Quantitative biomarkers for liver metastases: comparison of MRI diffusion-weighted imaging heterogeneity index and fluorine-18-fluoro-deoxyglucose standardised uptake value in hybrid PET/MR.

AIM: To investigate the ability of apparent diffusion coefficient (ADC) heterogeneity index to discriminate liver metastases (LM) from normal-appearing liver (NAL) tissue as compared to common magnetic resonance imaging (MRI) metrics, and to investigate its correlation with 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) positron-emission tomography (PET) standardised uptake value (SUV). MATERIALS AND METHODS: Thirty-nine liver metastases in 24 oncology patients (13 women, 11 men; mean age 56±13 years) with proven LM from heterogeneous sources were evaluated on a PET/MRI system. Abdominal sequences included Dixon and diffusion-weighted imaging (DWI) protocols with simultaneous PET. Tissue heterogeneity was calculated using the coefficient of variance (CV) of the ADC, and compared in LM and in NAL tissue of the same volume in an adjacent portion of the liver. The correlations between various ADC measures and PET SUV in distinguishing LM from NAL were evaluated. RESULTS: A good correlation was found between ADCcv and SUVpeak (r=0.712). Moderate inverse correlation was found between ADCmin and SUVpeak (r=-0.536), and a weak inverse correlation between ADCmean and SUVpeak (r=-0.273). There was a significant difference between LM and NAL when ADCcv (p<0.0001) and ADCmin (p=0.001) were used. Receiver operating characteristic (ROC) analysis of SUV, ADCcv, ADCmin, and ADCmean produced an AUC of 0.989, 0.900, 0.742, and 0.623 respectively. CONCLUSIONS: The ADCcv index is a potential biomarker of LM with better correlation to 18F-FDG PET SUVpeak than conventional MRI metrics, and may serve to quantitatively discriminate between LM and NAL.

Early 68GA-PSMA PET/MRI acquisition: assessment of lesion detectability and PET metrics in patients with prostate cancer undergoing same-day late PET/CT.

AIM: To compare lesion detectability and positron-emission tomography (PET) metric measurements between early-PET/magnetic resonance imaging (MRI) acquisition and same-day PET/computed tomography (CT). MATERIALS AND METHODS: The study was approved by the institutional review board and written informed consent was obtained from all patients. Twenty-one patients underwent non-time-of-flight (TOF) PET/MRI immediately following 68GA-prostate-specific membrane antigen (PSMA) tracer injection in two steps: firstly, early prostate PET/MRI (pPET/MRI) and early whole-body (WB) PET/MRI (wbPET/MR) followed by WB TOF PET/CT (wbPET/CT). Lesion detectability was compared between wbPET/MRI and wbPET/CT while PET metric measurements were compared between pPET/MR, wbPET/MRI, and wbPET/CT. RESULTS: Sixty-one and 63 lesions were found on wbPET/MRI and wbPET/CT, respectively (K=0.95, 95% confidence interval (CI)=0.89-1.0) with very good correlation between PET metric measurements (r=0.91; p=0.001). Bland-Altman plots demonstrated a mean percentage difference between wbPET/CT with wbPET/MRI of 34.4% with 95% limits of agreement (LOA) between -39% to 107.9% for metabolic tumour volume (MTV) and a mean difference of 30% with LOA between -13.4% to 73.4% for peak standardised uptake value (SUVpeak). CONCLUSION: Early PET/MRI demonstrates very good lesion detectability agreement and correlation with PET metrics compared to same-day PET/CT. Nevertheless, LOA are far beyond the clinically acceptable range, and therefore, PET/CT and early PET/MRI metrics cannot be used interchangeably.

The Role of 18F-FDG PET/CT on Staging and Prognosis in Patients with Small Cell Lung Cancer.

