Semi-quantitative evaluation of gallium-67 scintigraphy in lupus nephritis

Within nuclear medicine there is a trend towards quantitative analysis. Gallium renal scan has been reported to be useful in monitoring the disease activity of lupus nephritis. However, only visual interpretation using a four-grade scale has been performed in previous studies, and this method is not sensitive enough for follow-up. In this study, we developed a semi-quantitative method for gallium renal scintigraphy to find a potential parameter for the evaluation of lupus nephritis. Forty-eight patients with lupus nephritis underwent renal biopsy to determine World Health Organization classification, activity index (AI) and chronicity index (CI). A delayed 48-h gallium scan was also performed and interpreted by visual and semi-quantitative methods. For semi-quantitative analysis of the gallium uptake in both kidneys, regions of interest (ROIs) were drawn over both kidneys, the right forearm and the adjacent spine. The uptake ratios between these ROIs were calculated and expressed as the "kidney/spine ratio (K/S ratio)" or the "kidney/arm ratio (K/A ratio)". Spearman's rank correlation test and Mann-Whitney U test were used for statistical analysis. Our data showed a good correlation between the semi-quantitative gallium scan and the results of visual interpretation. K/S ratios showed a better correlation with AI than did K/A ratios. Furthermore, the left K/S ratio displayed a better correlation with AI than did the right K/S ratio. In contrast, CI did not correlate well with the results of semi-quantitative gallium scan. In conclusion, semi-quantitative gallium renal scan is easy to perform and shows a good correlation with the results of visual interpretation and renal biopsy. The left K/S ratio from semi-quantitative renal gallium scintigraphy displays the best correlation with AI and is a useful parameter in evaluating the disease activity in lupus nephritis.     

Effect of imaging time on gallium renal scan

AIM: Gallium renal imaging has been reported to be useful in monitoring disease activity and predicting the response to therapy in lupus nephritis. Gallium renal images are usually obtained 48 h after the injection of 67Ga citrate, but 72-h images sometimes are the only available pictures. The aim of the present study was to determine whether the time intervals from injection to imaging had any effect on the grading of gallium renal scintigraphy. METHODS: Fifty-five patients with lupus nephritis underwent gallium renal imaging at both 48 h and 72 h post-injection of 111 MBq of 67Ga citrate. The relative uptakes of 67Ga by the kidneys and the spine was judged visually on the analog images. Renal uptake was rated on a scale of 0-3. RESULTS: Fifty-three patients (96.3%) had the same grading of renal uptake in the 48-h and the 72-h images. Only two patients (3.7%) had a different grading in the 72-h images when compared to the 48-h images. The correlation between the 48-h renal uptake and 72-h renal uptake was excellent, with a Spearman R value of 0.94. No significant difference was noted between these two groups, with a P value of 0.76 (using a Wilcoxon matched pairs test). CONCLUSION: A gallium renal scan can be obtained either 48 h or 72 h after injecting 67Ga citrate. The imaging time did not interfere with the grading of renal uptake in lupus nephritis.     

A high-fibre diet in combination with bisacodyl for bowel preparation in gallium renal scintigraphy

Bowel accumulation of gallium-67 frequently complicates the interpretation of gallium-67 scintigrams. This is a drawback, especially when reading gallium renal images. In this study, we evaluated the value of a high-fibre diet in bowel preparation for improving the quality of gallium renal imaging in lupus nephritis. Group A, consisting of 86 patients, was on a regular diet and received bisacodyl the night before imaging. Group B, consisting of 77 patients, was on a high-fibre diet for three consecutive days before imaging and received bisacodyl the night before imaging. Gallium bowel activity was rated on a scale of 0 to III on the basis of anterior and posterior views of delayed 48 h images. Our data revealed that there was a significant difference in image quality between groups A and B. Fifty per cent of group A patients had obvious bowel activity. The percentage decreased significantly to 25% in group B. In conclusion, the application of a high-fibre diet significantly improves the efficacy of bowel preparation for gallium renal scintigraphy in the evaluation of lupus nephritis.     

