Usefulness of intraoperative fluorescence imaging to evaluate local anatomy in hepatobiliary surgery

Background/Purpose

One of the major complications encountered in hepatobiliary surgery is the incidence of bile duct and blood vessel injuries. It is sometimes difficult during surgery to evaluate the local anatomy corresponding to hepatic arteries and bile ducts. We investigated the potential utility of an infrared camera system as a tool for evaluating local anatomy during hepatobiliary surgery.

Methods

An infrared camera system was used to detect indocyanine green fluorescence in vitro. We also employed this system for the intraoperative fluorescence imaging of the arteries and biliary system in a pig. Further, we evaluated blood flow in the hepatic artery, portal vein, and liver parenchyma during a human liver transplant and we investigated local anatomy in patients undergoing cholecystectomy.

Results

Fluorescence confirmed that indocyanine green was distributed in serum and bile. In the pig study, we confirmed the fluorescence of the biliary system for more than 1 h. In the liver transplant recipient, blood flow in the hepatic artery and portal vein was confirmed around the anastomosis. In most of the patients undergoing cholecystectomy, fluorescence was observed in the gallbladder, cystic and common bile ducts, and hepatic and cystic arteries.

Conclusions

Intraoperative fluorescence imaging in hepatobiliary surgery facilitates better understanding of the anatomy of arteries, the portal vein, and bile ducts.     

Utility of augmented reality system in hepatobiliary surgery

Background/purpose

The aim of this study was to evaluate the utility of an image display system for augmented reality in hepatobiliary surgery under laparotomy.

Methods

An overlay display of organs, vessels, or tumor was obtained using a video see-through system as a display system developed at our institute. Registration between visceral organs and the surface-rendering image reconstructed by preoperative computed tomography (CT) was carried out with an optical location sensor. Using this system, we performed laparotomy for a patient with benign biliary stricture, a patient with gallbladder carcinoma, and a patient with hepatocellular carcinoma.

Results

The operative procedures performed consisted of choledochojejunostomy, right hepatectomy, and microwave coagulation therapy. All the operations were carried out safely using images of the site of tumor, preserved organs, and resection aspect overlaid onto the operation field images observed on the monitors. The position of each organ in the overlaid image closely corresponded with that of the actual organ. Intraoperative information generated from this system provided us with useful navigation. However, several problems such as registration error and lack of depth knowledge were noted.

Conclusion

The image display system appeared to be useful in performing hepatobiliary surgery under laparotomy. Further improvement of the system with individualized function for each operation will be essential, with feedback from clinical trials in the future.     

Intraoperative fluorescent imaging using indocyanine green for liver mapping and cholangiography

Background

Preoperative imaging is widely used and extremely helpful in hepatobiliary surgery. However, transfer of preoperative data to a intraoperative situation is very difficult. Surgeons need intraoperative anatomical information using imaging data for safe and precise operation in the field of hepatobiliary surgery. We have developed a new system for mapping liver segments and cholangiograms using intraoperative indocyanine green (ICG) fluorescence under infrared light observation.

Method

The imaging technique for mapping liver segments and cholangiogram based on ICG fluorescence used an infrared-based navigation system. Eighty one patients with liver tumors underwent hepatectomy from 2006, January to 2009, March. In liver surgery, 1 ml of ICG was injected via the portal vein under observation by the fluorescent imaging system. Fourteen patients were underwent laparoscopic cholecystectomy for chronic cholecystitis with gallstones. In laparoscopic cholecystectomy, 5 ml of ICG was administered intravenously just before operation and the bile duct was observed using the infrared-based navigation system.

Result

This new technique successfully identified stained subsegments and segments of the liver in 73 of 81 patients (90.1%). Moreover, clear mapping of liver segments was obtained even against a background of liver cirrhosis. Fluorescent cholangiography clearly showed the common bile duct and cystic duct in 10 of 14 patients (71.4%). No adverse reactions to the ICG were encountered.

Conclusion

Application of this technique allows intraoperative identification of anatomical landmark in hepatobiliary surgery.     

Short rigid scope and stereo-scope designed specifically for open abdominal navigation surgery: clinical application for hepatobiliary and pancreatic surgery

Background

We have reported the utility of an image display system using augmented reality (AR) technology in hepatobiliary surgery under laparotomy. Among several procedures, we herein report a system using a novel short rigid scope and stereo-scope, both designed specifically for open abdominal navigation surgery, and their clinical application for hepatobiliary and pancreatic surgery.