BACKGROUND: We evaluated 18F-FDG PET/CT in small cell lung cancer (SCLC) staging and assessed metabolic (SUVmax, MTV and TLG) and morphologic (CTvol) variables as predictors for overall survival (OS) and progression-free survival (PFS). METHODS: Patients with newly diagnosed, histopathology-confirmed SCLC, who underwent 18F-FDG PET/CT were evaluated. A Cox proportional hazard model was used to determine the association between the primary tumour SUVmax, MTV, TLG and CTvol with OS and PFS. Similar evaluations were performed when hilar/mediastinal lymphadenopathy was included [total SUVmax (TSUVmax), total MTV (TMTV) and total TLG (TTLG)]. RESULTS: 55 patients were included. 18F-FDG PET/CT changed staging in 6/55 (10.9%) patients who were upstaged to extensive disease. TTLG (>443.8) was a significant variable for OS with HR=2.1 (CI 1.14-3.871, p=0.017). Patients with TTLG>443.8 had a median OS of 13.4 months compared to 25.7 months in patients with TTLG<443.8 (p=0.018). TMTV (>72.4) was significant for PFS with HR=2.3 (CI 1.11-4.8, p=0.025). A median PFS of 12.1 and 26.2 months was found with TMTV greater and less than 72.4, respectively (p=0.005). CONCLUSIONS: 18F-FDG PET/CT improved staging of patients with SCLC, and TTLG and TMTV can be used as prognostic variables for OS and PFS, respectively. KEY POINTS: • Identifying variables that predict the prognosis of patients with SCLC is important. • 18F-FDG PET/CT influences staging of patients with SCLC. • Metabolic parameters could be used as predictors for PFS and OS.

Survival Prognostic Value of Morphological and Metabolic variables in Patients with Stage I and II Non-Small Cell Lung Cancer.

BACKGROUND: The prognosis of patients with non-small cell lung cancer (NSCLC) is important, as patients with resectable disease and poor prognostic variables might benefit from neoadjuvant therapy. The goal of this study is to evaluate SUVmax, SUVmax ratio, CT volume (CTvol), metabolic tumour volume (MTV) and total lesion glycolisis (TLG) as survival prognostic markers. In addition, we defined two variables; MTV x SUVmax (MTVmax) and CTvol x SUVmax (CTvolmax) and assessed whether they can be used as prognostic markers. METHODS: Patients with stage I-II NSCLC who underwent 18 F FDG PET/CT and surgery were evaluated. Cox proportional-hazard model was used to determine the association between variables and survival. Similar analysis was performed in cases with no lymph node (LN) involvement. RESULTS: One hundred and eighty-one patients were included (at the end of the study, 140 patients were alive). SUVmax with a cut-off value of 8.2 was significant survival prognostic factor regardless of LN involvement (P = 0.012). In cases with no LN involvement, SUVmax and CTvol (≥7.1 ml) were significant survival prognostic factors with P = 0.004 and 0.03, respectively. CONCLUSIONS: SUVmax may be a useful prognostic variable in stage I-II NSCLC while morphologic tumour volume might be useful in cases with no lymph node involvement. KEY POINTS: • Identifying variables that predict the prognosis of patients with NSCLC is important. • SUVmax in primary lung tumour is a useful independent prognostic variable. • (CTvol) is an independent prognostic variable if no lymph nodes are involved.

Comparison of 80 and 120 kVp contrast-enhanced CT for attenuation correction in PET/CT, using quantitative analysis and reporter assessment of PET image quality.

AIM: To determine the effect of low tube voltage on positron-emission tomography (PET) image quality, quantitative analysis, and radiation dose in a combined PET/computed tomography (CT) study in patients with normal body mass index (BMI). MATERIALS AND METHODS: One hundred and twenty-nine examinations performed in 46 patients (mean age 57 years), who had at least two separate studies were retrospectively evaluated; at least one with 120 kVp and one with 80 kVp. Three independent readers reviewed all PET images and graded the image quality. PET signal and noise were recorded on the liver, spleen, fat, bone marrow, and aorta. CT dose index (CTDI) and the dose-length product (DLP) were used for CT radiation dose estimation. A mixed-effects model analysis was used for comparison of estimated radiation dose and PET data. RESULTS: There was a significant decrease of 15% in the radiation dose estimates between 80 and 120 kVp (DLP 946.2 ± 189 versus 1157.0 ± 236, respectively; p < 0.001). There was an increase of 12% in PET signal in the normal liver with 80 kVp. The average score of PET image quality obtained between 80 and 120 kVp was 4.85 ± 0.42 versus 4.90 ± 0.27, respectively (p = 0.47). CONCLUSION: PET/80 kVp CT has no statistically significant difference in the PET image quality and quantitative analysis compared to PET/120 kVp and may be used in selected patients to reduce the radiation dose.