A clinical assessment of the relationship between bone scintigraphy and serum biochemical markers in hemodialysis patients

BACKGROUND: Renal osteodystrophy is a metabolic bone disease and a common complication of end-stage chronic renal failure and maintenance dialysis treatment. In this study, we examined the correlation between quantifying bone scintigraphy and serum biochemical markers in hemodialysis patients. METHODS: Bone scintigraphy with technetium-99m-hydroxy-methylene-diphosphonate (99mTc-HMDP) was performed on 28 patients on maintenance hemodialysis. Bone scintigraphy was performed using a standard protocol and was quantified by setting regions of interest (ROIs) over selected regions. The bone-to-soft-tissue ratio (B/ST ratio) at each region was calculated in all patients. The B/ST ratios were then compared with serum biochemical markers. RESULTS: The B/ST ratio for the skull correlated well with serum bone-specific alkaline phosphatase (BAP) (r = 0.735, p < 0.001), serum deoxypyridinoline (DPD) (r = 0.806, p < 0.001) and intact parathyroid hormone (intact PTH) (r = 0.701, p < 0.001). The B/ST ratio for the lumbar spine correlated with intact PTH (r = 0.387, p < 0.05) but not with serum BAP or serum DPD. The B/ST ratio for the femoral neck correlated with serum DPD (r = 0.431, p < 0.05) and intact PTH (r = 0.449, p < 0.05) but not with serum BAP. CONCLUSIONS: Our data suggest that quantitative bone scintigraphy is a sensitive and useful method for evaluating bone metabolism in hemodialysis patients. The B/ST ratio for the skull may reflect changes of bone metabolism in hemodialysis patients.     

Evaluation of renal function with 99mTc-MAG3 using semiautomated regions of interest.

The need to draw regions of interest (ROIs) manually may reduce the convenience and reliability of estimating renal function from renal scintigraphy. We developed a semiautomated method to define ROIs for renal scintigraphy with 99mTc-mercaptoacetyltriglycine (MAG3) and evaluated the clinical applicability of the method to the estimation of renal function by camera-based methods. METHODS: Dynamic renal scintigraphy with 99mTc-MAG3 was performed on 21 patients. An operator placed a large rectangular ROI over each kidney, a circular ROI within the liver, and a rectangular ROI between the kidneys. Using these ROIs, semiautomated renal ROIs were determined on the basis of the temporal changes in counts, in addition to the absolute counts, and a subrenal background ROI was automatically assigned for each renal ROI. Background-subtracted renograms were generated using these renal and subrenal ROIs, and renogram parameters were derived from the slope of the renogram and the area under the renogram. Clearance was calculated using the renogram parameters and equations determined previously with manual ROIs and correlated with clearance measured by a single-sample method. The relative function of the right kidney determined by the semiautomated method was compared with that determined by the manual method. Data processing was performed independently by another operator to assess interoperator reproducibility. RESULTS: ROIs defined by the semiautomated method were visually judged to be acceptable for clinical use in all patients with a wide range of renal function. Clearance was successfully predicted with the semiautomated ROIs (r = 0.968 using the slope of the renogram; r = 0.934 using the area under the renogram), and relative function calculated with the semiautomated ROIs was almost identical to that calculated with manual ROIs. There was almost complete concordance in absolute and relative function between the two operators. CONCLUSION: The semiautomated method can define ROIs for 99mTc-MAG3 renal scintigraphy with limited operator intervention. Camera-based methods using the semiautomated ROIs allow estimation of renal function with high accuracy and little interoperator variability and are suggested to be suitable for clinical use.     

