1
|
van Gemert MJC, VanBavel E, Nikkels PGJ, van Leeuwen TG. Comment to Noll et al. "Artery-to-vein anastomoses in unequally divided placentas and their association with birthweight discordance". Placenta 2024; 151:26. [PMID: 38677264 DOI: 10.1016/j.placenta.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/14/2024] [Indexed: 04/29/2024]
Affiliation(s)
- Martin J C van Gemert
- Amsterdam UMC, University of Amsterdam, Biomedical Engineering & Physics, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.
| | - Ed VanBavel
- Amsterdam UMC, University of Amsterdam, Biomedical Engineering & Physics, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Peter G J Nikkels
- Department of Pathology, Wilhelmina's Children's Hospital, University Medical Center, Utrecht, the Netherlands
| | - Ton G van Leeuwen
- Amsterdam UMC, University of Amsterdam, Biomedical Engineering & Physics, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| |
Collapse
|
2
|
van Gemert MJC, van Leeuwen TG. Fluence is unequal to incident energy density or radiant exposure. Lasers Surg Med 2024; 56:125. [PMID: 38018690 DOI: 10.1002/lsm.23745] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 11/19/2023] [Indexed: 11/30/2023]
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, University of Amsterdam, Amsterdam, The Netherlands
| | - Ton G van Leeuwen
- Department of Biomedical Engineering & Physics, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
3
|
van Gemert MJC, Vlaming M, Gabaeff SC, Nikkels PGJ, Neumann HAM. Asymptomatic Infant Rib Fractures Are Primarily Non-abuse-Related and Should Not Be Used to Assess Physical Child Abuse. Children (Basel) 2023; 10:1827. [PMID: 38002918 PMCID: PMC10670409 DOI: 10.3390/children10111827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/27/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023]
Abstract
Finding infant rib fractures was for many years an almost undisputed proof that physical child abuse took place. Yet, these rib fractures are virtually always occult and asymptomatic and are only identified when looked for, usually with X-rays, from physical child abuse accusations related to, e.g., suspicion of the shaken baby syndrome. In a recent systematic literature review (searched in Cochran, Embase, PubMed and Sociological Abstracts), Güvensel questioned the diagnostic accuracy of rib fractures to be caused by abuse, due to lack of sufficient scientific evidence. Further, there is currently a world-wide disagreement between physicians considering themselves child abuse specialized, and physicians that explore non-abuse-related symptoms that may mimic physical abuse, which, it is hoped, will significantly reduce current unjustified child abuse diagnoses. In an attempt to help resolving this disagreement, we hypothesize that the probability of physical child abuse-related infant rib fractures is significantly lower than the probability of all other possible non-abuse-related causes of occult asymptomatic infant rib fractures, e.g., from birth trauma, prematurity, osteogenesis imperfecta, hypermobile Ehlers-Danlos Syndrome, severe chronic placental pathology (e.g., massive perivillous fibrin depositions and severe chronic histiocytic intervillositis), and vitamin-D deficiency. As method, we attempted to assess the incidence of these various causes of infant rib fractures, in the Netherlands and the USA. The results are that the estimated Dutch and USA physical abuse-related infant rib fracture incidences are at least about 250 and 45 times lower than the sum of all the non-abuse-related estimates. Because these latter rib fractures are occult and asymptomatic, it is likely that (many) more could be out there. In conclusion, occult asymptomatic rib fractures develop perinatally, virtually always as birth trauma, in infants with sufficiently weak bones due to vitamin D deficiency, transmitted by their vitamin D deficient pregnant mothers. This group also includes cortical rib cracks due to deformation forces, with an estimated 186/100,000 incidence. And, despite obvious uncertainties in all estimated incidences, we provided strong evidence that our hypothesis has relevance, implying that the abundant occult asymptomatic rib fractures, when found in infants, should not be used to assess potential physical child abuse.
Collapse
Affiliation(s)
- Martin J. C. van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers, Location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Marianne Vlaming
- Private Practice, Criminal Psychology and Law, 6986 CL Angerlo, The Netherlands;
| | | | - Peter G. J. Nikkels
- Department of Pathology, Wilhelmina Children’s Hospital, University Medical Center, 3584 CX Utrecht, The Netherlands;
| | | |
Collapse
|
4
|
Vlaming M, Sauer PJJ, Janssen EPF, van Koppen PJ, Bruijninckx CMA, Akkerman-Zaalberg van Zelst MWM, Neumann HAM, van Gemert MJC. Child Abuse, Misdiagnosed by an Expertise Center: Part I-Medico-Social Aspects. Children (Basel) 2023; 10:963. [PMID: 37371195 DOI: 10.3390/children10060963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/08/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023]
Abstract
Child abuse is a dangerous situation for an infant. Professionals need to weigh the risk of failing to act when children are seriously harmed against the serious harm done by carrying out safeguarding interventions. In severe cases, foster care might be advisable. The negative effects for the child's psychosocial development requires that such placement must be based on very solid evidence. Our aim is to identify why Dutch parents whose child may have a medical condition that could mimic symptoms of child abuse have a significant chance of being erroneously convicted and losing custody of their child. As a method, we describe and analyze the following case. An Armenian-Dutch newborn (uncomplicated term vaginal delivery), starting at two weeks after birth, developed small bruises on varying body locations. At two months, a Well-Baby Clinic physician referred the girl to a university hospital, mentioning that there were no reasons to suspect child abuse and that her Armenian grandmother easily bruised as well. However, before consultation by a pediatrician of the hospital-located Expertise Center for Child Abuse, the parents were suspected of child abuse. Based on the expertise center's protocols, skeletal X-rays were made, which showed three healed, asymptomatic rib fractures, while invalid statistics suggested, incorrectly, a 10-100 times more likely non-accidental than accidental cause of the symptoms (discussed in Part II of this series). The expertise enter physician ignored any argument that could show parental innocence, including the positive parent-child relationship reported by the Well-Baby Clinic and the general practitioner. The girl and her older brother were placed in a family foster home and then in a secret home. The case radically resolved when a large bruise also developed there, and an independent tissue disease specialist diagnosed a hereditary connective tissue disorder in the mother, implying that the girl's bruises and rib fractures could well be disease-related. In conclusion, if child abuse is suspected, and foster care placement considered, the patient and the parents should be thoroughly investigated by an independent experienced pediatrician together with an experienced pediatric clinical psychologist or psychotherapist to produce an independent opinion. Children deserve this extra safeguard before being separated from their parents.
Collapse
Affiliation(s)
- Marianne Vlaming
- Private Practice, Criminal Psychology and Law, 6986 CL Angerlo, The Netherlands
| | - Pieter J J Sauer
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center, 9713 GZ Groningen, The Netherlands
| | - Emile P F Janssen
- Private Practice, Rehabilitation Medicine & Consultancy, 6137 CL Sittard, The Netherlands
| | - Peter J van Koppen
- Department of Criminal Law and Criminology, Faculty of Law, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
| | | | | | | | - Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
5
|
van Gemert MJC, Zwinderman AH, Koppen PJV, Neumann HAM, Vlaming M. Child Abuse, Misdiagnosed by an Expertise Center-Part II-Misuse of Bayes' Theorem. Children (Basel) 2023; 10:children10050843. [PMID: 37238391 DOI: 10.3390/children10050843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023]
Abstract
A newborn girl had, from two weeks on, small bruises on varying body locations, but not on her chest. Her Armenian grandmother easily bruised, too. Her mother was diagnosed with hypermobility-type Ehlers-Danlos-Syndrome (hEDS), an autosomal dominant connective tissue disorder, with a 50% inheritance probability. Referral to a University Medical Center located "Dutch Expertise Center for Child Abuse" resulted (prior to consultation) in physical abuse suspicion. Protocol-based skeletal X-rays showed three healed, asymptomatic rib fractures. A protocol-based Bayesian likelihood ratio guesstimation gave 10-100, erroneously used to suggest a 10-100 times likelier non-accidental-than-accidental cause. Foster care placement followed, even in a secret home, where she also bruised, suggesting hEDS inheritance. Correct non-accidental/accidental Bayes' probability of symptoms is (likelihood ratio) × (physical abuse incidence). From the literature, we derived an infant abuse incidence between about ≈0.0009 and ≈0.0026 and a likelihood ratio of <5 for bruises. For rib fractures, we used a zero likelihood ratio, arguing their cause was birth trauma from the extra delivery pressure on the chest, combined with fragile bones as the daughter of an hEDS-mother. We thus derived a negligible abuse/accidental probability between <5 × 0.0009 <0.005 and <5 × 0.0026 <0.013. The small abuse incidence implies that correctly using Bayes' theorem will also miss true infant physical abuse cases. Curiously, because likelihood ratios assess how more often symptoms develop if abuse did occur versus non-abuse, Bayes' theorem then implies a 100% infant abuse incidence (unwittingly) used by LECK. In conclusion, probabilities should never replace differential diagnostic procedures, the accepted medical method of care. Well-known from literature, supported by the present case, is that (child abuse pediatrics) physicians, child protection workers, and judges were unlikely to understand Bayesian statistics. Its use without statistics consultation should therefore not have occurred. Thus, Bayesian statistics, and certainly (misused) likelihood ratios, should never be applied in cases of physical child abuse suspicion. Finally, parental innocence follows from clarifying what could have caused the girl's bruises (inherited hEDS), and rib fractures (birth trauma from fragile bones).
