Biomedical subjects

Jens Ricke

Publications and source records attributed to Jens Ricke.

At least 19 recordsLinked to original sources

PubMed2007

High-resolution MRI of the wrist and finger joints in patients with rheumatoid arthritis: comparison of 1.5 Tesla and 3.0 Tesla.

The goal of this study was to compare magnetic resonance (MR) image quality at different field strengths for evaluating lesions in wrist and finger joints of patients with rheumatoid arthritis (RA) in order to determine whether the higher field strength provides diagnostic gain. The hand mainly affected in 17 RA patients was examined at 1.5 Tesla (T) and 3.0 T with comparable MR imaging (MRI) protocols. MR images were reviewed twice by two experienced radiologists using the Rheumatoid Arthritis MRI Scoring System (RAMRIS) of the OMERACT (Outcome Measures in Rheumatoid Arthritis Clinical Trials) group. Image quality was rated on a five-point scale using Friedmann's test and Kendall's W-test for statistical analysis. Image comparison revealed better image quality at higher field strength. Image quality of T1-weighted images was rated 14-22% better at 3.0 T compared with 1.5 T by both readers. Moreover, the rating for the T2-weighted-images acquired at 3.0 T was one point better in the five-point scale used. Inter-reader correlation for image quality, bone erosions/defects, edema and synovitis ranged between 0.6 and 0.9 at 3.0 T and between 0.6 and 0.8 at 1.5 T. Intra-reader correlation for these parameters was high at 0.8-1.0. MRI image quality of RA hands is superior at 3.0 T, while an acceptable image quality is achieved at 1.5 T, which improves the evaluation of extent of bone edema, synovitis and identification of small bone erosions.

Adult↗

PubMed2006

In vivo assessment of the gastric mucosal tolerance dose after single fraction, small volume irradiation of liver malignancies by computed tomography-guided, high-dose-rate brachytherapy.

PURPOSE: The aim of this study was to assess the tolerance dose of gastric mucosa for single-fraction computed tomography (CT)-guided, high-dose-rate (HDR) brachytherapy of liver malignancies. METHODS AND MATERIALS: A total of 33 patients treated by CT-guided HDR brachytherapy of liver malignancies in segments II and/or III were included. Dose planning was performed upon a three-dimensional CT data set acquired after percutaneous applicator positioning. All patients received gastric protection post-treatment. For further analysis, the contours of the gastric wall were defined in every CT slice using Brachyvision Software. Dose-volume histograms were calculated for each treatment and correlated with clinical data derived from questionnaires assessing Common Toxicity Criteria (CTC). All patients presenting symptoms of upper GI toxicity were examined endoscopically. RESULTS: Summarizing all patients the minimum dose applied to 1 ml of the gastric wall (D(1 ml)) ranged from 6.3 to 34.2 Gy; median, 14.3 Gy. Toxicity was present in 18 patients (55%). We found nausea in 16 (69%), emesis in 9 (27%), cramping in 13 (39%), weight loss in 12 (36%), gastritis in 4 (12%), and ulceration in 5 patients (15%). We found a threshold dose D(1 ml) of 11 Gy for general gastric toxicity and 15.5 Gy for gastric ulceration verified by an univariate analysis (p = 0.01). CONCLUSIONS: For a single fraction, small volume irradiation we found in the upper abdomen a threshold dose D(1 ml) of 15.5 Gy for the clinical endpoint ulceration of the gastric mucosa. This in vivo assessment is in accordance with previously published tolerance data.

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PubMed2006

Image-guided micro-therapy for tumor ablation: from thermal coagulation to advanced irradiation techniques.

Image-guided tumor ablation has been established as a valuable adjunct in oncological treatment concepts. The majority of micro-therapeutic procedures is performed by applying thermal ablation, such as radiofrequency or laser. However, in view of the limitations of thermal ablation regarding tumor size or adjacent risk structures, novel techniques combining brachytherapy with modern interventional techniques have demonstrated favorable outcomes. In addition, advances in non-invasive percutaneous irradiation, such as extracranial stereotaxy, have demonstrated very competitive preliminary results. In this article, state-of-the-art techniques for micro-therapeutic tumor ablation are being described.

