-
[show abstract]
[hide abstract]
ABSTRACT: The significant potential for perioperative and late cardiovascular complications makes careful preoperative cardiac risk assessment imperative in liver transplantation candidates.
To determine the sensitivity and specificity of myocardial perfusion scanning for detection of coronary artery disease (CAD) in liver transplantation candidates.
We prospectively evaluated 93 liver transplantation candidates. Patients with known CAD were excluded. All patients, regardless of symptoms and risk factors, underwent myocardial perfusion scanning and coronary angiography.
Results of myocardial perfusion scanning were abnormal in 64 patients (68.8%) and normal in 29 patients (31.2%). Of patients with abnormal scans, only 6 (9.4%) had severe CAD at coronary angiography. None of the 29 patients with normal perfusion scans and the 24 patients with fixed defects had severe CAD; however, 6 of 40 patients (15.0%) with reversible perfusion defects had severe CAD at coronary angiography (P = .005). Alcoholic liver disease, reversible perfusion defects at myocardial perfusion scanning, left ventricular systolic dysfunction, and higher low-density lipoprotein (LDL) cholesterol and triglyceride levels were significantly associated with CAD. Defining reversible perfusion defects as a sign of ischemia, and fixed defects and normal perfusion as nonischemic, myocardial perfusion scanning had 100% sensitivity but 61% specificity for severe CAD. The test's accuracy was low (38%).
The results of reversible perfusion defects on myocardial perfusion scanning were sensitive but not specific for CAD in liver transplantation candidates. The high number of false-positive results decreased the test's accuracy.
Transplantation Proceedings 11/2009; 41(9):3757-60. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The perfusion time-activity curve on DTPA renal scintigraphy shows a peak and plateau pattern which is usually absent or less marked when using tubular agents such as MAG3. The exact mechanism that results in this difference between the two tracers is not well understood. A descending pattern on MAG3 has been proposed to be due to decreased extraction. In this study we compared the diagnostic utility of perfusion patterns obtained with DTPA and MAG3 among patients with renal allograft dysfunction.
This study included 48 patients with renal allograft dysfunction and 18 recipients with normal graft function. Every recipient had renal scintigraphy with Tc-99m MAG3 and Tc-99m DTPA 1 day apart. The second phase of the perfusion curve after the initial rise was classified as ascending, flat, or descending. In patients with a descending curve on DTPA study, we calculated the ratio of counts at peak perfusion to that at plateau (P:PL). Impaired perfusion was based on a deterioration of the peak-to-plateau pattern on DTPA and the presence of a flat-descending curve on MAG3.
In patients with dysfunction, impaired perfusion was observed in 77% of DTPA and in 54% of MAG3 studies. A flat-descending curve on MAG3 was present in 44% of patients with normal graft function. By MAG3, 67% of acute rejection and 28% of chronic allograft nephropathy (CAN) cases showed deteriorated perfusion. The corresponding values for DTPA were 67% and 94%, respectively. A flat-ascending pattern on DTPA was more frequent in CAN than it was in acute rejection (33% and 17%, respectively).
The sensitivity of DTPA perfusion pattern for diagnosing dysfunction was significantly greater than that for MAG3. Our results suggest that the major determinant of a curve pattern on DTPA or MAG3 study is the extraction relative to perfusion. Thus for patients with CAN, extraction is higher relative to perfusion, resulting in a lower P:PL ratio or an ascending curve on DTPA. Although the extraction of DTPA is less than that of MAG3, this level of extraction renders DTPA more sensitive to serial changes in renal function and pathophysiological mechanisms related to kidney function.
Transplantation Proceedings 04/2006; 38(2):449-53. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Specific criteria for diagnosing an acute rejection episode (ARE) are not present on renal scintigraphy. However, a deterioration in renal function observed on serial imaging is suggestive of an ARE during the early posttransplantation period. In this study, we evaluated Tc-99m DTPA renal scintigraphy findings among patients with renal allograft dysfunction. The aim was to define criteria for ARE on a single imaging study alone.
This study included 82 patients with renal allograft dysfunction, each of whom had a specific biopsy-proven pathology. From the background-corrected Tc-99m DTPA renal time-activity curves, the following parameters were computed: the ratio of counts at peak perfusion to that at plateau (P:PL) and the ratio of counts at peak perfusion to that at peak uptake (P:U). The images were inspected visually for excretion patterns and other morphological changes.