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Aeilko H Zwinderman
- Department of Clinical Epidemiology & Bio-Statistics, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Peter J van Koppen
- Department of Criminal Law and Criminology, Faculty of Law, VU University, 1081 HV Amsterdam, The Netherlands
| | | | - Marianne Vlaming
- Private Practice, Criminal Psychology and Law, 6986 CL Angerlo, The Netherlands
| |
Collapse
|
6
|
Milner TE, van Gemert MJC, Duco Jansen E. Ashley James Welch (A.J.). Lasers Surg Med 2022; 54:201. [PMID: 35049046 DOI: 10.1002/lsm.23520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 01/07/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Thomas E Milner
- Department of Biomedical Engineering, UC Irvine, Irvine, CA.,Department of Surgery, UC Irvine, Irvine, CA.,Beckman Laser Institute & Medical Clinic, UC Irvine, Irvine, CA
| | - Martin J C van Gemert
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN.,Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN.,Vanderbilt Biophotonics Center - Vanderbilt University, Nashville, TN
| |
Collapse
|
7
|
van Gemert MJC, van der Geld CWM, Ross MG, Nikkels PGJ, van den Wijngaard JPHM. Why does second trimester demise of a monochorionic twin not result in acardiac twinning? Birth Defects Res 2021; 113:1103-1111. [PMID: 33999519 PMCID: PMC8453882 DOI: 10.1002/bdr2.1926] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/04/2021] [Indexed: 11/12/2022]
Abstract
Background We previously explained why acardiac twinning occurs in the first trimester. We raised the question why a sudden demised monochorionic twin beyond the first trimester does not lead to acardiac twinning. We argued that exsanguinated blood from the live twin would strongly increase the demised twins' vascular resistance, preventing its perfusion and acardiac onset. However, our current hypothesis is that perfusion of the demised twin does occur but that it is insufficient for onset of acardiac twinning. Methods We analyzed blood pressures and flows in a vascular resistance model of a monochorionic twin pregnancy where one of the fetuses demised. The resistance model consists of a demised twin with a (former) placenta, a live twin and its placenta, and arterioarterial (AA) and venovenous placental anastomoses. We assumed that only twins with a weight of at least 33% of normal survived the first trimester and that exsanguination of more than 50% of its blood volume is fatal for the live twin. Results At 20 weeks, only AA anastomoses with radii ≲1 mm keep the exsanguinated blood volume below 50%. Then, perfusion of the deceased body with arterial blood from the live fetus is about 5–40 times smaller than when that body was alive. Beyond 20 weeks, this factor is even smaller. At 14 weeks, this factor is at most 2. Conclusion We hypothesize that this small perfusion flow of arterial blood prevents further growth of the deceased body and hence precludes onset of acardiac twinning.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands
| | - Cees W M van der Geld
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Michael G Ross
- Department of Obstetrics and Gynecology, Harbor UCLA Medical Center, Torrance, California, USA
| | - Peter G J Nikkels
- Department of Pathology, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands
| | | |
Collapse
|
8
|
van Gemert MJC, Ross MG, van den Wijngaard JPHM, Nikkels PGJ. Acardiac twin pregnancies part VI: Why does acardiac twinning occur only in the first trimester? Birth Defects Res 2021; 113:687-695. [PMID: 33580607 PMCID: PMC8247889 DOI: 10.1002/bdr2.1882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/20/2020] [Accepted: 01/30/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND Clinical observation suggests that acardiac twinning occurs only in the first trimester. In part, this contradicts our previous analysis (part IV) of Benirschke's concept that unequal embryonic splitting causes unequal embryo/fetal blood volumes and pressures. Our aim is to explain why acardiac onset is restricted to the first trimester. METHODS We applied the vascular resistance scheme of two fetuses connected by arterio-arterial (AA) and veno-venous (VV) anastomoses, the small VV resistance approximated as zero. The smaller twin has volume fraction α < 1 of the assumed normal larger twin, and has only access to fraction X < 1 of its placenta; the larger twin's larger mean arterial pressure accesses the remaining fraction. Before 13 weeks, embryos have a much smaller vascular resistance than placentas. After 13 weeks, when maternal blood provides oxygen, smaller twins can increase their vascular volume by hypoxemia-mediated neovascularization. Estimated AA radii at 40 weeks, rAA (40), are 0.5-1.3 mm. RESULTS Embryos with α < 0.33 unlikely survive 13 weeks and acardiac twinning occurs under appropriate conditions (AA-VV, small placenta). Acardiac body perfusion occurs because of a much smaller vascular resistance than the placenta. When α > 0.33 and rAA (40)=1.3 mm, modeled survival is >32 weeks. CONCLUSION Before 13 weeks, embryos with α < 0.33 cannot survive and may result in the onset of acardia. Beyond 13 weeks, fetuses with α ≥ 0.33 survive because rAA (40) is too small for acardiac onset. Following fetal demise, exsanguination from the live twin increases its blood volume and, we assumed also, its vascular resistance. Perfusion then occurs through the lower resistance placenta.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Michael G Ross
- Department of Obstetrics and Gynecology, Harbor UCLA Medical Center, Torrance, California, USA
| | | | - Peter G J Nikkels
- Department of Pathology, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands
| |
Collapse
|
9
|
van Gemert MJC, Nikkels PGJ, Ross MG, van den Wijngaard JPHM. Acardiac twin pregnancies part V: Why does an acardiac twin with renal tissue produce polyhydramnios? Birth Defects Res 2021; 113:500-510. [PMID: 33529493 PMCID: PMC7986173 DOI: 10.1002/bdr2.1874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 12/17/2020] [Accepted: 01/14/2021] [Indexed: 12/28/2022]
Abstract
Background Acardiac twinning is a complication of monochorionic twin pregnancies. From literature reports, 30 of 41 relatively large acardiac twins with renal tissue produced polyhydramnios within their amniotic compartment. We aim to investigate the underlying mechanisms that cause excess amniotic fluid using an established model of fetal fluid dynamics. Methods We assumed that acardiac onset is before 13 weeks, acardiacs with renal tissue have normal kidney function and produce urine flow from 11 weeks on, and acardiac urine production requires a pressure of half the pump twin's mean arterial pressure. We apply a resistance network with the pump twin's arterio‐venous pressure as source, pump umbilical arteries, placenta, placental arterio‐arterial (AA) anastomoses and acardiac resistances. Acardiac amniotic fluid dynamics excluded acardiac lung fluid secretion, swallowing and the relatively small intramembranous flow. Results In small acardiacs with sufficient urine production, polyhydramnios will occur due to the lack of amniotic fluid resorption. Urine production is dependent upon having sufficient mean arterial pressure, which requires nearly a two‐fold larger resistance within the acardiac as compared to the placental AA resistance. Subphysiologic arterial pressure may result in renal dysgenesis. Conclusion Our findings suggest the potential for prediction of which clinical acardiac cases may or may not develop polyhydramnios based upon noninvasive assessments of renal tissue, blood flow and urine production. This information would be of great value in determining early obstetric interventions as opposed to conservative management. These findings may also contribute to an improved knowledge of the fascinating pathophysiology that surrounds acardiac twinning.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Centra, Location AMC, Amsterdam, The Netherlands
| | - Peter G J Nikkels
- Department of Pathology, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands
| | - Michael G Ross
- Department of Obstetrics and Gynecology, Harbor UCLA Medical Center, Torrance, California, USA
| | | |
Collapse
|
10
|
Agnass P, van Veldhuisen E, van Gemert MJC, van der Geld CWM, van Lienden KP, van Gulik TM, Meijerink MR, Besselink MG, Kok HP, Crezee J. Mathematical modeling of the thermal effects of irreversible electroporation for in vitro, in vivo, and clinical use: a systematic review. Int J Hyperthermia 2020; 37:486-505. [DOI: 10.1080/02656736.2020.1753828] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Pierre Agnass
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
- Department of Surgery, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Eran van Veldhuisen
- Department of Surgery, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Martin J. C. van Gemert
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Cees W. M. van der Geld
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Krijn P. van Lienden
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Thomas M. van Gulik
- Department of Surgery, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Martijn R. Meijerink
- Department of Radiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Marc G. Besselink
- Department of Surgery, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - H. Petra Kok
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Johannes Crezee
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
11
|
Westerhof BE, van Gemert MJC, van den Wijngaard JP. Pressure and Flow Relations in the Systemic Arterial Tree Throughout Development From Newborn to Adult. Front Pediatr 2020; 8:251. [PMID: 32509713 PMCID: PMC7248228 DOI: 10.3389/fped.2020.00251] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/22/2020] [Indexed: 12/21/2022] Open
Abstract
Objective: Distributed models of the arterial tree allow studying the effect of physiological and pathophysiological changes in the vasculature on hemodynamics. For the adult, several models exist; however, a model encompassing the full age range from newborn to adult was until now lacking. Our goal is to describe a complete distributed hemodynamic model for normal development from newborn to adult. Methods: The arterial system was modeled by 121 segments characterized by length, radius, wall thickness, wall stiffness, and wall viscosity. The final segments ended in three-element Windkessels. All parameters were adapted based on body height and weight as a function of age as described in the literature. Results: Pressures and flows are calculated as a function of age at sites along the arterial tree. Central to peripheral transfer functions are given. Our results indicate that peripheral pressure in younger children resembles central pressure. Furthermore, total arterial compliance, inertance and impedance are calculated. Findings indicate that the arterial tree can be simulated by using a three-element Windkessel system. Pulse wave velocity in the aorta was found to increase during development. Conclusions: The arterial system, modeled from newborn to adult bears clinical significance, both for the interpretation of peripheral measured pressure in younger and older children, and for using a Windkessel model to determine flow from pressure measurements.
