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Biomedical subjects

H C Irving

Publications and source records attributed to H C Irving.

At least 37 records · Page 2Linked to original sources
PubMed1993

Does the Whitaker test add to antegrade pyelography in the investigation of collecting system dilatation in renal allografts?

Significant pelvicalyceal dilatation in renal allografts is currently investigated by antegrade pyelography. However, the clinical significance of a radiologically demonstrated narrowing of the ureter is unclear. Over a 21-month period 26 of 155 renal allografts with pelvicalyceal dilatation were investigated by antegrade pyelography. In eight allografts no ureteric stenosis could be identified. Two grafts were shown to have ureteric necrosis and required surgical intervention and 16 of the other grafts appeared to have a ureteric stenosis. 15 of the 16 allografts with radiological ureteric stenosis underwent a concurrent pressure flow study to assess the functional relevance of the ureteric narrowing. As shown by a pressure rise of > 7 mmHg at a perfusion rate of 10 ml min-1, 11 of the 15 grafts were functionally obstructed and were treated by a nephrostomy catheter followed by antegrade insertion of a ureteric stent. The four grafts with a negative pressure flow study were subsequently shown on biopsy to have rejection. The diagnosis of allograft rejection was also confirmed by biopsy in seven of the eight allografts without a radiological ureteric stenosis. The last of the eight allografts was found to be cyclosporin toxic. Pelvicalyceal dilatation of renal allografts is appropriately investigated by antegrade pyelography in combination with a pressure flow study which identifies those grafts with mechanical obstruction.

Adult↗
PubMed1993

Improving the evaluation of renal transplant collecting system dilatation by computerized ultrasound image digitization.

43% of the renal allografts transplanted at our centre demonstrate pelvicalyceal dilatation on ultrasonography. However, only 6% of grafts are ultimately shown to be obstructed by antegrade pyelography. We have attempted to improve the specificity of ultrasonography by a quantitative analysis of 394 serial ultrasound studies from 150 renal transplant recipients. Representative images in the longitudinal and transverse axes were selected by a single observer for each of the studies and the outline of the kidney and its pelvicalyceal system was traced out. The images were then digitized using a Summagraphics tablet so that the length, width and area of the kidney and its pelvicalyceal system were calculated for each image. A step-wise discriminant analysis was performed which showed that the ratio of the area of the kidney to its pelvicalyceal area in both axes discriminated between normal, dilated but non-obstructed, and obstructed grafts. The median ratio of kidney to collecting system area in the obstructed grafts was 5.2 in the longitudinal and 4.4 in the transverse scan planes (vs median ratios of 32.8 and 22.0 for non-dilated grafts). Using canonical discriminant function, an index was derived which combines these ratios for the longitudinal and transverse images of the same kidney and this has further improved the diagnostic accuracy (median index of 2.45 in obstructed group vs -0.85 in non-dilated kidneys). This method improves upon the radiologist's report and identifies those grafts which require intervention.

Adolescent↗
PubMed1992

Complications of renal transplantation and the role of interventional radiology.

As rejection therapy has improved, the interventional complications of renal transplantation have increased in relative importance as potentially reversible causes of graft malfunction and failure. Ultrasonically guided aspiration and drainage techniques are essential for the characterization and subsequent management of perinephric fluid collections that occur in as many as 51% of cases, of which up to 18% may be clinically significant. In a series of 507 consecutive renal transplants, urological complications were seen in 9% of patients, consisting of ureteric obstruction in 6% and urinary leaks in 3%. Detection via ultrasound scanning, evaluation via antegrade pyelography and pressure-flow tests, and management via percutaneous nephrostomy and ureteric stenting all contribute to rapid diagnosis and subsequent treatment. Serial ultrasound scanning of renal transplants and the aggressive use of interventional radiological techniques are vital to the early detection and management of complications, and can lead to preservation of graft function and continued improvement in graft survival figures.

Graft Rejection↗
PubMed1992

Use of 99mtechnetium-dimercaptosuccinic acid to study patterns of renal damage associated with prenatally detected vesicoureteral reflux.

