efecto de la edad en el conducto hepatico comun

8/11/2019 Efecto de La Edad en El Conducto Hepatico Comun

1/4

Effect of Aging on the AdultExtrahepatic Bile Duct

A Sonographic Study

Gil N. Bachar, MD, Maya Cohen, MD,Alexander Belenky, MD, PhD, Eli Atar, MD,Shafir Gideon, MD

Objective. To determine whether the size of the extrahepatic bile duct increases with age in adults.

Methods. We prospectively collected data on 251 patients aged 20 years or older who underwent

abdominal sonography. None of the patients had a history of liver, gallbladder, biliary, or pancreatic

disease or surgery. The extrahepatic bile duct was measured at 3 locations: in the porta hepatis, in the

most distal aspect of the head of the pancreas, and midway between these points. Least squares lin-

ear regression was used to correlate patient age and the size of the extrahepatic bile duct. Results.

There were 126 men and 125 women aged 20 to 94 years (mean SD, 52.5 17.63 years). Twelve

percent of the study population were younger than 30 years, and 12% were older than 80 years. The

mean diameters of the common bile duct in the 3 locations were as follows: proximal, 3.39 1.14 mm;

middle, 3.72 1.28 mm; and distal, 4.28 1.18 mm. The overall mean for all measures was 3.66

1.15 mm. The width of the common bile duct ranged from 1.0 to 8.6 mm. There was a significant

correlation between common bile duct size and age (r= 0.535; P< .001). Mean common bile duct

sizes were 3.128 0.862 mm in the patients younger than 50 years and 4.19 1.15 mm in the

patients older than 50 years (P< .001 by independent t test for equality of means). We have foundthat the duct gradually dilated 0.04 mm/y. Conclusions. This study revealed an age-dependent change

in the diameter of the extrahepatic bile duct. We suggest that the upper normal limit of the duct in

elderly persons be set at 8.5 mm. Key words: aging; bile ducts; sonography.

Received May 27, 2003, from the Department ofRadiology, Rabin Medical Center, Petah Tiqva,Israel; affiliated with the Sackler Faculty ofMedicine, Tel Aviv University, Tel Aviv, Israel.Manuscript accepted for publication June 5, 2003.

Presented at the 88th Scientific Assembly of theRadiological Society of North America, Chicago,Illinois USA, December 16, 2002.

Address correspondence and reprint requests toGil N. Bachar, MD, Department of Radiology, RabinMedical Center, Beilinson Campus, Petah Tiqva49100, Israel.

E-mail: [email protected].

AbbreviationsCBD, common bile duct

onography is a well-established method for evalua-tion of the extrahepatic biliary system and serves asa major tool in the diagnosis of suspected bile ductobstruction. The generally accepted normal size

range for the extrahepatic bile duct at the level of thecommon bile duct (CBD) in the porta hepatis is 2 to7 mm.13 However, a few researchers have found that theCBD diameter undergoes age-dependent variations.25 In1984, Wu et al4 reported that the diameter of the CBDincreases normally by 1 mm every decade. Thereafter,other sonographic studies established 4 mm as the nor-mal mean CBD diameter at age 40 years, 5 mm at 50years, and 8 mm at 80 years.2,3,5 These findings wererecently challenged by Horrow and associates,6 whoobserved no increase in CBD size with age. The aim ofthis study was to determine whether the size of the extra-hepatic bile duct increases with age in adults.

