Purpose
To investigate whether locoregional staging of colon cancer by experienced radiologists can be improved by training and feedback to minimize the risk of over-staging into the context of ...patient selection for neoadjuvant therapy and to identify potential pitfalls of CT staging by characterizing pathologic traits of tumors that remain challenging for radiologists.
Methods
Forty-five cases of stage I-III colon cancer were included in this retrospective study. Five experienced radiologists evaluated the CTs; 5 baseline scans followed by 4 sequential batches of 10 scans. All radiologists were trained after baseline scoring and 2 radiologists received feedback. The learning curve, diagnostic performance, reader confidence, and reading time were evaluated with pathologic staging as reference. Pathology reports and H&E slides of challenging cases were reviewed to identify potential pitfalls.
Results
Diagnostic performance in distinguishing T1-2 vs. T3-4 improved significantly after training and with increasing number of reviewed cases. Inaccurate staging was more frequently related to under-staging rather than over-staging. Risk of over-staging was minimized to 7% in batch 3–4. N-staging remained unreliable with an overall accuracy of 61%. Pathologic review identified two tumor characteristics causing under-staging for T-stage in 5/7 cases: (1) very limited invasive part beyond the muscularis propria and (2) mucinous composition of the invading part.
Conclusion
The high accuracy and specificity of T-staging reached in our study indicate that sufficient training and practice of experienced radiologists can ensure high validity for CT staging in colon cancer to safely use neoadjuvant therapy without significant risk of over-treatment, while N-staging remained unreliable.
Purpose
Adequate monitoring of changes in tumor load is fundamental for the assessment of the course of disease and response to treatment. There is an ongoing debate on the utility of RECIST v1.1 in ...gastroenteropancreatic neuroendocrine tumors (GEP-NETs).
Methods
In this retrospective real-life cohort study, Choi-criteria were compared with RECIST v1.1. The agreement between both criteria and the association with survival endpoints were evaluated.
Results
Seventy-five patients were included with a median follow-up of 35 months (range 8–53). Median progression-free survival (mPFS) according to RECIST v1.1 was 15 months (range 2–50) compared to 14 months (range 2–50) in Choi. According to RECIST, 33 (44%) patients were classified as having stable disease (SD), 40 (53%) as progressive disease (PD) and two (3%) patients as partial response (PR), compared to 9 (12%) patients classified as SD, 50 (67%) as PD and 16 (21%) as PR according to Choi-criteria. Overall concordance between the criteria was moderate (Cohen’s Kappa = 0.408,
p
< 0.001) and agreement varied between 57 and 69% at each consecutive scan (
p
< 0.001). Survival analysis showed significant differences in overall survival (OS) for RECIST v1.1 categories PD and non-PD (log-rank
p
= 0.02), however, in Choi no significant differences in OS were found (
p
= 0.27).
Conclusion
RECIST v1.1 had a better clinical utility and prognostic value compared to Choi-criteria. Still, RECIST were also not sufficient to adequately predict OS. This outlines the need for new tools that provides accurate information on the disease course and treatment response to support precise prognostication in patients with GEP-NETs.
Graphical abstract
Hypoxic-ischemic cerebral changes can be difficult to distinguish from normal myelination on T1-weighted images. We hypothesized that comparing signal intensity (SI) of brain structures on ...T1-weighted images enables differentiation of myelination from hypoxic-ischemic brain damage.
T1-weighted images, obtained in 57 infants aged 1-104 days and born after a gestational age of 35 weeks or older, were retrospectively evaluated. Subjects were assigned to a patient (n = 23, with perinatal hypoxic-ischemic encephalopathy HIE stage 2/3) or a control group (n = 34). In each subject, an SI score was assigned to 19 brain structures on the basis of pairwise comparisons with the other 18 structures. In both groups, mean total SI scores were calculated for the 19 structures. Independent samples t tests assessed whether the mean total score of a structure differed significantly between the 2 groups. Logistic regression assessed which comparison was best to distinguish between the groups and to predict the presence of hypoxic-ischemic injury.
In patients, mean total SI scores for posterolateral putamen (PP) and peri-Rolandic cortex (PC) were significantly higher (P = .000 for both). Mean total SI scores of the posterior limb of internal capsule (PLIC) and the corona radiata (CR) were significantly lower in patients (P = .000 and 0.005, respectively). Two comparisons (PLIC versus CR, PP versus PC) were best to distinguish patients and controls and to predict absence or presence of HIE (P < .0001).
SI changes due to hypoxia-ischemia can be differentiated from normal myelination by comparing SI of 4 brain structures on T1-weighted images.
Background
Schwannomas are rare tumours that pose a significant management challenge in the abdomen, retroperitoneum and pelvis. No data are available to inform management strategy.
Methods
A ...collaborative international cohort study, across specialist sarcoma units, was conducted to include adults presenting between 2000 and 2017 with histopathologically confirmed schwannomas within the abdomen, retroperitoneum or pelvis.