Collapse
Affiliation(s)
- Berend E Westerhof
- Cardiovascular and Respiratory Physiology, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, Netherlands.,Pulmonary Medicine, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Free Universiteit Amsterdam, Amsterdam, Netherlands.,Medical Biology, Section of Systems Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Martin J C van Gemert
- Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | | |
Collapse
|
12
|
van Gemert MJC, Streekstra GJ, Vandenbussche FPHA, Nikkels PGJ, van den Wijngaard JPHM. Acardius anceps with neck cyst and cleft palate: Three dimensional skeletal computed tomography reconstruction with discussion of the literature. Birth Defects Res 2019; 112:137-140. [PMID: 31774253 DOI: 10.1002/bdr2.1625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/28/2019] [Accepted: 11/12/2019] [Indexed: 11/11/2022]
Abstract
Acardiac twinning is a rare anomaly of monochorionic twin pregnancies. Acardiac fetuses lack a functional heart but are passively perfused by arterial blood from their pump co-twin causing the acardiac body to be hypoxemic. In this report, we present an acardius anceps, therapeutically laser separated from its pump twin at 16 weeks. The healthy pump twin and macerated acardiac body were born at 40 3/7 weeks. A three dimensional (3D) reconstruction was made by CT images, showing cranial bones, spinal column, pelvis and lower extremities but absent arms. A cyst in the neck of the acardiac twin was identified by postnatal sonography; this was also described in four literature cases, and was additionally observed by us in two other acardiac twins. Median cleft palate was identified by oral cavity inspection but undetectable in the reconstruction. In the literature, we found 21 other acardiac anceps twins with a cleft palate. From the two larger published series, with 12 clefts in 21 acardiac anceps twins, a cleft palate occurs in over 50% during acardiac twinning. Our first hypothesis is that acardiac fetuses develop an oral cleft palate when acardiac onset starts prior to 11 weeks, because 11 weeks includes the period of embryonic oral cavity formation, and no cleft occurs when onset starts later than 11 weeks. Our second hypothesis is that cysts and cleft palates are more common in acardiac twins than currently known, likely reflecting that acardiac bodies are hypoxemic and that hypoxia contributes to the development of both cysts and clefts.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering and Physics, Amsterdam UMC, location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Geert J Streekstra
- Department of Biomedical Engineering and Physics, Amsterdam UMC, location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Frank P H A Vandenbussche
- Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Peter G J Nikkels
- Department of Pathology, University Medical Center and Wilhelmina Children's Hospital, Utrecht, The Netherlands
| | | |
Collapse
|
13
|
van Gemert MJC, Bruijninckx CMA, Neumann HAM, Sauer PJJ, de Bruin DM, van Leeuwen TG. Weight velocity equations with 14-448 days time separated weights should not be used for infants under 3 years of age. Med Hypotheses 2019; 129:109234. [PMID: 31371083 DOI: 10.1016/j.mehy.2019.109234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/10/2019] [Accepted: 05/18/2019] [Indexed: 11/16/2022]
Abstract
Abnormal growth of infants may indicate disease of the children, thus methods to identify growth disorders are wanted in medicine. We previously showed that two-time-points weight growth velocities at age t, calculated by a commercial software product as [Weight(t) - Weight(t - X)]/X, with X = 448 days, were erroneous due to the long separation of 448 days. We were convinced that shorter X-values would solve this accuracy problem. However, our hypothesis is that: "shorter time separations than 448 days cause a decreased accuracy of numerical weight velocity equations in realistic infant weights until an age of about three years". Supporting evidence comes from analyzing how shorter X-values will affect the accuracy of two-time-points weight velocity calculations. We systematically varied X between 1 and 448 days of various P50/0SD-related standard weight curves: (a) P50/0SD with the weights separated by 1 day and X = 1,28,224,448 days; (b) P50/0SD with the weights at variable ages and X = 14-448 days; and (c) case (b) and incorporating weight fluctuations typically occurring in infants. Cases (b) and (c) include details observed in a clinical case. Our results show that the combination of weight fluctuations and varying time intervals between consecutive weights make weight velocity predictions worse for shorter X values in children younger than three years. Because these two causes of failure occur naturally in infants whose weight is regularly measured, other weight velocity equations face the same causes for inaccuracy. In conclusion, our hypothesis suggests that any software that predicts weight velocities should be abandoned in infants < 3 years. Practically, it should require that when (commercial) software weight velocity prediction suggests a medical problem, careful clinical checking should be mandatory, e.g. by linking predicted and exact weight velocities at age t (the latter from the mathematical first derivative at age t of standard weight curves).
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam UMC, Location AMC, University of Amsterdam, Amsterdam, The Netherlands.
| | | | - H A Martino Neumann
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Pieter J J Sauer
- Department of Pediatrics, University Medical Center, Groningen, The Netherlands
| | - D Martijn de Bruin
- Department of Biomedical Engineering & Physics, Amsterdam UMC, Location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ton G van Leeuwen
- Department of Biomedical Engineering & Physics, Amsterdam UMC, Location AMC, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
14
|
Wohlmuth C, Bergh E, Bell C, Johnson A, Moise KJ, van Gemert MJC, van den Wijngaard JPHM, Wohlmuth-Wieser I, Averiss I, Gardiner HM. Clinical Monitoring of Sacrococcygeal Teratoma. Fetal Diagn Ther 2019; 46:333-340. [PMID: 30893693 DOI: 10.1159/000496841] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/09/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND Sacrococcygeal teratomas (SCT) are often highly vascularized and may result in high-output cardiac failure, polyhydramnios, fetal hydrops, and demise. Delivery is guided by the SCT to fetus volume ratio (SCTratio), SCT growth rate, and cardiac output indexed for weight (CCOi). METHODS We compared measurements and outcome in 12 consecutive fetuses referred with SCT. Adverse outcomes were: fetal surgery, delivery < 32 gestational weeks or neonatal demise. Only SCTratio and CCOi were used to manage the cases. SCT vascularization index (VI%) was derived from the 3D virtual organ computer-aided analysis (VOCAL) software. The SCTModel (modified from acardiac twins) calculated a hypothetical SCT draining vein size and derived a risk line, using diameters of the superior and inferior vena cava, the azygous and umbilical veins. VI% and a model of systemic and umbilical venous volumes (SCTModel) were tested as indicators for outcome in SCT. RESULTS Fetuses were monitored from 20.1 to 36.4 gestational weeks and 5/12 had adverse outcomes: 1 had successful open fetal surgery at 23.8 weeks and delivered at term, 4 delivered at < 32 weeks with 3/4 having neonatal demise between 25 and 29 weeks. VI% was significantly higher in cases with adverse outcomes (mean 10.3 [8.9-11.6] vs. 4.4 [3.4-5.3], p < 0.0001). The additional fraction of the fetal cardiac output required to perfuse the SCT-draining vein (XSCO%) (p = 0.46), SCTratio (p = 0.08), and CCOi (p = 0.64) were not significant. All cases with adverse outcome had VI% > 8%. The SCTModel risk line predicted nonadverse outcomes well but lacked data in 2/5 cases with adverse outcomes. CONCLUSIONS VI% is a significant indicator of SCT cases with adverse outcomes and combined with SCTratio may guide timing of delivery better than current measures.