Effect of percutaneous nephrolithotripsy on renal function: assessment with quantitative SPECT of (99m)Tc-DMSA renal scintigraphy.

PURPOSE: To measure the effect of PCNL on global and regional renal function using quantitative single-photon emission CT (SPECT) measurement of Tc-dimercaptosuccinic acid (DMSA) uptake by the kidneys (QDMSA). PATIENTS AND METHODS: A series of 47 male and 41 female patients with a mean age of 47 +/- 16 years were studied by sequential QDMSA examinations before and 1.5 to 24 months after PCNL. Among the 67 patients (76%) in whom PCNL was performed using upper- or lower-pole access, the function of the affected and nonaffected poles of the treated kidney was calculated separately. RESULTS: There was no statistically significant difference in the uptake by the treated kidneys before versus after PCNL (11.9% +/- 5% v 11.6% +/- 5%; t = 0.9; P = 0.368). The total functional volume of the treated kidney was slightly decreased, from 235 cc +/- 62 cc to 224 cc +/- 59 cc (t = 2.7; P = 0.011). The percent of the injected isotope dose per cubic centimeter of tissue of the treated kidney was not affected (0.051 +/- 0.02 v 0.053 +/- 0.02; t = 0.86; P = 0.296). Regional assessment revealed a statistically significant decrease in the functional volume at the PCNL port of entry (91 cc +/- 30 cc v 82 cc +/- 27 cc; t = 2.64; P = 0.013). Regarding the percent of the injected dose per cubic centimeter of renal tissue, no statistically significant difference was found between the area of the kidney that underwent PCNL and the untreated area of the same kidney (0.049 +/- 0.02 v 0.05 +/- 0.02; t = 0.693; P = 0.494). The function of the contralateral kidneys remained unchanged (13.4% +/- 5.2% v 13.6% +/- 4.8%; t = 0.68; P = 0.5). CONCLUSIONS: Despite the statistically significant decrease in the functional volume of the surgically treated region, neither total percent uptake nor percent of injected dose were reduced significantly. Further studies with long-term follow-up of treated kidneys are required.

[Does percutaneous nephrolithotripsy (PCNL) affect renal function: assessment with quantitative spect of Tc 99M-DMSA (QDMSA) renal scintigraphy].

PURPOSE: The study aimed to quantitatively investigate the effect of PCNL on global and regional function using quantitative single photon emission computerized tomography (SPECT) measurement of Tc-dimercaptosuccinic acid (DMSA) uptake by the kidneys (QDMSA). METHODS: Seventy nine patients with nephrolithiasis undergoing PCNL were studied by sequential QDMSA examination. There were 42 (53%) males and 37 (47%) females with mean age of 47 +/- 16 years. The initial study was conducted before PCNL procedure and the follow-up studies were performed 1.5-24 months after PCNL. Among 60 of the 79 (76%) patients, in whom PCNL was performed using upper or lower pole access, regional renal function of affected and non-affected pole of operated kidney was calculated separately. RESULTS: There was no statistically significant difference between the uptake of treated kidney before and after PCNL procedure (11.9% +/- 5% vs 11.6% +/- 5%; t = 0.9, p = 0.368). The total renal functional volume of treated kidney was to be slightly decreased from 235cc +/- 62cc to 224cc +/- 59cc (t = 2.7; p = 0.011). The percent of injected dose per ml.. of renal tissue of treated kidney was not affected statistically (0.051 +/- 0.02 vs 0.053 +/- 0.02; t = 0.86, p = 0.296). In the assessment of the regional renal function of treated kidney, a statistically significant decrease in the functional renal volume was revealed at the part which underwent PCNL procedure (91cc +/- 30cc vs 82cc +/- 27cc; t = 2.64, p = 0.013). Regarding percent of injected dose per ml. of renal tissue, no statistically significant difference was found between the part of treated kidney, which underwent PCNL and non-affected area of the same kidney (0.049 +/- 0.02 vs 0.05 +/- 0.02; t = 0.693, p = 0.494). The function of contralateral kidney remained unchanged (13.4% +/- 5.2% vs 13.6% +/- 4.8%; t = 0.68, p = 0.5). Function volume, neither total percent uptake, nor percent of injected dose per ml. of renal tissue were reduced significantly. Further studies with long term follow-up of treated kidney are required.

