MRI analysis of uterine ischaemia as a form of non-target embolisation following uterine artery embolisation: incidence, extent and outcome.

AIM: To study the incidence, extent and fate of uterine ischaemia as one of the forms of non-target embolisation following uterine artery embolisation (UAE), as detected on immediate post-embolisation and contrast-enhanced magnetic resonance imaging (MRI) examinations at the 3-month follow-up. MATERIALS AND METHODS: A retrospective study was undertaken comprising 43 women (mean age: 44.8 ± 3.79 years). MRI was performed before, immediately after (within 6 h), and 3 months after successful UAE. Areas of uterine ischaemia were identified on immediate post-embolisation MRI as regions of newly developed (compared to pre-embolisation MRI) absent enhancement within the uterus not corresponding to the location of the leiomyoma. The volume of the ischaemic region was calculated using the formula (height × length × width × 0.523). RESULTS: Uterine ischaemia was encountered in 29 patients (67.44%). The mean volume of the ischaemic region immediately after UAE was 29.29 ± 19.15 ml (range: 7.36-87.71 ml). At 3-month follow-up, it was 0.35 ± 0.95 ml (range: 0-3.5 ml) with 25 (86%) patients showing complete resolution of the ischaemia. The mean reduction in the volume of the ischaemic region at the 3-month follow-up was 98.24 ± 5.72% (range: 72-100%). This volume reduction was statistically significant (p<0.0001). CONCLUSION: Uterine ischaemia as a form of non-target embolisation following UAE might be encountered in up to two thirds of patients. These ischaemic areas are significantly reduced at the 3-month follow-up with up to 86% of cases showing complete reversibility of the ischaemia.

Comparison of dual-energy CT-derived iodine content and iodine overlay of normal, inflammatory and metastatic squamous cell carcinoma cervical lymph nodes.

OBJECTIVES: To evaluate whether dual-energy computed tomography (DECT)-derived iodine content and iodine overlay could differentiate between normal, inflammatory and metastatic squamous cell carcinoma (SCC) cervical lymph nodes. METHODS: This study was approved by the institutional review board. Sixteen patients with normal lymph nodes, 20 patients with enlarged nodes draining deep cervical inflammations and 23 patients with pathologically proved metastatic SCC nodes who underwent contrast enhanced DECT were retrospectively identified. Iodine content and overlay of 36 normal, 43 inflammatory and 52 metastatic lymph nodes were calculated using circular regions of interest and compared among the three groups. A receiver operating characteristic (ROC) curve was used to determine the sensitivity and specificity of iodine content and overlay for diagnosis of metastatic nodes. RESULTS: Iodine content (mg/ml) was significantly lower for metastatic lymph nodes (2.34 ± 0.45) than for normal (2.86 ± 0.37) and inflammatory (3.53 ± 0.56) lymph nodes, P < 0.0001. Iodine overlay (HU) was also significantly lower for metastatic lymph nodes (47 ± 11.6) than normal (57.4 ± 8.2) and inflammatory nodes (69.3 ± 11.5), P < 0.0001. The areas under the ROC curve for iodine content and iodine overlay were 0.923 and 0.896. CONCLUSIONS: DECT-derived iodine content and overlay differ significantly among normal, inflammatory and metastatic SCC cervical lymph nodes. KEY POINTS: • Derived iodine content can be calculated from contrast-enhanced dual-energy CT. • Derived iodine content and iodine overlay could help characterise cervical lymph nodes. • Iodine parameters were significantly lower in metastatic lymph nodes than normal/inflammatory lymph nodes. • Iodine content appears more sensitive than iodine overlay for lymph node characterisation.

Role of uterine artery Doppler in the management of uterine leiomyoma by arterial embolization.

OBJECTIVES: To study Doppler changes in the uterine artery immediately following and 3 months after uterine artery embolization (UAE) and to test the feasibility of using uterine artery Doppler as a predictor of the predominant side of arterial supply to leiomyomas, amount of embolizing material needed and leiomyoma tumor volume at follow-up. METHODS: The study included 38 patients undergoing UAE for leiomyomas. Uterine artery Doppler was performed transabdominally before, within 6 hours after and 3 months after UAE to determine the peak systolic (PSV) and end-diastolic (EDV) velocities and resistance index (RI). Leiomyoma volume was measured using contrast-enhanced magnetic resonance imaging (MRI) before and 3 months after UAE. The predominant side of arterial supply to the leiomyoma was determined on digital subtraction angiography using the uterine artery diameter and tumor blush after contrast injection. For correlations with leiomyoma volume, the average PSV, EDV and RI of both sides was used, while for prediction of the predominant side of supply and for correlation with the amount of embolizing material needed, separate measurements from each side were used. RESULTS: Relative to the pre-embolization value, the uterine artery PSV and EDV were significantly reduced (P < 0.05) immediately following UAE, while the RI was significantly elevated (P < 0.05). For prediction of the predominant side of supply, the lowest RI showed the highest accuracy (81.6%). There was no significant correlation between the pre-embolization PSV, EDV or RI and the amount of embolizing material utilized. Immediately post-embolization EDV and RI values were statistically significantly correlated with the 3-month follow-up leiomyoma volume, with RI showing the strongest correlation (P = 0.0400 and 0.0002, rho = 0.34 and - 0.58, respectively). The leiomyoma volume was predicted to have reduced by 38-61% after 3 months if the immediate post-embolization average RI value was between 0.82 and 0.88. CONCLUSION: Pre-interventional Doppler assessment can be used to predict the predominant side of supply to leiomyomas but not the amount of embolizing material needed. Immediate post-interventional Doppler assessment can predict the leiomyoma volume after UAE.