Usefulness of bone uptake ratio of bone scintigraphy in hemodialysis patients

OBJECTIVE: It is important to estimate the bone metabolism in patients with renal osteodystrophy. The methods of estimation must be noninvasive, accurate, and able to measure repeatedly. METHODS: The regions of interest on bone scintigraphy were drawn over the radius in 22 hemodialysis patients (10 males, 12 females). The bone/soft tissue ratio (B/ST ratio) was calculated for all patients. The bone soft tissue ratio of both skull (S) and radius (R) was obtained from the resultant count ratios. We investigated the correlation between intact parathyroid hormone (PTH), alkaline phosphatase (ALP) and the uptake ratios S and R. RESULTS: Intact PTH had a significantly linear correlation with R (r = 0.745, p < 0.0001) and S (r = 0.702, p = 0.0001). ALP also had a significantly linear correlation with R (r = 0.537, p = 0.009) and S (r = 0.772, p < 0.0001). CONCLUSION: The measurement of the bone soft tissue ratio of radius on bone scintigraphy was crucial for estimating renal osteodystrophy.     

Gallium-67 scintigraphy in the detection of infected polycystic kidneys in renal transplant recipients

Renal transplant recipients with underlying polycystic kidney disease (PKD) may present with recurrent urinary tract infection (UTI). This is often due to persistent infection in one or both of the native polycystic kidneys. It may be necessary to remove the infected kidney in order to remove the source of persistent infection. Gallium-67 scintigraphy was performed in 11 renal transplant recipients with underlying PKD. Positive studies were obtained in four recipients who had recurrent UTI. The scan also localized which of the kidneys (native or transplant) was the site of persistent infection. These four recipients subsequently had nephrectomy of the infected polycystic kidneys as suggested by the scan. Negative scans were obtained in seven recipients who did not have recurrent UTI. Gallium scintigraphy is a useful test for detecting and localizing the site of persistent UTI in renal transplant recipients with underlying PKD who present with recurrent UTI.     

SPECT gallium-67 scanning in early human immunodeficiency virus (HIV) infection. Failure of scanning abnormalities to correlate with immunologic staging

The use of gallium scanning in the treatment of patients with AIDS has been well described. In this study, 27 HIV-infected patients (Walter Reed Staging Classification I-V) with normal chest roentgenograms were evaluated to determine the occurrence of thoracic gallium abnormalities in early HIV infection. SPECT was used for gallium scanning. Patients received gallium injection on day 1 and bronchoalveolar lavage on day 2, and scanning was performed on day 3. Twenty-eight scans in 27 patients were performed. Mean nodal SPECT activity was compared with corresponding values for lung parenchyma, bronchoalveolar lavage cell counts, and peripheral blood T4 lymphocyte counts. No relationship between nodal and parenchymal activity and cell counts was observed. Although visual scan interpretation was unaffected, gallium activity was significantly increased in the region of bronchoalveolar lavage compared with uptake in other lung regions. It is concluded that SPECT gallium scanning demonstrates significant gallium avidity in recently lavaged lung areas, although no impact on visual scan interpretation was seen. Further, no correlation was seen between the degree of nodal uptake and the immunologic status of these patients with early HIV infection.     

Quantitative analysis of 99mTc-DMSA during acute pyelonephritis for prediction of long-term renal scarring.

This study was performed to evaluate a quantitative method based on (99m)Tc-DMSA renal planar scintigraphy performed during acute pyelonephritis (APN) to detect kidneys at risk of scarring. METHODS: A total of 43 children (5.8 +/- 3.6 y old [mean +/- SD]) were examined by (99m)Tc-DMSA scintigraphy during (DMSA 1) and 8 +/- 2 mo after (DMSA 2) APN. Two levels of interpretation were performed independently: first, a semiquantitative analysis to classify the kidneys by considering the evolution between DMSA 1 and DMSA 2 (i.e., to determine which kidneys had developed scarring), and second, an automatic quantitative analysis of DMSA 1 to define and to evaluate a predictive index for kidney evolution from DMSA 1 to DMAS 2. The method consisted of determining an automatic threshold for the kidney and then calculating ratios of the count density in a given isocount n% (region of interest containing all the pixels with a value > or = n% of the value of the pixel with the maximal activity value) to the count density in a 20% isocount (C(n%)) and the number of pixels in a given isocount to the number of pixels in a 20% isocount (S(n%)). RESULTS: All kidneys normal at DMSA 1 remained normal at DMSA 2. For the automatic index, the C(70%) ratio was considered the best index for the prediction of scarring. When this C(70%) ratio was used, a cutoff value of 0.45 was able to predict scarring with a sensitivity of 0.83, a specificity of 0.78, a positive predictive value of 0.85, and a negative predictive value of 0.77. CONCLUSION: A cutoff value of 0.45 for the C(70%) ratio calculated for (99m)Tc-DMSA scintigraphy performed during APN may be useful for detecting kidneys at risk of scarring.     

