Exhalomics as a noninvasive method for assessing rumen fermentation in dairy cows: Can exhaled-breath metabolomics replace rumen sampling?

Previously, we used secondary electrospray ionization-mass spectrometry (SESI-MS) to investigate the diurnal patterns and signal intensities of exhaled (EX) volatile fatty acids (VFA) of dairy cows. The current study aimed to validate the potential of an exhalomics approach for evaluating rumen fermentation. The experiment was conducted in a switchback design, with 3 periods of 9 d each, including 7 d for adaptation and 2 d for sampling. Four rumen-cannulated original Swiss Brown (Braunvieh) cows were randomly assigned to 1 of 2 diet sequences (ABA or BAB): (A) low starch (LS; 6.31% starch on a dry matter basis) and (B) high starch (HS; 16.2% starch on a dry matter basis). Feeding was once per day at 0830 h. Exhalome (with the GreenFeed System), and rumen samples were collected 8 times to represent every 3 h of a day, and EX-VFA and ruminal (RM)-VFA were analyzed using SESI-MS and HPLC, respectively. Furthermore, the VFA concentration in the gas phase (HR-VFA) was predicted based on RM-VFA and Henry's Law (HR) constants. No interactions were identified between the types of diets (HS vs. LS) and the measurement methods on daily average VFA profiles (RM vs. EX or HR vs. EX), suggesting a consistent performance among the methods. Additionally, when the 3-h interval VFA data from HS and LS diets were analyzed separately, no interactions were observed between methods and time of day, indicating that the relative daily pattern of VFA molar proportions was similar regardless of the VFA measurement method used. The results revealed that the levels of acetate sharply increased immediately after feeding, trailed by an increase in the acetate:propionate ratio and a steady increase for propionate (2 h after feeding the HS diet, 4 h for LS), and butyrate. This change was more pronounced for the HS diet than the LS diet. However, there was no overall diet effect on the VFA molar proportions, although the measurement methods affected the molar proportions. Furthermore, we observed a strong positive correlation between the levels of RM and EX acetate for both diets (HS: r = 0.84; LS: r = 0.85), RM and EX propionate (r = 0.74), and RM and EX acetate:propionate ratio (r = 0.80). Both EX-VFA and RM-VFA exhibited similar responses to feeding and dietary treatments, suggesting that EX-VFA could serve as a useful proxy for characterizing RM-VFA molar proportions to evaluate rumen fermentation. Similar relationships were observed between RM-VFA and HR-VFA. In conclusion, this study underscores the potential of exhalomics as a reliable approach for assessing rumen fermentation. Moving forward, research should further explore the depth of exhalomics in ruminant studies to provide a comprehensive insight into rumen fermentation metabolites, especially across diverse dietary conditions.

Exhaled volatile fatty acids, ruminal methane emission, and their diurnal patterns in lactating dairy cows.

To date, the commonly used methods to assess rumen fermentation are invasive. Exhaled breath contains hundreds of volatile organic compounds (VOC) that can reflect animal physiological processes. In the present study, for the first time, we aimed to use a noninvasive metabolomics approach based on high-resolution mass spectrometry to identify rumen fermentation parameters in dairy cows. Enteric methane (CH4) production from 7 lactating cows was measured 8 times over 3 consecutive days using the GreenFeed system (C-Lock Technology Inc.). Simultaneously, exhalome samples were collected in Tedlar gas sampling bags and analyzed offline using a secondary electrospray ionization high-resolution mass spectrometry system. In total, 1,298 features were detected, among them targeted exhaled volatile fatty acids (eVFA; i.e., acetate, propionate, butyrate), which were putatively annotated using their exact mass-to-charge ratio. The intensity of eVFA, in particular acetate, increased immediately after feeding and followed a similar pattern to that observed for ruminal CH4 production. The average total eVFA concentration was 35.5 count per second (CPS), and among the individual eVFA, acetate had the greatest concentration, averaging 21.3 CPS, followed by propionate at 11.5 CPS, and butyrate at 2.67 CPS. Further, exhaled acetate was on average the most abundant of the individual eVFA at around 59.3%, followed by 32.5 and 7.9% of the total eVFA for propionate and butyrate, respectively. This corresponds well with the previously reported proportions of these VFA in the rumen. The diurnal patterns of ruminal CH4 emission and individual eVFA were characterized using a linear mixed model with cosine function fit. The model characterized similar diurnal patterns for eVFA and ruminal CH4 and H2 production. Regarding the diurnal patterns of eVFA, the phase (time of peak) of butyrate occurred first, followed by that of acetate and propionate. Importantly, the phase of total eVFA occurred around 1 h before that of ruminal CH4. This corresponds well with existing data on the relationship between rumen VFA production and CH4 formation. Results from the present study revealed a great potential to assess the rumen fermentation of dairy cows using exhaled metabolites as a noninvasive proxy for rumen VFA. Further validation, with comparisons to rumen fluid, and establishment of the proposed method are required.