A specific renogram pattern, that is an increase in perfusion to uptake ratio together with a nearly flat uptake curve and preserved peak/plateau pattern, was observed in 67% of low-grade AREs. In contrast, a flat uptake curve usually occurred together with a loss of peak/plateau pattern in a high-grade ARE. The findings that were highly specific for ARE on visual inspection were little or no collecting system activity, pelvic hypoactivity, and indistinctness of the corticomedullary junction.
Our results indicate that in low-grade ARE, there is decreased filtration relative to perfusion as evidenced by a decrease in the perfusion-to-uptake ratio with loss of a peak/plateau pattern. A hypoactive pelvis with little activity in the collecting systems may be due to edema in the renal interstitium and pelvicalyceal structures.
Transplantation Proceedings 04/2006; 38(2):443-8. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Various parameters can be derived from a renogram, but the relationship between uptake and perfusion pattern on Tc-99m DTPA time-activity curves has not been evaluated to date. A previous report documented sequential changes in the relationship between perfusion and uptake in renal transplant donors. The current study looked at serial changes in renogram patterns in kidneys exhibiting hyperfiltration. The aim was to reveal the pathophysiological significance of different perfusion-uptake patterns observed on Tc-99m DTPA renal scintigraphy.
Serial changes in two patient groups were evaluated: (A) renal transplant donors before, early after, and late after donor nephrectomy; and (B) renal transplant recipients at the initial and later stages of chronic allograft nephropathy (CAN). Quantitative scintigraphic parameters included: the ratio of peak perfusion counts to plateau counts (P:PL); the ratio of counts at peak perfusion to counts at peak uptake (P:U); and the glomerular filtration rate. The effect of background selection on the parameters, P:PL and P:U, was evaluated using three different background regions of interest.
Each group in the study exhibited a different renogram pattern. Based on these results, renograms were classified into six patterns. Compared to the preoperative findings, P:U and P:PL increased significantly early after the operation. Late after the operation, P:U decreased significantly compared to both pre- and early postoperative values. In patients at the early stages of CAN, both P:PL and P:U were lower than normal. During the later stages of CAN, perfusion and uptake peaks were absent.
Our results identified several different renogram patterns that were thought to correspond with hyperperfusion, hyperfiltration, increased intraglomerular pressure, and glomerulosclerosis. The ratios of P:PL and P:U underwent significant change under conditions that affected kidney hemodynamics and function.
Transplantation Proceedings 01/2006; 37(10):4259-65. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Chronic allograft nephropathy (CAN) is usually progressive; its natural course can only be modified in the initial stages. In this study, we graded Tc-99m diethylenetriaminepentaacetic acid (DTPA) renogram curves with respect to the perfusion/uptake pattern and correlated these findings with biopsy results in patients with CAN.
This study included 63 renal allograft recipients with biopsy-proven CAN. The agent used for renal scintigraphy was Tc-99m DTPA. Quantitative evaluation of perfusion included calculation of the ratio of peak perfusion counts divided by plateau counts (P:PL). Deterioration of renal function was accompanied with a gradual loss of a peak and plateau pattern. For the evaluation of uptake in relation to perfusion pattern, we graded the renogram curves into four based on the presence of a peak and plateau pattern and the presence of an uptake peak.
In patients with CAN, the mean P:PL was significantly lower than that of the control group. The serial changes in successive grades of CAN in respect to uptake-perfusion pattern was a gradual loss of peak and plateau pattern followed by a decline in uptake. In recipients with high-grade CAN, an uptake peak was absent.
Evaluation of Tc-99m DTPA time-activity curves revealed a progressive change in perfusion-uptake pattern in patients with CAN. According to our results, deterioration of perfusion preceded the decline in uptake. Serial renogram changes are thought to reflect initial hypoperfusion followed by increased intraglomerular pressure and finally glomerulosclerosis. These findings have implications for the pathophysiology and management of CAN.
Transplantation Proceedings 10/2005; 37(7):3124-9. · 1.00 Impact Factor
-
Transplantation Proceedings 09/2001; 33(5):2858-9. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We attempted to ascertain the impact of Co-60 conventional external radiotherapy (cRT) on the perfusion of normal brain tissue in relation to the radiation doses delivered to the tumors in patients with primary brain tumors.
After surgery 18 patients (pts) were due to undergo cRT with a total dose of 5400- 6400 cGy. All the patients had a Tc-99m-HMPAO SPECT study prior to cRT (basal), 15th and 30th days of cRT as well as 1 (in 6 pts), 3 (in 9 pts), and 6 (in 3 pts) months after cRT. For quantitative evaluation, the entire set of transverse slices were divided into 4 regions as frontal, parietal, occipital and temporal regions by means of a computer software program. Semi-automated quantification was performed on a total of 1392 regions in 87 studies to determine left to right ratios. An interregional difference of at least 10% was considered abnormal.