Relationship between the renal apparent diffusion coefficient and glomerular filtration rate: preliminary experience

PURPOSE: To investigate the relationship between ADC values measured by diffusion-weighted MRI (DWI) and the split glomerular filtration rate (GFR). MATERIALS AND METHODS: DWI (b = 0 and 500 seconds/mm(2)) was performed with a 1.5 T MR unit in 55 patients. The ADCs were calculated with ROIs positioned in the renal parenchyma, and the split GFRs were measured by (99)Tc(m)-DTPA scintigraphy using Gates' method. The 110 kidneys were divided into four groups: normal renal function (GFR 40 mL x minute(-1)), mild renal impairment (40 > GFR > or = 20 mL x minute(-1)), moderate renal impairment (20 > GFR > or = 10 mL x minute(-1)), and severe renal impairment (GFR < 10 mL x minute(-1)). The renal ADCs between four groups were statistically compared by analysis of variance (ANOVA), and the relationship between ADCs and GFR was examined using Pearson's correlation test. RESULTS: The mean renal ADCs of the four groups were 2.87 +/- 0.11, 2.55 +/- 0.17, 2.29 +/- 0.10, and 2.20 +/- 0.11 x 10(-3)mm(2)/second, respectively. There was a statistically significant difference in renal ADCs among the four groups (P < 0.001). There was a positive correlation between the ADCs and split GFR (r = 0.709). CONCLUSION: The ADCs were significantly lower in impaired kidneys than in normal kidneys, and there was a positive correlation between the ADCs and GFR.     

Single-dose captopril scintigraphy in the diagnosis of renovascular hypertension

Renal scintigraphy with [99mTc]diethylenetriaminepentaacetic acid (DTPA) and/or sodium-iodine-131-o-iodohippurate (HIP) was performed before and after an oral dose of captopril (50 mg) in 18 patients with renovascular hypertension (RVH) due to renal artery stenosis (RAS) and 18 controls. In every patient with RVH, captopril induced, enhanced or sustained abnormal findings on HIP scintigraphy depending on the degree of RAS. With DTPA scintigraphy, renal function decreased after captopril in ten kidneys with RVH-related RAS and adequate baseline renal function, but this phenomenon was not evident in 11 kidneys with RVH and poor renal function. Captopril did not influence HIP or DTPA studies of kidneys with patent renal arteries (patients after successful renal angioplasty, patients with essential hypertension, contralateral kidneys of patients with unilateral RVH) or ipsilateral kidneys with mild and subcritical (less than 60%) RAS in patients without hypertension and/or normal renal vein renin activity. When HIP and DTPA scintigraphy were compared in the same patients, HIP demonstrated greater sensitivity and specificity than DTPA, particularly in patients with poor renal function. HIP scintigraphy before and after a single dose of captopril may provide a rapid sensitive and minimally invasive test for screening patients with hypertension.     

Functional evaluation of hydronephrosis by diffusion-weighted MR imaging. Relationship between apparent diffusion coefficient and split glomerular filtration rate