Static isotope imaging with 99mtechnetium-dimercaptosuccinic acid was performed at a mean age of 34 days in 32 children (50 kidneys) whose vesicoureteral reflux had been identified as a result of prenatal ultrasound scanning. Three patterns of isotope uptake were observed: 1) noninfected primary vesicoureteral reflux (15 children, 24 kidneys), 2) noninfected secondary (obstructed) vesicoureteral reflux (9 patients, 11 kidneys) and 3) infected primary reflux (8 infants, 15 kidneys). In 20 pattern 1 kidneys (83%) renal morphology and differential isotope were normal. In the 4 kidneys (17%) that showed evidence of impaired function this took the form of global parenchymal loss, that is small kidneys rather than focal scarring. In pattern 2 the combination of fetal vesicoureteral reflux and obstruction was a potent cause of renal damage with total or near total loss of function in 7 of 9 refluxing units associated with posterior urethral valves and in 2 kidneys with secondary ureteropelvic junction obstruction. Appearances of focal scarring were confined in pattern 3 and were found in 4 kidneys (27%). This overall incidence of detectable renal damage was lower than expected. Even when infection occurs, prenatal diagnosis may lessen the risk of scarring by enabling treatment to be instituted promptly. The findings suggest that uncomplicated primary vesicoureteral reflux is a relatively benign insult to the fetal kidney and that reflux nephropathy found in children presenting clinically is the result of infected vesicoureteral reflux in postnatal life. Any comparison of published studies will prove difficult until there is a more standardized approach to imaging technique and patient selection.

Female↗
PubMed1992

Ureteric complications of renal transplantation.

Of 507 consecutive recipients of renal allografts, 45 developed a urological complication. In 39 patients (7.7%) ureteric problems were implicated and these comprised 30 cases of obstruction and 9 cases of ureteric necrosis presenting as urinary leakage. In 7 patients ureteric obstruction resolved following a period of nephrostomy decompression; 10 patients were reconstructed surgically and this was successful in 8, with 2 patients requiring further surgical procedures. Ten patients were successfully treated by percutaneous stenting after dilatation of the stricture. Stenting failed in 4 patients and in 1 patient caused rupture of a calix. All 10 stents have now been removed and there is no recurrence of stricture (follow-up 32.0 +/- 8.6 months). Of the remaining 3 grafts, 2 were removed and the other graft had percutaneous removal of a ureteric calculus. The 1-year survival rate of allografts in the ureteric complication group was 84.6%; in the recipients without a urological complication it was 81%. It was concluded that an active approach to ureteric problems following renal transplantation results in the rescue of the majority of allografts.

Adolescent↗
PubMed1992

A tale of two prior probabilities--avoiding the false positive antenatal diagnosis of autosomal recessive polycystic kidney disease.

We describe a case in which the typical ultrasound diagnosis of infantile polycystic kidney in a woman with no family history of renal disease was not confirmed by histology following termination of the pregnancy. This is contrasted with the situation in another couple who were known carriers of autosomal recessive polycystic kidney disease and where the prenatal ultrasound diagnosis was confirmed histologically. When prior genetic risk is low, the possibility of a normal or less severe outcome must be discussed with parents when fetal ultrasound shows large, echogenic kidneys but normal amniotic fluid volume.

Diagnostic Errors↗
PubMed1992

Intrarenal Doppler ultrasound studies in normal and acutely obstructed kidneys.

Renal ultrasound examinations and intrarenal arterial Doppler studies were performed on 48 patients with normal renal tracts and 20 patients presenting with acute renal colic resulting from ureteric calculus, 14 of whom had urographic evidence of renal obstruction. The mean resistance index (RI) of the Doppler waveforms obtained on the 14 obstructed kidneys (70.4 +/- 6.22) was significantly higher than the mean RI of the 96 normal kidneys (62.4 +/- 6.43). The mean difference between the RIs of the obstructed kidneys and their contralateral non-obstructed kidneys (8.37 +/- 4.43) was also significantly higher than the differences in RI seen between pairs of normal kidneys (2.70 +/- 1.71). Five out of 14 obstructed kidneys showed no pelvicalyceal dilatation and could not have been shown to be obstructed on conventional sonography. Four of these five had RI changes suggestive of obstruction and thus 13 of 14 obstructed kidneys would have been identified as obstructed by a combination of Doppler and conventional sonographic findings. 10 of the 14 obstructed kidneys were re-examined after passage of a urinary calculus and nine showed a reduction in the RI of the previously obstructed kidneys. The 10th subsequently required ureterolithotomy.

Acute Disease↗
PubMed1992

Inability of color and spectral Doppler to identify fetal renal obstruction.

Color flow Doppler imaging was used to obtain fetal renal artery flow velocity waveforms in 130 normal fetuses at various gestational ages to build a database for the establishment of normal ranges for the Pulsatility Index in the fetal renal arteries throughout pregnancy. Twenty-nine cases of fetal renal tract dilation (greater than 5 mm anteroposterior diameter of the renal pelvis) of various causes were investigated. We found that measurements of the pulsatility index were not significantly altered from the normal range, so that color flow Doppler does not appear to be helpful in the differential diagnosis of fetal renal dilation.

Blood Flow Velocity↗
PubMed1992

Monitoring renal allograft rejection with duplex sonography.

