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1.
Ann Surg Oncol ; 2024 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-38797789

RESUMEN

BACKGROUND: For many tumors, radiomics provided a relevant prognostic contribution. This study tested whether the computed tomography (CT)-based textural features of intrahepatic cholangiocarcinoma (ICC) and peritumoral tissue improve the prediction of survival after resection compared with the standard clinical indices. METHODS: All consecutive patients affected by ICC who underwent hepatectomy at six high-volume centers (2009-2019) were considered for the study. The arterial and portal phases of CT performed fewer than 60 days before surgery were analyzed. A manual segmentation of the tumor was performed (Tumor-VOI). A 5-mm volume expansion then was applied to identify the peritumoral tissue (Margin-VOI). RESULTS: The study enrolled 215 patients. After a median follow-up period of 28 months, the overall survival (OS) rate was 57.0%, and the progression-free survival (PFS) rate was 34.9% at 3 years. The clinical predictive model of OS had a C-index of 0.681. The addition of radiomic features led to a progressive improvement of performances (C-index of 0.71, including the portal Tumor-VOI, C-index of 0.752 including the portal Tumor- and Margin-VOI, C-index of 0.764, including all VOIs of the portal and arterial phases). The latter model combined clinical variables (CA19-9 and tumor pattern), tumor indices (density, homogeneity), margin data (kurtosis, compacity, shape), and GLRLM indices. The model had performance equivalent to that of the postoperative clinical model including the pathology data (C-index of 0.765). The same results were observed for PFS. CONCLUSIONS: The radiomics of ICC and peritumoral tissue extracted from preoperative CT improves the prediction of survival. Both the portal and arterial phases should be considered. Radiomic and clinical data are complementary and achieve a preoperative estimation of prognosis equivalent to that achieved in the postoperative setting.

2.
Eur Radiol ; 34(7): 4475-4483, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38127075

RESUMEN

OBJECTIVES: To assess the incidence (1 year) and the cumulative incidence (3 years) of the condition of patients accruing cumulative effective doses (CED) of ≥ 100 mSv and their variability among different hospitals. To establish and validate a reference level for the CED in patients with recurrent exposures (RERL) and provide a RERL value. METHODS: Data of CT exposure was collected in 9 similar hospitals. The database included 294,222 patient*years who underwent 442,278 CT exams in 3 years. The incidence proportion of patients with CED ≥ 100 mSv in a given year (I100;1) and the 3-year cumulative incidence of patients with CED ≥ 100 mSv over 3 consecutive years (I100;3) were calculated and compared among different institutions. RESULTS: I100;1 ranged from a minimum of 0.1% to a maximum of 5.1%. The percentage of recurrent patients was quite uniform among centres ranging from 23 to 38%. The I100;3 ranged from a minimum of 1.1 to 11.4%. There was a strong positive correlation between the third quartile values of yearly CED and yearly incidence (r = 0.90; R2 = 0.81; p < 0.0001). RERL value in our study was found at 34.0 mSv. CONCLUSION: The management of patients with recurrent exposures is highly variable among hospitals leading to a 50-fold variation in I100;1 and to a tenfold variation in I100;3. RERL could be established and used by taking as a RERL quantity the CED and as a RERL value the 75th percentile of the third quartiles of the distribution of the yearly CED obtained by surveying different hospitals. CLINICAL RELEVANCE STATEMENT: This is the first ever multicentre study that quantifies recurrent exposures in terms of incidence and cumulative incidence of patients with CED ≥ 100 mSv. RERL establishment and use could benefit the optimisation of radioprotection of patients with recurrent exposures. KEY POINTS: This is the first multicentre study estimating yearly incidence and 3-year cumulative incidence of patients with cumulative effective doses ≥ 100 mSv. In this study, a 50-fold inter centre variation between the maximum (5.1%) and the minimum value (0.1%) of yearly incidence of patients with cumulative effective doses ≥ 100 mSv was reported. The range of the 3-year cumulative incidence extended from 1.1 to 11.4% (a tenfold variation) The third quartile of the yearly cumulative effective doses in a centre showed a strong positive correlation with the yearly incidence of patients with cumulative effective doses ≥ 100 mSv, with a potential of being used to set reference levels for recurrent exposures.


