Indian Journal of Radiology Indian Journal of Radiology  

   Login   | Users online: 455

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size     

 

DR. N.G. GADEKAR MEMORIAL ORATION Table of Contents   
Year : 2002  |  Volume : 12  |  Issue : 1  |  Page : 109-114
55th Conference of IRIA, Kolkata, 2002


India

Click here for correspondence address and email
 

How to cite this article:
Rahalkar M D. 55th Conference of IRIA, Kolkata, 2002. Indian J Radiol Imaging 2002;12:109-14

How to cite this URL:
Rahalkar M D. 55th Conference of IRIA, Kolkata, 2002. Indian J Radiol Imaging [serial online] 2002 [cited 2019 Nov 18];12:109-14. Available from: http://www.ijri.org/text.asp?2002/12/1/109/30552
Serendipitous Detection of IVC Anomalies

Incidental visualization of the developmental anomalies of the venous system in the retro-peritoneum on abdominal CT scan has increased our awareness of them, which would otherwise go un-detected. The recognition of their appearances are of paramount importance, lest they may be misinterpreted as pathologic. The complicated embryogenesis of the IVC provides numerous opportunities for developmental errors. Most of these anomalies are easy to recognize, if their embryology is well understood, each section painstakingly reviewed and the IVC or its anomalous courses are followed through sequential slices.

The earliest reference to this subject is in 1793, when Abernethy described a case of congenital mesocaval shunt with Azygos continuation of IVC in a 10 month old infant with dextrocardia and polysplenia[1].

Embryogenesis of IVC

The IVC and its tributaries are formed by a complicated process, between 6 and 8 weeks of intra-uterine life, involving development, anastomosis, and regression of 3 pairs of embryonic venous channels, returning blood from the trunk and lower extremities. They are, in order of appearance, the posterior cardinals (labelled as No. 1), the subcardinals (labeled as No. 2), antero-medial to posterior cardinals and antero-lateral to aorta) and supracardinals (labeled as No. 3, also called as lateral sympathetic line veins and lying postero-medial to posterior cardinals & postero-lateral to aorta) [Figure - 1][Figure - 2] Supracardinals separate into one more channel on both sides, which develop Azygos/Hemiazygos veins cranially and lumbar veins caudally.

Multiple anastomoses take place between subcardinals (anterior as well as posterior to aorta), which form the renal vein collar, giving rise to renal veins either pre or retro-aortic. Anastomoses also develop between sub and supra-cardinals and also between posterior cardinals and supracardinals.

Through progressive asymmetry, right-sided dominance, enlargement or regression of some channels, emerges the final course of the IVC. [Figure - 3]. It is formed by:

A)Post-renal segment - small portion of right posterior cardinal and caudal portion of right supracardinal veins (No. 1 and 3, in [Figure - 3])

B) Renal segment - Renal collar involving right supra-subcardinal and intersubcardinal anastomoses (No. 2 in [Figure - 3]).

C) Pre-renal segment - middle part of right subcardinal

D)Hepatic segment - anastomosis between right subcardinal and hepato-cardiac channel, separately derived from right vitelline vein.

Classification of IVC anomalies

Siegfried[2] had described the classification of IVC anomalies in 1983. Subsequently relatively very few articles have been published on this subject. I would like to present a slightly modified classification, which is as follows:

I) Situs inversus: Left IVC

II) Situs solitus:

A) Infra-renal Segment

a) Transposition of IVC (left sided IVC)

b) Duplication of IVC

1) with normal supra-renal cava

2) with absent supra-renal cava & Azygos/hemiazygos continuation[3].

c) Retro-caval ureter with persistent right posterior cardinal vein.

d) Duplication of right IVC due to persistent right posterior cardinal as well as supra-cardianl veins.

e) Absence of infra-renal or entire IVC is rare, though described in the literature[4].

B) Renal Segment -

a) Retro-aortic left renal vein

b) Circum-aortic left renal vein

C) Supra-renal segment

a) Hepatic interruption of IVC with

1) right or left IVC

2) Azygos or Hemiazygos continuation

3) varying courses of left & right renal vein

4)may be associated with dextro cardia,polysplenia/asplenia syndrome

b) Congenital web or diaphragm at the junction of IVC with right atrium.

