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Renal Transplant Dysfunction: MR Evaluation
.208
PEDIATRIC UROLOGY
Renal Transplant Dysfunction: MR Evaluation Z. WINSETT, E.G. AMPARO, H. D. FAWCETT, R. KUMAR, R. F. JOHNSON, JR., D. G. BEDI AND 0. E. WINSETT, Departments of Radiology and Surgery, University of Texas Medical Branch, Galveston, Texas
M.
Amer. J. Roentgen., 150: 319-323, 1988 The results of 45 MR examinations were prospectively compared with the clinical course and biopsy results in 38 renal transplant patients to determine the role of MR in evaluating allograft dysfunction. Twenty-six patients underwent allograft biopsy. In eight patients in whom the biopsy was performed more than 48 hr after MR examination and in 19 patients who did not have a biopsy, the subsequent clinical course was sufficiently diagnostic to determine the specific cause of the transplant dysfunction. Corticomedullary differentiation, graded from O to 3, was not helpful in separating rejection (n = 20) from acute tubular necrosis (n = 9), drug toxicity (n = 7), pyelonephritis (n = 2), or normal grafts (n = 7) because of overlap between groups (sensitivity= 60%, specificity= 60%). In the six patients with two or more MR studies, serial changes in corticomedullary differentiation were not consistent and could not be used to diagnose rejection. When any abnormality of allograft sinus fat, size or shape, or corticomedullary differentiation was considered, the sensitivity for the diagnosis of rejection approached 80%; however, specificity was low (48%). We conclude that MR imaging is not sufficiently accurate to replace transplant biopsy and therefore has a limited role in the evaluation of transplant dysfunction.
the excretory urogram, radionuclide studies and, most recently, ultrasound all have been shown to be in varying degrees sensitive to identify the presence of an abnormality but they are far from specific. With the advent of MRI the proponents of this new modality claimed it to be tissue-specific in patients with transplanted kidneys. These studies clearly show that the technique is not specific. Mitchell and associates, for example, report that corticomedullary differentiation was lost in acute rejection (7 of 12 patients) but also in acute tubular necrosis (2 of 6) and cyclosporine toxicity (2 of 3). Even more disturbing was that this sign was not present in 5 of 6 patients with mild rejection. Similarly, Winsett and associates report only a 60 per cent sensitivity and 60 per cent specificity (38 transplant patients). This is our belief as well and it is not surprising to us because current imaging devices do not yet have the pathological specificity of the microscope. This being the case, we advocate first using the less expensive modalities, such as ultrasound or nuclear medicine. The routine use of MRI should be reserved until it clearly can be shown to be so sensitive as to justify the added expense, and in select difficult cases. As to which modality to start with, one should consider ultrasound, since it usually is cheaper. However, factors, such as availability and the expertise of the evaluating physician, also are important determinants. It should be noted that in many cases at least 2 of the 3 studies are performed to confirm the clinical impression. Stanford M. Goldman, M.D.
Acute Renal Allograft Rejection: Difficulty in Diagnosis of Histologically Mild Cases by MR Imaging MITCHELL, A. M. ROZA, C. E. SPRITZER, H. POLLACK, P. H. ARGER, A. ALAVI, D. JORKASKY, C. F. BARKER, J. TOMASZEWSKI, A. NAJI, L. J. PERLOFF AND H. Y. KRESSEL,
D.
PEDIATRIC UROLOGY
G.
Departments of Radiology, Medicine and Pathology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
J. Comput. Assist. Tomogr., 11: 655-663, 1987 A total of 33 magnetic resonance imaging (MRI) examinations was performed on 28 patients to evaluate acute allograft rejection. In 17 studies there was biopsy correlation. The studies also were correlated with radionuclide interpretations in 22 instances. The study particularly evaluated cortical medullary differentiation on Tl-weighted images, visibility of intrarenal vessels and renal volume. The most common finding in acute rejection was that of diminished cortical medullary differentiation, which was present in 7 of 12 cases but, unfortunately, also was seen in acute tubular necrosis (2 of 6) and cyclosporine toxicity (2 of 3). It was present in all cases of severe acute rejection but it was not present in 5 of 6 with mild rejection. Thus, MRI is not sensitive or specific to diagnose mild acute rejection.