Brachytherapy↗

PubMed2006

CT-guided interstitial brachytherapy in the local treatment of extrahepatic, extrapulmonary secondary malignancies.

The purpose was to evaluate the safety and efficacy of high-dose-rate (HDR) CT-guided interstitial brachytherapy in the treatment of extrahepatic, extrapulmonary, secondary malignancies. Nineteen patients were included in this prospective study. The median age was 66 years (49-77). Underlying primaries comprised colorectal carcinomas in six, renal cell carcinoma in three, pancreatic carcinoma in three, cervical cancer in two, endometrial cancer in two and NSCLC, breast cancer and sarcoma in one patient each. All patients had undergone extensive pretreatments. CT-guided HDR brachytherapy employed a 192Iridium source. Dose planning for brachytherapy was performed using 3D CT data acquired after CT-guided percutaneous applicator positioning. MRI follow-up was performed 6 weeks and every 3 months post intervention. Primary endpoints were complications, local tumor control and progression-free survival. The median tumor diameter was 6 cm (2-15 cm). Tumor locations included the hepatoduodenal ligament, mesentery, adrenal gland, mesogastrium and local recurrences after rectal or pancreatic cancer. The minimal median dose in the target volume was 11 Gy (4-18 Gy). Minor complications comprised pain and fever (n=6, 32%). Major complications included one hospital death of unknown causes (n=1; 5%). Median follow-up was 7 months (1-16). Four patients (21%) died during the follow-up period. Local tumor control was 76.5% after 6 months and progression-free survival 47% after 6 months. Minimally invasive CT-guided HDR brachytherapy is safe and effective in the palliative treatment of extrahepatic, extrapulmonary secondary malignancies.

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PubMed2006

Local arterial infusion of superparamagnetic iron oxide particles in hepatocellular carcinoma: A feasibility and 3.0 T MRI study.

OBJECTIVES: We sought to prove feasibility of selective arterial infusion of superparamagnetic iron oxide (SPIO) particles in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: We studied 13 patients with HCC who underwent modified transarterial chemoembolization (TACE). Six patients received concurrent infusion of Ferucarbotran (Resovist, Schering, Berlin, Germany) in tumor-feeding arteries, and another 6 received MFL AS (MagForce, Nanotechnologies, Berlin, Germany). The iron content of both dispersions was 3.92 mg. One patient served as a control. All patients underwent magnetic resonance imaging (MRI) as baseline and immediate follow-up investigation. RESULTS: Selective arterial infusion of both SPIO particles resulted in significant intratumoral signal intensity decrease on T1-weighted sequences (P < 0.0001), which was greater after MagForce infusion compared with Resovist (P = 0.002). Only minimal amounts of dispersed particles were found in adjacent normal liver parenchyma. No change in intratumoral signal intensity was noted when ferromagnetic particles were omitted. CONCLUSIONS: Modified TACE with selective arterial infusion of SPIO particles can be used for precise tumor targeting in patients with HCC, for which MagForce appeared superior to Resovist.

Aged↗

PubMed2005

In vivo assessment of the tolerance dose of small liver volumes after single-fraction HDR irradiation.