Asunto(s)
Dosis de Radiación , Tomografía Computarizada por Rayos X , Humanos , Tomografía Computarizada por Rayos X/métodos , Adulto , Incidencia , Femenino , Masculino , Exposición a la Radiación/prevención & control , Valores de Referencia , Protección Radiológica/métodos , Persona de Mediana Edad , Recurrencia
3.
Gut ; 66(8): 1434-1440, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-27196588

RESUMEN

IMPORTANCE AND AIMS: The role of CT colonography (CTC) as a colorectal cancer (CRC) screening test is uncertain. The aim of our trial was to compare participation and detection rate (DR) with sigmoidoscopy (flexible sigmoidoscopy (FS)) and CTC in a screening setting. DESIGN SETTING AND PARTICIPANTS: We conducted two randomised clinical trials (RCTs). (1) Participation RCT: individuals, aged 58 years, living in Turin (Italy), were randomly assigned to be invited to FS or CTC screening; (2) detection RCT: residents in northern Italy, aged 58-60, giving their consent to recruitment, were randomly allocated to CTC or FS. Polyps ≥6 mm at CTC, or 'high-risk' distal lesions at FS, were referred for colonoscopy (TC). MAIN OUTCOME MEASURES: Participation rate (proportion of invitees examined); DR of advanced adenomas or CRC (advanced neoplasia (AN)). RESULTS: Participation was 30.4% (298/980) for CTC and 27.4% (267/976) for FS (relative risk (RR) 1.1; 95% CI 0.98 to 1.29). Among men, participation was higher with CTC than with FS (34.1% vs 26.5%, p=0.011). In the detection RCT, 2673 subjects had FS and 2595 had CTC: the AN DR was 4.8% (127/2673, including 9 CRCs) with FS and 5.1% (133/2595, including 10 CRCs) with CTC (RR 1.08; 95% CI 0.85 to 1.37). Distal AN DR was 3.9% (109/2673) with FS and 2.9% (76/2595) with CTC (RR 0.72; 95% CI 0.54 to 0.96); proximal AN DR was 1.2% (34/2595) for FS vs 2.7% (69/2595) for CTC (RR 2.06; 95% CI 1.37 to 3.10). CONCLUSIONS AND RELEVANCE: Participation and DR for FS and CTC were comparable. AN DR was twice as high in the proximal colon and lower in the distal colon with CTC than with FS. Men were more likely to participate in CTC screening. TRIAL REGISTRATION NUMBER: NCT01739608; Pre-results.


Asunto(s)
Adenoma/diagnóstico por imagen , Pólipos del Colon/diagnóstico por imagen , Colonografía Tomográfica Computarizada , Neoplasias Colorrectales/diagnóstico por imagen , Detección Precoz del Cáncer/métodos , Sigmoidoscopía , Adenoma/patología , Neoplasias Colorrectales/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud/estadística & datos numéricos , Factores Sexuales
4.
Radiol Med ; 122(8): 623-632, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28421406

RESUMEN

AIM: Our study aimed to investigate the role of qualitative and quantitative whole body MRI with DWI for assessment of bone marrow involvement (BMI) in newly diagnosed lymphoma using FDG PET-CT and bone marrow biopsy (BMB) as reference standard. MATERIALS AND METHODS: We retrospectively evaluated 56 patients with newly diagnosed lymphoma (21 Hodgkin's lymphoma and 35 non-Hodgkin's lymphoma) who underwent random unilateral BMB, FDG PET-CT and Wb-MRI-DWI for initial staging. In a patient-based analysis, results of Wb-MRI-DWI were compared with FDG PET-CT and BMB. For quantitative analysis, mean ADC values of posterior iliac crest were correlated with BMI and bone marrow cellularity. RESULTS: WB-MR-DWI obtained excellent concordance with FDG PET-CT both in HL (k = 1.000; 95% CI 1.000-1.000) and in DLBCL (k = 1.000; 95% CI 1.000-1.000). In other NHL, WB-MRI-DWI obtained a good correlation with BMB (k = 0.611; 95% CI 0.295-0.927) while FDG PET-CT had poor concordance (k = 0.067; 95% CI 0.372-0.505). WB-MR-DWI has no false negative errors but 4 false positive results consisting in focal lesions consensually reported by FDG PET-CT and resolved after therapy. No significant correlation between ADC mean value and BMI was found (p = 0.0586). CONCLUSION: Our data suggest that Wb-MRI-DWI is a valid technique for BMI assessment in lymphoma patients, thanks to its excellent concordance with FDG PET-CT and good concordance with BMB (superior than FDG PET-CT). If further investigations will confirm our results on larger patient groups, it could become a useful tool in the clinical workup.