Editorial Comment: Institutions with transplant services are constantly facing the diagnostic dilemma as to the etiology of a nonfunctioning or poorly functioning renal transplant. Most significant is the differentiation of rejection from tubular necrosis and from cyclosporine toxicity. Through the years various imaging modalities have been touted as virtually diagnostic in differentiating these entities only to be proved to be nonspecific after more careful analysis. Unfortuantely, with time
Long-Term Outcome of Boys With Posterior Urethral Valves
H.
F. PARKHOUSE, T. M. BARRATT, M. J. DILLON, P. G. DUFFY, J. FAY, P. G. RANSLEY, C. R. J. WOODHOUSE AND D. I. WILLIAMS, Department of Paediatric Nephrology, Insti-
tute of Child Health; Department of Urology and Renal Unit, Hospital for Sick Children, and Department of Paediatric Urology, St. Peter's Hospitals Group, London, England Brit. J. Urol., 62: 59-62, 1988 One hundred and fourteen boys with posterior urethral valves were treated between 1966 and 1975. Four died during the first hospital admission, 6 died from renal failure during childhood, 1 died from other causes and 15 were lost to follow-up. Eightyeight were reviewed 11 to 22 years after diagnosis and the renal outcome of 98 patients is therefore known. Approximately onethird of patients presented under 1 month of age, between 1 month and 1 year, and over 1 year respectively. Bilateral vesicoureteric reflux was observed in one-quarter of the boys, more frequently in those presenting in the first month of life. Half of the patients were treated by primary valve ablation and half underwent temporary upper tract diversion: the outcome was worse for the diverted group. One-third of the boys had a long-term bad outcome for renal function. This outcome was associated with early presentation, bilateral vesicoureteric reflux and day-time urinary incontinence after the age of 5 years. The association of bad outcome with incontinence points to continuing bladder dysfunction as a major determinant of long-term outcome for renal function.
PEDIATRIC UROLOGY
Renal Transplant Dysfunction: MR Evaluation Z. WINSETT, E.G. AMPARO, H. D. FAWCETT, R. KUMAR, R. F. JOHNSON, JR., D. G. BEDI AND 0. E. WINSETT, Departments of Radiology and Surgery, University of Texas Medical Branch, Galveston, Texas
M.
Amer. J. Roentgen., 150: 319-323, 1988 The results of 45 MR examinations were prospectively compared with the clinical course and biopsy results in 38 renal transplant patients to determine the role of MR in evaluating allograft dysfunction. Twenty-six patients underwent allograft biopsy. In eight patients in whom the biopsy was performed more than 48 hr after MR examination and in 19 patients who did not have a biopsy, the subsequent clinical course was sufficiently diagnostic to determine the specific cause of the transplant dysfunction. Corticomedullary differentiation, graded from O to 3, was not helpful in separating rejection (n = 20) from acute tubular necrosis (n = 9), drug toxicity (n = 7), pyelonephritis (n = 2), or normal grafts (n = 7) because of overlap between groups (sensitivity= 60%, specificity= 60%). In the six patients with two or more MR studies, serial changes in corticomedullary differentiation were not consistent and could not be used to diagnose rejection. When any abnormality of allograft sinus fat, size or shape, or corticomedullary differentiation was considered, the sensitivity for the diagnosis of rejection approached 80%; however, specificity was low (48%). We conclude that MR imaging is not sufficiently accurate to replace transplant biopsy and therefore has a limited role in the evaluation of transplant dysfunction.
