Medical Illustration in Conjoined Twin Surgical Separation Planning

In the last posts I highlighted the use of biomedical visualisation in scientific research and education, it also has an important role in medicine. Hospitals employ medical illustrators to help specialists and patients visualise medicine and science in a way that is simple to understand, interactive and interesting.

Medical illustrators are professional artists that create medical illustrations using traditional and digital techniques to represent anatomy with individual images from X–rays and CT scans to prepare the course of surgery. They also work in three dimensions, creating anatomical teaching models, patient simulators, and facial prosthetics. Medical Illustrators function as consultants and administrators within the field of bio communication, their drawings teaching others within the surgical profession and at medical schools. An example of this role includes planning the surgical separation of conjoined twins with 3D medical imaging, scientific visualisation and anatomic illustration.


Illustration developed for the separation of the Carlsen twins at the Mayo Clinic USA.

Understanding the anatomy of conjoined twins is difficult, accurate models and illustrations are important for pre-surgical assessments and planning as well as for reference during the actual operative procedure. The separation of conjoined twins is one of the most intricate procedures in medicine today, requiring massive teams of surgeons, nurses, anesthesiologists, and care givers to operate in harmony. Models provide a valuable basis for communication between the groups of specialists who are involved in the cases.

Conjoined twins develop as a result of the failed fusion of a single fertilized ovum however it is theorized that cranial fusion occurs between two separate embryos prior to the end of the 4th week of gestation. Craniopagus twins are conjoined twins who are fused at the cranium, those that survive birth present unique challenges in necessary surgical separation. This condition occurs when in the embryonic development process of Neurulation, the cranial neuropores remain open which are responsible for the ultimate fusion and formation of the brain stem and central nervous system. The fusion occurs from neural folds of two separate, dorsally oriented embryonic discs, and the union can occur only after the ectoderm is disrupted to allow the neural and surface ectodermal layers to separate from each other.


Stereolithography model produced of the bone and vascular structures of 2-year-old vertical craniopagus twins

Total craniopagus twins are defined as sharing extensive surface area with widely connected cranial cavities. There are four main categories- Frontal, Temporoparietal , Occipital and Parietal the latter considered the most unusual as the craniums of the two twins share the most veins, lobes and circulatory, often described as one brain shared by two individuals. In the last-half century advances have proven that a successful outcome is possible following separation of total craniopagus twins.

The neurosurgical aspects of craniopagus twin cases involve massive amounts of data from CT and MRI and angiograms imaging studies. Illustration assists surgeons in visualizing medical data produced. Neurosurgical applications for anatomical modelling centre on visualising vascular anomalies, bony anatomy representations for craniosynostosis surgery, and cranioplasty preparation. The recent use of modelling for the visualisation of the vascular systems of craniopagus twins has been a great benefit to neurosurgeons involved in these cases.

One team of surgeons used high-end virtual reality equipment to study the anatomy and rehearse the separation of a pair of vertical craniopagus twins. The team also used RP-generated anatomical models (3D printing) of the twins’ skulls and brain vasculature for identification of critical areas. Without advanced medical imaging and RP generated anatomical models, the planning for these operations would have been radically more difficult at best and impossible at worst.

conjoined dummies

Whole body anatomical model produced using 3D printing and in use by the hospital operating room staff, preparing to separate 2-year-old vertical craniopagus twins.


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3D Animated Life Cycle of Malaria

Every science student will encounter materials of the biomedical visual communication field throughout their education and are important tools in conveying complex scientific concepts. I had the opportunity to meet biomedical animator Drew Berry and decided to feature him and his work for this post.

Who is Drew Berry?


– This guy

Drew Berry s a biomedical animator at the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia and is one of the world’s foremost animators working in biomedical visualisation.

His scientifically accurate and aesthetically rich visualisations are enlightening cellular and molecular processes for a wide range of audiences. The animations have been shown in exhibitions, multimedia programs and television shows, and have received international recognition including an Emmy (2005) and a BAFTA Award (2004).

In these animations Berry synthesizes data across a variety of fields and presents them in engaging animations to enhance understanding of biological systems.

Berry created a two-part animation of the malaria life cycle that illustrates the pathogen’s development in the mosquito host and its invasion of human cells. These two examples will be used here with an overview of malaria before viewing.

What is Malaria?


3D visualisation of mosquito feeding on human blood and injecting saliva infected with malaria parasites into bloodstream.

Malaria is a mosquito-borne infectious disease of humans and other animals caused by protists (a type of microorganism) of the genus Plasmodium. Malaria causes symptoms that typically include fever and headache, which in severe cases can progress to coma or death.

The World Health Organization has estimated that in 2010, there were 219 million documented cases of malaria. That year, between 660,000 and 1.2 million people died from the disease, many of who were children in Africa.

Life Cycle of Malaria


3D Visualisation of sporocite form of malaria parasite infecting a human red blood cell

The life cycle involves two different hosts: in most cases a female mosquito (the primary host) transmits a motile infective form called the sporozoite to a vertebrate host such as a human (the secondary host) acting as a transmission vector. A sporozoite travels through the blood vessels to liver cells where it undergoes asexual reproduction transforming and producing thousands of merozoites.

