Imaging Characteristics of Stage I Non-Small Cell Lung Cancer on CT and FDG-PET: Relationship with Epidermal Growth Factor Receptor Protein Expression Status and Survival

Objective

To identify CT and FDG-PET features associated with epidermal growth factor receptor (EGFR) protein overexpression, and to evaluate whether imaging features and EGFR-overexpression can help predict clinical outcome.

Materials and Methods

In 214 patients (M : F = 129 : 85; mean age, 63.2) who underwent curative resection of stage I non-small cell lung cancer, EGFR protein expression status was determined through immunohistochemical analysis. Imaging characteristics on CT and FDG-PET was assessed in relation to EGFR-overexpression. Imaging features and EGFR-overexpression were also evaluated for clinical outcome by using the Cox proportional hazards model.

Results

EGFR-overexpression was found in 51 patients (23.8%). It was significantly more frequent in tumors with an SUV_max > 5.0 (p < 0.0001), diameter > 2.43 cm (p < 0.0001), and with ground glass opacity ≤ 50% (p = 0.0073). SUV_max > 5.0 (OR, 3.113; 95% CI, 1.375-7.049; p = 0.006) and diameter > 2.43 cm (OR, 2.799; 95% CI, 1.285-6.095; p = 0.010) were independent predictors of EGFR overexpression. Multivariate analysis showed that SUV_max > 4.0 (hazard ratio, 10.660; 95% CI, 1.370-82.966; p = 0.024), and the presence of cavitation within a tumor (hazard ratio, 3.122; 95% CI, 1.143-8.532; p = 0.026) were factors associated with poor prognosis.

Conclusion

EGFR-overexpression is associated with high SUV_max, large tumor diameter, and small GGO proportion. CT and FDG-PET findings, which are closely related to EGFR overexpression, can be valuable in the prediction of clinical outcome.     

11C-Acetate as a new biomarker for PET/CT in patients with multiple myeloma: initial staging and postinduction response assessment

Purpose

We investigated the potential value of ¹¹C-acetate (ACT) PET/CT in characterizing multiple myeloma (MM) compared with ¹⁸F-FDG PET/CT. Bone marrow histological and whole-body (WB) MRI findings served as the reference standards.

Methods

In this prospective study, 15 untreated MM patients (10 men and 5 women, age range 48?69 years) underwent dual-tracer ¹¹C-ACT and ¹⁸F-FDG PET/CT and WB MRI for pretreatment staging, and 13 of them had repeated examinations after induction therapy. Diffuse and focal bone marrow uptake was assessed by visual and quantitative analyses, including measurement of the maximum standardized uptake value (SUV_max). Between-group differences and correlations were assessed with the Mann-Whitney U test and the Pearson test.

Results

At staging, all 15 patients had diffuse myeloma involvement upon bone marrow examination with 30–90 % of plasma cell infiltrates. Diffuse infiltration was detected in all of them (100 %) using ¹¹C-ACT with a positive correlation between bone marrow uptake values and percentages of plasma cell infiltrates (r = +0.63, p?=?0.01). In contrast, a diagnosis of diffuse infiltration could be established using ¹⁸F-FDG in only six patients (40 %). Focal lesions were shown in 13 patients on both ¹¹C-ACT PET/CT and WB MRI, and in 10 patients on ¹⁸F-FDG PET/CT. Focal lesions demonstrated ¹¹C-ACT uptake with a mean SUV_max of 11.4 ± 3.3 (range 4.6?19.6, n?=?59), which was significantly higher than the ¹⁸F-FDG uptake (mean SUV_max 6.6 ± 3.1, range 2.3?13.7, n?=?29; p?<?0.0001). After treatment, the diffuse bone marrow ¹¹C-ACT uptake showed a mean SUV_max reduction of 66 % in patients with at least a very good partial response versus 34 % in those with at most a partial response only (p?=?0.01).

Conclusion

PET/CT using ¹¹C-ACT as a biomarker showed a higher detection rate for both diffuse and focal myeloma lesions at diagnosis than using ¹⁸F-FDG, and may be valuable for response assessment.     