After elimination of tumor sites, 80 normal brain regions showed decreased perfusion after cRT. The percent decrease in perfusion was (mean 22.5+/-9.9) significantly higher in areas irradiated with doses > 3000 cGy (p < 0.05).
cRT has adverse effects on the perfusion of normal brain tissue for doses > 500 cGy. Our findings justify treating patients with small and limited lesions with stereotactic radiotherapy in order to minimize the adverse effects of cRT on normal tissues.
Annals of Nuclear Medicine 02/2000; 14(1):17-23. · 1.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this study, we evaluated the relationship between the degree of gastro-oesophageal reflux and the rate of gastric emptying and determined the variability of gastric emptying in children. The reproducibility of radionuclide imaging for the presence and grading of gastro-oesophageal reflux was also examined. Twenty-eight children less than 2 years of age participated in the study. For assessment of variability, all subjects underwent two scintigraphic studies. For each study, the number of reflux episodes and gastric emptying half-times were recorded. The amount of reflux was graded according to the classification suggested by Blumhagen. Patients with grade 1 reflux were considered low-grade refluxers, while patients with grade 2 or 3 reflux were considered high-grade refluxers. The level of reflux for each patient was based on the highest reflux grade recorded in either study. Of the 28 patients, 19 had reflux in at least one study. Ten patients had high-grade and nine patients low-grade reflux. All patients but one with high-grade reflux had the same grade of reflux in both studies (90%). Of nine patients with low-grade reflux, three had the same grade in both studies. The mean half-time was significantly higher for high-grade than for low-grade refluxers (P < 0.05). For subjects with low-grade reflux, this value did not differ significantly from that of non-refluxers (P > 0.05). Our results show that patients with high-grade gastro-oesophageal reflux had prolonged gastric emptying. The inter- and intra-subject variability of gastric emptying in children appeared to be low. Reproducibility for the presence and grading of gastro-oesophageal reflux by the radionuclide method was good, with the highest value being for the diagnosis of high-grade gastro-oesophageal reflux.
Nuclear Medicine Communications 11/1999; 20(10):907-10. · 1.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Paranasal sinus infections and nasolacrimal duct obstructions are commonly encountered problems. However the relationship between these two conditions is not yet clear. Trauma, surgery, tumors, and systemic diseases are among the causes of acquired nasolacrimal duct obstructions but most of the cases are idiopathic. In this study patients diagnosed with chronic paranasal sinus infection were examined with 99mTc lacrimal dacryoscintigraphy to assess their nasolacrimal duct function.
Twenty-four patients diagnosed with chronic paranasal sinus infection are included in the study. These patients were observed for at least three months awaiting surgical treatment following unsuccessful medical treatment. The control group included 16 persons admitted to the ophthalmology department without any nasolacrimal duct disease. Nasal endoscopy and paranasal sinus CT revealed normal findings. The age of the patients with chronic paranasal sinus infection and examined in regard to nasolacrimal duct function was between 15 to 17 with a mean age of 34.2 years. Fourteen patients were male and 10 patients were female. The control group included 9 male and 7 female patients between 18 to 60 years with a mean of 30.5 years.
The dacryoscintigraphic examination of 48 nasolacrimal ducts in 24 patients with chronic paranasal sinus infection revealed 7 complete and 18 partial obstructions of the duct, and 23 normal findings. In the control group with 32 nasolacrimal ducts of 16 patients, there was no complete obstruction. Partial obstruction (10.6, 12.0, 14.7 minutes) was be observed in three cases. The statistical workup resulted in a significant difference between paranasal sinus patients and control group (x2 = 15,840 p < 0.001). The paranasal sinus CTs of the patients with paranasal sinus disease were staged using the Lund-Mackay staging system: There is no correlation between the staging score of the paranasal sinus infection and the degree of the obstruction the nasolacrimal duct.
This study shows that chronic paranasal sinus disease plays an important role in the pathogenesis of nasolacrimal duct obstructions. The presence of infection has an influence on the nasolacrimal drainage system, but the distribution (staging) of the infection does not appear to correlate with the degree of nasolacrimal duct obstruction. Partial obstruction cases that may progress to complete obstruction may be detected by dacryoscintigraphy, and the treatment of chronic paranasal sinus disease may help to overcome the lacrimal drainage problems in these cases.
