Gulgun Buyukdereli

Evaluation of vascularized graft reconstruction of the mandible with Tc-99m MDP bone scintigraphy

AimThe aim of this study was to evaluate the value of bone scintigraphy for the assessment of graft viability following vascularized bone grafts in patients with mandibular reconstruction.MethodsWe investigated 16 patients with vascularized grafts from the fibula (13 patients) and iliac crest (3 patients) in the last 8 years. For the follow up of all these patients, Tc-99m MDP bone scintigraphy was performed between 2-10 days postoperatively. SPECT study was included in 5 patients. For the evaluation of the grafts, a six-grade scoring system was used. The grading system was based on a comparison of tracer uptake between graft and the cranium. The uptake was defined as increasing from grade 6 to grade 1.ResultsThirteen of the 16 grafts had an uncomplicated clinical course. Complications in the graft occurred in three patients. In the analysis of planar scintigrams, patients with uncomplicated healing showed increased uptake in 12 of the 13 grafts (grade 1-3) and 1 showed the same level tracer uptake compared to cranium (grade 4). In the failed 3 grafts, decreased uptake was observed (grade 5 and 6). In 5 patients, SPECT was performed in addition to planar imaging. In these patients, 4 of the 5 grafts had an uncomplicated clinical course and 1 had a complicated one. In the analysis of SPECT images, while all the grafts with an uncomplicated clinical course exhibited increased uptake (grade 1-3), the failed graft showed decreased uptake (grade 6).ConclusionThree-phase bone scintigraphy performed within 10 days after the mandibular reconstruction is a useful tool to monitor the viability and early complications of vascularized mandibular bone grafts. SPECT is also recommended. It may contribute to interpretation of the bone scans and to precise assessment of graft viability.

Unfused renal ectopia: a rare form of congenital renal anomaly.

Unfused crossed renal ectopia observed 1 in 75,000 autopsies is a rare congenital anomaly. Typically one kidney is located in the proximity of the other kidney, and the ureter of the anatomically anomalous kidney crosses the midline to insert to the bladder in its normal anatomic position. Although renal function is usually not affected, the condition is generally accompanied by other congenital anomalies. In this case report, static and dynamic scintigraphic images of two patients with unfused crossed renal ectopia are presented. Besides properties of imaging modalities, clinical features are discussed in light of the available literature.

Discrepancy between Ga-67 citrate and F-18 fluorodeoxyglucose positron emission tomographic scans in pulmonary infection.

The authors describe a patient with the acquired immunodeficiency syndrome who had active pulmonary tuberculosis and was receiving anti-tuberculosis treatment. High-grade fever and a right-sided pleural effusion had recently developed. Results of a Ga-67 scan were negative for any focal infection in the chest. Fluorine-18 fluorodeoxyglucose positron emission tomography showed increased uptake in the right lower lung field, which correlated with the diagnosis of concomitant bacterial pneumonia. Anti-tuberculosis treatment can decrease the sensitivity of the Ga-67 scan and could have contributed to this discrepancy. The authors predict that the fluorine-18 fluorodeoxyglucose positron emission tomographic scan will play an important diagnostic role in the management of such a selected group of patients.

Washout rates of Tc-99m tetrofosmin in asymmetric septal hypertrophy

The aim of this study was to evaluate the washout rate of Tc-99m tetrofosmin in asymmetric septal hypertrophy (ASH). As Tc-99m tetrofosmin accumulation and retention depend on sarcolemmal and/or mitochondrial function, the presence or absence of abnormalities in the washout rate of Tc-99m tetrofosmin could provide information about sarcolemmal and/or mitochondrial damage noninvasively. The study group consisted of 18 patients with ASH and 10 healthy subjects. After intravenous injection of 1,110 MBq (30 mCi) Tc-99m tetrofosmin, tomographic images were obtained 1 hour later (early image) and again 4 hours later (delayed image). Using tomographic images, the distribution and washout of tetrofosmin in the left ventricle was examined quantitatively. Short-axis SPECT images were divided into 5 segments (anterior, septal, lateral, inferior wall and apex) in early and delayed images, and the mean radioactivity counts were measured in each segment by drawing regions of interest. Washout rates of apex, anterior, septal, lateral and inferior walls were 0.34 ± 0.06, 0.37 ± 0.07, 0.36 ± 0.07, 0.33 ± 0.08, 0.33 ± 0.07 in ASH and 0.20 ± 0.05, 0.23 ± 0.05, 0.22 ± 0.03, 0.21 ± 0.03, 0.22 ± 0.03 in the normal group, respectively. In ASH, the washout rates of all myocardial segments were significantly increased as compared to those of the normal controls (p < 0.05). The findings of the present study suggest that there could be dysfunction of sarcolemma and/or mitochondria in the entire left ventricle which would be important in the pathophysiology of this disease. Also our study revealed that Tc-99m tetrofosmin washout was higher in NYHA II—III patients compared to NYHA I patients and the degree of Tc-99m tetrofosmin washout corresponded well with the thickness of the interventricular septum and posterior walls.

