PubMed Health⌕ Search

Biomedical subjects

R Groell

Publications and source records attributed to R Groell.

At least 19 recordsLinked to original sources
PubMed2002

Detection of the sinus node artery using electron beam computed tomography of the heart.

BACKGROUND: Stenosis or obstruction of the sinus node artery (SNA) of the heart can cause cardiac arrhythmia and even sudden death. The purpose of this study was to evaluate the detectability of the SNA using electron beam computed tomography (EBCT). MATERIAL AND METHODS: Eighty patients (mean age: 61 +/- 10 years, range: 31-80 years) were examined with ECG-triggered EBCT (exposure time: 100 ms, slice thickness: 1.5 mm), using two different detector systems (n = 40; 9.5 line pairs/cm [Lp/cm]; n = 40; 7 Lp/ cm) after intravenous contrast agent administration. Twenty-four out of 80 (30%) patients had supraventricular arrhythmia. RESULT: The SNA was detected in 60/80 (75%) of all patients with an average length of 16 +/- 7 mm (3-35.2 mm). One additional branch of the SNA was detectable in 17/80 patients (21%), two branches in 6/80 (8%). There was no significant difference between the two used detector systems (p < 0.01) or between patients with or without supraventricular arrhythmia (71 vs. 77%; p = ns). CONCLUSION: EBCT allows to detect small coronary arteries such as the SNA of the heart.

Adult↗
PubMed2002

Combination of surgery and gamma knife radiosurgery--a therapeutic option for patients with tumors of nasal cavity or paranasal sinuses infiltrating the skull base.

UNLABELLED: The purpose of this study was to investigate whether patients operated for skull base-infiltrating malignant tumors of the nasal cavity and/or the paranasal sinuses benefit from an additional Gamma knife radiosurgery. CASE SERIES: eight consecutive patients, (male: female ratio = 1:1, mean age = 52 years, range 34 to 79 years) presented with 2 cyclindric cell carcinomas, 2 adenocarcinomas, 2 malignant neuroblastomas, 1 squamous cell carcinoma, 1 amelanotic melanoma. Tumor stages (UICC) were: 1 T1, 3 T2, 3 T3, 1 T4, all N0, all M0. All patients were primarily treated surgically and 4 weeks later received additional stereotactic radiosurgery. Follow-up was based on computerized tomography (CT), magnetic resonance imaging (MRI), endoscopy, and biopsy. The course of disease was compared to tumor courses with surgery but without radiosurgery reported in literature. Four times endoscopic endonasal surgery (EES), once EES in combination with fluorescein technique, once EES plus external approach of frontal sinus, once lateral rhinotomy was performed. All 8 cases underwent radiosurgery (Leksell gamma knife) 4 weeks after surgery. Thirty six months after radiosurgery 6 patients were alive (4 patients without evidence of disease, 1 patient with pulmonary metastasis but without local recurrence, 1 patient with regional metastasis but no local recurrence), 1 patient died 11 months after treatment due to disease, 1 patient died due to a second malignancy. No negative or adverse effects due to radiosurgery were observed. The combination of microsurgery with Leksell Gamma knife radiosurgery appears to be an encouraging therapeutic option. To date no adverse effects have been observed in the presented cases.

Adult↗
PubMed2001

Peripheral primitive neuroectodermal tumour of the kidney: CT findings.

Peripheral primitive neuroectodermal tumour in the kidney is a rare entity with high malignant potential. The distinctive demographic, clinical and radiological findings, as described in the present case, should suggest this aggressive tumour in the differential diagnosis of renal neoplasms in adolescents.

Adolescent↗
PubMed2001

Contrast-enhanced helical CT of the head and neck: improved conspicuity of squamous cell carcinoma on delayed scans.

