كتاب متميّز
Introduction
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Porta hepatis: |
1 inferior vena cava, 2 liver veins, 3 portal vein, 4 splenic vein, 5 common bile duct, 6 superior mesenteric vein; liver segments |
3.1.5 Pathology (selected)
The
tubular structures of vessels containing blood and bile can be
influenced by
-
changes
in liquid pressure (resulting in a more or less pronounced
increase in vessel diameter),
-
changes
in the wall structure (e.g.,sclerosis, partial thrombosis, or
inflammation,
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occlusion
(complete thrombosis, tumor, concretions), or by
-
compression
(tumor, lymphoma, inflammation).
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1 Thoracoabdominalaneurysma, |
1 Infrarenal aneurysma, |
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1 Single arteriosclerotic plaque, infrarenal abdominal aorta (longitudinal scan) |
1 Lumen of a giant infrarenal aneurysma, 2 thrombotic portions (transverse ! scan) |
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Right heart failure with 1 dilated cava inferior and 2 dilated hepatic veins (right subcostal scan) |
1 Multiple plaques, abdominal |
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1 cava inferior with 2 tumor spread (thrombus-like) in renal adenocarcinoma 3 caudate lobe (longitudinal scan) |
Membranous dissection of abdominal aorta with 1a, 1b lumen portions and 2 dissection membrane (transverse scan) |
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1 thrombosis of left iliacal vein (no colour flow), 2 iliacal artery (left lower abdominal scan) |
1 thrombosis of superior mesenteric vein (no colour flow), 2 aorta (longitudinal scan) |
3.2. Lymphnodes and lymphoma
With the advent of more sophisticated ultrasound devices even normal paravascular lymphnodes in the abdomen may be visible in slim patients. Routinely however only enlarged lymphnodes (either benign or malignant) can be detected, usually adjacent to the great vessels (aorta, celiac axis, inferior vena cava). They are less pronounced in the liver hilum. The spleen - as a specifically big lymphnode - deserves special attention (see 3.7.).
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1, 2 lymhnodes adjacent to 3 head of pancreas, 4 splenic vein, 5 superior mesenteric artery (transverse scan) |
1 multiple lymphnodes, 2 liver, 3 aorta, 4 vertebral body, 5 celiac axis with 6 hepatic and 7 splenic artery (transverse scan) |
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arrow: retroaortal lymphnode enlargement (metastatic), 1 abdominal aorta, 2 celiac axis, 3 superior mesenteric artery, 4 liver, arrowhead: left kidney vein (longitudinal section) |
1 multiple lymphnodes anterior and posterior to 2 aorta (longitudinal scan) |
3.3. Pancreas
3.3.1. Gross (macroscopic) anatomy
The pancreas appears as a more or less carrot-shaped organ without a capsule lying transversely across the aorta and the spinal column. Its main portion - the head - is generally to the right of the second lumbar vertebra. The junction of the head and the body is curved around the vertebral column and the abdominal aorta and the tail lies in the left upper abdomen touching the splenic hilum.
The uncinate process as a part of the pancreatic head surrounds the superior mesenteric vein. The head of the pancreas itself is surrounded by the duodenal C-loop, and penetrated by the intrapancreatic portion of the common bile duct.
The pancreas is covered by intestinal structures (stomach, small and large intestine) and the left lobe of the liver. The latter serves – in deep inspiration - as an acoustic window.
3.3.2. Examination technique and ultrasound sectional anatomy
With the scanning probe in a transverse position high up in the epigastrium, a deep inspiration will move the liver downwards for some 3-5 cm, which in turn will deflect interfering gas-containing intestinal structures. The main anatomical landmarks used for visualising the pancreas are the mesenteric vascular structures which adhere to it, the splenic and mesenteric vein and their junction ( the confluens), forming the portal vein. In gross anatomy, there are no fixed demarcations between the three portions of the pancreas (head, body and tail), and the same is true of course on ultrasound scanning.
The visualisation of the non-distended main pancreatic duct as it passes along the body of the pancreas serves as a marker of ultrasound machines which have high resolution capabilties. The normal organ shows soft passive movements caused by aortic and venous pulsations.