Asunto(s)
Médula Ósea/diagnóstico por imagen , Médula Ósea/patología , Imagen de Difusión por Resonancia Magnética/métodos , Linfoma/diagnóstico por imagen , Linfoma/patología , Tomografía Computarizada por Tomografía de Emisión de Positrones , Imagen de Cuerpo Entero , Adolescente , Adulto , Anciano , Biopsia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Retrospectivos
5.
Eur Radiol ; 23(3): 739-47, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22976920

RESUMEN

OBJECTIVES: To compare the diagnostic accuracy and sensitivity of Gd-EOB-DTPA MRI and diffusion-weighted (DWI) imaging alone and in combination for detecting colorectal liver metastases in patients who had undergone preoperative chemotherapy. METHODS: Thirty-two consecutive patients with a total of 166 liver lesions were retrospectively enrolled. Of the lesions, 144 (86.8 %) were metastatic at pathology. Three image sets (1, Gd-EOB-DTPA; 2, DWI; 3, combined Gd-EOB-DTPA and DWI) were independently reviewed by two observers. Statistical analysis was performed on a per-lesion basis. RESULTS: Evaluation of image set 1 correctly identified 127/166 lesions (accuracy 76.5 %; 95 % CI 69.3-82.7) and 106/144 metastases (sensitivity 73.6 %, 95 % CI 65.6-80.6). Evaluation of image set 2 correctly identified 108/166 (accuracy 65.1 %, 95 % CI 57.3-72.3) and 87/144 metastases (sensitivity of 60.4 %, 95 % CI 51.9-68.5). Evaluation of image set 3 correctly identified 148/166 (accuracy 89.2 %, 95 % CI 83.4-93.4) and 131/144 metastases (sensitivity 91 %, 95 % CI 85.1-95.1). Differences were statistically significant (P < 0.001). Notably, similar results were obtained analysing only small lesions (<1 cm). CONCLUSIONS: The combination of DWI with Gd-EOB-DTPA-enhanced MRI imaging significantly increases the diagnostic accuracy and sensitivity in patients with colorectal liver metastases treated with preoperative chemotherapy, and it is particularly effective in the detection of small lesions.


Asunto(s)
Carcinoma/patología , Carcinoma/secundario , Neoplasias Colorrectales/patología , Gadolinio DTPA , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/secundario , Imagen por Resonancia Magnética/métodos , Anciano , Antineoplásicos/uso terapéutico , Carcinoma/tratamiento farmacológico , Neoplasias Colorrectales/tratamiento farmacológico , Medios de Contraste , Quimioterapia , Femenino , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Cuidados Preoperatorios , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
6.
Cancers (Basel) ; 15(17)2023 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-37686480