PURPOSE: To determine the relationship between apparent diffusion coefficient (ADC) values measured by diffusion-weighted MR imaging and split renal function determined by renal scintigraphy in patients with hydronephrosis. MATERIAL AND METHODS: Diffusion-weighted imaging on a 1.5 T MR unit and renal scintigraphy were performed in 36 patients with hydronephrosis (45 hydronephrotic kidneys, 21 non-hydronephrotic kidneys). ADC values of the individual kidneys were measured by diffusion-weighted MR imaging. Split renal function (glomerular filtration rate (GFR)) was determined by renal scintigraphy using 99mTc-DTPA. The relationship between ADC values and split GFR was examined in 66 kidneys. The hydronephrotic kidneys were further classified into three groups (severe renal dysfunction, GFR <10 ml/min, n=7; moderate renal dysfunction, GFR 10-25 ml/min, n= 10; normal renal function, GFR >25 ml/ min, n=28), and mean values for ADCs were calculated. RESULTS: In hydronephrotic kidneys, there was a moderate positive correlation between ADC values and split GFR (R2=0.56). On the other hand, in nonhydronephrotic kidneys, poor correlation between ADC values and split GFR was observed (R2=0.08). The mean values for ADCs of the dysfunctioning hydronephrotic kidneys (severe renal dysfunction, 1.32 x 10(-3) +/- 0.18 x 10(-3) mm2/s; moderate renal dysfunction, 1.38 x 10(-3) +/- 0.10 x 10(-3) mm2/s) were significantly lower than that of the normal functioning hydronephrotic kidneys (1.63 x 10(-3) +/- 0.12 +/- 10(-3) mm2/s). CONCLUSION: These results indicated that measurement of ADC values by diffusion-weighted MR imaging has a potential value in the evaluation of the functional status of hydronephrotic kidneys.     

The scintigraphic pattern of renal angiomyolipoma

The patterns of renal and gallium scintigraphy in a patient with renal angiomyolipoma are presented. Renal study with Tc-99m DTPA demonstrated a photopenic area in the flow and delayed images. Ga-67 citrate imaging did not show any evidence of increased activity. Although this pattern is also seen in renal cysts, scintigraphy seems to be valuable in the evaluation of angiomyolipoma. It helps differentiate it from renal carcinoma or renal abscess (which may be gallium avid), especially when the tumor is characterized by a paucity of adipose tissue and complicated by hemorrhage, in which case CT and ultrasonographic patterns are not diagnostic.     

Gallium-67 scintigraphy in lymphoma: is there a benefit of image fusion with computed tomography?

The usefulness and complementarity of gallium (67Ga) scintigraphy and computed tomography (CT) in the management of patients with lymphoma have been extensively demonstrated. Owing to a lack of anatomical landmarks and physiological distribution of the tracer, precise localisation of abnormalities on 67Ga scintigraphy can be difficult. As fusion imaging techniques between single-photon emission tomography (SPET) and CT have been developed recently, we investigated whether use of CT/67Ga SPET fusion imaging could help in the interpretation of 67Ga scintigraphy. From November 1999 to May 2001, 52 consecutive fusion studies were performed in 38 patients [22 patients with Hodgkin's disease (HD) and 16 patients with non-Hodgkin's lymphoma (NHL)] as part of pre-treatment staging (n=13), treatment evaluation (n=20) or evaluation of suspected recurrence (n=19). 67Ga scintigraphy was carried out 2 and 6 days following the injection of 185-220 MBq 67Ga citrate. On day 2, 67Ga SPET and CT were performed, focussing on the chest and/or the abdomen/pelvis. Data from each imaging method were co-registered using external markers. 67Ga scintigraphy and CT were initially interpreted independently by nuclear medicine physicians and radiologists. CT/67Ga SPET fusion studies were then jointly interpreted and both practitioners indicated when fusion provided additional information in comparison with CT and 67Ga SPET alone. Image fusion was considered to be of benefit in 12/52 (23%) studies which were performed for initial staging (n=4), treatment evaluation (n=4) or evaluation of suspected recurrence (n=4). In these cases, image fusion allowed either confirmation and/or localisation of pathological gallium uptake (n=10) or detection of lesions not visible on CT scan (n=2). Fusion was relevant for discrimination between osseous lesions and lymph node involvement adjacent to bone, especially in the thoracic and lumbar spine and pelvis. In the abdomen and pelvis, fusion helped to differentiate physiological bowel elimination from abnormal uptake, and assisted in precisely locating uptake in neighbouring viscera of the left hypochondrium, including the spleen, left liver lobe, coeliac area, stomach wall and even the splenic flexure. At the thoracic level, fusion also proved useful for demonstrating clearly the relationships of abnormal foci to the pleura, hepatic dome, mediastinum, ribs or thoracic spine. Clinical management was altered by fusion imaging in one patient (chemotherapy was given instead of radiotherapy) and was potentially affected in three other patients (in that, in conjunction with other factors, the results of fusion imaging had an influence on the decision regarding use of irradiation and especially the treatment volume). In conclusion, CT/67Ga SPET fusion imaging allowed precise localisation of gallium uptake and correct attribution to the involved viscera, thereby altering the diagnosis in 20%-25% of studies in comparison with CT and 67Ga SPET analyses alone. CT/67Ga SPET fusion therefore appears valuable in facilitating the interpretation of 67Ga scintigraphy and we recommend its use in patients with lymphoma when CT and 67Ga scintigraphy are planned.     