These infect new red blood cells transforming yet again into trophozoites, which eat the contents of the red blood cells and initiate a series of synchronous asexual multiplication cycles every 48 to 72 hours. This induces lysis of the red blood cell or bursting causing the release of toxins and mezoites into the bloodstream hence the cycles of fever and chills, the infective cycle then beginning anew.


3D Visualisation of cell lysis/bursting of infected red blood cell releasing malaria parasite form of mezoites.

After several rounds of replication merozoites develop into immature gametes, or gametocytes and when a fertilised mosquito bites an infected person, gametocytes are taken up with the blood and mature in the mosquito gut. Here they develop into sperm and eggs then fusing to form zygotes that undergo meiosis to eventually develop into new haploid sporozoites. They migrate to the insect’s salivary glands, ready to infect a new vertebrate host. The sporozoites are injected into the skin alongside saliva when the mosquito takes a subsequent blood meal.

The parasites multiply in the vertebrate as before and are then available to back- infect the next generation of mosquitos. By exploiting the relationship between mosquitos and vertebrates, malaria ensure their own reproduction and distribution. They also reduce the defence strategies available to hosts since only part of the life cycle occurs in each host. Only female mosquitoes feed on blood; and transmit the disease.

Head starting to spin? This is where Drew Berry and Biomedical Visualisation comes in to help illustrate the big picture.

3D Animated Life Cycle of Malaria- Drew Berry


Cowman AF, Berry D, Baum J (2012). “The cellular and molecular basis for malaria parasite invasion of the human red blood cell”. Journal of Cell Biology Issue 198, Vol 6, pp 961–71.

Knox. B. Ladiges P. Evans B, Saint, R. (2006) “Biology: An Australian Focus 3rd Edition” pp 846-847. McGraw Hill Australia NSW.

Nayyar GML, Breman JG, Newton PN, Herrington J (2012). “Poor-quality antimalarial drugs in southeast Asia and sub-Saharan Africa”. Lancet Infectious Diseases Vol 12  Issue 6 pp 488–96.

Schlagenhauf-Lawlor (2008) Traveller’s Malaria, pp. 70–1.

The Walter Eliza Hall IInstitute of Medical Research (2012) accessed 15.5.13

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3D Printed Faces of DNA

The field of biomedical visualisation and its use to communicate scientific research concepts is increasing with advances in visual and scientific technology. As a student in the sciences and arts this is an area of interest, observing the two worlds inter-connect, transcend boundaries and discover.

Heather Dewey-Hagborg, a PhD student studying electronic arts at Rensselaer Polytechnic Institute in Troy, New York has taken this a step further in her exhibited series called “Stranger Visions”. Using actual DNA from found human genetic material Hagborg generated life-size facial model sculptures of human individuals using 3D printing.

dna facial portraitsExhibited series “Stranger Visions” by Heather Dewey-Hagborg

How did she do it? From collecting samples of hair, fingernails, chewing gum and cigarette butts (eww..) from the streets of New York she then used DNA extraction and the technique of Polymerase Chain Reaction (PCR). A small portion of the sample was incubated in a chemical solution, put in a centrifuge and repeated multiple times until the chemicals successfully extract purified DNA. With then the running of PCR the mitochondrial DNA was sent to a lab returning with around 400 base pair sequences of guanine, adenine, thymine and cytosine (G,A,T and C)

From this sequence Hagborg focused on 40-50 different traits that were analysed such as the person’s ancestry, gender, eye colour, propensity to be overweight and other traits related to facial morphology such as the space between one’s eyes. These parameters were then entered into a computer program using the Basel Morphable Model to create a 3D model of that person’s face and the file sent to a 3D printer to be transformed into sculpture.

Stranger Visions

Exhibited series “Stranger Visions” by Heather Dewey Hagborg

Limitations exist including what is actually known about how genes are linked to particular facial features in addition to the role of Epigenetics and the environment of how facial features develop. For Instance the artist had no way to identify the age of a person based on the DNA sample, the process used created a 25-year-old version of the person.

As the samples are from anonymous individuals there is no way of knowing how accurate Hagborg’s sculptures are without a direct comparison. However the artist used the same process to produce a 3D model sculpture from a sample of her own genetic material, the result bearing a “family resemblance”. Also most of the people used to train the The Basel Morphable Model system were of European descent, which led to some problems in creating portraits for individuals who were not.

The technology has particular utility for forensic biology and crime solving within society with ethical implications of genetic surveillance. The artists comments  “The idea came from noticing that we are leaving genetic material everywhere. Combined with increasing accessibility to molecular biology, these techniques are available today. The question really is what are we going to do with it?”

On a finishing note the artist was recently contacted by Dalaware’s medical examiner’s office asking for assistance with the remains of a woman that have gone unidentified for 20 years. A 3D DNA facial portrait may be a useful clue for investigators in solving the mystery.

artist dna portrait

Artist- Heather Dewey-Hagborg and her self DNA 3D facial portrait.


Gambino. M, 2013. “Creepy or Cool? Portraits Derived From the DNA in Hair and Gum Found in Public Places” Smithsonian, accessed 5.5.2013

Jobson.C, 2013 “Stranger Visions: DNA Collected from Found Objects used to create 3D Portraits” Colossal, accessed 5.5.2013

Walters. H, 2013.”A Portrait of you from a Single Hair: The Work of Heather Dewey-Hagborg”
TED blog, accessed 25.6.2013