RESUMEN

Standard imaging cannot assess the pathology details of intrahepatic cholangiocarcinoma (ICC). We investigated whether CT-based radiomics may improve the prediction of tumor characteristics. All consecutive patients undergoing liver resection for ICC (2009-2019) in six high-volume centers were evaluated for inclusion. On the preoperative CT, we segmented the ICC (Tumor-VOI, i.e., volume-of-interest) and a 5-mm parenchyma rim around the tumor (Margin-VOI). We considered two types of pathology data: tumor grading (G) and microvascular invasion (MVI). The predictive models were internally validated. Overall, 244 patients were analyzed: 82 (34%) had G3 tumors and 139 (57%) had MVI. For G3 prediction, the clinical model had an AUC = 0.69 and an Accuracy = 0.68 at internal cross-validation. The addition of radiomic features extracted from the portal phase of CT improved the model performance (Clinical data+Tumor-VOI: AUC = 0.73/Accuracy = 0.72; +Tumor-/Margin-VOI: AUC = 0.77/Accuracy = 0.77). Also for MVI prediction, the addition of portal phase radiomics improved the model performance (Clinical data: AUC = 0.75/Accuracy = 0.70; +Tumor-VOI: AUC = 0.82/Accuracy = 0.73; +Tumor-/Margin-VOI: AUC = 0.82/Accuracy = 0.75). The permutation tests confirmed that a combined clinical-radiomic model outperforms a purely clinical one (p < 0.05). The addition of the textural features extracted from the arterial phase had no impact. In conclusion, the radiomic features of the tumor and peritumoral tissue extracted from the portal phase of preoperative CT improve the prediction of ICC grading and MVI.

7.
Eur Radiol ; 19(3): 761-9, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18825386

RESUMEN

To evaluate diagnostic performance of endorectal magnetic resonance (eMR) for diagnosing local recurrence of prostate cancer (PC) in patients with previous radical prostatectomy (RP) and to assess whether contrast-enhanced (CE)-eMR improved diagnostic accuracy in comparison to unenhanced study. Unenhanced eMR data of 72 male patients (mean of total PSA: 1.23 +/- 1.3 ng/ml) with previous RP were interpreted retrospectively and classified either as normal or suspicious for local recurrence. All eMR examinations were re-evaluated also on CE-eMR 4 months after the first reading. Images were acquired on a 1.5-T system. These data were compared to the standard of reference for local recurrence: prostatectomy bed biopsy results; choline positron emission tomography results; PSA reduction or increase after pelvic radiotherapy; PSA modification during active surveillance. Sensitivity, specificity, predictive positive value, negative predictive value and accuracy were 61.4%, 82.1%, 84.4%, 57.5% and 69.4% for unenhanced eMR and 84.1%, 89.3%, 92.5%, 78.1% and 86.1% for CE-eMR. A statistically significant difference was found between accuracy and sensitivity of the two evaluations (chi(2) = 5.33; p = 0.02 and chi(2) = 9.00; p = 0.0027). EMR had great accuracy for visualizing local recurrence of PC after RP. CE-eMR improved diagnostic performance in comparison with T2-weighted imaging alone.


Asunto(s)
Medios de Contraste/farmacología , Imagen por Resonancia Magnética/métodos , Prostatectomía/métodos , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/cirugía , Anciano , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Próstata/patología , Antígeno Prostático Específico/biosíntesis , Recurrencia , Valores de Referencia , Reproducibilidad de los Resultados , Estudios Retrospectivos
8.
JAMA ; 301(23): 2453-61, 2009 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-19531785

RESUMEN

CONTEXT: Computed tomographic (CT) colonography has been recognized as an alternative for colorectal cancer (CRC) screening in average-risk individuals, but less information is available on its performance in individuals at increased risk of CRC. OBJECTIVE: To assess the accuracy of CT colonography in detecting advanced colorectal neoplasia in asymptomatic individuals at increased risk of CRC using unblinded colonoscopy as the reference standard. DESIGN, SETTING, AND PARTICIPANTS: This was a multicenter, cross-sectional study. Individuals at increased risk of CRC due to either family history of advanced neoplasia in first-degree relatives, personal history of colorectal adenomas, or positive results from fecal occult blood tests (FOBTs) were recruited in 11 Italian centers and 1 Belgian center between December 2004 and May 2007. Each participant underwent CT colonography followed by colonoscopy on the same day. MAIN OUTCOME MEASURES: Sensitivity and specificity of CT colonography in detecting individuals with advanced neoplasia (ie, advanced adenoma or CRC) 6 mm or larger. RESULTS: Of 1103 participants, 937 were included in the final analysis: 373 cases in the family-history group, 343 in the group with personal history of adenomas, and 221 in the FOBT-positive group. Overall, CT colonography identified 151 of 177 participants with advanced neoplasia 6 mm or larger (sensitivity, 85.3%; 95% confidence interval [CI], 79.0%-90.0%) and correctly classified results as negative for 667 of 760 participants without such lesions (specificity, 87.8%; 95% CI, 85.2%-90.0%). The positive and negative predictive values were 61.9% (95% CI, 55.4%-68.0%) and 96.3% (95% CI, 94.6%-97.5%), respectively; after group stratification, a significantly lower negative predictive value was found for the FOBT-positive group (84.9%; 95% CI, 76.2%-91.3%; P < .001). CONCLUSIONS: In a group of persons at increased risk for CRC, CT colonography compared with colonoscopy resulted in a negative predictive value of 96.3% overall. When limited to FOBT-positive persons, the negative predictive value was 84.9%.


