Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where S.M. Imhof is active.

Publication


Featured researches published by S.M. Imhof.


Annals of Neurology | 2006

Neonatal porencephaly and adult stroke related to mutations in collagen IV A1

Marjo S. van der Knaap; Leo M. E. Smit; Frederik Barkhof; Yolande A.L. Pijnenburg; Sonja Zweegman; Hans W.M. Niessen; S.M. Imhof; Peter Heutink

The objective of this study was to describe leukoencephalopathy, lacunar infarcts, microbleeds and macrobleeds in the context of a collagen IV A1 mutation.


Health and Quality of Life Outcomes | 2007

Health-related quality of life of child and adolescent retinoblastoma survivors in the Netherlands.

Jennifer van Dijk; Jaap Huisman; Annette C. Moll; Antoinette Y. N. Schouten-van Meeteren; Pieter Dirk Bezemer; Peter J. Ringens; Peggy T. Cohen-Kettenis; S.M. Imhof

BackgroundTo assess health-related quality of life (HRQoL) in children (8–11 years) and adolescents (12–18 years) who survived retinoblastoma (RB), by means of the KIDSCREEN self-report questionnaire and the proxy-report version.MethodsThis population-based cross-sectional study (participation rate 70%) involved 65 RB survivors (8–18 years) and their parents. Child/adolescents and parents perception of their youths HRQoL was assessed using the KIDSCREEN, and the results were compared with Dutch reference data. Relations with gender, age, marital status of the parents, and visual acuity were analyzed.ResultsRB survivors reported better HRQoL than did the Dutch reference group on the dimensions moods and emotions and autonomy. Increased ratings of HRQoL in RB survivors were mainly seen in perceptions of the younger children and adolescent girls. RB survivors with normal visual acuity scored higher on physical well-being than visually impaired survivors. Age was negatively associated with the dimensions psychological well-being, self-perception (according to the child and parent reports) and parent relations and home life (according to the child). Self-perception was also negatively associated with visual acuity (according to the child). Only parents of young boys surviving RB reported lower on autonomy than the reference group, and parents of low visual acuity and blind RB survivors reported higher on autonomy than parents of visually unimpaired survivors. Survivors perceptions and parents perceptions correlated poorly on all HRQoL dimensions.ConclusionRB survivors reported a very good HRQoL compared with the Dutch reference group. The perceptions related to HRQoL differ substantially between parents and their children, i.e. parents judge the HRQoL of their child to be relatively poorer. Although the results are reassuring, additional factors of HRQoL that may have more specific relevance, such as psychological factors or coping skills, should be explored.


American Journal of Neuroradiology | 2012

Single-Shot Turbo Spin-Echo Diffusion-Weighted Imaging for Retinoblastoma: Initial Experience

P. de Graaf; Petra J. W. Pouwels; Firazia Rodjan; A.C. Moll; S.M. Imhof; Dirk L. Knol; Esther Sanchez; P. van der Valk; J. A. Castelijns

BACKGROUND AND PURPOSE: Retinoblastoma may exhibit variable hyperintensities on DWI, resulting in different values in the ADC maps, depending on their histology and cellularity. However, EP-based DWI has susceptibility artifacts and image distortions, which make DWI of the orbit a challenging technique. The aim of this study was to investigate the feasibility of single-shot turbo spin-echo (HASTE) DWI in the evaluation of children with retinoblastoma and to assess the value of ADC maps in differentiating viable and necrotic tumor tissue. MATERIALS AND METHODS: Two radiologists assessed conventional MR images, DWI, and ADC maps of 17 patients with retinoblastoma (n = 17 eyes). Non-EP DWI was performed by using a HASTE sequence with b-values of 0 and 1000 s/mm2. ADC values were measured for enhancing and nonenhancing tumor tissue. ADC maps were compared with histopathologic findings regarding tumor differentiation and viability. RESULTS: On DWI, vital tumor tissue showed hyperintensity with negligible intensity of surrounding vitreous. The difference in mean (range) ADC values between enhancing (1.03 [0.72–1.22] × 10−3 mm2 s−1) and nonenhancing (1.47 [0.99–1.80] × 10−3 mm2 s−1) parts of retinoblastoma was statistically significant (P < .0005). Nonenhancing tumor parts showed a significantly lower ADC compared with vitreous (2.67 [2.24–3.20]×10−3 mm2 s−1) (P < .0005) and subretinal fluid (2.20 [1.76–2.96] × 10−3 mm2 s−1) (P < .0005). Histopathologically, low ADC values (enhancing tumor part) correlated to viable tumor tissue, whereas intermediate ADC values (nonenhancing tumor parts) correlated to necrotic tumor tissue. CONCLUSIONS: HASTE DWI allowed adequate characterization of retinoblastoma, and ADC is a helpful tool to differentiate viable and necrotic tumor tissue and might be valuable in monitoring the response to eye-preserving therapies.


