148
CLINICAL RADIOLOGY
9 Caro J J, Trindade E, McGregor M. The risks of death and severe non-fatal reactions with high versus low osmolality contrast media; A meta-analysis. American Journal of Radiology 1991; t 56:825-832. 10 K a t a y a m a H, Yamaguchi K, Kozuka T, Takashima T, Seez P, Matsuura Ki A report from the Japanese Committee on the safety of contrast media. Radiology 1990;175:621 628.
SiR 1 wish to thank Professor Grainger for his comments on 'Deep venous thrombosis following iopamidol venography'. He has considerably broadened the discussion to make several observations regarding the selection of contrast media for venography which are of interest. l would like to respond to some of the points raised: 1 Low Osmolar Contrast Media (LOCM) have clearly been shown to have superior clinical tolerance to High Osmolar Contrast Media (HOCM) [1] and to produce less phlebographic venous thrombosis [2] and it is the extreme rarity of clinically significant thrombosis with L O C M which makes this case interesting. 2 Diagnostic images can be obtained in most cases with diluted contrast media, but the need to dilute contrast has not been clearly established. Iopamidol 300 is specifically recommended by the manufacturer for venography (Merck Data Sheet), and is, I suspect, commonly used in clinical practice. A very recent radiological text [3] recommends that for venography 'If ionic agents have to be used then it is advisable that they be diluted to bring their osmolality closer to that of plasma'. I presume that this refers to H O C M and implies that non-ionic agents do not have to be diluted, although the same chapter does recommend slight dilution for lower limb venography '60 to I00 ml of contrast media (preferably a low osmolar or non-ionic medium; approx. 250 m g l/ml)'. 3 Professor Grainger's statement that admixture of blood and contrast in the syringe 'may well have occurred and caused the massive phlebothrombosis' is unjustifiable since, as stated in the article, 'It is our policy to flush the injection system with normal saline before and after contrast administration, and not to allow the mixing of blood and contrast in the syringe during angiography'. 4 Low osmolality and non-ionicity are not synonymous and I do not equate them. The discussion must be read in context and is specifically related to a complication of a non-ionic contrast iopamidol. Nonionic contrast media do have low osmolality. The concern about the tendency of blood to coagulate in the presence of contrast refers to non-ionic contrast media and not all LOCM. The decreased complications with iopamidol noted by Lea T h o m a s et al. [2] are related to conventional high osmolar ionic contrast media commonly used at that time for venography and do not, of course, apply to ioxaglate.
that shown in Fig. 4 of the article by McNicholas and associates, Our series of orbital pseudotumours increased to 43 by 1988, when this problem was extensively described [3]. There did appear to be a slight clinical difference, particularly regarding outcome, between the anterior and the diffuse group. l wonder whether Dr McNicholas and associates would note any clinical or outcome difference in their diffuse category if they were to divide them based on those patients who appear to have more specific anterior involvement. R. A. N U G E N T
Vancouver General Hospital British Columbia's Health Sciences Centre Vancouver B.C. V5Z IM9 Canada
References
I McNicholas M M J , Power W J, Griffin JF. Idiopathic inflammatory pseudotumour of the orbit: C T features correlated with clinical outcome. Clinical Radiology 1991;44:3 7. 2 Nugent RA, R o o t m a n J, Robertson WD, Lapointe JS, Harrison PB. Acute orbital pseudotumours: classification and CT features. American Journal of Neuroradiology 1981;2:431 436. 3 R o o t m a n J. Diseases of the orbit. Philadelphia: J.B. Lippincott Company, 1988:159 175.