Asunto(s)
Colonografía Tomográfica Computarizada , Neoplasias Colorrectales/diagnóstico por imagen , Adulto , Anciano , Colonoscopía , Neoplasias Colorrectales/diagnóstico , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Factores de Riesgo , Sensibilidad y Especificidad
9.
Diagn Cytopathol ; 47(4): 315-319, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30417984

RESUMEN

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors that can affect any part of the body. They can be sporadic or arise in the setting of tuberous sclerosis (TSC). In this article, we report a series of three hepatic and two pancreatic PEComas diagnosed preoperatively with ultrasound-guided fine needle aspiration (FNA). All patients were female (age range 28-70), had no personal history of TSC and presented with a single, localized painless mass. Rapid on-site evaluation (ROSE) of cytologic samples was performed for all cases to evaluate for cellular content and adequacy of specimens. Direct smears and cell block preparations revealed a proliferation of medium to large polygonal epithelioid cells, with abundant eosinophilic and vacuolated cytoplasm, arranged in sheets and nests. On immunohistochemistry (IHC), neoplastic cells showed co-expression of melanocytic and smooth muscle markers and a diagnosis of PEComa was rendered. PEComas of the pancreas and liver are rare neoplasms, but should always be considered when examining "clear cell" neoplasms, especially in young female patients. If good quality cytologic samples are obtained by FNA, a correct diagnosis can be achieved with the help of IHC. This is of particular importance in order to plan adequate surgical strategy and to avoid overtreatment.


Asunto(s)
Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/normas , Neoplasias Hepáticas/patología , Neoplasias Pancreáticas/patología , Neoplasias de Células Epitelioides Perivasculares/patología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas
10.
Eur J Gastroenterol Hepatol ; 15(12): 1323-31, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14624156

RESUMEN

OBJECTIVE: To describe the experience of a radiology unit in using open access computed tomography (CT) colonography instead of double-contrast barium enema in patients who refused or had an incomplete first-attempt colonoscopy. METHODS: All consecutive patients who underwent CT colonography from December 1998 to August 2001 were recalled and evaluated. Patients in whom CT colonography showed intraluminal growths were sent for colonoscopy, performed using deep sedation if the first attempt failed. RESULTS: A total of 463 consecutive CT colonography examinations were performed: 304 patients were re-traceable and were evaluated. In 85 cases CT colonography reported the presence of intraluminal growth. Colonoscopy confirmed the presence of 74 of the 94 polyps, and of 43 of the 48 cancers found at CT colonography. Colonoscopy also diagnosed an additional two cancers in two patients with CT colonography findings of inflammatory changes, and an additional 26 polyps in 16 patients. On a per-lesion basis, the positive predictive value of CT colonography was 73%, 80% and 87% for polyps /= 10 mm, respectively, and was 90% for cancer. On a per-patient basis, the positive predictive value was 60%, 72% and 89% for lesions /= 10 mm, respectively, and was 93% for cancer. CONCLUSION: CT colonography on an open access basis can be confidently used as a routine test instead of double-contrast barium enema when total colonoscopy cannot be performed.