PURPOSE: To prospectively assess a dose-response relationship for small volumes of liver parenchyma after single-fraction irradiation. METHODS AND MATERIALS: Twenty-five liver metastases were treated by computed tomography (CT)-guided interstitial brachytherapy. Magnetic resonance imaging was performed 1 day before and 3 days and 6, 12, and 24 weeks after therapy. MR sequences included T1-w gradient echo (GRE) enhanced by hepatocyte-targeted gadobenate dimeglumine. All MRI data sets were merged with 3D dosimetry data and evaluated by two radiologists. The reviewers indicated the border of hyperintensity on T2-w images (edema) or hypointensity on T1-w images (loss of hepatocyte function). Based on the total 3D data, a dose-volume histogram was calculated. We estimated the threshold dose for either edema or function loss as the D(90), i.e., the dose achieved in at least 90% of the pseudolesion volume. RESULTS: Between 3 days and 6 weeks, the extension of the edema increased significantly from the 12.9 Gy isosurface to 9.9 Gy (standard deviation [SD], 3.3 and 2.6). No significant change was detected between 6 and 12 weeks. After 24 weeks, the edematous tissue had shrunk significantly to 14.7 Gy (SD, 4.2). Three days postbrachytherapy, the D(90) for hepatocyte function loss reached the 14.9 Gy isosurface (SD, 3.9). At 6 weeks, the respective zone had increased significantly to 9.9 Gy (SD, 2.3). After 12 and 24 weeks, the dysfunction volume had decreased significantly to the 11.9 Gy and 15.2 Gy isosurface, respectively (SD, 3 and 4.1). CONCLUSIONS: The 95% interval from 7.6 to 12.2 Gy found as the minimal hepatocyte tolerance after 6 weeks accounts for the radiobiologic variations found in CT-guided brachytherapy, including heterogeneous dose rates by variable catheter arrays.

Adult↗

PubMed2005

Fusion imaging using a hybrid SPECT-CT camera improves port perfusion scintigraphy for control of hepatic arterial infusion of chemotherapy in colorectal cancer patients.

PURPOSE: Exclusive and homogeneous perfusion of the liver is considered essential for the efficacy of hepatic arterial infusion of chemotherapy (HAI). The aim of this study was to evaluate port perfusion scintigraphy in colorectal cancer patients using a hybrid SPECT-CT system for control of minimally invasive intra-arterial port systems within the scope of a phase II trial. METHODS: In 24 consecutive patients, the perfusion territories of intra-arterial hepatic port systems were assessed by port scintigraphy with( 99m)Tc-labelled macroaggregated albumin employing planar imaging, SPECT and SPECT-CT (acquired with a hybrid SPECT-CT camera). The results of blinded reading of the scintigraphic modalities concerning the intra- and extrahepatic perfusion pattern were compared with combined image analysis (angiography and contrast-enhanced dedicated CT) and patient history for validation. RESULTS: Extrahepatic perfusion was correctly seen in three patients, while suspected extrahepatic perfusion could be excluded in one. In 46 liver lobes, perfusion patterns were correctly visualised by SPECT-CT in 100% of cases (planar, 67%; SPECT, 86%). Assessing the perfusion pattern inside the liver on a segmental basis (segments, n=138), SPECT-CT revealed correct segmental assignment of tracer distribution in 100% and was significantly superior to SPECT alone (accuracy, 84%; p<0.001). The scintigraphic findings resulted in changes in therapeutic management in 8/24 patients (33%); in two of these the relevant findings were visualised only by SPECT-CT. CONCLUSION: In patients receiving HAI, port perfusion scintigraphy by fusion imaging with a hybrid SPECT-CT system provides important information for therapy optimisation and appears to be superior to SPECT alone.

Adult↗

PubMed2005

Imaging of single human carcinoma cells in vitro using a clinical whole-body magnetic resonance scanner at 3.0 T.

The purpose of the present study was to examine whether single human carcinoma cells labeled with iron oxide nanoparticles could be detected by magnetic resonance (MR) imaging on a clinical 3-T scanner using a surface coil only. WiDr human colon carcinoma cells were loaded with two kinds of iron oxide nanoparticles differing by coating and size: aminosilan-coated (MagForce) and carboxy-dextran-coated particles (Resovist). The latter were preferred by the colon carcinoma cell line used here and taken up much faster (12 h) than the smaller carboxydextran-coated Resovist (48 h). Labeled single carcinoma cells, distributed in an agarose gel in a monodisperse layer as controlled by light microscopy, became detectable as punctuate signal extinctions when using a small circularly polarized surface coil in conjunction with a T(2)*-weighted GE sequence at 3 T. The threshold for the detectability of labeled colon carcinoma cells ranged at a load of 4-5 mug iron/10(6) cells. Obviating the need for special hardware additions, this study opens a new lane for single-cell tracking on clinical 3-T MR scanners amenable to patient studies.

