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Biomedical subjects

K T Moesta

Publications and source records attributed to K T Moesta.

At least 19 recordsLinked to original sources

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device.

PURPOSE: To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy. MATERIAL AND METHODS: In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions. RESULTS: In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred. CONCLUSION: MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.

Adult↗

[Increasing abdominal pain caused by abdominal tumor in a 21-year-old female].

Lymphangiomas are congenital malformations which occur mostly in the neck and head region of children. They are rarely located in the mesenterium or retroperitoneum in adults. We present a case of mesenteric cystic lymphangioma in a young woman who was admitted to hospital with a history of increasing abdominal pain. We discuss diagnostic means, differential diagnosis, and therapeutic management of the disease.

Abdominal Pain↗

New concepts of staging in gastrointestinal tumors as a basis of diagnosis and multimodal therapy.

The therapy of gastrointestinal tumors is becoming more and more sophisticated and complex. This is due to an improved understanding of the pathogenesis of tumors, a more detailed classification and increasing therapeutic options. The basis of optimized therapeutic concepts is the exact evaluation of tumor spread and exact staging. The following review describes some of the most recent staging concepts in gastrointestinal tumors. Multislice computed tomography (CT), positron emission tomography (PET) and new supraparamagnetic iron oxide contrast agents for magnetic resonance imaging enable an increasing quality of the visualization of tumors and metastases. 3D imaging will be used for planning of surgical interventions in the future. Optical coherence tomography may contribute to an improved tumor staging and, thus, to the safety of limited interventions in early oesophageal- and gastric cancer patients. Laparoscopy and laparoscopic ultrasound become increasingly important for the identification of small metastases in the peritoneum, in lymph nodes and in the liver. The sentinel lymph node concept will contribute to an improved staging and individualized therapy as well.

Combined Modality Therapy↗

Outcome analysis of 189 consecutive cancer patients referred to the intensive care unit as emergencies during a 2-year period.

The referral of critically ill cancer patients to an intensive care unit (ICU) is a matter of controversial debate. This study was conducted by an interdisciplinary clinical group to evaluate the outcome of ICU treatment in cancer patients according to their characteristics at the time of referral. A retrospective analysis was used to identify relevant subgroups among 189 consecutive cancer patients referred as emergencies to one of four ICUs during a 2-year period. Reasons for ICU referral were pneumonia (29.6%), sepsis (27.0%), fungal infection (11.1%), another infection (9.5%), gastrointestinal emergency (16.9%), treatment-related organ toxicity (6.9%), or other, non-infectious complications (43.9%). Vasopressor support was required in 50.3%, mechanical ventilation in 49.7%, and haemodialysis/-filtration in 26.5% of the patients. Overall, 41.3% died during ICU treatment, 12.2% died after transfer from ICU to a non-ICU ward, and 35.4% were discharged alive. Sepsis, mechanical ventilation, vasopressor support, renal replacement therapy and neutropenia were independent risk factors for fatal outcome, but no single risk factor unequivocally predicted death. All patients with fungal infection who required vasopressor support and either had sepsis (n=13) or needed mechanical ventilation (n=14) died during ICU treatment, while all non-septic patients. who did not require mechanical ventilation, were younger than 74 years of age and had a non-infectious underlying complication (n=29), survived. This analysis may help to early identify relevant subgroups of cancer patients with different prognoses under ICU treatment. A prospective study to confirm the predictive usefulness of this approach is needed. Cancer patients should not be excluded from referral to the intensive care unit in an emergency solely due to their underlying malignant disease or a single unfavourable prognostic factor.

Adult↗

Protoporphyrin IX occurs naturally in colorectal cancers and their metastases.

Colorectal cancers exhibit a red fluorescence. The nature of the responsible fluorophore and its eventual diagnostic potential were investigated. Thirty-three consecutive colorectal resection specimen, 32 of which with histologically confirmed cancer, and a total of 1053 palpable mesenteric nodes were fluorimetrically characterized ex vivo. Furthermore, frozen material from 28 patients was analyzed, selected for the availability of primary tumor material and metastatic tissue, e.g., lymphatic and liver metastases from the same patient. Biochemical characterization was carried out through chemical extraction and reversed phase high-performance liquid chromatography. The fluorescence spectra of tissues, tissue extracts, and standard solutions of porphyrins were determined using a pulsed solid-state laser system for excitation and an imaging polychromator, together with an intensified CCD camera for time-delayed observation. Protoporphyrin IX (PpIX) was identified as the predominant fluorophore in primary tumors and their metastases. The fluorophore occurred in the absence of necrosis and in sterile locations. In untreated cases (n = 24), PpIX fluorescence discriminates metastatically involved lymph nodes from all other palpable nodes with a sensitivity of 62% at a specificity of 78% (P < 0.0001). After neoadjuvant treatment of rectal cancer, the PpIX fluorescence level of the primary tumors was reduced and a discrimination of lymph nodes based on PpIX-fluorescence was impossible. We conclude that colorectal cancer metastases accumulate diagnostic levels of endogenous PpIX as a result of a tumor-specific metabolic alteration.