Gas-phase production and photoelectron spectroscopy of the smallest fullerene, C20

Fullerenes are graphitic cage structures incorporating exactly twelve pentagons. The smallest possible fullerene is thus C20, which consists solely of pentagons. But the extreme curvature and reactivity of this structure have led to doubts about its existence and stability. Although theoretical calculations have identified, besides this cage, a bowl and a monocyclic ring isomer as low-energy members of the C20 cluster family, only ring isomers of C20 have been observed so far. Here we show that the cage-structured fullerene C20 can be produced from its perhydrogenated form (dodecahedrane C20H20) by replacing the hydrogen atoms with relatively weakly bound bromine atoms, followed by gas-phase debromination. For comparison we have also produced the bowl isomer of C20 using the same procedure. We characterize the generated C20 clusters using mass-selective anion photoelectron spectroscopy; the observed electron affinities and vibrational structures of these two C20 isomers differ significantly from each other, as well as from those of the known monocyclic isomer. We expect that these unique C20 species will serve as a benchmark test for further theoretical studies.

CT-based manual segmentation and evaluation of paranasal sinuses.

Manual segmentation of computed tomography (CT) datasets was performed for robot-assisted endoscope movement during functional endoscopic sinus surgery (FESS). Segmented 3D models are needed for the robots' workspace definition. A total of 50 preselected CT datasets were each segmented in 150-200 coronal slices with 24 landmarks being set. Three different colors for segmentation represent diverse risk areas. Extension and volumetric measurements were performed. Three-dimensional reconstruction was generated after segmentation. Manual segmentation took 8-10 h for each CT dataset. The mean volumes were: right maxillary sinus 17.4 cm(3), left side 17.9 cm(3), right frontal sinus 4.2 cm(3), left side 4.0 cm(3), total frontal sinuses 7.9 cm(3), sphenoid sinus right side 5.3 cm(3), left side 5.5 cm(3), total sphenoid sinus volume 11.2 cm(3). Our manually segmented 3D-models present the patient's individual anatomy with a special focus on structures in danger according to the diverse colored risk areas. For safe robot assistance, the high-accuracy models represent an average of the population for anatomical variations, extension and volumetric measurements. They can be used as a database for automatic model-based segmentation. None of the segmentation methods so far described provide risk segmentation. The robot's maximum distance to the segmented border can be adjusted according to the differently colored areas.

SIMULATION OF OSL AND TLD DOSEMETER RESPONSE FOR THE DEVELOPMENT OF NEW EXTREMITY DOSEMETERS.

The individual monitoring service at the Helmholtz Zentrum München is currently developing a new eye lens dosemeter to be integrated in radiation protection glasses and a new ring dosemeter using a new BeOSL detector element for extremity dosimetry developed by Dosimetrics. In the design process for the new eye lens dosemeter, MCNP6 Monte Carlo simulations were used to model the energy and angular response of new dosemeters before ordering the expensive tools for injection molding. This study describes the simulation of the dosemeter and detector, and the involved calculations do obtain the response in terms of the radiation protection quantity Hp(3). Simulations were carried out also for existing whole body dosemeters and TLD rings in order to verify the MC tools. With the final dosemeter prototypes becoming available earlier this year, all MC models could be verified and show very good agreement with experimental data.

[Evaluation of force data with a force/torque sensor during FESS. A step towards robot-assisted surgery]. / Sensorbasierte Messung mechanischer Kräfte am Endoskop während FESS. Schritte zur robotergestützten Nasennebenhöhlenchirurgie.