Collapse
Affiliation(s)
- Christoph Wohlmuth
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA, .,Department of Obstetrics and Gynecology, Paracelsus Medical University Salzburg, Salzburg, Austria,
| | - Eric Bergh
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA.,Department of Obstetrics, Gynecology and Reproductive Science, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Cynthia Bell
- McGovern Medical School at UTHealth, Center for Clinical Research and Evidence-Based Medicine, Houston, Texas, USA
| | - Anthony Johnson
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA
| | - Kenneth J Moise
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA
| | - Martin J C van Gemert
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeroen P H M van den Wijngaard
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Iris Wohlmuth-Wieser
- Department of Dermatology, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Ian Averiss
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA
| | - Helena M Gardiner
- The Fetal Center, Children's Memorial Hermann Hospital and the Department of Obstetrics and Gynecology, McGovern Medical School, UTHealth, Houston, Texas, USA
| |
Collapse
|
15
|
van Gemert MJC, Bruijninckx CMA, van Leeuwen TG, Neumann HAM, Sauer PJJ. Limitations of Weight Velocity Analysis by Commercial Computer Program Growth Analyser Viewer Edition. Ann Biomed Eng 2018; 47:297-305. [PMID: 30151732 PMCID: PMC6315011 DOI: 10.1007/s10439-018-02118-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/16/2018] [Indexed: 11/22/2022]
Abstract
Commercial software package “Growth Analyser Viewer Edition” (“GAVE”) aims to document, monitor and analyze growth and development in children and adolescents. Although its clinical and scientific use is widespread, there are no published studies that describe the method and its validation. We were informed that GAVE calculates the weight velocity (kg/year) at age t from the weight difference between t and 448 days earlier or at birth, divided by the time difference. We recently discussed a case of false child abuse diagnosis (Pediatric Condition Falsification), resulting in the separation of the child from its parents, in which GAVE played a negative contributing role. To prevent such inappropriate diagnoses, we analyzed GAVE from a schematic representation of the measured clinical weight curve, with precisely defined weight velocities. In conclusion, the 448 days included for weight velocity predictions by GAVE caused the erroneous outcomes. Until the necessary changes to the software are implemented and validated, we advise against the use of GAVE in infants younger than 1.5 years, if multiple weight changes occur within 448 days, and following a long-lasting weight velocity change. Our analysis suggests to discard all medical software packages that lack public description and proof of validation.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | | | - Ton G van Leeuwen
- Department of Biomedical Engineering & Physics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - H A Martino Neumann
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Pieter J J Sauer
- Department of Pediatrics, University Medical Center, Groningen, The Netherlands
| |
Collapse
|
16
|
van Gemert MJC, Vlaming M, Osinga E, Bruijninckx CMA, Neumann HAM, Sauer PJJ. Pediatric Condition Falsification Misdiagnosed by Misjudged Weight Growth from the Curve of Measured Weights. Am J Case Rep 2018; 19:752-756. [PMID: 29946058 PMCID: PMC6053948 DOI: 10.12659/ajcr.908770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patient: Male, 0–2 Final Diagnosis: Cow milk allergy Symptoms: Obstipation • airway infections Medication: — Clinical Procedure: Elementary feeding Specialty: Pediatrics
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Marianne Vlaming
- Private Practice, Criminal Psychology and Law, Doetinchem, Netherlands
| | - Eric Osinga
- Private Practice, Osinga Advocatuur (Law Office), Utrecht, Netherlands
| | | | | | - Pieter J J Sauer
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen, Groningen, Netherlands
| |
Collapse
|
17
|
van Gemert MJC, Bloemen PR, Wang WY, van der Geld CWM, Nuijts RMMA, Hortoglu H, Wolkerstorfer A, de Bruin DM, van Leeuwen TG, Neumann HAM, Jager MJ. Periocular CO2
laser resurfacing: severe ocular complications from multiple unintentional laser impacts on the protective metal eye shields. Lasers Surg Med 2018; 50:980-986. [DOI: 10.1002/lsm.22951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Martin J. C. van Gemert
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Paul R. Bloemen
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Wei-Yong Wang
- Department of Ophthalmology; Leiden University Medical Center; Leiden The Netherlands
| | | | - Rudy M. M. A. Nuijts
- Department of Ophthalmology; Maastricht University Medical Center; Maastricht The Netherlands
| | | | - Albert Wolkerstorfer
- Department of Dermatology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Daniel M. de Bruin
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Ton G. van Leeuwen
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | | | - Martine J. Jager
- Department of Ophthalmology; Leiden University Medical Center; Leiden The Netherlands
| |
Collapse
|
18
|
Gemert MJCV, Wijngaard JPHMVD, Paarlberg KM, Gardiner HM, Nikkels PGJ. Acardiac twin pregnancies part IV: Acardiac onset from unequal embryonic splitting simulated by a fetoplacental resistance model. Birth Defects Res 2018; 109:211-223. [PMID: 27891739 DOI: 10.1002/bdra.23581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/16/2016] [Accepted: 09/20/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Benirschke postulated that acardiac twinning occurs when markedly unequal embryonic splitting combines with arterioarterial (AA) and venovenous placental anastomoses. We tested this hypothesis by model simulations and by comparison of outcomes with 18 "pseudo-" (twin fetus with beating heart but otherwise with clear signs of an acardiac) and 3 "normal" acardiac cases. METHODS The smaller/larger cell volume ratio at embryonic splitting becomes the smaller/larger embryonic/fetal blood volume ratio (a). From a, we derived nonpulsating blood pressures using normal values (larger twin) and normal values at an appropriate earlier gestational age (smaller twin). These unequal pressure sources were used in a linear resistance fetoplacental network to calculate umbilical venous diameter ratios. Acardiac onset occurs when the smaller twin has 50% left of its normal, singleton placenta. Comparison with clinical cases approximated a by crown-rump-length-ratio to the 3rd power. Input parameters are a and the AA-radius at 40 weeks. RESULTS Acardiacs can be small or large, can occur early or late, earlier at smaller a and larger AA, with larger umbilical venous diameter ratios at smaller a and smaller AA. Comparison with the 21 clinical cases was good, except for 2. CONCLUSION Our analysis supports Benirschke's hypothesis. The smaller twin has to share its placental perfusion with the larger twin, which is a novel finding. The AA size is essential for the future of both fetuses but complicates easy understanding of (pseudo-)acardiac clinical presentations. Late acardiac onset occurs infrequently. Using nonpulsating circulations may have caused our extensive predictions of late onset. An improved model requires including hypoxemia in the smaller twin from chronic placental hypoperfusion. Birth Defects Research 109:211-223, 2017. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeroen P H M van den Wijngaard
- Department of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - K Marieke Paarlberg
- Department of Obstetrics and Gynecology, Gelre Hospitals, location Apeldoorn, The Netherlands
| | - Helena M Gardiner
- The Fetal Center, McGovern Medical School at UTHealth, University of Texas, Houston, TX, USA
| | - Peter G J Nikkels
- Department of Pathology, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands
| |
Collapse
|
19
|
Heger M, Beek JF, Moldovan NI, van der Horst CMAM, van Gemert MJC. Towards optimization of selective photothermolysis: prothrombotic pharmaceutical agents as potential adjuvants in laser treatment of port wine stains. Thromb Haemost 2017; 93:242-56. [PMID: 15711739 DOI: 10.1160/th04-05-0291] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SummaryFor the past two decades much research on selective photothermolysis of port wine stain vasculature has been devoted to optimizing laser parameters. Unfortunately, 60% of patients still respond suboptimally to laser therapy, despite significant innovations in treatment strategies and laser technology. Here we present a novel treatment approach based on combining selective photothermolysis with the administration of prothrombotic and/or anti-fibrinolytic pharmaceutical agents, with the aim of enhancing vaso-occlusion and post-treatment remodelling in difficult-to-target vessels. A hypercoagulable state of blood will instill laser-induced occlusive thrombosis in a wider array of vessel diameters at greater dermal depths, whereby larger vascular segments will ultimately undergo the chronic inflammatory processes that result in blood volume reduction, and thus lesional blanching. With thrombosis as a primary trigger for these inflammatory processes, we have extrapolated the thresh-old damage profile that is required for clinically relevant thrombus formation. Consequently, a recently proposed model of thrombus organization, in which recanalization is associated with endothelial progenitor cell-mediated neovasculogenesis, is elaborated in the framework of lesional blanching and juxtaposed to angiogenic reconstruction of affected dermal vasculature. Since neovasculogenesis and angiogenesis are regulated by the degree of vaso-occlusion and corollary drop in local oxygen tension, both can be manipulated by the administration of procoagulant pharmaceuticals. Lastly, in an effort to optimally balance selective photothermolysis with pharmacokinetics and clinical safety, the use of a gold nanoshell drug delivery system, in which the procoagulant drugs are encapsulated by a wavelength-modulated, gold-coated polymer matrix, is proposed. We have termed this modality site-specific pharmaco-laser therapy.
