PubMed Health⌕ Search

Biomedical subjects

K Hergan

Publications and source records attributed to K Hergan.

At least 19 recordsLinked to original sources
PubMed2002

Diffusion-weighted MRI in diffuse axonal injury of the brain.

The goal of this study was to identify and describe the different types and patterns of tissue injury which are encountered by diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) of the brain. The DWI data sets of 98 patients who suffered from a closed-head injury were retrospectively evaluated. Medical records were reviewed to rule out pre-existing neurological diseases. Lesions were studied for their DWI signal characteristics and lesion size or extension. Traumatic lesions were classified into three categories depending on their signal characteristica on DWI and apparent diffusion coefficient (ADC) maps: type 1, DWI- and ADC-hyperintense most likely representing lesions with vasogenic edema; type 2, DWI-hyperintense, ADC-hypointense indicating cytotoxic edema; type 3, central hemorrhagic lesion surrounded by an area of increased diffusion. According to the size and extent of lesions, injury was classified into three groups: group A, focal injury; group B, regional/confluent injury; and group C, extensive/diffuse injury. Our study showed that diffusion-weighted imaging differentiates between lesions with decreased and increased diffusion in patients with DAI. Different degrees of tissue injury extent were noticed. Future prospective studies should study if this additional information can be used as a predictor of injury reversibility, final outcome and prognosis.

Adolescent↗
PubMed2002

[Implementation of BIRADSTM together with an organization of percutaneous breast biopsies: experiences, reactions].

PURPOSE: To record the acceptance and reactions of radiologists and physicians who recommend patients for mammography after simultaneous establishment of BIRADS TM and a registration of the results of percutaneous breast biopsies. MATERIALS AND METHODS: To improve clarity of mammographic reports and to provide guidance concerning any necessary percutaneous breast biopsies the Breast Imaging Data And Reporting System (BIRADS TM) has been introduced regionally together with a registration of percutaneous breast biopsies. Using a questionnaire, 25 radiologists and 230 referring physicians were asked on acceptance and reactions concerning the established system. RESULTS: Of the 15 answering radiologists, 93 % considered BIRADS TM a worthwhile effort and 87 % found the biopsy guidelines to be useful. They regarded the acceptance of the referring physicians and patients as high (80 %). Up to 69 % of the 52 participating physicians stated a better understanding of the mammographic reports, an easier comprehension of the dignity classification of a mammographic lesion and the feeling of an improvement in their work. Preoperative assessment of histology was found to be valuable by 94 % of the referring physicians. They believe that more than half of the patients benefit from the biopsy guidelines and that the majority of patients accept this approach. CONCLUSION: BIRADS TM is useful to standardize and improve mammographic reports. It is advantageous to link BIRADS TM with guidelines for percutaneous breast biopsies.

Attitude of Health Personnel↗
PubMed2001

The value of intraoperative angiography in surgery of intracranial aneurysms: a prospective study in 126 patients.

The value of intraoperative digital subtraction angiography in surgery for intracranial aneurysms, the benefits and cost-effectiveness are a matter of discussion. We prospectively studied 126 patients with 144 aneurysms, most on the anterior intracranial circulation, who underwent clipping and intraoperative angiography. Follow-up was 28.4 +/- 13.1 months. We tried to work out the indications for intraoperative angiography of the anterior circulation and its cost-effectiveness. In 10.3 % of patients (9 % per aneurysm) unexpected findings were shown by intraoperative angiography: inadequately clipped aneurysms in 10 (7.9 %), a completely unclipped aneurysm in one (0.8 %) and occluded major arteries in two (1.6 %). A broad neck was a variable of statistical significance for inadequate clipping or stenosis or occlusion of an adjacent vessel. There was a strong trend for aneurysms more than 15 mm in diameter to be "risky". Their site was not a predictive factor. We believe that intraoperative angiography is indicated in surgery not only on large and giant aneurysms, but also broad-based aneurysms of the anterior cerebral circulation regardless of their size. It is cost-effective compared to postoperative angiography. The rate of stroke in our hands was 0.8%.

Adult↗
PubMed2001

Heart luxation through a right-sided traumatic pericardial defect.

A traumatic defect of the pericardium is a rarely diagnosed entity. We present a patient with a right-sided luxation of the heart which was incidentally diagnosed during a thoracic CT performed for other reasons. Despite of the threatening strangulation of the great vessels, the patient had a stable circulation until surgical repair of the pericardial defect.

Adult↗
PubMed2001

[Advanced breast biopsy instrumentation (ABBI) experiences and critical comments].