Magnetic resonance perfusion and diffusion imaging characteristics of transient bone marrow edema,avascular necrosis and subchondral insufficiency fractures of the proximal femur

Purpose

To evaluate magnetic resonance (MR) perfusion and diffusion imaging characteristics in patients with transient bone marrow edema (TBME), avascular necrosis (AVN), or subchondral insufficiency fractures (SIF) of the proximal femur.

Materials and methods

29 patients with painful hip and bone marrow edema pattern of the proximal femur on non-contrast MR imaging were examined using diffusion-weighted and dynamic gadolinium-enhanced sequences. Apparent diffusion coefficients (ADCs) and perfusion parameters were calculated for different regions of the proximal femur. Regional distribution and differences in ADC values and perfusion parameters were evaluated.

Results

Seven patients presented with TBME, 15 with AVN and seven with SIF of the proximal femur. Perfusion imaging showed significant differences for maximum enhancement values (E_max), slope (E_slope) and time to peak (TTP) between the three patient groups (p < 0.05). In contrast, no significant differences for ADC values were calculated when comparing TBME, AVN, and SIF patients.

Conclusion

Diffusion weighted imaging of bone marrow of the proximal femur did not show significant differences between patients with TBME, AVN or SIF. In contrast, MR perfusion imaging demonstrated significant differences for the different patient groups and may as a complementary imaging technique add information to the understanding of the pathophysiology of diseases associated with bone marrow edema.     

Contrast-Enhanced Harmonic Ultrasonography for the Assessment of Prostate Cancer Aggressiveness: a Preliminary Study

Objective

To determine whether contrast-enhanced harmonic ultrasonography can be used to predict the aggressiveness of prostate cancer.

Materials and Methods

Contrast-enhanced harmonic ultrasonography was performed in 103 patients suspected of prostate cancer before biopsy. Time intensity curves were reconstructed for systematic biopsy sites and sonographic abnormalities. The characteristics of the curves were described using hemodynamic indices including arrival time (AT), time-to-peak (TTP), and peak intensity (PI). The differences of hemodynamic indices between high-grade and low-grade cancer were analyzed and the correlations between the hemodynamic indices and biopsy Gleason score were studied.

Results

Prostate cancer was detected in 41 of 103 patients and there were significant differences in the hemodynamic indices between the biopsy sites of the non-malignant patients and prostate cancer lesions (p < 0.05). The prostate biopsies revealed 154 prostate cancer lesions, including 31 low-grade lesions and 123 high-grade lesions. The hemodynamic indices AT and TTP of high-grade tumors were significantly shorter than those of low-grade tumors (p = 0.001, 0.002). In addition, high-grade peripheral zone (PZ) tumors had higher PI than low-grade PZ tumors (p = 0.009). The PZ prostate cancer Gleason score correlated with PI, AT and TTP, with Spearman correlation coefficients of 0.223, -0.335, and -0.351, respectively (p = 0.013, < 0.001 and < 0.001).

Conclusion

Contrast-enhanced ultrasound measurements of hemodynamic indices correlate with the prostate cancer Gleason score.     

Intratumoral Metabolic Heterogeneity for Prediction of Disease Progression After Concurrent Chemoradiotherapy in Patients with Inoperable Stage III Non-Small-Cell Lung Cancer

Purpose

We evaluated the value of variable ¹⁸F-FDG PET/CT parameters for the prediction of disease progression after concurrent chemoradiotherapy (CCRT) in patients with inoperable stage III non-small-cell lung cancer (NSCLC).

Methods

One hundred sixteen pretreatment FDG PET/CT scans of inoperable stage III NSCLC were retrospectively reviewed (stage IIIA: 51; stage IIIB: 65). The volume of interest was automatically drawn for each primary lung tumor, and PET parameters were assessed as follows: maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV) using the boundaries presenting SUV intensity exceeding 3.0, and the area under the curve of the cumulative SUV-volume histograms (AUC-CSH), which is known to reflect the tumor heterogeneity. Progression-free survival (PFS), locoregional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were compared with each PET and clinical parameters by univariate and multivariate survival analysis.

