Dimercaptosuccinic acid scintigraphy vs. ultrasound for renal parenchymal defects in children.

INTRODUCTION: Dimercaptosuccinic acid (DMSA) scintigraphy is the gold standard in the evaluation of renal parenchymal defects and is widely used in the pediatric population. As more recent ultrasound equipment was purchased at our tertiary pediatric centre, our objective was to evaluate if renal ultrasound (US) results are equivalent or sufficient when compared to DMSA scintigraphy in the assessment of renal anomalies. METHODS: The charts of all 463 patients who underwent DMSA scintigraphy between January 2009 and May 2014 at our pediatric tertiary centre were reviewed. The objective was to look for correlation between US and DMSA scan results for renal scars/dysplasia. A hundred and sixty pediatric patients followed with US and DMSA scan for a total of 285 renal units remained for evaluation after exclusions. Timing of the exams, urinary tract infection (UTI), and indication for imaging were reviewed. Results with older (105 patients) and newer (55 patients) US equipment were compared. RESULTS: Among the 285 renal units evaluated, 39 (14%) had renal parenchymal defects shown by US and 87 (31%) by DMSA scintigraphy (sensitivity 36%, specificity 96%). The DMSA scan was normal for eight abnormal kidneys (3%) on US. The results were not statistically significant when compared to exams performed with newer or older US machines. CONCLUSIONS: At our institution, US data are not sensitive enough to give reliable information about renal parenchymal defects, even with newer equipment. DMSA scintigraphy still remains mandatory for the evaluation of renal anomalies, but could be optional if the US exam indicates parenchymal defects.

Identifying which treated hypertensive patients without known coronary artery disease should be tested for the presence of myocardial ischemia by perfusion imaging.

Stress dipyridamole technetium-99(m) sestamibi single photon emission computed tomographic imaging was used to study myocardial perfusion in 1116 hypertensive patients without known coronary artery disease (CAD). The test confirmed the presence of CAD in 28.9% of patients. As expected, patients with diabetes mellitus (DM) had a significantly higher prevalence of myocardial perfusion abnormalities (35.9% vs 23.9%; odds ratio, 1.79; 95% confidence interval [CI], 1.38-2.33; P<.0001) and high-risk myocardial imaging (16.4% vs 10.6%; odds ratio, 1.67; 95% CI, 1.18-2.37; P=.004) than those without DM. Odd ratios further increased, again as expected, with dyslipidemia (2.19; 95% CI, 1.54-3.12; P<.0001), peripheral arterial disease (2.61; 95% CI, 1.77-3.85; P<.0001), microalbuminuria (3.03; 95% CI, 1.91-4.82; P<.0001), and abnormal electrocardiographic findings (3.06; 1.68; 95% CI, 2.08-4.48; P<.0001). This large cohort study showed that more than 1 of 4 treated hypertensive patients have subclinical CAD. These study data should be clinically helpful in selecting hypertensive patients who are the most suitable candidates to screen for the presence of CAD.

Noninvasive detection of silent coronary artery disease in patients with essential hypertension, alone or associated with type 2 diabetes mellitus, using dipyridamole stress 99mtechnetium-sestamibi myocardial perfusion imaging.

BACKGROUND: Coronary artery disease (CAD) is the leading cause of morbidity and mortality in hypertensive and diabetic patients. Early diagnosis of CAD and identification of high-risk subgroups, followed by appropriate therapy, may therefore enhance survival. OBJECTIVES: To prospectively establish the prevalence of silent CAD in asymptomatic patients with essential hypertension (EH), and to establish to what extent type 2 diabetes mellitus (DM) modifies the prevalence and severity of silent CAD in these patients. METHODS: The study population consisted of 543 patients 45 years of age and older with EH (n=321) or EH with type 2 DM (n=222), without typical angina or known CAD, selected according to criteria defined by the American Diabetes Association. All patients underwent dipyridamole stress and rest 99mtechnetium sestamibi myocardial single-photon emission computed tomography imaging. The stress and rest myocardial images were divided into 20 segments and blindly scored by two experienced observers. The summed stress score and summed rest score were obtained by adding the scores of the 20 segments of the stress and rest sestamibi images, respectively. The difference between the summed stress score and the summed rest score was defined as the summed difference score, representing reversible ischemia. RESULTS: There was a significant difference (P=0.001) between the percentage of EH patients with (41.4%) and without (27.7%) DM, with regard to abnormal summed stress scores. Moreover, hypertensive, diabetic patients had a significantly greater incidence of moderate to severe ischemia (P=0.011). In addition, a significantly greater proportion of hypertensive patients with DM showed reversible ischemia compared with EH patients without DM (39.6% versus 24.6%; P<0.0001). Proteinuria and dyspnea were significant predictors of silent ischemia in EH patients with DM. CONCLUSIONS: In this high-risk population screened according to the American Diabetes Association criteria with dipyridamole sestamibi myocardial single-photon emission computed tomography imaging, the prevalence of silent ischemia was 28% in EH patients. It is noteworthy that the prevalence (41%) and severity of silent ischemia were significantly greater in EH patients with DM.