UNLABELLED: Advanced breast biopsy instrumentation (ABBI) experiences and critical comments. PURPOSE: To describe our three-years' experience with advanced breast biopsy instrumentation (ABBI). MATERIALS AND METHODS: Considering lesion size, type and location as well as patient specific criteria 89 patients were selected for an ABBI. The documented data like duration, complication and change of the procedure, size of the lesions and biopsy cannulas, histologic outcome and further treatment were analysed retrospectively. RESULTS: ABBI was successful in 63 of 89 patients. Cancer was found in 18 patients (29 %) with a surgical re-excision to achieve tumour-free margins in 89 %. 45 patients had benign lesions (71 %) with a benign to malignant ratio of 2.5 : 1. ABBI was unsuccessful or had to be replaced by other biopsy techniques in 26 patients (29 %). In four of these patients the localization needle was already placed. Analysing the three-year period ABBI frequency dropped each year with an overall reduction of 63 %. Despite a good benign to malignant ratio the surgical re-excision rate in cancer patients is disappointing. Although using precise selection criteria for ABBI the rate of failed biopsies and changeover to another biopsy procedure was too high. The reduction of ABBI procedures during the three-year period is assumed to be an expression of the negative experiences with the method but also a refusal of the assigning colleagues to use ABBI. CONCLUSION: For the evaluation of suspected breast lesions ABBI is too invasive and too expensive. On the other hand ABBI is too ineffective as a therapeutic tool to remove suspected lesions. Therefore it is not warranted to use ABBI instead of other concurrent biopsy techniques.

Adult↗
PubMed2001

[Practical usage of a quality management system according to ISO 9001 : 2000 focusing on the double contrast (barium) enema].

PURPOSE: We describe the implementation of quality improvement measures in a quality management system. METHODS: With questionnaires for radiologists and patients, we investigated the relations between patient preparation and diagnostic quality serving the main purpose, to improve diagnostic quality with the help of more detailed patient information (e.g., changing preparation sheets and handling out "peri-med" information sheets to the patients). Furthermore, a comparative data ascertainment at other institutes was integrated. RESULTS: For the group of outpatients, increasing process quality (patient information) and outcome (diagnostic quality) could be achieved. Taking aspects of quality costs into consideration, a decrease in costs due to failures was achieved. CONCLUSION: More detailed patient information has positive effects on diagnostic quality of the double contrast (barium) enema.

Attitude of Health Personnel↗
PubMed2001

Gliomatosis cerebri: intra vitam stereotactic determination in two cases and review of the literature.

Gliomatosis cerebri (GC) is an infiltrative neoplastic process that is diffusely distributed through neural structures, whose anatomical configuration remains intact. Most of the cases with GC reported in the literature were diagnosed at autopsy (101/110, 92%). We report two cases of GC in a 42-year-old woman and a 65-year-old man. The diagnosis was confirmed neuropathologically after MRI-guided stereoetactic biopsy. External radiation therapy was performed and led to a complete recovery of all clinical signs. Follow-up examinations 17 and 21 months after diagnosis showed permanent reversal of all clinical and radiological signs. MRI should be used as a primary imaging study in the evaluation of GC and for the determination of the target points for stereotactic biopsy. We discuss the aetiology, clinical manifestation, difficulties of intra vitam diagnosis, and management of this rare condition in the light of other 110 (101 postmortem and nine intra vitam) reported cases of GC in the literature.

Adult↗
PubMed2000

Acetabular ossicles: normal variant or disease entity?

Ossicles located in the acetabular fossa may confuse diagnostic and therapeutic work-up. An accessory ossification centre may persist unfused as an os acetabuli centrale which is surrounded by intact hyaline cartilage representing an anatomic variant. Bone islands located in the pillars of the acetabulum can project into the acetabular fossa simulating acetabular ossicles. Osteochondrosis dissecans, posttraumatic articular bodies, degenerative disease and other rare lesions may be responsible for clinical symptoms and are of similar appearance than anatomic variants. Plain film radiography, X-ray tomography, CT and MRI are used to categorize these lesions. MRI is very valuable to assess cartilage integrity in a noninvasive way, but arthro-CT or arthro-MRI have to be used in unclear cases. Therefore the purpose of this presentation is to discuss the appearance, the possible etiology and the differential diagnosis of acetabular ossicles and how they can be evaluated to avoid an unnecessary arthrotomy.

Acetabulum↗
PubMed2000

[Implementation of the quality management system ISO/CD2 9001-2000 in a radiology institute].

