123I-hippuran renal scintigraphy with evaluation of single-kidney clearance for predicting renal scarring after acute urinary tract infection: comparison with (99m)Tc-DMSA scanning.

The value of (123)I-hippuran (OIH) renal sequential scintigraphy (RSS) in predicting the evolution of defects detected by (99m)Tc-dimercaptosuccinic acid (DMSA) scanning during a first episode of acute pyelonephritis (APN) was assessed. METHODS: Fifty-eight children with APN underwent (99m)Tc-DMSA planar scanning and (123)I-OIH RSS during acute infection and at least 5 mo later. Renal lesions found by (99m)Tc-DMSA scanning were classified according to the following (99m)Tc-DMSA grading system: 0 = normal, 1 = 1 lesion, 2 = 2 lesions, and 3 = diffuse damage with renal parenchymal subversion. Renal scarring was diagnosed whenever a renal cortical defect detected at the first (99m)Tc-DMSA examination persisted on the follow-up (99m)Tc-DMSA examination. Single-kidney clearance rate (Cl) was evaluated by a method that was previously validated at our institution and is based on time-activity curves measured on the heart and kidney areas by the region-of-interest technique. RESULTS: (99m)Tc-DMSA scanning showed renal damage in 76 kidneys and had negative findings for the remaining 40 kidneys (2 patients had bilaterally negative findings). (99m)Tc-DMSA scanning determined 40 kidneys to be grade 0, 49 to be grade 1, 21 to be grade 2, and 6 to be grade 3. For (99m)Tc-DMSA grades of 0-3, the corresponding Cl mean values (in mL/min/1.73 m(2) of body surface area [BSA]) were 292 +/- 33, 237 +/- 39, 210 +/- 54, and 140 +/- 53, respectively. The Spearman regression coefficient (R) demonstrated a significant correlation between (99m)Tc-DMSA grade and Cl (R = 0.69, P < 0.0001). Thirty-six of the lesions detected by staging (99m)Tc-DMSA were shown to have recovered on follow-up renal scans, whereas 40 developed scars. A significant difference in Cl was found between the 2 groups (P < 0.0002). The Cl cutoff value was determined by univariate discriminant analysis; a Cl value of 232 mL/min/1.73 m(2) of BSA discriminated best between scarred and nonscarred kidneys, with a specificity, sensitivity, positive predictive value, negative predictive value, and overall accuracy of 95%, 95%, 90%, 97%, and 95%, respectively. CONCLUSION: Cl evaluation, in the course of acute urinary tract infection, is highly valuable in predicting the fibrotic evolution of renal damage detected on acute (99m)Tc-DMSA scanning. Also, our data show close agreement between Cl and the grade determined by staging (99m)Tc-DMSA.     

Tc-99m exametazime-labeled leukocyte scans in the study of infections in skull neurosurgery

Diagnosis and follow-up of skull infections are usually performed by neurologic examination, laboratory tests and instrumental diagnostic methods such as computed tomography (CT) and magnetic resonance imaging (MRI). These have, however, shown some limitations for specificity. The aim of the current study was to evaluate the overall contribution of Tc-99m exametazime-labeled leukocyte imaging scan Tc-99m hexamethylpropyleneamine (HMPAO) labeled white blood cells (WBC) in the diagnosis and management of infections in skull neurosurgery. Thirty-four patients were subdivided into 4 groups on the basis of the suspected pathology: intracerebral lesions on CT or MRI (group A, n = 20), suspected postsurgical infections (group B, n = 6), suspected deep infection of the surgical wound (group C, n = 4), and suspected infection of the ventriculoperitoneal shunt (group D, n = 4). All patients underwent CT, MRI, and Tc-99m HMPAO WBC imaging. Patients in group C also underwent bacteriologic and culture examinations of wound secretions if present. In positive cases in group A, Tc-99m HMPAO WBC imaging was repeated. The scintigraphic results were compared with histologic findings in patients who underwent surgery and with the results of a 12-month clinical follow-up in the remaining patients. Tc-99m HMPAO WBC scans correctly detected the infections in all groups. Furthermore, such imaging proved to be able to document recovery from the disease in all of the assessed cerebral abscesses. This study may have an important role both in the diagnosis and in the management of infections in skull neurosurgery, which, it is hoped, will be confirmed in the future.     

Posterior reversible encephalopathy syndrome: do predisposing risk factors make a difference in MRI appearance?