OBJECTIVE: We evaluated the impact of delayed scans on the conspicuity of squamous cell carcinoma in helical CT of the head and neck. SUBJECTS AND METHODS: Twenty-seven patients with biopsy-proven squamous cell carcinoma of the head and neck underwent dual-phase helical CT examinations using 100 mL of nonionic contrast material. In all patients, the early phase started 30 sec after the commencement of injection. The patients were assigned to one of two groups in which the delayed phase started either 180 sec (group A, n = 13) or 300 sec (group B, n = 14) after the start of injection. The overall image quality, including vascular opacification and the quality of lesion conspicuity, was determined according to a three-point scoring system. RESULTS: Overall image quality scored better on the early scans (score, 1.4 +/- 0.5) than on the late scans with a 180-sec (score, 1.6 +/- 0.6; p = 0.03) or a 300-sec delay (score, 2.4 +/- 0.5; p = 0.002). Tumor conspicuity scored better on scans with a 180-sec delay (score, 1.4 +/- 0.5) than on the scans with a 30-sec delay (score, 2.3 +/- 0.7; p = 0.02) or the scans with a 300-sec delay (score, 2.3 +/- 0.7; p = 0.03). In eight (62%) of 13 patients in group A and in six (43%) of 14 patients in group B, the tumor was better delineated on the late scans than on the early scans. CONCLUSION: Although early scans provide optimal vascular enhancement and are therefore necessary for helical CT studies of the head and neck, additional delayed scans may improve lesion detection in patients with squamous cell carcinoma of the head and neck.

Carcinoma, Squamous Cell↗
PubMed2000

Radiotherapy as adjunct to surgery for malignant carotid body paragangliomas presenting with lymph node metastases.

PURPOSE: Three cases of malignant carotid body paragangliomas with nodal metastases are reported. PATIENTS AND METHODS: Between 1985 and 1994, 3 female patients (51 to 65 years of age) were referred for postoperative radiotherapy after complete (2) or incomplete (1) surgical excision of a malignant carotid paraganglioma (Shamblin III). Preoperative angiographic embolization of the tumor-supplying arteries was performed in all cases. In 2 patients resection of the internal carotid artery and reconstruction by saphenous vein graft was necessary. Continuous course radiotherapy of the tumor bed (50 to 56 Gy/2 Gy) and regional lymph nodes (50 Gy) using photon beams was delivered in 2 patients. The third patient having had incomplete resection cancelled radiotherapy after 4 Gy. RESULTS: Within an observation time of 110 and 119 months no evidence of recurrence was obtained in both patients irradiated postoperatively. The third patient died of progressive disease. Twelve months after the withdrawn irradiation she presented with a tumor progression into the brain and an ulcerated mass on the right side of the neck and was irradiated consecutively for palliation (Figures 1a to 1f). In none of the patients severe acute or late radiation-induced complications were observed. CONCLUSION: In patients with malignant paraganglioma moderate dose postoperative radiotherapy of the tumor bed and regional lymph nodes is well tolerated. It seems to be effective to prolong local control after surgery, to eradicate microscopic lymphatic disease and eventually to postpone further spreading.

Aged↗
PubMed2000

Imaging the coronary venous drainage system using electron-beam CT.

This study describes the appearance of the coronary sinus and its tributary veins as visualized on ECG-triggered electron-beam computed tomography (CT) and investigates their spatial relationship to other cardiac structures. Thirty-two patients were examined with ECG-triggered electron-beam CT (exposure time: 100 ms, slice thickness: 1.5 mm) after intravenous contrast agent administration. The entire heart was imaged; the appearance of the coronary sinus and its tributary veins were evaluated. In all 32 patients the anterior interventricular vein and the posterior interventricular vein drained into the coronary sinus. The small cardiac vein was visualized in five patients, a posterior vein of the left ventricle in three and the left marginal vein in eleven. The coronary sinus of all 32 patients had a average length of 30 mm +/- 10 mm (mean +/- SD), range: 21-40 mm and a diameter of 9 mm +/- 5 mm (mean +/- SD), range: 4-14 mm. The results of our work show that if the entire heart volume is scanned using ECG-triggered electron-beam CT, the delineation and the differentiation of the major cardiac veins is possible on transverse cross sections in a way which corresponds to the anatomical literature. Hence to the similar enhancement and similar diameter of coronary veins and arteries on contrast-enhanced electron-beam CT studies, the radiologist should be familiar with the cross-sectional anatomy of the major cardiac veins to prevent possible misinterpretation.

Adult↗
PubMed2000

[Current status of diagnostic imaging of focal nodular hyperplasia of the liver].