2003 by the American Institute of Ultrasound in Medicine J Ultrasound Med 22:879882, 2003 0278-4297/03/$3.50

S

Article


2/4

Materials and Methods

Patient DataBetween November 2001 and March 2002, we

prospectively collected data on 251 patients aged20 years or older who underwent abdominalsonography at our unit by 1 of 2 experienced radi-ologists (G.N.B. and S.G.). None of the patients hada history of liver, gallbladder, biliary, or pancreaticdisease or surgery. Patients with cholelithiasis orany gallbladder or pancreatic abnormality wereexcluded. In all cases, levels of serum bilirubin,alkaline phosphatase, and liver transaminaseswere measured before the examination and werewithin reference ranges. Patients who were takingmedication that causes relaxation of smooth mus-cle (e.g., calcium blockers and papaverine

hydrochloride) were excluded from the study.The sonographic scan was performed after a

fasting state of 6 to 12 hours with an HDI 3000device (Philips Medical Systems, Bothell, WA)equipped with a 2- to 4-MHz broadband convexarray transducer. The patients were examinedduring deep inspiration in the supine or left later-al oblique position by a right subcostal approach.The extrahepatic bile duct was identified at thelevel of the portal vein, where the hepatic arterycrosses perpendicularly between them. Whenbowel gas obscured a part of the suprapancreatic

segment, we had the patient take several deepbreaths and hold the inspiratory phase. ColorDoppler sonography was used to confirm theidentification of the vascular and ductal anatomy.The extrahepatic bile duct was measured at 3 loca-tions: in the porta hepatis, in the most distalaspect of the head of the pancreas, and midwaybetween these points. For each location, antero-posterior measurements from inner border toinner border were obtained from the longitudinalimages using electronic calipers. Three measure-ments were taken in the 3 locations for eachpatient, and the mean values were calculated.

Statistical AnalysisValues are expressed as mean SD. Least squareslinear regression was used to correlate patient ageand size of the extrahepatic bile duct. The mean ofthe 3 measured diameters was used as the depen-dent variable, and age was used as the indepen-dent variable. The independent ttest and one-wayanalysis of variance were used to compare themean values between age groups. Type I error =0.05 and P< .05 were considered significant.

Results

There were 126 men and 125 women aged 20 to94 years (mean SD, 52.5 17.63 years). Twelve

percent of the study population were youngerthan 30 years, and 12% were older than 80 years(Fig. 1). The mean diameters of the CBD in the 3locations were as follows: proximal, 3.39 1.14mm; middle, 3.72 1.28 mm; and distal, 4.28 1.18 mm. The overall mean for all measures was3.66 1.15 mm. The width of the CBD rangedfrom 1.0 to 8.6 mm. None of the patients hadwidening of the intrahepatic bile ducts. Therewas a significant correlation between CBD sizeand age (r= 0.535; P< .001; Fig. 2; r2 = 0.28, whichmeans that 28% of the variation of CBD can beexplained by age). The mean CBD sizes were 3.13

0.862 mm in the patients younger than 50 yearsand 4.19 1.15 mm in the patients older than50 years (P< .001 by independent ttest for equal-ity of means). Table 1 lists the means, SDs, andranges of the duct dimensions in the 7 agegroups. We have found that the duct graduallydilated 0.04 mm/y.

Discussion

A study by Wu et al4 in 1984 established the effectof age on the size of the extrahepatic bile duct.

The study consisted of 256 patients without bil-iary, pancreatic, or hepatic disease. However,there were 18 subjects younger than 21 years,only 10 subjects older than 70 years, and noneolder than 90 years. The sizes of the extrahepaticbile ducts ranged from 1 to 10 mm and were agedependent (r = 0.60; P < .001). By contrast,Horrow et al,6 in a prospective study of 258patients, failed to observe any increase in CBD

880 J Ultrasound Med 22:879882, 2003

Aging and Common Bile Duct

Figure 1. Patients in the 7 age groups.