Laryngo-Rhino-Otologie 07/1999; 78(7):382-6. · 0.97 Impact Factor
-
Transplantation Proceedings 06/1998; 30(3):771-2. · 1.00 Impact Factor
-
Transplantation Proceedings 06/1998; 30(3):786-7. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Behçet's disease (BD) (OMIM 109650) is an immunogenetically based multisystem disease, characterized by iridocyclitis, arthritis, orogenital ulcerations and pustular skin lesions. Viral and autoimmune etiologies have been suggested and HLA-B5 has been found to predominate in BD. The disease is most seen in Turkey and Japan. Although familial cases have been reported, the mode of inheritance is not clear. To determine the genetic instability in BD, sister chromatid exchange (SCE) analysis has been performed on peripheral lymphocytes in 23 patients and 20 healthy controls. We found significantly higher SCE rates in the patient group (p < 0.0001). Our results may indicate that genetic impairment and genetic instability may play an important part in the etiology of BD.
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 02/1998; 397(2):235-8. · 2.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Glutathione labelled with 99mTc was used to study blood clearance and normal distribution in 3 healthy volunteers and in 10 patients with biopsy-proven tumors in the head and neck region. Static scintigrams were obtained at 1, 3, 6, and 24 h. ROIs over tumors and normal soft tissues were compared to obtain T/N ratios. In normal subjects blood clearance reached a plateau at 6 h; no radio-activity accumulation in the head and neck region was observed. Only the cardiac blood pool, the liver, the kidneys and the urinary bladder were evident. Excretion was via the kidneys. Malignant tumors and metastases were well visualized in 7 patients (true-positive), starting at 1 h. The mean T/N ratio was 2.69 +/- 0.77. The best images were obtained at 3-6 h. 1 false-positive (granulamatous reaction), 1 false-negative (malignant epithelial tumor in the radix of tongue) and 1 true-negative (angiofibroma) results were obtained. 99mTc-GSH is a potential radiopharmaceutical for the scintigraphic visualization of head and neck tumors. Further clinical studies are warranted to show its sensitivity and accuracy.
Nuklearmedizin 11/1994; 33(5):224-8. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The purpose of this study was to demonstrate the accumulation of 99Tcm-glutathione (GSH) in experimental abscesses. The biodistribution of 99Tcm-GSH was determined in mice with turpentine-induced abscesses in comparison with 99Tcm-human immunoglobulin (HIG) at 1, 3, 6 and 24 h. Arthritis was induced by intra-articular injection of ovalbumin in the right front knees of 16 rabbits. Each radiopharmaceutical (RP) was administered intravenously to eight rabbits. Scintigrams were obtained and regions of interest (ROIs) over the involved and contralateral knees were compared. Blood clearance of both RPs was studied in 10 normal rabbits. Biodistribution studies indicated accumulation of 99Tcm-GSH in abscesses. Abscess to liver, muscle, intestine and blood ratios were higher at all time points compared to 99Tcm-HIG. The maximum abscess:muscle ratios were 7.57 +/- 0.73 and 5.98 +/- 1.17 at 24 h for 99Tcm-GSH and 99Tcm-HIG, respectively. Scintigraphic images demonstrated both the abscesses and arthritic joints very well. 99Tcm-GSH is superior to 99Tcm-HIG due to clearance predominantly via kidneys, no significant accumulation in any other organs, high target-to-nontarget ratios attained a few hours after administration, low cost and in-house preparation by a simple procedure.
Nuclear Medicine Communications 08/1994; 15(7):533-9. · 1.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Radionuclide imaging is a valuable tool during the early posttransplantation period for evaluating the functional status of renal and liver allografts. The aim of this study was to compare the early postoperative function of renal and liver allografts with serial radionuclide imaging.
Twenty-two renal and 22 liver allograft recipients were evaluated with serial radionuclide imaging. All grafts were from living related donors. For renal scintigraphy, recipients were injected with Tc-99m DTPA, and imaging was performed on postoperative days 3 and 7. Liver allograft recipients were evaluated with Tc-99m mebrofenin hepatobiliary scintigraphy within the first postoperative week and as required thereafter. The following parameters were computed for each scintigraphy: uptake, time to excretion of the radiopharmaceutical (T(ex)), and retention of radioactivity at the end of the study.
Among 22 renal transplant recipients, 19 (86%) had normal uptake and T(ex) values on day 7 posttransplantation. Nine (41%) renal grafts exhibited retention. Among 22 liver transplant recipients, 7 (32%) had normal findings on the first hepatobiliary scan. All except eight liver grafts (64%) had a delay in T(ex), and 15 (68%) had parenchymal retention on the first scan, with improvement of function observed on serial scintigraphies obtained during follow-up. Decreases in uptake were seen less frequently and correlated with a prolonged postoperative hospital stay.