The role of Gallium-67 imaging in the detection of foci in recent cases of fever of unknown origin

We have assembled data from patients with fever of unknown origin who underwent gallium scintigraphy during the past 5 years in order to obtain a more current sampling of patients, and evaluated the role of gallium scintigraphy retrospectively. Of the 36 patients studied, gallium scintigraphy was positive and contributed to the detection of the foci or fever origins in 17 (47.2%). The ratio of neoplastic diseases with myeloproliferative and with lymphoproliferative disorders was relatively high compared with previous reports. However, gallium scintigraphy did not contribute to the diagnosis of collagen disease. With the ability to detect both inflammatory and neoplastic lesions, gallium scintigraphy was useful in detecting the foci of fevers of unknown origin.     

Adult polycystic disease of kidneys: a potential cause of false-positive 67Ga images

A 56-year-old man with adult polycystic disease of the kidneys complicated by renal failure, hypertension, and bacteremia underwent bilateral nephrectomy because the enlarged kidneys compromised his gastrointestinal function and respiratory capacity. A scan using 99mTc-methylene diphosphonate demonstrated nonfunctioning kidneys, bilaterally. An unusual radioactivity pattern in the bowel in 67Ga scintigraphy was due to extreme renal enlargement and should be kept in mind to avoid misinterpretation.     

Reliability of DMSA for the diagnosis of renal parenchymal abnormality in children

The objective of this study was to evaluate the variability of technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy interpretation by four nuclear medicine physicians for the diagnosis of renal parenchymal abnormality in children, and to compare variability among three different DMSA methods in clinical use: planar alone, single-photon emission tomography (SPET) alone, and planar with SPET. One hundred consecutive DMSA studies were independently interpreted 3 times by four participating nuclear medicine specialists from different departments and in random order. All scans were classified by the presence or absence of renal parenchymal abnormality using the modified four-level grading system of Goldraich. Indices of agreement were the percentage of agreement and the kappa statistic. Disagreement was analysed using children, kidneys and kidney zones (three zones per kidney). Using patients as the unit of analysis, agreement for planar and planar with SPET methods was 87%-88% (kappa 0.74) for the normal-abnormal scan classification. The corresponding agreement value for the SPET alone method was 78% (kappa 0.56). Similarly, substantial disagreement (disagreement > or = 2 categories) occurred in 2.5% and 1.3% of comparisons between observers for planar alone and planar with SPET, respectively, but in 5.2% of comparisons for SPET alone. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. It is concluded that the four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone and planar with SPET DMSA scintigraphic images. Interpretation of SPET DMSA images, without planar images, was significantly more variable than interpretation using the two other methods, disagreement occurring in more than 20% of comparisons. SPET DMSA scintigraphy, when used without planar images, does not provide a firm basis for clinical decision making in the care of children who may have renal damage. There is no apparent benefit of reduced variability from the extra provision of SPET data to nuclear medicine physicians who already have planar images.     

