Dual-Energy CT-Based Bone Marrow Imaging in Multiple Myeloma: Assessment of Focal Lesions in Relation to Disease Status and MRI Findings.

RATIONALE AND OBJECTIVES: To assess focal multiple myeloma bone lesions via dual-energy CT-based virtual noncalcium (VNCa) bone marrow imaging in relation to the overall hematological disease status and MRI findings. MATERIALS AND METHODS: We retrospectively evaluated 103 focal osteolytic lesions of the axial skeleton in VNCa bone marrow images of 32 patients. Region of interest-based attenuation measurements were correlated with T1w signal intensity and apparent diffusion coefficient (ADC). Results were compared between patients in active and inactive disease. Receiver operating characteristic analysis was performed to determine a cut-off value of VNCa attenuation for differentiation between the two groups. Standard of reference was the overall disease status according to International Myeloma Working Group response criteria. RESULTS: Mean attenuation difference between lesions and background bone marrow was significantly lower in inactive disease (16 HU, SD 30) compared to active disease (35 HU, SD 29). VNCa attenuation measurement allowed for differentiation between active and inactive disease with a sensitivity of 92% and a specificity of 58% at a cut-off value of -21 HU. VNCa attenuation was negatively correlated to T1w signal intensity (Spearman's ρ -0.617, p < 0.001) and positively correlated to ADC (Spearman's ρ 0.521, p < 0.001). CONCLUSION: Quantitative assessment of attenuation of focal osteolytic lesions in VNCa bone marrow images allows differentiation between overall active and inactive disease with higher attenuation signifying an increasing likelihood of active disease. This is supported by a significant positive correlation between the attenuation and the ADC, as well as a corresponding inverse correlation to T1w signal intensity.

Intraprocedural cone-beam CT with parenchymal blood volume assessment for transarterial chemoembolization guidance: Impact on the effectiveness of the individual TACE sessions compared to DSA guidance alone.

PURPOSE: The objective of this retrospective single centre study was to evaluate the impact of intraprocedural cone-beam CT with parenchymal blood volume assessment (PBV-CBCT) for guidance of transarterial chemoembolization with drug-eluting beads (DEB-TACE) in HCC patients on the effectiveness (local tumour response, survival and number of individual TACE sessions) compared to guidance solely by digital subtraction angiography (DSA). METHOD: n = 179 HCC patients (mean age, 77.4 y) undergoing DEB-TACE, with (n = 28) and without (n = 151) PBV-CBCT, using 100-300 µm microspheres loaded with epirubicin were retrospectively analysed. Tumour response according to mRECIST, overall survival and number of TACE interventions as well as laboratory parameters for liver function and inflammation were recorded. The analysis of the influence of intraprocedural PBV-CBCT was based on matched pair analysis (CBCT n = 28 vs. DSA n = 28). Gender, tumour number, tumour size and HCC risk factors were equally distributed between both groups. RESULTS: Response rates according to mRECIST:CBCT: PD: 7%, SD: 28 %, PR: 46 %, CR: 18 %; DSA: PD: 7 %, SD: 32 %, PR: 39 %, CR: 21 % (p = 0.174). Median OS: CBCT: 44.1 months; DSA: 28.8 months (p = 0.815). Median TACE number: CBCT: 2.0; DSA: 3.0 (p = 0.046). CONCLUSIONS: The use of intraprocedural PBV-CBCT for TACE guidance reduced the number of re-interventions, with no negative effects on tumour response and overall survival. The study findings support the use of PBV-CBCT for DEB-TACE guidance as the improved immediate feedback leads to a considerable increase of the treatment efficiency and helps to avoid unnecessary re-interventions.

Shear Wave Elastography for Assessment of Muscular Abnormalities Related to Systemic Sclerosis.