Ranging behind hemangiomas, focal nodular hyperplasias (FNH) are the second most common benign solid liver lesions. Women between the age of 20 and 50 years are predominantly affected. In rare cases FNH may occur in children. Etiologically, an arteriovenous vascular malformation of the liver is discussed, which causes pseudotumorous growth of the surrounding liver parenchyma. Morphological features such as the presence of a radial vascular architecture and feeding arteries within a central scar are characteristic for the presence of FNH. Imaging techniques which enable the depiction of the arterial blood supply with a characteristic centrifugal filling pattern, the contrast enhancement in the early arterial phase, the absence of calcifications and of a tumour capsule and the typical enhancement of the central scar, are of particular importance. Knowledge of these features is important in order to differentiate FNH from other hypervascular focal liver lesions with tendency of scar formation, such as hepatic adenomas, giant hemangiomas, hepatocellular and fibrolamellar carcinomas, and metastases. Diagnosis and differential diagnosis of FNH will be enabled by a combined modality approach consisting of (Doppler) sonography and triphasic CT. To confirm the diagnosis of FNH, dynamic MRI is advisable. Because of the invasiveness of angiography as well as the limited sensitivity and spatial resolution of the various scintigraphic methods, these modalities no longer play a role in the diagnostic work-up of FNH. Lesions lacking typical features diagnostic for FNH remain subjects for biopsy and histological examination.

Adult↗
PubMed2000

Noninvasive measurement of pulmonary vascular resistances by assessment of cardiac output and pulmonary transit time.

RATIONALE AND OBJECTIVES: Pulmonary vascular resistance is of special interest in many diseases. Usually it is determined invasively by catheterization, but cardiac output and pulmonary transit time can be ascertained by several noninvasive methods. METHODS: Fourteen heart recipients (age 34-71 years) were examined by electron-beam CT of the heart. Cine and flow studies were performed using a total of 60 mL of contrast and a breath-hold of 20 seconds. RESULTS: A mathematical model for calculating pulmonary vascular resistances from noninvasively measured cardiac outputs and pulmonary transit times was developed. Right-sided heart catheterization served as the reference method. CONCLUSIONS: The formula created seems to allow a clinically valid estimate of pulmonary vascular resistance from noninvasively acquired data.

Algorithms↗
PubMed2000

Helical CT angiography with maximum intensity projection in the assessment of aortic coarctation after surgery.

OBJECTIVE: The value of CT angiography and three-dimensional (3D) reconstructions was investigated in the postoperative care after surgical repair of aortic coarctation and compared with conventional angiography. SUBJECTS AND METHODS: Twenty-five patients referred because of suspicion of stenosis in the area of former coarctation were prospectively studied with CT angiography and catheter angiography. We determined the morphometric and morphologic findings such as aortic diameter, stenosis, aneurysm, intimal flaps, circumscribed pouch, or arteriosclerotic plaques with 3D reconstructions, using maximum-intensity-projection (MIP) technique and catheter angiography. The results of both techniques were compared. The ratio of the narrowest diameters of the former coarctation and the descending aorta was correlated with the systolic pullback blood pressure gradient in all patients. RESULTS: The former coarctation was normal in 11 patients, (44%), group A; narrowed in 12 children (48%), group B; and dilated in two children (8%), group C. An intimal flap and a circumscribed pouch were delineated in four subjects. MIP reconstructions and catheter angiography revealed identical results regarding the classification into groups A, B, C; intimal flaps; and circumscribed pouches. Statistical analysis revealed good correlation between the narrowest aortic diameters measured on MIP reconstructions and catheter angiography, whereas no correlation between the systolic pullback blood pressure gradient and the diameter ratio of the former coarctation and the descending aorta was found. CONCLUSION: CT angiography and 3D reconstructions using MIP represent a reliable noninvasive technique to replace diagnostic catheter angiography in the postoperative care of patients with coarctation and provide the clinician with valuable information concerning further invasive procedures.

Adolescent↗
PubMed1999

Radiotherapy for invasive thymoma and thymic carcinoma. Clinicopathological review.