Quality assurance in health care, a relatively new discipline, has developed rapidly over the last years and is now required by law. The Quality Management System (QMS) ISO 9001 aims at the definition of requirements necessary in order to achieve perfect products and continuous quality improvement. Implementation of this QMS necessitates the analysis and written documentation of all working processes and modes of operation. Furthermore, potential improvement possibilities are defined to guarantee highly qualified, generally applicable and standardised procedures. Time-consuming data assessment is an instrument to enable disclosure and analysis of existing errors as well as to show possibilities of optimization, thus forming the basis for continuous improvement. The new ISO NORM 9001-2000 is process-orientated with an organisational structure strongly recommendable for service institutions and therefore also for a department of radiology.

Academies and Institutes↗
PubMed1999

Chest ultrasound in diagnosis of pulmonary embolism in comparison to helical CT.

UNLABELLED: To many people die because of undiagnosed pulmonary embolism. Common pulmonary embolism is the most unexpected mortal event in necropsy, antemortem correctly diagnosed in 18-39%. The diagnostic value of chest ultrasound (CUS) has been investigated. METHODS: 117 (68 women, 49 men) patients with clinical suspicion of pulmonary embolism underwent chest sonography and spiral computed tomography (CT). Final diagnosis has been made by CT respective with echo-cardiography, venous duplex sonography and fibrin dimer tests. RESULTS: Finally, 70 patients suffered from pulmonary embolism. The chest sonograms showed averaged 1.5 x 2.8 cm (0.5-8.5) large triangular or rounded hypoechoic lesions, mean 2.6 pro patient, similar in form and size as in CT. Fresh reperfusionable infarcts were homogenous and hypoechoic. Older infarcts were well demarcated, mainly wedge shaped. A hyperechoic reflex in the center corresponds to the bronchiole: a sign of segmental involvement. The sensitivity of chest ultrasound was 94%, the specificity 87%, positive predictive value 92%, negative predictive value 91%, accuracy 91%. Overall 61 patients had PE in CT, in 47 (67%) cases a direct emboli detection was possible. 14 patients had peripheral lung consolidations without detectable emboli, but fibrin-dimer tests were positive in all cases, there was deep vein thrombosis diagnosed and they showed signs of PE in echocardiography. Spiral CT showed a sensitivity of 85%, a specificity and a positive predictive value of 100%, a negative predictive value of 83% and an accuracy of 92%. CONCLUSION: CUS can improve diagnosis of pulmonary embolism. Sonography also reveals small infarcts which remain undetected with other imaging procedure such as helical CT.

Adult↗
PubMed1998

[Contrast-enhanced subtraction MRT in the spin-echo technic].

PURPOSE: The aim of the retrospective study was to determine whether subtraction of spin-echo images is useful for estimating intensity and extension of contrast enhancement when practised in daily routine diagnostic work. METHODS: 348 patients with different diseases of the musculoskeletal and neuro system were examined with MRI using a T1-weighted spin-echo sequence before and after application of 0.1 mmol/kg Gd-DTPA with subsequent subtraction of both measurements. Usefulness of the source images, pictorial quality of subtracted images and intensity of contrast enhancement were assessed subjectively. RESULTS: Subtracted images were of sufficient quality in 85% of the cases, whereas source images were always usable except in 9 patients. It was easier to visualise the extent of contrast enhancement in subtracted than in non-subtracted images in examinations of the musculoskeletal system, whereas there was no difference in the neuro system. Contrast enhancement could definitely be excluded in 15% of the patients and was stated to be of low, medium and high intensity in 21%, 45% and 19%, respectively. In comparison with subtracted images lesions were stated to appear larger in 62% and 87%, smaller in 25% and 13%, and of the same size in 13% and 0% for T2-weighted and fat-suppressed images, respectively. CONCLUSION: Subtraction of spin-echo images before and after application of contrast media is useful for estimating intensity and extension of contrast enhancement without essentially increasing time and costs of the examination. Extension of contrast enhancement in musculoskeletal lesions rarely correlates with the extension of signal changes in T2-weighted and fat-suppressed images.

Adolescent↗
PubMed1997

Pitfalls in sonography of the Gamekeeper's thumb.