RATIONALE AND OBJECTIVES: To assess muscular abnormalities related to systemic sclerosis (SSc) using shear wave elastography and correlate results with those of clinical tests. MATERIALS AND METHODS: We evaluated 55 patients (mean age: 50.4 years; range: 18-88; 34 female) with SSc before treatment and choose muscle groups based on cutaneous involvement and functional impairment [forearms (9); thighs (41); thenar/hypothenar (5)]. We performed shear wave elastography in two orientations to access heterogeneity using virtual touch IQ and mean shear wave velocity values (SWV) and measured skin and fascia thickness. We compared SWVs to the modified Rodnan skin score (mRSS). Twenty-two healthy controls (mean age: 52.0; range: 19-88; 7 female) underwent the same protocol. RESULTS: SWV pattern analysis (homogeneous vs heterogeneous) detected SSc with sensitivity/specificity/negative predictive value/positive predictive value0.79/0.81/0.91/0.62 in transverse and 0.75/0.18/0.91/0.56 in longitudinal orientation. In patients we found poor correlation between SWVs and mRSS but a cutoff of mRSSE = 20 separated them significantly (p < 0.01). Skin and muscle fascia were significantly thicker in patients vs. controls (p < 0.001). CONCLUSION: SSc involves more than increased skin and fascial thickness which is not fully represented by mRSS. Elasticity differs in muscles with and without SSc. The former shows higher SWV and increased heterogeneity in transversal planes of muscular fibers.

Mid-term response assessment in multiple myeloma using a texture analysis approach on dual energy-CT-derived bone marrow images - A proof of principle study.

PURPOSE: To identify textural features on dual-energy CT (DECT)-generated virtual non calcium (VNC) bone marrow images in a small group of patients with multiple myeloma undergoing systemic treatment which could potentially help for mid-term response assessment. METHODS: 44 patients (59.1 ±â€¯11.2 yr.) with multiple myeloma who underwent unenhanced whole-body reduced-dose DECT before and after systemic therapy were evaluated. All patients had current hematologic laboratory tests including serum levels of immunoglobulins, albumin, and total proteins. Using DECT post-processing, bone marrow images of the axial skeleton were reconstructed. The vertebral bodies T10-L5 were segmented for quantification of 1st order (n = 18) and 2nd order Gray Level Co-occurrence Matrix (GLCM) textural features (n = 23) based on an open-source radiomics library (Pyradiomics), which were then compared with the hematologic response category to treatment. Five patients underwent only active surveillance at intervals after previous successful therapy. RESULTS: According to hematologic diagnosis, 29 patients were classified as complete response (CR), 10 as partial response (PR) and 5 as stable disease (SD). We observed a significant drop of the 1st order textural features "10th percentile" (p = 0.009), "median" (p = 0.01), and "minimum" (p < 0.0001) after treatment, whereas the 1st order feature "range" (p = 0.0004) and the 2nd order GLCM feature "difference variance" (p = 0.007) significantly increased in patients experiencing CR. A similar trend, however, without statistical significance, could be observed in patients achieving PR after treatment. 2nd order GLCM feature "difference variance" proved to be a significant discriminator (p = 0.01) between patients with CR and PR (sensitivity 0.93, specificity 0.70) for a cut-off value of -0.28. In patients classified CR, both the mean serum protein and the beta-2 microglobulin decreased after treatment, whereas the serum albumin increased (p < 0.01). The same trend without significance could be observed in patients classified PR. CONCLUSIONS: Changes in textural features applied on VNC bone marrow images in the pre- and posttreatment settings correlate well with myeloma-specific hematologic parameters and provide complementary information for the assessment of the late effects of treatment on the bone marrow.

Extended Texture Analysis of Non-Enhanced Whole-Body MRI Image Data for Response Assessment in Multiple Myeloma Patients Undergoing Systemic Therapy.