Health and Quality of Life Outcomes | 2007

Quality of life of adult retinoblastoma survivors in the Netherlands

Jennifer van Dijk; S.M. Imhof; Annette C. Moll; Peter J. Ringens; Peggy T. Cohen-Kettenis; Frank Rijmen; Jaap Huisman

BackgroundTo assess the quality of life (QoL) and predictors thereof in Dutch adult hereditary and non-hereditary retinoblastoma (RB) survivors.MethodsIn this population-based cross-sectional study, a generic QoL questionnaire (SF-36) and a disease-specific interview were administered to 87 adult RB survivors aged 18 to 35 years. Their QoL data were compared with those of a Dutch healthy reference group. Among the RB hereditary/non-hereditary survivors, the QoL was compared and predictors for QoL were identified by linear multiple regression analyses.ResultsAs a group, RB survivors scored significantly lower than the reference group on the SF-36 subscale mental health (t = -27, df = 86, p < 0.01). Hereditary RB survivors scored lower on the subscale general health (t = 2.6, df = 85, p < 0.01) than non-hereditary RB survivors. Having experienced bullying, as a child was a predictor for the SF-36 subscales: physical functioning (p < 0.05), role functioning physical (p < 0.01), role functioning emotional (p < 0.05) and social functioning (p < 0.01). Having experienced bullying (p < 0.01), but also subjective experience of impairment related to RB (p < 0.05), was predictors for general health. Subjective experience of impairment was a predictor for vitality (p < 0.01) and bodily pain (p < 0.01).ConclusionIn this exploratory study, it appears that the group of adult RB survivors experience a relatively good overall but slightly decreased QoL compared with the reference group. However, they report more problems with regard to their mental health (anxiety, feelings of depression, and loss of control). Hereditary RB survivors differ significantly from non-hereditary RB survivors only in general health. Bullying in childhood and subjective experience of impairment are the main predictors of a worse QoL. In order to prevent worsening of QoL, or perhaps to improve it, clinicians should make an inventory of these issues at an early stage. We recommend further research to assess the specific psychological factors that may lead to mental health problems in this population.


British Journal of Ophthalmology | 2006

Retinoblastoma and optic nerve enhancement on MRI: not always extraocular tumour extension

P. de Graaf; Annette C. Moll; S.M. Imhof; P. van der Valk; Jonas A. Castelijns

Neoadjuvant chemotherapy is useful in the management of extensive forms of retinoblastoma with radiologically detectable optic nerve invasion at diagnosis.1 Magnetic resonance imaging (MRI) can detect various degrees of optic nerve invasion as enhancement extending from an intraocular tumour into the optic nerve. However, pretreatment false positive MRI findings based on inflammation occur occasionally.2 We describe a case of unilateral retinoblastoma and false positive MRI findings of extensive optic nerve involvement.nnA 3 year old girl presented with retinoblastoma of the right eye. Ophthalmic examination revealed a large exophytic growing tumour, a shallow anterior chamber, rubeosis iridis, and an elevated intraocular pressure. T2WI showed a hypointense subretinal tumour mass with similar signal intensity (SI) compared to both optic nerves (fig 1A). No delineation of the ipsilateral optic nerve with surrounding cerebrospinal fluid was possible. On additional short tau inversion recovery (STIR) MRI, the optic nerve showed an increased SI from the postlaminar part to the orbital apex. Contrast enhanced T1WI showed enhancement of the tumour mass (tumour volume 2.1 cm3). Thickening and marked enhancement …


American Journal of Neuroradiology | 2010

Brain Abnormalities on MR Imaging in Patients with Retinoblastoma

Firazia Rodjan; P. de Graaf; A.C. Moll; S.M. Imhof; J.I.M.L Verbeke; Esther Sanchez; J. A. Castelijns

BACKGROUND AND PURPOSE: Although pineoblastoma is the main brain abnormality associated with hereditary retinoblastoma, recent studies suggest an association with pineal cysts. This association is important because some pineoblastomas mimic pineal cysts. If there is a relationship, then radiologists should be aware of it because diagnostic confusion is possible. Mental retardation and congenital brain anomalies are also reported in patients with retinoblastoma, mostly in combination with 13q deletion syndrome. In this retrospective study, the presence of brain abnormalities on MR images in a large group of consecutive patients with retinoblastoma is evaluated. MATERIALS AND METHODS: Brain MR images of 168 patients with retinoblastoma from 1989 to 2009 were evaluated by 2 radiologists for tumors, structural anomalies, myelinization, and coincidental findings. Clinical records were reviewed for laterality, heredity, and the presence of the 13q deletion syndrome. RESULTS: The hereditary group (patients with bilateral and unilateral proved RB1-germline mutation) included 90 (54%) of 168 patients. Seven patients had 13q deletion syndrome. Normal findings on brain MR images were seen in 150 (89%) patients. Five pineoblastomas were detected, all in patients with hereditary retinoblastoma (5.5% in the hereditary subgroup). Nine pineal cysts were detected (2.2% in the hereditary subgroup). Corpus callosum agenesis was found in 1 patient and a Dandy-Walker variant in 1 patient, both in combination with 13q deletion syndrome. CONCLUSIONS: Pineoblastoma is associated with hereditary retinoblastoma, and structural brain abnormalities are restricted to patients with the 13q deletion syndrome. The incidence of pineal cysts in patients with retinoblastomas is similar to that in healthy children and is not associated with hereditary retinoblastoma.