Adult↗

[Staging and neoadjuvant therapy of squamous cell carcinoma of esophagus].

Once the diagnosis of esophageal cancer is established, the decision on treatment will depend on the stage of the disease. Since improvement of prognosis can only be expected in patients with complete removal of their tumor, preoperative staging plays a pivotal role in the decision-making process. Preoperative diagnostic procedures should define the tumor in its relation to the tracheal bifurcation (site), determine the depth of tumor invasion (T status), evaluate regional lymph node metastases (N1 disease) and exclude distant metastases (M1 disease). Endosonography represents currently the most accurate imaging technique for detecting the correct T stage over the correct N stage. A higher accuracy rate may be achieved by combining endosonography with other staging modalities such as computed tomography. Chest x-ray, and percutaneous ultrasonography (abdominal, neck) form the diagnostic basis in staging M1 disease. Computed tomography (neck, chest and abdomen) is currently the best method to detect metastases in the liver and in celiac nodes. Staging laparoscopy when combined with laparoscopic ultrasonography shows a higher sensitivity than ultrasonography and computed tomography in the diagnosis of smaller metastases and peritoneal seedings. En bloc esophagectomy together with the regional lymph nodes remains the treatment of choice in medically fit patients with localized esophageal carcinoma (Stage I-IIB, T1-T2/N0-N1/M0). Due to early involvement of mediastinal structures, curative resection is unlikely to be achieved in patients with locally advanced esophageal carcinoma (Stage III, T3-T4/N0-N1/M0). Most available data indicate that neoadjuvant radiochemotherapy leads in a significant number of patients to downstaging of the tumor, increases the rate of R0 resection, improves local tumor control, and prolongs the recurrence free interval. However, neoadjuvant radiochemotherapy resulted in a marked increase of morbidity and postoperative mortality without improvement of survival. At present, neoadjuvant therapy is still experimental and there is no consensus for an optimal treatment regimen. Its use outside of an investigational setting can not be recommended. Future research must focus on more effective and less toxic neoadjuvant modalities (e.g. new chemotherapy agents, hyperthermia).

Carcinoma, Squamous Cell↗

The role of transrectal ultrasound-guided biopsy in the postoperative follow-up of patients with rectal cancer.

BACKGROUND: The value of endorectal ultrasound (EUS) in the diagnosis of recurrent rectal cancer is limited by the inability to differentiate between malignant and benign lesions. We have prospectively investigated the role of EUS with transrectal ultrasound-guided biopsy in the postoperative follow-up of rectal cancer. METHODS: Since 1995, patients who had undergone a sphincter-saving operation for rectal cancer (n = 312) were followed-up by a standard program including rectal palpation, carcinoembryonic antigen monitoring, computed tomography, and EUS. Transrectal EUS-guided biopsy of perirectal lesions was performed in 68 patients with perirectal lesions by using a rigid endoprobe with a 10 MHZ multiplane transducer and special targeting device. RESULTS: Overall local recurrence was observed in 36 patients. Intraluminal recurrence was diagnosed by proctoscopy in 12 patients. Transrectal EUS-guided biopsy showed pelvic recurrence in 22 of 68 patients with perirectal lesions. Biopsy specimens with benign histology were obtained from 41 patients, and the procedure failed in 5 cases (accuracy, 92%). There was a strong agreement between transrectal biopsy results and the final diagnosis (kappa = 0.84), the sensitivity and specificity being 91% and 93%, respectively. In contrast, clinical examination (kappa = 0.27), computed tomography (kappa = 0.47), or EUS (kappa = 0.42) showed only a moderate level of agreement with the histopathologic diagnosis, mainly because of the limited specificity of all 3 methods (65% vs 46% vs 57%). EUS-guided biopsy was significantly more accurate than computed tomography and EUS (P <.01). The biopsy results had a considerable impact on the management in 18 of 68 patients (26%). CONCLUSIONS: Transrectal EUS-guided biopsy is a safe and efficient method for tissue sampling of perirectal lesions. This minimally invasive and inexpensive technique improves the accuracy of endorectal ultrasound in the diagnosis of recurrent rectal cancer.

Biopsy↗

Histopathological correlation to MRI findings during and after laser-induced thermotherapy in a pig pancreas model.

