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K C Klose

Publications and source records attributed to K C Klose.

At least 19 recordsLinked to original sources
PubMed1996

Pattern recognition system for focal liver lesions using "crisp" and "fuzzy" classifiers.

RATIONALE AND OBJECTIVES: To determine the diagnostic performance of an artificial intelligence system for classification of focal liver lesions, in comparison to human observers. METHODS: One hundred forty-three focal hepatic lesions were evaluated with dynamic computed tomography. The study comprised 59 hemangiomas, 24 other benign lesions (focal nodular hyperplasia, adenoma), and 60 malignant liver lesions (18 primary, 42 secondary). All lesions but the hemangiomas were histologically examined by needle biopsy. For delineation of the lesion, a region of interest was defined interactively. The pattern recognition was performed in two steps with initial extraction of textural features: training of a classifier and classification of the lesions. The accuracy of classification of hepatic lesions into three groups (hemangioma, other benign processes, malignant lesions) was tested. The results were compared with those achieved by human observers using receiver operating characteristic statistical analysis. RESULTS: The accuracy (total rate of correct diagnoses) was 90.2%. False classifications were found owing to small size, weak contrast enhancement after bolus injection, respiratory movement, and atypical morphology of the lesion. The area under the receiver operating characteristic curve was not significantly different for computer and human observers. CONCLUSIONS: The system demonstrated a diagnostic accuracy comparable to human observers. Further improvement with increasing numbers of typical computed tomographic series for training of the classifier can be expected.

Adenoma↗
PubMed1995

Artificial widening of the mediastinum to gain access for extrapleural biopsy: clinical results.

PURPOSE: To assess the utility of artificial widening of the extrapleural space to gain an extrapleural biopsy access route to the anterior and posterior mediastinum. MATERIALS AND METHODS: The authors retrospectively analyzed the findings in 20 patients who underwent biopsy of mediastinal masses after dilation of the extrapleural space with injection of approximately 20 mL of physiologic saline solution. The solution was injected to provide ventral (n = 6) or dorsal (n = 14) extrapleural access to the mediastinum. Biopsies were performed under computed tomographic guidance. RESULTS: Right-sided paravertebral extrapleural access to the mediastinum was achieved in 11 of the 14 patients in whom a dorsal approach was used. The paravertebral extrapleural soft tissue was dilated from a mean of 0.2 cm to a mean of 0.9 cm. Extrapleural biopsy was performed in nine patients. The pleura was traversed in four patients, causing pneumothoraces in two. A parasternal access route was created in all six patients in whom a ventral approach was used, and biopsies were performed without complications. The minimal width of the anterior mediastinum in these six patients increased from a mean of 2.8 cm to a mean of 4.6 cm with dilation. CONCLUSION: Artificial widening of the extrapleural space provides an access route to the anterior and posterior mediastinum for large-bore biopsy.

Adult↗
PubMed1993

[Dynamic inversion recovery snapshot FLASH MRT of focal nodular hyperplasia of the liver].

11 lesions of focal nodular hyperplasia (FNH) in 6 patients were studied by means of dynamic snapshot-FLASH MRI before and after bolus injection of Gd-DTPA. In addition, plain snapshot-FLASH images were compared with T1- and T2-weighted spin-echo (SE) images and with T1-weighted breathhold-FLASH images. Highest FNH-liver signal-difference-to-noise ratios were obtained with snapshot-FLASH followed by T2-SE. In all patients contrast-enhanced serial snapshot-FLASH demonstrated reliably the typical haemodynamic appearance of FNH known from dynamic computed tomography. Because of its high intrinsic lesion-liver contrast and high time-resolution dynamic snapshot-FLASH MRI may facilitate differential diagnosis of hepatic tumours.

Adult↗
PubMed1993

[The diagnosis of focal liver lesions by the texture analysis of dynamic computed tomograms].

Characterisation of focal liver lesions on computed tomography (CT) depends on correct interpretation of morphology and dynamic changes during bolus injection of contrast medium. The aim of this study was to develop a texture analysis concept for computer based interpretation of dynamic CT images. 148 focal liver lesions were investigated by serial CT. The study comprised 61 haemangiomas, 25 other benign lesions (FNH/adenomas) and 62 malignant lesions (primary or secondary). FNH, adenomas and malignant lesions were histologically proven. Diameter was 8-145 mm (mean 31 mm). Regions of interest were interactively defined. After extraction of characteristic textural features, a pattern classifier was trained. All CT series were evaluated using the "leaving-one-out" method. 134 of the 148 lesions were correctly classified (positive predictive value 0.9). Sensitivity for the presence of malignancy was 0.93 (80/86), specificity was 0.9 (56/62). False classification of a lesion was found to depend strongly on the quality of the examination (bolus intensity, positional change of the lesion due to respiratory movements).

