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.

Double-pionic fusion of nuclear systems and the "ABC" effect: approaching a puzzle by exclusive and kinematically complete measurements.

The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn-->dpi;{0}pi;{0} at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (pipi)_{I=L=0} channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a DeltaDelta system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.

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.

Bilateral distal tibial osteochondral lesion: a case report.

Osteochondral lesion of the talar dome is a well-known clinical and radiographic entity. Less known is osteochondral lesion of the articular surface of the distal tibia. A case report, which demonstrates bone-scintigraphy and MRI findings of bilateral osteochondral lesion of tibial plafond and related literature, is presented.

How accurate is helical CT volumetric assessment in renal tumors?

The aim of this study was to evaluate the accuracy of tumor size measurement on CT studies of renal tumors. Sixteen patients with tumors of the kidneys were imaged by helical CT prior to surgery. Assessment of tumor volume was made by two radiologists on the CT images with the summation of area method, then compared with the resected specimen water displacement volume. Intra- and interobserver agreement for CT measurements were also assessed. There were substantial differences between the CT volume measurement compared with the tumor post-operative volume (mean of differences 30.05+/-91.6, 95%CI: 31.45-91.55). The inter- and intraobservation agreements for tumor measurement by CT was found to be satisfactory (ANOVA: p < 0.0001; t-test: p < 0.05). The CT volumetric measurement by area summation is a method with good inter- and intraexamination reproducibility but not an accurate technique for tumor volume assessment.

Stress-induced osteolysis of distal clavicle: imaging patterns and treatment using CT-guided injection.

Osteolysis of distal clavicle (ODC) may occur in patients who experience repeated stress or microtrauma to the shoulder. This entity has clinical and radiological findings similar to post-traumatic ODC. We describe a case of successful treatment of stress-induced ODC with CT-guided injection of corticosteroid and anesthetic drug into the acromioclavicular joint.

Bone scintigraphic findings of os trigonum: a prospective study of 100 soldiers on active duty.

PURPOSE: To determine the clinical significance of an increased uptake of 99mTc methylene-diphosphonate (Tc-MDP) in the os trigonum region seen on bone scintigrams of soldiers on active duty. PATIENTS AND METHODS: Radionuclide whole-body skeletal imaging and physical examination of the foot were carried out in 100 consecutive soldiers on active duty referred for evaluation of suspected stress-injury of the lower limbs, back pain, and different skeletal trauma. Lateral radiographs of the foot were performed in those with increased uptake of Tc-MDP at the site of os trigonum. Radiographic, scintigraphic, and clinical findings were correlated. RESULTS: Among 200 feet, 27 (13.5%) showed an increased uptake of Tc-MDP in the os trigonum region. The right side was affected in six patients, the left side in 11 and five patients had bilaterally increased uptake. On X-rays, 31 of 44 feet showed the os trigonum. Only 10 of these 27 feet (37%) had a symptomatic os trigonum. CONCLUSIONS: Our results suggest that increased uptake of Tc-MDP in the os trigonum region is a frequent finding among active soldiers and is of limited value in detecting symptomatic os trigonum.

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.