Image Quality Assessment of 2D versus 3D T2WI and Evaluation of Ultra-high b-Value (b=2,000 mm/s2) DWI for Response Assessment in Rectal Cancer.

AIM: The purpose of this IRB-approved, retrospective study was to compare image quality between 2D and high-resolution 3D, T2-weighted (T2WI) magnetic resonance imaging (MRI) sequences and to investigate the additional value of ultra-high b-value diffusion-weighted imaging (DWI; b=2,000 mm/s2) for both rectal cancer staging and evaluating treatment response. MATERIALS AND METHODS: From 12 February to 24 August 2016, 26 consecutive patients (22 males, four females; mean age: 61.9±14.0 years) with histologically-proven rectal cancer. In total 31 examinations [12 prior to and 19 after chemoradiation (CRT)] were included. The patients underwent pelvic MRI on a 3.0-T scanner (Magnetom Skyra, Erlangen, Germany). Three radiologists (3, 4, and 5 years of experience in MRI, respectively) independently assessed all images and rated the image quality of DWI (b=800 mm/s2), apparent diffusion coefficient map, DWI (b=2,000 mm/s2), 3D sagittal T2WI, 3D axial T2WI, 2D sagittal T2WI, and 2D axial T2WI of each patient, respectively. In addition, signal intensity ratios (SIR) were calculated between rectal cancer and obturator internus muscle (background) in all patients after CRT on DWI (b=2,000 mm/s2) and correlated with histopathological regression grade (RG). RESULTS: Tumor delineation was significantly better by 2D T2WI than 3D T2WI both before and after CRT (before CRT: Z=-3.2, p=0.02; after CRT: Z=-4.408, p<0.001; all: Z=-5.192; p<0.001) and was the preferred method, although image quality ratings were not significantly different (3D sagittal: 4.00±0.48; 2D sagittal: 4.03±0.34, p=0.713; 3D axial: 3.85±0.61, 2D axial: 3.78±0.64, p=0.537). Independent t-test showed significantly higher SIR between those with RG 1 or 2 (moderate response: mean score=2.02) and those with RG 3+4 (good response: mean score=0.8) (t=3.044, p=0.011). In those with RG 4 (complete response), SIR of b2000 was 0.946 compared to a 1.41 average of the whole cohort. In two patients, tumor was invisible on b2000 following CRT (RG 3 and 4, respectively). Interobserver agreement was mostly good (κ≥0.6) regarding image quality assessment, except for poor agreement (κ=0.4) in DWI (b2000) between the two less-experienced readers. CONCLUSION: In conclusion, 3D T2WI might be useful for evaluating response to neoadjuvant therapy in a comprehensive, cost-effective protocol, where 2D imaging seems to be preferable. In addition, DWI (b2000) may be beneficial in assessing both the primary and the residual tumor after CRT in rectal cancer and SIR may be helpful in assessing response to CRT.

Performance of a Robotic Assistance Device in Computed Tomography-Guided Percutaneous Diagnostic and Therapeutic Procedures.

PURPOSE: To evaluate a commercially available robotic assistance device for computed tomography-guided diagnostic and therapeutic interventions, compared to regular, manually performed CT scan-guided interventions in terms of precision, exposure to radiation to the patient and intervention time. MATERIALS AND METHODS: Over a period of 6 months, 55 consecutive patients were recruited and treated using robotic assistance and compared to a control group of 101 patients previously treated with a regular CT scan-guided, manual approach. Evaluated parameters were precision (deviation from planned target and number of needle replacements), radiation exposure to the patient and intervention time. Evaluations were performed with regard to complexity (in-plane vs out-of-plane interventions) and type of anesthesia (general vs local). RESULTS: Parameters related to precision were in general significantly better in the robotic assistance group (p < 0.01) with a mean deviation of 1.2 mm (± 1.6 mm) compared to 2.6 mm (± 1.1 mm) in the comparison group. Compared to manual procedure, the mean intervention time was reduced by 15 min (± 5.4 min) on average for an out-of-plane needle placement in the robotic group. There was no increase of exposure to radiation to the patient while radiation exposure for the physician was reduced to zero when the navigation system was used. CONCLUSION: Compared to manual placement, the use of a robotic assistance device in out-of-plane CT-guided interventions under general anesthesia allows for probe placement with high precision. Intervention time is reduced with no increase of exposure to radiation to the patient.

