常染色体隐性遗传性多囊肾病:临床、病理与影像学表现

常染色体隐性多囊肾病是一种以肾集合管和肝内胆管扩张、畸形及肝脏和肾脏纤维化为特点的遗传性疾病。高血压、肾功能不全及门静脉高压是常见的临床症状。影像学表现为肾脏增大但保持肾的外形，超声显示肾实质呈弥漫性回声，静脉肾盂造影及增强CT显示肾脏呈纹状改变。肝脏影像学表现可正常或肝内胆管扩张，门静脉高压常表现脾脏增大和门静脉曲张.     

Caroli disease: central dot sign in CT

Two adults with communicating cavernous ectasia of the biliary tract (Caroli disease) are described. Both patients had the pure form of the disease, characterized by saccular dilatation of intrahepatic bile ducts, multiple intrahepatic calculi, absence of portal hypertension, and associated cystic renal disease. Computed tomographic (CT) scans of the liver showed tiny dots with strong contrast enhancement within dilated intrahepatic bile ducts (the central dot sign). These intraluminal dots on CT scans corresponded to intraluminal portal veins on sonograms, findings indicating portal radicles surrounded by dilated intrahepatic bile ducts.     

A spectrum of renal tubular ectasia and hepatic fibrosis.

Renal tubular cystic disease and hepatic fibrosis exhibit a specific genetic pattern and pathological findings. The renal collecting tubules are dilated and the liver shows fibrosis with proliferation and dilatation of the bile ducts. The findings fall into a spectrum with marked renal disease and mild liver involvement at one end and mild renal involvement with severe liver disease at the other. Between these extremes lies an intermediate form which is genetically and pathologically similar, but exhibits a wide range of clinical and radiological findings due to the variability of renal and liver involvement.     

Sonography of infantile polycystic kidney disease

Sonography was performed on five children, ages 1 day-9 years, who had classic infantile polycystic kidney disease and on one child who had glomerulocystic renal disease. Microcystic involvement of the kidneys in infantile polycystic kidney disease results in renal enlargement, increased echogenicity of renal parenchyma but good transmission of sound through the kidney, and poor definition of renal borders on sonograms. The periportal involvement of the liver in the classic infantile polycystic kidney disease may lead to hepatic fibrosis and portal hypertension. Less typical features include asymmetric renal enlargement and macrocysts in the renal parenchyma.     

Caroli disease: high-frequency US and pathologic findings

Three infants with nonobstructive bile duct dilatation (Caroli disease) are described. The bile duct pathology was associated with autosomal recessive polycystic kidney disease in two patients and with severe destruction of the renal parenchyma of unknown origin in the other. Sonograms of the liver showed, besides bile duct dilatations, intraluminal bulbar protrusions, bridge formation across dilated lumina, and portal radicles partially or completely surrounded by dilated bile ducts. Liver biopsy was performed in two patients, and in one patient, the biopsy sample confirmed the findings noted on sonograms. These findings support the hypothesis that the normal embryogenesis of intrahepatic bile ducts is arrested in the pathogenesis of this disease.     

Caroli syndrome

In 1958 Caroli described the syndrome of congenital, either segmental or involving the entire bile duct system, saccular extensions of the intrahepatic bile ducts. He differentiated between two types of this disease pattern. The first form concerns pure cystic dilatations of the intrahepatic bile ducts, whereas the second one is combined with hepatic fibrosis and portal hypertension. Both types are characterised by cystic dilatations in the kidneys and in the extrahepatic bile ducts, pancreas and spleen.     

Imaging findings in congenital hepatic fibrosis

Congenital hepatic fibrosis (CHF) is a rare congenital multisystemic disorder, mostly inherited in autosomal recessive fashion, primarily affecting renal and hepatobiliary systems. Main underlying process of the disease is the malformation of the ductal plate, the embryological precursor of the biliary system, and secondary biliary strictures and periportal fibrosis ultimately leading to portal hypertension. The natural course of the disease is highly variable ranging from minimally symptomatic disease to true cirrhosis of the liver. However, in most patients the most common manifestations of the diseases that are related to portal hypertension, particularly splenomegaly and bleeding varices. Many other disease processes may co-exist with the disease including Caroli's disease, choledochal cysts and autosomal recessive polycystic kidney disease (ARPKD) reflecting the mulstisystemic nature of the disease. The associating biliary ductal disease led the authors to think that all these entities are a continuum and different reflections of the same underlying pathophysiological process. Although, conventional method of diagnosis of CHF is the liver biopsy the advent of imaging technologies and modalities, today, may permit the correct diagnosis in a non-invasive manner. Characteristic imaging features are generally present and recognition of these findings may obviate liver biopsy while preserving the diagnostic accuracy. In this article, it is aimed to increase the awareness of the practising radiologists to the imaging findings of this uncommon clinical disorder and trail the blaze for future articles relating to this issue.     