Case Material

A careful scrutiny was made to follow the course of the IVC to detect any anomaly in all examinations of abdomen. A few anomalies were picked up even on CT of lumbar spine, which were followed-up with contrast studies. A few cavograms were obtained to please and convince the clinicians. All cases of IVC anomalies were detected serendipitously, i.e. by a pleasant chance during the examinations for un-related clinical indications. In one case of congenital web of IVC, only some form of caval obstruction was suspected due to oedema and collateral veins over the trunk and lower extremities.

A) Infra-renal Segment anomalies

1) Trans-Position of IVC (Left IVC)

Incidence - 0.2 - 0.5%

Right supra-cardinal vein regresses, left supra cardinal vein persists. A single IVC ascends to the left of the spine crosses anterior and/or posterior to the aorta at the level of renal hilum, and then ascends towards right atrium.

Less commonly - Lt. IVC Hemiazygos continuation Azygos vein or persistent left SVC/coronary sinus or left brachio-cephalic vein or superior intercostal vein.

2) Duplication of IVC

Incidence - 0.2 - 3.0%; the supra-cardinals persist normal IVC and left IVC crossing to right at the level of renal veins [Figure 4],[Figure - 5] and [Figure - 6].

Less commonly it may be associated with hepatic interruption of IVC with Azygos or Hemiazygos continuation and varying courses of left and right renal veins, or Polysplenia syndrome, which consists of dextro-cardia, polysplenia/asplenia, ambiguous situs, bilateral left-sidedness, short pancreas, mal-rotation of gut & common coelico-mesentric trunk, as reported by Dwivedi et al [5].

3) Circum-Caval (Retro-Caval) Ureter:

This is an anomaly of development of IVC and not the right ureter. Normally ureter develops as a bud from Wolffian duct that grows towards the developing metanephros through the aperture between right posterior cardinal and right supra-cardial veins [Figure - 7]. When right supra-cardinal vein fails to develops and right posterior cardinal vein forms IVC, the earlier course of ureter persists. Thus the future right ureter courses posterior, then medial and finally anterior to cava and right iliac vessels, thus partially circumscribing the cava.

The patients present in adulthood with obstructive hydronephrosis. The dilated ureter shows an obstruction usually at the level of L3. where it takes a medial turn with an 's' shaped deformity.

4) Duplication of Normal Right IVC

Rarely both right supracardinal as well as posterior cardinal vein segments may persist, producing duplication of right infra-renal cava and the right ureter coursing between the two cavae [Figure - 8],[Figure - 9] and [Figure - 10], hitherto not described in the literature.

B) Renal Vein Segment Anomalies

These are mainly concerning course of the left renal vein (other than the pre-aortic, which is normal) such as:

a) Retro-aortic LRV - 2-3%, the dorsal limb of renal venous collar persists. Usually retro-aortic LRV descends a few vertebral levels, before crossing to unite the cava.

b) Circum-aortic LRV - 6-8.7%, both limbs of venous collar persist.

C) Supra-renal Segment Anomalies

1) Absence of hepatic segment with Azygos continuation of IVC

Incidence 0.6%. This anomaly develops from failure to form right subcardinal-hepatic anastomosis [Figure - 11]. Blood is shunted from right supra and sub-cardinal anastomosis retro-crural Azygos vein dilated Azygos vein on Chest X-ray [Figure - 12],[Figure - 13],[Figure - 14],[Figure - 15],[Figure - 16],[Figure - 17]

2) Congenital Web/Diaphragm of IVC

There may be a web or a diaphragm in IVC at its

junction with right atrium due to atresia of right vitelline vein. The patient may present in adulthood with slowly developing obstruction of IVC with formation of collaterals and pedal oedema. Contrast venography [Figure - 18], ultrasound and interventional technique to dilate the stenosis have an important role to play in the management.