The value of 18-FDG PET/CT in the diagnosis and management of implant-related infections of the tibia: a case series.

BACKGROUND: Positron emission tomography (PET) combined with Computerised Tomography (CT) is gaining ground in clinical settings due to its added value of combined metabolic and anatomical imaging. PET/CT has shown promising results in diagnosing both acute and chronic infection of the axial and appendicular skeleton. PET imaging has an advantage in patients with metallic implants because FDG uptake, in contrast to magnetic resonance imaging (MRI) and standard computed tomography (CT), is not hampered by metallic artifacts. The role of PET/CT in the evaluation of implant-related infections involving the tibia in particular has not been thoroughly studied. PURPOSE: To investigate the usefulness of 18-FDG PET/CT in the diagnosis and treatment of implant-related infections of the tibia following osteosynthesis. METHODS: We reviewed 10 patients who underwent internal fixation to the tibia following trauma (4 open fractures, 6 closed fractures) and presented later with clinical signs of a possible implant-related infection. In evaluating the patients we used standard work-up methods (standard radiographs, lab tests) as well as advanced imaging techniques (PET/CT) in order to confirm the diagnosis and decide upon the preferred treatment. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were then calculated for PET/CTs ability to predict presence of infection using intraoperative cultures as the gold standard. RESULTS: PET/CT validated our working diagnosis 9 out of 10 patients. In particular, it helped distinguish between: infected nonunion (n=4), aseptic nonunion (n=1), soft tissue infection (n=2) and chronic osteomyelitis (n=3). The overall sensitivity and specificity of PET/CT for identifying an osseous infection were 85.7% and 100%, respectively. The PPV and NPV were 100% and 75%, respectively. CONCLUSION: PET/CT is a promising imaging modality that can aid in the work up of patients with suspected implant-related infections of the tibia following osteosynthesis, and may be used as a supportive measure in clinical decision making.

The role of FDG-PET/CT imaging in early detection of extra-cardiac complications of infective endocarditis.

The exact incidence of extra-cardiac complications (ECC) in patients with infective endocarditis (IE) is unknown but presumed to be high. These patients, although mostly asymptomatic, may require a more aggressive therapeutic approach. (18)fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is used for the diagnosis of infections, but its role in the early diagnosis of IE complications is still unclear. This study aimed to evaluate the role of FDG-PET/CT in the early diagnosis of ECC in IE and its implications for medical management. We prospectively studied 40 consecutive patients with a confirmed diagnosis of IE (according to the modified Duke criteria) who underwent a whole body FDG-PET/CT study within 14 days from diagnosis. The FDG-PET/CT demonstrated ECC in 17 (42.5%) patients, while 8 (38.1%) of them were asymptomatic. The most frequent embolic sites were musculoskeletal and splenic. Owing to the FDG-PET/CT findings, treatment planning was modified in 14 (35%) patients. This included antibiotic treatment prolongation (27.5%), referral to surgical procedures (15%) and, most substantially, prevention of unnecessary device extraction (17.7%). According to our experiences, FDG-PET/CT imaging was useful in the detection of embolic and metastatic infections in IE. This clinical information had a significant diagnostic and therapeutic impact in managing IE disease.

[18F]FDG-PET/CT for the diagnosis of patients with fever of unknown origin.