Results

In the ROC analysis, the optimal cutoff values of SUV_max, MTV (cm³), and AUC-CSH for prediction of PFS were determined as 21.5, 27.7, and 4,800, respectively. In univariate analysis, PFS was statistically significantly reduced in those with AUC-CSH < 4,800 (p = 0.004). In multivariate analysis, AUC-CSH and SUV_max were statistically significant independent prognostic factors (HR 3.35, 95 % CI 1.79–6.28, p < 0.001; HR 0.25, 95 % CI 0.09–0.70, p = 0.008, respectively). Multivariate analysis showed that AUC-CSH was the most significant independent prognostic factor for LRFS and DMFS (HR 3.27, 95 % CI 1.54–6.94, p = 0.002; HR 2.79, 95 % CI 1.42–5.50, p = 0.003).

Conclusions

Intratumoral metabolic heterogeneity of primary lung tumor in ¹⁸F-FDG PET/CT can predict disease progression after CCRT in inoperable stage III NSCLC.     

18F-FAMT in patients with multiple myeloma: clinical utility compared to 18F-FDG

Objective

l-[3-¹⁸F]-alpha-methyltyrosine (¹⁸F-FAMT) is an amino-acid tracer for positron emission tomography (PET), with uptake related to overexpression of L-type amino-acid transporter 1 and proliferative activity in tumour cells. This study evaluated the diagnostic performance of ¹⁸F-FAMT PET compared with 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) PET in patients with multiple myeloma (MM).

Methods

Eleven patients with MM (newly diagnosed, n?=?3; relapsed after treatment, n?=?8) underwent whole-body ¹⁸F-FAMT and ¹⁸F-FDG PET within a 2-week interval. Magnetic resonance imaging (MRI) of the spine was also performed to assess patterns of bone marrow infiltration. Tracer uptake was semi-quantitatively evaluated using maximal standardized uptake value (SUV_max). Mean SUV was also determined for normal bone marrow and the aortic arch as mediastinal background SUV to calculate lesion-to-bone marrow (L/B) and lesion-to-mediastinum (L/M) ratios, respectively. Those values were statistically compared using Student??s t test.

Results

In 8 patients showing focal infiltration on MRI, 34 FDG-avid bone lesions were identified, with each showing increased FAMT uptake. Mean SUV_max and L/B ratio of FDG (3.1?±?1.2 and 3.3?±?1.9, respectively) were significantly higher than those of FAMT (2.0?±?1.0 and 2.6?±?1.1, respectively; p?<?0.05 each). In contrast, the L/M ratio of FDG showed no significant difference to that of FAMT (2.2?±?1.0 and 2.4?±?1.2, respectively; p?=?0.3).

Conclusions

Clear ¹⁸F-FAMT PET uptake was seen in most ¹⁸F-FDG-avid lesions among patients with MM, and an equivalent semi-quantitative value was obtained using L/M ratio. Our preliminary data suggest that ¹⁸F-FAMT PET provides a useful imaging modality for detecting active myelomatous lesions.     

High-Definition Computed Tomography for Coronary Artery Stent Imaging: a Phantom Study

Objective

To assess the performance of a high-definition CT (HDCT) for imaging small caliber coronary stents (≤ 3 mm) by comparing different scan modes of a conventional 64-row standard-definition CT (SDCT).

Materials and Methods

A cardiac phantom with twelve stents (2.5 mm and 3.0 mm in diameter) was scanned by HDCT and SDCT. The scan modes were retrospective electrocardiography (ECG)-gated helical and prospective ECG-triggered axial with tube voltages of 120 kVp and 100 kVp, respectively. The inner stent diameters (ISD) and the in-stent attenuation value (AV_in-stent) and the in-vessel extra-stent attenuation value (AV_in-vessel) were measured by two observers. The artificial lumen narrowing (ALN = [ISD - ISD_measured]/ISD) and artificial attenuation increase between in-stent and in-vessel (AAI = AV_in-stent - AV_in-vessel) were calculated. All data was analyzed by intraclass correlation and ANOVA-test.

Results

The correlation coefficient of ISD, AV_in-vessel and AV_in-stent between the two observers was good. The ALNs of HDCT were statistically lower than that of SDCT (30 ± 5.7% versus 35 ± 5.4%, p < 0.05). HDCT had statistically lower AAI values than SDCT (15.7 ± 81.4 HU versus 71.4 ± 90.5 HU, p < 0.05). The prospective axial dataset demonstrated smaller ALN than the retrospective helical dataset on both HDCT and SDCT (p < 0.05). Additionally, there were no differences in ALN between the 120 kVp and 100 kVp tube voltages on HDCT (p = 0.05).