SiR - We thank Dr Nugent for his interest in our article. We note the extra category of anterior pseudotumour which he described in his article [1]. The only case in our series which resembled this category was Case 13 which is shown in Fig. 4. This patient however had evidence of myositis and an inflammatory mass on a subsequent scan and we included him in our diffuse category. All five patients in this category were difficult to manage. All had recurrent disease and required second line treatment. The case in question required immunosuppression and irradiation and still requires treatment with steroids. Perhaps with a larger series it might be possible to demonstrate a difference in response between patients with diffuse disease and patients with disease affecting only the posterior scleral margin and adjacent optic nerve. In our series we had no patient who fitted exactly into this category and so we cannot c o m m e n t on differences in clinical outcome which might be evident between groups. M. M. J. M c N I C H O L A S
I am confident that the readers of this Journal are well aware of the difference between non-ionicity and low osmolality and will not be 'seriously mislead' by my discussion. L. H. COPE
South Tyneside Distriet Hospital Harton Lane South Shields Tyne and Wear NE34 OPL
Department of Diagnostic Imaging St Vincent's Hospital Elm Park Dublin 4
.Reference
1 Nugent RA, R o o t m a n J, Robertson WD, Lapointc JS, Harrison PB. Acute orbital pseudotumours: classification and CT features. American Journal o)c Roentgenology 1981;137:957-962.
References
1 Grainger RG, Dawson P. Low osmolar contrast media: an appraisal. Clinical Radiology 1990;42:1 5. 2 Lea T h o m a s M, Kealing FP, Piaggio RB, Treweeke PS. Contrast agent induced thrombophlebitis following leg phlebography: Iopamidol versus meglumine iothalamate. British Journal of Radiology 1984;57:205 207. 3 Grainger RG, Allison D J, eds. Diagnostic Radiology. Churchill Livingstone, 1992:2278 2299.
INFLAMMATORY
PSEUDOTUMOUR
OF ORBIT
S l ~ - 1 read with interest the article by M. J. J. McNicholas and associates entitled 'Idiopathic inflammatory pseudotumour of the orbit: CT features correlated with clinical outcome' [I]. The authors categorize these patients into four CT groups. In 1981, we categorized sixteen patients into five groups [2]. Four of these were the same as those used by the above authors, with the fifth category being the anterior group. The anterior pseudotumours involve the posterior scleral margin, usually with posterior extension along the adjacent optic nerve. The appearance, in fact, is somewhat similar to
DEFLATING
AN ANGIOPLASTY
BALLOON
SIR - We wish to report a complication of percutaneous transluminal angioplasty and its management. A 70-year-old w o m a n with 50 yard claudication and a right c o m m o n iliac stenosis (70% diam.) underwent right c o m m o n iliac angioplasty. The right c o m m o n femoral artery was punctured and the lesion crossed with a 0.035 in diam. straight guide wire. A 6 French (F) sheath was inserted and a 5F 4cm 8ram diam. balloon catheter (AXM5/35/80/8/4, William Cook) was passed through this and across the stenosis. The 0.035 in wire was replaced with one of 0.025 in diameter through a Tuohy Borst Y connector to allow catheter flushing and manometry. A trans 'stenotic' gradient of 25 m m H g was measured between the catheter tip and the sheath side arm. The balloon was inflated with an equal parts mixture of Ioxaglate 320 and normal saline at 7 atm pressure for 1 rain, during which the 'waist' effect of the stenosis was abolished. Following this single inflation the balloon could not be deflated despite full negative pressure with a 50ml syringe. Despite the failure of deflation, gentle traction on the catheter shaft moved the balloon (still under negative pressure) without apparent resistance. The 10 cm sheath was therefore advanced as far as possible and the balloon slowly withdrawn, still under negative pressure, until it obstructed the sheath orifice.
149
CORRESPONDENCE Catheter tip pressure recording during this showed no gradient across the angioplasty site and a digital subtraction arteriogram (contrast injected through the balloon catheter tip) showed no residual stenosis or apparent damage along the track of the balloon withdrawal. The course of the external iliac artery c o m m o n femoral artery was relatively straight and therefore, with balloon and sheath held together by gentle pull and push respectively, the stilette of a 22 gauge Chiba needle was passed through the sheath parallel to the balloon catheter shaft to puncture the balloon at the shaft orifice. After several punctures, the balloon deflated sufficiently to be withdrawn completely into the sheath which was then removed; groin haemostasis was achieved by m a n u a l pressure. The patient had normal pulses following the procedure and was asymptomatic at 3 m o n t h s follow up. tn 1985 Schneider et al. [1] reported three failures of angioplasty balloon deflation. In one, involving a 7-week-old mongrel puppy, they used a percutaneous 22 gauge Chiba needle to puncture and deflate the balloon; in another they passed an untapered 10 F catheter coaxially over the 6 F balloon catheter shaft up to the balloon which was then deflated by a sharp tug on its shaft. The technique used in our case seems a preferred option when a n a t o m y permits and a suitable sheath is in place; it avoids percutaneous Chiba needle puncture or placement of a large catheter. A. J. L I D D I C O A T M. S. T. R U T T L E Y
Department of Radiology University Hospital o f Wales Cardiff CF4 4 X W
Reference
1 Schneider JR, Johnsrude IS, Lund G, Rysavy J, Anderson RW, Amplatz K. Percutaneous catheter balloons; failure to deflate. Radiology 1985;155:832.
