The Accuracy of On-Call CT Reporting in Teleradiology Networks in Comparison to In-House Reporting.

(1) Background: We aimed to compare the accuracy of after-hours CT reports created in a traditional in-house setting versus a teleradiology setting by assessing the discrepancy rates between preliminary and final reports. (2) Methods: We conducted a prospective study to determine the number and severity of discrepancies between preliminary and final reports for 7761 consecutive after-hours CT scans collected over a 21-month period. CT exams were performed during on-call hours and were proofread by an attending the next day. Discrepancies between preliminary and gold-standard reports were evaluated by two senior attending radiologists, and differences in rates were assessed for statistical significance. (3) Results: A total of 7209 reports were included in the analysis. Discrepancies occurred in 1215/7209 cases (17%). Among these, 433/7209 reports (6%) showed clinically important differences between the preliminary and final reports. A total of 335/5509 of them were in-house reports (6.1%), and 98/1700 were teleradiology reports (5.8%). The relative frequencies of report changes were not significantly higher in teleradiology. (4) Conclusions: The accuracy of teleradiology reports was not inferior to that of in-house reports, with very similar clinically important differences rates found in both reporting situations.

SHIP-MR and Radiology: 12 Years of Whole-Body Magnetic Resonance Imaging in a Single Center.

The Study of Health in Pomerania (SHIP), a population-based study from a rural state in northeastern Germany with a relatively poor life expectancy, supplemented its comprehensive examination program in 2008 with whole-body MR imaging at 1.5 T (SHIP-MR). We reviewed more than 100 publications that used the SHIP-MR data and analyzed which sequences already produced fruitful scientific outputs and which manuscripts have been referenced frequently. Upon reviewing the publications about imaging sequences, those that used T1-weighted structured imaging of the brain and a gradient-echo sequence for R2* mapping obtained the highest scientific output; regarding specific body parts examined, most scientific publications focused on MR sequences involving the brain and the (upper) abdomen. We conclude that population-based MR imaging in cohort studies should define more precise goals when allocating imaging time. In addition, quality control measures might include recording the number and impact of published work, preferably on a bi-annual basis and starting 2 years after initiation of the study. Structured teaching courses may enhance the desired output in areas that appear underrepresented.

Randomized, Double-Blind Study Comparing Patient Comfort and Safety Between Iodixanol 320 mg I/mL and Iopamidol 370 mg I/mL in Patients Undergoing Peripheral Arteriography - The COMFORT II Trial.

BACKGROUND: Numerous clinical trials conducted 10-20 years ago evaluated contrast-induced discomfort. It is unknown whether those data are applicable to current-day clinical practice. This study was performed to provide contemporary contrast-induced patient discomfort data obtained during peripheral arteriography procedures using iso-osmolar iodixanol 320 mg I/mL, compared to low-osmolar iopamidol 370 mg I/mL. METHODS AND RESULTS: Patients receiving iodixanol or iopamidol reported discomfort (heat, coldness, or pain) using a 10-point scale, which was converted to intensity categories: 0 = none; 1-3 = mild; 4-7 = moderate; and 8-10 = severe. Image diagnostic quality was assessed. Patients receiving iodixanol (n = 127; 61% male; mean age, 64 years) had less moderate/severe discomfort (67.7% vs 84.0%; P=.01) than those receiving iopamidol (n = 126; 64% male; mean age, 62 years), with pain contributing predominantly (7.3% vs 44.0%; P<.001) for all injection scores. Patients receiving iodixanol experienced less severe discomfort (16.9% vs 46.4%; P<.001), heat (15.3% vs 36.8%; P<.001), and pain (2.4% vs 23.2%; P<.001) for all injections, compared with patients receiving iopamidol. Image quality was rated as excellent in most patients (iodixanol 86.5% vs iopamidol 82.4%; P=.57). Treatment-emergent adverse events were similar between groups (iodixanol 18.9% vs iopamidol 11.9%; P=.16). CONCLUSIONS: Iodixanol injections induced significantly less moderate/severe and severe patient discomfort, heat, or pain than iopamidol, with pain contributing the most. Discomfort did not affect image quality.