Methods

The 3D reconstructed images were obtained from preoperative computed tomography data. In our specialized operating room, after paired-point matching registration, the reconstructed images are overlaid onto the operative field images captured by the short rigid scopes. The scopes, which are compact and sterilizable, can be used in the operative field. The stereo-scope provides depth information. Eight patients underwent operations using this system, including hepatectomy in two, distal pancreatectomy in three, and pancreaticoduodenectomy in three patients. The stereo-scope was used in five patients.

Results

All eight operations were performed safely using the novel short rigid scopes, and stereo images were acquired in all five patients for whom the stereo-scope was used. The scopes were user friendly, and the intraoperative time requirement for our system was reduced compared with the conventional method.

Conclusions

The novel short rigid scope and stereo-scope seem to be suitable for clinical use in open abdominal navigation surgery. In hepatobiliary and pancreatic surgery, our novel system may improve the safety, accuracy and efficiency of operations.     

Reflected Illumination-Type Imaging System for the Development of Infrared Fluorescence Endoscopy

Fluorescent labeled monoclonal antibodies against carcinoembryonic antigen (CEA) may provide a specific label for lesions of the GI tract. We previously developed an indocyanine green (ICG) derivative (ICG N-hydroxy sulfo succinimide ester; ICG-sulfo-Osu) as a fluorescent label that is excited by infrared rays and is suitable for vital immunohistochemical staining. We also previously developed a transmitted illumination-type (transmitted type) fluorescence imaging system that uses infrared rays to detect ICG-sulfo-Osu. In this paper we describe a new reflected illumination-type (reflected type) imaging system for infrared fluorescence endoscopy. We tested the efficacy of this system on sections of human esophagus and normal skeletal muscle stained with ICG-sulfo-Osu labeled anti-epithelial membrane antigen (EMA) antibody, and on sections of human gastric cancer tissue stained with ICG-sulfo-Osu labeled anti-CEA antibody. Infrared fluorescent images were obtained with both fluorescent antibodies, and results correlated well with oxidized DAB-positive sites. Vital immunohistochemical staining of micro cancers should be detectable by exciting an ICG-sulfo-Osu labeled antibody specific to the tumor cells with infrared rays, using this reflected type imaging system.     

Development of an Imaging System Using Fluorescent Labeling Substances Excited by Infrared Rays

Abstract: An indocyanine green (ICG) derivative (ICG N-hydroxy sulfosuc-cinimide ester; ICG-sulfo-OSu) has been developed as an antibody labeling substance suitable for vital immunohistochemical staining. However, an appropriate fluorescence imaging system for ICG-sulfo-OSu using infrared rays has not as yet been reported. Therefore, we developed such a system. The absorption maxima of ICG and ICG-sulfo-OSu in buffer solution are both at 795 nm, the excitation maxima of their fluorescence spectra in buffer solution at 768 nm, and their emission maxima at 807 nm. An imaging system using an excitation filter with transmission at 710-790 nm and a barrier filter with transmission at 810-920 nm was constructed, and fluorescent images of ICG-sulfo-OSu labeled anti-epithelial membrane antigen (EMA) antibody were obtained with this system. Thus, vital immunohistochemical staining of microcancers under infrared ray excitation should now be possible, by exciting an ICG-sulfo-OSu labeled antibody specific to the tumor cells with infrared rays, using this imaging system.     

Evaluation of cholecystic venous flow using indocyanine green fluorescence angiography

Background/purpose

The cholecystic veins are thought to be an important metastatic route of gallbladder carcinoma to the liver. In the present study we evaluated the cholecystic venous drainage area, utilizing a novel method, indocyanine green (ICG) fluorescence angiography after superselective catheterization of the cholecystic artery, to detect and elucidate cholecystic venous flow.

Methods

Cannulation of the cholecystic artery was performed under laparotomy in nine patients who required a cholecystectomy. After ICG injection into the cholecystic artery, the cholecystic venous flow images were visualized with a near-infrared camera system and were analyzed according to site, shape, and time of fluorescence.