Identifying MRI-based radiomics features capable to assess response to systemic treatment in multiple myeloma (MM) patients. Retrospective analysis of whole-body MR-image data in 67 consecutive stage III MM patients (40 men; mean age, 60.4 years). Bone marrow involvement was evaluated using a standardized MR-imaging protocol consisting of T1w-, short-tau inversion recovery- (STIR-) and diffusion-weighted-imaging (DWI) sequences. Ninety-two radiomics features were evaluated, both in focally and diffusely involved bone marrow. Volumes of interest (VOI) were used. Response to treatment was classified according to International Myeloma Working Group (IMWG) criteria in complete response (CR), very-good and/or partial response (VGPR + PR), and non-response (stable disease (SD) and progressive disease (PD)). According to the IMWG-criteria, response categories were CR (n = 35), VGPR + PR (n = 19), and non-responders (n = 13). On apparent diffusion coefficient (ADC)-maps, gray-level small size matrix small area emphasis (Gray Level Size Zone (GLSZM) small area emphasis (SAE)) significantly correlated with CR (p < 0.001), whereas GLSZM non-uniformity normalized (NUN) significantly (p < 0.008) with VGPR/PR in focal medullary lesions (FL), whereas in diffuse involvement, 1st order root mean squared significantly (p < 0.001) correlated with CR, whereas for VGPR/PR Log (gray-level run-length matrix (GLRLM) Short Run High Gray Level Emphasis) proved significant (p < 0.003). On T1w, GLRLM NUN significantly (p < 0.002) correlated with CR in FL, whereas gray-level co-occurrence matric (GLCM) informational measure of correlation (Imc1) significantly (p < 0.04) correlated with VGPR/PR. For diffuse myeloma involvement, neighboring gray-tone difference matrix (NGTDM) contrast and 1st order skewness were significantly associated with CR and VGPR/PR (p < 0.001 for both). On STIR-images, CR correlated with gray-level co-occurrence matrix (GLCM) Informational Measure of Correlation (IMC) 1 (p < 0.001) in FL and 1st order mean absolute deviation in diffusely involved bone marrow (p < 0.001). VGPR/PR correlated at best in FL with GSZLM size zone NUN (p < 0.019) and in all other involved medullary areas with GLSZM large area low gray level emphasis (p < 0.001). GLSZM large area low gray level emphasis also significantly correlated with the degree of bone marrow infiltration assessed histologically (p = 0.006). GLCM IMC 1 proved significant throughout T1w/STIR sequences, whereas GLSZM NUN in STIR and ADC. MRI-based texture features proved significant to assess clinical and hematological response (CR, VPGR, and PR) in multiple myeloma patients undergoing systemic treatment.

Computed tomography texture analysis for assessment of chemotherapy response of Hodgkin lymphoma.

The aim of this study was to test the hypothesis that computed tomography texture analysis (CTTA) is accurate for response assessment of Hodgkin lymphoma (HL).A total of 100 patients with HL were identified. CTTA in baseline and interim staging was performed generating volume of interests in lymphoma tissue from which CTTA features including 1st, 2nd, and higher order textural features were extracted. Baseline and interim 2-deoxy-fluor-glucose positron emission tomography results were used to determine therapy response and compared to CTTA in terms of patient outcome.At interim, 1st-order features yielded a significant drop (e.g., entropy of heterogeneity, P = .01) or a significant rise (deviation, P < .001), whereas 2nd and higher order features decreased (e.g., entropy of co-occurrence matrix, P < .001). Patients achieving complete remission at end of treatment had a significantly lower entropy of heterogeneity at baseline and interim compared to patients achieving partial remission (P < .05).CT textural features change in parallel to metabolic therapy response, and are therefore a feasible diagnostic tool for a more accurate response assessment of HL.

Assessment of Hepatic Perfusion Using GRASP MRI: Bringing Liver MRI on a New Level.

PURPOSE: The aim of this study was to demonstrate the feasibility of hepatic perfusion imaging using dynamic contrast-enhanced (DCE) golden-angle radial sparse parallel (GRASP) magnetic resonance imaging (MRI) for characterizing liver parenchyma and hepatocellular carcinoma (HCC) before and after transarterial chemoembolization (TACE) as a potential alternative to volume perfusion computed tomography (VPCT). METHODS AND MATERIALS: Between November 2017 and September 2018, 10 patients (male = 8; mean age, 66.5 ± 8.6 years) with HCC were included in this prospective, institutional review board-approved study. All patients underwent DCE GRASP MRI with high spatiotemporal resolution after injection of liver-specific MR contrast agent before and after TACE. In addition, VPCT was acquired before TACE serving as standard of reference. From the dynamic imaging data of DCE MRI and VPCT, perfusion maps (arterial liver perfusion [mL/100 mL/min], portal liver perfusion [mL/100 mL/min], hepatic perfusion index [%]) were calculated using a dual-input maximum slope model and compared with assess perfusion measures, lesion characteristics, and treatment response using Wilcoxon signed-rank test. To evaluate interreader agreement for measurement repeatability, the interclass correlation coefficient (ICC) was calculated. RESULTS: Perfusion maps could be successfully generated from all DCE MRI and VPCT data. The ICC was excellent for all perfusion maps (ICC ≥ 0.88; P ≤ 0.001). Image analyses revealed perfusion parameters for DCE MRI and VPCT within the same absolute range for tumor and liver tissue. Dynamic contrast-enhanced MRI further enabled quantitative assessment of treatment response showing a significant decrease (P ≤ 0.01) of arterial liver perfusion and hepatic perfusion index in the target lesion after TACE. CONCLUSIONS: Dynamic contrast-enhanced GRASP MRI allows for a reliable and robust assessment of hepatic perfusion parameters providing quantitative results comparable to VPCT and enables characterization of HCC before and after TACE, thus posing the potential to serve as an alternative to VPCT.