Gd-EOB-DTPA-enhanced MR guidance in thermal ablation of liver malignancies.

OBJECTIVE: To evaluate the potency of Gd-EOB-DTPA to support hepatic catheter placement in laser ablation procedures by quantifying time-dependent delineation effects for instrumentation and target tumor within liver parenchyma. Monitoring potential influence on online MR thermometry during the ablation procedure is a secondary aim. MATERIALS AND METHODS: 30 cases of MR-guided laser ablation were performed after i.v. bolus injection of gadoxetic acid (0.025 mmol/Kg Gd-EOB-DTPA; Bayer Healthcare, Berlin, Germany). T1-weighted GRE sequences were used for applicator guidance (FLASH 3D) in the catheter placement phase and for therapy monitoring (FLASH 2D) in the therapy phase. SNR and consecutive CNR values were measured for elements of interest plotted over time both for catheter placement and therapy phase and compared with a non-contrast control group of 19 earlier cases. Statistical analysis was realized using the paired Wilcoxon test. RESULTS: Sustainable signal elevation of liver parenchyma in the contrast-enhanced group was sufficient to silhouette both target tumor and applicator against the liver. Differences in time dependent CNR alteration were highly significant between contrast-enhanced and non-contrast interventions for parenchyma and target on the one hand (p = 0.020) and parenchyma and instrument on the other hand (p = 0.002). Effects lasted for the whole procedure (monitoring up to 60 min) and were specific for the contrast-enhanced group. Contrasting maxima were seen after median 30 (applicator) and 38 (tumor) minutes, in the potential core time of a multineedle procedure. Contrast influence on T1 thermometry for real-time monitoring of thermal impact was not significant (p = 0.068-0.715). CONCLUSION: Results strongly support anticipated promotive effects of Gd-EOB-DTPA for MR-guided percutaneous liver interventions by proving and quantifying the delineating effects for therapy-relevant elements in the procedure. Time benefit, cost effectiveness and oncologic outcome of the described beneficiary effects will have to be part of further investigations.

PRFS-based MR thermometry versus an alternative T1 magnitude method--comparative performance predicting thermally induced necrosis in hepatic tumor ablation.

OBJECTIVE: To compare the accuracy of a semi-quantitative proton resonance frequency shift (PRFS) thermal mapping interface and an alternative qualitative T1 thermometry model in predicting tissue necrosis in an established routine setting of MRI-guided laser ablation in the human liver. MATERIALS AND METHODS: 34 cases of PRFS-guided (GRE) laser ablation were retrospectively matched with 34 cases from an earlier patient population of 73 individuals being monitored through T1 magnitude image evaluation (FLASH 2D). The model-specific real-time estimation of necrotizing thermal impact (above 54 °C zone and T1 signal loss, respectively) was correlated in size with the resulting necrosis as shown by lack of enhancement on the first-day contrast exam (T1). Matched groups were compared using the Mann-Whitney test. RESULTS: Online PRFS guidance was available in 33 of 34 cases. Positive size correlation between calculated impact zone and contrast defect at first day was evident in both groups (p < 0.0004). The predictive error estimating necrosis was median 21% (range 1 %-52%) in the PRFS group and 61 % (range 22-84%) in the T1 magnitude group. Differences in estimating lethal impact were significant (p = 0.004), whereas the real extent of therapy-induced necrosis showed no significant difference (p > 0.28) between the two groups. CONCLUSION: PRFS thermometry is feasible in a clinical setting of thermal hepatic tumor ablation. As an interference-free MR-tool for online therapy monitoring its accuracy to predict tissue necrosis is superior to a competing model of thermally induced alteration of the T1 magnitude signal.

