Suspected iatrogenic ureteric injury: an approach to diagnostic imaging.

Iatrogenic ureteric injury (IUI) is the leading cause of ureteric trauma and a complication of major abdominal and pelvic surgery. IUI carries significant morbidity and mortality, which can be further compounded by delayed diagnosis due to its non-specific clinical presentation. We review ureteric anatomy, types of IUI, and imaging strategies available for diagnosis. We propose an imaging protocol for prompt diagnosis and follow-up.

Adenomatous-Dominant Benign Prostatic Hyperplasia (AdBPH) as a Predictor for Clinical Success Following Prostate Artery Embolization: An Age-Matched Case-Control Study.

PURPOSE: To investigate the clinical impact of performing prostate artery embolization (PAE) on patients with adenomatous-dominant benign prostatic hyperplasia (AdBPH). MATERIALS AND METHODS: Twelve patients from the ongoing proSTatic aRtery EmbolizAtion for the treatMent of benign prostatic hyperplasia (STREAM) trial were identified as having AdBPH; defined as two or more adenomas within the central gland of ≥1 cm diameter on multi-parametric MRI (MP-MRI). These patients were age-matched with patients from the STREAM cohort, without AdBPH. Patients were followed up with repeat MP-MRI at 3 months and 1 year. International prostate symptom score (IPSS), international index for erectile function (IIEF), and quality of life assessment from the IPSS and EQ-5D-5S questionnaires were recorded pre-PAE and at 6 weeks, 3 months, and 1 year. RESULTS: The mean age of patients was 68 (61-76). All patients had PAE as a day-case procedure. The technical success in the cohort was 23/24 (96%). There was a significant reduction in prostate volume following embolization with a median reduction of 34% (30-55) in the AdBPH group, compared to a mean volume reduction of 22% (9-44) in the non-AdBPH group (p = 0.04). There was a significant reduction in IPSS in the AdBPH group following PAE when compared with the control group [AdBPH median IPSS 8 (3-15) vs. non-AdBPH median IPSS 13 (8-18), p = 0.01]. IPSS QOL scores significantly improved in the AdBPH group (p = 0.007). There was no deterioration in sexual function in either group post-PAE. CONCLUSIONS: This is the first time that AdBPH has been identified as being a predictor of clinical success following PAE.

A growth-limiting, mild zinc-deficiency syndrome in some southern Ontario boys with low height percentiles.

A double-blind, pair-matched 12-mo study examined the effects of a zinc supplement (10 mg Zn/d as ZnSO4) on linear growth, taste acuity, attention span, biochemical indices, and energy intakes of 60 boys (aged 5-7 y) with height less than or equal to 15th and midparent height greater than 25th percentiles. Boys with initial hair Zn less than 1.68 mumol/g (n = 16) had a lower mean (+/- SD) weight-for-age Z score (-0.44 +/- 0.59 vs -0.08 +/- 0.84), and a higher median recognition threshold for salt (15 vs 7.5 mmol; p = 0.02) than those with hair Zn greater than 1.68 mumol/g. Only boys with hair Zn less than 1.68 mumol/g responded to the Zn supplement with a higher mean change in height-for-age Z score (p less than 0.05); taste acuity, energy intakes, and attention span were unaffected. A growth-limiting Zn deficiency syndrome exists in boys with low height percentiles, hair Zn levels less than 1.68 mumol/g, and impaired taste acuity.

Pulmonary thallium-201 uptake following dipyridamole-exercise combination compared with single modality stress testing.

Angiographic and clinical determinants of pulmonary uptake of thallium-201 were assessed in a laboratory setting where supine bicycle exercise is used for stress testing in the absence of limiting pharmacologic or physical factors, and where symptom-limited exercise is added to intravenous dipyridamole infusion in other cases. Angiographic correlation was available in 400 patients, including 130 tested with exercise, 94 in whom only handgrip or abbreviated bicycle exercise could be used after dipyridamole, and 176 in whom intravenous dipyridamole was combined with a significant level of exercise. For each test mode, lung/myocardial ratios on the immediate image were highly correlated (p less than or equal to 0.001) with a score based on the number of critical coronary artery stenoses, with grading by contrast ventriculography, and with the number of stenosed (greater than or equal to 50%) arteries; relationships (p less than 0.05) to history of myocardial infarction and to gender were also present. Multiple regression analysis showed the critical stenosis score and ventricular dysfunction to be the only significant determinants. When dipyridamole based tests were compared with exercise, curves of receiver-operating characteristics showed a tendency to better diagnostic performance. When dipyridamole is incorporated in stress testing, the value of increased lung uptake as an ancillary diagnostic sign is similar to that established for exercise.