Aged↗

PubMed2005

Preoperative evaluation of living kidney donors using multirow detector computed tomography: comparison with digital subtraction angiography and intraoperative findings.

To assess the accuracy of multirow detector computed tomography (MDCT) for the evaluation of renal anatomy for preoperative donor assessment in living related kidney transplantation. MDCT-scans (4- and 16-slice-CT) of 51 consecutive living kidney donors (age, 51.6 +/- 9.7 years; range, 28-68 years) were analysed by three blinded observers and compared with digital subtraction angiography (DSA) and surgery. Contrast-enhanced MDCT was performed with 1 mm slice thickness reconstruction interval during arterial and venous phases. Supernumerary renal arteries, veins, early branching of vessels and abnormalities of the ureters were documented. The overall accuracy of computed tomography angiography (CTA) for detection and classification of surgically relevant arterial variants was 97% (99/102). The interpretation of 16-channel MDCT images was correct in all cases (accuracy, 100%), while the four-channel CTA had three incorrect results regarding the differentiation of early branching vessels from double renal arteries (accuracy, 93%). The overall accuracy of DSA was 91%. Renal vein abnormalities were correctly diagnosed with MDCT in 100% compared with 89% correct findings with DSA. There were three kidneys with incomplete ureter duplication, detected both with MDCT and DSA. MDCT demonstrated superior accuracy compared with non-selective DSA for the preoperative assessment of renal anatomy in living kidney donors; and for the distinction of supernumerary arteries versus early branching patterns, 16-channel CTA data were better than those of the four-channel system.

Adult↗

PubMed2005

CT-guided interstitial single-fraction brachytherapy of lung tumors: phase I results of a novel technique.

PURPOSES: To assess the safety of CT-guided brachytherapy of lung malignancies and to evaluate the initial therapeutic response. PATIENTS AND METHODS: Fifteen patients with 30 lung malignancies were included in this prospective phase I trial (metastases, 28; non-small cell lung cancers, 2). Pre-interventionally two patients had a vital capacity of < 80% (39% and 63%). These two patients, and one other, had FEV1 values of < 80% predicted (17%, 48%, and 64%). Tumors with a maximum diameter of 4 cm were treated with a single brachytherapy catheter that was positioned under CT-fluoroscopy. In two tumors with tumor diameters of 5.5 and 6.5 cm, two applicators were used. In one patient with an 11-cm irregularly shaped tumor, nine catheters were inserted. Treatment planning for 192Ir brachytherapy was performed using three-dimensional CT data that were acquired after percutaneous applicator positioning. All procedures were performed under local anesthesia. A follow-up CT was performed 6 weeks later and every 3 months pos-tintervention. RESULTS: The mean diameter of the 30 lung tumors was 2 cm (range, 0.6 to 11 cm; median diameter, 1.5 cm). The minimal dose within the tumor margin was 20 Gy in all 30 tumors treated. Except for nausea in one patient and focal hemorrhage detected on CT in two patients, no acute adverse events were recorded. One patient developed an abscess at the previous tumor location 9 months after treatment, which proved to be a local tumor recurrence. The median follow-up period was 5+ months with a local tumor control of 97%. CONCLUSION: The novel technique of CT-guided interstitial brachytherapy was safe for the treatment of lung tumors and yielded a very low complication rate. The initial data on therapeutic response are promising.

Adult↗

PubMed2004

CT-guided interstitial brachytherapy of liver malignancies alone or in combination with thermal ablation: phase I-II results of a novel technique.