Conclusion

High-definition CT helps improve measurement accuracy for imaging coronary stents compared to SDCT. HDCT with 100 kVp and the prospective ECG-triggered axial technique, with a lower radiation dose than 120 kVp application, may be advantageous in evaluating coronary stents with smaller calibers (≤ 3 mm).     

恶性血液肿瘤脊柱骨髓弥漫性浸润的动态对比增强MR灌注成像

目的 评价动态对比增强MR灌注成像对恶性血液肿瘤脊柱骨髓弥漫性浸润性病变的诊断价值. 资料与方法 经骨髓组织活检确诊的恶性血液肿瘤26例和20例正常对照者行腰椎动态对比增强MR灌注成像检查.计算峰值增强百分率(Emax)、增强斜率(ES)和到达峰值时间(TTP). 结果 脊柱骨髓弥漫性恶性浸润组与正常对照组间的Emax、ES和TTP均具有显著差异(P<0.01).骨髓轻度浸润和中度浸润之间的Emax、ES和TTP均具有显著差异(P<0.05).骨髓轻度浸润和重度浸润之间的Emax、ES和TTP均具有显著差异(P<0.01).骨髓中度浸润和重度浸润之间的Emax、ES和TTP无显著差异(P>0.05).Emax、ES和骨髓浸润程度之间具有正相关性(P<0.01),TTP和骨髓浸润程度之间具有负相关性(P<0.01). 结论 动态对比增强MR灌注成像可以判断恶性血液肿瘤是否出现脊柱骨髓弥漫性浸润,灌注参数可以反映骨髓肿瘤细胞浸润程度.     

Prognostic Value of Volume-Based 18F-Fluorodeoxyglucose PET/CT Parameters in Patients with Clinically Node-Negative Oral Tongue Squamous Cell Carcinoma

Objective

To evaluate the prognostic value of volume-based metabolic parameters measured with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) in patients with clinically node-negative (cN0) oral tongue squamous cell carcinoma (OTSCC) as compared with other prognostic factors.

Materials and Methods

In this study, we included a total of 57 patients who had been diagnosed with cN0 tongue cancer by radiologic, ¹⁸F-FDG PET/CT, and physical examinations. The maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumors were measured with ¹⁸F-FDG PET. The prognostic significances of these parameters and other clinical variables were assessed by Cox proportional hazards regression analysis.

Results

In the univariate analysis, pathological node (pN) stage, American Joint Committee on Cancer (AJCC) stage, SUV_max, SUV_avg, MTV, and TLG were significant predictors for survival. On a multivariate analysis, pN stage (hazard ratio = 10.555, p = 0.049), AJCC stage (hazard ratio = 13.220, p = 0.045), and MTV (hazard ratio = 2.698, p = 0.033) were significant prognostic factors in cN0 OTSCC patients. The patients with MTV ≥ 7.78 cm³ showed a worse prognosis than those with MTV < 7.78 cm³ (p = 0.037).

Conclusion

The MTV of primary tumor as a volumetric parameter of ¹⁸F-FDG PET, in addition to pN stage and AJCC stage, is an independent prognostic factor for survival in cN0 OTSCC.     

Assessment of Tissue Viability Using Diffusion- and Perfusion-Weighted MRI in Hyperacute Stroke

Objective

The aim of this study was to investigate the relationship between the diffusion and perfusion parameters in hyperacute infarction, and we wanted to determine the viability threshold for the ischemic penumbra using diffusion- and perfusion-weighted imaging (DWI and PWI, respectively).

Materials and Methods

Both DWI and PWI were performed within six hours from the onset of symptoms for 12 patients who had suffered from acute stroke. Three regions of interest (ROIs) were identified: ROI 1 was the initial lesion on DWI; ROI 2 was the DWI/PWI mismatch area (the penumbra) that progressed onward to the infarct; and ROI 3 was the mismatch area that recovered to normal on the follow-up scans. The ratios of apparent diffusion coefficient (ADC), the relative cerebral blood volume (rCBV), and the time to peak (TTP) were calculated as the lesions'' ROIs divided by the contralateral mirror ROIs, and these values were then correlated with each other. The viability threshold was determined by using the receiver operating characteristic (ROC) curves.

