Biomedical subjects

M G Mack

Publications and source records attributed to M G Mack.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Transarterial chemoembolization (TACE) of liver metastases. A palliative therapeutic approach].

Metastatic involvement of the liver determines the treatment. Hepatic artery chemoembolization (TACE) represents a safe palliative treatment for patients with unresectable liver metastases. Technical treatment, indication and results of the TACE are reported. The results of TACE depend on primary cancer, size and vascularisation of the hepatic tumors. Our results with out patient treatment of 245 patients prove that TACE results in a extremely low rate of side effects. Combination of TACE with local ablative treatment may present potentially curative treatment option for unresectable tumors.

Adult↗

PubMed2001

[Transarterial chemoembolization in hepatocellular carcinomas: technique, indications, results].

BACKGROUND: At time of diagnosis 80% of the patients with hepatocellular carcinoma (HCC) could not be treated with surgical treatments, so that transarterial chemoembolization (TACE) was used as an neoadjuvant or palliative treatment modality. MATERIAL AND METHODS: 60 patients were treated with 217 TACE courses, in the mean 3.6 TACE treatments per patient with an 4 week interval. TACE was performed with a dispersion of lipiodol, mitomycin C and spherex. 11 patients (18.3%) were treated in a neoadjuvant protocol with successful ablation. Lipiodol retention and size of the tumors were evaluated by CT and MRI. RESULTS: 60 patients were successful treated with TACE. After treatment a primary high lipiodol retention was displayed and in 68 (63.3%) patients a reduction of the tumor size and in 11 (20%) patients a reduction of tumor growth rate was noted. The 1 year survival rate was 59%. After response to TACE and reducing the tumor size 11 patients could be treated with MR-guided LITT 4 to 6 weeks post embolization. CONCLUSION: Chemoembolization is a minimal invasive and outpatient treatment protocol for HCC. TACE might be indicated as a palliative treatment to control the diseased liver. If repeated TACE alters the size and structure of primary unresectable HCC TACE expands the indication for MR-guided LITT.

Adult↗

PubMed2001

[Oligonodular hepatocellular carcinoma (HCC): MR-controlled laser-induced thermotherapy].

PURPOSE: To prospectively evaluate the therapeutic potential of MR-guided laser-induced thermotherapy (LITT) in patients with oligonodular hepatocellular carcinoma. MATERIAL AND METHODS: 39 patients with 61 intrahepatic lesions were treated with LITT. The Nd:YAG laser fiber was introduced with a percutaneously positioned irrigated laser application system. Qualitative and quantitative MR parameters and clinical data were evaluated. RESULTS: All patients tolerated the procedure well under local anesthesia. All observed complications were minor and no further treatment was necessary. Online MR thermometry allowed exact visualization. Lesions up to 2 cm in diameter could be efficiently treated with a single laser application, larger lesions were treated simultaneous multiapplication. In 97.5% we achieved a complete necrosis of the tumor and a 5 mm safety margin, resulting in a complete destruction of the tumor without local recurrences. Mean survival was 4.4 years (95% CI: 3.6-5.2 years) after the time of diagnoses of the HCC (Kaplan-Meier-method). CONCLUSION: In intrahepatic oligonodular involvement of hepatocellular carcinoma LITT appears to be an effective therapeutic procedure with a high tumor control rate and better survival data.

Adult↗

PubMed2001

[Needle holder for reducing radiation burden of examiners in CT-assisted puncture. Technical contribution].

PURPOSE: To evaluate the use of a needle guide for CT guided puncture for the reduction of radiation dose of the interventional radiologist. MATERIAL AND METHODS: A total of 20 CT-guided punctures was performed. An approach from anterior was used in 12 cases and an approach from lateral was used in 8 cases. We evaluated the practicability, the precision and possible artifacts caused by the needle guide. RESULTS: All 20 punctures could be performed with the needle guide without any complications. We observed no artifacts on the images due to the needle guide. The ability to guide the puncturing needle was not affected by the needle guide. The use and the efficacy of the needle guide were best for the approach from anterior as well as a lateral approach. However, for angulated appraches from caudal to cranial there was no benifit regarding the distance of the hands of the interventional radiologist from the radiation beam of the CT unit. CONCLUSIONS: The use of the needle guide is reducing the radiation dose of the interventional radiologist during CT-guided punctures.