Automated prostate segmentation in whole-body MRI scans for epidemiological studies.

The whole prostatic volume (PV) is an important indicator for benign prostate hyperplasia. Correlating the PV with other clinical parameters in a population-based prospective cohort study (SHIP-2) requires valid prostate segmentation in a large number of whole-body MRI scans. The axial proton density fast spin echo fat saturated sequence is used for prostate screening in SHIP-2. Our automated segmentation method is based on support vector machines (SVM). We used three-dimensional neighborhood information to build classification vectors from automatically generated features and randomly selected 16 MR examinations for validation. The Hausdorff distance reached a mean value of 5.048 ± 2.413, and a mean value of 5.613 ± 2.897 compared to manual segmentation by observers A and B. The comparison between volume measurement of SVM-based segmentation and manual segmentation of observers A and B depicts a strong correlation resulting in Spearman's rank correlation coefficients (ρ) of 0.936 and 0.859, respectively. Our automated methodology based on SVM for prostate segmentation can segment the prostate in WBI scans with good segmentation quality and has considerable potential for integration in epidemiological studies.

Teleradiology from the provider's perspective-cost analysis for a mid-size university hospital.

OBJECTIVES: Real costs of teleradiology services have not been systematically calculated. Pricing policies are not evidence-based. This study aims to prove the feasibility of performing an original cost analysis for teleradiology services and show break-even points to perform cost-effective practice. METHODS: Based on the teleradiology services provided by the Greifswald University Hospital in northeastern Germany, a detailed process analysis and an activity-based costing model revealed costs per service unit according to eight examination categories. The Monte Carlo method was used to simulate the cost amplitude and identify pricing thresholds. RESULTS: Twenty-two sub-processes and four staff categories were identified. The average working time for one unit was 55 (x-ray) to 72 min (whole-body CT). Personnel costs were dominant (up to 68 %), representing lower limit costs. The Monte Carlo method showed the cost distribution per category according to the deficiency risk. Avoiding deficient pricing by a likelihood of 90 % increased the cost of a cranial CT almost twofold as compared with the lower limit cost. CONCLUSIONS: Original cost analysis is possible when providing teleradiology services with complex statutory requirements in place. Methodology and results provide useful data to help enhance efficiency in hospital management as well as implement realistic reimbursement fees. KEY POINTS: • Analysis of original costs of teleradiology is possible for a providing hospital • Results discriminate pricing thresholds and lower limit costs to perform cost-effective practice • The study methods represent a managing tool to enhance efficiency in providing facilities • The data are useful to help represent telemedicine services in regular medical fee schedules.

Technical and clinical outcome of Talent versus Endurant endografts for endovascular aortic aneurysm repair.

OBJECTIVE: The technical evolution of endografts for the interventional management of infrarenal abdominal aortic aneurysms (AAA) has allowed a continuous expansion of indications. This study compares the established Talent endograft with its successor, the Endurant endograft, taking individual aortoiliac anatomy into account. METHODS: From June 2007 to December 2010, 35 patients with AAA were treated with a Talent endograft (33 men) and 36 patients with an Endurant endograft (34 men). Aortoiliac anatomy was evaluated in detail using preinterventional computed tomography angiography. The 30-day outcome of both groups were compared regarding technical and clinical success as well as complications including endoleaks. RESULTS: The Endurant group included more patients with unfavorable anatomy (kinking of pelvic arteries, p = 0.017; shorter proximal neck, p = 0.084). Primary technical success was 91.4% in the Talent group and 100% in the Endurant group (p = 0.115). Type 1 endoleaks occurred in 5.7% of patients in the Talent group and in 2.8% of those in the Endurant group (p = 0.614). Type 3 endoleaks only occurred in the Talent group (2.9% of patients; p = 0.493). Type 2 endoleaks were significantly less common in the Endurant group than in the Talent group (8.3% versus 28.6%; p = 0.035). Rates of major and minor complications were not significantly different between both groups. Primary clinical success was significantly better in the Endurant group (97.2%) than in the Talent group (80.0%) (p = 0.028). CONCLUSION: Endurant endografts appear to have better technical and clinical outcome in patients with difficult aortoiliac anatomy, significantly reducing the occurrence of type 2 endoleaks.