BACKGROUND: To relieve the surgeon during functional endoscopic endonasal sinus surgery (FESS), the endoscope should be guided by autonomous robot assistance. The surgeon will thus have two hands free for suctioning and manipulation during FESS. PATIENTS/METHODS: With a force/torque sensor mounted on the endoscope, we measured forces in six degrees of freedom in five cadaver heads and in 20 actual endoscopic sinus procedures. On the cadaver heads we performed complete endoscopic endonasal dissection of all paranasal sinuses. All forces at the endoscope were monitored continuously. RESULTS: The mean forces occurring at the endoscope were 3.2 N. There were only slight differences between the in vivo and ex vivo data. We measured peak forces up to 25.2 N. In 95% of all cases, forces were lower than 7 N. CONCLUSION: Forces up to 7 N are sufficient for endoscopic guidance during FESS. Peak forces are distinctive for endoscopic guidance by humans and could be optimised by sensor-based intraoperative robot guidance. Higher forces are required for surgical endoscopy of the frontal and maxillary sinuses compared with the ethmoid sinuses.

Using robotic systems in order to determine biomechanical properties of soft tissues.

Biomechanical properties of soft tissue are important not only during computer simulation for medical training but also for systems where tissue deformation must be estimated in real-time, for example, Robot Assisted Surgery. The purpose of this paper is to describe some biomechanical tests consisting in the measurement of contact forces and deformations in tissue phantoms and porcine soft tissues (liver, brain, stomach and intestine). During the measurements two different procedures were applied. First, we have used a 5DOF micromanipulator instrumented with a spherical probe and a 6-axis force/torque ATI sensor. In the second procedure instead of the micromanipulator a Stäubli RX60 robot was used to apply the force over the samples. During this last test a high noise-signal relationship was detected and in order to improve the accuracy of the experiments some results were obtained using a Stäubli TX40 robot. Major accuracy in research in the field of soft tissue could be reached using standard procedures. Robotic systems allow precise movements to carry on biomechanical tests, and also permit a wide range of tasks to be implemented.

Robot-assisted fracture reduction: a preliminary study in the femur shaft.

Reduction in femoral shaft fractures can be difficult to achieve with minimally invasive techniques. Malalignment and high intra-operative radiation exposure can result. The hypothesis was that robot-assisted fracture reduction could improve the quality of reduction while reducing the amount of radiation exposure. A robot system was developed that allows fracture manipulation with a joystick as input device. The system provides the surgeon with haptic and metric feedback. Fifteen synthetic femurs were broken and reduced by simulated open (group A) and closed techniques (group B). These techniques were compared with the robot-assisted reduction with (group C) and without (group D) haptic and metric information. An image intensifier was simulated with two orthogonal cameras. All reduction techniques showed minor malalignment. In group C, the alignment was: procurvatum/recurvatum 0.6 degrees (0-2.0 degrees); varus/valgus 0.8 degrees (0-3.0 degrees); and axial rotation 0.8 degrees (0-3.1 degrees). A significant difference was seen between the groups (two-way ANOVA, p < 0.001). Axial rotation was significantly lower in group C than in group B (1.9 degrees; p < 0.001). The residual varus and valgus deviation was higher in group C compared with group A (0.4 degrees, p = 0.03). The median number of simulated radiographs was significantly less in group C (35) compared with group D (72; p < 0.001) and group B (49; p = 0.01). Robot-assisted fracture reduction of the femur provides high precision in alignment while reducing the amount of intraoperative imaging. Further research in this field is worthwhile.

Enoxaparin in experimental stroke: neuroprotection and therapeutic window of opportunity.

BACKGROUND AND PURPOSE: Heparin and heparinoids have long been proposed for stroke treatment. This study investigates the effect of enoxaparin (Lovenox, Clexane), a low-molecular-weight heparin, on functional outcome (neuroscore) and lesion size in stroke models with reversible and irreversible cerebral ischemia using middle cerebral artery occlusion (MCAO) in the rat. METHODS: Ischemia was induced in rats by transient occlusion for 2 hours or by permanent electrocoagulation of the left MCA. Forty-eight hours after ischemia, neurological deficit was evaluated by scoring sensorimotor functions and ischemic damage was quantified by histological evaluation of lesion volumes. RESULTS: After transient MCAO, enoxaparin at 2x1.5 mg/kg IV (2 and 24 hours after insult) significantly reduced lesion size by 30% (P<0.05) and improved neuroscore (P<0.01). This significant effect on lesion size and neuroscore was still evident when treatment was started 5 hours after insult. Administered under the same protocol with a 5 hours delay post permanent MCAO, enoxaparin reduced lesion size by 49% (P<0.05) and improved neuroscore (P<0.01). CONCLUSIONS: This study indicates that standard nonhemorrhagic doses of enoxaparin reduce ischemic damage with a wide therapeutic window. In addition to its anticoagulant properties, other properties of enoxaparin could act in synergy to explain its neuroprotective profile in ischemia. Thus clinical application of enoxaparin treatment in stroke warrants serious consideration.