Biopsy, Needle↗

PubMed2001

MR-guided laser-induced thermotherapy in recurrent extrahepatic abdominal tumors.

The aim of this study was to evaluate the feasibility of MR-guided laser-induced thermotherapy (LITT) for treatment of recurrent extrahepatic abdominal tumors. In 11 patients (6 women and 5 men; mean age 53 years, age range 29-67 years) with 14 lesions the following tumors were treated in this study: paravertebral recurrence of hypernephroma (n=1); recurrence of uterus carcinoma (n=1); recurrence of chondrosarcoma of the pubic bone (n=1); presacral recurrence of rectal carcinoma (n=1); recurrent anal cancer (n=1); metastases in the abdominal wall (n=1); and lymph node metastases from colorectal cancer (n=8). A total of 27 laser applications were performed. A fast low-angle shot 2D sequence (TR/TE/flip angle=102 ms/8 ms/70 degrees ) was used for nearly real-time monitoring during treatment. All patients had no other treatment option. Seventeen LITT sessions were performed using a conventional laser system with a mean laser power of 5.2 W (range 4.5-5.7 W), and 10 LITT session were performed using a power laser system with a mean laser power of 28.0 W. In 10 lesions total destruction could be achieved. In the remaining recurrent tumors, significant reduction of tumor volume by 60-80% was obtained. All patients tolerated the procedure well under local anesthesia. No complications occurred during treatment. Laser-induced thermotherapy is a practicable, minimally invasive, well-tolerated technique that can produce large areas of necrosis within recurrent tumors, substantially reducing active tumor volume if not resulting in outright destruction of tumor.

Abdominal Neoplasms↗

PubMed2001

Laser-induced thermotherapy of malignant liver tumors: general principals, equipment(s), procedure(s)--side effects, complications and results.

PURPOSE: To prospectively evaluate the therapeutic potential of MR-guided and ultrasound-guided laser-induced thermotherapy (LITT) in patients with liver metastases and oligonodular hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Between June 1993 and June 2000 a total of 1608 LITT sessions was performed to treat 1914 lesions in 676 consecutive patients. The Nd-YAG laser fiber was introduced with a percutaneously positioned cooled application set. Qualitative and quantitative ultrasound and magnetic resonance (MR) parameters, as well as clinical data were evaluated. RESULTS: All patients tolerated the procedure well under local anesthesia; no relevant clinical complications were observed. The mean laser power was 25 W and the mean duration was 25 min. MR proved to be superior over computed tomography and ultrasound due the thermosensitivity of the MR sequences allowing a better visualization of the volume of laser-induced changes and their relation to the neighboring geographical structures. The ultrasound-guided LITT should be restricted for patients with contraindications for MR imaging monitoring and for selected patients with low diameter oligonodular HCC. In 95% of cases, we achieved a complete necrosis of the tumor and a 5-mm safety margin, resulting in a complete destruction of the tumor without local recurrences. Mean survival in this group was 35 months (calculated with the Kaplan-Meier method). CONCLUSION: MR-guided, or ultrasound-guided, LITT appears to be a safe and effective treatment protocol for liver metastases and oligonodular HCC.

Carcinoma, Hepatocellular↗

PubMed2001

[Modern alternatives to resection of metastases--MR-guided laser-induced thermotherapy (LITT) and other local ablative techniques].