Results

For all three ROIs, the ADC ratios had significant linear correlation with the TTP ratios (p < 0.001), but not with the rCBV ratios (p = 0.280). There was no significant difference for the ADC and rCBV ratios within the ROIs. The mean TTP ratio/TTP delay between the penumbras'' two ROIs showed a significant statistical difference (p < 0.001). The cutoff value between ROI 2 and ROI 3, as the viability threshold, was a TTP ratio of 1.29 (with a sensitivity and specificity of 86% and 73%, respectively) and a TTP delay of 7.8 sec (with a sensitivity and specificity of 84% and 72%, respectively).

Conclusion

Determining the viability thresholds for the TTP ratio/delay on the PWI may be helpful for selecting those patients who would benefit from the various therapeutic interventions that can be used during the acute phase of ischemic stroke.     

Preliminary Application of High-Definition CT Gemstone Spectral Imaging in Hand and Foot Tendons

Objective

To assess the feasibility of visualizing hand and foot tendon anatomy and disorders by Gemstone Spectral Imaging (GSI) high-definition CT (HDCT).

Materials and Methods

Thirty-five patients who suffered from hand or foot pain were scanned with GSI mode HDCT and MRI. Spectrum analysis was used to select the monochromatic images that provide the optimal contrast-to-noise ratio (CNR) for tendons. The image quality at the best selected monochromatic level and the conventional polychromatic images were compared. Tendon anatomy and disease were also analyzed at GSI and MRI.

Results

The monochromatic images at about 65 keV (mean 65.09 ± 2.98) provided the optimal CNR for hand and foot tendons. The image quality at the optimal selected monochromatic level was superior to conventional polychromatic images (p = 0.005, p < 0.05). GSI was useful in visualizing hand and foot tendon anatomy and disorders. There were no statistical differences between GSI and MRI with regard to tendon thickening (χ² = 0, p > 0.05), compression (χ² = 0.5, p > 0.05), absence (χ² = 0, p > 0.05) and rupture (χ² = 0, p > 0.05). GSI was significantly less sensitive than MRI in displaying tendon adhesion (χ² = 4.17, p < 0.05), degeneration (χ² = 4.17, p < 0.05), and tendinous sheath disease (χ² = 10.08, p < 0.05).

Conclusion

GSI with monochromatic images at 65 keV displays clearly the most hand and foot tendon anatomy and disorders with image quality improved, as compared with conventional polychromatic images. It may be used solely or combined with MRI in clinical work, depending on individual patient disease condition.     

Differentiating Focal Eosinophilic Infiltration from Metastasis in the Liver with Gadoxetic Acid-Enhanced Magnetic Resonance Imaging

Objective

To determine the most useful findings of gadoxetic acid-enhanced 3.0 Tesla (T) MRI for differentiating focal eosinophilic infiltration (FEI) from hepatic metastasis with verification of their usefulness.

Materials and Methods

Pathologically or clinically proven 39 FEIs from 25 patients and 79 hepatic metastases from 51 patients were included in the study. Gadoxetic acid-enhanced 3.0T MRI was performed in all cancer patients. Size differences measured between T2-weighted and hepatobiliary-phase images for lesions > 1 cm and morphologic findings (margin, shape, signal intensity on T1- and T2-weighted images, enhancement pattern on dynamic images, and target appearance on hepatobiliary-phase images) were compared between two groups via Student''s t test as well as univariate and multivariate analyses. Diagnostic predictive values of two observers for differentiating two groups were assessed before (session 1) and after (session 2) recognition of results.

Results

Mean size difference (2.1 mm) in FEIs between the two images was significantly greater than for metastases (0.7 mm) (p < 0.05). An ill-defined margin and isointensity on T1-weighted images were independently significant morphologic findings (p < 0.05) for differentiating the two groups. All observers achieved a higher diagnostic accuracy in session 2 (97% and 98%) than session 1 (92% and 89%) with statistical significance in observer 2 (p < 0.05). All observers had significantly higher sensitivities (95%) and negative predictive values (NPVs) (98%) in session 2 than in session 1 (sensitivity, 74% in two observers; NPV, 89% and 88%) (p < 0.05).