Prognosis assessment in metastatic gastrointestinal stromal tumors treated with tyrosine kinase inhibitors based on CT-texture analysis.

PURPOSE: Identification of prognostic CT-textural features in patients with gastrointestinal stromal tumors undergoing tyrosine kinase inhibitor (TKI) therapy. METHODS AND MATERIALS: We identified 25 GIST patients (mean age, 70.58 ± 9.7 years; range, 41.25-84.08 years; 20 males, 5 females) with a total of 123 scans, each examined with a standardized CT protocol between 1/2014-7/2018. 92 texture features, based on pyradiomics library, were extracted and correlated to response categories; evaluated with help of modified Choi criteria. All patients underwent therapy with imatinib in the first line and different tyrosine kinase inhibitors after disease progression. KIT and PDGFR-mutations were registered in all patients as well as the number of previous treatment regimens, patient's age as well as gender and the presence of contrast enhancement (vitality) in tumor. The lesion with the largest diameter was chosen and contoured using the spherical VOI tool. Inter-rater testing was performed by a second experienced radiologist. Regression and AUC analysis was performed. RESULTS: Ten variables could be confirmed to be significantly associated with disease progression. Of them, four textural parameters were significantly positively associated with disease progression and negatively with progression free survival (Glcm Id [grey-level co-occurrence matrix inverse difference], p = 0.012, HR 3.83; 95% CI 1.697-8.611, Glcm Idn [grey-level co-occurrence matrix inverse difference normalized], p = 0.045, HR 2.06, 95% CI 1.015-4.185, Glrlm [grey-level run length matrix] normalized, p = 0.005, HR 3.181; 95% CI 1.418-7.138 and Ngtdm [neighboring grey-tone difference matrix] coarseness, p < 0.001, HR 3.156, 95% CI 1.554-6.411). Single variables were shown to be significantly inferior to the combination of all variables. After 6 months, 90% of patients with 0-1 risk factors (group 1), 64.4% with 2-3 risk variables and 38.1% of patients presenting > 3 structural risk variables showed stable disease. Gclm Id, Gclm Idn and Glrlm non-uniformity were associated with the number of previous treatments, Glrlm non-uniformity also with tumor vitality (enhancement), whereas Gclm Idn and Ngtdm coarseness were associated with the number of tumor mutations. CONCLUSION: Some of the CT-textural features correlate with disease progression and the progressive free survival as well as with the number of gene mutations and the number of treatment regimens the patients were exposed to as well as with the tumor enhancement. All these features reflect tumor homogeneity.

Dose Optimization of Perfusion-derived Response Assessment in Hepatocellular Carcinoma Treated with Transarterial Chemoembolization: Comparison of Volume Perfusion CT and Iodine Concentration.