A pilot study for clinical feasibility of the near-harmonic 2D referenceless PRFS thermometry in liver under free breathing using MR-guided LITT ablation data.

OBJECTIVES: The conventional implementations of proton resonance frequency shift (PRFS) magnetic resonance thermometry (MRT) require the subtraction of single or multiple temporal references, a motion sensitive critical feature. A pilot study was conducted here to investigate the clinical feasibility of near-harmonic two-dimensional (2D) referenceless PRFS MRT, using patient data from MR-guided laser ablation of liver malignancies. METHODS: PRFS MRT with respiratory-triggered multi-slice gradient-recalled (GRE) acquisition was performed under free breathing in six patients. The precision of the novel referenceless MRT was compared with the reference phase subtraction. Coupling the referenceless MRT with a model-based, real-time compatible regularisation algorithm was also investigated. RESULTS: The precision of MRT was improved by a factor of 3.3 when using the referenceless method as compared to the reference phase subtraction. The approach combining referenceless PRFS MRT and model-based regularisation yielded an estimated precision of 0.7° to 2.1°C, resulting in millimetre-range agreement between the calculated thermal dose and the 24 h post-treatment unperfused regions in liver. CONCLUSIONS: The application of the near-harmonic 2D referenceless MRT method was feasible in a clinical scenario of MR-guided laser-induced thermal therapy (LITT) ablation in liver and permitted accurate prediction of the thermal lesion under free breathing in conscious patients, obviating the need for a controlled breathing under general anaesthesia.

Selective microcoil embolization of arterial gastrointestinal bleeding in the acute situation: outcome, complications, and factors affecting treatment success.

OBJECTIVES: To evaluate microcoil embolization in the interventional treatment of acute upper and lower gastrointestinal bleeding. PATIENTS AND METHODS: Forty-four patients (29 men, 15 women) with active arterial gastrointestinal bleeding were treated with microcoil embolization. The analysis included technical/clinical success, morbidity, mortality, and intervention-related mortality. Age, sex, underlying malignant disease, number of embolizations, preinterventional and postinterventional hemoglobin levels, blood products administered peri-interventionally, amount of embolization material used, duration of fluoroscopy, and use of contrast medium were evaluated for possible effects on technical and clinical success. RESULTS: The primary technical success rate of microcoil embolization for acute gastrointestinal bleeding was 88.6% with a clinical success rate of 56.8%. Minor and major complications occurred in 13.6 and 18.2% of patients, respectively. Intervention-associated mortality, due to intestinal ischemia, accounted for 4.6% of the total 18.2% mortality rate. Patients with technically successful embolization had a statistically significant increase in hemoglobin (P<0.01) after the intervention and a decrease in need for packed red blood cells, (P<0.01), fresh frozen plasma (P<0.01), and coagulation products (P<0.01). A smaller postinterventional fresh frozen plasma requirement was associated with a better clinical outcome (P=0.02). CONCLUSION: Microcoil embolization of arterial gastrointestinal bleeding in the acute situation has a high-technical success rate. The number of transfusions required before and after the intervention has no significant effect on technical success. Postinterventional fresh frozen plasma demand negatively correlates with clinical success.

Residual tumor after laser ablation of human non-small-cell lung cancer demonstrated by ex vivo staining: correlation with invasive temperature measurements.