Collapse
Affiliation(s)
- Michal Heger
- Laser Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
20
|
de Bruin DM, Broekgaarden M, van Gemert MJC, Heger M, de la Rosette JJ, Van Leeuwen TG, Faber DJ. Assesment of apoptosis induced changes in scattering using optical coherence tomography. J Biophotonics 2016; 9:913-923. [PMID: 26564260 DOI: 10.1002/jbio.201500198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/28/2015] [Accepted: 10/18/2015] [Indexed: 06/05/2023]
Abstract
The aim of this study is to identify changes in scattering with optical coherence tomography (OCT) and relate these measurements with mitochondrial changes during the initiation of apoptosis. Human retinal pigment epithelial cells were cultured and apoptosis was induced using 10% alcohol. Using the attenuation coefficient and backscattering, changes were measured during cell death in a cell-pellet and monolayer respectively. To confirm apoptosis, fluorescent activated cell sorting was used. Mitochondrial activity during apoptosis was assessed using an oxidative stress assay and fluorescent confocal microscopy. Pelleted apoptotic cells measured with OCT showed a clear rise while untreated cells showed a very small increase in attenuation coefficient. Monolayered apoptotic cells displayed a distinct increase, while untreated cells showed a small increase in the backscattering. Apoptosis was confirmed by FACS experiments. Mitochondrial changes during the onset of apoptosis were also measured. The results demonstrate that apoptotic cell death could be monitored in real-time by OCT. Changes in the scattering after induction of apoptosis are likely to be related to changes in the intracellular morphology. Oxidative stress-induced mitochondrial swelling could be responsible for the initial increase, while cell blebbing and secondary necrosis subsequently for the observed decrease in scattering.
Collapse
Affiliation(s)
- Daniel M de Bruin
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands.
- Urology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands.
| | - Mans Broekgaarden
- Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Martin J C van Gemert
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Michal Heger
- Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Jean J de la Rosette
- Urology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Ton G Van Leeuwen
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Dirk J Faber
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| |
Collapse
|
21
|
Scheffer HJ, Vogel JA, van den Bos W, Neal RE, van Lienden KP, Besselink MGH, van Gemert MJC, van der Geld CWM, Meijerink MR, Klaessens JH, Verdaasdonk RM. The Influence of a Metal Stent on the Distribution of Thermal Energy during Irreversible Electroporation. PLoS One 2016; 11:e0148457. [PMID: 26844550 PMCID: PMC4742246 DOI: 10.1371/journal.pone.0148457] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/18/2016] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Irreversible electroporation (IRE) uses short duration, high-voltage electrical pulses to induce cell death via nanoscale defects resulting from altered transmembrane potential. The technique is gaining interest for ablations in unresectable pancreatic and hepatobiliary cancer. Metal stents are often used for palliative biliary drainage in these patients, but are currently seen as an absolute contraindication for IRE due to the perceived risk of direct heating of the metal and its surroundings. This study investigates the thermal and tissue viability changes due to a metal stent during IRE. METHODS IRE was performed in a homogeneous tissue model (polyacrylamide gel), without and with a metal stent placed perpendicular and parallel to the electrodes, delivering 90 and 270 pulses (15-35 A, 90 μsec, 1.5 cm active tip exposure, 1.5 cm interelectrode distance, 1000-1500 V/cm, 90 pulses/min), and in-vivo in a porcine liver (4 ablations). Temperature changes were measured with an infrared thermal camera and with fiber-optic probes. Tissue viability after in-vivo IRE was investigated macroscopically using 5-triphenyltetrazolium chloride (TTC) vitality staining. RESULTS In the gel, direct stent-heating was not observed. Contrarily, the presence of a stent between the electrodes caused a higher increase in median temperature near the electrodes (23.2 vs 13.3°C [90 pulses]; p = 0.021, and 33.1 vs 24.8°C [270 pulses]; p = 0.242). In-vivo, no temperature difference was observed for ablations with and without a stent. Tissue examination showed white coagulation 1mm around the electrodes only. A rim of vital tissue remained around the stent, whereas ablation without stent resulted in complete tissue avitality. CONCLUSION IRE in the vicinity of a metal stent does not cause notable direct heating of the metal, but results in higher temperatures around the electrodes and remnant viable tissue. Future studies should determine for which clinical indications IRE in the presence of metal stents is safe and effective.
Collapse
Affiliation(s)
- Hester J. Scheffer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Jantien A. Vogel
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands
| | | | - Robert E. Neal
- Department of Radiology, The Alfred Hospital, Melbourne, Australia
| | | | | | - Martin J. C. van Gemert
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Cees W. M. van der Geld
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Martijn R. Meijerink
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - John H. Klaessens
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| | - Rudolf M. Verdaasdonk
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
22
|
van Gemert MJC, Wagstaff PGK, de Bruin DM, van Leeuwen TG, van der Wal AC, Heger M, van der Geld CWM. Irreversible electroporation: just another form of thermal therapy? Prostate 2015; 75:332-5. [PMID: 25327875 PMCID: PMC4305196 DOI: 10.1002/pros.22913] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/29/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Irreversible electroporation (IRE) is (virtually) always called non-thermal despite many reports showing that significant Joule heating occurs. Our first aim is to validate with mathematical simulations that IRE as currently practiced has a non-negligible thermal response. Our second aim is to present a method that allows simple temperature estimation to aid IRE treatment planning. METHODS We derived an approximate analytical solution of the bio-heat equation for multiple 2-needle IRE pulses in an electrically conducting medium, with and without a blood vessel, and incorporated published observations that an electric pulse increases the medium's electric conductance. RESULTS IRE simulation in prostate-resembling tissue shows thermal lesions with 67-92°C temperatures, which match the positions of the coagulative necrotic lesions seen in an experimental study. Simulation of IRE around a blood vessel when blood flow removes the heated blood between pulses confirms clinical observations that the perivascular tissue is thermally injured without affecting vascular patency. CONCLUSIONS The demonstration that significant Joule heating surrounds current multiple-pulsed IRE practice may contribute to future in-depth discussions on this thermal issue. This is an important subject because it has long been under-exposed in literature. Its awareness pleads for preventing IRE from calling "non-thermal" in future publications, in order to provide IRE-users with the most accurate information possible. The prospect of thermal treatment planning as outlined in this paper likely aids to the important further successful dissemination of IRE in interventional medicine. Prostate 75:332-335, 2015. © 2014 The Authors. The Prostate Published by Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Martin J C van Gemert
- Department of Biomedical Engineering & Physics, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
- Correspondence to: Prof. Martin J. C. van Gemert, PhD, Department of Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, The Netherlands. E-mail:
| | - Peter G K Wagstaff
- Department of Urology, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
| | - Daniel M de Bruin
- Department of Biomedical Engineering & Physics, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
- Department of Urology, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
| | - Ton G van Leeuwen
- Department of Biomedical Engineering & Physics, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
| | - Allard C van der Wal
- Department of Pathology, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
| | - Michal Heger
- Department of Experimental Surgery, Academic Medical Center, University of AmsterdamAmsterdam, The Netherlands
| | - Cees W M van der Geld
- Department of Mechanical Engineering, Eindhoven University of TechnologyEindhoven, The Netherlands
| |
Collapse
|
23
|
Abstract
Physicists and medical doctors "speak" different languages. Endovenous laser ablation (EVLA) is a good example in which technology is essential to guide the doctor to the final result: optimal treatment. However, for the doctor, it is by far insufficient just to turn on the knobs of the laser. He should understand what is going on in the varicose vein. On the other hand, the physicist is usually not aware what problems the doctor finds on his road towards improving a new technique. We have tried to bring both languages together in the special on Ins and outs of endovenous laser ablation published in this issue of Lasers in Medical Science. The 13 articles include endovenous related clinical (de Roos 2014; Kockaert and Nijsten 2014; van den Bos and Proebstle 2014) and socioeconomical articles (Kelleher et al 2014), the first paper on the molecular pathophysiologic mechanisms (Heger et al 2014), fiber tips (Stokbroekx et al 2014), the future of EVLA (Rabe 2014), a review of EVLA with some important issues for debate (Malskat et al 2014), an excellent paper on transcutaneous laser therapies of spider and small varicose veins (Meesters et al 2014), as well as several scientific modeling articles, varying from a mathematical model of EVLA that includes the carbonized blood layer on the fiber tip (van Ruijven et al 2014) and its application to the simulation of clinical conditions (Poluektova et al 2014) via experimental measurements of temperature profiles in response to EVLA, radiofrequency waves, and steam injections (Malskat et al 2014) to a literature review and novel physics approach of the absorption and particularly scattering properties of whole blood also including the infrared wavelengths used by EVLA (Bosschaart et al 2014). The aim of our afterthoughts, the 14th article in this special, is to try to amalgamate the clinical and physical contents of these contributions, providing the reader with the bridge that overlaps these different backgrounds.