American Journal of Neuroradiology | 2010

Contrast-Enhancement of the Anterior Eye Segment in Patients with Retinoblastoma: Correlation between Clinical, MR Imaging, and Histopathologic Findings

P. de Graaf; P. van der Valk; A.C. Moll; S.M. Imhof; A.Y.N. Schouten-van Meeteren; Dirk L. Knol; J. A. Castelijns

BACKGROUND AND PURPOSE: AES contrast-enhancement is recognized in a substantial number of retinoblastoma-affected eyes. We retrospectively investigated the histopathologic basis of AES contrast-enhancement on MR images in retinoblastoma. MATERIALS AND METHODS: Pretreatment contrast-enhanced MR images were obtained from 42 children with retinoblastoma. Forty-two enucleated eyes were included in this study, AES enhancement was evaluated by using a 3-point score, and these data were correlated with clinical, MR imaging, and histopathologic findings. Additionally, 14 specimens were immunohistochemically analyzed for CD31, VEGF, and Flt-1 expression. Statistical correlations with AES enhancement were assessed by using a linear-by-linear association test and univariate and multivariate ordinal regressions. RESULTS: The degree of abnormal AES enhancement was moderate in 15 (36%) eyes and strong in 14 (33%) eyes, whereas 13 (31%) eyes showed normal AES enhancement. In multivariate analysis, the degree of AES enhancement showed statistically significant correlations with iris surface-vessel count (P = .05) and optic nerve invasion (P = .04) in the enucleated eye and with tumor volume (P = .02) as detected on MR imaging. No significant associations between AES enhancement and VEGF expression in the iris were observed. Flt-1 (P = .04) staining in iris stroma and IA as detected with CD31 staining (P = .009) both yielded a statistically significant positive correlation with abnormal AES enhancement. CONCLUSIONS: The degree of abnormal AES enhancement on MR imaging in retinoblastoma reflects angiogenesis in the iris. AES enhancement is also a hallmark of advanced retinoblastoma because its degree correlates with tumor volume and optic nerve invasion.


Psycho-oncology | 2009

Coping strategies of retinoblastoma survivors in relation to behavioural problems

J. van Dijk; Martha A. Grootenhuis; S.M. Imhof; Peggy T. Cohen-Kettenis; Annette C. Moll; Jaap Huisman

Objective: To assess coping strategies of long‐term retinoblastoma (RB) survivors and explore determinants of behavioural functioning, including medical, socio‐demographic and coping variables.


Psycho-oncology | 2009

Behavioural functioning of retinoblastoma survivors

J. van Dijk; Kim J. Oostrom; S.M. Imhof; Annette C. Moll; A.Y.N. Schouten-van Meeteren; Pieter Dirk Bezemer; Jaap Huisman

Objective: To assess behavioural problems in retinoblastoma (RB) survivors.


Ophthalmic Genetics | 2004

Fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to detect vital retinoblastoma in the eye: Preliminary experience

Annette C. Moll; O.S. Hoekstra; S.M. Imhof; E.F. Comans; A.Y.N. Schouten-van Meeteren; P. van der Valk; Maarten Boers

Background/aims: To report our first experience with FDG-PET in the detection of vital retinoblastoma. Methods: Four newly diagnosed retinoblastoma patients, two treated retinoblastoma patients, and four control patients were enrolled in this pilot study. F18-FDG uptake was assessed in the light of clinical and histopathological features. Results: PET discriminated between new patients and controls, although tumor uptake varied widely. PET added no useful information with regard to possible vital tissue in tumor scars in the eye of the two treated retinoblastoma patients. Moreover, PET findings did not correlate with clinical or histopathological features. Conclusion: Based on this small pilot study, F18-PET shows little promise in the detection of retinoblastoma. More research on other radiofarmacons is recommended.

Collaboration


Dive into the S.M. Imhof's collaboration.

Top Co-Authors

Avatar

Annette C. Moll

VU University Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

P. de Graaf

VU University Medical Center

View shared research outputs
Top Co-Authors

Avatar

A.C. Moll

University of Amsterdam

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Jaap Huisman

VU University Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Dirk L. Knol

VU University Medical Center

View shared research outputs
Researchain Logo
Decentralizing Knowledge