OBJECT: Histology is the gold standard for confirming thermally induced necrosis. Generally, however, no specimen is obtained from thermal ablation therapy for pathological examination. The aim of this study was to provide evidence for the relationship between temperatures reached and resulting tissue coagulation during laser ablation in a near-physiological ex vivo lung tumor model by combining viability staining and direct temperature measurement. MATERIALS AND METHODS: In all, 17 human lung specimens with primary non-small-cell lung cancer (NSCLC) were examined in this study. Organs were resected with curative intent from patients of either gender (5 female, 12 male) with an average age of 65 years (51-78). Here, 11/17 specimens were subjected to interstitial laser thermal ablation in an ex vivo lung perfusion and ventilation model after surgery. A control group of 6/17 specimens was tested for viability without laser ablation. Tissue temperature was measured invasively in real-time during the ablation process using thermocouples. Afterwards, representative slices of all 17 specimens were tested for viability with triphenyltetrazolium chloride (TTC). Maximum tissue temperature Tmax[°C] measured at a distance of 10 and 20 mm from the laser tip and time of temperature exposure were correlated with the diameter of the induced coagulation as ascertained with viability staining. CH evaluated the results. RESULTS: Mean maximum temperature was 75.9°C ± 14.4°C at a distance of 10 mm from the laser tip and 50.3°C ± 14.6°C at a distance of 20 mm, respectively. The mean distance between the coagulation margin and the laser tip was 17.8 mm ± 7.3 mm. CONCLUSION: We found that coagulation size correlated positively with temperature. There was a clear trend towards the correlation of time over 44°C and ablation depth. Maximum temperatures did not significantly correlate with coagulation size. Laser ablation of lung tumors using the IHLP (isolated human lung perfusion) model represents a possible method for evaluating ex vivo the interrelationships of temperature, time of temperature exposure, and resulting coagulation.

Nodular hemangiomatosis of pleura and peritoneum.

Multiple, simultaneously occurring hemangiomas in one or more organs are known as hemangiomatosis syndromes in the context of phacomatosis manifesting in childhood. Nevertheless, hemangiomas of the serous membranes are extremely rare and often present as solitary lesions. We report the case of an elderly patient who suffered from diffuse hemangiomatosis of the visceral peritoneum and pleura and deceased due to acute respiratory distress syndrome following persistent and unmanageable pulmonary hemorrhage. We present an unusual case of a disseminated but histologically benign appearing hemangiomatosis of the serous membranes.

Clinical evaluation of MR temperature monitoring of laser-induced thermotherapy in human liver using the proton-resonance-frequency method and predictive models of cell death.

PURPOSE: To assess the feasibility, precision, and accuracy of real-time temperature mapping (TMap) during laser-induced thermotherapy (LITT) for clinical practice in patients liver with a gradient echo (GRE) sequence using the proton resonance frequency (PRF) method. MATERIALS AND METHODS: LITT was performed on 34 lesions in 18 patients with simultaneous real-time visualization of relative temperature changes. Correlative contrast-enhanced T1-weighted magnetic resonance (MR) images of the liver were acquired after treatment using the same slice positions and angulations as TMap images acquired during LITT. For each slice, TMap and follow-up images were registered for comparison. Afterwards, segmentation based on temperature (T) >52°C on TMap and based on necrosis seen on follow-up images was performed. These segmented structures were overlaid and divided into zones where the TMap was found to either over- or underestimate necrosis on the postcontrast images. Regions with T>52°C after 20 minutes were defined as necrotic tissue based on data received from two different thermal dose models. RESULTS: The average intersecting region of TMap and necrotic zone was 87% ± 5%, the overestimated 13% ± 4%, and the underestimated 13% ± 5%. CONCLUSION: This study demonstrates that MR temperature mapping appears reasonably capable of predicting tissue necrosis on the basis of indicating regions having greater temperatures than 52°C and could be used to monitor and adjust the thermal therapy appropriately during treatment.

Assessing early vascular changes and treatment response after laser-induced thermotherapy of pulmonary metastases with perfusion CT: initial experience.