Time course of cerebral edema after traumatic brain injury in rats: effects of riluzole and mannitol.

Brain trauma is the main cause of morbidity and mortality in young adults. One delayed events that occurs after a head trauma and compromises the survival of patients is cerebral edema. The present study examined first the occurrence of cerebral edema after a traumatic brain injury (TBI) induced by moderate fluid percussion in rats. Brain water content was measured from 1 h to 7 days posttrauma, in the hippocampus and cortex, on both ipsi- and contralateral hemispheres. Second, the effects of mannitol, an osmotic agent frequently used in the clinic, and riluzole, a neuroprotective compound, were investigated on regional edema formation. After TBI, the ipsilateral edema began early at 1-6 h, was maximal at 48 h and was resorbed by 5-7 days. No edema was observed in the contralateral hemisphere. Mannitol at 1 g/kg or vehicle was administered iv 15 min, 2 h and 4 h postinjury. At this dose, mannitol significantly attenuated the ipsilateral injured cortex edema measured at 6 h (p < 0.05). Riluzole at 4 and 8 mg/kg or vehicle was administered 15 min (IV) and 6 h, 24 h, and 30 h (SC) post-TBI. Riluzole at 4 x 4 mg/kg significantly reduced edema measured at 48 h, in the ipsilateral hippocampus (p < 0.05), whereas at 4 x 8 mg/kg, the reduction was observed in the hippocampus (p < 0.01) and the injured cortex (p < 0.05). Our results demonstrate that (1) cerebral edema begins early after the injury and is resorbed over 1 week; (2) mannitol could attenuate cerebral edema; and (iii) riluzole in addition to its neuroprotective effects reduces the brain edema. Thus, riluzole could be useful in human TBI treatment.

Enoxaparin reduces brain edema, cerebral lesions, and improves motor and cognitive impairments induced by a traumatic brain injury in rats.

Traumatic brain injury (TBI) is often accompanied by secondary ischemia due, in part, to edema-induced blood vessel compression. Enoxaparin, a low-molecular weight heparin, which is efficacious in models of myocardial and brain ischemia was studied in lateral fluid percussion-induced TBI in rats. Enoxaparin was administered 2 h post-TBI at 0.5 mg/kg i.v. followed by 4 x 0.5, 4 x 1, or 4 x 2 mg/kg s.c. over 30 h. Brain edema was measured in the hippocampus, temporal cortex and parietal cortex. Edema was reduced by enoxaparin (0.5 + 4 x 0.5 mg/kg) in the hippocampus (-53%, p = 0.07) and the parietal cortex (-39%, ns). At 0.5 + 4 x 1 mg/kg edema was reduced in the hippocampus (-63%, p < 0.05) and the parietal cortex (-47%, p = 0.06). At 0.5 + 4 x 2 mg/kg, the reduction was more important in the hippocampus (-69%, p < 0.01) and in the parietal cortex (-50%, p < 0.05). No reduction was seen in the temporal cortex. The lesion size was reduced by enoxaparin at 0.5 + 4 x 1 mg/kg (-50%, p < 0.05), and at 0.5 + 4 x 2 mg/kg (-35%, ns). The neurological deficit evaluated with a 9-point scale was also improved with enoxaparin at 0.5 + 4 x 1 mg/kg 1 week post-TBI (p < 0.05). The cognitive impairment evaluated with a Lashley maze task was improved with enoxaparin (0.5 + 4 x 1 mg/kg) from 48 h (p < 0.05) to 2 weeks post-TBI (p < 0.01). Our results demonstrate for the first time that enoxaparin significantly reduces the brain contusion and edema, and improves the functional outcomes induced by a TBI. Therefore, enoxaparin could be a candidate drug to treat acute brain-injured patients.

Kinetics of polymorphonuclear neutrophil infiltration after a traumatic brain injury in rat.