RATIONALE AND OBJECTIVES: We assessed the value of iodine concentration (IC) as a perfusion-derived response marker for hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) in comparison with volume perfusion computed tomography (VPCT) parameters. MATERIALS AND METHODS: Forty-one HCC lesions in 32 patients examined before and after TACE were analyzed retrospectively. VPCT-parameters were calculated and lesion iodine-maps were computed using subtraction of the baseline and the scan 7 seconds after aortic peak enhancement from the corresponding 80 kVp-VPCT data set. Modified RECIST was used as standard response criteria. Comparisons were performed using Student's t test for normal distributed data and Mann-Whitney U test for non-normal distributed data. Additionally, correlation analysis, receiver operating characteristics (ROC) and interreader agreement were assessed. RESULTS: In responding lesions, mean pre-TACE IC and blood flow (BF) were 131.2 mg/100 mL and 96.7 mL/100 mL/min, decreasing to IC 25.6 mg/100 mL (P < 0.001) and BF 28.5 mL/100 mL/min (P < 0.001) post-TACE. In nonresponding lesions, the values remained almost unchanged: pre-TACE: mean BF 79.3 mL/100 mL/min and mean IC 90.4 mg/100 mL; post-TACE: mean BF 71.3 mL/100 mL/min (n.s.) and mean IC 105.4 mg/100 mL (n.s.). Differences in IC-values revealed a high sensitivity/specificity of 96.7%/81.8%. IC and VPCT-parameters showed strong, positive correlations. Mean volume CT dose index for VPCT was 63.4 mGy and 4.9 mGy for iodine maps. CONCLUSION: Thus, IC is a meaningful perfusion marker for local therapy response monitoring in HCC that can be acquired with low radiation dose. This information is important for further therapy response applications using dual and single energy CT.

Clinical assessment of dysphagia in neurodegeneration (CADN): development, validity and reliability of a bedside tool for dysphagia assessment.

Screening assessments for dysphagia are essential in neurodegenerative disease. Yet there are no purpose-built tools to quantify swallowing deficits at bedside or in clinical trials. A quantifiable, brief, easy to administer assessment that measures the impact of dysphagia and predicts the presence or absence of aspiration is needed. The Clinical Assessment of Dysphagia in Neurodegeneration (CADN) was designed by a multidisciplinary team (neurology, neuropsychology, speech pathology) validated against strict methodological criteria in two neurodegenerative diseases, Parkinson's disease (PD) and degenerative ataxia (DA). CADN comprises two parts, an anamnesis (part one) and consumption (part two). Two-thirds of patients were assessed using reference tests, the SWAL-QOL symptoms subscale (part one) and videofluoroscopic assessment of swallowing (part two). CADN has 11 items and can be administered and scored in an average of 7 min. Test-retest reliability was established using correlation and Bland-Altman plots. 125 patients with a neurodegenerative disease were recruited; 60 PD and 65 DA. Validity was established using ROC graphs and correlations. CADN has sensitivity of 79 and 84% and specificity 71 and 69% for parts one and two, respectively. Significant correlations with disease severity were also observed (p < 0.001) for PD with small to large associations between disease severity and CADN scores for DA. Cutoff scores were identified that signal the presence of clinically meaningful dysphagia symptomatology and risk of aspiration. The CADN is a reliable, valid, brief, quantifiable, and easily deployed assessment of swallowing in neurodegenerative disease. It is thus ideally suited for both clinical bedside assessment and future multicentre clinical trials in neurodegenerative disease.

C-arm computed tomography and volume perfusion computed tomography (VPCT)-based assessment of blood volume changes in hepatocellular carcinoma in prediction of midterm tumor response to transarterial chemoembolization: a single center retrospective trial.

BACKGROUND: This study aims to evaluate immediate changes in perfusion parameters in hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE) in C-arm computed tomography (CT) and volume perfusion CT (VPCT) and prediction of midterm tumor response. METHODS: Twenty-five patients (median age 66, range 61 to 75 years) with 62 HCC lesions undergoing TACE received immediate pre- and post-interventional assessment by C-arm CT and VPCT. Cross-sectional imaging was analyzed at baseline and approximately 12 weeks after TACE according to modified RECIST criteria. Outcome was defined as objective response (OR, > 30 % reduction of viable tumor) or non-OR. Perfusion parameters were evaluated in C-arm CT [parenchymal blood volume (PBV)] and VPCT [blood volume (BV) and blood flow (BF)]. Ratios of perfusion parameters before and after TACE within the tumor and the non-affected liver parenchyma were calculated. RESULTS: Correlation between tumor PBV and BV revealed a moderate correlation (rho = 0.45, p = 0.005). In non-affected liver parenchyma, a significant decrease in PBV was seen, compared to a significant increase in BF and BV. Perfusion ratios in HCC lesions were significantly (p < 0.05) increased in OR group compared to non-OR patients in C-arm CT and VPCT: PBV ratio (0.95 (0.06) to 0.67 (0.38), BV ratio 0.63 (0.34) to 0.15 (0.6), and BF ratio 0.6 (0.32) to 0.22 (0.51). Logistic regression including PBV and BF allowed prediction of OR (sensitivity 88 %/specificity of 83 %). CONCLUSIONS: Perfusion parameters acquired by C-arm CT and VPCT cannot simply be substituted by each other, but show similar capability in prediction of midterm tumor response.