Image quality and radiation dose of dual-energy CT of the head and neck compared with a standard 120-kVp acquisition.

BACKGROUND AND PURPOSE: DECT offers additional image datasets with potential benefits, but its use for H&N imaging is not justified unless image quality is preserved without increased radiation dose. The aim of this work was to compare image quality and radiation dose between a DE-derived WA image dataset and a standard SECT acquisition of the H&N. MATERIALS AND METHODS: Thirty-two patients underwent DECT of the H&N (tube voltages 80 and Sn140 kVp) and were compared with the last 32 patients who underwent standard SECT (120 kVp) on the same dual-source scanner. WA images from the 2 DE tubes were compared with images obtained with an SE mode. Radiation doses and attenuation measurements of the internal jugular vein, submandibular gland, and sternomastoid and tongue muscles were compared. Objective image noise was compared at 5 anatomic levels. Two blinded readers compared subjective image quality by using 5-point grading scales. RESULTS: CTDI(vol) was 12% lower with DE than with SECT, a difference of 1.5 mGy, (P < .0001). Objective noise was not significantly different between DE and SECT at any of the anatomic levels (P > .05). No significant differences in attenuation measurements were observed between DE and SECT (P > .05). No significant differences in subjective image quality scores were observed between DE and SECT at any of the 5 anatomic levels (P > .05). CONCLUSIONS: DE-derived WA images of the H&N are equivalent to standard SE acquisitions and thus can be used for routine diagnostic purposes. Multiple additional image datasets can be obtained with no radiation dose penalty.

[C-arm computed tomography for transarterial chemoperfusion and chemo-embolization of thoracic lesions]. / Transarterielle Chemoperfusion und -embolisation thorakaler Neoplasmen mittels C-Arm CT.

PURPOSE: To evaluate the role of C-arm CT for on-line fluoroscopy in regional transarterial chemoperfusion (TACP) and chemo-embolization (TPCE) of primary and secondary malignant thoracic lesions. MATERIALS AND METHODS: From September 2008 to March 2009 a total of 31 patients (20 males and 11 females, average age: 61.7 years, range 22-84 years) with 53 thoracic malignant lesions from different origins (primary or secondary pulmonary carcinoma n=37, pleural mesothelioma n=16) were treated with TACP or TPCE using flat-detector CT (FD-CT). C-arm CT of the latest generation was used to localize the lesion before local chemotherapy (Artis Zeego, Siemens, Erlangen). For TACP a 220 degrees rotation and a volume of 150 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 12 ml/s was used. For TPCE a volume of 75 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 3 ml/s was used. RESULTS: TPCE C-arm CT allowed the evaluation of the degree of perfusion of the tumor and the geographic areas of enhancement correlated with the post-interventional lipiodol uptake in MSCT. In TACP the intercostal arteries involved could be visualized and in 30% of interventions the catheter had to be repositioned for the following intervention. CONCLUSION: C-arm CT provides additional information on the vascular characteristics and perfusion of pulmonary lesions resulting in a change of interventional strategy in a relevant number of patients.

[Retrospective 5-year analysis of MR-guided biopsies in a low-field MR system]. / Retrospektive Analyse der 5-Jahres-Ergebnisse von MRT-gesteuerten Biopsien im Niederfeldsystem.

PURPOSE: The purpose of this study was to evaluate the safety and clinical value of MR-guided biopsies in an open 0.2 T low-field system. MATERIALS AND METHODS: A total of 322 patients with suspicious lesions of different body regions were biopsied in a low-field MRI system (0.2 T, Concerto, Siemens). The procedures were guided using T 1-weighted Flash sequences (TR/TE = 100/9; 70 degrees). The lesions were repeatedly biopsied using the coaxial technique with a 15-gauge (diameter 2 mm) puncture needle. Complications and biopsy findings were analyzed retrospectively. RESULTS: In all cases the biopsy procedures were successfully performed with MR guidance. In 298 patients diagnosis was able to be confirmed on the basis of the probes. The clinical follow-up showed that in 24 patients the lesions were missed by MR-guided biopsy. From this a sensitivity of 86%, a specificity of 87% and an accuracy of 93% were calculated. In two patients major complications were observed (morbidity rate 0.6 %). CONCLUSION: MR-guided biopsy can be performed safely and precisely in a low-field MR system and are a supplement to US or CT-guided biopsies.

Acute myocarditis in a rat model: late gadolinium enhancement with histopathological correlation.

The aim of the current study was to use an established animal model of autoimmune myocarditis and to judge the ability of cardiovascular MRI (CMR) in quantitatively measuring the extent of myocardial involvement compared with histopathological measurement of severity and extent. Experimental autoimmune myocarditis (EAM) was induced in 10 male Lewis rats. On day 21, all animals were investigated by CMR to measure the extent of late gadolinium enhancement (LGE). Subsequently, histopathological evaluation of the entire heart was performed. All animals of the experimental group fulfilled histopathological criteria of myocarditis, revealing necrosis in seven of eight cases. At reduced heart rate, area of LGE correlated highly with histologically proven area of myocarditis (r = 0.80-0.87, p < 0.05). LGE was mainly located in the anterior (range 50-62.5%) and lateral (range 62.5-75%) left ventricular wall and septum (range 25-50%) with a midwall to subepicardial accentuation. The LGE pattern found by CMR can be regarded as suggestive of EAM. With cellular necrosis being the main mechanism for LGE we were able to show high correlations between CMR examination results and histopathologically proven areas of myocarditis. Thus we think the current animal model can provide the opportunity for further fundamental research into myocarditis.