Collapse
Affiliation(s)
- H. A. Martino Neumann
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Martin J. C. van Gemert
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
24
|
Neumann HAM, van Gemert MJC. Introduction to ins and outs of endovenous laser ablation by the associate guest editors. Lasers Med Sci 2013; 29:375-6. [PMID: 24366292 DOI: 10.1007/s10103-013-1495-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 11/10/2013] [Indexed: 11/27/2022]
Affiliation(s)
- H A Martino Neumann
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | |
Collapse
|
25
|
Malskat WSJ, Poluektova AA, van der Geld CWM, Neumann HAM, Weiss RA, Bruijninckx CMA, van Gemert MJC. Endovenous laser ablation (EVLA): a review of mechanisms, modeling outcomes, and issues for debate. Lasers Med Sci 2013; 29:393-403. [PMID: 24366291 PMCID: PMC3953603 DOI: 10.1007/s10103-013-1480-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/22/2013] [Indexed: 11/30/2022]
Abstract
Endovenous laser ablation (EVLA) is a commonly used and very effective minimally invasive therapy to manage leg varicosities. Yet, and despite a clinical history of 16 years, no international consensus on a best treatment protocol has been reached so far. Evidence presented in this paper supports the opinion that insufficient knowledge of the underlying physics amongst frequent users could explain this shortcoming. In this review, we will examine the possible modes of action of EVLA, hoping that better understanding of EVLA-related physics stimulates critical appraisal of claims made concerning the efficacy of EVLA devices, and may advance identifying a best possible treatment protocol. Finally, physical arguments are presented to debate on long-standing, but often unfounded, clinical opinions and habits. This includes issues such as (1) the importance of laser power versus the lack of clinical relevance of laser energy (Joule) as used in Joule per centimeter vein length, i.e., in linear endovenous energy density (LEED), and Joule per square centimeter vein wall area, (2) the predicted effectiveness of a higher power and faster pullback velocity, (3) the irrelevance of whether laser light is absorbed by hemoglobin or water, and (4) the effectiveness of reducing the vein diameter during EVLA therapy.
Collapse
Affiliation(s)
- Wendy S J Malskat
- Department of Dermatology, Erasmus Medical Center, Burgemeester's Jacobplein 51, 3015 CA, Rotterdam, The Netherlands,
| | | | | | | | | | | | | |
Collapse
|
26
|
Heger M, van Golen RF, Broekgaarden M, van den Bos RR, Neumann HAM, van Gulik TM, van Gemert MJC. Endovascular laser–tissue interactions and biological responses in relation to endovenous laser therapy. Lasers Med Sci 2013; 29:405-22. [DOI: 10.1007/s10103-013-1490-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 11/03/2013] [Indexed: 01/11/2023]
|
27
|
Bremmer RH, van Gemert MJC, Faber DJ, van Leeuwen TG, Aalders MCG. Diffuse reflectance relations based on diffusion dipole theory for large absorption and reduced scattering. J Biomed Opt 2013; 18:87007. [PMID: 23986392 DOI: 10.1117/1.jbo.18.8.087007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Diffuse reflectance spectra are used to determine the optical properties of biological samples. In medicine and forensic science, the turbid objects under study often possess large absorption and/or scattering properties. However, data analysis is frequently based on the diffusion approximation to the radiative transfer equation, implying that it is limited to tissues where the reduced scattering coefficient dominates over the absorption coefficient. Nevertheless, up to absorption coefficients of 20 mm-1 at reduced scattering coefficients of 1 and 11.5 mm-1, we observed excellent agreement (r2=0.994) between reflectance measurements of phantoms and the diffuse reflectance equation proposed by Zonios et al. [Appl. Opt.38, 6628-6637 (1999)], derived as an approximation to one of the diffusion dipole equations of Farrell et al. [Med. Phys.19, 879-888 (1992)]. However, two parameters were fitted to all phantom experiments, including strongly absorbing samples, implying that the reflectance equation differs from diffusion theory. Yet, the exact diffusion dipole approximation at high reduced scattering and absorption also showed agreement with the phantom measurements. The mathematical structure of the diffuse reflectance relation used, derived by Zonios et al. [Appl. Opt.38, 6628-6637 (1999)], explains this observation. In conclusion, diffuse reflectance relations derived as an approximation to the diffusion dipole theory of Farrell et al. can analyze reflectance ratios accurately, even for much larger absorption than reduced scattering coefficients. This allows calibration of fiber-probe set-ups so that the object's diffuse reflectance can be related to its absorption even when large. These findings will greatly expand the application of diffuse reflection spectroscopy. In medicine, it may allow the use of blue/green wavelengths and measurements on whole blood, and in forensic science, it may allow inclusion of objects such as blood stains and cloth at crime scenes.
Collapse
Affiliation(s)
- Rolf H Bremmer
- University of Amsterdam, Academic Medical Center, Department of Biomedical Engineering and Physics, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
28
|
van Gemert MJC, van der Geld CWM, Bruijninckx CMA, Verdaasdonk RM, Neumann HAM. Comment to Vuylsteke ME and Mordon SR. Endovenous laser ablation: a review of mechanisms of action. Ann Vasc Surg 2012;26:424-33. Ann Vasc Surg 2012; 26:881-3. [PMID: 22794335 DOI: 10.1016/j.avsg.2012.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 04/24/2012] [Indexed: 11/16/2022]
|
29
|
Stam B, Gemert MJCV, Leeuwen TGV, Aalders MCG. How the blood pool properties at onset affect the temporal behavior of simulated bruises. Med Biol Eng Comput 2012; 50:165-71. [PMID: 22261914 PMCID: PMC3272227 DOI: 10.1007/s11517-012-0860-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 01/05/2012] [Indexed: 11/27/2022]
Abstract
The influence of initial blood pool properties on the temporal behavior of bruises is currently unknown. We addressed this important issue by utilizing three typical classes of bruises in our three-layered finite compartment model. We simulated the effects of their initial shapes, regularity of boundaries and initial blood concentration distributions (gaussian vs. homogeneous) on the hemoglobin and bilirubin areas in the dermal top layer. Age determination of bruises with gaussian hemoglobin concentration was also addressed. We found that the initial blood pool properties strongly affect bruise behavior. We determined the age of a 200-h simulated bruise with gaussian hemoglobin concentration with 3 h uncertainty. In conclusion, bruise behavior depends non-intuitively on the initial blood pool properties; hence, a model that includes shape, area and concentration distribution at onset is indispensable. Future age determination, including inhomogeneous hemoglobin distributions, will likely be based on the presented method for gaussian distributions.
Collapse
Affiliation(s)
- Barbara Stam
- Biomedical Engineering and Physics, Academic Medical Centre, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands.
| | | | | | | |
Collapse
|
30
|
Stam B, van Gemert MJC, van Leeuwen TG, Teeuw AH, van der Wal AC, Aalders MCG. Can color inhomogeneity of bruises be used to establish their age? J Biophotonics 2011; 4:759-67. [PMID: 21595043 DOI: 10.1002/jbio.201100021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/29/2011] [Accepted: 05/07/2011] [Indexed: 05/11/2023]
Abstract
Bruises become spatially inhomogeneous during the healing process; a smaller red-blue core area, caused by hemoglobin, is surrounded by a larger yellow area, caused by bilirubin, which is enzymatically formed from hemoglobin. These two areas develop at different rates and hence carry information about the age of the bruise. We present a proof of principle demonstration that the age of bruises can be determined via an inverse procedure using a mathematical model and daily measurements of these two areas using a hyperspectral imaging system. The inaccuracy found is 2.3% for fresh bruises and 3 to 24% for bruises up to 3 days old. In conclusion, color inhomogeneity of bruises can be used to determine their age. We expect that future age determination of bruises by the inverse procedure described here, possibly also including the distribution of concentrations in the areas will open up a new phase in clinical bruise classification.
Collapse
Affiliation(s)
- Barbara Stam
- Department of Biomedical Engineering and Physics, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
| | | | | | | | | | | |
Collapse
|
31
|
van der Geld CWM, van den Bos RR, van Ruijven PWM, Nijsten T, Neumann HAM, van Gemert MJC. The heat-pipe resembling action of boiling bubbles in endovenous laser ablation. Lasers Med Sci 2010; 25:907-9. [PMID: 20644976 PMCID: PMC2935543 DOI: 10.1007/s10103-010-0780-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Accepted: 03/15/2010] [Indexed: 11/30/2022]
Abstract
Endovenous laser ablation (EVLA) produces boiling bubbles emerging from pores within the hot fiber tip and traveling over a distal length of about 20 mm before condensing. This evaporation-condensation mechanism makes the vein act like a heat pipe, where very efficient heat transport maintains a constant temperature, the saturation temperature of 100°C, over the volume where these non-condensing bubbles exist. During EVLA the above-mentioned observations indicate that a venous cylindrical volume with a length of about 20 mm is kept at 100°C. Pullback velocities of a few mm/s then cause at least the upper part of the treated vein wall to remain close to 100°C for a time sufficient to cause irreversible injury. In conclusion, we propose that the mechanism of action of boiling bubbles during EVLA is an efficient heat-pipe resembling way of heating of the vein wall.