Parenchymal Liver Blood Volume and Dynamic Volume Perfusion CT Measurements of Hepatocellular Carcinoma in Patients Undergoing Transarterial Chemoembolization.

AIM: Prospective comparison of cone beam C-Arm CT based parenchymal liver blood volume (PLBV) and dynamic volume perfusion CT (dVPCT) measurements in patients with hepatocellular carcinoma (HCC) undergoing transarterial chemoembolisation (TACE) with drug-eluting beads (DEB). PATIENTS AND METHODS: In 16 patients, changes of PLBV and dVPCT measurements [arterial liver parenchyma (ALP); temporal maximum intensity projection (MIP); hepatic perfusion index (HPI); portal venous parenchyma] were correlated to one another and to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). RESULTS: After TACE, the following parameters showed a statistically significant change (p<0.05) in mean value: PLBV: -4.85 ml/100 ml, ALP: -4.14 ml/100 ml/min, MIP: -0.23 Houndsfield units, HPI: -5.39%, and mRECIST: -20.53 mm. Pre-to-post TACE differences in PLBV showed only weak to very weak correlation to dVPCT parameters (r2<0.24). CONCLUSION: Although PLBV and dVPCT parameters showed only a weak to very weak correlation, both methods validly assessed changes in arterial tumor vascularity after DEB TACE.

Incremental benefit of late gadolinium cardiac magnetic resonance imaging for risk stratification in patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) has a low risk for sudden cardiac death (SCD). The ESC clinical risk prediction model estimates the risk of SCD using clinical and echocardiographical parameters without taking into account cardiac magnetic resonance (CMR) parameters. Therefore, we compared the CMR characteristics of 149 patients with low, intermediate and high ESC risk scores. In these patients left and right ventricular ejection fraction and volumes were comparable. Patients with a high ESC risk score revealed a significantly higher extent of late gadolinium enhancement (LGE) compared to patients with intermediate or a low risk scores. During follow-up of 4 years an extent of LGE ≥20% identified patients at a higher risk for major adverse cardiac arrhythmic events in the low and intermediate ESC risk group whereas an extent of LGE <20% was associated with a low risk of major adverse cardiac arrhythmic events despite a high ESC risk score ≥6%. Hence, we hypothesize that the extent of fibrosis might be an additional risk marker.

Irreversible Electroporation for Surgical Renal Masses in Solitary Kidneys: Short-Term Interventional and Functional Outcome.

PURPOSE: To examine short-term outcomes and complications in patients with a solitary kidney treated with irreversible electroporation (IRE) for a potentially malignant renal mass. MATERIALS AND METHODS: Five patients (2 female, 3 male; mean age, 66 y) with 7 lesions who underwent IRE for renal tumors in a solitary kidney between August 2014 and August 2015 were retrospectively reviewed. Changes in signal intensity (SI) of the treated lesion were evaluated on contrast-enhanced magnetic resonance imaging. To evaluate functional outcome, creatinine levels and estimated glomerular filtration rate (eGFR) were compared vs baseline after 1 day, 2-7 days, 3-6 weeks, and 6-12 weeks after the intervention. RESULTS: Mean tumor diameter was 24.4 mm (range, 15-38 mm), with an average score of 7.7 (range, 4-9) per R.E.N.A.L. criteria (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines). There was a progressive, significant decrease in treated tumor SI on follow-up imaging (mean, 70%-82%), suggesting a treatment response rate of 100% at a mean follow-up of 6.4 months (range, 3-11 mo). Two minor acute complications (Society of Interventional Radiology class A) occurred: transient gross hematuria and stage I acute kidney failure. Overall, there was no significant decrease in eGFR (-2.75 mL/min) over 3 months, even though 1 patient's eGFR decreased from > 60 mL/min/1.73m(2) to 44 mL/min/1.73m(2). CONCLUSIONS: The data suggest that percutaneous IRE for renal mass in patients with a solitary kidney is safe and feasible. It may help to preserve renal function and offers promising short-term oncologic results.