In patients with liver metastases of different primaries modern local ablative techniques such as laser-induced thermotherapy (LITT) and radiofrequency ablation (RF) are minimal invasive therapy options, if the patients were no candidates for liver surgery. A maximum of 5 cm lesion diameter and not more than 5 metastases without extrahepatic are treatable. MR-guided LITT is currently performed by means of implantable percutaneous catheter systems in local anesthesia and with outpatient management. RF is performed sometimes in general anesthesia and a hospital admission for some days. Liquid irrigated application systems are available both for LITT and for radiofrequency therapy and realized necrosis diameter up to 6 cm. At present LITT enables a local tumor control better than 98% for localized liver metastases without extrahepatic spreading patterns. In a group of 846 patients the average survival times were 4.0 years for patients with liver metastasis from different primary tumors. The data for RF ablation confirm the high value for tumor control for hepatocellular carcinomas with poorer results for liver metastases. Percutaneous MR-guided LITT permits good tumor control of liver metastases smaller than 5 cm and less than 5 in number with an improvement of survival times.

Carcinoma, Hepatocellular↗

PubMed2001

[Percutaneous laser ablation of malignant liver tumors].

PURPOSE: To present the technical data, methods and results of percutaneous laser ablation of malignant tumors. PATIENTS AND METHODS: In the period from June 1993 to April 2000 a collective of 600 patients with malignant liver tumors and liver metastases from different primary tumors were treated via MR-guided LITT. After sonographically or CT-guided puncture MR-compatible laser catheters were positioned. The tumor destruction was visualized via MR-thermometry. The checkup and the therapy accomplishment ensued in the course of an ambulant therapy concept. RESULTS: In the course of a local accomplished LITT of liver metastases and malignant liver tumors a local tumor control rate of 97.8 % was achieved. The complication rate was extremely low with a value of 2.2 % (1 441 treatments). The lethality rate was 0.1 %. The mean survival time referring to the whole patient collective was 47.7 months, in the case of liver metastases from a colorectal cancer a value of 46.8 months was achieved. CONCLUSION: MR-guided LITT is a local effective therapy with low morbidity in malignant liver tumors with a maximum quantity of 5 and a size of </= 5 cm.

Adult↗

PubMed2001

[Renal enhancement and excretion of the hepatobiliary contrast agent Gd-EOB-DTPA].

PURPOSE: To evaluate the clinical value of the renal clearance using MR imaging with different doses of gadolinium ethoxybenzyl-DTPA (Gd-EOB-DTPA) in comparison to gadolinium DTPA (Gd-DTPA). MATERIAL AND METHODS: In a double-blind and randomized clinical phase II study. MR imaging at 1.5 T was performed in 61 patients with five different doses of Gd-EOB-DTPA (3, 6, 12.5, 25 and 50 micromol/kg b. w. as a bolus injection). The study protocol comprised T(1)- and T(2)-weighted spin-echo magnetic resonance and two-dimensional fast low-angle shot imaging before and at increasing intervals for up to 45 min after injection of Gd-EOB-DTPA. These images were compared with Gd-DTPA-enhanced imaging (0.1 mmol/kg b. w. as a bolus injection). RESULTS: After bolus injection of the hepatobiliary MR contrast agent Gd-EOB-DTPA a renal elimination was observed. Immediately after the injection of Gd-EOB-DTPA until the eighth minute a corticomedullary enhancement of the kidney was conspicuous. After the fourth minute a contrast enhancement could be seen in the renal pelvis. The best enhancement was noted after 20 minutes in the FLASH GRE and T(1)-weighted images with good pelvicaliceal contrast. After 45 minutes an outflow of Gd-EOB-DTPA into the ureter could be observed. CONCLUSION: In addition to the hepatobiliary secretion Gd-EOB-DTPA appears useful for the evaluation of renal structures and renal function on account of the renal excretion without diuretic preparation of the patients.

Adult↗

PubMed2001

Effects of time and movements of the preshot routine on free throw shooting.

This study examined the effects of length and movements of preshot routines on free throw shooting in basketball. 17 members of an intercollegiate men's basketball team attempted 20 free throws in each of four different conditions: (1) normal routine and time, (2) normal routine with altered time, (3) altered routine with normal time, and (4) altered routine with altered time. Free throw performance was measured using an objective 5-point scoring system. A multivariate analysis of variance indicated a significant effect for routine. Neither time nor routine by time was significant. Results indicated that altering the movements in the routine had a significant effect on performance while lengthening the time did not.