PURPOSE: This study reports clinicopathological features and outcome of thymic tumors. Twenty-seven patients with invasive thymoma and 6 patients with thymic carcinoma who had received radiotherapy either primary or postoperatively were analyzed retrospectively. PATIENTS AND METHODS: All 33 patients were irradiated with a mean dose of 50 Gy after complete resection (16 patients), partial resection (9 patients) or biopsy (8 patients). Staging was done according to the Masaoka classification; there were 12 Stage II, 12 Stage III and 9 Stage IV patients. RESULTS: In patients with invasive thymoma Stage II to IV (median follow-up 54.4 months) Kaplan-Meier estimates of overall survival (OS), disease-specific (DSS) and disease-free survival (DFS) at 5 years were 63.7% (95% confidence interval [CI], 42 to 84%), 88.3% (CI, 75 to 100%) and 77.4% (CI, 58 to 95%), respectively. Among the prognostic factors tested, such as age, myasthenia gravis, completeness of surgery and histologic subclassification, total radiation dose, and Masaoka Stage, the latter was the only significant predictor of improved survival (p = 0.04). Considering local control, radiation dose was a significant prognostic factor (p = 0.0006). In patients with thymic carcinoma (median follow-up 43.4 months) 5-year DSS, and DFS were 22.2% (CI, 0 to 60%) and 16.7% (CI, 0 to 46%), respectively. Thymoma as compared to thymic carcinoma had a statistically significant better DSS (p = 0.007) and DFS (p = 0.0007). CONCLUSION: Postoperative radiotherapy with sufficient doses plays an important role as adjuvant treatment in complete or incomplete resected invasive Stage II to III thymoma. In unresectable thymoma Stage III to IV as well as in thymic carcinoma a multimodality approach should be considered to improve survival.

Actuarial Analysis↗
PubMed1999

Drop metastases in a patient with a chondroid chordoma of the clivus.

Metastasising chordomas are extremely rare and only four cases with drop metastases have been reported. We report a patient with an intracranial chondroid chordoma, typically involving the clivus, treated by repeated resection, percutaneous transluminal embolisation and radiosurgery. During follow-up with MRI asymptomatic intradural drop metastases were observed throughout the spine, with transgression of the intervertebral foramen, forming a "dumbbell".

Adult↗
PubMed1999

Computed tomography densitometry of the lung: a method to assess perfusion defects in acute pulmonary embolism.

OBJECTIVE: To evaluate the potential of spiral computed tomography (CT) densitometry of the lung to assess segmental perfusion defects in patients with acute pulmonary embolism. MATERIALS AND METHODS: Ten patients with known segmental or lobar perfusion defects on ventilation/perfusion scintigraphy and with normal findings in the contralateral lung segment underwent spiral CT of the thorax before and after the administration of contrast material. Regions of interest were defined in 14 segments with normal perfusion and in 14 segments with reduced perfusion. Three consecutive densitometry measurements were performed in each segment. RESULTS: Those segments with reduced perfusion showed a significantly lower mean CT value on the enhanced scans (-813.4 +/- 57.1 Hounsfield units (HU) vs -794.0 +/- 44.8 HU, P = 0.01) and a significantly decreased contrast enhancement (12.3 +/- 18.2 HU vs 29.8 +/- 16.6 HU, P <0.01) when compared to segments with normal perfusion. Measurements from the unenhanced CT scans were not statistically different between segments with reduced and normal perfusion. CONCLUSIONS: Spiral CT densitometry allows the assessment of at least segmental perfusion defects in patients with acute pulmonary embolism.

Absorptiometry, Photon↗
PubMed1999

The pneumatic spaces of the temporal bone: relationship to the temporomandibular joint.

OBJECTIVES: To assess the topographic relationship between the pneumatic spaces of the temporal bone and the temporomandibular joint (TMJ) using high-resolution CT. METHODS: Findings from 100 consecutive patients who had undergone high-resolution axial CT of the base of the skull were reviewed on a digital imaging workstation. Additional multiplanar reformatted images were created in the sagittal and coronal planes through the TMJ. The extension of the pneumatic spaces of the temporal bone and their relation to the TMJ were determined on both sides. RESULTS: The extent of pneumatisation of the temporal bone varied considerably. The roof of the TMJ fossa was pneumatised in 51 patients. The articular eminence contained air spaces in 12 patients, the root of the zygomatic process in five patients. Air cells in the peritubal area extended into the medial wall of the glenoid fossa 53 patients. In approximately 25% the extent of pneumatisation showed marked asymmetry. CONCLUSIONS: Pneumatisation of the temporal bone frequently extends close to the TMJ. Knowledge of these air spaces is helpful for the interpretation of imaging studies such as panoramic radiographs and to understand the spread of pathological processes into the joint.

Adolescent↗
PubMed1999

Pericardial sinuses and recesses: findings at electrocardiographically triggered electron-beam CT.

