Radiological and histological findings in ancient salt mummies from the salt mine of Douzlakh, Iran.

Computed tomography studies and histological analyses were performed on the mummified remains found in the Chehrabad salt mine in northwestern Iran. The ancient salt mummies are dated to the Achaemenid (550-330 BC) and Sassanid (3rd-7th century AD) time period and died in mining incidents. The aim of the study was to describe the radiological and histological findings of several ancient Iranian salt mummies with special interest in pathological and postmortem changes. The mummified remains show multiple traumatic alterations, such as fractures and signs of massive compression. Histological analyses can clearly differentiate soft tissue, however the preservation status is variable. These Iranian salt mummies are a rare example of the ancient Iranian population. The soft tissue and organs are well preserved, however in different degrees due to the varying conditions.

MRI texture analysis for differentiation of malignant and benign hepatocellular tumors in the non-cirrhotic liver.

PURPOSE: To find potentially diagnostic texture analysis (TA) features and to evaluate the diagnostic accuracy of two-dimensional (2D) magnetic resonance (MR) TA for differentiation between hepatocellular carcinoma (HCC) and benign hepatocellular tumors in the non-cirrhotic liver in an exploratory MR-study. MATERIALS AND METHODS: 108 non-cirrhotic patients (62 female; 41.5 ± 18.3 years) undergoing preoperative contrast-enhanced MRI were retrospectively included in this multi-center-study. TA including gray-level histogram, co-occurrence and run-length matrix features (total 19 features) was performed by two independent readers. Native fat-saturated-T1w and T2w as well as arterial and portal-venous post contrast-enhanced 2D-image-slices were assessed. Conventional reading was performed by two separate independent readers. Differences in TA features between HCC and benign lesions were investigated using independent sample t-tests. Logistic regression analysis was performed to obtain the optimal number/combination of TA-features and diagnostic accuracy of TA analysis. Sensitivity and specificity of the better performing radiologist were compared to TA analysis. RESULTS: The highest number of significantly differing TA-features (n = 5) was found using the arterial-phase images including one gray-level histogram (skewness, p = 0.018) and four run-length matrix features (all, p < 0.02). The optimal binary logistic regression model for TA-features of the arterial-phase images contained 13 parameters with an accuracy of 84.5% (sensitivity 84.1%, specificity 84.9%) and area-under-the-curve of 0.92 (95%-confidence-interval 0.85-0.98) for diagnosis of HCC. Conventional reading yielded a significantly lower sensitivity (63.6%, p = 0.027) and no significant difference in specificity (94.6%, p = 0.289) at best. CONCLUSION: 2D-TA of MR images is a feasible objective method that may help to distinguish HCC from benign hepatocellular tumors in the non-cirrhotic liver. Most promising results were found in TA features in the arterial phase images.

Computed tomography perfusion imaging for monitoring transarterial chemoembolization of hepatocellular carcinoma.

PURPOSE: To prospectively monitor changes in tumor perfusion of hepatocellular carcinoma (HCC) in response to doxorubicin-eluted bead based transarterial chemoembolization (DEB-TACE) using perfusion-CT (P-CT). METHODS AND MATERIALS: 24 patients (54-79 years) undergoing P-CT before and shortly after DEB-TACE of HCC were prospectively included in this dual-center study. Two readers determined arterial-liver-perfusion (ALP, mL/min/100mL), portal-venous-perfusion (PLP, mL/min/100mL) and the hepatic-perfusion-index (HPI, %) by placing matched regions-of-interests within each HCC before and after DEB-TACE. Imaging follow-up was used to determine treatment response and to distinguish complete from incomplete responders. Performance of P-CT for prediction and early response assessment was determined using receiver-operating-characteristics curve analysis. RESULTS: Interreader agreement was fair to excellent (ICC, 0.716-0.942). PLP before DEB-TACE was significantly higher in pre-treated vs non-treated lesions (P<0.05). Mean changes of ALP, PLP and HPI from before to after DEB-TACE were -55%, +24% and -27%. ALP and HPI after DEB-TACE were correlating with response-grades (r=0.45/0.48; both, p<0.04), showing an area-under-the-curve (AUC) of 0.74 and 0.80 respectively for identification of complete response. CONCLUSION: High arterial and low portal-venous perfusion of HCC early after DEB-TACE indicates incomplete response with good diagnostic accuracy.