Improved long-term survival following myocardial revascularization in patients with severe left ventricular dysfunction.

The natural history of patients with coronary artery disease associated with poor left ventricular (LV) function is dismal. This report analyzes the efficacy of myocardial revascularization in this subset of patients with coronary artery disease manifesting severe LV dysfunction on the basis of LV angiography, LV ejection fraction (LVEF), and left ventricular end-diastolic pressure (LVEDP). For the 2 1/2 year period ending November, 1977, 59 consecutive patients with coronary artery disease complicated by severe LV dysfunction underwent aorta-coronary bypass at the University of Western Ontario. All patients had angina refractory to medical therapy. Objective criteria for compromised LV function included the presence of three or more dysfunctional (hypokinetic of akinetic) segments on biplane LV angiography. Eighty-three percent (49/59) of patients had triple-vessel coronary artery disease. The mean LVEF for the series was 0.28 and the mean LVEDP was 18 mm Hg. The duration of follow-up was 24 to 60 months (mean 37 months), with follow-up survival data available on 100% of patients. The hospital mortality was 1.7% (1/59), and there were nine late deaths. The 5 year actuarial survival rate (+/- SEM) was 80% +/- 6%. Of the 44 long-term survivors available for direct assessment, 98% (43/44) report improvement with respect to angina and 66% (29/44) are totally asymptomatic. Eighty percent (28/35) of the long-term survivors under the age of 65 years are currently employed. These results indicate that myocardial revascularization can be performed in patients with severe ischemic LV dysfunction at very low risk and, further, that operation results in a dramatic improvement in survival expectations compared with optimal medical therapy.

Hepatic blood flow and metabolism.

The relationship between liver blood flow and hepatic metabolism remains unclear. An animal model as well as a methodology that permits simultaneous assessment of both of these functions are proposed. Several fractions of inspired oxygen were used to produce arterial oxygen levels commonly seen in clinical practice; these ranged from hyperoxemia to established hypoxemia. Over this range there were no considerable changes in transhepatic blood flow, but there were considerable changes in hepatic metabolism as shown by measurements of the hepatic parenchymal pH, transhepatic oxygen consumption, and lactic acid use. Of these, the parenchymal pH seems to be the most sensitive indicator of metabolic events.

Molybdenum requirements in low-birth-weight infants receiving parenteral and enteral nutrition.

BACKGROUND: Molybdenum (Mo) is an essential trace element required by three enzymatic systems, yet there are no reports of Mo deficiency in infants. Low-birth-weight infants (LBW) might be at risk for Mo deficiency because they are born before adequate stores for Mo can be acquired, they have rapid growth requiring increased intakes, and they frequently receive supplemental parenteral nutrition (SPN) and total parenteral nutrition (TPN) unsupplemented with molybdenum. METHODS: To investigate Mo requirements of LBW infants (n = 16; birth weight, 1336+/-351 g; gestational age, 29.8+/-2.5 weeks; M+/-SD), the authors collected all feeds, urine, and feces prior to TPN (baseline, n = 16, collections = 16), during TPN (n = 9, collections = 19), during SPN (n = 13, collections = 17), and after one week of full oral feeds (FOFs) of formula or human milk (FOF, n = 16, collections = 16). RESULTS: Infant weights at collection times were: 1.3+/-0.3 g, 1.27+/-0.4 g, 1.4+/-0.3 g, and 1.7+/-0.5 g, respectively. Mo intake was 0.03+/-0.1 microg/d, 0.34+/-0.1 microg/d, 1.25+/-1.7 microg/d, and 6.1+/-2.5 microg/d. Mo output was 0.64+/-0.6, 0.34+/-0.5, 0.68+/-0.8, and 4.1+/-2.5 microg/d. Mo balance at these times was -0.60+/-0.5, -0.001+/-0.5, 0.57+/-1.9, and 2.0+/-2.9 microg/d. Mo balance increased with time, yet some infants were always in negative balance, even though Mo intakes exceeded recommendations. CONCLUSIONS: The authors speculate that an intravenous intake of 1 microg/kg/d (10 nmol/kg/d) and an oral intake of 4-6 microg/kg/d (40-60 nmol/kg/d) would be adequate for the LBW infant.