Adolescent↗

PubMed2000

[Chronic infections of the paranasal sinuses].

PURPOSE: Evaluation of the clinical value of imaging techniques for chronic inflammatory disease of paranasal sinuses. MATERIALS AND METHODS: Beside clinical tests imaging of the paranasal sinuses is based on the techniques like conventional X-ray studies, ultrasound, computed tomography and magnetic resonance techniques. RESULTS: The value of conventional X-ray is lowered and is today focused on the diagnosis of acute sinusitis with fluid level and the detection of inflammatory foci. Spiral-CT using transverse and coronal orientation or reformatted images is considered as the diagnostic method of choice for the majority of clinical questions. MRT allows additional diagnostic informations in completely obstructed maxillary sinuses and patients with suspected anterior skull base involvement. CONCLUSION: Imaging techniques do provide substantial diagnostic informations in patients with chronic sinusitis.

Chronic Disease↗

PubMed2000

[Inflammatory diseases of the pharynx. The imaging findings and diagnostic strategy].

PURPOSE: To demonstrate imaging findings in inflammatory diseases of the pharynx and possible complications. MATERIAL AND METHODS: Radiologic imaging of the pharynx is based on the use of conventional X-ray films, computed tomography and magnetic resonance imaging, plain and contrast enhanced. RESULTS: The advantages of cross sectional imaging techniques like CT and MRT lie in the possibility to diagnose submucosal disease and localized as well as general complications. Most frequently abscesses and phlegmonous diseases have to be diagnosed. CT proves advantageous due to its fast imaging protocol and the widely availability. MRI is superior due to its superior soft tissue contrast and the multiplanar imaging. CONCLUSION: Spiral-CT and MRI mean valuable diagnostic tools for the evaluation of inflammatory diseases of the pharynx and possible complications.

Adult↗

PubMed2000

[CT-guided percutaneous intratumoral chemotherapy with a novel cisplatin/epinephrine injectable gel for the treatment of inoperable malignant liver tumors].

PURPOSE: To evaluate prospectively the volumetric changes of tumor and necrosis in unresectable malignant liver tumors and the clinical aspects after CT-guided direct intratumoral administration of a novel cisplatin/epinephrine injectable gel in a clinical phase II study. PATIENTS AND METHODS: 8 patients with 17 colorectal liver metastases with a mean volume of 42 ml were treated with a mean of 5.1 injections and 8 patients with 11 HCC nodules (mean volume of 22.1 ml) with a mean of 3.25 treatments with CT-guided local administration of a novel cisplatin/epinephrine gel. This method of administration provides a higher local and lower systemic drug concentration. Volumes of tumor and necrosis prior to and after treatment were measured by computer-generated volumetric analysis. RESULTS: Contrast-enhanced studies verified pretherapeutic tumor necrosis with a value of 12.6% in the metastases and 0.6% in the HCC nodules. Intratumoral drug administration resulted in a necrotic volume of 110% in metastases and 128% in HCC versus the mean initial tumor volume, at least 4 treatments resulted in 122% necrosis in metastases and 130% in HCC. Local therapy control rate for the follow-up to 6 months was 38% and 83.3% for the group of metastases and HCC, respectively. CONCLUSIONS: Direct intratumoral injection of a novel cisplatin/epinephrine injectable gel results in an induction of a relevant necrosis in malignant liver tumors, with a substantially higher local therapy control rate for HCC compared to colorectal metastases.

Adult↗

PubMed2000

Testing the impact attenuation of loose-fill playground surfaces.

OBJECTIVES: Our objective was to measure the impact attenuation performance of five types of loose-fill playground surfaces at a variety of drop heights, material depths, and conditions. METHODS: In a laboratory setting, an instrumented head form was dropped on varying depths of loose-fill materials at one foot height increments until critical deceleration values were exceeded. The effects of test box size, material temperature, and compression were also studied. RESULTS: Data suggest that a larger test box size influences test results. Uncompressed materials performed quite unexpectedly, that is, resilience did not necessarily increase with increasing depth of material and temperature did not have uniform effects. Compression before testing improved consistency of results. CONCLUSION: The current standard test procedure (ASTM F1292) appears problematic for loose-fill materials. Our results indicate that (1) shredded rubber was the best performer; (2) there was little difference between sand, wood fibers, and wood chips; and (3) pea gravel had the worst performance, making it a poor choice for playground surfacing.