RATIONALE AND OBJECTIVES: To investigate whether percutaneous laser-induced thermotherapy (LITT) with continuous magnetic resonance (MR) monitoring of thermal effects within the pancreas is feasible in a porcine model. METHODS: Laser applicators were placed in the pancreas of 15 female pigs. A temperature-sensitive (thermo--fast low-angle shot) sequence was used for continuous monitoring of thermal effects during LITT at 1.5 T. Follow-up MR images were acquired, the pigs were observed for 7 days, and then a pathological examination was performed after sacrifice. RESULTS: Continuous MR monitoring visualized thermal effects in pancreatic tissue and thermal damage of the spleen (n = 1), the left kidney (n = 1), and peripancreatic fat (n = 4) but missed the thermal damage of the duodenum (n = 2). Thermal-induced lesions (10--32-mm diameter) were clearly visualized on contrast-enhanced T1-weighted images. CONCLUSIONS: Laser-induced thermotherapy of pancreatic tissue was feasible in this porcine model, and online monitoring was practicable. Further studies are necessary to increase the accuracy of online MR imaging of thermal effects.

Amylases↗

Near-infrared fluorescent dyes for enhanced contrast in optical mammography: phantom experiments.

Optical mammography with near-infrared (NIR) light using time-domain, frequency-domain, or continuous-wave techniques is a novel imaging modality to locate human breast tumors. By investigating excised specimens of normal and diseased mamma tissue we were able to demonstrate that differences in their scattering properties are a poor predictive parameter for normal and diseased mamma tissue. This paper describes the application of a NIR dye to improve the differentiation between breast tumors and normal tissue in a rat model. The NIR dye furnished a high tumor-to-tissue contrast ratio (6:1) in fluorescence images. Furthermore, this dye was used to develop liquid scattering phantoms with absorbing and fluorescent inhomogeneities. Using frequency-domain and time-domain instrumentation these inhomogeneities were localized at sufficient contrast by their increased absorption and fluorescence. Contrast between inhomogeneities and surrounding medium could be improved by combining fluorescence and transmittance images.

Breast Neoplasms↗

Fluorescence as a concept in colorectal lymph node diagnosis.

Fluorescence detection may constitute an appropriate means in gastrointestinal cancers to diagnose lymphatic tumor spread as opposed to gamma-scintillation methods. Photodiagnostic tracers have been shown to localize rapidly in malignant cells and may enable sensitive detection of small cell aggregates in lymph nodes. To reach a detection depth of several millimeters, a broad banded unspecific tissue autofluorescence may be controlled by so-called background subtracting techniques, generally based either on fluorescence observation at several wavelengths or on dual-wavelength fluorescence excitation. Using such comparative fluorescence detection techniques, some tumor entities can be differentiated soley based upon autofluorescence characteristics. Introducing a further enhancement in sensitivity for longer life-time fluorophores by time delayed fluorescence detection we ran a pilot trial comprising 174 lymph nodes from colorectal cancer specimen from 9 patients. Metastatically involved lymph nodes could be differentiated from all other palpable nodes in the mesenteric fat at a specificity of 85% with a sensitivity of 65%. Specific fluorescence features may be useful to preselect tissue samples for further histological analysis.

Aminolevulinic Acid↗

Telemedicine: the new must for surgery.

The vision of telesurgery comprises a multitude of new communicative elements influencing the way surgeons will treat their patients in the future. The first prerequisite for effective telecommunication is to digitize surgical data. Many medical imaging modalities provide primarily digital data sets, and digital image communication is already entering clinical practice under the labels of teleradiology and telepathology. However, for any surgical purpose, images must refer to tissues. Three-dimensional image reconstruction is warranted, and if such data shall be useful during surgery, different image sources must be combined into some virtual, multiparametric body model and matched to an intraoperatively distorted organ contour. A multitude of detail problems arise, beginning with image standards, data interfaces, data transport, image fusion, registering, contour matching, and, once the data are integrated, all the aspects of surgery-suitable data display and interaction. We refer here to several demonstration projects illustrating such a complex surgical data set and its interactive telecommunication. In all instances, telecommunication was to enable a concentration of distributed medical intelligence at the site where the patient was treated. With further technological development, such telesurgical applications will have a growing influence on patient management and surgical decision making. In the very near future, computer-aided navigation and robotic assistance, based on the same surgical data sets, will be available to all fields of surgery. How decisive the role these methods will play for specific procedures or diseases needs to be determined.

Computer Simulation↗

[Foreign body-induced thoracic actinomycosis as differential mediastinal space-occupying lesion diagnosis].