3/4

size with age. They measured maximal antero-posterior and transverse diameters of the extra-hepatic bile duct in the same 3 locations usedhere. The overall mean for all measures was 3.5 1.2 mm, with a range of 1.7 to 6.0 mm. The leastsquares regression slope was 0.000578 0.000334 mm/y, which differs significantly fromthe null hypothesis of 0.1 mm/y (P < .001)described by Wu et al.4 However, the study byHorrow et al6 had several major limitations. First,about half the subjects were 45 to 60 years of age,and age was not uniformly distributed across thesamples, so that too little weight may have beenaccorded the very young and the very old. It ispossible that the inclusion of larger numbers ofyounger and older patients would have yielded astatistically significant correlation between age

and size of the bile duct. Moreover, in these otherstudies and also in ours, all measurements weredone by only 1 or 2 observers, whereas Horrow etal6 used 3 radiologists and 6 sonographers, lead-ing to a possible interobserver bias. Third, thepatients included in the study were only askedabout previous biliary or pancreatic disease, butlaboratory parameters, such as serum bilirubin,alkaline phosphatase, and liver transaminaselevels, were not measured before the examina-tion. Thus, some of the patients might have hadcholelithiasis or choledocholithiasis. In our

study, as in that of Kaim et al,5

laboratory param-eters were measured at most 3 days before sono-graphic imaging.We found a significant correlation between

CBD size and age (r= 0.535; P < .001; r2 = 0.28,which means that 28% of the variation of CBDcan be explained by age). These results are veryclose to the results of Wu et al.4We found a sig-nificant difference between the groups youngerthan 50 and older than 51 years: 3.13 0.86 ver-sus 4.19 1.15 mm (P< .001). Moreover, accord-ing to the mean diameter of the duct in everydecade (Fig. 2), we found that the duct graduallydilated 0.04 mm/y.

These results are consistent with those from astudy by Kaude7 in 350 healthy subjects aged 20to 71 years; they reported CBD size from 2.8 to4.1 mm. Kaim et al5 studied an elderly sample of45 patients older than 75 years; the mean CBDdiameter was 6.2 2.3 mm, with a range of 2.1 to15.0 mm, which was considerably wider then therecommended borderline values in the ultra-sound literature. Perret et al3 evaluated the CBDdiameter in 1018 healthy subjects aged 60 to 96

years and again found a small albeit statisticallysignificant increase from 60 years and younger(3.6 0.2 mm) to 85 years and older (4.0 0.2mm) (P < .009). In a retrospective study usingstepwise discriminate analysis of cholangio-grams obtained by endoscopic retrogradecholangiopancreatography in 165 subjects,Barthet et al8 noted a significant correlation ofbiliary duct diameter with age (r= 0.27; P= .001).

The enlargement of the bile ducts in elderlysubjects may be explained by the characteristicfragmentation of the longitudinal smooth myo-cyte bands and interspersed connective tissuecombined with the decrease in the reticular-elas-tic framework of the duct wall over time,9whichleads to reduced contractility and hypotonus ofthe CBD. Moreover, drugs such as calcium antag-onists and nitroglycerine, which are frequentlytaken by the elderly population, may influence

J Ultrasound Med 22:879882, 2003 881

Bachar et al

Figure 2. Average CBD diameter versus age (n = 251).

Table 1. Means, SDs, and Ranges of CBD Diameterin the 7 Age Groups

CBD Diameter, mmAge, y Mean SD Range

2030 2.735 0.735 1.24.93140 3.033 0.808 1.54.84150 3.476 0.834 2.15.35160 3.648 0.838 2.16.86170 4.069 1.092 2.18.37180 4.265 1.008 2.16.581 5.033 1.103 3.97.1

P < .0001.


4/4

the contractility and tonus of the duct wall. Thesedifferences may explain the considerable varia-tions reported for the upper limit of the normalCBD diameter, namely 4, 6, and 7 mm.2,46,10,11

These inconsistent findings may have been dueto the different inclusion criteria and patientselection in these studies. Moreover, measure-ments in the early reports5,7were taken in differ-ent locations along the CBD. We measured thebile duct at the same locations used by Horrow etal6 and Wu et al4: the porta hepatis, the most dis-tal aspect of the head of the pancreas, and mid-way between the two. For each location,anteroposterior measurements were obtainedfrom the longitudinal images and were madefrom inner border to inner border with electroniccalipers. Our study shows that the width of the