Reliability of DMSA for the diagnosis of renal parenchymal abnormality in children

The objective of this study was to evaluate the variability of technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy interpretation by four nuclear medicine physicians for the diagnosis of renal parenchymal abnormality in children, and to compare variability among three different DMSA methods in clinical use: planar alone, single-photon emission tomography (SPET) alone, and planar with SPET. One hundred consecutive DMSA studies were independently interpreted 3 times by four participating nuclear medicine specialists from different departments and in random order. All scans were classified by the presence or absence of renal parenchymal abnormality using the modified four-level grading system of Goldraich. Indices of agreement were the percentage of agreement and the kappa statistic. Disagreement was analysed using children, kidneys and kidney zones (three zones per kidney). Using patients as the unit of analysis, agreement for planar and planar with SPET methods was 87%-88% (kappa 0.74) for the normal-abnormal scan classification. The corresponding agreement value for the SPET alone method was 78% (kappa 0.56). Similarly, substantial disagreement (disagreement ̀ categories) occurred in 2.5% and 1.3% of comparisons between observers for planar alone and planar with SPET, respectively, but in 5.2% of comparisons for SPET alone. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. It is concluded that the four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone and planar with SPET DMSA scintigraphic images. Interpretation of SPET DMSA images, without planar images, was significantly more variable than interpretation using the two other methods, disagreement occurring in more than 20% of comparisons. SPET DMSA scintigraphy, when used without planar images, does not provide a firm basis for clinical decision making in the care of children who may have renal damage. There is no apparent benefit of reduced variability from the extra provision of SPET data to nuclear medicine physicians who already have planar images.     

Impact of metallic dental implants on CT-based attenuation correction in a combined PET/CT scanner

Our objective was to study the effect of metal-induced artifacts on the accuracy of the CT-based anatomic map as a prerequisite for attenuation correction of the positron emission tomography (PET) emission data. Twenty-seven oncology patients with dental metalwork were enrolled in the present study. Data acquisition was performed on a PET/CT in-line system (Discovery LS, GE Medical Systems, Milwaukee, Wis.). Attenuation correction of emission data was done twice, using an 80-mA CT scan (PET_CT80) and a ⁶⁸Ge transmission scan (PET_68Ge). Average count in kBq/cc was measured in regions with and without artifacts and compared for PET_CT80 and PET_68Ge. Data analysis of region of interests (ROIs) revealed that the ratio (ROIs PET_CT80/ROIs PET_68Ge) and the difference (ROIs PET_CT80 minus ROIs PET_68Ge) had a higher mean of values in regions with artifacts than in regions without artifacts (1.2±0.17 vs 1.06±0.06 and 0.68±0.67 vs 0.15±0.17 kBq/cc, respectively). For most of the studied artifactual ROIs, the PET_CT80 values were higher than those of the PET_68Ge. Attenuation correction of PET emission data using an artifactual CT map yields false values in regions nearby artifacts caused by dental metalwork. This may falsely estimate PET quantitative studies and may disturb the visual interpretation of PET scan. Electronic Publication     

Does the application of gadolinium-DTPA have an impact on magnetic resonance phase contrast velocity measurements? Results from an in vitro study

Percutaneous renal biopsy is a useful diagnostic procedure for many renal diseases. The experience with ultrasound-guided percutaneous renal biopsy from a single operator was reviewed to identify the possible risk factors of complications after the procedure. METHODS AND RESULTS: From 1995 to 1998, 203 biopsies (141 on native kidneys with 14G needles, 62 on transplant kidneys with 18G needles) were performed on 186 individuals as clinically indicated. The biopsy tissue specimen was adequate for histological diagnosis in 96.4% of the biopsies performed. IgA nephropathy followed by lupus nephritis were the most frequent diagnoses in our locality. Haematuria was the most common complication observed: mild bleeding occurred in 4.5%, while major complications (those that required blood transfusion or other intervention) were encountered in 1.5% of patients. Impaired renal function was identified as the single most important risk factor of bleeding complication after renal biopsy, while the presence of systemic hypertension or nephrotic syndrome did not increase the risk of bleeding. There was no correlation between bleeding and the type of renal pathology or the number of needle passes. Continuous haematuria may result from blood clot retention in the bladder. Over 97% of the cases were discharged from hospital within 48 h. CONCLUSIONS: We conclude that ultrasound-guided renal biopsy remains a safe, fast, and accurate procedure for the definitive investigation of renal diseases.