Critical stenoses of the left anterior descending artery: predominant role in stress-induced pulmonary uptake of 201thallium.

OBJECTIVE: To relate the diagnostic finding of stress-induced pulmonary uptake of 201thallium to the severity and site of stenoses in specific coronary arteries. DESIGN: An ad hoc series of 525 referred cases had planar myocardial perfusion scintigraphy studies within four months of correlating invasive studies; patients who had previous revascularization procedures were excluded. MEASUREMENTS: Invasive studies were read by a cardiovascular radiologist with rating of stenoses as percentage luminal diameter, and grading of ventricular function from 1 (normal) to 5 (globally hypokinetic). Lung:myocardial ratios were quantitated independently on immediate poststress 201thallium myocardial perfusion images by a nuclear medicine physician. Multivariate regression equations were used to relate pulmonary uptake to stenoses in specific arteries and to the degree of ventricular dysfunction. RESULTS: Lung:myocardial ratios showed only a minor relationship to the number of subcritical (less than 90%) stenoses, but were considerably increased when severe (at least 90%) stenoses were present. Severe stenoses in the left anterior descending artery (LAD), particularly its proximal portion, provided the most dramatic increase in this index, modified by the contrast ventriculography score and to a lesser extent by additional stenoses at other sites. Regression analysis suggested a weighting of lesions in the LAD or left mainstem by a factor of at least 3 in comparison with the right coronary and left circumflex arteries. CONCLUSIONS: Stenoses in the LAD, particularly its proximal position, play a key role in the induction of increased pulmonary uptake of 201thallium on poststress scintigrams.

Ischemic left ventricular dysfunction assessed on ECG-gated thallium-201 myocardial perfusion images.

Ischemic dysfunction of the left ventricle can be suggested by ancillary data derived from thallium-201 myocardial perfusion images. In this study, qualitative and quantitative assessments of global and segmental contraction derived from ECG-gated left anterior oblique images were analyzed to define more precisely transient ischemic hypokinesis. Immediate (4 mins post stress) and delayed (2 to 4 h) images were compared in 200 patients; 165 had coronary angiography and 35 had a low probability of coronary artery disease based on pretest and test outcome variables. For both immediate and delayed images, a quantitative index of left ventricular contraction (derived from the time-activity curve of the left ventricular cavity and validated in a previous study), correlated well with contrast ventriculography scores. The index derived from the immediate image also was related to the severity/extent of coronary artery lesions and to thallium-201 lung uptake. The ratio of indices (immediate/delayed) was depressed (P less than 0.001) in patients with two or three critically diseased vessels, and reflected the qualitative assessment of stress-induced dysfunction on cinematic images. These data suggest that the quantitative index derived from ECG-gated perfusion scans may be a valuable indicator of stress-induced ventricular contractile dysfunction.

Myocardial uptake and washout kinetics of T1-201 with the VEX (vasodilator plus exercise) test: contribution of stress mode components and coronary stenosis severity.