Results
Of 485 patients across 12 centres, 38 (7·8 per cent) were discharged without follow‐up, 199 (41·0 per cent) underwent early resection and 248 (51·1 per cent) had radiological monitoring. Of these 248 patients, 96 (38·7 per cent) eventually had surgery, giving an overall resection rate of 60·8 per cent (295 of 485). At baseline, median tumour volume was 90·1 (i.q.r. 26·5–262·0) cm3. The estimated growth rate was 10·5 (95 per cent c.i. 9·4 to 11·6) per cent per year, and was consistent in the short term (within 2 years of diagnosis) and long term (beyond 2 years) (ρ = 0·405, P = 0·021). A decision to operate was more common in symptomatic patients (P < 0·001) and for rapidly growing tumours (growth rate more than 20 per cent per year) (P = 0·025). R0/R1 resection was achieved in 91·6 per cent of patients (263 of 287). Kaplan–Meier long‐term recurrence rates after R0/R1 resection were 2·3 and 6·7 per cent at 3 and 5 years respectively.
Conclusion
Specific recommendations include: indications for early surgery, prediction of growth from radiological monitoring, promotion of selective submacroscopic resection and cessation of postoperative imaging surveillance.
Antecedentes
Los schwannomas son tumores raros que plantean un importante desafío para su tratamiento en el abdomen, retroperitoneo y pelvis. No existen datos disponibles que informen de la estrategia de tratamiento.
Métodos
Se llevó a cabo un estudio de cohortes colaborativo internacional, entre unidades especializadas en sarcomas, que incluía a pacientes adultos con schwannomas de la cavidad abdominal, retroperitoneo o pelvis con confirmación histológica que se presentaron entre 2000 y 2017.
Resultados
De 485 pacientes de los 12 centros, 38 (7,8%) fueron dados de alta sin seguimiento, 199 (41,0%) fueron sometidos a resección precoz y 248 (51,1%) pacientes se incluyeron en seguimiento radiológico, de estos últimos 96 pacientes (38,7%) fueron sometidos finalmente a cirugía, con una tasa global de resección del 60,8% (295/485). Al inicio, la mediana del volumen tumoral fue 90,1 cm3 (rango intercuartílico: 26,5‐262,0). La tasa media de crecimiento fue 10,5% por año (i.c. del 95%: 9,4%‐11,6%), siendo uniforme en el seguimiento a corto (durante los 2 años del diagnóstico) y largo plazo (más allá de los 2 años, rho: 0,405, P = 0,021). La decisión de establecer la indicación quirúrgica fue más frecuente en pacientes sintomáticos (P < 0,001) y en tumores con crecimiento rápido (> 20% por año, P = 0,025). Se consiguió una resección R0/R1 en el 91,6%. Las tasas de recidiva a largo plazo de Kaplan‐Meier tras resección R0/R1 fueron 2% y 7% a 3 y 5 años, respectivamente.
Conclusión
Las recomendaciones específicas incluyen: indicaciones para la cirugía precoz, predicción del crecimiento en el seguimiento radiológico, fomentar la resección submacroscópica selectiva, y cese del seguimiento postoperatorio con pruebas de imagen.
Schwannomas present a significant management challenge, and surgery can result in morbidity. Individualized growth rates predicted after a period of radiological monitoring can help guide decision‐making. There is no role for surveillance after resection.
Practical guidelines
Contactless underwater power delivery Heeres, B.J.; Novotny, D.W.; Divan, D.M. ...
Proceedings of 1994 Power Electronics Specialist Conference - PESC'94,
1994, Letnik:
1
Conference Proceeding
A power conversion and distribution system for contactless underwater power delivery utilizing a coaxial winding transformer is proposed. The issues of underwater power delivery including the ...additional impedance and power dissipation in the system due to the sea water are discussed. Design considerations for the coaxial winding transformer are presented. Topologies for both the primary and secondary power converters and designs for the transmission cable are explored. Several applications and advantages of the system are given.< >
A comprehensive experimental and modelling study on the acid-catalysed hydrolysis of the water hyacinth plant (
Eichhornia crassipes) to optimise the yield of levulinic acid (LA) is reported (
T
=
...150–175
°C,
C
H
2
SO
4
=
0.1
–
1
M
, water hyacinth intake
=
1–5
wt%). At high acid concentrations (>0.5
M), LA was the major organic acid whereas at low acid concentrations (<0.1
M) and high initial intakes of water hyacinth, the formation of propionic acid instead of LA was favoured. The highest yield of LA was 53
mol% (35
wt%) based on the amount of C6-sugars in the water hyacinth (
T
=
175
°C,
C
H
2
SO
4
=
1
M
, water hyacinth intake
=
1
wt%). The LA yield as a function of the process conditions was modelled using a kinetic model originally developed for the acid-catalysed hydrolysis of cellulose and good agreement between the experimental and modelled data was obtained.
PDF