Diagnostic and interventional procedures for the biliary tract

Various diagnostic imaging studies have been employed in the past year to evaluate the normal and abnormal biliary ductal system. Variations in the normal ductal drainage of the left lobe of the liver, in which the right lateral hepatic duct drained into the left hepatic duct, were studied because of the implications for the surgical resection of the left lobe. Choledochal cysts have been studied in adults using endoscopic retrograde cholangiopancreatography to evaluate the abnormal junction between the common bile duct and pancreatic duct and the long dilated common channel. An ultrasound study indicated that children with choledochal cysts also may have intrahepatic duct dilatation. An increased incidence of malignancy has been noted in adults with choledochal cysts, and their appearance on ultrasound, CT, and cholangiography were described. Cystic fibrosis produces abnormalities of the biliary tree, extrahepatic strictures, and more interestingly, intrahepatic ductal dilatation and abnormal contour without strictures. The usefulness of the preoperative ultrasonographic evaluation of the biliary tract in Oriental cholangiohepatitis was stressed. Bile duct abnormalities in fascioliasis were also noted on CT scans. Patterns of abnormality in the CT appearance of the thickened, contrast-enhanced, extrahepatic bile ducts were elucidated. Focal concentric, focal excentric, diffuse concentric, and diffuse excentric ducts were seen with various forms of pancreatic disease, choledocholithiasis, and various forms of cholangitis. An enhanced, thick-walled duct indicates disease, but is a nonspecific finding. Chronic cholecystitis was found to produce false-positive cholescintigram results in patients with suspected acute cholecystitis, but only in those with severe degrees of chronic cholecystitis. The results of multicenter trials using extracorporeal biliary lithotripsy in the United States have been published. They are somewhat disappointing and do not confirm the original excellent results reported in Germany for treatment of gallbladder stones. Much interest has been focused on the use of expandable metallic stents for the treatment of benign and malignant biliary obstruction. Preliminary data suggest good patency rates for benign lesions. Patency rates for malignant lesions are similar to those of previously available plastic stents.     

Monolobar Caroli’s disease with renal cysts: Case report

Caroli’s disease is autosomal recessive, non-obstructive dilatation of intrahepatic biliary ducts. The exact etiology is unclear. Two variants of Caroli’s disease are well known-simple; in which bile ducts are dilated without hepatic fibrosis and the second type which is associated with congenital hepatic fibrosis along with its sequelae, also known as Caroli’s syndrome. Simple Caroli’s disease without hepatic fibrosis is quite rare. The importance of recognizing this disease as a cause of biliary stasis is its frequent association with lithiasis, recurrent cholangitis, liver abscesses, cirrhosis and cholangiocarcinoma.     

Congenital bile duct dilatation (Caroli's disease--Grumbach's disease)

Congenital bile duct dilatation is an autosomal recessive inherited disease. Pathologically tortuous dilated, dysplastic intrahepatic bile ducts were found. It may be associated with hepatic fibrosis (Grumbach's disease), or without (Caroli's disease). A common additional finding is an infantile polycystic kidney. Three cases are reported and the radiological and sonographic findings are discussed.     

Hepatic arterial color doppler signals in Caroli's disease

Three siblings with congenital dilatation of the intrahepatic bile ducts (Caroli's disease) are presented. Bile duct pathology was associated with congenital hepatic fibrosis and polycystic renal disease in all three patients. On color Doppler imaging (CD imaging), multiple small color Doppler signals were observed in the vascular radicles within the dilated bile ducts or in the center of the lumen apart from the vascular radicles, as well as in other well-known sonographic findings such as bile duct dilatations and bilary calculi. Doppler frequency spectral analysis confirmed all these color signals as arterial in origin in all patients, revealing pulsatile wave patterns. In spite of the fact that portal venous radicles have been well described on conventional sonograms or computed tomography (CT), continuous wave patterns of venous flow on spectral analysis were not detected in all patients. Identification of such less emphasized arterial flow may add another clue in the diagnosis and pathogenesis of this rare disease entity. In conclusion, color Doppler signals of arterial wave pattern within the dilated bile ducts are another helpful diagnostic criteria in previously reported sonographic findings, and these color signals are easily depicted on sonograms with color mapping.     