Thirty-six renal allograft recipients were monitored by serial duplex Doppler ultrasound studies post-transplant and during early rejection. A separate reproducibility study demonstrated no significant inter- or intra-operator variability in measurements of resistive index of an interlobar artery (RI) (2.1% [1.5%] and 3.2% [2.3%] respectively, mean [standard error] of coefficients of variance). Twenty-one patients had rejection within 3 weeks of transplantation. These grafts showed greater overall rises in the RI, from day 2 to day 5 post-transplant, than the grafts which had no rejection. Eleven of the 21 patients required more than one course of methyl-prednisolone for persistent or recurring rejection. These grafts had higher RI on the day rejection was diagnosed (81 [7.3], median [interquartile range]) compared with the remaining 10 patients (68.6 [8.7]). The 11 grafts with persistent rejection had higher RI (p less than 0.005, Mann-Whitney U-test) on day 2 post-transplant (76 [3.9]) compared with the 10 grafts successfully treated with a single course of methyl-prednisolone (63.2 [10.9]). This study demonstrates that grafts with an RI of greater than 70 on day 2 post-transplant are likely to have rejection requiring additional treatment (sensitivity--100%, specificity--80%). These patients may be candidates for earlier or alternative anti-rejection therapy.

Adolescent↗
PubMed1991

Early computed colour echo Doppler imaging following renal transplantation.

Thirty patients with renal allografts were monitored for 15 postoperative days by colour-coded Doppler imaging and categorized as stable, rejection, acute tubular necrosis and cyclosporine toxicity. All forms of graft dysfunction showed significantly raised resistance (P less than 0.01) and pulsatility (P less than 0.01) indices (RI and PI, respectively). It was not possible to use Doppler imaging to differentiate the cause of graft dysfunction, but stable grafts in patients with high cyclosporin levels had significantly higher RI (P less than 0.04) and PI (P less than 0.04) than similar grafts in patients with cyclosporine levels in the therapeutic range.

Adolescent↗
PubMed1991

Ultrasonography of renal allografts: collecting system dilatation and its clinical significance.

Reports and ultrasound scans (658 studies) of 135 renal allografts, transplanted in the years 1987 and 1988, have been reviewed. Records of the recipients were also studied in order to determine the clinical status of the kidney at the time of each ultrasound examination and to obtain long-term follow-up of allograft function. Seventy-seven allografts (57%) never showed pelvicalyceal dilatation on 342 serial examinations. Forty-two kidneys (31%) had mild dilatation reported on at least one scan, which did not progress. However, 11 mildly dilated allografts developed moderate to severe dilatation on later examinations and these, together with 5 allografts reported as exhibiting moderate to severe hydronephrosis on their first dilated scan, were classed as moderate to severe (n = 16 = 12%). Thirty-eight patients (90%) with mild dilatation of the collecting system had no evidence of obstruction. However, in allografts with moderate to severe dilatation and poor or deteriorating function, ten patients (70%) were found to have ureteric obstruction. There was no significant difference in 1-year graft survival (87% versus 81.8%) and the median serum creatinine at 3 and 12 months after transplantation between non obstructed 'dilated' and non-dilated allografts (149 mumol/l versus 153.7 mumol/l; 139 mumol/l versus 147.3 mumol/l). All 14 obstructed allografts were salvaged with a graft survival of 85.7% at 1 year. Median serum creatine in these patients was significantly elevated at 200 mumol/l and 189 mumol/l at 3 and 12 months; P = 0.05 and 0.01 compared to dilated non-obstructed allografts. Our results indicate that grafts with moderate to severe dilatation should be urgently investigated to minimise further allograft damage.

Adult↗
PubMed1991

Antenatally detected pelviureteric junction obstruction. Is non-operation safe?

We report follow-up data (minimum of 1 year) on 63 kidneys with antenatally detected pelviureteric junction obstruction, as defined by renographic criteria. The condition was bilateral in 10 patients (i.e. 20 kidneys), 2 patients had unilateral obstruction with contralateral multicystic dysplastic kidneys, and 41 patients had unilateral obstruction with a normal contralateral kidney. In the latter group, 29 (71%) had good function (greater than 40%) at initial assessment. Of the 63 kidneys, 24 (38%) were operated upon following initial assessment, mainly for impaired function. Of 39 patients, initially managed non-operatively, 8 (21%) were operated upon subsequently: 3 for deteriorating function (2 of whom have been reassessed and both have regained their lost function) and 5 for other renographic or ultrasonic indications). Of the original 63 kidneys, 31 (49%) continue to be managed non-operatively; 16 of these (52%) show improving ultrasound appearances, 8 of 17 studied show improved drainage, and all unilateral cases have stable good function. It is concluded that non-operative management of selected cases of antenatally detected pelviureteric junction obstruction is safe.