Tc-99m MIBI uptake in traumatic vertebral fractures and metastatic vertebral lesions: Comparison with Tc-99m MDP

This study compared technetium-99m-hexakis-2-methoxyisobutyl-isonitrile (Tc-99m MIBI) with technetium-99m methylene diphosphonate (Tc-99m MDP) to determine whether Tc-99m MIBI could distinguish vertebral metastases from traumatic vertebral fractures. Twenty patients with traumatic vertebral fracture (and no malignant disease) and 14 patients with metastatic vertebral lesions were evaluated. Three to 4 hours after intravenous injection of Tc-99m MDP, images of the vertebrae in all patients were obtained. Corresponding Tc-99m MIBI images were acquired within 4 days after the Tc-99m MDP bone images were obtained. Computed tomography and magnetic resonance imaging demonstrated 24 vertebral traumatic fractures and 44 vertebral metastases. On conventional bone scans, Tc-99m MDP activity was increased in 92% of vertebral fractures and in 100% of vertebral metastases. However, on MIBI scans, no abnormal findings were observed in the vertebrae with fracture, although increased activity was seen in 73% of vertebral metastases. In this study, traumatic vertebral fractures tended to display no pathologic increases in Tc-99m MIBI uptake, whereas bone metastases usually appeared with high uptake. In light of the excellent specificity of Tc-99m MIBI scans compared with Tc-99m MDP bone scans, imaging studies that use Tc-99m MIBI scans may play an important complementary role in differentiating vertebral metastases from traumatic vertebral fractures.

Inguinal hernia detected during bone scintigraphy.

Bone scintigraphy is very sensitive for detecting the presence and extent of active bone disease. The most frequent indication is for detection of bony metastases in patients with cancer. Bone agents sometimes localize in soft tissue lesions. The author describes a 78-year-old man with prostate cancer and an inguinal hernia. Bone scintigraphy revealed increased soft tissue uptake in the region of the inguinal hernia.Bone scintigraphy is very sensitive for detecting the presence and extent of active bone disease. The most frequent indication is for detection of bony metastases in patients with cancer. Bone agents sometimes localize in soft tissue lesions. The author describes a 78-year-old man with prostate cancer and an inguinal hernia. Bone scintigraphy revealed increased soft tissue uptake in the region of the inguinal hernia.

Role of technetium-99m N,N-ethylenedicysteine renal scintigraphy in the evaluation of differential renal function and cortical defects.

Purpose: This study was performed to evaluate the effectiveness of technetium-99m N,N-ethylenedicysteine (Tc-99m EC) in comparison to technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy. Differential renal function (DRF) was calculated by both methods and the cortical-phase images of dynamic Tc-99m EC scintigraphy were evaluated for parenchymal defects. Materials and Methods: A total of 62 patients with various kidney disorders ranging in age from 1 to 44 years underwent both Tc-99m DMSA and Tc-99m EC scintigraphy. Tc-99m EC summed images of the cortical phase and Tc-99m DMSA images were evaluated visually and quantitatively. Visual analysis was used to define renal parenchymal abnormalities. Quantitative analysis was used in the calculation of DRF. The Tc-99m DMSA scan was taken as the gold standard, and the summed Tc-99m EC scan findings were compared against it. Results: The images obtained with Tc-99m DMSA and Tc-99m EC scintigraphy revealed 99 and 97 focal defects, respectively. The 2 renal parenchyma defects located in the ventral middle sections remained undetected with Tc-99m EC scintigraphy. DRF of the kidneys in each patient was compared using both radiopharmaceuticals. Highly positive correlation between the differential function of these 2 investigations was found (R = 0.91, P = 0.001). The values of mean DRF of the left kidney on Tc-99m EC and Tc-99m DMSA images were 45.8 ± 19.1 and 45.0 ± 20.4, respectively. There were no significant differences (P > 0.05). Conclusion: This study suggests that although Tc-99m DMSA scintigraphy remains the gold standard method for evaluating parenchymal abnormalities, Tc-99m EC scintigraphy can be a reliable single-modality study to evaluate renal cortical defects, DRF, perfusion, drainage of the urinary system, and indirect evidence of vesicoureteric reflux with the added advantage of low radiation exposure to the patient.