The aim of our study was to assess polymorphonuclear neutrophil infiltration into the injured parenchyma after a traumatic brain injury (TBI). Myeloperoxidase (MPO) activity was assayed on the hippocampus, temporal and parietal cortex 6, 24, 48, 72, and 120 h post-trauma. MPO activity occurred in these structures from 6 h post-trauma and was maximum at 24-48 h. It was resolved by 72 h in the hippocampus and the parietal cortex, but persisted in the temporal cortex until 120 h after trauma. This suggests that neutrophil infiltration is a delayed phenomenon in the physiopathology of TBI. Considering that a large therapeutic window may be crucial in the management of TBI, inhibition of neutrophil infiltration needs to be further investigated following cerebral trauma.

Involvement of dopaminergic receptors in quinolinate-induced striatal lesions.

The purpose of this study was to examine the effects of blockade (sulpiride) and activation (quinpirole) of dopaminergic D2 (DA2) receptors on brain lesions subsequent to excessive activation of glutamate (GLU) receptors. Striatal lesions were produced by direct injection of quinolinic acid, an endogenous GLU receptor agonist. Sulpiride (100 mg kg-1 i.p., 30 min before quinolinic acid injection and 1 h after) significantly (p < or = 0.05) reduced the volume of the lesion by around 20%. Quinpirole (1.25 mg kg-1 i.p., 30 min before quinolinic acid injection) had no effect. The protective action of DA2 receptor blockade strongly suggests that quinolinic acid-induced excitotoxicity may be partly modulated by DA2 receptors.

Riluzole reduces brain lesions and improves neurological function in rats after a traumatic brain injury.

Riluzole (2-amino 6-trifluoromethoxy-benzothiazole) was studied in a rat model of traumatic brain injury (TBI) induced by a fluid percussion applied laterally to the right parietal cortex. Study I: vehicle or riluzole (4 or 8 mg/kg) was administered 15 min (i.v.), 6 h and 24 h (s.c.), after TBI. Brain lesions were quantified 1 week after insult. Riluzole significantly reduced the size of TBI-induced lesions by approximately 44% with either dose regime (P < 0.05). Study II: vehicle or riluzole (8 mg/kg) was administered 15 min (i.v.), 6 h (i.p.) and then twice daily (i.p.) for 6 days, after injury. One, 2 and 3 weeks after TBI, a neurological examination was performed. Control injured rats had a significant neurological deficit at 1, 2 and 3 weeks (P < 0.001). Riluzole treatment did not modify the neurological status evaluated for the first 2 weeks after TBI. However at 3 weeks, riluzole significant improved the neurological function of injured rats (P < 0.05). These results suggest that riluzole may be beneficial in the clinical treatment of TBI. The protective action of riluzole may result from (i) stabilization of the inactivated state of voltage-dependent sodium channels, (ii) indirect action on the glutamatergic pathway, and/or (iii) indirect neurotrophic effect.

Effect of riluzole on focal cerebral ischemia in rats.

The effects of riluzole, a putative inhibitor of glutamate release, on the histological and neurobehavioral consequences of middle cerebral artery occlusion were tested in Sprague-Dawley rats. Neurobehavioral studies (neurological examination, passive avoidance task) were carried out with sham-operated and occluded rats. Riluzole 4 and 8 mg/kg administered 30 min after occlusion reduced (P < 0.01) the cortical infarct (respectively 94 +/- 12 mm3 and 73 +/- 15 mm3 versus 139 +/- 8 mm3 for control rats). Striatum necrosis was not modified by the low dosage (46 +/- 3 mm3 versus 49 +/- 3 mm3 for control rats), whereas the high dosage increased it (61 +/- 3 mm3, P < 0.05). The ischemia-induced neurological and memory impairments were not improved by riluzole. Our results indicate that a drug depressing glutamatergic neurotransmission without blocking the glutamate receptors exerts anti-ischemic activity. Moreover, the results highlight the need for carrying out histological and neurobehavioral studies in parallel in this model.

Effect of riluzole on quinolinate-induced neuronal damage in rats: comparison with blockers of glutamatergic neurotransmission.