Asunto(s)
Pólipos del Colon/diagnóstico por imagen , Colonografía Tomográfica Computarizada/métodos , Neoplasias Colorrectales/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Sulfato de Bario , Pólipos del Colon/diagnóstico , Pólipos del Colon/patología , Colonoscopía , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/patología , Medios de Contraste , Enema , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados
11.
Comput Med Imaging Graph ; 33(4): 325-31, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19304454

RESUMEN

An automatic method for the segmentation of the colonic wall is proposed for abdominal computed tomography (CT) of the cleansed and air-inflated colon. This multistage approach uses an adaptive 3D region-growing algorithm, with a self-adjusting growing condition depending on local variations of the intensity at the air-tissue boundary. The method was evaluated using retrospectively collected CT scans based on visual segmentation of the colon by expert radiologists. This evaluation showed that the procedure identifies 97% of the colon segments, representing 99.8% of the colon surface, and accurately replicates the anatomical profile of the colonic wall. The parameter settings and performance of the method are relatively independent of the scanner and acquisition conditions. The method is intended for application to the computer-aided detection of polyps in CT colonography.


Asunto(s)
Algoritmos , Inteligencia Artificial , Colon/diagnóstico por imagen , Colonografía Tomográfica Computarizada/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Humanos , Aumento de la Imagen/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
13.
Chemistry ; 13(36): 10088-95, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17907129

RESUMEN

The reaction of [Ru(2)Cl(O(2)CMe)(DPhF)(3)] (DPhF=N,N'-diphenylformamidinate) with aqueous HCl leads to the substitution of the acetate ligand to give the complex [Ru(2)Cl(2)(DPhF)(3)] (1). Similar reaction of [Ru(2)(O(2)CMe)(DPhF)(3)(H(2)O)]BF(4) with aqueous HBr or HI produces [Ru(2)Br(2)(DPhF)(3)] (2), and [Ru(2)I(2)(DPhF)(3)] (3), respectively. The reaction of 1 with AgBF(4) to form the highly unsaturated unit [Ru(2)(DPhF)(3)](2+), which is isolated as [Ru(2)(BF(4))(DPhF)(3)(H(2)O)]BF(4) (4), and [Ru(2)(MeCN)(2)(DPhF)(3)](BF(4))(2) (5), is also reported. The use of AgNO(3) instead of AgBF(4) leads to [Ru(2)(NO(3))(2)(DPhF)(3)] (6). The magnetic behaviour of complexes 1-4 and 6 is intermediate between high- and low-spin configurations. A relationship between the magnetic behaviour and the visible-near-infrared (Vis-NIR) spectra is apparent. In addition, the crystal structure determinations of 2, 4.THF, and 6, have been carried out. Complexes 1-3, 5 and 6 are the first examples of open-paddlewheel structures in diruthenium chemistry. The BF(4) (-) bridging the metal centres in 4THF is activated and forms very short Ru-F bonds.