Significance & Relevance of IVC Anomalies

A) To Radiologists:

a) Not to mistake anomalous veins for lymph nodes (retro-crural particularly), dilated ureters, gonadal veins, supra-renal or para-spinal mass.

b) Diagnostic challenge, e.g. Left Hemiazygos vein lying closely posterior to aorta may look like dissection of aorta.

c) Investigation of IVC obstruction due to any anomaly.

B) To cardiologists and surgeons:

1. Cardiologists are only worried about the entry of a venous catheter from a femoral vein into the right atrium, irrespective of its course. Hence the only anomaly that bothers them is hepatic interruption of IVC with Azygos continuation. According to one series, 0.2 to 4.3% of cardiac catheterizations for congenital heart diseases reveal an IVC anomaly.

2. Ligation of an anomalous vein may lead to some clinical problems in cases of porto-caval shunts, kidney donation, nephrectomy or repair of abdominal aortic aneurysm. Brener[6] reported that 40% of retro-aortic renal veins were injured in a large group of patients undergoing surgery for abdominal aortic aneurysm.

C) To Vascular & Interventional Radiologists:

a) Placement of IVC filters & continued pulmonary embolisation in spite of IVC filter due to un-suspected double IVC

b) Renal vein sampling

Conclusion

The development of IVC is complex and subject to a range of variations & anomalies. Yet it is difficult for anybody to come across as many as have been described. Hence the purpose of this oration is to present a spectrum of images rather than statistics of numbers. The subject once again proves how, we, the imageologists can see the internal anatomy better than the operating surgeons and dissecting anatomists.

Acknowledgments

I am grateful to Dr. Jagdish Modhe, HOD, Radiology Department, Hinduja Hospital, Mumbai, for allowing me to include cases of interruption of IVC.

 
   References Top

1.Bass JE, Redwine MD, Kramer LA et al. Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings. Radiographics 2000; 20L 634-652.  Back to cited text no. 1    
2.Siegfried MS, Rochester D, Bernstein JR et al. Diagnosis of inferior vena cava anomalies by computerized tomography. Comput Radiol 1983; 7: 119-123.  Back to cited text no. 2    
3.Cohen MI, Gore PM, Vogelzag RL et al. Accessory hemiazygos continuation of left inferior vena cava: CT demonstration. J Comput Assist Tomography; 8: 777-779.  Back to cited text no. 3    
4.Bass JE, Redwine MD, Kramer LA, Harris JH Jr. Absence of infra-renal inferior vena cava with preservation of the supra-renal segment as revealed by CT and MR venography. Am J Roentgenol 1999; 172: 1610-1612.  Back to cited text no. 4  [PUBMED]  
5.Dwivedi MK, Dewangan L , Kaur G. Radiological Quiz - Abdomen. Ind J radiol 2001; 11-1: 39-40.  Back to cited text no. 5    
6.Brener BJ et al. Major venous anomalies complicating abdominal aortic surgery. Arch Surg 1974; 108: 159-165.  Back to cited text no. 6    

Top
Correspondence Address:
M D Rahalkar
India

Login to access the Email id

Source of Support: None, Conflict of Interest: None


Rights and PermissionsRights and Permissions


    Figures

[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9], [Figure - 10], [Figure - 11], [Figure - 12], [Figure - 13], [Figure - 14], [Figure - 15], [Figure - 16], [Figure - 17], [Figure - 18]

This article has been cited by
1 Origin of the infrarenal part of the caudal vena cava in the pig
Cornillie, P., Van Den Broeck, W., Simoens, P.
Journal of Veterinary Medicine Series C: Anatomia Histologia Embryologia. 2008; 37(5): 387-393
[Pubmed]
2 Prenatal development of the caudal vena cava in mammals: Review of the different theories with special reference to the dog
Cornillie, P., Simoens, P.
Journal of Veterinary Medicine Series C: Anatomia Histologia Embryologia. 2005; 34(6): 364-372
[Pubmed]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Email Alert *
    Add to My List *
* Registration required (free)  


    References
    Article Figures

 Article Access Statistics
    Viewed3584    
    Printed91    
    Emailed1    
    PDF Downloaded0    
    Comments [Add]    
    Cited by others 2    

Recommend this journal