Diagnosis, Differential↗
PubMed1992

[MR tomography of colorectal diseases with a negative rectal contrast medium].

The potential of the generic kaopectate (Upjohn) as a negative rectal contrast agent in MR imaging was investigated in the assessment of colorectal disease. 45 MR examinations in patients with colorectal disease (colorectal carcinoma 25 patients, inflammatory disease 12 patients, miscellaneous disorders of the colon 8 patients) were evaluated. All examinations were performed with T1 and T2 weighted SE sequences after rectal application of kaopectate. Gd-DTPA enhanced T1 SE sequences were obtained as well. Kaopectate revealed a signal void of the lumen of the large intestine in T1 and T2 weighted SE sequences. Intravenous administration of Gd-DTPA enabled good differentiation of contrast-enhanced malignant or inflammatory tissue and the low signal lumen of the bowels. No side effects were noted.

Adult↗
PubMed1992

[CT-guided Tru Cut biopsy of solid pelvic space-occupying lesions. The indications, technic and results].

Solid lesions in different localisations of the pelvis were biopsied with a large-bore Tru-Cut cannula (G 14) in 88 patients under computed tomographic guidance. Special techniques for safe access to pelvic lesions are described. Indications for biopsy were suspected extraluminal tumour recurrence (n = 49), masses outside the pelvic organs in the absence of a known pelvic primary (n = 21) and in the presence of a known pelvic primary (n = 10). In 8 cases, lesions situated within pelvic organs were punctured. Without any repeat biopsy, accuracy reached 96.6%, sensitivity was 95.2% and specificity was 100%. In comparison to the results of FNA reported in the literature diagnostic accuracy can be improved upon by using large-bore biopsy. No complications occurred.

Anesthesia, Local↗
PubMed1992

[Percutaneous CT-controlled cutting-needle biopsy of diffuse interstitial and alveolar lung diseases--the technic and results].

Twenty-three patients underwent CT-guided large-bore biopsy of diffuse lung disease of clinically and radiologically indeterminate etiology. The procedure was preceded by negative transbronchial biopsy in 20 cases. CT-guided biopsies were performed with a 14-gauge Trucut-needle. Obtaining at least 3 specimens of different parts of the diseased area, a correct histologic diagnosis was achieved in all cases. The size of the histologic specimens (mean: 5-6 mm) exceeded that of the specimens obtained by transbronchial biopsy as reported in the literature. Two major complications occurred and included a rapidly developing tension pneumothorax treated by a small-bore catheter and one self-limited hemoptysis. Major advantages of percutaneous CT-guided biopsy are the nonsuperimposed and very sensitive imaging of lung alterations in diffuse lung diseases that allows evidence of adjacent less and more involved areas accessible by one biopsy approach. CT-guided large-bore biopsy with a cutting needle seems to be a very promising, accurate method in the pathomorphologic work-up of diffuse lung diseases rendering open biopsy unnecessary in many cases.

Adult↗
PubMed1992

[CT-guided large-bore biopsy of solid non-organ-bound space-occupying lesions in the retroperitoneum].

Seventy-eight solid, non-organic retroperitoneal tumours were biopsied with a 14-gauge Tru-Cut needle in 73 consecutive patients with the exception of one. Adequate material was not obtained in only one patient with the primary known (1.3%). In the adequate material (98.7%), the dignity of all lesions was accurately determined and 93.1% of lesions were accurately classified. Typing accuracy reached 100% in histologically known primaries (n = 31) and 87.8% in histologically unknown primaries (n = 41). A hypertensive crisis and a small haematoma following biopsy of an inadvertent extra-adrenal phaeochromocytoma was the single complication found in this series. An arterial bleeding following biopsy was prophylactically embolised through the biopsy needle. CT-guided large-bore biopsy of solid non-organic retroperitoneal tumours is a safe, non-invasive procedure with a high diagnostic yield that obviates the need for open diagnostic procedures in a large number of cases.