CT AND M R I O F T H E C A U D A EQUINA S Y N D R O M E IN ANKYLOSING SPONDYLITIS SIR In the article by Kerslake et al. [1] the plural of diverticulum is repeatedly spelled diverticulae and of foramen, foraminae. The correct plurals are, of course, diverticula and foramina. 1 realize that a knowledge of Latin is no longer a requirement for employment in an academic department but am surprised that the errors passed your editorial scrutiny. J. F. C A L D E R
Department of Radiology Victoria Infirmary Glasgow G42 9TY
Fig. 1.
This PTC was performed one year after percutaneous placement of a l0 French 'double m u s h r o o m ' stent through an obstructing cholangio carcinoma. The patient had suffered intermittent cholangitis and ultimately a return of jaundice and itch. The radiograph shows the stent to be occluded and fractured in two sites. P. R. B E L L A M Y
Reference
1 Kerslake RW, Mitchell LA, Worthington BS. Case Report: C T and M R I of the cauda equina syndrome in ankylosing spondylitis. Clinical Radiology 1992;45:134-136.
Radiology Department Wellington Hospital Newtown Wellington South 6002 New Zealand
Reference
BROKEN C H O L E D O C H A L S T E N T SIR I was interested to read the case report by Zissin et al. [1] describing a broken intracholedochal stent. Figure 1 depicts a similar situation.
I Zissin R, Novis B, Rubinstein Z. Case Report: Broken intracholedochai stent. Clinical Radiology 1992;45:46 47.
CLINICAL RADIOLOGY
9 Caro J J, Trindade E, McGregor M. The risks of death and severe non-fatal reactions with high versus low osmolality contrast media; A meta-analysis. American Journal of Radiology 1991; t 56:825-832. 10 K a t a y a m a H, Yamaguchi K, Kozuka T, Takashima T, Seez P, Matsuura Ki A report from the Japanese Committee on the safety of contrast media. Radiology 1990;175:621 628.
SiR 1 wish to thank Professor Grainger for his comments on 'Deep venous thrombosis following iopamidol venography'. He has considerably broadened the discussion to make several observations regarding the selection of contrast media for venography which are of interest. l would like to respond to some of the points raised: 1 Low Osmolar Contrast Media (LOCM) have clearly been shown to have superior clinical tolerance to High Osmolar Contrast Media (HOCM) [1] and to produce less phlebographic venous thrombosis [2] and it is the extreme rarity of clinically significant thrombosis with L O C M which makes this case interesting. 2 Diagnostic images can be obtained in most cases with diluted contrast media, but the need to dilute contrast has not been clearly established. Iopamidol 300 is specifically recommended by the manufacturer for venography (Merck Data Sheet), and is, I suspect, commonly used in clinical practice. A very recent radiological text [3] recommends that for venography 'If ionic agents have to be used then it is advisable that they be diluted to bring their osmolality closer to that of plasma'. I presume that this refers to H O C M and implies that non-ionic agents do not have to be diluted, although the same chapter does recommend slight dilution for lower limb venography '60 to I00 ml of contrast media (preferably a low osmolar or non-ionic medium; approx. 250 m g l/ml)'. 3 Professor Grainger's statement that admixture of blood and contrast in the syringe 'may well have occurred and caused the massive phlebothrombosis' is unjustifiable since, as stated in the article, 'It is our policy to flush the injection system with normal saline before and after contrast administration, and not to allow the mixing of blood and contrast in the syringe during angiography'. 4 Low osmolality and non-ionicity are not synonymous and I do not equate them. The discussion must be read in context and is specifically related to a complication of a non-ionic contrast iopamidol. Nonionic contrast media do have low osmolality. The concern about the tendency of blood to coagulate in the presence of contrast refers to non-ionic contrast media and not all LOCM. The decreased complications with iopamidol noted by Lea T h o m a s et al. [2] are related to conventional high osmolar ionic contrast media commonly used at that time for venography and do not, of course, apply to ioxaglate.