Conclusion

With the size change, an ill-defined margin and isointensity on T1-weighted images are the most useful findings for differentiating FEI from hepatic metastasis on gadoxetic acid-enhanced 3.0T MRI.     

Effects of Arsenic Trioxide on Radiofrequency Ablation of VX2 Liver Tumor: Intraarterial versus Intravenous Administration

Objective

Arsenic trioxide (As₂O₃) can be used as a possible pharmaceutical alternative that augments radiofrequency (RF) ablation by reducing tumor blood flow. The aim of this study was to assess the effect of intraarterial and intravenous administration of As₂O₃ on RF-induced ablation in an experimentally induced liver tumor.

Materials and Methods

VX2 carcinoma was grown in the livers of 30 rabbits. As₂O₃ (1 mg/kg) was administered through the hepatic artery (n = 10, group A) or ear vein (n = 10, group B), 30 minutes before RF ablation (125 mA ± 35; 90 ± 5℃). As a control group, 10 rabbits were treated with RF ablation alone (group C). RF was intentionally applied to the peripheral margin of the tumor so that ablation can cover the tumor and adjacent hepatic parenchyma. Ablation areas of the tumor and adjacent parenchymal changes among three groups were compared by the Kruskal-Wallis and Mann-Whitney U test.

Results

The overall ablation areas were 156 ± 28.9 mm² (group A), 119 ± 31.7 (group B), and 92 ± 17.4 (group C, p < 0.04). The ablation area of the tumor was significantly larger in group A (73 ± 19.7 mm²) than both group B (50 ± 19.4, p = 0.02) and group C (28 ± 2.2, p < 0.01). The ratios of the tumoral ablation area to the overall ablation area were larger in group A (47 ± 10.5%) than that of the other groups (42 ± 7.3% in group B and 32 ± 5.6% in group C) (p < 0.03).

Conclusion

Radiofrequency-induced ablation area can be increased with intraarterial or intravenous administration of As₂O₃. The intraarterial administration of As₂O₃ seems to be helpful for the selective ablation of the tumor.     

Histologic Characteristics of Hepatocellular Carcinomas Showing Atypical Enhancement Patterns on 4-Phase MDCT Examination

Objective

To retrospectively define which histologic characteristics of small-sized hepatocellular carcinomas (HCCs) are related to atypical dynamic enhancement on multi-detector computed tomography (MDCT) imaging.

Materials and Methods

Seventy-three patients with 83 HCCs (3 cm or less in diameter) were included in this study. All patients underwent 4-phase MDCT imaging and subsequent surgery within eight weeks. Two independent radiologists blinded to the histologic findings retrospectively classified the HCCs as either typical (showing increased enhancement on arterial phase images followed by washout in late phase images) or atypical lesions demonstrating any other enhancement pattern. From the original pathologic reports, various histologic characteristics including gross morphology, nuclear histologic grades, presence of capsule formation, and capsule infiltration when a capsule was present, were compared among the two groups.

Results

An atypical enhancement pattern was seen in 30 (36.2%) of the 83 HCCs. The mean size of atypical HCCs (1.71 ± 0.764) was significantly smaller than that of typical HCCs (2.31 ± 0.598, p < 0.001). Atypical HCCs were frequently found to be vaguely nodular in gross morphology (n = 13, 43.3%) and to have grade I nuclear grades (n = 17, 56.7%). Capsule formation was significantly more common in typical HCCs (p < 0.001). Capsular infiltration was also more common in typical HCCs (p = 0.001).

Conclusion

HCCs showing atypical dynamic enhancement on MDCT imaging are usually smaller than typical HCCs, vaguely nodular type in gross morphology in most cases, and well-differentiated in nuclear grades, and they lack of capsule formation or capsular infiltration.     

Dynamic 18 F-FDG PET for Assessment of Tumor Physiology in Two Breast Carcinoma Xenografts

Purpose

To compare dynamic 2-deoxy-2-[¹⁸ F]fluoro-D-glucose positron emission tomography (¹⁸ F-FDG PET) parameters in two selected human breast cancer xenografts and to evaluate associations with immunohistochemistry and histology.

Procedures

Dynamic ¹⁸ F-FDG PET of luminal-like MAS98.06 and basal-like MAS98.12 xenografts was performed, and the compartmental transfer rates (k₁,k₂,k₃), blood volume fraction (v_B) and metabolic rate of ¹⁸ F-FDG(MR_FDG) were estimated from pharmacokinetic model analysis. After sacrifice, analyses of hypoxia (pimonidazole), proliferation (Ki-67), vascularization (CD31), glucose transport receptor (GLUT1) and necrosis (HE) was performed. The level of hexokinase 2 (HK2) was estimated from Western blot analysis.

Results

The ¹⁸ F-FDG uptake curves for the two xenografts were significantly different (p < 0.05). k₁ and v_B were higher for MAS98.12 (p < 0.01), while k₃ was higher for MAS98.06 (p < 0.01). MAS98.12 had a higher fraction of stromal tissue and higher microvessel density (MVD), and it was less necrotic and hypoxic than MAS98.06. MAS98.12 had stronger positive GLUT1 staining and lower Ki-67 than MAS98.06. In both models significant correlations were found between k₁ and the GLUT1 score, between k₃ and the level of HK2, and between v_B and MVD.

Conclusions

Significant differences in dynamic ¹⁸ F-FDG parameters between the two human breast cancer xenografts were found. The differences could be explained by underlying histological and physiological characteristics.     

Evaluation of Bone Metastasis from Hepatocellular Carcinoma Using 18F-FDG PET/CT and 99mTc-HDP Bone Scintigraphy: Characteristics of Soft Tissue Formation

Purpose

Bone metastasis from hepatocellular carcinoma (HCC) can present with soft tissue formation, resulting in oncologic emergency. Contrast-enhanced FDG PET/CT and bone scintigraphy were compared to evaluate characteristics of bone metastases with or without soft tissue formation from HCC.

Methods

Of 4,151 patients with HCC, 263 patients had bone metastases. Eighty-five patients with bone metastasis from HCC underwent contrast-enhanced FDG PET/CT. Fifty-four of the enrolled subjects had recent ^99mTc-HDP bone scintigraphy available for comparison. Metastatic bone lesions were identified with visual inspection on FDG PET/CT, and maximum standardized uptake value (SUV_max) was used for the quantitative analysis. Confirmation of bone metastasis was based on histopathology, combined imaging modalities, or serial follow-up studies.

Results

Forty-seven patients (55%) presented with soft tissue formation, while the remaining 38 patients presented without soft tissue formation. Frequent sites of bone metastases from HCC were the spine (39%), pelvis (19%), and rib cage (14%). The soft-tissue-formation group had more frequent bone pain (77 vs. 37%, p < 0.0001), higher SUV_max (6.02 vs. 3.52, p < 0.007), and higher incidence of photon defect in bone scintigraphy (75 vs. 0%) compared to the non-soft-tissue-formation group. FDG PET/CT had higher detection rate for bone metastasis than bone scintigraphy both in lesion-based analysis (98 vs. 53%, p = 0.0015) and in patient-based analysis (100 vs. 80%, p < 0 .001).

Conclusions

Bone metastasis from HCC showed a high incidence of soft tissue formation requiring emergency treatment. Although the characteristic findings for soft tissue formation such as photon defect in bone scintigraphy are helpful in detection, overall detectability of bone metastasis is higher in FDG PET/CT. Contrast-enhanced PET/CT will be useful in finding and delineating soft-tissue-forming bone metastasis from HCC.     

Detrended fluctuation analysis detects altered coordination of running gait in athletes following a heavy period of training

Objectives

To investigate whether functional overreaching affects locomotor system behaviour when running at fixed relative intensities and if any effects were associated with changes in running performance.

The Prognostic Value of 18F-FDG PET/CT for Early Recurrence in Operable Breast Cancer: Comparison with TNM Stage

Purpose

We evaluated whether the maximum standardized uptake values (SUV_max) of primary tumor from the initial staging by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) of patients with breast cancer could identify patients at risk for early recurrence within 2 years, particularly in comparison to the American Joint Committee on Cancer (AJCC) stage.

Methods

We reviewed the staging ¹⁸F-FDG PET/CT images of patients with primary breast cancer and their medical records. The SUV_max of the primary tumor was measured. The presence or absence of FDG uptake in the axillary lymph node (ALN) was also assessed. The patient’s pathologic primary tumor stage (pT), pathologic regional lymph node stage (pN), stage grouping, age, estrogen receptor (ER) and progesterone receptor (PR) status, and neoadjuvant chemotherapy history were evaluated with the FDG uptake parameters for recurrence within 2 years following the end of first-line therapy.

Results

Recurrence within 2 years was present in 9.1 % (n = 40) out of the 441 patients assessed. The FDG uptake in ALN, pT, pN, stage grouping and neoadjuvant chemotherapy history were prognostic for early recurrence, while primary tumor SUV_max, age, and ER or PR status were not significant on logistic regression. On multivariate analysis, only the stage grouping (odds ratio 2.79; 95 % CI 1.73, 4.48; p < 0.0001) and neoadjuvant chemotherapy history (odds ratio 2.70; 95 % CI 1.22, 5.98; p = 0.0141) could identify patients at increased risk for recurrence within 2 years.

Conclusions

Primary tumor FDG uptake measured by SUV_max, and visual assessment of FDG uptake in the ALN in the initial staging PET/CT of patients with breast cancer may not have additional prognostic value compared with the AJCC stage grouping for early recurrence.     

Prognostic Value of Volume-Based Metabolic Parameters Measured by 18F-FDG PET/CT of Pancreatic Neuroendocrine Tumors

Purpose

To date, the prognostic value of ¹⁸F-FDG PET/CT for patients with pancreatic neuroendocrine tumors (PNETs) has not been well characterized. We investigated the prognostic value of volumetric parameters using ¹⁸F-FDG PET/CT in this patient population.

Methods

We retrospectively reviewed 20 cases of pathologically proven PNET in patients who had undergone pre-therapeutic ¹⁸F-FDG PET/CT. PET parameters including maximum and average standardized uptake values (SUV_max, SUV_ave), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor were measured using a threshold SUV to determine the boundaries of the tumors. Univariate and multivariate survival analyses were performed with adjustments for PET parameters and other clinical values.

Results

The median clinical follow-up was 22.3 (range, 1.2–95.4) months. Cancer-related death occurred in 5 of 20 patients (25 %). Patients had clinical or pathological stages of I in seven patients, II in six patients, III in three patient, and IV in four patients. According to the WHO histological classification of subtypes, 3 patients exhibited well-differentiated PNETs, 13 patients had well-differentiated endocrine carcinomas, and 4 had poorly differentiatedendocrine carcinomas. Univariate analysis showed that tumor size (p = 0.028), AJCC stage (p = 0.009), T stage (p = 0.028), M stage (p = 0.029), treatment modality (p = 0.045), MTV (p = 0.003) and TLG (p = 0.027) were significant predictors of overall survival. On multivariate analysis, MTV (HR = 10.859, p = 0.031) was a significant independent predictor of overall survival along with the AJCC stage (HR = 11.556, p = 0.027).

Conclusion

In patients with PNETs, the MTV of the primary tumor as measured by ¹⁸F-FDG PET/CT along with the AJCC stage may be a significant independent prognostic factor for overall survival.     

Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage in Pediatric Chest Digital Radiography

Objective

The quality and radiation dose of different tube voltage sets for chest digital radiography (DR) were compared in a series of pediatric age groups.

Materials and Methods

Forty-five hundred children aged 0-14 years (yr) were randomly divided into four groups according to the tube voltage protocols for chest DR: lower kilovoltage potential (kVp) (A), intermediate kVp (B), and higher kVp (C) groups, and the fixed high kVp group (controls). The results were analyzed among five different age groups (0-1 yr, 1-3 yr, 3-7 yr, 7-11 yr and 11-14 yr). The dose area product (DAP) and visual grading analysis score (VGAS) were determined and compared by using one-way analysis of variance.

Results

The mean DAP of protocol C was significantly lower as compared with protocols A, B and controls (p < 0.05). DAP was higher in protocol A than the controls (p <0.001), but it was not statistically significantly different between B and the controls (p = 0.976). Mean VGAS was lower in the controls than all three protocols (p < 0.001 for all). Mean VGAS did not differ between protocols A and B (p = 0.334), but was lower in protocol C than A (p = 0.008) and B (p = 0.049).

Conclusion

Protocol C (higher kVp) may help optimize the trade-off between radiation dose and image quality, and it may be acceptable for use in a pediatric age group from these results.