PURPOSE: To assess the safety and efficacy of CT-guided brachytherapy alone or in combination with laser-induced thermotherapy (LITT) in patients with liver malignancies. METHODS AND MATERIALS: Thirty-seven patients presented with 36 liver metastases and two primary liver carcinomas. Twenty-one patients were treated with CT-guided high-dose-rate brachytherapy alone using a 192Ir source. Sixteen patients received brachytherapy directly after MRI-guided LITT. The indications for brachytherapy alone were a tumor size >5 cm, adjacent central bile duct or adjacent major vessels causing unfavorable cooling effects for thermal ablation, and technical failures of LITT. The dosimetry for brachytherapy was performed using three-dimensional CT data acquired after percutaneous applicator positioning. On average, a minimal dose of 17 Gy inside the tumor margin was applied (range, 10-20 Gy). RESULTS: The mean tumor size was 4.6 cm (range, 2.5-11 cm). The mean liver volume receiving > or =5 Gy was 16% (range, 2-40%) of the total liver. Severe complications were recorded in 2 patients (5%). One patient developed acute liver failure possibly related to accidental continuation of oral capecitabine treatment. Another patient demonstrated obstructive jaundice owing to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. A commonly encountered moderate increase of liver enzymes was greatest in patients with combined treatment. The local control rate after 6 months was 73% and 87% for combined treatment and brachytherapy alone, respectively. CONCLUSION: CT-guided brachytherapy using three-dimensional CT data for dosimetry is safe and effective alone or in combination with LITT. Brachytherapy as a stand-alone treatment displayed genuine advantages over thermal tumor ablation.

Adult↗

PubMed2004

[CT-Guided brachytherapy. A novel percutaneous technique for interstitial ablation of liver metastases].

PURPOSE: To assess safety and efficacy of CT-guided brachytherapy of liver malignancies. PATIENTS AND METHODS: 21 patients with 21 liver malignancies (19 metastases, two primary liver tumors) were treated with interstitial CT-guided brachytherapy applying a (192)Ir source. In all patients, the use of image-guided thermal tumor ablation such as by radiofrequency or laser-induced thermotherapy (LITT) was impeded either by tumor size > or = 5 cm in seven, adjacent portal or hepatic vein in ten, or adjacent bile duct bifurcation in four patients. Dosimetry was performed using three-dimensional CT data sets acquired after CT-guided positioning of the brachytherapy catheters. RESULTS: The mean tumor diameter was 4.6 cm (2.5-11 cm). The mean minimal tumor dose inside the tumor margin amounted to 17 Gy (12-20 Gy). The proportion of the liver parenchyma exposed to > 5 Gy was 18% (5-39%) of total liver parenchyma minus tumor volume. Nausea and vomiting were observed in six patients after brachytherapy (28%). One patient demonstrated obstructive jaundice due to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. We commonly encountered asymptomatic increases of liver enzymes. Local control rates after 6 and 12 months were 87% and 70%, respectively. CONCLUSION: CT-guided brachytherapy is safe and effective. This technique displays broader indications compared to image-guided thermal ablation by radiofrequency or LITT with respect to tumor size or localization.

Aged↗

PubMed2004

A randomized trial assessing the value of ultrasound-guided puncture of the femoral artery for interventional investigations.

Using a prospectively collected database of patients undergoing diagnostic or therapeutic angiography via transfemoral access, we sought to determine those patients who may benefit from ultrasound-guided puncture of the femoral artery. One-hundred-twelve patients with normal anticoagulation parameters were randomized in two groups. Fifty-six patients received ultrasound-guided puncture of the femoral artery, 56 patients underwent traditional palpation-guided vessel cannulation. Parameters assessed included procedure-time, number of attempts for successful puncture, intensity of the arterial pulse, previous ipsilateral punctures, history and risk factors of arteriosclerosis and leg circumference at the site of puncture. The data was analyzed by using outcome measures according to evidence-based medicine criteria. Only in patients with weak arterial pulse and thoses with a leg circumference of 60 cm or greater ultrasound guidance significantly decreased the number of attempts needed as well as the time for successful arterial puncture. In both patient subgroups, the number needed to treat (NNT) was 2, the absolute benefit increase (ABI) was 50 and 57%, respectively. In contrast, time for vessel cannulation was increased in patients with strong arterial pulse using ultrasound guidance. No significant differences were found with respect to diminished complications neither comparing both patient groups nor comparing risk subgroups. In conclusion ultrasound guidance for femoral artery access is recommended only in patients with a weak or absent arterial pulse and obese patients.