that shown in Fig. 4 of the article by McNicholas and associates, Our series of orbital pseudotumours increased to 43 by 1988, when this problem was extensively described [3]. There did appear to be a slight clinical difference, particularly regarding outcome, between the anterior and the diffuse group. l wonder whether Dr McNicholas and associates would note any clinical or outcome difference in their diffuse category if they were to divide them based on those patients who appear to have more specific anterior involvement. R. A. N U G E N T
Vancouver General Hospital British Columbia's Health Sciences Centre Vancouver B.C. V5Z IM9 Canada
References
I McNicholas M M J , Power W J, Griffin JF. Idiopathic inflammatory pseudotumour of the orbit: C T features correlated with clinical outcome. Clinical Radiology 1991;44:3 7. 2 Nugent RA, R o o t m a n J, Robertson WD, Lapointe JS, Harrison PB. Acute orbital pseudotumours: classification and CT features. American Journal of Neuroradiology 1981;2:431 436. 3 R o o t m a n J. Diseases of the orbit. Philadelphia: J.B. Lippincott Company, 1988:159 175.
SiR - We thank Dr Nugent for his interest in our article. We note the extra category of anterior pseudotumour which he described in his article [1]. The only case in our series which resembled this category was Case 13 which is shown in Fig. 4. This patient however had evidence of myositis and an inflammatory mass on a subsequent scan and we included him in our diffuse category. All five patients in this category were difficult to manage. All had recurrent disease and required second line treatment. The case in question required immunosuppression and irradiation and still requires treatment with steroids. Perhaps with a larger series it might be possible to demonstrate a difference in response between patients with diffuse disease and patients with disease affecting only the posterior scleral margin and adjacent optic nerve. In our series we had no patient who fitted exactly into this category and so we cannot c o m m e n t on differences in clinical outcome which might be evident between groups. M. M. J. M c N I C H O L A S
I am confident that the readers of this Journal are well aware of the difference between non-ionicity and low osmolality and will not be 'seriously mislead' by my discussion. L. H. COPE
South Tyneside Distriet Hospital Harton Lane South Shields Tyne and Wear NE34 OPL
Department of Diagnostic Imaging St Vincent's Hospital Elm Park Dublin 4
.Reference
1 Nugent RA, R o o t m a n J, Robertson WD, Lapointc JS, Harrison PB. Acute orbital pseudotumours: classification and CT features. American Journal o)c Roentgenology 1981;137:957-962.
References
1 Grainger RG, Dawson P. Low osmolar contrast media: an appraisal. Clinical Radiology 1990;42:1 5. 2 Lea T h o m a s M, Kealing FP, Piaggio RB, Treweeke PS. Contrast agent induced thrombophlebitis following leg phlebography: Iopamidol versus meglumine iothalamate. British Journal of Radiology 1984;57:205 207. 3 Grainger RG, Allison D J, eds. Diagnostic Radiology. Churchill Livingstone, 1992:2278 2299.