Real-time imaging of myoblast transplantation using the human sodium iodide symporter.

The quantification of the graft success is a key element to evaluate the efficiency of cellular therapies for several pathologies such as Duchenne muscular dystrophy. This study describes an approach to evaluate the success of myoblast transplantation (i.e., survival of the transplanted cells and the muscle fibers formed) by real-time imaging. C2C12 myoblasts were first transfected with a plasmid containing the human sodium iodide symporter (hNIS) gene. Specific uptake of the radioactive sodium pertechnetate (Na99mTcO4) by the hNIS-positive myoblasts was demonstrated in vitro, while only background level of Na99mTcO4 was observed within the control cells. The cells were then transplanted into the tibialis anterior (TA) muscle of mdx (X-linked dystrophic) mice. Following intraperitoneal administration of Na99mTcO4, scintigraphies were performed to detect hNIS-dependent Na99mTcO4 uptake within the TA. This approach permitted to evaluate the progression of the transplantation and the graft success without having to biopsy the animals during the follow-up period.

Magnetic resonance-guided percutaneous cryosurgery of breast carcinoma: technique and early clinical results.

PURPOSE: This phase I study was designed to demonstrate the feasibility, safety, efficacy and predictability of percutaneous cryosurgery, guided under magnetic resonance (MR) imaging, in the treatment of invasive breast carcinoma. PATIENTS AND METHODS: Under the guidance of near-real-time T1-weighted FSE images of a 0.5-T open-configuration MR system, percutaneous cryosurgery was performed in 25 patients with operable invasive breast carcinoma, 4 weeks prior to their scheduled mastectomy. Predictive assessments by interventional radiologists using 4 breast-imaging techniques (mammography, sonography, scintigraphy and MR) were correlated with postmastectomy results of histopathology and assessed for predictability. Local and systemic morbidity were also evaluated during the month of follow-up preceding mastectomy. RESULTS: Percutaneous cryosurgery resulted in no serious complications, either local or systemic. All tumoural tissues included in the cryogenic "iceball" were destroyed, with no viable histologic residues. Ablation was total in 13 of the 25 tumours treated. Combining periprocedural MR images with postprocedure scintimammographic findings enabled a 96% rate for predicting the cryosurgical results. CONCLUSIONS: MR-guided cryosurgery of breast carcinoma is feasible, safe and efficient, with predictable results. Major drawbacks are that the cryolesion (a palpable iceball) persists for a month or more after the procedure, undermining the reliability of the physical examination; and that breast imaging (mammography, ultrasound and MR) presents the same difficulty of interpretation as the physical exam even 1 month after the procedure. More studies are required to refine this treatment method.

The clinical meaning of gastric-wall hyperactivity observed on sestamibi cardiac single-photon emission computed tomography.

OBJECTIVE: To evaluate prospectively the incidence and clinical meaning, if any, of gastric-wall hyperactivity observed on sestamibi cardiac single-photon emission computed tomography (SPECT). This phenomenon is completely different from the well-known intraluminal gastric reflux of sestamibi. METHODS: A group of 819 patients who underwent sestamibi cardiac SPECT was studied from January 2000 to October 2000. Gastric-wall activity was graded qualitatively. Only patients with gastric-wall activity near or equivalent to their heart activity were considered for subsequent analysis. The medical records of patient candidates were reviewed, and their family physicians were asked to respond to a questionnaire by telephone when further information was needed. RESULTS: We identified 13 patients with significant gastric-wall hyperactivity, which was more intense on rest images. Our review of the clinical data shows that all these patients were suffering from dyspepsia and were taking gastric medication. These 13 cases were assigned to 3 groups: gastroesophageal reflux, chronic functional dyspepsia and nonspecific gastritis. Significant gastric-wall hyperactivity is an infrequent observation on sestamibi cardiac SPECT. Our results indicate that the presence of significant gastric-wall hyperactivity is associated with dyspepsia. CONCLUSION: It is important to realize that this gastric-wall hyperactivity by its proximity to the inferior myocardial wall could in some circumstances lead to either false-negative or false-positive findings, representing a diagnostic problem. Although infrequent, this situation could be avoided by proper quality control, including a systematic review of the raw cine data before reading the images.