BACKGROUND AND AIMS: The diagnosis of patients with fever of unknown origin (FUO) remains a challenging medical problem. We aimed to assess the diagnostic contribution of 18-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET)/computed tomography (CT) for the evaluation of FUO. METHODS: We performed a 4-year retrospective single-center study of all hospitalized patients that underwent FDG-PET/CT for evaluation of FUO. The final diagnosis of the febrile disease was based on clinical, microbiological, radiological and pathological data available at the final follow-up. Predictors for a contributory exam were sought. RESULTS: One hundred and twelve patients underwent FDG-PET/CT for the investigation of FUO in the years 2008-2012 and were included in the study. A final diagnosis was determined in 83 patients (74%) and included: infectious disease in 49 patients (43%), non-infectious inflammatory disease in 17 patients (16%), malignancies in 15 patients (14%), other diagnoses in 2 patients (1.7%), FUO resolved with no diagnosis and no evidence of disease during a 6-month follow-up in 23 patients (20%), and death with fever and with no diagnosis in 6 patients (5%). Seventy-four FDG-PET/CT studies (66%) were considered clinically helpful and contributory to diagnosis (46% positive contributory value and 20.5% contributory to exclusion of diagnosis). PET/CT had a sensitivity of 72.2%, a specificity of 57.5%, a positive predictive value (PPV) of 74.2% and a negative predictive value (NPV) of 53.5%. On multivariable analysis, significant predictors of a positive PET/CT contributory to diagnosis were a short duration of fever and male gender. CONCLUSIONS: PET/CT is an important diagnostic tool for patients with FUO.

Quantitative SPECT uptake of 99mTc-dimercaptosuccinic acid by the kidneys in children.

UNLABELLED: The normal range of values for quantitative SPECT of 99mTc-dimercaptosuccinic acid (DMSA) uptake by the kidneys in children was studied. METHODS: Renal functioning volume, percentage of injected dose per cubic centimeter of renal tissue (%ID/ cm3) and individual kidney uptake of 270 kidneys performed on 135 children, aged 2 wk-15 y, provided the basic data for this study. The accrual was part of the work-up of children with urinary tract infection where no structural or functional abnormalities of the renal tract could be established. Children were grouped according to age intervals, and a distribution chart was obtained with 2 SD above and below the mean of the values obtained for volume (%ID/cm3) and kidney uptake in each age group. RESULTS: A significant correlation was found between age and functional volume (r = 0.90; 95% confidence interval [CI], 0.88-0.92; P = 0.000), and a significant inverse correlation was found between age and %ID/cm3 (r = -0.86; 95% CI, -0.88 to -0.82; P = 0.000). No statistically significant correlation was found between age and kidney uptake (r = -0.20; 95% CI, -0.32 to -0.09; P = 0.001). CONCLUSION: It seems that the normal maturational changes in renal function observed in infants and newborns do not affect the kidney uptake of 99mTC-DMSA. Thus, quantitation of 99mTc-DMSA uptake by the kidneys can be used to assess changes in the individual renal function over time in this age group.

Radionuclide assessment of penile corporal venous leak using technetium-99m-labeled red blood cells.

In an attempt to evaluate penile corporal venous outflow, a method that utilizes intracorporal injection of Tc-RBC was developed and used in 20 patients with erectile dysfunction. Seven patients showed venous leak and 13 had normal venous outflow. Technetium-labeled RBC corporal clearance in the flaccid state and after intracorporal injection of papaverine (30 mg) and regitine (1 mg) were assessed in sequence by two separate injections of 18.5 MBq of Tc-RBC each. The time for 50% corporal clearance (T50%) was determined from the time activity curves obtained in flaccid state and after intracorporal injection of the vasoactive agent. There were no statistically significant differences in T50% measured in the flaccid state between normal venous outflow (202 +/- 139 sec) and venous leak (92 +/- 35 sec, p = 0.1). However, after intracorporal injection of papaverine and regitine a significant increase in the T50% was noted in normal venous outflow (2892 +/- 1899 sec) as compared to venous leak (213 +/- 123 sec, p less than 0.001). The results suggest that measurement of corporal clearance of Tc-RBC after intracorporal injection of papaverine may be a useful method in detecting venous leak, and could be used as a screening test in patients with erectile dysfunction.