Accidental Falls↗

PubMed2000

Mood state changes of students enrolled in physical activity classes.

74 students enrolled in physical activity classes completed the happiness and sadness scales of the Emotional Assessment Scale each week for the 7-week course. A repeated measures analysis of variance indicated no significant change in mean mood state scores. Subjects' scores remained fairly happy throughout the length of the course, women having significantly happier scores than men.

Adolescent↗

PubMed1999

[Therapeutic options in non-resectable liver metastases. Percutaneous radiological interventions].

In patients with irresectable liver metastases the following spectrum of oncological concepts is in use. Percutaneous interventional methods allows for an optimized local control rate in strictly intrahepatic disease. Regional short-term time chemotherapy and transarterial chemoembolization (TACE) belong to regional methods. As local ablative methods, intratumoral drug application, endotumoral chemotherapy and alcohol instillation can be used. The most promising thermotherapeutic strategies are radiofrequency and laser-induced thermotherapy (LITT). In a prospective study 278 patients suffering from liver metastases were treated with MR-guided LITT and exact data for the local control rate and survival rate were evaluated. The overall cumulative survival rate (Kaplan-Meier) of patients with liver metastases was 40.8 months (median: 40.97 months, 95% confidence interval 36.3-45.2).

Adult↗

PubMed1999

[Interventional MR-guided laser induced thermotherapy in oncologic indications. Status and prospects].

MR-guided LITT (laser-induced thermotherapy) is currently being evaluated for its effectiveness in clinical oncology. MR-guided LITT is defined as a minimally invasive technology based on the effects of the applied Nd-YAG laser on tumorous tissue. Due to specific characteristics of the laser-induced coagulative effect, online monitoring via MR thermometry is possible and extremely precise. In a period of 6 years 335 patients suffering from malignant soft tissue tumors were prospectively treated via MR-guided LITT. We evaluated the local tumor control rate, the rate of complications and the survival data from the clinical and MRI follow-up. Our results prove that MR-guided LITT results in a extremely low rate of side effects and an effective tumor control rate higher than 95%, depending on the size of the lesion. It is concluded that this therapeutic concept is of clinical value for patients with primary and secondary liver cancer, malignant lymph node involvement, abdominal recurrent tumors and tumors of the head and neck.

Adult↗

PubMed1999

Liver metastases: interventional therapeutic techniques and results, state of the art.

The liver is the most common site of metastatic tumour deposits. Hepatic metastases are the major cause of morbidity and mortality in patients with gastrointestinal carcinomas and other malignant tumours. The rationale and results for interventional therapeutic techniques in the treatment of liver metastases are presented. For the treatment of patients with irresectable liver metastases, alternative local ablative therapeutic modalities have been developed. Technique and results of local interventional therapies are presented such as microwave-, radiofrequency (RF)- and ultrasound ablation, and laser-induced interstitial therapy (LITT), cryotherapy and local drug administration such as alcohol injection, endotumoral chemotherapy and regional chemoembolisation. In addition to cryotherapy, all ablative techniques can be performed percutaneously with low morbidity and mortality. Cryotherapy is an effective and precise technique for inducing tumour necrosis, but it is currently performed via laparotomy. Percutaneous local alcohol injection results in an inhomogeneous distribution in liver metastases with unreliable control rates. Local chemotherapeutic drug instillation and regional chemoembolisation produces relevant but non-reproducible lesions. Laser-induced interstitial thermotherapy (LITT) performed under MRI guidance results in precise and reproducible areas of induced necrosis with a local control of 94%, and with an improved survival rate. Interventional therapeutic techniques of liver metastases do result in a remarkable local tumour control rate with improved survival results.

Antineoplastic Agents↗