the excretory urogram, radionuclide studies and, most recently, ultrasound all have been shown to be in varying degrees sensitive to identify the presence of an abnormality but they are far from specific. With the advent of MRI the proponents of this new modality claimed it to be tissue-specific in patients with transplanted kidneys. These studies clearly show that the technique is not specific. Mitchell and associates, for example, report that corticomedullary differentiation was lost in acute rejection (7 of 12 patients) but also in acute tubular necrosis (2 of 6) and cyclosporine toxicity (2 of 3). Even more disturbing was that this sign was not present in 5 of 6 patients with mild rejection. Similarly, Winsett and associates report only a 60 per cent sensitivity and 60 per cent specificity (38 transplant patients). This is our belief as well and it is not surprising to us because current imaging devices do not yet have the pathological specificity of the microscope. This being the case, we advocate first using the less expensive modalities, such as ultrasound or nuclear medicine. The routine use of MRI should be reserved until it clearly can be shown to be so sensitive as to justify the added expense, and in select difficult cases. As to which modality to start with, one should consider ultrasound, since it usually is cheaper. However, factors, such as availability and the expertise of the evaluating physician, also are important determinants. It should be noted that in many cases at least 2 of the 3 studies are performed to confirm the clinical impression. Stanford M. Goldman, M.D.
Acute Renal Allograft Rejection: Difficulty in Diagnosis of Histologically Mild Cases by MR Imaging MITCHELL, A. M. ROZA, C. E. SPRITZER, H. POLLACK, P. H. ARGER, A. ALAVI, D. JORKASKY, C. F. BARKER, J. TOMASZEWSKI, A. NAJI, L. J. PERLOFF AND H. Y. KRESSEL,
D.
PEDIATRIC UROLOGY
G.
Departments of Radiology, Medicine and Pathology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
J. Comput. Assist. Tomogr., 11: 655-663, 1987 A total of 33 magnetic resonance imaging (MRI) examinations was performed on 28 patients to evaluate acute allograft rejection. In 17 studies there was biopsy correlation. The studies also were correlated with radionuclide interpretations in 22 instances. The study particularly evaluated cortical medullary differentiation on Tl-weighted images, visibility of intrarenal vessels and renal volume. The most common finding in acute rejection was that of diminished cortical medullary differentiation, which was present in 7 of 12 cases but, unfortunately, also was seen in acute tubular necrosis (2 of 6) and cyclosporine toxicity (2 of 3). It was present in all cases of severe acute rejection but it was not present in 5 of 6 with mild rejection. Thus, MRI is not sensitive or specific to diagnose mild acute rejection.
Editorial Comment: Institutions with transplant services are constantly facing the diagnostic dilemma as to the etiology of a nonfunctioning or poorly functioning renal transplant. Most significant is the differentiation of rejection from tubular necrosis and from cyclosporine toxicity. Through the years various imaging modalities have been touted as virtually diagnostic in differentiating these entities only to be proved to be nonspecific after more careful analysis. Unfortuantely, with time
Long-Term Outcome of Boys With Posterior Urethral Valves
H.
F. PARKHOUSE, T. M. BARRATT, M. J. DILLON, P. G. DUFFY, J. FAY, P. G. RANSLEY, C. R. J. WOODHOUSE AND D. I. WILLIAMS, Department of Paediatric Nephrology, Insti-
tute of Child Health; Department of Urology and Renal Unit, Hospital for Sick Children, and Department of Paediatric Urology, St. Peter's Hospitals Group, London, England Brit. J. Urol., 62: 59-62, 1988 One hundred and fourteen boys with posterior urethral valves were treated between 1966 and 1975. Four died during the first hospital admission, 6 died from renal failure during childhood, 1 died from other causes and 15 were lost to follow-up. Eightyeight were reviewed 11 to 22 years after diagnosis and the renal outcome of 98 patients is therefore known. Approximately onethird of patients presented under 1 month of age, between 1 month and 1 year, and over 1 year respectively. Bilateral vesicoureteric reflux was observed in one-quarter of the boys, more frequently in those presenting in the first month of life. Half of the patients were treated by primary valve ablation and half underwent temporary upper tract diversion: the outcome was worse for the diverted group. One-third of the boys had a long-term bad outcome for renal function. This outcome was associated with early presentation, bilateral vesicoureteric reflux and day-time urinary incontinence after the age of 5 years. The association of bad outcome with incontinence points to continuing bladder dysfunction as a major determinant of long-term outcome for renal function.