Results

Fluorescence images of the cholecystic venous flow could be viewed as real-time images in all patients. We demonstrated that the route of the cholecystic venous flow could be classified into two patterns: type 1, in which the cholecystic veins flowed directly into the hepatic parenchyma adjacent to the gallbladder; and type 2, in which the veins flowed into sites separate from the gallbladder. In the type 1 pattern, fluorescence was observed in segment (S; defined according to Couinaud’s nomenclature) 4a or S5 adjacent to the gallbladder in all cases. On the other hand, in the type-2 pattern, fluorescence was observed in S4a (6/9), S5 (8/9), S4b (2/9), S3 (2/9), S1 (1/9), S2 (1/9), and S8 (1/9) distant from the gallbladder. Overall, two-thirds of the cases showed fluorescence in segments other than S4a or S5.

Conclusions

Indocyanine green (ICG) fluorescence angiography is considered to be a useful method to detect and elucidate cholecystic venous flow in real time. This study showed that the cholecystic venous flow spread to the liver through two different pathways, one that flowed directly into the hepatic parenchyma adjacent to the gallbladder, while the other flowed into sites separate from the gallbladder. Taking these findings into consideration, we may therefore need to reconsider the preventive effects of a hepatic resection.     

Intraoperative assessment of reconstructed vessels in living-donor liver transplantation, using a novel fluorescence imaging technique

Background/Purpose

In living-donor liver transplantation (LDLT), hepatic arterial thrombosis and portal venous thrombosis are critical problems that can result in graft loss. Only intraoperative Doppler ultrasound (IDUS) is able to evaluate blood flow in the reconstructed vessels. The aim of this study was to evaluate the utility of a newly developed fluorescence imaging technique using indocyanine green (ICG) for visualizing reconstructed vessels.

Methods

In three patients who had undergone LDLT, IDUS was performed after reconstruction of the portal vein and hepatic artery. Fluorescence images were then recorded, using a SPY system (Novadeq Technologies), which employs ICG as a fluorescent imaging medium activated by light. The ICG (3.75?mg) was injected intravenously, then, 10?s later, the images were recorded for 30?s (first photographic recording). Two minutes later, the same procedure was repeated (second photographic recording), and 40?min later, images were obtained without injection of ICG (third photographic recording).

Results

After portal venous reconstruction, IDUS demonstrated a nonphasic and continuous waveform, with a mean velocity of 52.1?cm/s and a mean portal blood flow volume of 69.5?ml/s per kg. After hepatic arterial reconstruction, a pulsatile waveform with a mean peak systolic velocity of 52.4?cm/s and a mean resistance index of 0.76 was obtained. The first photographic recording clearly visualized the blood flow in the reconstructed hepatic artery, without kinking or stenosis, in all three patients. The second photographic recording visualized the flow in the portal vein without stenosis, kinking, or stagnation. The third photographic recording demonstrated the excretion of ICG into bile, thus confirming bile production by the grafts.

Conclusions

Fluorescence imaging can clearly visualize the reconstructed hepatic artery and portal vein and demonstrate the production of bile by a transplanted liver graft. A combination of IDUS and the new system can guarantee the patency of the reconstructed vessels.     

Fluorescence angiography-assisted debridement of critically perfused glabrous skin in degloving foot injuries: Two case reports

Rationale:Degloving foot injuries are challenging to treat and associated with life-long sequelae for patients. An appropriate debridement of ischemic soft tissues with maximal preservation of glabrous skin is key during the reconstruction of these injuries. Indocyanine green (ICG) fluorescence angiography is an established technique for the intraoperative evaluation of tissue perfusion.Patient concerns:Two patients sustained complex foot injuries in traffic accidents, including multiple fracture dislocations and extensive degloving of the plantar skin.Diagnosis:Clinical inspection revealed significant degloving of the glabrous skin in both patients.Interventions:After fracture fixation, ICG fluorescence angiography-assisted debridement with immediate latissimus dorsi free flap reconstruction was performed.Outcomes:In both cases, this technique allowed a precise debridement with maximal preservation of the glabrous skin. The healing of the remaining glabrous skin was uneventful and the 6-month follow-up was characterized by stable soft tissues and satisfying ambulation.Lessons:ICG fluorescence angiography is a safe, user-friendly, and quick procedure with minimal risks, expanding the armamentarium of the reconstructive surgeon. It is highly useful for the debridement of extensive plantar degloving injuries and may also help to minimize the number of procedures and the risk of infection.     