Thoracic actinomycosis is a rare disease often mistaken for malignancy. Untreated actinomycosis is associated with high mortality, the disease should, thus, be considered early. We report the case of a 58-year-old male patient who was referred to us for a suspected thoracic sarcoma. He had 6-month a history of hemoptysis, and there was severe deterioration in his general health. Only in a roundabout way was the diagnosis of thoracic actinomycosis established; it was caused by an aspirated chicken bone, as found by bronchoscopy. All symptoms rapidly regressed by antibiotic therapy and definitive healing was obtained. In the diagnostic work up of thoracic masses that may represent inflammatory diseases, lymphoma, thymus-associated, sarcomatous and germ-cell tumors, bronchoscopy is of primary diagnostic importance.

Actinomycosis↗

Local excision of rectal cancer through windowed specula: long-term results.

Transanal local excision of rectal cancer has been advocated as a curative option in patients with early rectal cancer and for patients unsuitable for radical surgery. We report our long-term experience with an easy-to-use and inexpensive technique based on windowed specula. From 1982 to 1994, 137 patients with rectal cancer were treated by local excision with curative intention. An R0 resection was possible in 74% of all patients and in 80% of the patients with a tumor surface of less than 9 cm2. Ninety patients with a follow-up of more than 3 years (T1: n = 50, T2: n = 30, T3: n = 14) were evaluated for survival. Seventy-four of these 90 patients are currently alive. The cause of death is known for all 16 deceased patients. In 4, death was tumor-related; 3 of these patients had a component of local failure. In 6 of 8 patients with local recurrence, a radical reresection was possible. The rate of recurrence increased with T category and with tumor grade. There has been one recurrence in a patient with a T1G1 cancer. The instrumentation enables adequate local excision of rectal cancers of less than 9 cm2 surface area. In this group of patients including a considerable number with T2 and T3 cancers, only 3 died of tumor-related causes with a component of local failure, which compares well with mortality rates above 4% for abdominoperineal excision. Comparison with international data on radical surgery shows that the overall survival is not reduced by local transanal excision for early rectal cancer.

Adult↗

Seromuscular spiral cuff perineal colostomy: an alternative to abdominal wall colostomy after abdominoperineal excision for rectal cancer.

Seromuscular spiral cuff perineal colostomy may be an alternative to abdominal wall colostomy after abdomino-perineal excision. We present our initial experience with the procedure in 13 patients operated upon between March 1993 and December 1997. Patients undergoing abdomino-perineal excision for rectal cancer, under 65 years of age, without severe concomitant disease, and strongly motivated to comply with an intensive postoperative physiotherapy were selected. The neosphincter procedure comprised a pull-through of a sufficient length of well-vascularized colon, 12 cm of which was then cleared of fat. In this segment, the seromuscular layer was separated from the mucosa, cut into a longitudinal sheet and wrapped in spirals around the colon at its perineal insertion. One patient died from pulmonary embolism. A second patient suffered from ischemic necrosis of the distal colon and lost his neosphincter. Minor complications included one stenosis, corrected by surgery, and one iatrogenic lesion on rectoscopy at another institution. No patients experienced local recurrence, while four patients presented distant metastases. Initially, all patients suffered from incontinence. After 6 months, 6 of 11 evaluable patients showed total and 5 showed partial continence.

Abdominal Muscles↗

Frequency-domain techniques enhance optical mammography: initial clinical results.

We present a novel approach to optical mammography and initial clinical results. We have designed and developed a frequency-domain (110-MHz) optical scanner that performs a transillumination raster scan of the female breast in approximately 3 min. The probing light is a dual-wavelength (690 and 810 nm, 10-mW average power), 2-mm-diameter laser beam, and the detection optical fiber is 5 mm in diameter. The ac amplitude and phase data are processed with use of an algorithm that performs edge effect corrections, thereby enhancing image contrast. This contrast enhancement results in a greater tumor detectability compared with simple light intensity images. The optical mammograms are displayed on a computer screen in real time. We present x-ray and optical mammograms from two patients with breast tumors. Our initial clinical results show that the frequency-domain scanner, even at the present stage of development, has the potential to be a useful tool in mammography.

Algorithms↗

Frequency-domain optical mammography: edge effect corrections.

We have investigated the problem of edge effects in laser-beam transillumination scanning of the human breast. Edge effects arise from tissue thickness variability along the scanned area, and from lateral photon losses through the sides of the breast. Edge effects can be effectively corrected in frequency-domain measurements by employing a two-step procedure: (1) use of the phase information to calculate an effective tissue thickness for each pixel location; (2) application of the knowledge of tissue thickness to calculate an edge-corrected optical image from the ac signal image. The measurements were conducted with a light mammography apparatus (LIMA) designed for feasibility tests in the clinical environment. Operating in the frequency-domain (110 MHz), this instrument performs a transillumination optical scan at two wavelengths (685 and 825 nm). We applied the proposed two-step procedure to data from breast phantoms and from human breasts. The processed images provide higher contrast and detectability in optical mammography with respect to raw data breast images.

Biophysical Phenomena↗