Interobserver and Intraobserver Variability among Measurements of FDG PET/CT Parameters in Pulmonary Tumors.

BACKGROUND 18F-fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT) provides information about metabolic and morphologic status of malignancies. Tumor size and standardized uptake value (SUV) measurements are crucial for cancer treatment monitoring. AIMS The purpose of our study was to assess the variability of these measurements performed by observers evaluating lung tumors. STUDY DESIGN Retrospective cross-sectional study. METHODS FDG PET/CT images of 97 patients with pulmonary tumors were independently evaluated by two experienced nuclear medicine physicians. Primary tumor size (UDCT), maximum SUV (SUVmax), mean SUV (SUVmean) and maximum SUV normalized to liver mean SUV (SUVnliv max) were measured by each observer at two different times with an interval of at least 2 weeks. Interobserver and intraobserver variabilities of measurements were evaluated through statistical methods. RESULTS Size of the lesions varied from 0.81 to 13.6 cm (mean 4.29±2.24 cm). Very good agreement was shown with correlation, Bland-Altman and regression analysis for all measured PET/CT parameters. In the interobserver and intraobserver variability analysis, the Pearson correlation coefficients were greater than 0.96 and 0.98, respectively. CONCLUSION Semi-quantitative measurements of pulmonary tumors were highly reproducible when determined by experienced physicians with clinically available software for routine FDG PET/CT evaluation. Consistency may be improved if the same observer performs serial measurements for any one patient.

Effectiveness of diuretic injection on the measurement of differential renal function using Tc-99m DMSA in patients with a dilated renal pelvis.

Aim: The aim of this study was to evaluate the effectiveness of diuretic injection for the measurement of differential renal function (DRF) with technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy in patients with a dilated pelvis. Materials and Methods: A total of 46 patients who were referred for both technetium-99m-L,L-ethylenedicysteine (Tc-99m L,L-EC) and Tc-99m DMSA imaging and found to have a dilated collecting system on Tc-99m EC scintigraphy were studied. Four to 5 hours after intravenous injection of Tc-99m DMSA, imaging was performed in the supine position, and posterior, anterior, left and right lateral, and left and right posterior oblique views were taken. After this study, furosemide was administered intravenously and 30 minutes later, additional images in the anterior and posterior views were obtained. Results: The kidneys were evaluated into 2 groups. Group 1 comprised 12 kidneys that had an obstructive curve pattern on Tc-99m EC scans. Group 2 comprised 34 kidneys that had a nonobstructive dilated renogram curve pattern. DRF of the kidneys in each patient were calculated, and the values obtained from the standard and diuretic DMSA scans were compared with each other for all patients and each group. Considering all the patients, the values of mean DRF on both standard and diuretic DMSA images were 55.4% ± 21.2% and 55.4% ± 21.5%, respectively. There were no significant differences between DRF values of each kidney obtained by the 2 methods. When we compared the DRF values in groups 1 and 2, there were again no significant differences. In group 1, the values of mean DRF on standard and diuretic images were 51.7% ± 13.7% and 51.6% ± 13.9%, respectively, and in group 2, the values of mean DRF were 56.7% ± 23.4% and 56.7% ± 23.6%, respectively. Conclusion: In view of our study, diuretic administration seems to be an unnecessary intervention because it has no effect on the accuracy of DRF measurements using DMSA scintigraphy in patients with a dilated collecting system whether it is obstructed or not.

Tc-99m MAG3 scintigraphy in unusually dilated bilateral extrarenal pelves.

The authors report the findings of a radionuclide diuretic renogram in a patient with markedly dilated pelves bilaterally that filled most of the abdominal cavity. With the patient in the sitting position, at the end of the furosemide injection, there was good delineation and filling of the dilated calyces. These findings are unusual because of the extensive pelvicaliceal dilatation, and they emphasize the importance of the sitting position.