Navigation and image-guided HBP surgery: a review and preview

Image‐guided surgery and navigation have resulted from convergent developments in radiology, teletransmission, and computer science. Patient selection and preoperative planning in hepatobiliary‐pancreatic (HBP) surgery rely on preoperative imaging. The operative procedure is finally led by the fusion of additional information gained by the palpating hand and intraoperative ultrasound. Despite advances in reducing morbidity and mortality, decisions are often hardly quantifiable and are restricted to super‐specialists in HBP surgery. New developments in computed tomography (CT) and magnetic resonance imaging (MRI) technology have led to the possibility of the volumetric prediction of liver resections. These data can be shared via telemedicine and used for simulation and training. Three‐dimensional (3D) reconstructions have led to a better topologic understanding of tumor‐vascular tree relations in the individual patient. With the increasing use of ablative procedures and laparoscopy, intraoperative imaging and navigation will hold increasing significance for the HBP surgeon. Flat screen monitors adjacent to the surgical field present computer‐generated 3D virtual liver resection proposals which can be transferred into the real liver. The main obstacles in HBP navigation are the flexibility and mobility of the target organ. Intrahepatic and surface markers seem to be mandatory for computer‐navigated surgery. The first feasibility studies are promising.     

Intraoperative exploration of biliary anatomy using fluorescence imaging of indocyanine green in experimental and clinical cholecystectomies

Background/purpose

We evaluated the usefulness of intraoperative exploration of the biliary anatomy using fluorescence imaging with indocyanine green (ICG) in experimental and clinical cholecystectomies.

Methods

The experimental study was done using two 40-kg pigs and the clinical study was done in 12 patients for whom cholecystectomy was planned from January 2009 to June 2009. Initially we used a laparoscopic approach for the evaluation of fluorescence imaging of the biliary system in the two pigs. Then the clinical study was started on the basis of these experimental results. ICG (1.0 ml/body of 2.5 mg/ml ICG) was infused 1–2 h before surgery. With the subjects under general anesthesia we observed in real time the condition of the biliary tract under the guidance of fluorescence imaging employing an infrared camera or a prototype laparoscope. ICG was added intravenously to observe the location or flow condition of the cystic artery.

Results

We obtained a clear view of the biliary tract and the location of the cystic duct in the two pigs. Local compression with a transparent hemispherical plastic device was effective for offering a clearer view. The biliary tract, except for the gallbladder, was clearly recognized in all clinical subjects. Local compression with a transparent hemispherical plastic device for open cholecystectomy and a flat plastic device for laparoscopy provided clearer visualization of the confluence between the cystic duct and common bile duct or common hepatic duct. The location of the cystic artery was revealed after division of the connective tissues, and the flow condition of the cystic artery was confirmed 7–10 s after intravenous re-infusion of ICG. There were no adverse events related to the intraoperative procedure or the ICG itself.

Conclusions

This method is safe and easy for the identification of the biliary anatomy, without requiring cannulation into the cystic duct, X-ray equipment, or the use of radioactive materials. Although fluorescence imaging is still at an early stage of application in comparison with ordinary intraoperative cholangiography, we expect that this method will become routine, offering a lower degree of invasiveness that will help avoid bile duct injury.     

A near-infrared AIE fluorescent probe for myelin imaging: From sciatic nerve to the optically cleared brain tissue in 3D

Myelin, the structure that surrounds and insulates neuronal axons, is an important component of the central nervous system. The visualization of the myelinated fibers in brain tissues can largely facilitate the diagnosis of myelin-related diseases and understand how the brain functions. However, the most widely used fluorescent probes for myelin visualization, such as Vybrant DiD and FluoroMyelin, have strong background staining, low-staining contrast, and low brightness. These drawbacks may originate from their self-quenching properties and greatly limit their applications in three-dimensional (3D) imaging and myelin tracing. Chemical probes for the fluorescence imaging of myelin in 3D, especially in optically cleared tissue, are highly desirable but rarely reported. We herein developed a near-infrared aggregation-induced emission (AIE)-active probe, PM-ML, for high-performance myelin imaging. PM-ML is plasma membrane targeting with good photostability. It could specifically label myelinated fibers in teased sciatic nerves and mouse brain tissues with a high–signal-to-background ratio. PM-ML could be used for 3D visualization of myelin sheaths, myelinated fibers, and fascicles with high-penetration depth. The staining is compatible with different brain tissue–clearing methods, such as Clear^T and Clear^T2. The utility of PM-ML staining in demyelinating disease studies was demonstrated using the mouse model of multiple sclerosis. Together, this work provides an important tool for high-quality myelin visualization across scales, which may greatly contribute to the study of myelin-related diseases.