Female↗
PubMed1991

Role of duplex imaging and fine needle aspiration cytology of renal allografts in monitoring response to anti-rejection therapy.

The role of duplex imaging and fine-needle aspiration cytology (FNAC) in monitoring the response to anti-rejection therapy was investigated in 14 of the 22 rejection episodes which occurred in 30 renal allografts recipients. In 9 of these 14 episodes of rejection, with good resolution, both resistive (RI) and pulsatility (PI) indices decreased by significant proportions (p less than 0.05). The FNAC scores also fell significantly with anti-rejection therapy. In 5 other episodes of rejection where the graft continued to deteriorate there was no significant fall of RI and PI (p greater than or equal to 0.2). In a small group of patients, both FNAC and Doppler predicted rejection. In conclusion, both duplex imaging and FNAC have a role in selection and optimal modulation of drugs in the treatment of acute renal allograft rejection.

Adolescent↗
PubMed1990

Prenatally diagnosed reflux: a follow-up study.

This report analyses the characteristics and outcome of 25 infants with vesicoureteric reflux detected prenatally on the basis of dilatation of the fetal urinary tract. Sixteen infants had bilateral reflux--a total of 41 refluxing units. The high proportion of males (84%) contrasts with clinically presenting reflux, which is dominated by females. Prenatally diagnosed reflux is generally of a higher grade--usually grade IV. Eight children (32%) had coexistent congenital abnormalities. Chemoprophylaxis was completely effective in 17 children (68%), who remained infection-free; 3 children (12%) had a single urinary infection and were managed conservatively whilst 5 (20%) experienced 2 or more infections and required reimplantation or vesicostomy. Spontaneous cessation of reflux was observed in 6 (35%) of 17 refluxing ureters reassessed after a mean interval of 2.1 years. The significance of isotope findings was sometimes difficult to assess but results in 30 refluxing units support the concept that focal renal scarring is usually a consequence of infected reflux in postnatal life.

Female↗
PubMed1990

Fetal choroid plexus cysts: a report of 100 cases.

A prospective study was undertaken to evaluate the prevalence and significance of fetal choroid plexus cysts detected on screening ultrasound (US) scans. One hundred cases of fetal choroid plexus cysts were detected from 11,700 examinations: There were 95 healthy newborns, three newborns with trisomy 18, one newborn with syndactyly of the toes, and one intrauterine death. In the three neonates with trisomy 18 the cysts were large (greater than 1 cm in diameter), and additional abnormalities were detected. Although there is a clear association between fetal choroid plexus cysts and trisomy 18, amniocentesis or chorionic villus sampling should be reserved for high-risk patients with either large cysts or US evidence of other abnormalities.

Brain Diseases↗
PubMed1989

Bilateral fetal uropathy: what is the outlook?

OBJECTIVE: To assess the morbidity and mortality associated with a prenatal diagnosis of bilateral fetal uropathy. DESIGN: Retrospective study. SETTING: Departments of radiology, paediatric surgery, obstetrics, and pathology in two teaching hospitals that serve as referral centres for the Yorkshire region. PATIENTS: 126 Cases of fetal uropathy were referred either prenatally or postnatally from hospitals in Yorkshire between August 1982 and December 1987. The disease was bilateral in 54 cases and unilateral in 72 cases. In 14 cases bilateral fetal uropathy was associated with coexistent disease. INTERVENTIONS: All cases were managed individually by an obstetrician after discussion with the radiologists and paediatric surgeons. Babies who survived were treated prophylactically with antibiotics after delivery and were operated on if appropriate. END POINT: Assessment of prognosis for long term renal function for each baby referred between August 1982 and December 1987: follow up ranged from six months to five years. MEASUREMENTS AND MAIN RESULTS: Of the 54 fetuses with bilateral fetal uropathy, 13 were terminated as the prenatal findings of ultrasonography were considered to be incompatible with long term survival. Ten of the liveborn babies died, five of renal or pulmonary insufficiency, or both, and five of associated congenital anomalies. Thirty one infants survived to follow up; four of these had serious coexistent disease and two had impaired renal function. Thus the overall mortality was 43% and the morbidity rate 19%. The renal anomaly was associated with other serious disease in 14 cases (26%) compared with two (3%) of the 72 cases of unilateral fetal uropathy. All but two of the 27 infants with isolated bilateral urinary tract disease had excellent prospects for survival. CONCLUSION: Although bilateral fetal uropathy is associated with a high morbidity rate and mortality, careful prenatal assessment can help to identify fetuses with a poor prognosis. The outlook for a fetus with isolated renal disease if treated promptly after delivery is excellent and compares favourably with that reported after prenatal surgical intervention.

Abnormalities, Multiple↗