14.
Inorg Chem ; 45(9): 3639-47, 2006 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-16634596

RESUMEN

The reaction of Ru2Cl(O2CMe)(DPhF)3 (DPhF = N,N'-diphenylformamidinate) with mono- and polycarboxylic acids gives a clean substitution of the acetate ligand, leading to the formation of complexes Ru2Cl(O2CC6H5)(DPhF)3 (1), Ru2Cl(O2CC6H4-p-CN)(DPhF)3 (2), [Ru2Cl(DPhF)3(H2O)]2(O2C)2 (3), [Ru2Cl(DPhF)3]2[C6H4-p-(CO2)2] (4), and [Ru2Cl(DPhF)3]3[C6H3-1,3,5-(CO2)3] (5). The preparation of [Ru2(NCS)(DPhF)3]3[C6H3-1,3,5-(CO2)3] (6) and {[Ru2(DPhF)3(H2O)]3[C6H3-1,3,5-(CO2)3]}(SO3CF3)3 (7) from 5 is also described. All complexes are characterized by elemental analysis, IR and electronic spectroscopy, mass spectrometry, cyclic voltammetry, and variable-temperature magnetic measurements. The crystal structure determinations of complexes 2.0.5THF and 3.THF.4H2O (THF = tetrahydrofuran) are reported. The reactions carried out demonstrate the high chemical stability of the fragment [Ru2(DPhF)3]2+, which is preserved in all tested experimental conditions. The stability of this fragment is also corroborated by the mass spectra. Electrochemical measurements reveal in all complexes one redox process due to the equilibrium Ru2(5+) <--> Ru2(6+). In the polynuclear complex 7, some additional oxidation processes are also observed that have been ascribed to the presence of two types of dimetallic units rather than two consecutive reversible oxidations. The magnetic behavior toward temperature for complexes 1-7 from 300 to 2 K is analyzed. Complexes 1-7 show low values of antiferromagnetic coupling in accordance with the molecular nature in 1 and 2 and the absence of important antiferromagnetic interaction through the carboxylate bridging ligands in 3-7, respectively. In addition, the magnetic properties of complex 7 do not correspond to any magnetic behavior described for diruthenium(II,III) complexes. The experimental data of compound 7 are simulated considering a physical mixture of S = 1/2 and 3/2 spin states. This magnetic study demonstrates the high sensitivity of the electronic configuration of the unit [Ru2(DPhF)3]2+ to small changes in the nature of the axial ligands. Finally, the energy gap between the pi and delta orbitals in these types of compounds allows the tentative assignment of the transition pi --> delta.

15.
Eur Radiol ; 16(8): 1745-9, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16636802

RESUMEN

Our purpose was to assess the effect of reader experience, fatigue, and scan findings on interpretation time for CT colonography. Nine radiologists (experienced in CT colonography); nine radiologists and ten technicians (both groups trained using 50 validated examinations) read 40 cases (50% abnormal) under controlled conditions. Individual interpretation times for each case were recorded, and differences between groups determined. Multi-level linear regression was used to investigate effect of scan category (normal or abnormal) and observer fatigue on interpretation times. Experienced radiologists (mean time 10.9 min, SD 5.2) reported significantly faster than less experienced radiologists and technicians; odds ratios of reporting times 1.4 (CI 1.1, 1.8) and 1.6 (1.3, 2.0), respectively (P

Asunto(s)
Competencia Clínica , Colonografía Tomográfica Computarizada/normas , Fatiga/fisiopatología , Europa (Continente) , Humanos , Modelos Lineales , Variaciones Dependientes del Observador , Factores de Tiempo
16.
Eur Radiol ; 16(8): 1737-44, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16636803

RESUMEN

The extent measurement error on CT colonography influences polyp categorisation according to established management guidelines is studied using twenty-eight observers of varying experience to classify polyps seen at CT colonography as either 'medium' (maximal diameter 6-9 mm) or 'large' (maximal diameter 10 mm or larger). Comparison was then made with the reference diameter obtained in each patient via colonoscopy. The Bland-Altman method was used to assess agreement between observer measurements and colonoscopy, and differences in measurement and categorisation was assessed using Kruskal-Wallis and Chi-squared test statistics respectively. Observer measurements on average underestimated the diameter of polyps when compared to the reference value, by approximately 2-3 mm, irrespective of observer experience. Ninety-five percent limits of agreement were relatively wide for all observer groups, and had sufficient span to encompass different size categories for polyps. There were 167 polyp observations and 135 (81%) were correctly categorised. Of the 32 observations that were miscategorised, 5 (16%) were overestimations and 27 (84%) were underestimations (i.e. large polyps misclassified as medium). Caution should be exercised for polyps whose colonographic diameter is below but close to the 1-cm boundary threshold in order to avoid potential miscategorisation of advanced adenomas.


Asunto(s)
Pólipos del Colon/diagnóstico por imagen , Colonografía Tomográfica Computarizada , Distribución de Chi-Cuadrado , Competencia Clínica , Pólipos del Colon/patología , Colonoscopía , Diagnóstico Diferencial , Europa (Continente) , Femenino , Humanos , Masculino , Variaciones Dependientes del Observador , Estadísticas no Paramétricas
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