PURPOSE: To evaluate the appearance of the pericardial sinuses and recesses at electrocardiographically triggered electron-beam computed tomography (CT). MATERIALS AND METHODS: Findings in 100 patients without known pericardial disease were reviewed. The patients underwent electron-beam CT of the heart because of suspected coronary arterial disease. Incremental electrocardiographically triggered images were obtained with a 100-msec exposure time and 1.5-mm section thickness after intravenous administration of contrast material. The appearance of the pericardial sinuses and recesses was determined. RESULTS: In each patient, at least one of the sinuses was visible at CT. The transverse and oblique sinuses (or one of their recesses) were depicted in 95 and 89 patients, respectively. The left pulmonic recess was depicted in 81 patients; inferior aortic recess, 80 patients; posterior pericardial recess, 67 patients; left pulmonic vein recess, 60 patients; right pulmonic recess, 51 patients; superior aortic recess, 47 patients; right pulmonic vein recess, 29 patients; and postcaval recess, 23 patients. CONCLUSION: Pericardial sinuses and recesses are frequently depicted on electrocardiographically triggered electron-beam CT images. Knowledge of their locations is helpful in the differentiation of normal pericardium from pericardial effusions and mediastinal processes such as lymph nodes.

Adult↗
PubMed1999

The reliability of bone age determination in central European children using the Greulich and Pyle method.

This study assessed the reliability of bone age determination in normal central European children using the Greulich and Pyle method and determined the effects of readers' experience on the measured bone ages. Plain hand radiographs of 47 children (aged 2 months to 18.8 years) with normal growth were analysed by four radiologists (two experienced paediatric radiologists and two radiology residents). The readers were blinded to the age of the children. The images were re-read by the same readers 2 months later. The mean intraobserver and interobserver variations were lower for experienced readers than for radiology residents. However, these differences were not statistically significant at the 5% level. The difference between the chronological age and the measured bone age was -1.5 +/- 7.6 months (p = 0.20) for the experienced readers and 2.7 +/- 10.3 months (p = 0.09) for the radiology residents. The differences between the measured bone age and chronological age were statistically significant (p = 0.04) for only one of the two radiology residents. Although the measurements by all four readers underestimated the chronological age, the differences between chronological age and bone age were within the normal variations of skeletal maturation as reported by Greulich and Pyle. Our data suggest that the reliability of bone age measurements increases with experience and that the Greulich and Pyle method may be used for central European children.

Adolescent↗
PubMed1999

Orbital dirofilariasis: MR findings.

Dirofilariasis is a helminthic zoonosis occurring in many parts of the world. We report the findings in a 61-year-old woman who had painless right exophthalmos caused by orbital dirofilariasis. A vivid worm was embedded inside an inflammatory nodule in the right orbit. On T1-weighted MR images, the parasite was visible as a discrete, low-intensity, tubular signal in the center of the nodule surrounded by contrast-enhancing inflammatory tissue.

Dirofilariasis↗
PubMed1999

Contrast-enhanced spiral CT of the head and neck: comparison of contrast material injection rates.

BACKGROUND AND PURPOSE: Contrast-enhanced spiral CT studies of the head and neck are performed frequently using contrast material volumes of approximately 30 g iodine and a scan delay of 30-45 seconds. Because little is known about the effects of contrast material injection rates on tissue enhancement, this was prospectively investigated in our study. METHODS: Ninety-seven patients underwent spiral CT of the head and neck. Each patient was assigned randomly to one of four groups who received 100 mL of nonionic contrast material (300 mg I/mL) at different monophasic injection flow rates with 1.5, 2, 3, and 4 mL/s. Scanning started after a constant delay of 35 seconds. The attenuation of the carotid artery, jugular vein, and sternocleidomastoid muscle was measured over time and the attenuation of the submandibular and thyroid gland was evaluated. Vascular attenuation of at least 150 HU was considered to be sufficient. RESULTS: The mean scan time was 33+/-5 seconds. The study, using an injection rate of 2 mL/s, showed the longest time of sufficient overall (arterial and venous) vessel attenuation (27+/-4 seconds, P< or =.008). The injection flow rate did not influence significantly muscular attenuation (mean enhancement during scan time: 9+/-7 HU). The 1.5 mL/s protocol showed the lowest attenuation values of the submandibular gland (81+/-12 HU) and the highest attenuation values of the thyroid gland (164+/-22 HU), but the attenuation of the thyroid gland was not statistically different from that revealed by the 2 mL/s protocol. CONCLUSION: Using 100 mL of intravenous contrast material with 300 mg I/mL for spiral CT studies of the entire head and neck, the optimal injection flow is 2 mL/s, whereas lower flow rates resulted in insufficient venous enhancement.

Adult↗