Intrastriatal injection of quinolinate, an N-methyl-D-aspartate (NMDA) agonist, induces a local neuronal lesion, and provides an excitotoxic model of Huntington's disease. In this study, we investigated the effect of different agents acting at various levels of the glutamatergic neurotransmission: (i) dizocilpine (MK801) (0.5 mg/kg ip) significantly reduced the lesion by 74%; (ii) 6-(1-imidazolyl)-7-nitroquinoxaline-2,3(1H,4H)-dione (YM-90K) (3 x 10 and 3 x 20 mg/kg ip) and (iii) lamotrigine (50 mg/kg ip) had no effect; (iv) riluzole (4 and 8 mg/kg per os) significantly reduced the lesion by 35%. The inefficiency of YM-90K suggested that alpha-amino-3-hydroxy-5-methylisoxasole-4-propionate (AMPA) receptors do not participate to the quinolinate-induced excitotoxicity. The mechanism of action of riluzole may be related also to a combination of its different properties. This study indicates that riluzole may be useful for treatment of Huntington's disease.

Influence of anesthesia protocol in experimental traumatic brain injury.

Most pharmacologic studies on brain trauma in animals are performed while the animals are under general anesthesia, which can interfere with brain metabolism and modify the experimental results. This study investigates the effects of three anesthetic drugs (halothane 2% and 4%, propofol at 10 mg/kg, and chloral hydrate at 400 mg/kg) on the traumatic brain injury-induced neurologic deficit in mice. Trauma was induced with a weight-drop device. For each drug, animals were divided into four groups; the first did not receive either anesthesia or trauma, the second received anesthesia but no trauma, the third received a trauma without anesthesia, and the fourth received anesthesia before the trauma. A neurologic examination using two different scorings (string and grip test) was performed 1 hour and 24 hours after the trauma. Mortality after trauma was increased for halothane 4% (48% versus 20% in unanesthetized mice), propofol (80% versus 30%), and chloral hydrate (70% versus 44%). Halothane 2% did not increase the mortality in traumatized mice. Halothane 2% or 4% anesthesia did not modify the string score after the trauma. Grip score after the trauma was better in mice anesthetized with halothane at either 2% or 4%. Mice injured under anesthesia with chloral hydrate had worse grip and string scores (P < .05) than unanesthetized mice. These results lead us to question the influence of anesthesia on the results obtained in experimental neuropharmacologic studies, particularly when there are discrepancies between two studies on the same pharmacologic treatment, which differ in their anesthesia protocols.

Vector-entropy optimization-based neural-network approach to image reconstruction from projections.

In this paper we propose a multiobjective decision making based neural-network model and algorithm for image reconstruction from projections. This model combines the Hopfield's model and multiobjective decision making approach. We develop a weighted sum optimization based neural-network algorithm. The dynamical process of the net is based on minimization of a weighted sum energy function and Euler's iteration, and apply this algorithm to image reconstruction from computer-generated noisy projections and Siemens Somatson DR scanner data, respectively. Reconstructions based on this method is shown to be superior to conventional iterative reconstruction algorithms such as the multiplicate algebraic reconstruction technique (MART) and convolution from the point of view of accuracy of reconstruction. Computer simulation using the multiobjective method shows a significant improvement in image quality and convergence behavior over the conventional algorithms.

Neuroprotective effects of riluzole in neurotrauma models: a review.

Physical injury to the central nervous system (CNS) remains one of the main causes of mortality and disability in young adults. Numerous therapies have been successfully evaluated in experimental traumatic brain or spinal cord injuries (TBI, SCI) and, although some of them are currently under clinical trials for these indications, no drug therapy is at present available. Thus, an interesting approach to reduce the CNS injury-induced damage could be the blockade of Na(+)-channels by drugs such as riluzole which is neuroprotective in models of TBI or SCI as summarized in this review. Repeated doses ranging from 2 to 8 mg/kg were administered between 24 h to 10 days post-injury, with a first administration given either at 15 min or up to 6 h post-injury. In these models riluzole was found to reduce both the size of spinal cord and brain lesions as well as brain edema, and to restore the neurological, motor and cognitive impairments consequent of these injuries. The largest therapeutic time window obtained was 1 to 6 h in TBI. This such a compound should be considered as an interesting candidate for the treatment or SCI or TBI.

Atlas of hepatic arterial perfusion scintigraphy.

Tc-99m MAA intra-arterial perfusion studies are necessary to determine blood flow distribution for hepatic arterial chemotherapy. In this mini-atlas, examples selected from over 900 cases to illustrate important points to aid in a better understanding and interpretation of these studies with particular emphasis on diagnostic and therapeutic interventions are presented.