Introduction  Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity, characterized by typical neurological deficits, distinctive magnetic resonance imaging (MRI) features, and a usually benign clinical course. Although frequently seen in association with hypertensive conditions, many other predisposing factors, notably cytotoxic and immunosuppressant drugs have been associated with PRES. The aim of this study was to determine differences in the MR appearance of PRES according to various risk factors. Methods  Thirty consecutive patients with clinical and MRI findings consistent with PRES were included. We identified 24 patients with hypertension-related conditions, including 14 patients with preeclampsia–eclampsia, and six patients without hypertension, in whom PRES was associated with exposition to neurotoxic substances. Lesion distribution, extent of disease, and number of affected brain regions were compared between patients with PRES with and without hypertension, and patients with PRES with and without preeclampsia–eclampsia, respectively. Results  No statistically significant differences in distribution of lesions and extent of disease were observed between patients with PRES with or without hypertension, and patients with or without preeclampsia–eclampsia, respectively. The number of affected brain regions was significantly higher in patients with preeclampsia–eclampsia (p = 0.046), and the basal ganglia region was more frequently involved in these patients (p = 0.066). Conclusion  Apart from a significant higher number of involved brain regions and a tendency for basal ganglia involvement in patients with PRES associated with preeclampsia–eclampsia, the MRI appearance of patients with PRES does not seem to be influenced by predisposing risk factors.     

Wound ballistic evaluation of the TASER® XREP ammunition

The Taser® eXtended Range Electronic Projectile (XREP®) is a wireless conducted electrical weapon (CEW) designed to incapacitate a person from a larger distance. The aim of this study was to analyze the ballistic injury potential of the XREP. Twenty rounds were fired from the Taser®X12 TM shotgun into ballistic soap covered with artificial skin and clothing at different shooting distances (1–25 m). One shot was fired at pig skin at a shooting distance of 10 m. The average projectile velocity was 67.0 m/s. The kinetic energy levels on impact varied from 28–52 J. Depending on the intermediate target, the projectiles penetrated up to 4.2 cm into the ballistic soap. On impact the nose assembly did not separate from the chassis, and no electrical activation was registered. Upon impact, a skin penetration of the XREP cannot be excluded. However, it is very unlikely at shooting distances of 10 m or more. Clothing and a high elasticity limit of the target body area can significantly reduce the penetration risk on impact.     

Dual-energy CT: a phantom comparison of different platforms for abdominal imaging

Objectives

Evaluation of imaging performance across dual-energy CT (DECT) platforms, including dual-layer CT (DLCT), rapid-kVp-switching CT (KVSCT) and dual-source CT (DSCT).

Methods

A semi-anthropomorphic abdomen phantom was imaged on these DECT systems. Scans were repeated three times for CTDIvol levels of 10 mGy, 20 mGy, 30 mGy and different fat-simulating extension rings. Over the available range of virtual-monoenergetic images (VMI), noise as well as quantitative accuracy of hounsfield units (HU) and iodine concentrations were evaluated.

Results

For all VMI levels, HU values could be determined with high accuracy compared to theoretical values. For KVSCT and DSCT, a noise increase was observed towards lower VMI levels. A patient-size dependent increase in the uncertainty of quantitative iodine concentrations is observed for all platforms. For a medium patient size the iodine concentration root-mean-square deviation at 20 mGy is 0.17 mg/ml (DLCT), 0.30 mg/ml (KVSCT) and 0.77mg/ml (DSCT).

Conclusion

Noticeable performance differences are observed between investigated DECT systems. Iodine concentrations and VMI HUs are accurately determined across all DECT systems. KVSCT and DLCT deliver slightly more accurate iodine concentration values than DSCT for investigated scenarios. In DLCT, low-noise and high-image contrast at low VMI levels may help to increase diagnostic information in abdominal CT.

Key Points

? Current dual-energy CT platforms provide accurate, reliable quantitative information. ? Dual-energy CT cross-platform evaluation revealed noticeable performance differences between different systems. ? Dual-layer CT offers constant noise levels over the complete energy range.

     

<Emphasis Type="Italic">V</Emphasis>O<Subscript>2Max</Subscript> and <Emphasis Type="Italic">V</Emphasis>O<Subscript>2AT</Subscript>: athletic performance and field role of elite soccer players

Purpose

Maximal oxygen consumption (VO_2max) and oxygen consumption at anaerobic threshold (VO_2AT) are commonly measured parameters to test elite soccer players; however, studies relating metabolic parameters of professional soccer players with performance and best fitting to the field role are scarce. Our aim was to study the relations of VO_2max and VO_2AT with the field role of elite soccer players to generate a robust dataset with a solid statistical analysis.

Method

Over a 12-year period we performed 953 field evaluation tests of VO_{2 max} and VO_2AT on 450 elite soccer players of 13 professional teams by incremental, continuous and exhausting test modified from Conconi’s test. Statistical analysis was performed by one-way ANOVA followed—when appropriate—by Tukey post hoc test. Effect size was evaluated by the Cohen D test and η partial squared test. Statistical significance was set for p < 0.05.