Databases as Topic↗

PubMed2004

Hepatic arterial port systems for treatment of liver metastases: factors affecting patency and adverse events.

PURPOSE: To assess the outcome of interventional hepatic arterial port placement in a prospective phase II trial. MATERIALS AND METHODS: One-hundred five consecutive patients were included in this study. Primary endpoint was port patency; secondary endpoints were complications, toxicity, response, and progression free and overall survival. Seventy-eight patients presented with liver metastasis only, 6 patients had additional minor extrahepatic disease, and 21 patients had no evidence of disease after liver resection, laser-induced thermotherapy, or computed tomography (CT)-guided interstitial brachytherapy of liver metastasis. Exclusive access route was the femoral artery. Subgroup analysis compared either 4-F catheters (n = 58) to 2.2-F (n = 33) and 2.7-F (n = 20) microcatheters or different strategies in anatomic variants of the celiac branch: neglect (n = 10) or embolization of minor hepatic feeders (n = 11), splenic arterial port (n = 8), double port (n = 7). RESULTS: Technical success was 99%. Assisted port patency after 6 months was 93%. Complications demanding port revisions were significantly lower in patients receiving 4-F versus 2.2-F and 2.7-F systems (P <.001), with disconnection as the major problem with use of microcatheters. Hepatic artery thrombosis occurred in 10 patients (9%), with successful lysis in two patients. With use of 4-F and 2.2-F catheters, there was no difference with respect to catheter occlusion or hepatic thrombosis. No differences were noted in complications or outcome applying four different strategies in celiac branch variants. In a subgroup of patients receiving folinic acid/5-fluorouracil (170 mg/600 mg; 10% dose escalation per cycle) for 5 days every 4 weeks only 15% experienced Grade 3 toxicity. Patients with liver metastasis and salvage therapy demonstrated progression-free survival of 63% after 6 months and a median survival of 16 months. CONCLUSION: Interventional placement of hepatic arterial port systems may overcome frequent hepatic arterial chemotherapy failures as encountered in all published major trials on hepatic arterial infusion.

Adult↗

PubMed2004

Liver malignancies: CT-guided interstitial brachytherapy in patients with unfavorable lesions for thermal ablation.

PURPOSE: To evaluate computed tomography (CT)-guided brachytherapy in patients with very large liver malignancies or with liver tumors located adjacent to the liver hilum. MATERIALS AND METHODS: In this prospective nonrandomized phase II trial, we treated 20 patients (19 liver metastases and one cholangiocarcinoma) with CT-guided high-dose-rate (HDR) brachytherapy using a (192) Iridium source. All patients demonstrated no functional liver degradation prior to irradiation. Entry criteria were liver tumors > 5 cm (group A, n = 11, no upper limit) or liver tumors < or = 5 cm adjacent to the liver hilum (group B, n = 9). Dose planning for brachytherapy was performed with three dimensional (3D) CT data acquired after percutaneous applicator positioning. Magnetic resonance (MR) imaging follow-up was performed 6 weeks and every 3 months post intervention. Primary endpoints were complications, local tumor control (absence of tumor growth after treatment followed by shrinkage of the lesion starting at 6 months) and progression-free survival. RESULTS: The mean tumor diameter was 7.7 cm (range, 5.5-10.8 cm) in group A, 3.6 cm (range, 2.2-4.9 cm) in group B. On average, a minimal dose of 17 Gy in the target volume was applied (range, 12-25 Gy). Severe side effects were recorded in two patients (10%). One patient demonstrated an obstructive jaundice caused by tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. One patient developed intra-abdominal hemorrhage that was treated by a single blood transfusion and has ceased. We frequently encountered moderate increases of liver enzymes (70% of patients) and bilirubin (50% of patients) without clinical symptoms and thus considered to be insignificant. The median follow-up was 13 months. In group A (tumors > 5 cm), primary local tumor control after 6 and 12 months was 74% and 40%, respectively; in group B, it was 100% and 71%, respectively. All but one local recurrence (in a patient with diffuse tumor progression) were successfully treated during another CT-guided brachytherapy leading to a primary assisted local control of 93% after 12 months. CONCLUSION: CT-guided brachytherapy based on individual dose plans and 3D CT data sets generated encouraging results in large liver malignancies as well as in tumors located adjacent to the liver hilum.