OBJECTIVE: The objective of our study was to use perfusion CT to prospectively monitor early vascular changes in tumor perfusion of pulmonary metastases after laser-induced thermotherapy (LITT) and to determine whether any of the perfusion parameters would predict technical success after therapy. SUBJECTS AND METHODS: Twelve patients with histologically proven pulmonary metastases undergoing LITT were enrolled prospectively in this study. Perfusion CT was performed before treatment, 1 day after treatment, and 4-6 weeks after therapy, and tumor blood flow, tumor blood volume (TBV), mean transit time (MTT), and permeability of the capillary wall surface (capillary permeability-surface product) in 22 pulmonary metastases were calculated. Perfusion parameters at baseline and after LITT were compared. Measurement of tumor diameter on long-term follow-up CT was the gold standard with which perfusion CT results were compared for local control. RESULTS: Median tumor blood flow, TBV, and capillary permeability-surface product had decreased significantly from baseline by 43%, 61%, and 73%, respectively, 1 day after LITT. Perfusion parameters obtained 4-6 weeks after treatment had not changed significantly compared with those obtained 1 day after therapy. There seems to be a good correlation between changes in perfusion CT parameters 1 day after therapy and local outcome, according to the Response Evaluation Criteria in Solid Tumors (RECIST), 1 year after therapy. CONCLUSION: Perfusion CT of pulmonary metastases has potential in the assessment of early vascular changes that result from LITT and predicting technical success immediately after treatment. Tumors with perfusion measurements that had not changed after therapy indicated progressive disease.

Laser ablation of metastatic lesions of the lung: long-term outcome.

OBJECTIVE: Pulmonary metastatic lesions are present in 20-54% of all patients who die of cancer. Surgical studies have shown that local management of distant tumor metastasis as part of multimodal cancer therapy improves survival. Minimally invasive procedures such as thermal ablation are still to prove their clinical relevance. The aim of this study was to monitor therapeutic outcome and long-term results after percutaneous laser-induced thermal ablation. SUBJECTS AND METHODS: Sixty-four patients with metastasis to the lung underwent laser-induced thermal ablation in an ongoing prospective study. A total of 129 percutaneous procedures were performed to manage a total of 108 lung lesions. The median tumor size was 2.0 cm (range, 0.4-8.5 cm). Adequate management of all known individual tumor correlates was critical for definitive patient therapy. The Kaplan-Meier method was used to calculate survival and recurrence rates. RESULTS: Definitive management of initial pulmonary disease was achieved in 31 of 64 patients. The 1-, 2-, 3-, 4-, and 5-year survival rates after ablative therapy were 81%, 59%, 44%, 44%, and 27%. The median progression-free interval was 7.4 months. There were no therapy-related deaths. Pneumothorax occurred in 38% of the patients, necessitating periprocedural drainage in 5% of all cases. Parenchymal bleeding (13% of cases) always was self-limited. CONCLUSION: Laser ablative therapy for pulmonary metastasis is a promising option in multimodal cancer therapy. The procedure is safe and effective. The initial clinical outcome data strongly suggest that this technique has the potential to improve survival among selected patients.

Laser ablation of liver metastases from colorectal cancer with MR thermometry: 5-year survival.