The gamekeeper's or skier's thumb is a very common injury. Nondisplaced tears of the ulnar collateral ligament of the thumb (UCL) may be treated conservatively. For that reason an accurate diagnosis is mandatory for choosing the correct therapy. Ultrasound is able to depict the position of the torn UCL correctly in approximately 90 % of cases. Sonographic pitfalls can be caused by a dislocation of the palmar joint capsule to the ulnar joint space, by a scalloping of the adductor aponeurosis due to the displaced UCL, and by scar tissue or technical mistakes. It is important to know about those pitfalls because conservative treatment of displaced UCL tears leads to instability. Therefore, the use of MRI is recommended whenever a nondisplaced UCL tear is suspected by US and a conservative therapy is suggested. Splitting the diagnostic pathway between US and MRI and preferring conservative therapy in nondisplaced UCL tears should help to save money in this field.

Collateral Ligaments↗
PubMed1997

MR and CT anatomy of the axilla.

PURPOSE: To depict the complex anatomy of the axilla with CT and MR imaging. MATERIAL AND METHODS: The axillary regions of 2 cadavers (with arms hyperabducted) were examined by means of CT and MR. In this position the cadavers were frozen and cryosectioned. The anatomical sections documented by the MR and CT images were compared and anatomical structures were designated. To show the reproducibility of the anatomical structures and to find variations, 20 volunteers were also examined by MR, and 20 consecutive patients without axillary symptoms were examined by CT. RESULTS: The complexity of the axilla was excellently shown by both CT and MR, but MR was able to demonstrate more detail in the small vessels and in the brachial plexus. The comparability of the examinations of the different individuals was best in the axial plane. Some differences appeared in the coronal and sagittal planes caused by different positions of the arm. CONCLUSION: Axillary anatomy was demonstrated in detail and was reproducible with CT and MR imaging.

Adult↗
PubMed1996

MR-myelography: a comparison with conventional myelography.

After creating a MR pulse sequence, called MR-myelography, the purpose of the study was to evaluate the value of this sequence in comparison to conventional myelography. Twenty consecutive patients were examined with conventional and MR-myelography concerning the clinical questions of chronic lumbago, spinal canal stenosis, herniated disc, spondylolisthesis and instability. Six observers assessed both examinations independently for subjective criteria such as pictorial quality, depiction of the dural sac, the nerve roots and their sheaths, artifacts, and the usefulness of single MR-myelography slices. Furthermore the number and extent of stenoses had to be judged as an objective criteria. The employed MR-myelography technique is not able to concur with the quality of conventional myelography. A high-grade stenosis is usually overestimated and low grade stenosis underestimated by MR-myelography. But it is easier to depict further relevant stenoses in a preexisting high grade stenotic spinal canal with MR-myelography. Artifacts of the introduced MR-technique do not disturb pictorial and diagnostic quality very much. In conclusion MR-myelography cannot replace conventional myelography. But together with conventional MR-sequences, MR-myelography can be helpful in the assessment of spinal canal stenosis.

Adult↗
PubMed1996

Poland's syndrome and vascular malformations.

Unilateral hypoplasia of the breast and the pectoralis muscle with a missing anterior axillary fold as part of Poland's syndrome are of major concern, especially for women. The latissimus dorsi is one of the most suitable flaps for breast and anterior thorax reconstructions but it may be hypoplastic or absent. If so, a free tissue transfer of the contralateral latissimus dorsi muscle is the next possible option for reconstruction. As Poland's syndrome is additionally associated with vascular malformations of the diseased hemithorax such as hypoplastic or missing vessels, a preoperative angiography is mandatory for planned microvascular tissue transfer.

Abnormalities, Multiple↗
PubMed1996

[Preoperative axillary ultrasound in breast carcinoma: value of the method in routine clinical practice].

AIM: To evaluate the significance of routinely performed preoperative axillary sonography in breast cancer patients. METHOD: 191 patients with surgical treated breast cancer were analysed retrospectively. 74 patients of these had an axillary sonography done by 5 different examiners. RESULTS: For detecting lymph node metastases sensitivity was 68.2% in all T-stages and 50% in T1-stages with a specificity of 100%. Classification of the axillary status (positive or negative for lymph node metastases) is possible in 90.5% for all T-stages and 94.9% for T1-stages. Microscopic and small lymph node metastases are missed by ultrasound. Compared to axillary palpation, sonography is better. CONCLUSION: Preoperative axillary sonography is an useful diagnostic method even when done routinely. If further criteria are considered, axillary dissection could be avoided in some patients.

Adult↗
PubMed1996

[Value of preoperative axilla ultrasound in breast carcinoma].

Preoperative axillary sonography is a superior method in predicting axillary lymph node status than clinical examination in patients with breast cancer. However, the results depend on the skills and care of the examiner, metastases less than 3-5 mm are hardly visible.

Axilla↗