Rare-MR-urography--a new diagnostic method in autosomal recessive polycystic kidney disease.

PURPOSE: To describe the appearance of autosomal recessive polycystic kidney disease (ARPKD) by using a new diagnostic method: RARE-MR-urography. MATERIAL AND METHODS: Eight children were evaluated using MR images from 0.23 T and 1.5 T MR units, using T1-weighted spin-echo and T2-weighted turbo spin-echo sequences and RARE-MR-urography. Signal intensities, morphological appearance of the affected kidneys and, specifically, the picture of the urinary tract in RARE-MR-urography, were evaluated. RESULTS: All children showed enlargement, reniform but humpy kidney shape, homogeneous-grainy renal parenchyma, normal renal pelvis and calyces. Although ARPKD is always associated with some degree of congenital hepatic fibrosis, there was no bile duct dilatation or liver fibrosis at the time of examination. Signal intensity was hyperintense in T2-weighted images in all cases. In 5 cases, T1-weighted images were hypointense. In RARE-MR-urography, hyperintense, linear, radial patterns in cortex and medulla were seen, which represent microcystic dilatation of collecting ducts and are therefore characteristic of ARPKD. Four patients presented with a few circumscribed small subcapsular cysts. CONCLUSION: RARE-MR-urography is a noninvasive method which demonstrates the pathognomonic water-filled cystic structures throughout the kindeys in ARPKD.     

MR imaging of the dilated biliary tract

The magnetic resonance (MR) examinations of 18 patients with dilated bile ducts were reviewed retrospectively to determine the capability of MR to demonstrate biliary dilatation, assess MR appearance of the dilated biliary tract using spin-echo techniques, and define the optimal MR imaging parameters (repetition time [TR] and echo time [TE]) for its demonstration. On images with short TR (0.5 sec) and TE (28 msec), the dilated intrahepatic and intrapancreatic bile ducts usually had lower signal intensity compared with the surrounding liver or pancreas; on images with long TR (2.0 sec) and TE (56 msec), they had higher signal intensity. Because of the observed variation in percentage of contrast between dilated bile ducts and surrounding liver and pancreas, two imaging sequences are recommended to obtain reliable demonstration of dilated intrahepatic and intrapancreatic bile ducts. The dilated common bile duct at the level of the hepatic hilus is best seen with a short TR and TE.     

The stilette sign: the appearance of dilated bile ducts in the fatty liver

The appearances of hepatic steatosis and of dilated intrahepatic bile ducts occurring independently are well described. When both conditions occur simultaneously a major sign of biliary obstruction, a double lumen with echogenic walls (the double-barrelled shotgun sign), is modified by the abnormally echogenic liver. The combined appearance is of a tubular structure with no echogenic interface with the liver, containing an echogenic structure at its centre representing echoes from the adjacent bile duct and portal vein walls. We have named this appearance the 'stilette' sign because of its resemblance to a fine needle within a tube. Its importance lies in the fact that it makes dilated intrahepatic bile ducts difficult to recognise by ultrasound.     

Gray scale ultrasonography in medullary cystic disease of the kidney and congenital hepatic fibrosis with tubular ectasia: new observations.

The gray scale ultrasound findings of three patients with medullary cystic disease of the kidney and two patients with congenital hepatic fibrosis with tubular ectasia are reported. Medullary cystic disease of the kidney typically presents early in adulthood with renal failure and salt-losing nephropathy. The spectrum of gray scale ultrasound findings in this entity includes irregular widened central echoes when small cysts are present and well defined cystic structures when larger medullary cysts are the predominant lesion. The ultrasound findings in congenital hepatic fibrosis with tubular ectasia seem to be a characteristic combination of nephromegaly, a distorted renal echo pattern, and high level echoes in the liver. Ultrasound is a useful noninvasive method which is complementary to other methods in the identification and differential diagnosis of bilateral renal cystic disease.     