Arterio-portal shunts in the cirrhotic liver: perfusion computed tomography for distinction of arterialized pseudolesions from hepatocellular carcinoma.

OBJECTIVES: To determine perfusion computed tomography (P-CT) findings for distinction of arterial pseudolesions (APL) from hepatocellular carcinoma (HCC) in the cirrhotic liver. METHODS: 32 APL and 21 HCC in 20 cirrhotic patients (15 men; 65 ± 10 years), who underwent P-CT for evaluation of HCC pre- (N = 9) or post- (N = 11) transarterial chemoembolization, were retrospectively included using CT follow-up as the standard of reference. All 53 lesions were qualitatively (visual) and quantitatively (perfusion parameters) analysed according to their shape (wedge, irregular, nodular), location (not-/adjunct to a fistula), arterial liver perfusion (ALP), portal venous liver perfusion (PLP), hepatic perfusion index (HPI). Accuracy for diagnosis of HCC was determined using receiver operating characteristics. RESULTS: 18/32 (56 %) APL were wedge shaped, 10/32 (31 %) irregular and 4/32 (12 %) nodular, while 11/21 (52 %) HCC were nodular or 10/21 (48 %) irregular, but never wedge shaped. Significant difference between APL and HCC was seen for lesion shape in pretreated lesions (P < 0.001), and for PLP and HPI in both pre- and post-treated lesions (all, P < 0.001). Diagnostic accuracy for HCC was best for combined assessment of lesion configuration and PLP showing an area under the curve of 0.901. CONCLUSION: Combined assessment of lesion configuration and portal venous perfusion derived from P-CT allows best to discriminate APL from HCC with high diagnostic accuracy. KEY POINTS: • Arterio-portal shunting is common in the cirrhotic liver, especially after local treatment. • Arterial pseudolesions (APL) due to shunting might mimic hepatocellular carcinoma (HCC). • Perfusion-CT allows for qualitative and quantitative assessment of liver lesions. • Lesion configuration fails to discriminate APL from HCC in locally treated patients. • Integration of quantitative perfusion analysis improves accuracy for diagnosis of HCC.

CT Perfusion for Early Response Evaluation of Radiofrequency Ablation of Focal Liver Lesions: First Experience.

PURPOSE: To investigate the value of perfusion CT (P-CT) for early assessment of treatment response in patients undergoing radiofrequency ablation (RFA) of focal liver lesions. METHODS AND MATERIALS: 20 consecutive patients (14 men; mean age 64 ± 14) undergoing P-CT within 24 h after RFA of liver metastases (n = 10) or HCC (n = 10) were retrospectively included. Two readers determined arterial liver perfusion (ALP, mL/min/100 mL), portal liver perfusion (PLP, mL/min/100 mL), and hepatic perfusion index (HPI, %) in all post-RFA lesions by placing a volume of interest in the necrotic central (CZ), the transition (TZ), and the surrounding parenchymal (PZ) zone. Patients were classified into complete responders (no residual tumor) and incomplete responders (residual/progressive tumor) using imaging follow-up with contrast-enhanced CT or MRI after a mean of 57 ± 30 days. Prediction of treatment response was evaluated using the area under the curve (AUC) from receiver operating characteristic analysis. RESULTS: Mean ALP/PLP/HPI of both readers were 4.8/15.4/61.2 for the CZ, 9.9/16.8/66.3 for the TZ and 20.7/29.0/61.8 for the PZ. Interreader agreement of HPI was fair for the CZ (intraclass coefficient 0.713), good for the TZ (0.813), and excellent for the PZ (0.920). For both readers, there were significant differences in HPI of the CZ and TZ between responders and nonresponders (both, P < 0.05). HPI of the TZ showed the highest AUC (0.911) for prediction of residual tumor, suggesting a cut-off value of 76 %. CONCLUSION: Increased HPI of the transition zone assessed with P-CT after RFA might serve as an early quantitative biomarker for residual tumor in patients with focal liver lesions.

Recent technological advances in computed tomography and the clinical impact therein.

Current technological advances in CT, specifically those with a major impact on clinical imaging, are discussed. The intent was to provide for both medical physicists and practicing radiologists a summary of the clinical impact of each advance, offering guidance in terms of utility and day-to-day clinical implementation, with specific attention to radiation dose reduction.