Renal function and technetium-99m-dimercaptosuccinic acid uptake in single kidneys: the value of in vivo SPECT quantitation.

The ability to evaluate kidney function in each kidney separately by quantitative SPECT was tested in 20 patients with a single kidney and varying degrees of renal disease. Technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) uptake was compared with renal function measured by creatinine clearance and serum creatinine. There was a good correlation for both serum creatinine (r = 0.89, y = 24.6 *X -1.15, error = 5.6, p less than 0.001) and creatinine clearance (r = 0.76, y = 0.6 *X 0.84, error = 8.0, p less than 0.001). The results indicate that SPECT quantitation of 99mTc-DMSA uptake can be used as an indicator of the function of each kidney individually.

Quantitative SPECT of 99mTc-DMSA uptake in kidneys of infants with unilateral ureteropelvic junction obstruction: assessment of structural and functional abnormalities.

UNLABELLED: We evaluated individual renal function using quantitative SPECT of dimercaptosuccinic acid (DMSA) uptake by the kidneys (QDMSA) in infants with unilateral ureteropelvic junction (UPJ) obstruction and compared our findings with infants without obstruction. METHODS: QDMSA was performed on 13 infants (mean age of 2.8 +/- 2.8 mo) with unilateral UPJ obstruction and on 15 age-matched controls without obstruction. RESULTS: Control kidneys (n = 30) had a volume of 43.5 +/- 8.8 mL, a percentage injected dose (%ID)/mL 0.62 +/- 0.12 and uptake of 26.1% +/- 3.9%. Kidneys with UPJ obstruction (n = 13) had a volume of 61.2 +/- 19.3 mL, a %ID/mL of 0.42 +/- 0.11 and uptake of 25.4% +/- 8.2%. Contralateral kidneys (n = 13) had a volume of 44.0 +/- 11.9 mL, a %ID/mL of 0.57 +/- 0.16 and uptake of 24.2% +/- 4.6%. The uptake in obstructed kidneys was similar to that observed in contralateral and control kidneys (t = -0.77, P = 0.45; t = -0.37, P = 0.71; respectively). UPJ kidneys had a statistically significant increased volume and decreased %ID/mL, compared with contralateral kidneys (t = 3.35, P < 0.006 and t = 3.75, P < 0.003, respectively) and control kidneys (t = -4.2, P < 0.001 and t = 4.7, P < 0.001, respectively). There was no significant difference between contralateral kidneys and control kidneys regarding volume (t = -0.16, P = 0.87), %ID/mL (t = 0.98, P = 0.33) and uptake (t = -1.41, P = 0.16). Of 13 infants, 11 (85%) showed large kidneys with thinning of the renal cortex. In 1 infant, there was no difference between the obstructed and contralateral kidneys regarding volume, %ID/mL and uptake, and 1 infant showed significant decreased uptake in the UPJ kidney compared with the contralateral kidney. CONCLUSION: Although the overall renal function of the obstructed kidneys remained unchanged, there was a statistically significant decrease in the %ID/mL of renal tissue in UPJ kidneys, which may represent renal dysfunction. Increased functional volume with a thin cortex may represent a compensatory mechanism of the obstructed kidney. Such changes may contribute to the understanding of pathophysiologic mechanisms and may be an early sign of obstruction in infants with hydronephrosis. Further longitudinal studies with an extended number of infants and serial measurements of kidney volumes and %ID/mL are warranted to assess the significance of QDMSA in the management of infants with asymptomatic unilateral renal pelvic dilatation.

Renal function after tumor enucleation: assessment by quantitative SPECT of 99mTc-dimercaptosuccinic acid uptake by the kidneys.

