Biomedical subjects

R Hammerstingl

Publications and source records attributed to R Hammerstingl.

25 records · Page 2Linked to original sources

PubMed1995

Malignant liver tumors treated with MR imaging-guided laser-induced thermotherapy: technique and prospective results.

PURPOSE: To evaluate magnetic resonance (MR) imaging-guided laser-induced thermotherapy (LITT) of liver metastases. MATERIALS AND METHODS: In a phase II study, 20 patients with 33 metastases from colorectal carcinoma (75%) or other primary tumors (25%) underwent LITT. MR thermometry performed with fast low-angle shot sequences was used to monitor therapy on-line, and dynamic and static contrast material-enhanced MR images enabled estimation of the degree of resultant necrosis. Follow-up studies were performed 3 months after thermotherapy. RESULTS: The thermosequences enabled accurate on-line monitoring in 85% of lesions. In 69% of lesions 20 mm in diameter or smaller, contrast-enhanced MR images depicted substantial necrosis, with a local tumor control rate of 69% after 6 months and 44% after 12 months. Among lesions larger than 20 mm, necrosis was frequently incomplete, with a local control rate of only 41% after 6 months and 27% after 12 months. CONCLUSION: MR imaging-guided LITT of liver metastases is a safe and promising therapy for liver metastases.

Adult↗

PubMed1995

[Laser-induced thermotherapy of liver metastases with MRI control. Prospective results of an optimized therapy procedure].

In a prospective study MR-guided laser-induced thermotherapy (LITT) of liver metastases was optimized and the clinical parameters evaluated. Seventeen patients (4 women, 13 men) with a total of 29 lesions underwent LITT in 25 sessions through 1 March 1994. Twelve of them suffered from colorectal carcinomas, 5 from other primary tumors. Under local anesthesia a maximum of 5 lesions per patient were treated. For MR-guided LITT a neodymium yttrium aluminum garnet laser (Nd-YAG 1064 nm) with energy varying from 3 to 7.5 W was used. Energy and application time were defined through a computer program; they varied, dependent on the lesion size, location and consistency. To monitor the progress of LITT two special thermosensitive MR sequences (Thermo-Turbo-FLASH and FLASH-2D sequences) were individually optimized, whereby the increase in temperature correlates with an increase in signal loss. All procedures were well tolerated without significant early or late side effects. In only one patient was minimal air documentated in the pleural cavity with spontaneous resorption. Patients were dismissed without complaints after 24-h hospitalization. The control parameters of the contrast-enhanced dynamic MRI documented at optimal response a hypointense signal around the tip of the laser applicator, in accordance with laser-induced necrosis. In lesions 20 mm or smaller, nearly 100% tumor necrosis was achieved and in lesions larger than 20 mm, only 50%. Follow-up evaluation 6 months after treatment shows a significantly better response in lesions with a diameter of 20 mm or smaller, with a local tumor control rate of 66%. In lesions larger than 20 mm only a local tumor control rate of 35% could be achieved. Laser-induced thermotherapy (LITT) represents a new, minimally invasive technique for tumor destruction and a high response rate in small liver metastases.

Adult↗

PubMed1995

[Differential diagnosis of focal liver lesions with MRI using the superparamagnetic contrast medium endorem].

PURPOSE: In a phase III/III-B trial the specific contrast enhancement of benign liver tumors, especially FNH and adenoma, versus malignant liver tumors such as HCC and metastases (colorectal and endocrine tumors) was evaluated using the superparamagnetic iron oxide ENDOREM. MATERIAL AND METHODS: 57 patients were prospectively investigated using T2-(TR/TE=2000/90) and T1-(550/15) weighted spinecho (SE), FLASH-2D-gradientecho (GE), and fat suppressed (FATSAT) sequences before and after administration of ENDOREM (concentration: 0.2 mmol Fe/ml, dose: 15 micromol/kg (b.w.) in transverse slice orientation on a 1.5 Tesla MAGNETOM (Siemens, 63 SP). In 8 patients an in vivo-in vitro correlation 30 minutes after resection was performed. In 12 patients benign primary liver tumors (FNH (n = 10), adenoma (n = 1), and hemangioma (n = 1) were histopathologically proved. Malignant liver tumors (HCC (n = 11, cholangiocarcinoma (n = 1), metastases from colorectal carcinoma (n = 13), and endocrine tumors (n = 4)) were found in 29 patients. 11 patients with liver cirrhosis due to Wilson's disease and 5 with cirrhosis due to other reasons were investigated. RESULTS: Contrast-enhanced studies allowed detection of more lesions in 19 of 41 patients with liver tumors. Benign liver tumors showed significant loss of signal intensity of 43.0% +/- 17.9 for FNH, 32.4% for adenoma and 10.2% for hemangioma in proton density-weighted SE images. Malignant tumors showed only minimal signal loss: HCC: 5.3% +/- 17, cholangiocarcinoma: -1.6%, colorectal: -2.0% +/- 11.1, endocrine metastases: 4.2% +/-4.1. Normal liver parenchyma and spleen tissue demonstrated significant signal loss of 59.2% +/- 14.9 and 42.3 +/- 012.5. In ten patients and 13 lesions of FNH, a capsule was seen in 7.7% plain and 23.1% enhanced. Scar tissue was found in 30.8% plain, 84.6% enhanced. In the patient with adenoma, capsule with contrast enhancement was seen, but no scar was detected, whereas in patients with HCC a capsule was seen in three cases enhanced. Statistical analysis (Friedman-test, Wilcoxon-test) showed a statistically significant difference in signal loss between benign and malignant liver lesions (p < 0.05). CONCLUSION: The use of superparamagnetic iron oxide ENDOREM) allows differentiation of benign and malignant liver tumors on the basis of contrast enhancement, existence and specific enhancement of capsule or scar. In vitro correlation show some limitations of in vivo MRI.