Adult↗

PubMed2004

Description and characterization of the novel hyperthermia- and thermoablation-system MFH 300F for clinical magnetic fluid hyperthermia.

Magnetic fluid hyperthermia (MFH) is a new approach to deposit heat power in deep tissues by overcoming limitations of conventional heat treatments. After infiltration of the target tissue with nanosized magnetic particles, the power of an alternating magnetic field is transformed into heat. The combination of the 100 kHz magnetic field applicator MFH 300F and the magnetofluid (MF), which both are designed for medical use, is investigated with respect to its dosage recommendations and clinical applicability. We found a magnetic field strength of up to 18 kA/m in a cylindrical treatment area of 20 cm diameter and aperture height up to 300 mm. The specific absorption rate (SAR) can be controlled directly by the magnetic field strength during the treatment. The relationship between magnetic field strength and the iron normalized SAR (SAR(Fe)) is only slightly depending on the concentration of the MF and can be used for planning the target SAR. The achievable energy absorption rates of the MF distributed in the tissue is sufficient for either hyperthermia or thermoablation. The fluid has a visible contrast in therapeutic concentrations on a CT scanner and can be detected down to 0.01 g/l Fe in the MRI. The system has proved its capability and practicability for heat treatment in deep regions of the human body.

Biophysical Phenomena↗

PubMed2003

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography.

The aim of this study was to compare the sensitivity and specificity of digital chest radiography alone with digital chest radiography combined with dual-energy chest radiography in the detection of small non-calcified pulmonary nodules. Standard and dual-energy radiographs were obtained with a flat-panel digital chest system. Four radiologists reviewed digital posteroanterior chest radiographs in random order either alone or in conjunction with dual-energy soft tissue and bone images. Twenty patients with a total of 59 pulmonary nodules (median 0.5 cm, range 0.3-2.5 cm) confirmed by computed tomography (HU < or =100) were included. A level of confidence for each diagnosis was documented using a rating scale of 1-5. Brunner and Langer's test was performed for statistical analysis. Subgroup analysis was performed for nodules greater than 1 cm, 1-0.5 cm, and <0.5 cm. For posteroanterior chest radiography, sensitivity was 33%, positive predictive value 83%, specificity 81%, and negative predictive value 30%. Review in conjunction with dual-energy images resulted in a sensitivity of 42%, positive predictive value 88%, specificity 85%, and negative predictive value 34%. The increase of nodule detection overall as well as for different size categories was significant (p<0.05). The increase of the confidence level rating was also significant (p<0.001). Dual energy added to standard posteroanterior chest radiography significantly improves the sensitivity, specificity, and confidence in detection of small non-calcified pulmonary nodules.

Humans↗

PubMed2003

Portable computed tomography performed on the intensive care unit.

OBJECTIVE: We report on the use of portable computed tomography (CT) in an ICU setting. The additional diagnostic gain and therapeutic consequences were assessed. PATIENTS: Ten ICU patients underwent 14 portable chest CT examinations. In 64% maximum intensive care was required, according to TISS28 (>40), and 42% were at a risk of mortality higher than 25% (MODS) on the day of portable CT examination. In three portable CT examinations the patients were considered not transportable and were examined directly in the patient room. All other examinations were performed in a special interventional suite directly on the ICU. RESULTS: Of 14 examinations 8 (57%) resulted in a change in patient management within 48 h. All patients profited from portable CT and no hazards occurred related to CT. CONCLUSIONS: To perform portable CT in the interventional suite on the ICU allows immediate minimally invasive therapeutic interventions and provides full ICU monitoring.

Adult↗