Collapse
Affiliation(s)
- Cees W. M. van der Geld
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Renate R. van den Bos
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Peter W. M. van Ruijven
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Tamar Nijsten
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - H. A. Martino Neumann
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Martin J. C. van Gemert
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
32
|
Bosschaart N, Aalders MCG, Faber DJ, Weda JJA, van Gemert MJC, van Leeuwen TG. Quantitative measurements of absorption spectra in scattering media by low-coherence spectroscopy. Opt Lett 2009; 34:3746-8. [PMID: 19953182 DOI: 10.1364/ol.34.003746] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Low-coherence spectroscopy (LCS) is a spectroscopic method that allows for quantitative and localized assessment of absorption spectra by combining reflection spectroscopy with low-coherence interferometry. We describe absorption coefficient (mu(a)) measurements by LCS in tissue simulating phantoms with varying scattering and absorbing properties. We used LCS in the 455-680 nm wavelength range with a spectral resolution of 8 nm to obtain mu(a) spectra with +/-0.5 mm(-1) accuracy. We conclude that LCS is a promising technique for the in vivo determination of tissue chromophore concentrations.
Collapse
Affiliation(s)
- Nienke Bosschaart
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, P.O. Box 22700,NL-1100 DE Amsterdam, The Netherlands.
| | | | | | | | | | | |
Collapse
|
33
|
van den Bos RR, Kockaert MA, Martino Neumann HA, Bremmer RH, Nijsten T, van Gemert MJC. Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins. Lasers Med Sci 2009. [DOI: 10.1007/s10103-009-0668-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
34
|
van den Bos RR, Kockaert MA, Martino Neumann HA, Bremmer RH, Nijsten T, van Gemert MJC. Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins. Lasers Med Sci 2009; 24:247-51. [DOI: 10.1007/s10103-008-0639-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 12/23/2008] [Indexed: 11/29/2022]
|
35
|
Lopriore E, Oepkes D, van den Wijngaard JPHM, van Gemert MJC, Middeldorp JM, Vandenbussche FPHA. Twin anemia-polycythemia sequence (TAPS) without a cause. Prenat Diagn 2008; 28:559-60. [PMID: 18509864 DOI: 10.1002/pd.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
36
|
van Gemert MJC, Pasman SA, van den Wijngaard JPHM, Lopriore E, Vandenbussche FPHA. Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Nonlinear decay of adult red blood cells. Phys Med Biol 2008; 53:L11-4. [PMID: 18560048 DOI: 10.1088/0031-9155/53/13/l01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recently, we derived equations relating the flow of adult red blood cells through a placental arterio-venous anastomosis with intra-uterine and post-natal measured adult hemoglobin concentrations. In this letter, we re-derived the equations, now including a more realistic nonlinear decay of adult red blood cells, and re-evaluated the measurement accuracy of the arterio-venous flow and the lifetime of the red blood cells.
Collapse
|
37
|
van Gemert MJC, van den Wijngaard JPHM, Lopriore E, Pasman SA, Vandenbussche FPHA. Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Phys Med Biol 2008; 53:N109-17. [DOI: 10.1088/0031-9155/53/7/n02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
38
|
van den Wijngaard JPHM, Ross MG, van Gemert MJC. Thrombosis of anastomoses may affect the staging sequence of twin–twin transfusion syndrome. Phys Med Biol 2008; 53:N69-80. [DOI: 10.1088/0031-9155/53/5/n02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
39
|
van den Wijngaard JPHM, Umur A, Ross MG, van Gemert MJC. Twin–twin transfusion syndrome: mathematical modelling. Prenat Diagn 2008; 28:280-91. [DOI: 10.1002/pd.1944] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
40
|
van der Ploeg-Westerveld J, Wagter J, van Gemert MJC, Neumann HAM, Bour H, Zwart A. Diode laser hair removal around ileo-colo ostomys is safe, effective and beneficial: a pilot study. Lasers Surg Med 2007; 39:773-5. [PMID: 18081148 DOI: 10.1002/lsm.20580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVE Hair removal around an ileo-colo ostomy can cause a number of problems. We compared laser hair removal with mechanical shaving around the ostomy. METHOD Eleven patients were selected with hairy skin around the ostomy for therapy with an AlGaAs diode laser at 800 nm. Three to four treatments were given with an interval of 6 weeks. RESULTS Ten patients completed laser therapy. The average hair reduction was 60% based on visual inspection. Shaving frequency reduced from once a week to once every 6 weeks. CONCLUSIONS Laser hair removal likely becomes the preferred method in ostomy patients.
Collapse
|
41
|
van den Wijngaard JPHM, Lewi L, Lopriore E, Robyr R, Middeldorp JM, Vandenbussche FPHA, Devlieger R, Deprest J, Ville Y, van Gemert MJC. Modeling Severely Discordant Hematocrits and Normal Amniotic Fluids After Incomplete Laser Therapy in Twin-To-Twin Transfusion Syndrome. Placenta 2007; 28:611-5. [PMID: 17098282 DOI: 10.1016/j.placenta.2006.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 09/21/2006] [Accepted: 10/01/2006] [Indexed: 11/28/2022]
Abstract
Our objective was to explain the clinical presentations of sustained arteriovenous anastomotic transfusion of blood after incomplete laser therapy in twin-to-twin transfusion syndrome (TTTS). We extended our mathematical model of TTTS by adding the dynamics of hematocrit, and simulated incomplete laser therapy, first, by leaving one patent opposite arteriovenous anastomosis from the recipient to the donor and, second, by leaving one patent arteriovenous anastomosis from the donor to the recipient. In both simulations we reproduced the clinical observation of severe hematocrit discordance preceding delayed amniotic fluid imbalance. In conclusion, incomplete laser therapy may cause a severe circulatory imbalance between the twins which presents predominantly as discordant hematocrits rather than discordant amniotic fluid volumes as in primary TTTS. These results imply that the anemia-polycythemia sequence is a sensitive mechanism to identify transfusion reversal after complicated laser therapy, confirming the suggested role of middle cerebral artery peak systolic velocity Doppler measurements as a useful method of follow-up.
Collapse
Affiliation(s)
- Jeroen P H M van den Wijngaard
- Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
van den Wijngaard JPHM, Westerhof BE, Ross MG, van Gemert MJC. A mathematical model of twin-twin transfusion syndrome with pulsatile arterial circulations. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1519-31. [PMID: 17158266 DOI: 10.1152/ajpregu.00534.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The twin-twin transfusion syndrome (TTTS) is a severe complication of monochorionic twin pregnancies caused by a net transfusion of blood from one twin (the donor) to the other (the recipient) through placental anastomoses. To examine the pathophysiology of TTTS evolving through clinical stages I to IV, we extended our mathematical model to include pulsating circulations propagating along the arterial tree as well as placental and cerebral vascular resistances, and arterial wall thickness and stiffness. The model demonstrates that abnormal umbilical arterial flow (TTTS stage III) in the donor twin results from increased placental resistance as well as reduced resistance in the cerebral arteries. In contrast, recipient twin abnormal umbilical arterial flow requires a significantly greater increase in placental resistance, resulting from the compressive effects of high amniotic fluid pressure. Thus simulated abnormalities of donor umbilical arterial pulsations occur in the donor more commonly and earlier than in the recipient. The “normal” staging sequence (I, II, III, IV) correlates with the presence of compensating placental anastomoses, constituting the majority of monochorionic twin placentas. However, TTTS stage III may occur before manifestations of stage II (lack of donor bladder filling), in our model correlating with severe TTTS from a single arteriovenous anastomosis, an infrequent occurring placental angioarchitecture. In conclusion, this mathematical model describes the onset and development of the four stages of TTTS, reproduces a variety of clinical manifestations, and may contribute to identifying the underlying pathophysiology of the staging sequence in TTTS.