CBD differs greatly among the 3 locations, withmean SD values of 3.39 1.14 mm proximally,3.72 1.28 mm at the middle, and 4.28 1.18 mmdistally. Thus, the CBD gradually widens from theporta hepatis to the head of the pancreas.Moreover, in the 10 subjects aged 48 to 85 years,ectasia was noted in the middle of the duct, andthere was a difference of up to 4.2 mm betweenthe thinnest and widest parts of the duct withinthe same patient. Thus, it is difficult to set a nor-mal upper limit for the elderly population.Although Wu et al4 suggested that the normal

upper limit for the elderly should be set at 10 mm,only a relatively small number of their patients(29 of 258) were older than 60 years. Kaim et al,5

who limited their sample to patients older than 75years, reported a mean width of 6.5 2.5 mm anda range of 2.1 to 15.0 mm, both values consider-ably higher than reported by others.26

Parulekar11 studied 73 patients between theages of 20 and 65 years who were fasting and hadno evidence of biliary or pancreatic disease. Theupper limit of the CBD was 7.0 mm, and themean was 4.1 mm. Bowie2 suggested that theupper limit of the normal CBD should be consid-ered 7 mm. Our results confirm that there is aconsiderable increase in the CBD diameter inelderly subjects in comparison with youngerpopulations. However, our group included 2patients aged 85 and 86 years with a CBD diame-ter of 8.5 mm and 1 patient aged 66 years with adiameter of 8.6 mm and no enlargement of theintrahepatic bile ducts, no evidence of cholelithi-asis, and normal laboratory parameters. We sug-gest that 8.5 mm be considered the upper limit ofthe normal CBD in elderly patients.

In conclusion, this study showed an age-dependent change in the diameter of the extra-hepatic bile duct. We suggest that the uppernormal limit of the duct in the elderly should beset at 8.5 mm.

References

1. Laing FC. The gallbladder and bile ducts. In: Rumack

C, Wilson S, Charboneau JW, eds. Diagnostic

Ultrasound. St Louis, MO: CV Mosby Co; 1998:

175216.

2. Bowie JD. What is the upper limit of normal for the

common bile duct on ultrasound: how much do you

want it to be? Am J Gastroenterol 2000; 95:897

900.

3. Perret RS, Sloop GD, Borne JA. Common bile ductmeasurements in an elderly population. J Ultrasound

Med 2000; 19:727730.

4. Wu CC, Ho YH, Chen CY. Effect of aging on com-

mon bile duct diameter: a real-time ultrasonograph-

ic study. J Clin Ultrasound 1984; 12:473478.

5. Kaim A, Steinke K, Frank M, et al. Diameter of the

common bile duct in the elderly patient: measure-

ment by ultrasound. Eur Radiol 1998; 8:14131415.

6. Horrow MM, Horrow JC, Niakosari A, Kirby CL,

Rosenberg HK. Is age associated with size of the

adult extrahepatic bile duct: sonographic study.

Radiology 2001; 221:411414.

7. Kaude JV. The width of the common bile duct in

relation to age and stone disease: an ultrasono-

graphic study. Eur J Radiol 1983; 3:115117.

8. Barthet M, Spinoza S, Affriat C, Berthzene P, Sahel J.

Influence of age and biliary lithiasis on the diameter

of the common bile duct [in French]. Gastroenterol

Clin Biol 1995; 19:156160.

9. Kialian GP, Aznaurian AV. The aged related charac-

teristics of the muscular layer of the common bile

duct in man [in Russian]. Morfologiia 1995;

108:1012.

10. Majeed AW, Ross B, Johnson AG, Reed MWR.

Common duct diameter as an independent predic-

tor of choledocholithiasis: is it useful? Clin Radiol

1999; 54:170172.

11. Parulekar SG. Ultrasound evaluation of common bile

duct size. Radiology 1979; 133:703707.

882 J Ultrasound Med 22:879882, 2003

Aging and Common Bile Duct

efecto de la edad en el conducto hepatico comun

Documents