PURPOSE: To determine technical success, technique effectiveness, complications, and survival after laser ablation of liver metastases from colorectal cancer. MATERIALS AND METHODS: Eighty-seven consecutive patients (65 men and 22 women; mean age, 62.8 years) with 180 liver metastases from colorectal carcinoma were included between 1998 and 2005. They underwent laser ablation with magnetic resonance (MR) thermometry in 170 sessions. Indications for laser ablation were locally unresectable tumors (16.1%), metastases in both liver lobes (34.5%), and refusal of surgery and/or general contraindications to surgery (49.4%). Technical success, technique effectiveness, and complication and survival rates were evaluated retrospectively. RESULTS: Technical success was achieved in 178 of 180 sessions (99%). Follow-up after 24-48 hours demonstrated an effectiveness rate of 85.6%. Local tumor progression rate was 10% after 6 months. Major complications included large pleural effusion, large subcapsular hematoma, abscess, large pneumothorax, pleuritis with fever, intrahepatic hemorrhage, and biloma. Mean survival from the time of diagnosis of the primary tumor was 50.6 months for all patients treated (95% CI, 44.9-56.3 months). Median survival time was 54 months and survival rates were 95.7% at 1 year, 86.2% at 2 years, 72.4% at 3 years, 50.1% at 4 years, and 33.4% at 5 years. The mean survival time after the first treatment was 31.1 months (95% CI, 26.9-35.3 months). CONCLUSIONS: Laser ablation of liver metastases of colorectal cancer with MR thermometry appears safe and efficacious. Although the results are encouraging, direct comparison with other ablative modalities in a prospective clinical trial would be necessary to definitely show one modality is superior.

Three-dimensional gradient-echo imaging for percutaneous MR-guided laser therapy of liver metastasis.

PURPOSE: To evaluate the use of three-dimensional (3D) gradient-echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR-guided catheter placement for laser therapy of liver metastases. MATERIALS AND METHODS: Thirty-four patients were included. A total of 122 MR-guided percutaneous punctures of 67 liver metastases were performed on a 1.5T scanner (Symphony and Sonata; Siemens, Erlangen, Germany) using a 5.5F microcatheter system and titanium needle (Monocath; MeoMedical, Augsburg, Germany). In 88 of 122 procedures, a 2D fast low-angle shot (FLASH) T1-weighted GRE breath-hold sequence was acquired in the axial plane and if necessary in a second plane. Sequences were acquired and reviewed using the panel in the control room. In 34 of 122 procedures a 3D FLASH T1-weighted fat-saturated GRE (volume-interpolated breath-hold examination (VIBE)) sequence was acquired in the axial plane only. Acquisition and 3D review were controlled under sterile conditions with a panel inside the examination room (Syngo; Siemens). RESULTS: The 3D FLASH sequence significantly decreased the mean number of acquisitions needed to place the microcatheter with the titanium needle in the metastasis compared to interventions with the 2D FLASH sequence (2.9 +/- 0.83 vs. 4.4 +/- 1.63). With 2D FLASH imaging, acquisition in a second plane was necessary in 78 instances (20% of acquired 2D sequences) to ensure adequate positioning of the device during the procedure. The artifact caused by the titanium needle was smaller with the 3D FLASH sequence. The conspicuity of liver metastases and morphology (liver edge and vessels) was acceptable with both sequences. The 3D FLASH sequence improved differentiation when two to four titanium needles were inserted, due to smaller susceptibility artifacts caused by the needles. CONCLUSION: 3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis.

Laser ablation of lung metastases: results according to diameter and location.

Lung tumour ablation with a thin-calibre laser applicator system was evaluated. We quantified feasibility, technical success and complication rates in relation to lesion diameter and location. Forty-two patients with 64 lung tumours were treated (39 patients with metastases and three with primary tumours). Mean follow-up was 7.6 months (range 6 weeks to 39 months). Eighty-six percent of treatments were technically successful in the first session. Pneumothorax was the main complication and occurred in 50% of the first 20 patients and in 35% of the rest. Two patients required a chest tube. Fourteen lesions were central and 50 were peripheral. It took several weeks for the effect of the therapy to become apparent on follow-up CT. Thirty-nine percent of all lesions increased in size immediately after treatment. Gross reduction in size with scar formation was seen in 50% of the lesions and cavitation in 13%. Local tumour control was achieved in 51 lesions. Progression after therapy was seen in 9% of lesions <1.5 cm but in more than 11% of larger lesions. Progression was also more frequent in lesions located in the basal parts of the lung (47%). Sixteen patients died due to systemic progression. Our results suggest that successful laser ablation of lung lesions is possible with a miniaturized applicator.