Collapse
|
43
|
Huikeshoven M, Koster PHL, de Borgie CAJM, Beek JF, van Gemert MJC, van der Horst CMAM. Redarkening of port-wine stains 10 years after pulsed-dye-laser treatment. N Engl J Med 2007; 356:1235-40. [PMID: 17377161 DOI: 10.1056/nejmoa064329] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Although pulsed-dye-laser therapy is currently the gold standard for the treatment of port-wine stains, few objective data are available on its long-term efficacy. Using objective color measurements, we performed a 10-year follow-up of a previously conducted prospective clinical study of the treatment of port-wine stains with a pulsed-dye laser. METHODS We invited the patients to undergo repeated color measurements performed by the same procedures as in the previous study. The results at long-term follow-up were compared with color measurements obtained before treatment and after completion of an average of five laser treatments of the complete port-wine stain. A questionnaire was used to investigate patients' satisfaction with the treatment and their perception of long-term changes in the stain. RESULTS Of the 89 patients from whom color measurements were obtained in the previous study, 51 were included in this study. The patients had received a median of seven additional treatment sessions since the last color measurement, which had been made after an average of five treatments. The median length of follow-up was 9.5 years. On average, the stain when measured at follow-up was significantly darker than it was when measured after the last of the initial five laser treatments (P=0.001), but it was still significantly lighter than it was when measured before treatment (P<0.001). Fifty-nine percent of patients were satisfied with the overall treatment result. Six percent of patients reported that the stain had become lighter since their last treatment, 59% that it was unchanged, and 35% that it had become darker. CONCLUSIONS Using objective color measurements, we observed significant redarkening of port-wine stains at long-term follow-up after pulsed-dye-laser therapy. Patients should be informed about the possibility of redarkening before beginning treatment.
Collapse
Affiliation(s)
- Menno Huikeshoven
- Department of Plastic, Reconstructive, and Hand Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | | | | | | | | | | |
Collapse
|
44
|
van den Wijngaard JPHM, Lopriore E, van der Salm SMA, Schaap AHP, Vandenbussche FPHA, Deruiter MC, van Gemert MJC. Deep-hidden anastomoses in monochorionic twin placentae are harmless. Prenat Diagn 2007; 27:233-9. [PMID: 17186565 DOI: 10.1002/pd.1652] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES Our objective was to identify the clinical consequences of deep-hidden anastomoses that occur underneath the placental surface. METHODS Twelve placentae that underwent intrauterine laser ablation of placental anastomoses for twin-twin transfusion syndrome (TTTS) and 14 non-TTTS controls were investigated for deep-hidden anastomoses. Additionally, we investigated the inter-twin haemoglobin differences as an indicator for fetofetal transfusion. Placentae were divided into four groups: TTTS placentae without residual chorionic-plate anastomoses without deep-hidden anastomoses (group 1) and with deep-hidden anastomoses (group 2), and non-TTTS placentae with chorionic-plate anastomoses without deep-hidden anastomoses (group 3) and with deep-hidden anastomoses (group 4). RESULTS Deep-hidden anastomoses were identified in 58% (7/12) of the TTTS placentae after laser surgery and in 64% (9/14) of the non-TTTS placentae. Groups 1 and 2 had equal inter-twin haemoglobin differences: medians 1.4 and 1.2 gr/dL, respectively (p = 0.48). In group 3, the median inter-twin haemoglobin difference without deep-hidden anastomoses was 2.6 gr/dL (group 3) and with deep-hidden anastomoses (group 4) it was 5.1 gr/dL (p = 0.26). CONCLUSION Both comparisons imply that deep-hidden anastomoses did not cause any additional increase in Hb difference. In conclusion, haematological and additional hemodynamical analysis show that deep-hidden anastomoses are likely to occur without any clinical consequences.
Collapse
|
45
|
van Gemert MJC, Lanigan SW, Gutknecht N. LMS welcome to the new American editor–Peter Whittaker. Lasers Med Sci 2006. [DOI: 10.1007/s10103-006-0407-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
46
|
van den Wijngaard JPHM, Westerhof BE, Faber DJ, Ramsay MM, Westerhof N, van Gemert MJC. Abnormal arterial flows by a distributed model of the fetal circulation. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1222-33. [PMID: 16778066 DOI: 10.1152/ajpregu.00212.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.
Collapse
Affiliation(s)
- Jeroen P H M van den Wijngaard
- Laser Center and Department of Obstetrics and Gynecology, BMEYE Cardiovascular Monitoring Company, University of Amsterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
47
|
Ross MG, van den Wijngaard JPHM, van Gemert MJC. TTTS amnioreduction versus septostomy. Am J Obstet Gynecol 2006; 195:881-2; author reply 882. [PMID: 16949435 DOI: 10.1016/j.ajog.2005.11.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 11/29/2005] [Indexed: 11/29/2022]
|
48
|
van der Meer FJ, Faber DJ, Cilesiz I, van Gemert MJC, van Leeuwen TG. Temperature-dependent optical properties of individual vascular wall components measured by optical coherence tomography. J Biomed Opt 2006; 11:041120. [PMID: 16965148 DOI: 10.1117/1.2333613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Optical properties of tissues and tissue components are important parameters in biomedical optics. We report measurements of tissue refractive index n and the attenuation coefficient mu(t) using optical coherence tomography (OCT) of individual vascular wall layers and plaque components. Moreover, since the temperature dependence of optical properties is widely known, we compare measurements at room and body temperatures. A decrease of n and mu(t) is observed in all samples, with the most profound effect on samples with high lipid content. The sample temperature is of influence on the quantitative measurements within OCT images. For extrapolation of ex-vivo experimental results, especially for structures with high lipid content, this effect should be taken into account.
Collapse
Affiliation(s)
- Freek J van der Meer
- University of Amsterdam, Academic Medical Center, Laser Center, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
49
|
van den Wijngaard JPHM, Ross MG, van der Sloot JAP, Ville Y, van Gemert MJC. Simulation of therapy in a model of a nonhydropic and hydropic recipient in twin-twin transfusion syndrome. Am J Obstet Gynecol 2005; 193:1972-80. [PMID: 16325599 DOI: 10.1016/j.ajog.2005.04.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2004] [Revised: 04/19/2005] [Accepted: 04/19/2005] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study was undertaken to model the sequence of events that occurs after amnioreduction, laser therapy, and digoxin administration in twin-twin transfusion syndrome (TTTS) with and without a hydropic recipient twin. STUDY DESIGN We added amnioreduction, laser therapy, and digoxin administration to our mathematical TTTS model and simulated combinations of these therapies. RESULTS With a nonhydropic recipient, simulated amnioreduction delays the onset of hydrops. Conversely, with a hydropic recipient, amnioreduction aggravates the degree of hydrops. Furthermore, amnioreduction increases the transplacental fluid flow and may temporarily cause a hydropic donor. Laser therapy terminates the cause of recipient hydrops. Digoxin reduces the degree of recipient hydrops, but increases arteriovenous fetofetal transfusion. CONCLUSION Laser therapy is superior in TTTS with a hydropic recipient, because simulated amnioreduction aggravates the recipient's cardiovascular status. Digoxin benefits a hydropic recipient but slightly worsens the donor's condition. Therefore, TTTS presenting with a hydropic recipient prior to fetal viability (approximately 26 weeks) may be best treated with laser therapy, whereas more advanced gestations may be offered digoxin administration plus amnioreduction, to delay the progression of TTTS.
Collapse
Affiliation(s)
- Jeroen P H M van den Wijngaard
- Laser Center, Department of Obstetrics and Gynecology, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
50
|
van den Wijngaard JPHM, Umur A, Krediet RT, Ross MG, van Gemert MJC. Modeling a hydropic recipient twin in twin-twin transfusion syndrome. Am J Physiol Regul Integr Comp Physiol 2005; 288:R799-814. [PMID: 15539613 DOI: 10.1152/ajpregu.00635.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We developed a mathematical model of twin-twin transfusion syndrome (TTTS) that includes a hydropic recipient twin, adding interstitial and intracellular fluid compartments, fetal congestive cardiac failure, and the dynamics of renin-angiotensin system (RAS) mediators to our previous TTTS model. Ten differential equations for each twin, coupled by the net fetofetal transfusion of blood and blood components, i.e., colloids, osmoles, and RAS mediators, describe the development of fetal arterial and venous blood volumes, blood osmolality and colloid osmotic pressure (COP), interstitial fluid volume and COP, intracellular fluid volume, amniotic fluid volume and osmolality, and RAS mediator concentration. We included varying placental anastomoses, placental sharing, and amnionicity. The 20 differential equations were solved numerically from 0 to 40 wk with a 0.6-s time step. Consistent with clinical experience, model predictions are as follows. Unidirectional arteriovenous anastomoses and arteriovenous anastomoses inadequately compensated by oppositely directed anastomoses cause severe TTTS that includes a hydropic recipient. Adequately compensated arteriovenous anastomoses simulated TTTS without hydrops. The probability that oppositely directed anastomoses prevent onset of a hydropic recipient after TTTS onset, i.e., the largest interval between onset of TTTS and onset of hydrops in the recipient, was best for a venovenous anastomosis, closely followed by an arterioarterial and finally an oppositely directed arteriovenous anastomosis. Hydropic recipients have decreased amniotic fluid volume. Unequal placental sharing and amnionicity modify hydrops onset. In conclusion, our model simulates a sequence of events that results in a hydropic recipient twin in severe TTTS. The model may allow an assessment of the efficacy of current therapeutic interventions for TTTS cases that include a hydropic recipient twin.
Collapse
|