OBJECTIVE: To assess the vasodilator plus exercise (VEX) test as an adjunct to myocardial perfusion imaging with respect to the accuracy of kinetics of thallium-201 (Tl-201) and other indicators of ischemia. SETTING: A nuclear medicine laboratory in which patients referred for myocardial scintigraphy are triaged to undergo the stress component with symptom-limited bicycle exercise, dipyridamole or VEX as appropriate. DESIGN: Cases having correlating scintigraphy and angiography (n = 425) were selected retrospectively. Immediate poststress and redistribution images were quantified using a circumferential profile analysis with interpolative background subtraction. For each of nine sectors on the left anterior oblique image, multivariate analyses were performed, comparing the relative uptake and net washout of Tl-201 to the exercise workload attained, use of dipyridamole, time to redistribution, gender, and the angiographic presence and severity of stenoses at five key sites. Washout values standardized according to gender, exercise level and time to redistribution, were compared with relative uptake profiles and ST depression using receiver operating curves. RESULTS: For each sector, a significant contribution to Tl-201 washout was made by the exercise level (P < 0.001) and by at least one site of stenosis (P < 0.0001), but not by use of dipyridamole (P > 0.5); female gender was associated with increased washout (P < 0.01) except for the three lateral sectors. For each stress modality, standardized washout performed better than ST depression but not as well as relative uptake profiles in detecting coronary artery disease. CONCLUSIONS: For combined pharmacological-exercise stress, quantitative uptake profiles may assist in confirming subjective scan interpretation; washout profiles, even when standardized for gender and stress level, are suboptimal for confirming defect reversibility.

Estimation of left ventricular function on ECG-gated thallium-201 myocardial perfusion images.

ECG-gated thallium-201 perfusion images (GT) may provide information concerning left ventricular contraction. To assess the objectivity of this information, qualitative and quantitative evaluations of left anterior oblique GT images were performed in 600 patients and compared with contrast ventriculography (n = 180) and gated blood pool scintigraphy (n = 60). Cinematic playback of GT allowed qualitative rating of ventricular performance in 98% of studies. Abnormal GT (focal or global hypokinesis) was found in 41% of cases and could be related to myocardial infarction, nonischemic cardiomyopathy or left bundle branch block. Blinded readings showed reasonable interobserver agreement and correlation with blood pool scintigraphy regarding segmental and overall left ventricular function; decreased tracer uptake in an abnormally perfused segment presented only occasional difficulty. A quantitative index was derived by relating the increment in left ventricular cavity activity during contraction to myocardial count density; results were expressed as a planar ejection fraction (PEF). PEF correlated well with ejection fraction on blood pool scintigraphy (r = 0.83, P less than 0.001) and with contractility scores derived from ventriculography (P less than 0.001) and seemed suited for identification of hypokinetic ventricles. Thus, GT allows objective estimation of left ventricular function as an addendum to myocardial perfusion imaging.

Markers of left ventricular dysfunction induced by exercise, dipyridamole or combined stress on ECG-gated myocardial perfusion scans.

An index of left ventricular contraction can be extracted from the cavitary time-activity curve of electrocardiographic (ECG)-gated myocardial perfusion scans. To assess the induction of stress-induced myocardial depression, we compared contraction indexes derived from immediate poststress and delayed 201Tl images with indexes of ventricular dilation and lung uptake in the prediction of severe coronary artery disease (defined as two or more 90% stenoses). Stress procedures were performed in 93 patients with symptom-limited supine bicycle exercise alone, and in 227 with intravenous dipyridamole, combined where possible with exercise. The immediate and delayed contraction indexes reflected left ventricular dysfunction on ventriculography (P < 0.0001), but additionally the immediate index was reduced (P < 0.0001) in severe coronary disease. Stress-induced hypokinesis was seen frequently after each of the test modes. The relationship with angiographic findings was better defined for indexes of contraction than for lung uptake or ventricular dilation (P < 0.01). The prediction of severe coronary disease was optimized by combining the poststress contraction index and lung uptake. These data support the use of ECG-gated myocardial scans in evaluating the functional consequences of stress/imaging procedures.

The usefulness of stress tests performed in the nuclear medicine department: mathematical methods to assess efficacy at various angiographic endpoints.