Renal cystic disease in multisystem conditions

Five renal cystic diseases have significant extrarenal manifestations: autosomal dominant polycystic kidney disease (ADPCK), autosomal recessive polycystic kidney disease (ARDCK), tuberous sclerosis (TS), von Hippel-Lindau Syndrome (VHL), and medullary cystic disease (MCD). Knowledge of these extrarenal manifestations is important since they may precede, present simultaneously, or follow the onset of the renal cystic disease. This article discusses the most significant extrarenal manifestations of these five renal cystic diseases: (1) ADPCK: hepatic cysts and cardiovascular abnormalities; (2) ARDCK: portal hypertension; (3) TS: hamartoma-like tumors of other organs; (4) VHL: central nervous system hemangioblastomas and paragangliomas; and (5) MCD: congenital hepatic fibrosis. Detecting extrarenal manifestations may be helpful (1) in confirming the renal cystic disease; (2) in thoroughly evaluating the patient with known renal cystic disease, and (3) if they antedate the renal cystic disease, their presence will alert the radiologist to evaluate the kidneys.     

Renal cystic disease associated with orofaciodigital syndrome

Three families affected by the rare genetic disorder orofaciodigital syndrome, type I (OFD-1) were screened by computed tomography (CT) to determine the presence of cysts in the kidneys and liver, an association known to occur but not previously described in the radiologic literature. Renal cystic changes in four females with oral, facial, and digital malformations were variable and not distinguishable from other inherited cystic kidney diseases. One patient had biliary ectasia and hepatic cysts. “Polycystic” kidneys occurring only in female members of a family should suggest OFD-1, an X-linked dominant disorder that is lethal in utero in males. Patients known to have the syndrome should be screened for cystic renal disease.     

The portal venous tree simulating dilated biliary ducts on computed tomography of the liver

Intrahepatic portal veins may be identified on routine computed tomography (CT) of the liver. These venous structures appear as linear and branching, low-density regions in the liver which appear to converge at the porta hepatis. Intrahepatic portal veins may simulate the appearance of dilated intrahepatic bile ducts. Venous structures may be distinguished from dilated bile ducts by their obliteration following intravenous infusion of urographic contrast agents. CT numbers of portal veins tend to be somewhat higher than those of dilated bile ducts, but enough overlap of values exists to make reliance upon these numbers in an individual case suspect.     

Sonographic differentiation of enlarged hepatic arteries from dilated intrahepatic bile ducts

Identifying parallel tubular structures within the liver by sonography has been regarded as a sensitive and specific sign of intrahepatic duct dilatation. Eight cases are reported in which parallel tubes within the liver were shown not to represent dilated ducts on computed tomography, but rather enlarged hepatic arteries due to increased blood flow. All eight patients had a history of alcoholism and/or cirrhosis and had at least one ancillary sign of portal hypertension. The sonographic findings in these eight patients were compared with similar findings in 12 other patients who were subsequently found to have true intrahepatic bile duct dilatation. Sonographic features that were helpful in distinguishing these two groups are described.     

MR cholangiography in children and young adults with biliary disease

OBJECTIVE: Our objective was to describe the MR cholangiography findings for young patients with suspected biliary disease who underwent half-Fourier acquisition fast spin-echo technique with respiratory triggering. SUBJECTS AND METHODS: Twenty-eight MR cholangiography studies were performed in 22 patients on a 1.5-T MR unit. Ten of these 22 patients had undergone liver transplantation. RESULTS: MR cholangiography revealed abnormalities of both the extrahepatic and the intrahepatic major and minor bile duct systems, despite the small diameter of the duct system in this group of patients. Four patterns of biliary disease were shown: global dilatation of extrahepatic or intrahepatic ducts (n = 7); segmental, uniform dilatation of central or peripheral intrahepatic ducts (n = 9); segmental, nonuniform dilatation of central or peripheral intrahepatic ducts (n = 2); and fusiform ectasia with segmental, irregular intrahepatic dilatation and bile lakes (n = 2). The findings of eight studies were interpreted as normal. The four patterns of abnormalities were correlated with the results from percutaneous transhepatic cholangiography, T-tube cholangiography, and liver biopsy and with clinical and surgical information, as available. CONCLUSION: MR cholangiography is a noninvasive technique for evaluation of biliary disease. The improved resolution afforded by respiratory triggering permits evaluation of both major and minor bile ducts, even in young, uncooperative subjects. Four patterns of abnormalities were prospectively identified, correlated with other information, and used to direct clinical treatment.