UNLABELLED: The purpose of this study was to evaluate the amount of functioning renal mass removed and the amount of remaining individual renal function after tumor enucleation. METHODS: Renal functional volume, percentage injected dose (%ID) per cubic centimeter of renal tissue and individual renal uptake of 24 operated and 24 contralateral kidneys were studied by two sequential SPECT quantitations of 99mTc-dimercaptosuccinic acid (DMSA) uptake by the kidneys (QDMSA). The first study was before surgery and the second study was 1 to 6 mo (mean 3.5 mo) after surgery. Mean tumor size was 3.4 +/- 0.99 cm and all tumors were confined to the renal parenchyma (stages pT1 and pT2). RESULTS: In the operated kidneys, there was a statistically significant decrease in renal cortical volume (170 +/- 46 mL after surgery versus 207 +/- 45 mL before surgery, t = 6.2, P < 0.001) and individual renal uptake (10.3% +/- 3.0% after surgery versus 13.0% +/- 2.9% before surgery, t = 5.4, P < 0.001). There was no statistically significant change after surgery compared with before surgery in the %ID per cubic centimeter of renal tissue of the operated kidneys, and in the volume, %ID per cubic centimeter and uptake of the contralateral normal kidneys. CONCLUSION: The results suggest that QDMSA is a noninvasive method able to assess changes in separate renal function. The limited functioning parenchymal loss after tumor enucleation had no effect on the opposite kidneys.

Quantitation of renal uptake of technetium-99m DMSA using SPECT.

Quantitative single photon emission computed tomography (SPECT) methodology based on calibration with kidney phantoms has been applied for the assessment of renal uptake of [99mTc]DMSA in 25 normals; 16 patients with a single normal kidney; 30 patients with unilateral nephropathy; and 17 patients with bilateral nephropathy. An excellent correlation (r = 0.99, s.e.e. = 152) was found between SPECT measured concentration and actual concentration in kidney phantoms. Kidney uptake at 6 hr after injection in normals was 20.0% +/- 4.6% for the left and 20.8% +/- 4.4% for the right. Patients with unilateral nephropathy had a statistically significant (p less than 0.001) low uptake in the diseased kidney (7.0% +/- 4.7%), but the contralateral kidney uptake did not differ from the normal group (20.0% +/- 7.0%). The method was especially useful in patients with bilateral nephropathy. Significantly (p less than 0.001) decreased uptake was found in both kidneys (5.1% +/- 3.4% for the left and 6.7% +/- 4.2% for the right). The total kidney uptake (right and left) in this group showed to be inversely correlated (r = 0.83) with serum creatinine. The uptake of [99mTc]DMSA in single normal kidney was higher (p less than 0.001) than in a normal kidney (34.7% +/- 11.9%), however, it was lower than the total absolute uptake (RT + LT = 41.5% +/- 8.8%) in the normal group. The results indicate that SPECT is a reliable and reproducible technique to quantitate absolute kidney uptake of [99mTc]DMSA.

Stress fractures associated with osteosarcoma of the lower limb.

Three patients with osteosarcoma of the femur developed abnormal radiopharmaceutical uptake in the bones of the contralateral leg. This uptake was not due to metastases. The histology in one patient, the form of the lesion and the disappearance of the abnormal uptake without treatment in the other two, indicated that the uptake was probably due to stress fractures. Changes in weight bearing and walking in the normal leg as a result of the osteosarcoma in the other leg could have been the cause of the stress fractures. It should be recognized that new abnormal uptake on bone scintigraphy in patients with osteosarcoma of the leg may not necessarily indicate metastasis. It may be caused by a stress fracture and disappears after rest.

Scintigraphy of posterior tibial tendinitis.

UNLABELLED: Our goal was to describe the typical scintigraphic pattern of posterior tibial tendinitis. METHODS: Bone scintigraphs were reviewed to study the scintigraphic characteristics of posterior tibial tendinitis in nine patients with posterior tibial tendinitis related to generalized rheumatic disease and in eight patients with isolated posterior tibial tendinitis. RESULTS: The scintigraphic pattern of posterior tibial tendinitis is elongated increased uptake in the blood flow and blood-pool phase along the anatomical course of the tibialis posterior tendon at the medial aspect of the ankle (malleolus region). Static images demonstrate increased focal abnormal uptake at the medial malleolus and in the navicular bone. CONCLUSION: Bone scintigraphy depicts a characteristic pattern of posterior tibial tendinitis. It is useful for the early diagnosis of idiopathic- or rheumatic-related posterior tibial tendinitis.