INFLAMMATORY
PSEUDOTUMOUR
OF ORBIT
S l ~ - 1 read with interest the article by M. J. J. McNicholas and associates entitled 'Idiopathic inflammatory pseudotumour of the orbit: CT features correlated with clinical outcome' [I]. The authors categorize these patients into four CT groups. In 1981, we categorized sixteen patients into five groups [2]. Four of these were the same as those used by the above authors, with the fifth category being the anterior group. The anterior pseudotumours involve the posterior scleral margin, usually with posterior extension along the adjacent optic nerve. The appearance, in fact, is somewhat similar to
DEFLATING
AN ANGIOPLASTY
BALLOON
SIR - We wish to report a complication of percutaneous transluminal angioplasty and its management. A 70-year-old w o m a n with 50 yard claudication and a right c o m m o n iliac stenosis (70% diam.) underwent right c o m m o n iliac angioplasty. The right c o m m o n femoral artery was punctured and the lesion crossed with a 0.035 in diam. straight guide wire. A 6 French (F) sheath was inserted and a 5F 4cm 8ram diam. balloon catheter (AXM5/35/80/8/4, William Cook) was passed through this and across the stenosis. The 0.035 in wire was replaced with one of 0.025 in diameter through a Tuohy Borst Y connector to allow catheter flushing and manometry. A trans 'stenotic' gradient of 25 m m H g was measured between the catheter tip and the sheath side arm. The balloon was inflated with an equal parts mixture of Ioxaglate 320 and normal saline at 7 atm pressure for 1 rain, during which the 'waist' effect of the stenosis was abolished. Following this single inflation the balloon could not be deflated despite full negative pressure with a 50ml syringe. Despite the failure of deflation, gentle traction on the catheter shaft moved the balloon (still under negative pressure) without apparent resistance. The 10 cm sheath was therefore advanced as far as possible and the balloon slowly withdrawn, still under negative pressure, until it obstructed the sheath orifice.
149
CORRESPONDENCE Catheter tip pressure recording during this showed no gradient across the angioplasty site and a digital subtraction arteriogram (contrast injected through the balloon catheter tip) showed no residual stenosis or apparent damage along the track of the balloon withdrawal. The course of the external iliac artery c o m m o n femoral artery was relatively straight and therefore, with balloon and sheath held together by gentle pull and push respectively, the stilette of a 22 gauge Chiba needle was passed through the sheath parallel to the balloon catheter shaft to puncture the balloon at the shaft orifice. After several punctures, the balloon deflated sufficiently to be withdrawn completely into the sheath which was then removed; groin haemostasis was achieved by m a n u a l pressure. The patient had normal pulses following the procedure and was asymptomatic at 3 m o n t h s follow up. tn 1985 Schneider et al. [1] reported three failures of angioplasty balloon deflation. In one, involving a 7-week-old mongrel puppy, they used a percutaneous 22 gauge Chiba needle to puncture and deflate the balloon; in another they passed an untapered 10 F catheter coaxially over the 6 F balloon catheter shaft up to the balloon which was then deflated by a sharp tug on its shaft. The technique used in our case seems a preferred option when a n a t o m y permits and a suitable sheath is in place; it avoids percutaneous Chiba needle puncture or placement of a large catheter. A. J. L I D D I C O A T M. S. T. R U T T L E Y
Department of Radiology University Hospital o f Wales Cardiff CF4 4 X W
Reference
1 Schneider JR, Johnsrude IS, Lund G, Rysavy J, Anderson RW, Amplatz K. Percutaneous catheter balloons; failure to deflate. Radiology 1985;155:832.
CT AND M R I O F T H E C A U D A EQUINA S Y N D R O M E IN ANKYLOSING SPONDYLITIS SIR In the article by Kerslake et al. [1] the plural of diverticulum is repeatedly spelled diverticulae and of foramen, foraminae. The correct plurals are, of course, diverticula and foramina. 1 realize that a knowledge of Latin is no longer a requirement for employment in an academic department but am surprised that the errors passed your editorial scrutiny. J. F. C A L D E R
Department of Radiology Victoria Infirmary Glasgow G42 9TY
Fig. 1.
This PTC was performed one year after percutaneous placement of a l0 French 'double m u s h r o o m ' stent through an obstructing cholangio carcinoma. The patient had suffered intermittent cholangitis and ultimately a return of jaundice and itch. The radiograph shows the stent to be occluded and fractured in two sites. P. R. B E L L A M Y
Reference
1 Kerslake RW, Mitchell LA, Worthington BS. Case Report: C T and M R I of the cauda equina syndrome in ankylosing spondylitis. Clinical Radiology 1992;45:134-136.
Radiology Department Wellington Hospital Newtown Wellington South 6002 New Zealand
Reference
BROKEN C H O L E D O C H A L S T E N T SIR I was interested to read the case report by Zissin et al. [1] describing a broken intracholedochal stent. Figure 1 depicts a similar situation.
I Zissin R, Novis B, Rubinstein Z. Case Report: Broken intracholedochai stent. Clinical Radiology 1992;45:46 47.