The head and body of the pancreas are detectable in nearly all patients. The tail region (usually less important) is somewhat more difficult for the ultrasonographer due to its small size, angulated course (with a high variability ) and sometimes hidden position behind the gas filled gastric fundus. If necessary, filling the gastric fundus with non-sparkling water can create a good acoustic window for visualisation of the pancreatic tail.
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Dorsal view of the extrahepatic bile duct: 1 portal vein, 2 common bile duct, 3 pancreatic duct, 4 duodenum |
Ventral view of the extrahepatic bile duct: 1 portal vein, 2 common bile duct, 3 pancreatic duct, 4 duodenum |
3.3.3. Pathology
(selected)
As in all parenchymatous organs, an ultrasound examination of the
pancreas gives information relating to changes in its
-
position,
shape, and size,
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overall
reflexibility and
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vascular architecture
(with respect to the main pancreatic duct, the common bile duct, the
splenic and mesenteric vein and their junction, the confluens),
-
focal lesions,
and adjacent structures (e.g.lymphnodes).
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Acute pancreatitis with 1 swollen head of pancreas obstructing, 2 common bile duct (note 3 distended cystic duct) and 4 fluid filled duodenum, 5 hepatic artery, 6 portal vein, 7 liver, 8 right renal artery,inferior vena cava |
Acute pancreatits with 1 spotted head of pancreas and 2 too good visibility of lumen and * of wall layers of duodena C (transverse scan) |
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1 pathological fluid collection, 2 right liver lobe, 3 right perirenal fatty tissue (right lateral scan) |
1 enlarged head of pancreas (two weeks after inflammatory episode), 2 splenic vein, 3 liver (transverse scan) |
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Acute pancreatitis: diminuished delineability of pancreas, +...+ swollen duodenal wall, 1 duodenal lumen(transversescan) |
1 pancreatitis 2 liver, 3 gastric antrum, 4 superior mesenteric artery, 5 splenic vein /confluens, 6 duodenal C (transverse scan) |
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1 huge pseudocyst with 1p penetration into the 2 spleen (left lateral scan) |
1 acute pancreatitis with 2 pseudocyst and 3 splenic vein, 4 liver, 5 aorta (longitudinal scan) |
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Highly reflexible spots (probably calcifications in chronical pancreatitis) in 1 head and body of pancreas, 2 gastroduodenal and 3 superior mesenteric artery, 4 aorta, 5 cava inferior, 6 liver |
1 pseudocyst (color-artifact, no bleeding), 2 confluens, 3 gastro-duodenal artery, 4 reduced panreas parenchyma, 5 inferior cava, 6 duodenal C, 7 liver (2nd scans) |
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1 multiple pseudocysts, 2 aorta, 3 hepatic artery, 4 cava inferior, 5 liver, 6 confluens (transverse scans) |
1 chronical calcifying panreatitis (confirmed by ERCP) with slight compression of 2 portal vein/superior mesenteric vein, 3 gastroduodenal artery, 4 liver (modified longitudinal scan) |
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1 marked dilatation of main pancreatic duct in chronical inflammation with 2 reduced parenchyma, 3 confluens, 4 superior mesenteric artery, 5 aorta, 6 duodenal C, 7 gastric corpus |
1 reduced pancreas parenchyma in chronic inflammation with 2 marked duct dilatation, 3 splenic vein/confluens, 4 superior mesenteric artery, 5 hepatic, 6 gastroduodenal and 7 renal artery,8 aorta, 9 left renal vein, 10 liver (transverse scan) |
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1 pancreas tumour with 2 splenic vein, 3h head, 3b body of pancreas, 4 superior mesenteric artery, 5 aorta (transverse scan) |
+,* slightly dilated main pancreatic duct 1 confluens, 2 posterior antrum wall, 3 gastric lumen (with highly reflexible ingested material), 4 uncinate process (transversescan) |
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1 stent in the stenotic main pancreatic duct in chronic pancreatitis (note the reduced parenchyma) 2 superior mesenteric artery 3 confluens (transverse scan) |
1 tumour of pancreas head with 2 tip of fine needle for aspiration cytology; 3 gastroduodenal artery 4 liver (transverse scan) |
2. EXAMINATION TECHNIQUE AND SCANNING PLANES