Myelination, which involves the ensheathment of axons by oligodendrocytes in the central nervous system (CNS) or Schwann cells in the peripheral nervous system (PNS), is an evolutionary advantage to the complex nervous system of vertebrates (1, 2). By wrapping glial membranes around axons, axonal insulation facilitates saltatory conduction up to 100-fold compared to unmyelinated axons (3, 4). Additionally, the architecture of axo-glial junctions creates polarized domains for protein segmentation, thus allowing the local clustering of ion channels and the corresponding downstream signaling, as well as the accumulation of scaffolding and cytoskeletal proteins for axonal transport (5, 6). Given the unique axo-glial organization and its functions, the demyelination in neurological disorders, such as multiple sclerosis and leukodystrophies, is associated with progressive axonal loss, cognitive impairment, and motor symptoms (7–11). Myelin imaging is therefore considered as not only an approach for diagnosing neuropathies but also a research tool to understand the mechanism underlying demyelinating diseases (12, 13).Provided that billions of neurons are densely populated in the brain with myelinated nerve fibers projected to the inner part of the brain, labeling tools enabling deep-tissue imaging with high spatial resolution will greatly facilitate the reconstruction of neural networks in three-dimension (3D) (14, 15). Some label-free imaging techniques, such as spectral confocal reflectance microscopy (14), coherent anti-Stokes Raman scattering (16), third-harmonic generation (17), and optical coherence tomography (OCT) (18), are developed to offer powerful methodological toolboxes for uncovering mechanisms of myelin generation and neuroplasticity in the live brain. On the other hand, fluorescence imaging is an indispensable technique for visualizing biological molecules and structures, as well as tracking changes in distribution, morphology, and the intensity of the target of interest with a higher spatial resolution. It is also widely used for myelin imaging (19). Immunofluorescence staining, fluorescent protein labeling, and small-molecule fluorescent probe staining are three commonly used methods for fluorescence biostaining and imaging. Compared with the immunostaining and genetically encoded fluorescent protein labeling, which involves tedious and time-consuming sample preparation procedures, small-molecule fluorescent probe staining offers a uniquely reliable and feasible method for brain tissue staining and imaging (20). The relatively small size, low costs, ease of use, and reliability of small-molecule fluorescent probes are advantageous to visualize morphological details in tissues, especially for 3D tissues (21). Generally, an ideal probe for deep-tissue imaging should have the following characteristics: 1) near-infrared (NIR) emission with a high-penetration depth and low interference from biological autofluorescence; 2) targetability to a desired structure or molecule; 3) bright and photostable; 4) adaptable to multiplexed tissue interrogation; and 5) easy to synthesis and use (20). Despite that currently available commercial myelin-specific fluorescent probes, such as sulforhodamine 101, Vybrant DiD (DiD), and FluoroMyelin Green/Red, are widely used, they have shortcomings in different degrees of background staining, low-staining contrast, low brightness, and poor tissue permeability (22–27). Actually, sulforhodamine 101 is more commonly used in labeling astrocytes (28). While lipophilic probes, such as DiD and FluoroMyelin Green/Red, stain the membranes of the cells and thus have a high concentration of dye accumulated in the myelin structures, which are formed by multilamellar membrane wrapping (29). This contributes to the myelin selectivity of these probes, but the high concentration of these probes in myelin at the same time may lead to fluorescence self-quenching, resulting in a low–signal-to-background ratio (30). Though advanced microscopy and tissue-clearing methods are developed in achieving better imaging quality, unoptimized probes hinder high-quality imaging and the tracking of myelinated axons in deep brain. Currently, there is only one reported case of deep-tissue myelin imaging using the chemical probe (23). This method uses the commercial probe, DiD, which has a poor tissue permeability so that the pretreatment of the tissues with Triton X-100 is required to facilitate dye penetration. The pretreatment step, however, also washes away the lipids and destroys some fine structures of myelin, thus greatly reducing the myelin selectivity of the staining (20). Therefore, fluorescent probes for 3D myelin imaging with good selectivity, high–signal-to-background ratio, good tissue permeability, and tissue-clearing compatibility are highly desirable.In recent years, fluorescent probes with aggregation-induced emission (AIE) properties have emerged as a group of excellent candidates for bioimaging (31–34). AIE luminogens (AIEgens) show weak emission in dilute solution but emit strongly in the aggregated state, which offers low background fluorescence, strong signal-to-background ratio, and good photostability in practical bioimaging (35–38). With the rational molecular designs, AIE-based NIR materials offer superior performance in biomolecular imaging and tracing (39–41). However, tissue bioimaging using AIE materials currently are mostly focused on tumor imaging, vascular imaging, and lymphatic imaging. The application of AIE materials in neuroimaging remains to be explored. This prompts us to develop a type of NIR AIE probes for 3D myelin imaging in brain tissues.Different from the plasma membrane of eukaryotic cells, which contains about 40% of lipids, the myelin membrane contains as many as 70% of lipids (42, 43). Therefore, targeting the plasma membrane lipids is a feasible approach for the designing of the myelin-specific probe (23). Based on this postulation, we developed a fluorescent probe, named PM-ML, for myelin imaging. PM-ML showed AIE properties with NIR emission. It specifically labeled the plasma membrane in live and fixed cells with excellent photostability. Compared with the commercial myelin probes FluoroMyelin Red and DiD, PM-ML selectively stained myelinated regions in the brain of wild-type (WT) mice with a high–signal-to-background ratio. Furthermore, it could be used for 3D myelin imaging in mouse brain tissues with good tissue penetration and high specificity. We also demonstrated a lack of myelination in hypomyelinated shiverer mutant mice by using PM-ML.     