Comparison of volume perfusion computed tomography and contrast-enhanced ultrasound for assessment of therapeutic effect of transarterial chemoembolization in patients with hepatocellular carcinoma: a preliminary report.

BACKGROUND: Evaluation of transarterial chemoembolization (TACE) by using contrast-enhanced ultrasound (CEUS) and volume perfusion computed tomography (VPCT) as methods that display tumor vascularization. PURPOSE: To assess early results of TACE in patients with hepatocellular carcinoma (HCC) using CEUS and VPCT. MATERIAL AND METHODS: Twenty patients with HCC underwent CEUS and VPCT in the pre- and post-TACE setting (1 day). Hepatic perfusion index (HPI), arterial liver perfusion (ALP), blood flow (BF), and blood volume (BV) were measured with VPCT. Peak intensity (PI), time-to-peak (TTP), and regional blood flow (RBF) were measured with CEUS. Sensitivity, specificity, negative and positive predictive values, and cutoff values for these parameters were calculated. Immediate tumor response after TACE was classified as responder or non-responder. Results were compared with those at follow-up after 2 and 4 months (FU2mo/FU4mo) following modified RECIST. RESULTS: CEUS and VPCT showed comparable immediate post-TACE results in 20/20 cases. Complete response was confirmed in 10/20 patients at FU2mo and in 9/20 at FU4mo. For responders, reduction in HPI, ALP, BV, and BF at day 1 post TACE proved significant (P < 0.001). For non-responders, the course of all VPCT parameters proved non-significant. A cutoff of 40% reduction in HPI and a reduction in ALP of >29.6%, in BV of >41.4%, or in BF of >53.1% was indicative of response according to FU2mo. For responders only, changes in PI (P < 0.001), TTP (P < 0.01), and BF (P < 0.01) proved significant whereas for non-responders, all CEUS parameters proved non-significant. CONCLUSION: CEUS performs equally to VPCT for assessment of early response to TACE in HCC by a lesion-by-lesion assessment and showed prognostic value at mid-term.

Perfusion-based assessment of disease activity in untreated and treated patients with aortitis and chronic periaortitis: correlation with CT morphological, clinical and serological data.

OBJECTIVE: To evaluate the role of perfusion-based assessment of inflammatory activity in patients with treated and untreated aortitis and chronic periaortitis as compared with clinical and serological markers. METHODS: 35 patients (20 females; median age 66 years) with (peri) aortitis were retrospectively evaluated. All patients had clinical symptoms prompting at the time of imaging. All patients first underwent whole-body contrast-enhanced CT and subsequently segmental volume perfusion CT for assessment of the degree of vascularization of (peri) aortitis as a surrogate marker for inflammatory activity. Blood flow, blood volume, volume transfer constant (k-trans), time to peak and mean transit time were determined. The thickness of the increased connective tissue formation was measured. Perfusion data were correlated with clinical symptoms and acute-phase inflammatory parameters such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and leukocyte number. RESULTS: 21 of 35 patients were untreated and 14 of 35 had previous/ongoing immunosuppression. The interobserver agreement was good (κ = 0.78) for all perfusion parameters. Average values of perfusion parameters were higher in untreated patients but remained abnormally elevated in treated patients as well. Perfusion data and ESR and CRP correlated well both in aortitis (p < 0.05) and in periaortitis (p < 0.05). In periaortitis, perfusion parameters agreed well with ESR and CRP values (p < 0.05) only in untreated patients. CONCLUSION: Perfusion CT parameters in untreated aortitis and chronic periaortitis correlate well with serological markers with respect to disease activity assessment. However, in treated periaortitis, correlations were weak, suggesting an increased role for (perfusion-based) imaging. ADVANCES IN KNOWLEDGE: Volume perfusion CT may be used for diagnosis of aortitis/periaortitis.

Dual-energy CT: virtual calcium subtraction for assessment of bone marrow involvement of the spine in multiple myeloma.

