Non-invasive imaging

image of Non-invasive imaging
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A thorough physical examination of reptiles can be challenging. Consequently, diagnostic imaging is an important aspect of the health evaluation of reptiles. This chapter describes the four types of non-invasive imaging techniques that are used for reptiles: Radiography, Ultrasonography, Computed tomography (CT) and Magnetic resonance imaging (MRI).

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9.1 (a) Digitalized dorsoventral and (b) reverse-contrast radiographs of a red-eared terrapin with an aural abscess. Soft-tissue swelling and lysis of the left squamosal bone is visible.
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9.2 A dental X-ray unit being used to radiograph the foot of a bearded dragon. Note the sensor enclosed in a protective transparent sleeve that is positioned under the foot.
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9.4 For a horizontal lateral radiograph, this Chinese box turtle is immobilized on a raised platform. The X-ray plate is behind the turtle.
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9.5 Dorsoventral radiograph of a normal gravid eastern box turtle. 1 = humerus; 2 = acromion; 3 = coracoids; 4 = vertebral column; 5 = pubis; 6 = obturator foramen; 7 = ischium; 8 = femur; 9 = egg; 10 = plastral hinge.
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9.6 Dorsoventral radiograph of the skull of a normal mata mata turtle illustrating the well developed hyoid apparatus. 1 = first branchial horn; 2 = second branchial horn.
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9.7 Left lateral radiograph of a normal Malayan box turtle. 1 = plastron; 2 = ilium; 3 = carapace; 4 = vertebral column; 5 = cervical vertebrae; 6 = scapula; 7 = skull; 8 = orbit; 9 = lungs; 10 = viscera.
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9.8 Dorsoventral radiograph of a normal spiny-tailed lizard. 1 = mandible; 2 = humerus; 3 = radius; 4 = ulna; 5 = heart; 6 = lung; 7 = intestines; 8 = femur; 9 = tibia; 10 = ischium.
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9.9 Right lateral radiograph of a normal green iguana. 1 = trachea; 2 = heart; 3 = lungs; 4 = liver; 5 = stomach with ingesta; 6 = small intestine; 7 = fat deposits; 8 = pubis; 9 = ischium; 10 = ilium.
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9.10 (a) The calcified endolymphatic sacs are easily visualized in this defensive female Moorish gecko on physical examination. (b) Note the radiopaque deposits of calcium on a dorsoventral radiograph of the same gecko.
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9.11 Right lateral radiographs of the cardiovascular and respiratory systems of a normal common boa: (a) 1 = trachea; 2 = heart; 3 = lung; 4 = spine and ribs; (b) X = air sac.
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9.12 Right lateral radiographs of (a) the calcified hemipenes (arrowed) and (b) hyoid apparatus (arrowed) of a normal adult indigo snake. Note the trachea (radiolucent stripe) coursing just dorsal to the hyoid bones.
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9.13 (a) Dorsoventral radiograph of soft-tissue swelling of the right femur of a green iguana. (b) Transverse view of the encapsulated granuloma (*) from the same iguana after euthanasia.
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9.14 (a) Dorsoventral radiograph of a red-eared terrapin with polyarticular gout. Note the mixed pattern of lysis and mineralized proliferative changes of the stifle and both hock joints. (b) Needle-like urate crystals aspirated from the affected stifle joint.
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9.15 Dorsoventral radiograph of a Central American wood turtle with articular and periarticular mineralized opacities of the left stifle joint. A diagnosis of calcinosis circumscripta was based upon biopsy of the affected joint.
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9.16 Right lateral radiograph of a Burmese python with severe soft-tissue swelling of the cervical area that was associated with a bacterial infection. Note the trachea (radiolucent stripe) and calcified tracheal rings.
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9.17 (a) Deformities of the caudal spine of a juvenile chondropython with a prolapsed cloaca. (b) Right lateral radiograph of the same snake. Note multiple DV curvatures of the axial skeleton consistent with kyphosis.
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9.18 Right lateral radiograph of a Burmese python with faecal retention. Note the presence of multiple irregularly shaped radiopaque densities containing foreign material within the large intestine. The snake had been maintained at suboptimal temperatures.
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9.19 (a) Dorsoventral radiograph of the right elbow joint of a geriatric green iguana. Note extensive periarticular osteophyte formation and joint swelling (arrowed). (b) Right lateral radiograph of a geriatric green iguana with ankylosing spondylopathy. There is new bone formation on the ventral margins of multiple coccygeal vertebrae. Note fractures of the dorsal vertebral process and body of a coccygeal vertebra below the radiopaque marker.
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9.20 (a) Preovulatory follicular development in a juvenile veiled chameleon. Soft-tissue spherical densities are present in the caudal coelom. Note the generalized rarefied skeletal anatomy consistent with nutritional secondary hyperparathyroidism. (b) An emerald tree boa with distension of its mid-body due to enlarging ovaries. (c) Right lateral radiograph of the same snake with soft-tissue spherical densities consistent with follicular development.
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9.21 Dorsoventral radiographs of normal gravid reptiles: (a) indigo snake; (b) bearded dragon; (c) calcified fetal skeletons during late-stage pregnancy in a crocodile lizard.
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9.22 (a) Dorsoventral radiograph of a gravid red-footed tortoise. In addition to normal eggs, there is a large comma-shaped egg that has been retained as evidenced by excessive mineralization of its shell. (b) Right lateral radiograph of a gravid kingsnake with an excessively large retained egg.
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9.23 Right lateral radiograph of a diamond python with oesophagitis. The snake had been force-fed by the owner several times and began regurgitating shortly thereafter. A barium swallow revealed filling defects of the proximal oesophagus consistent with oesophageal erosions.
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9.24 (a) Dorsoventral radiograph of a leopard tortoise that presented with anorexia of 3-weeks’ duration. The small and large intestines are dilated with excessive amounts of gas consistent with ileus. (b) Necropsy revealed a mesenteric volvulus (arrowed).
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9.25 Dorsoventral radiograph of a double-contrast study of the stomach and duodenum of a normal African spurred tortoise. Note the presence of gas in the gastric lumen (*) and smooth outline of contrast in the fundus. In the small intestine the barium has a ‘brush’ appearance due to the presence of villi. There is a peristaltic wave in the proximal duodenum.
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9.26 (a) Dorsoventral radiograph of a 50% sodium diatrizoate contrast study of a red-eared terrapin that presented with vomiting of 2-weeks’ duration and a prolapsed penis. There is stasis of contrast in the transverse colon 14 days post administration (*). (b) Necropsy revealed a stricture of the descending colon, presumably due to ingestion of a sharp foreign object (arrowed).
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9.27 Right lateral radiograph of barium contrast in the colon of a green tree python that had a prolapsed cloaca. Orad movement of contrast into the colon confirms that the cloaca had been properly replaced inside the coelom.
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9.28 Dorsoventral radiograph of a Texas tortoise that was constipated due to lithophagy. Multiple radiopaque foreign bodies are located in the lower intestines. Treatment consisted of daily soakings in water and mineral oil administered via gastric tubing.
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9.29 (a) Dorsoventral (DV) radiograph of a leopard tortoise that was dropped by the owner. There is a diaphyseal fracture of the right femur (arrowed). Immobilization of the fracture was accomplished with a coaptive splint. (b) DV  radiograph of the healed right femur 18 months later. Note the angular deformity at the healed fracture site. (c) Right lateral and (d) DV  radiographs of a black ratsnake that sustained trauma following a fall. Note the fracture/separation (arrowed and arrowhead) of the dorsal aspect of a vertebral body.
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9.30 (a) Right lateral and (b) dorsoventral radiographs of a green iguana that presented with 7 days of anorexia. Note areas of increased opacity due to the presence of pockets of fluid (*) that are having a mass effect upon and obscuring the coelomic viscera. Further exploration revealed coelomitis secondary to a perforating granuloma of the small intestine.
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9.31 (a) Vertical lateral radiograph of a juvenile red-footed tortoise with multiple pulmonary soft-tissue opacities. (b) Vertical craniocaudal radiograph reveals lower respiratory tract disease (LRTD) of both lungs. A combination of parenteral antibiotics and nebulization resolved the disease. (c) Dorsoventral radiograph of a savannah monitor with left-sided pulmonic infiltrates consistent with LRTD. A pure culture of spp. was cultured. (d) Right lateral radiograph of LRTD in a Burmese python. X = loculated pockets of exudates in the air sac.
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9.32 Dorsoventral radiograph of a green iguana with metastatic mineralization of the aortic arches (arrowed and inset). Note the radiopaque outlines of the vascular intimal linings due to calcium deposition.
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9.33 (a) Dorsoventral and (b) right lateral radiographs of a 3-year-old bearded dragon that was presented with a 2-week history of lethargy and anorexia. Note the presence of an opaque coelomic soft-tissue mass on both views (*). Histopathological diagnosis was gastric neuroendocrine carcinoma. (c) A mixed pattern of lytic and osteoproliferative changes of the vertebrae are present in this 35-year-old kingsnake. Histopathological diagnosis was fibrosarcoma. (a, b, Courtesy of Bruce Levine)
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9.34 (a) Gross appearance of the left hindlimb of a bearded dragon that was bitten by a green iguana 3 weeks prior to presentation. (b) Dorsoventral radiograph of the chronically affected limb revealing lysis and expansion of cortical bone of the distal femur and proximal tibia. Bacteria isolated were a coagulase-positive and .
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9.35 Right lateral radiograph of an adult green iguana with vertebral osteomyelitis. Note the presence of proliferative changes and bridging of the ventral aspects of the vertebral bodies with new bone (compare radiographic similarities to Figure 9.19b ). A coagulase-positive infection was diagnosed based upon culture from a bone biopsy specimen.
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9.36 (a) Right lateral radiograph of an adult iguana that presented with a history of gradual onset of neurological deficits that progressed to quadriparesis. Note bony irregularities and increased spinal opacification at the fourth cervical vertebra (arrowed). (b) Contrast myelography (iohexol) revealed obstruction of contrast flow at C4. (Courtesy of Steven Divers)
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9.37 (a) Dorsoventral radiograph of an adult green iguana. Note two soft-tissue opacities (*) in the caudal coelom. (b) Transverse ultrasonographic image revealing bilateral renomegaly. The probe had been placed against the sublumbar fossa.
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9.38 Dorsoventral radiograph of an adult green iguana with a radiopaque calculus in the urinary bladder. Note the concentric laminations that formed as the urolith enlarged over time.
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9.40 (a) Gross appearance of a soft-tissue mass that gradually developed on a 2-year-old bearded dragon. (b) Ultrasonographic appearance revealing a heterogeneous mass consisting of a central core of hyperechoic material surrounded by anechoic fluid (*). The diagnosis was an aneurysm. (c) Ultrasonographic appearance of the gastric neuroendocrine carcinoma shown in Figure 9.33a–b . Note the homogeneous appearance to this solid mass (*) and shadows produced by the ribs. (d) Left lateral radiograph of an adult bearded dragon that presented with anorexia and dyspnoea. A soft-tissue opacity in the cranial coelom (black *) is causing a mass effect on the lungs (white *). (e) Ultrasonography revealed cardiomegaly secondary to pericardial effusion (PE). Note the presence of anechoic fluid surrounding the heart. LA = left atrium; V = ventricle. (c, Courtesy of Bruce Levine)
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9.41 Ultrasonographic image of a hyperechoic mass attached to the posterior globe in an asymptomatic adult green iguana. This was suspected to be a hyaline remnant or blood vessel. PC = posterior chamber.
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9.42 (a) Dorsoventral radiograph of an anorexic adult female iguana with opacification of the caudal coelom, which is producing a mass effect upon the intestines. (b) Ultrasonographic appearance of irregularly shaped preovulatory follicles in various stages of development from the same lizard. Note that some contain anechoic fluid while others possess hyperechoic contents. Oophoritis was diagnosed. (c) Postsurgical appearance of the excised necrotic ovaries. (d) Ultrasonographic appearance of atretic follicles in a green iguana. Note multiple irregularly shaped hyperechoic structures marked with calipers.
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9.43 Ultrasonographic appearance of a plastic foreign body in the stomach of a green iguana. Note the distal shadow caused by the inability of the ultrasound waves to penetrate the object.
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9.45 Ultrasound transducer placement. (a) Placing the transducer on the right cervical window of chelonians permits visualization of the thyroid gland, heart, liver and gall bladder. (b) To visualize organs in the caudal coelomic cavity (kidneys, urinary bladder, ovaries, testes, gastrointestinal tract) the transducer is placed on either inguinal window. (c) Placement of the transducer against the caudal lateral coelomic wall of lizards permits visualization of the urogenital and gastrointestinal systems. (d) Snakes are imaged by placing the transducer against the lateral or ventral coelomic wall.
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9.46 Normal ultrasound image of the chelonian heart through the right cervical window. LA = left atrium; PT = pulmonary trunk; RA = right atrium; T = thyroid gland; VC = ventricular chamber.
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9.47 Ultrasound image of a mediastinal granuloma (cross-arrowed) in a Chinese box turtle. The spherical encapsulated homogeneous mass was just cranial to the heart and visualized through the left cervical window.
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9.48 Ultrasound image of a normal right hepatic lobe of a chelonian acquired through the right cervical window. GB = gall bladder; PVC = posterior vena cava.
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9.49 Ultrasound image of the left hepatic lobe of a chelonian acquired through the left cervical window. Note the hyperechoic densities devoid of shadows within the liver parenchyma; differentials include fibrosis, granulomas or visceral gout; biopsy revealed gout tophi.
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9.50 Ultrasound image from an inguinal window showing vitellogenic follicles in a diamondback terrapin. The urinary bladder (UB) has enhanced the appearance of the hyperechoic spherical follicles (arrowed).
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9.51 Ultrasound image from an inguinal window showing the hyperechoic plicated oviduct (*) in an impressed tortoise.
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9.52 Ultrasound image of the homogeneous triangular kidney (arrowheads) of a yellow-footed tortoise. Note the hypoechoic vasculature. The image was visualized through the left inguinal fossa.
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9.53 (a) Ultrasonographic appearance of increased echogenicity of the epicardial lining and atrioventricular valves of the heart, due to deposition of urate crystals in a green iguana. (b) Hyperechoic changes to the intimal linings of the aorta and endocardium of a green iguana (see Figure 9.32 ) diagnosed with metastatic mineralization. AO = aorta; VC = ventricular chamber.
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9.54 (a) Ultrasonographic appearance of the normal liver of a savannah monitor. Note the homogeneous appearance of the parenchyma and the gall bladder (GB) containing anechoic bile. (b) Normal ultrasound image of the caudal vena cava (VC) exiting the liver and entering the right atrium of a green iguana; note the echogenic walls of the vena cava. HT = heart; LIV = liver. (c) Ultrasound image of a biliary duct carcinoma in a savannah monitor. The liver parenchyma (1) has been displaced by anechoic cavitations (2) that are lined with neoplastic cells. Note the presence of hyperechoic distal reverberations due to air from the lung.
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9.55 Normal ultrasound image of the terminal part of the large intestine (LI) and cloaca (CL) of a savannah monitor. Both organs contain anechoic fluid. Note the dorsal hyperechoic mucosal fold partially separating the cloaca from the large intestine.
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9.56 (a) Ultrasound image of a quiescent ovary in a green iguana. The cortex (1) contains small anechoic follicles. The echogenic medulla (2) contains connective tissue and blood vessels. (b) Ultrasound image of an active ovary containing enlarged anechoic vitellogenic follicles in a green iguana. (c) Ultrasound image of egg yolk coelomitis in a green iguana. The hyperechoic exudate prevents visualization of other organs.
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9.57 Ultrasound image of a gravid green iguana. Note the irregular shapes of the hyperechoic shell membranes of the eggs.
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9.58 Ultrasound image of the spherical testis (cross-arrowed) in a green iguana. There is a small amount of anechoic fluid surrounding the testis, which is normal. Note that the testis possesses a hyperechoic capsule and is less echogenic than the surrounding fat.
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9.59 (a) Ultrasound image of the tail base of a male prehensile-tailed skink. The heterogeneous structure (arrowed) is the hemipenis. (b) Note the absence of this structure in the tail base of a conspecific female.
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9.60 (a) Ultrasound image of the cranial poles of the kidneys (arrowheads) of a green iguana in ventral recumbency. There is increased echogenicity to the renal parenchyma due to urate infiltration. The probe has been placed on the sublumbar area and angled caudally towards the pelvic inlet. (b) Ultrasound image of metastatic calcification in the kidney of a green iguana: 1 = mineralized deposit; 2 = shadow created by calcium phosphate complex; 3 = ischium; 4 = shadow created by bone. (c) Adipose tissue of a well nourished royal python. Note the hyperechoic septum separating two fatty lobes.
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9.61 Ultrasound image of the anechoic gall bladder (GB) filled with bile in a royal python: 1 = fat; 2 = rib shadow.
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9.62 Longitudinal ultrasound image of the small intestine in a Solomon Island boa. The hyperechoic stripe is the lumen, which contains chyme. In this picture, the walls of the intestine are anechoic.
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9.63 (a) Ultrasound image of two homogeneous vitellogenic follicles (1 and 2) in a Solomon Island boa. As follicles develop, they increase in echogenicity due to yolk formation. Compare the relative echogenic characteristics of the follicles, fat (3) and gall bladder (GB). (b) Ultrasound image of an ovarian tumour (cross-arrowed) of mixed (heterogeneous) echogenicity in a corn snake: 1 = capsule of tumour. (c) Ultrasound image of an Asian ratsnake egg; note the hyperechoic shell membranes surrounding hypoechoic yolk. (d) Ultrasound image of Solomon Island boa fetuses; note the distal shadowing created by the fetuses.
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9.64 Ultrasound image of normal renal parenchyma in a Honduran milk snake. Note the more heterogeneous appearance compared with the kidney of a yellow-footed tortoise in Figure 9.52 .
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9.65 (a) Transverse CT image of the lungs of a leopard tortoise. Note the reticular pattern of normal lung parenchyma (inset). (b) Transverse CT image demonstrating unilateral folliculogenesis in a musk turtle that had buoyancy problems: 1 = normal lung; 2 = lung with compression due to follicles; 3 = vitellogenic follicles. (c) Transverse CT image of a leopard tortoise with hepatic dystrophic mineralization (1) and vitellogenic follicles (2).
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9.66 (a) Single photon emission computerized tomographic (SPECT) image of a 1 miCi technetium scan at 15–45 minutes of a normal leopard gecko, with thyroxine of 6.05 nmol/l. Technetium mimics iodine; note the normal bilateral thyroid glands (arrowed) ventral to the cervical vertebrae. (b) SPECT image of a 1 miCi technetium scan at 15–45 minutes in a hyperthyroid leopard gecko, with thyroxine of 64.35 nmol/l. The single midline focus of increased uptake is thought to be the overactive thyroid gland (arrowed); the contralateral gland is not visible because of negative feedback and atrophy. (Courtesy of Thomas Boyer, Seth Wallack, Ann Bettencourt and Mario Bourdon)
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9.67 (a) Axial T1- and T2-weighted magnetic resonance (MR) images of an adult female red-eared terrapin: 1 = developing follicles; 2 = loops of intestine; 3 = liver; 4 = gall bladder; 5 = stomach. (b) Coronal T1-weighted MR image of the head of an Asian water monitor at the level of the orbits: 1 = vitreous humour; 2 = cornea; 3 = eyelid; 4 = aqueous humour; 5 = lens; 6 = forebrain; 7 = auditory canal; 8 = optic nerve. (c) Transverse T1-weighted MR image of the kidneys (arrowed) of an adult impressed tortoise. (d) Sagittal T1-weighted MR image of the head of an Asian water monitor at the level of the brain: 1 = olfactory bulbs; 2 = glottis; 3 = pituitary gland; 4 = diencephalon; 5 = trachea; 6 = spinal cord; 7 = cerebellum; 8 = pineal gland; 9 = cerebrum. (a, Courtesy of Noemie Summa; c, d, Courtesy of Robert Wagner)
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9.68 (a) Coronal T1-weighted magnetic resonance (MR) image of the head of a water monitor with gadolinium contrast enhanced angiography. The contrast agent was injected into the coccygeal vein and images were taken approximately 2 minutes later: 1 = external carotid artery; 2 = internal carotid artery; 3 = caudal cerebral artery. (b) Reverse-contrast MR image of the same reptile. (Courtesy of Robert Wagner)

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