Adenoma, Liver Cell↗

PubMed1994

[MRT of the liver in Wilson's disease].

To show that Wilson's disease is one likely cause of multiple low-intensity nodules of the liver we obtained MR images in 16 patients with clinically and histopathologically confirmed Wilson's disease. Corresponding to morphological changes MRI enabled the subdivision of the patients into two groups. Using a T2-weighted spin-echo sequence (TR/TE = 2000/45-90) liver parenchyma showed multiple tiny low-intensity-nodules surrounded by high-intensity septa in 10 out of 16 patients. 5 patients had also low-intensity nodules in T1-weighted images (TR/TE = 600/20). In patients of this group histopathology revealed liver cirrhosis (n = 7) and fibrosis (n = 2). Common feature of this patient group was marked inflammatory cell infiltration into fibrous septa, increase of copper concentration in liver parenchyma and distinct pathological changes of laboratory data. In the remaining 6 patients no pathological change of liver morphology was demonstrated by MRI corresponding to slight histopathological changes of parenchyma and normal laboratory data. As low-intensity nodules surrounded by high intensity septa can be demonstrated in patients with marked inflammatory infiltration of liver parenchyma MRI may help to define Wilson patients with poorer prognosis. In patients with low-intensity nodules of the liver and unknown cause of liver cirrhosis laboratory data and histopathology should be checked when searching for disorders of copper metabolism.

Adolescent↗

PubMed1994

[The value of the liver-specific superparamagnetic contrast medium AMI-25 for the detection and differential diagnosis of primary liver tumors versus metastases].

The value of the superparamagnetic contrast medium AMI-25 and its clinical acceptability was investigated in a phase-III-multicenter study. 18 patients with primary and secondary hepatic tumours were studied using T2- and T1-weighted spin-echo sequences, FATSAT sequences and FLASH-2-D-breathold sequences, both before and after intravenous application of AMI-25 (0.2 mmol GE/ml 15 mmol/kg KG in 100 ml 5% glucose infusion), using a 1.5 Tesla MRT (Magnetom 63 SP, Siemens). In 6 patients the MRT findings could be correlated with in vitro results within 30 minutes following surgical resection. In 8 patients a diagnosis of metastases was made. Amongst patients with primary liver tumours (FNH 6 cases, HCC 3 cases, adenomatosis 1 case) 3 of the 10 patients showed more lesions following the injection of contrast; similarly, in 4 patients of the 8 with secondary tumours contrast increased the number of visible lesions. The absence of contrast enhancement separated primary from secondary lesions. Amongst the patients with secondary liver tumours, in vitro correlation always showed more tumours than had been visualised whereas there was exact in vivo/in vitro correlation amongst patients with primary liver tumours.

Contrast Media↗

PubMed1992

[Magnetic resonance tomography and magnetic resonance angiography in lymphangiomatosis].

Generalised lymphangiomatosis is a rare benign congenital abnormality of the lymphatic vessels with a complex pattern. 3 patients with different types of lymphangiomatosis were studied by MRT and MRA and histopathologically. All patients had multiple organ involvement in the abdomen, the skeleton and the skull. The basis in each case was lymphangiomatosis of capillary-cavernous, cystic or cavernous type. The results of MRT and MRA in diagnosing splenic, vascular and skeletal changes correlated accurately with operative findings and with the histopathological classification. In summary, MRT combined with MRA and using paramagnetic contrast media are the diagnostic methods of choice for the investigation of generalised lymphangiomatosis with multiple organ involvement.

Abdomen↗

PubMed1992

[Magnetic resonance tomography of the hepatobiliary system: indications, limitations and outlook].

In a prospective study we examined the diagnostic value of MRI and MR cholangiography (MRC) in patients suffering from hepatobiliary disease. By using hepatobiliary contrast media (Mn-DPDP, Gd-BOPTA), sensitivity and specificity of MRI were significantly increased. In 65 patients we comparatively analyzed the diagnostic results of MRI and MRC versus ultrasound, CT and invasive techniques such as ERCP. We conclude that the use of MRI and MRC improves the diagnostic evaluation of patients with hepatobiliary disease.

Biliary Tract Diseases↗