Stress myocardial perfusion scintigraphy (SMPS) may be used to amplify or supplant information available from stress electrocardiography (ECG) in directing the clinical management of patients, including the need for coronary angiography. The apparent usefulness of SMPS may depend on referral bias, the stress mode employed and the criterion for disease. We compared markers of ischaemia on quantitative planar SMPS with 201 Tl in 503 referred patients; stress was tailored to the individual patient to include exercise (n = 154), dipyridamole (n = 118) or a combination of the two (n = 231). Four angiographic criteria of increasing severity (A-D) were targeted. The fraction of the population receiving diagnostic benefit was calculated for reversible defects (RD) or lung uptake (LU) in comparison to concurrent ST depression; abnormal baseline tracings and fixed 201Tl defects were regarded as indeterminate. Decision tree induction, a computer-learning algorithm and logistic regression were also used to assess the contribution of 13 scintigraphic and other input variables. In comparison to ST depression, RD showed incremental value in 167 (33%) patients with criterion A, decreasing to 5% with criterion D; LU showed its greatest benefit (21%) with criterion D. Both scintigraphic markers were more useful with dipyrida-mole-based tests than with exercise alone. Decision trees induced at each criterion for disease showed the predominant contribution of scintigraphic results in comparison to clinical and ECG data. In conclusion, in a referred population with a frequent requirement for pharmacological stress, the clinical utility of scintigraphy can be determined by comparison of markers of ischaemia; the results will depend, however on the angiographic criterion for disease.

Seasonal variations in hair zinc concentrations in Canadian and African children.

Proximal occipital scalp hair samples were collected during three survey periods from 30 omniverous Canadian boys aged 75.6 +/- 10.4 months (mean +/- SD) and 66 rural Malawian children (37 M; 29 F) aged 62 +/- 10 months (mean +/- SD) consuming predominantly plant-based diets. Hair samples were washed and then analyzed for zinc and copper using instrumental neutron activation analysis. Selected anthropometric measurements were also taken and dietary intakes calculated from weighed dietary records. A marked seasonal variation in hair zinc concentrations occurred in both groups; levels were highest in the season with shortest daylight hours (i.e. December/January in Canada vs July/August in Malawi). A similar trend was not observed for hair copper concentrations. Changes in hair zinc were not associated with changes in growth indices, age, socio-economic group, method of infant feeding, in either group, but were related to intakes of protein (per 1000 kcal) (p = 0.02, r = -0.36), zinc (mg day-1) (p = 0.01, r = -0.39), and dietary fiber (g day-1) (p = 0.04, r = 0.28), in the Malawian children during the second survey period. The seasonal effect on hair zinc concentrations must always be considered when interpreting hair zinc concentrations in children; its etiology remains unclear.

Differential glomerular filtration rate in diagnosis of renovascular hypertension and follow-up of balloon angioplasty.

Two hundred nine hypertensive patients with high stimulated plasma renin levels were screened for renovascular hypertension using Tc-99m DTPA renal scintigraphy. Differential glomerular filtration rate (Diff-GFR) was obtained by integrating the area under the background-subtracted renogram of each kidney between 1 and 3 minutes. 50 patients who also had undergone selective renal angiography were divided into four groups according to Diff-GFR contribution by one of the kidneys. If one kidney contributed 45-50% of total GFR, this was regarded as normal. A Diff-GFR of less than 45% was very considered to be very suggestive of renovascular hypertension in the appropriate clinical setting, while a Diff-GFR of less than 20% indicated that the renal artery might not be amenable to successful balloon angioplasty. Diff-GFR following balloon angioplasty closely reflected the early clinical response of the patients--and in some cases progressive Diff-GFR improvement was observed several months later. Diff-GFR as a scintigraphic criterion for renovascular hypertension has a sensitivity of 93%, specificity of 74%, and accuracy of 85%.

Use of 5 French catheters for cardiac catheterization and coronary angiography: a critical review.

With the number of outpatient cardiac catheterizations increasing, much attention has recently been focused on the use of 5 French catheters for cardiac catheterization and selective coronary angiography. However, there are few reports in the literature regarding the technical aspects of their use or the quality of cineangiograms obtained. We reviewed our experience with these catheters in our first 100 consecutive cases. All cineangiograms were diagnostic, though 9% were deemed only of fair quality (incomplete luminal filling in some frames) by two experienced observers. Technical problems encountered with the use of these catheters included instability of the right Judkin's catheter in the right coronary ostium owing to high torquability, streaming of contrast during left coronary injections, and difficulty entering the left ventricle with a pig-tail catheter.