OBJECTIVE. Dual-energy CT (DECT) enables subtraction of calcium, facilitating the visualization of bone marrow (BM) in the axial skeleton. The purpose of this study was to assess whether DECT BM images have the potential to improve the detection of multifocal and diffuse BM infiltration in multiple myeloma (MM) in comparison with regular CT with MRI as the reference standard. SUBJECTS AND METHODS. This study included 32 consecutive patients who had known MM or presented with monoclonal gammopathy of unknown significance and underwent DECT and MRI of the axial skeleton. The degrees (none, n = 14; moderate, n = 10; and high, n = 8) and patterns (diffuse, n = 10 or multifocal, n = 8) of infiltration were assessed on MR images. Attenuation in BM and CT images in known uninvolved and involved areas was measured. Cutoff values of attenuation in BM images for infiltration in lytic and nonlytic lesions were established by ROC analysis. At least 120 days later, sensitivity and specificity for reading CT images alone and when using additional BM images were evaluated. RESULTS. ROC analysis revealed larger AUC in BM images than in CT images; cutoff values for marrow invasion in BM images were 4 and -3 HU in lytic and nonlytic lesions, respectively. In the blinded reading session, BM images improved the sensitivity for the detection of diffuse infiltration from 0 to as much as 75% for cases with high-grade infiltration. In multifocal patterns, BM images did not significantly change the detection rate. CONCLUSION. BM images have the potential to improve the sensitivity for detection of diffuse BM involvement in comparison with regular CT.

Assessment of tumor vascularity in lung cancer using volume perfusion CT (VPCT) with histopathologic comparison: a further step toward an individualized tumor characterization.

OBJECTIVE: To measure perfusion in different lung cancer subtypes and compare results with histopathological/immunohistochemical results. METHODS: Seventy-two consecutive untreated patients with lung cancer (40 adenocarcinomas, 20 squamous cell, and 12 small cell lung cancers) were enrolled. A 40-second volume perfusion computed tomography of the tumor bulk was obtained. Blood flow (BF), blood volume (BV), and transit constant were determined. Tumor volume and tumor necrosis were determined on contrast-enhanced computed tomography. Pathologic specimens were assessed for microvessel density (MVD), hypoxia-induced transcription (hif-1/-2), and proliferation (Ki-67). RESULTS: Higher MVD is associated with higher BF and BV. Higher tumor grade leads to lower BF but increased necrosis and tumor volume. Markers of hypoxia were independent from perfusion parameters, extent of necrosis or MVD. Blood flow, BV, and MVD were not significantly different among lung cancer subtypes. Transit constant was significantly reduced in small cell lung cancer versus adenocarcinoma. CONCLUSIONS: Perfusion values are related to MVD and tumor grade but vary considerably among lung cancer subtypes.

Assessment of splenic perfusion in patients with malignant hematologic diseases and spleen involvement, liver cirrhosis and controls using volume perfusion CT (VPCT): a pilot study.

RATIONALE AND OBJECTIVES: The aim of this study was to assess splenic perfusion in patients with spleen involvement in malignant hematologic diseases and liver cirrhosis and in controls without hepatosplenic disease using volume perfusion computed tomography. MATERIALS AND METHODS: Between October 2009 and December 2011, 14 hematologic patients with known spleen involvement were recruited. An additional 17 consecutive patients without known splenic or liver disease were enrolled as controls, as well as 29 patients with liver cirrhosis and portal hypertension. A 40-second volume perfusion computed tomographic scan of the upper abdomen was performed. Analysis included measurement of splenic volume, blood flow (BF), blood volume (BV), K(trans), and mean transit time (MTT). RESULTS: In lymphoma patients, mean splenic volume and perfusion parameters were as follows: splenic volume, 1125.34 mL; BF, 61.24 mL/100 mL/min; BV, 16.53 mL/100 mL; K(trans), 37.00 mL/100 mL/min; and MTT, 12.42 seconds. All perfusion values of patients with lymphoma and cirrhosis differed significantly, except for BV, compared to controls. For patients with lymphoma, significant correlations were found between splenic volume and BF (r = -0.683, P = .000), splenic volume and BV (r = -0.525, P = .002), and splenic volume and MTT (r = 0.543, P = .001). During treatment, significant correlations between the diameters of nodular lymphoma target lesions, splenic volume, and the perfusion parameters were present for splenic volume (r = 0.601, P = .002), BF (r = -0.777, P = .000) and BV (r = -0.500, P = .011). CONCLUSIONS: Volume perfusion computed tomography represents a novel tool for the assessment of splenic perfusion. Preliminary results in patients with spleen involvement reveal lower perfusion values compared to controls or patients with cirrhosis. Therefore, this technique might provide additional information in clinical routine.