Results

VO_2max mean values increased at the beginning of season by 1.073 ± 0.06 respect to pre-season then decreased again up to pre-season levels and remained stable, while VO_2AT did not change during time. VO_2max differences were also related to players’ field role. VO_2max mean value for Goalkeeper was 50.85 ± 4.2, for central Defender was 57.58 ± 4.3, for Winger-sides back was 60.53 ± 5.02, for Midfielder was 59.53 ± 5.08, for Forward was 56.52 ± 4.14. On the contrary, as expected, VO_2AT percentage variations among the roles were not significant.

Conclusions

VO_2max is the choice parameter to consider for the metabolic compliance of athletes to the field role requirements, consequently influencing training programs, recovery and injury prevention strategies.

     

Local staging of rectal cancer: assessment with double-contrast multislice computed tomography and transrectal ultrasound

OBJECTIVE: The aim of this study was to evaluate the accuracy of multislice computed tomography (MSCT) with double-contrast technique and transrectal ultrasound (TRUS) in staging of rectal carcinoma compared with histopathological confirmation. METHODS: In a prospective study of 92 patients with rectal carcinoma, preoperative MSCT with negative rectal contrast (methylcellulose) and intravenous contrast was performed. Reconstructions in 3 planes were analyzed in a cine mode in picture archiving and communication (PAC) system. Analysis of rectal wall infiltration was performed preoperatively according to a modified tumor, nodes, metastases (TNM)-classification system (< or =T2/T3/T4, N0/N+, UICC/UICC I > I). MSCT imaging findings were compared with the results of TRUS and histopathology in all patients. RESULTS: With interactive multiplanar image viewing, the results of MSCT of depth of rectal wall invasion (T-staging) were as follows: sensitivity, specificity, positive and negative predictive values, and accuracy rate were 85%, 87%, 88%, 84%, and 86% (54/63 patients) compared with 59%, 63%, 72%, 48%, and 60% (38/63 patients), respectively, for TRUS staging in the same patients. The sensitivity, specificity, positive and negative predictive values, and accuracy rate of MSCT for perirectal nodes evaluation was 75%, 85%, 75%, 85%, and 81% (51/63 patients) compared with 55%, 71%, 50%, 74%, and 65% (41/63 patients), respectively, for TRUS in detecting metastatic lymph nodes. CONCLUSIONS: Preoperative double-contrast MSCT accurately indicates the exact depth of tumor infiltration and improves lymph node staging. The new technical innovations of MSCT provide superior information for preoperative staging of rectal cancer and may compete with TRUS as the standard preoperative diagnostic method.     

Quantitative CT detects progression in COPD patients with severe emphysema in a 3-month interval

Chronic obstructive pulmonary disease (COPD) is characterized by variable contributions of emphysema and airway disease on computed tomography (CT), and still little is known on their temporal evolution. We hypothesized that quantitative CT (QCT) is able to detect short-time changes in a cohort of patients with very severe COPD. Two paired in- and expiratory CT each from 70 patients with avg. GOLD stage of 3.6 (mean age = 66 ± 7.5, mean FEV1/FVC = 35.28 ± 7.75) were taken 3 months apart and analyzed by fully automatic software computing emphysema (emphysema index (EI), mean lung density (MLD)), air-trapping (ratio expiration to inspiration of mean lung attenuation (E/I MLA), relative volume change between − 856 HU and − 950 HU (RVC856–950)), and parametric response mapping (PRM) parameters for each lobe separately and the whole lung. Airway metrics measured were wall thickness (WT) and lumen area (LA) for each airway generation and the whole lung. The average of the emphysema parameters (EI, MLD) increased significantly by 1.5% (p < 0.001) for the whole lung, whereas air-trapping parameters (E/I MLA, RVC856–950) were stable. PRMEmph increased from 34.3 to 35.7% (p < 0.001), whereas PRMNormal decrased from 23.6% to 22.8% (p = 0.012). WT decreased significantly from 1.17 ± 0.18 to 1.14 ± 0.19 mm (p = 0.036) and LA increased significantly from 25.08 ± 4.49 to 25.84 ± 4.87 mm2 (p = 0.041) for the whole lung. The generation-based analysis showed heterogeneous results. QCT detects short-time progression of emphysema in severe COPD. The changes were partly different among lung lobes and airway generations, indicating that QCT is useful to address the heterogeneity of COPD progression. • QCT detects short-time progression of emphysema in severe COPD in a 3-month period. • QCT is able to quantify even slight parenchymal changes, which were not detected by spirometry. • QCT is able to address the heterogeneity of COPD, revealing inconsistent changes individual lung lobes and airway generations.