Quantitative SPECT of technetium-99m-DMSA uptake in the kidneys of normal children and in kidneys with vesicoureteral reflux: detection of unilateral kidney disease.

UNLABELLED: Quantitative SPECT was used to evaluate renal functional volume (cc), percent of injected dose/cc (%ID/cc) and renal uptake (%) in 11 children with unilateral vesicoureteral reflux grade 3 or greater, and in 19 normal control children without reflux. METHODS: Studies were performed 4-6 hr after intravenous injection of 0.750-2 mCi of 99mTc-DMSA. RESULTS: Control kidneys (n = 38) had a volume of 99.7 +/- 29.5 cc. The %ID/cc was 0.27 +/- 0.08, and the uptake in one kidney was 24.8% +/- 3.9%. Global renal uptake (right plus left) was 49.6% +/- 7.3%. Functional volume of the control kidneys showed an increase with age, and the %ID/cc showed a steeper decrease with age, resulting in a trend of the kidney uptake to decrease with age. Kidneys with reflux had a decreased kidney uptake of 15.7% +/- 29.5%, compared to age- and sex-matched controls (t = 4.7, p < 0.001). The contralateral kidneys without reflux had a significantly increased total uptake of 33.4% +/- 6.8% as compared to controls (t = 3.44, p < 0.01). Global uptake by the kidneys was 49.2% +/- 8.6% and was not statistically different from controls (t = 1.0, ns). CONCLUSION: Our results suggest that SPECT quantitation of 99mTc-DMSA uptake in each kidney separately could be used as a noninvasive method to assess impairment and compensation of the function of the individual kidney in children with vesicoureteral reflux.

Kidney function after radical nephrectomy: assessment by quantitative SPECT of 99mTc-DMSA uptake by the kidneys.

UNLABELLED: To determine the function of the remaining contralateral kidney after the removal of a functioning kidney, 30 consecutive patients (18 men, 12 women; average age, 67 y; age range, 34-87 y) who were undergoing unilateral radical nephrectomy were evaluated by sequential quantitative 99mTc-dimercaptosuccinic acid (DMSA) SPECT (QDMSA) studies. METHODS: The 30 patients were undergoing radical nephrectomy for renal tumors. The first study was done before surgery. Follow-up studies were performed 2-23 mo after surgery. Clinical evaluations and determinations of serum creatinine level were performed at the same time as the QDMSA studies. RESULTS: The relative contribution of the resected kidneys to the global renal function before surgery was 43.2% +/- 7.3%. After surgery the uptake of the remaining kidney increased from 13.4% +/- 4.0% to 18.3% +/- 5.8% (t = 5.7; P = 0.0000). The relative function of the remaining kidney increased from 56.8% +/- 7.1% to 79.1% +/- 23.6% (t = 4.9; P < 0.0001) of the global renal function before nephrectomy. Increases in the renal volume (from 211 +/- 62 cm3 to 229 +/- 68 cm3; t = 4.5; P = 0.0001) and in the percentage injected dose per cubic centimeter (%ID/cm3) of the remaining kidney (from 0.066 +/- 0.02 % ID/cm3 to 0.085 +/- 0.03 %ID/cm3; t = 4.6; P = 0.0001) were associated with this change. Nine patients had 2 follow-up studies performed 3-4 mo after surgery and 12-14 mo after surgery. The volume of the remaining kidney (209.22 +/- 46.20 cm3 versus 217.88 +/- 58.85 cm3; t = 0.962; P = 0.364), the %ID/cm3 (0.09 +/- 0.016 %ID/cm3 versus 0.093 +/- 0.025 %ID/cm3; t = 0.362; P = 0.726), and the percentage uptake (19.26% +/- 4.45% versus 20.11% +/- 7.01%) did not change significantly between these 2 QDMSA studies. CONCLUSION: The results of this study suggest that adaptive changes causing hyperfunction of the remaining kidney may occur after nephrectomy of a functioning kidney in adults. These changes occur soon after surgery, persist for at least 1 y, and are evident on QDMSA studies.