Assessment of synovitis in erosive osteoarthritis of the hand using DCE-MRI and comparison with that in its major mimic, the psoriatic arthritis.

RATIONALE AND OBJECTIVES: To investigate the diagnostic value of high-resolution dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for assessment of synovitis in erosive osteoarthritis (EOA) of the hand and compare the results with those acquired in its potential mimic, the psoriatic arthritis (PsA). MATERIALS AND METHODS: Twenty-six patients (17 PsA, 9 EOA) were examined at 3 T. The time course of synovial contrast uptake was measured by ROI analysis using a three-dimensional encoded spoiled gradient-echo sequence. Characteristic parameters of synovial uptake curves (time to peak [TTP], peak value, mean transit time [MTT], area under the curve [AUC], and maximum upslope) of PsA and EOA patients were compared using gamma variate analysis and calculation of the late relative enhancement 15 minutes after contrast administration. RESULTS: Enhancement curves of PsA and EOA patients paralleled each other at comparable levels in the early phase after contrast injection without statistical difference in the following calculated characteristic curve parameters: TTP, peak value, MTT, AUC, and maximum upslope. However, significant difference was found in the late relative enhancement 15 minutes after contrast injection (P = .0275) with higher values in EOA patients. CONCLUSION: DCE-MRI provides assessment of synovitis in both patients with EOA and PsA. Interestingly, synovial enhancement characteristics were comparable for the most part in these two disorders. However, late enhancement might help in differentiation which is essential for guiding therapy.

Response assessment in patients with multiple myeloma during antiangiogenic therapy using arterial spin labeling and diffusion-weighted imaging: a feasibility study.

RATIONALE AND OBJECTIVES: To determine whether response to anti-angiogenic therapy in patients with multiple myeloma can be assessed by noncontrast perfusion magnetic resonance imaging (MRI) (ie, arterial-spin-labeling [ASL]), and diffusion-weighted [DWI] MRI. MATERIALS AND METHODS: The study protocol was approved by the local institutional ethic board. Ten consecutive patients (eight men, two women; mean age 60.5 ± 8.5 years) with Stage III multiple myeloma were prospectively included. MRI was performed at baseline, as well as 3 and 8 weeks after onset of antiangiogenic therapy. Functional MRI data were compared with clinical outcome and conventional lesion size and signal-intensity measurements. Differences between baseline and follow-up values for ASL-MRI and DWI-MRI were assessed using a paired Student t-test. RESULTS: Nine patients responded well to therapy, whereas one patient was classified a nonresponder. Temporary changes in signal intensity between baseline and follow-up examinations were inconsistent on T1-weighted (w) and T2w images. Likewise, determination of lesion size at follow-up proved unreliable. ASL showed a marked decrease in perfusion from baseline (251 ± 159 mL/(min*100g)) to follow-up at 3 weeks (115 ± 85 mL/(min*100g), P = .01) and 8 weeks (101 ± 90 mL/(min*100g, P = .01), respectively. Relative to the baseline examination, mean diffusion increased from 0.68 ± 0.19 × 10(-3) s/mm(2) at baseline to 0.94 ± 0.24 × 10(-3) s/mm(2) after 3 weeks (P = .04), and 0.96 ± 0.40 × 10(-3) s/mm(2) after 8 weeks (P = .049). Both methods were able to correctly classify 9/10 patients as responder or nonresponder. CONCLUSION: ASL perfusion as well as DWI-MRI provide accurate, clinically relevant information regarding tumor viability and can predict response already early after therapy onset, as opposed to classical lesion size and MRI signal-intensity measurements.

Estimation of radiation exposure of 128-slice 4D-perfusion CT for the assessment of tumor vascularity.

OBJECTIVE: We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. MATERIALS AND METHODS: An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D-Perfusion-CT. Phantom measurements were performed on a 128-slice single-source scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). RESULTS: Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. CONCLUSION: Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans.