeurs de la vessie urinaire/diagnostic , Adulte , Sujet âgé , Produits de contraste , Femelle , Humains , Mâle , Adulte d'âge moyen , Stadification tumorale/méthodes , Études prospectives , Radiopharmaceutiques , Reproductibilité des résultats , Sensibilité et spécificité
16.
AJNR Am J Neuroradiol ; 33(11): 2178-85, 2012 Dec.
Article de Anglais | MEDLINE | ID: mdl-22555585

RÉSUMÉ

BACKGROUND AND PURPOSE: The role of DCE-MR imaging in the study of bone marrow perfusion is only partially developed, though potential applications for routine use in the clinical setting are beginning to be described. We hypothesize that DCE-MR imaging can be used to discriminate between hypervascular and hypovascular metastases based on measured perfusion variables. MATERIALS AND METHODS: We conducted a retrospective study of 26 patients using conventional MR imaging and DCE-MR imaging. Patients were assigned to a hypervascular or hypovascular group based on tumor pathology. ROIs were drawn around normal-appearing bone marrow (internal controls) and enhancing tumor areas. Average wash-in enhancement slope, average peak enhancement signal percentage change, and average peak enhancement signal percentage change in areas of highest wash-in enhancement slope were calculated. Indices were compared among control, hypervascular, and hypovascular groups. Conventional imaging was assessed by calculating pre- to postgadolinium signal percentage changes in hypervascular and hypovascular lesions. RESULTS: Hypervascular and hypovascular tumors differed significantly with regard to wash-in enhancement slope (P < .01; hypervascular 95% CI, 22.5-26.5 AU/s; hypovascular 95% CI, 14.1-20.9 AU/s) and peak enhancement signal percentage change in areas of highest wash-in enhancement slope (P < .01; hypervascular 95% CI, 174.1-323.3%; hypovascular 95% CI, 39.5-150.5%). Peak enhancement signal percentage change over all voxels was not significant (P = .62). Areas of normal-appearing marrow showed no appreciable contrast enhancement. Conventional contrast-enhanced MR imaging was unable to differentiate between hypervascular and hypovascular tumors (P = .58). CONCLUSIONS: Our data demonstrate that, unlike conventional MR imaging sequences, DCE-MR imaging may be a more accurate technique in discriminating hypervascular from hypovascular spinal metastases.


Sujet(s)
Moelle osseuse/vascularisation , Moelle osseuse/anatomopathologie , Imagerie par résonance magnétique/méthodes , Tumeurs du rachis/anatomopathologie , Tumeurs du rachis/secondaire , Rachis/anatomopathologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Produits de contraste , Femelle , Acide gadopentétique , Humains , Mâle , Adulte d'âge moyen , Néovascularisation pathologique/complications , Néovascularisation pathologique/anatomopathologie , Reproductibilité des résultats , Sensibilité et spécificité , Tumeurs du rachis/vascularisation , Tumeurs du rachis/complications
17.
Neotrop Entomol ; 41(6): 524-5, 2012 Dec.
Article de Anglais | MEDLINE | ID: mdl-23949680

RÉSUMÉ

The shrub Senna birostris var. arequipensis (Fabaceae) is recorded as the first host plant for the little known butterfly Teriocolias zelia andina Forbes (Lepidoptera: Pieridae) in the occidental slopes of the Andes, northernmost Chile. Observations on egg-laying and larva-feeding behavior suggest that this butterfly is host specific.


Sujet(s)
Fabaceae/parasitologie , Lepidoptera/physiologie , Animaux , Chili , Femelle , Mâle
18.
Neotrop Entomol ; 40(1): 85-8, 2011.
Article de Anglais | MEDLINE | ID: mdl-21437487

RÉSUMÉ

Male and female adults of a new species of Alucita L. (Lepidoptera: Alucitidae) are described and illustrated from the Azapa Valley, northern Chile. Immature stages are associated with fruit of "chuve", Tecoma fulva (Cav.) D. Don. (Bignoniaceae). This is the first species of Alucitidae described from Chile.


Sujet(s)
Lepidoptera/classification , Animaux , Chili , Femelle , Lepidoptera/anatomie et histologie , Mâle
19.
Neotrop Entomol ; 40(1): 152-3, 2011.
Article de Anglais | MEDLINE | ID: mdl-21437500

RÉSUMÉ

The presence of Stigmella epicosma (Meyrick) is reported for the first time from two coastal valleys from northern Chile: Azapa and Chaca. Adults examined were reared from leafminer larvae on Trixis cacalioides (Asteraceae), the first host plant known for S. epicosma.


Sujet(s)
Asteraceae/parasitologie , Lepidoptera/physiologie , Animaux , Chili , Démographie
20.
Clin Radiol ; 64(11): 1048-55, 2009 Nov.
Article de Anglais | MEDLINE | ID: mdl-19822237

RÉSUMÉ

The lymphomas are a heterogeneous group of malignancies, which exhibit a range of different molecular features, genetics, and clinical presentations. Consequently, therapeutic approaches and clinical outcomes differ greatly. Following therapy, the thorax may be a site of disease recurrence, but infection, drug reactions, and radiation pneumonitis are commonly encountered. We present a comprehensive review of these conditions, focussing on their radiological appearances, in order that radiologists may better engage their colleagues in haemato-oncology.


Sujet(s)
Transplantation de moelle osseuse/imagerie diagnostique , Tumeurs du poumon/imagerie diagnostique , Lymphomes/imagerie diagnostique , Récidive tumorale locale/imagerie diagnostique , Poumon radique/imagerie diagnostique , Maladies de l'appareil respiratoire/imagerie diagnostique , Adulte , Sujet âgé , Anticorps monoclonaux , Anticorps monoclonaux d'origine murine , Antinéoplasiques/effets indésirables , Transplantation de moelle osseuse/effets indésirables , Femelle , Humains , Tumeurs du poumon/thérapie , Métastase lymphatique , Lymphomes/thérapie , Mâle , Adulte d'âge moyen , Maladies de l'appareil respiratoire/induit chimiquement , Rituximab , Tomodensitométrie , Résultat thérapeutique , Jeune adulte
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