S100B and its relation to cerebral oxygenation in neonates and infants undergoing surgery for congenital heart disease

Objectives: Neonates and infants undergoing surgery for congenital heart disease are at risk for developmental impairment. Hypoxic‐ischemic brain injury might be one contributing factor. We aimed to investigate the perioperative release of the astro‐ cyte protein S100B and its relation to cerebral oxygenation.
Methods: Serum S100B was measured before and 0, 12, 24, and 48 hours after sur‐ gery. Cerebral oxygen saturation was derived by near‐infrared spectroscopy. S100B reference values based on preoperative samples; concentrations above the 75th per‐ centile were defined as elevated. Patients with elevated S100B at 24 or 48 hours were compared to cases with S100B in the normal range. Neonates (≤28 days) and infants (>28 and ≤365 days) were analyzed separately due to age‐dependent release of S100B.
Results: Seventy‐four patients underwent 94 surgical procedures (neonates, n = 38; infants, n = 56). S100B concentrations were higher in neonates before and after sur‐ gery at all time points (P ≤ .015). Highest values were noticed immediately after sur‐ gery. Postoperative S100B was elevated after 15 (40.5%) surgeries in neonates. There was no difference in pre‐, intra‐, or postoperative cerebral oxygenation. In in‐ fants, postoperative S100B was elevated after 23 (41.8%) procedures. Preoperative cerebral oxygen saturations tended to be lower (53 ± 12% vs 59 ± 12%, P = .069) and arterial‐cerebral oxygen saturation difference was higher (35 ± 11% vs 28 ± 11%, P = .018) in infants with elevated postoperative S100B. In the early postoperative course, cerebral oxygen saturation was lower (54 ± 13% vs 63 ± 12%, P = .011) and arterial‐cerebral oxygen saturation difference was wider (38 ± 11% vs 30 ± 10%, P = .008). Cerebral oxygen saturation was also lower for the entire postoperative course (62 ± 18% vs 67 ± 9%, P = .047).
Conclusions: Postoperative S100B was elevated in about 40% of neonates and in‐ fants undergoing cardiac surgery. Infants with elevated postoperative S100B had impaired perioperative cerebral tissue oxygenation. No relation between S100B and cerebral oxygenation could be demonstrated in neonates.     

Biopsy of a complicated right atrial mass using CARTO 3‐dimensional electro‐anatomic mapping

We report the successful biopsy of a right atrial fatty mass using CARTO 3‐dimensional electro‐anatomic mapping fused with cardiac MRI. Fluoroscopic guidance within the cardiac chambers lacks precision and therefore risks geographical miss of the intended target and cardiac perforation. CARTO mapping fused with cardiac MRI facilitated precise navigation of the bioptome thereby ensuring a successful biopsy of the intended tissue while minimizing the risks of inadvertent trauma to adjacent tissue. © 2014 Wiley Periodicals, Inc.