Adolescent↗
PubMed1992

[A hypervascular adrenal adenoma. A differential diagnostic problem in dynamic CT and MRT].

At dynamic CT, Gd-DTPA-enhanced MRI, and digital subtraction angiography, a large adrenal adenoma verified by resection histology presented as a hypervascular tumor. In all imaging modalities, it showed a strong patchy enhancement during the early phases of the passage of contrast media and subsequent intralesional contrast equilibration. This case demonstrates that even high enhancement does not rule out an adrenal adenoma with certainty. In the oncologic patient, therapeutic decisions should not be made on the basis of the contrast behavior of an adrenal lesion alone.

Adenoma↗
PubMed1992

[Percutaneous catheter drainage of a thyroid abscess under CT control].

A large cervical abscess originating from the thyroid gland was treated by means of irrigational catheter drainage performed percutaneously with CT guidance. Culturing resulted in the growth of Streptococcus. Catheter drainage associated with appropriate antibiotic therapy resulted in healing of the abscess after only 3 days with no complications occurred. This case suggests that CT-guided percutaneous catheter drainage may be an effective and safe alternative to surgical therapy in the neck area as well as in other regions of the body.

Abscess↗
PubMed1991

[Contrast-enhanced MRT of malignant melanoma of the uvea].

Twenty-one patients with malignant melanoma of the uvea or iris, some with intra-ocular bleeding, were examined by MRT before and after the administration of Gd/DTPA. In 13 patients, several examinations were performed over a period of 1.5 to 20 months after irradiation of the melanoma. After Gd-DTPA there was an average increase of 13% in the signal intensity from all non-irradiated melanomas (17 cases). Three months following radiation therapy, there was an average increase in signal intensity after Gd-DTPA of 65.7%, and after seven months of 100%. Amelanotic melanomas (two cases) showed a primary increase in intensity of 100%. Two melanomas of the iris were demonstrated by sonography; of these, only one could be shown with certainty by MRT. Small tumours and tumour residues after irradiation were better defined after contrast. In the presence of suspected intra-ocular bleeding, the examination should always be performed after the administration of Gd-DTPA.

Adult↗
PubMed1991

[The computed tomography of malignant otitis externa].

Computed tomography was performed preoperatively in 20 patients suffering from malignant external otitis. The CT findings were nearly completely confirmed by the intraoperative findings. A circumscribed or diffuse thickening of the cartilaginous wall of the external auditory canal and an inflammatory infiltration of the subtemporal fossa are, in combination, most suspicious signs of malignant external otitis. Computed tomography enables detailed information on the extension of the pneumatic system and the grade of involvement of bones and soft tissues in malignant external otitis. A modified classification of malignant external otitis based on computed tomographic findings is proposed.

Adult↗
PubMed1991

[CT-guided course-punch biopsy of the adrenals. The indications, technic and results].

Adrenal lesions exceeding 1.5 cm diameter were biopsied with a Tru-Cut needle (G 14) under CT guidance for histologic evaluation in 61 patients. Using CT for guidance, special techniques for safe access to the adrenals are described. Large-bore biopsy yielded a sensitivity of 100% and a specificity of 97.4%. Diagnostic accuracy was 98.3%. No significant complications occurred. In comparison to the results of FNA reported in the literature, large-bore biopsy of adrenal lesions improves the rate of adequate material and the histopathologic differentiation without increase of complications.

Adrenal Gland Neoplasms↗
PubMed1991

[The accuracy of plain-film radiology in demonstrating the shadows of the pneumatic spaces of the skull--a comparison with computed tomography].

The accuracy of plain-film radiography in the diagnosis of opacities of the pneumatic system of the skull was evaluated in 302 patients in comparison with computed tomography. Plain films were performed using standard projections (Schüller, Stenvers, NNH o.n., paranasal sinus). Concerning the paranasal sinuses sensitivity of plain film radiography ranged from 36.7 to 66.4% depending on localisation. In the mastoid, a sensitivity of only 35% was found. Specificity was high (90% and over) with the exception of the maxillary sinus (82%). More sensitive, noninvasive diagnostic imaging techniques are indicated in the following conditions: therapy-refractory opacification of one sinus, indeterminate otological symptoms in the presence of a low pneumatized mastoid, and definitive exclusion of infectious foci in the pneumatic system of the skull.

Bone Diseases↗