Renal transplant recipients are more likely than liver allograft recipients to have a normal scintigraphy in the early posttransplantation period. Retention of radioactivity at the end of the study was the most frequently observed abnormality for both renal and liver allografts. Most liver transplant recipients exhibited a delay in excretion, and parenchymal retention, of radioactivity on the first evaluation, with subsequent improvement on follow-up serial scintigraphy studies.
Transplantation Proceedings 37(1):355-8. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The measurement of intrarenal resistance indices (RIs) by doppler ultrasound plays an important role in the evaluation of renal transplant recipients. Although an elevated RI was initially considered to be specific for rejection, later studies revealed this parameter as a nonspecific marker of transplant dysfunction. In this study, we analysed Tc-99m DTPA renal scintigraphy findings in patients with increased RI during the early posttransplantation period.
This study included 22 patients with increased RI on doppler sonography during the first week after transplantation. Twenty-two recipients with uncomplicated early postoperative courses were used as a control group. An RI value >0.7 was considered pathologic. All patients underwent Tc-99m DTPA renal scintigraphy just after doppler sonography. In addition to visual interpretation of images, renogram curves were evaluated for patterns suggestive of acute tubular necrosis and acute rejection. Glomerular filtration rate (GFR) was calculated using computer software. Perfusion time-activity curves were assessed for the presence of peak and plateau patterns to calculate this ratio (P:PL).
The mean value for P:PL in patients with increased RI and in the control group were 1.37 +/- 0.33 and 1.53 +/- 0.47, respectively (P < .05). The mean value for GFR was significantly lower in the patient group compared with control subjects. Six patients had normal perfusion and function (27%). Perfusion pattern and renogram changes were suggestive of acute tubular necrosis in 5 patients and acute rejection in 6 patients. These diagnoses were confirmed later with serial scintigraphic changes or biopsy results. Three patients had an accumulation pattern on the renogram suggesting partial obstruction.
During the early posttransplantation period an increased RI on doppler sonography was seen in both normal functioning grafts and those with allograft dysfunction. Renal scintigraphy with perfusion and renogram patterns highly suggestive of specific allograft pathologies seemed to provide useful information to distinguish early postoperative renal allograft pathologies.
Transplantation Proceedings 40(1):100-3. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study compared hepatobiliary scintigraphy findings in livers before and after liver graft donation to examine whether there is a change in hepatobiliary dynamics. Nine donors underwent hepatobiliary scintigraphy with intravenous injection of Tc-99m mebrofenin 1 day before and during the first week after left liver lobectomy. Five donors also underwent additional scintigraphy more than 1 year postsurgery. Images were acquired every second for the first minute, and then every minute for the next 40 minutes. Hepatic arterial perfusion index and portal perfusion index(PPI) were calculated from the images acquired during the first minute. For the function phase the computed parameters included: hepatic extraction efficiency, (HEE), time to appearance of activity in the intrahepatic biliary channels, and in the intestine, time to half maximal activity, and activity retained in the liver parenchyma at 40 minutes. Time to appearance of intrahepatic biliary channels and of intestinal activity was shorter among scintigraphies obtained within 1 week postsurgery compared to the preoperative values. Early after the operation HEE increased and PPI decreased significantly. Visual inspection of the scintigraphy scan obtained in all donors, within the first week postsurgery revealed hypertrophy of the right liver lobe. None of the patients showed progression of right lobe activity to the left side, even among scans obtained more than 1 year after donation. Reduced time to activity in the biliary channels and intestine and increased HEE suggest acceleration of hepatobiliary dynamics.
Transplantation Proceedings 36(1):206-9. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Behçet's disease is a systemic vasculitis of unknown aetiology. Endothelial cell injury plays an important role in the pathogenesis and immunopathology of systemic vasculitises, but an immunopathogenic basis is also probable in Behçet's disease. E-selectin is an indicator of endothelial injury, and beta 2-microglobulin (beta 2M) is increased in immunological disorders. The serum concentrations of these two markers were determined in 40 patients with active Behçet's disease and 40 healthy controls. E-selectin was determined by enzyme-linked immunosorbent assay and beta 2M was determined by the nephelometric method. The mean (+/- SD) serum concentration of E-selectin was 122.13 +/- 62.32 ng/ml and that of beta 2M was 0.31 +/- 0.05 mg/dl. Both concentrations were statistically significantly increased in patients with Behçet's disease compared with controls. More comprehensive studies are needed to determine whether these parameters are useful indicators of the activity of Behçet's disease.
The Journal of international medical research 30(1):85-8. · 0.90 Impact Factor