Early transient hydronephrosis after laparoscopic aortobifemoral bypass grafting.

Hydronephrosis early after aorto-bifemoral bypass grafting is probably an underestimated complication. We describe early and transient hydronephrosis that developed in two patients after totally laparoscopic aorto-bifemoral bypass surgery to treat aortoiliac occlusive disease. A conservative approach to treatment was adopted, and both patients recovered. We review the literature and discuss the pathophysiology, diagnosis, and treatment of this unusual form of hydronephrosis.

Does bone change after biliopancreatic diversion?

This prospective study evaluated bone changes after biliopancreatic diversion (BPD) consisting of a distal gastrectomy, a 250 cm alimentary channel, and a 50 cm common channel. Thirty-three consecutive patients had clinical, biochemical, and bone mineral density analysis before surgery and 4 and 10 years after surgery. Iliac crest bone biopsies and special tests including parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25-OH(2)-D), bone-specific alkaline phosphatase (BAP), and osteocalcin were obtained at surgery and 4 years postoperatively. Over the years, with close metabolic surveillance, additional calcium and vitamin D were given as indicated. After BPD, serum levels of calcium and vitamin D were decreased and serum levels of PTH, BAP, and osteocalcin were increased. Bone turnover and mineralization were both increased. Mean osteoid volume (P < 0.0007) and bone formation rate in relation to bone volume (P < 0.02) were increased. Static measures of bone were altered as follows: cortical thickness decreased (P < 0.01) and trabecular bone volume increased (P < 0.01). Ten years after surgery, overall bone mineral density was unchanged at the hip and was decreased by 4% at the lumbar spine. Overall fracture risk, based on the Z score, was unchanged. Preoperative factors predicting bone loss included menopause, smoking, and preexisting osteopenia. An elevated level of 1,25-OH(2)-D was also found to be a predictor of future bone loss (r = 0.40; P < 0.002). After surgery, a greater increase in bone markers and bone turnover was associated with an increased risk of bone loss. Although elevated osteocalcin levels were associated with overall bone loss (r = 0.52; P < 0.002), lower albumin levels were associated only with bone loss at hip level (r = 0.44; P < 0.02), whereas lower calcium levels were associated only with the loss at the lumbar spine (r = 0.39; P < 0.02). Ten years after surgery, bone loss at the hip continued to depend on albumin levels (r = 0.37; P < 0.03). We concluded that bone was relatively tolerant to the metabolic changes due to BPD. Provided that there is close surveillance for metabolic disturbances, the use of appropriate supplements, and the avoidance of malnutrition, the beneficial effects of surgery far outweigh the risk of postoperative bone disease.

Association of physical activity and bone: influence of vitamin D receptor genotype.

PURPOSE: The aim of the study was to investigate the interaction between leisure physical activity and a BsmI polymorphism at the vitamin D receptor (VDR) gene on the modulation of bone mineral density (BMD). METHODS: We studied 575 unrelated healthy postmenopausal women. Lumbar spine and femoral neck BMD were measured by dual-energy x-ray absorptiometry (DXA), and results were expressed as age-and-weight-adjusted (Z-score). VDR BsmI genotype was determined by polymerase reaction chain on peripheral blood leukocytes. RESULTS: Overall, no significant association was found between the level of leisure physical activity or VDR genotypes and adjusted BMD at both bone sites. However, in active women, there was a trend for an association between VDR genotypes and adjusted BMD at the lumbar spine. Active women, who exercised three times or more a week, carrying the "bb" genotype had a lower BMD at the lumbar spine than active women carrying "BB" genotype (ANOVA; P = 0.04). No significant difference in crude or adjusted BMD at both bone sites was found between VDR genotypes in sedentary or moderately active women. Furthermore, classification of women according to the median-age of the sample (63.1 yr) revealed a significant interaction between the level of leisure physical activity and VDR genotype on adjusted lumbar spine BMD in the older active postmenopausal women (N = 137). Older active women carrying the "bb" genotype showed a lower adjusted BMD at the lumbar spine compared with active women carrying the "BB" genotype (P = 0.007). CONCLUSION: These results suggested that gene-environment interactions such as leisure physical activity and VDR genotype may play a role in maintaining the BMD at the lumbar spine in active postmenopausal women, especially in older active women.