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Biomedical subjects

C Stroszczynski

Publications and source records attributed to C Stroszczynski.

At least 55 records · Page 3Linked to original sources
PubMed2000

MRI and CT in the differential diagnosis of pleural disease.

STUDY OBJECTIVE: To explore the role of MRI in the differential diagnosis of pleural disease. PATIENTS: Forty-two patients with pleural disease were included. METHOD: Retrospective study. All patients were examined with both CT and MRI. The morphologic features of pleural lesions and magnetic resonance signal intensity on T1-weighted, T2-weighted, and contrast-enhanced T1-weighted images were evaluated. RESULTS: Mediastinal pleural involvement, circumferential pleural thickening, nodularity, irregularity of pleural contour, and infiltration of the chest wall and/or diaphragm were most suggestive of a malignant cause both on CT and MRI. Pleural calcification on CT was suggestive of a benign cause. Contrary to what has been previously reported in the literature, neither on CT nor on MRI, pleural thickness >1 cm revealed significant difference between malignant and benign pleural disease (p>0.05, chi(2) test). High signal intensity in relation to intercostal muscles on T2-weighted and/or contrast-enhanced T1-weighted images was significantly suggestive for a malignant disease. Using morphologic features in combination with the signal intensity features, MRI had a sensitivity of 100% and a specificity of 93% in the detection of pleural malignancy. CONCLUSION: When signal intensity and morphologic features are assessed, MRI is more useful and therefore superior to CT in differentiation of malignant from benign pleural disease.

Adult↗
PubMed1999

High-resolution conjunctival contrast-enhanced MRI dacryocystography.

We assessed high-resolution MRI of the lacrimal system with conjunctival contrast enhancement in patients with suspected stenosis. We studied 18 patients with epiphora affecting 22 eyes, using a surface coil, before and after conjunctival and intravenous Gd-DTPA. Stenosis or obstruction of the ducts was found in 18 of 22 cases: at canalicular level in 3 cases, at the sac in 7 cases, and in the nasolacrimal duct in 8 cases. Periductal pathology following surgery to the maxillary sinus or dacryocystorhinostomy was seen in three cases. In conjunction with the findings on syringing and/or conventional dacryocystography, the narrowing was classified as stenosis or obstruction.

Adult↗
PubMed1999

[Malignant lymphoma: magnetic resonance tomography findings in residual supradiaphragmatic space-occupying lesions].

PURPOSE: Evaluation of MR imaging in patients with Hodgkin's lymphoma and high grade non-Hodgkin's-lymphoma and mediastinal residual mass after first line chemotherapy. MATERIALS AND METHODS: MR imaging (1.5 T) was performed in 36 patients (Hodgkin's lymphoma n = 26, NHL n = 10) after first line chemotherapy). Twenty patients had inactive residual mass, 16 patients had residual lymphoproliferative lesions. T1- and T2-weighted spin echo images were visually analysed by a score index (range 1-5) as well as quantification of enhancement by signal-intensity-ratios SImax/SIplain). RESULTS: For the differentiation between residual lymphoproliferative activity and inactive residual mass, the highest accuracy was obtained for the signal intensity of residual mass on T2-w-SE compared to pectoralis muscle (94% sensitivity, 80% specificity, likelihood ratios: 4.0 [LR+]; 0.3 [LR-]). The cut-off value of the SI ratio was calculated retrospectively at 1.96 (p > 0.05). CONCLUSIONS: Differentiation between inactive (fibrotic) and lymphoproliferative (active) residual mediastinal mass is possible by MR imaging using as parameter the size reduction after therapy and the signal intensity on T2-w-SE in comparison to pectoralis muscle. Thus study suggests an additional value using the SI ratio for the differentiation.

Adult↗
PubMed1999

[Fat-saturated, contrast-enhanced spin-echo sequences in the magnetic resonance tomographic diagnosis of peritoneal carcinosis].

PURPOSE: To evaluate contrast-enhanced, fat-saturated spin echo sequences for the detection of peritoneal carcinosis with MRI. MATERIALS AND METHODS: 61 patients, 35 with and 26 without peritoneal carcinosis, were examined with abdominal MRI. Fat-saturated, T1-weighted spin echo sequences were performed before and after administration of Gd-DTPA. In addition, 22 patients with peritoneal carcinosis were examined with contrast-enhanced abdominal CT. RESULTS: 32 of 35 patients with peritoneal carcinosis demonstrated contrast enhancement of the visceral and 30 of 35 enhancement of the parietal peritoneum (91 and 86%, respectively). Wall thickening of the intestine or parietal peritoneum were noted in 21 and 20 of 35 patients (60 and 57%, respectively), ascites in 18 of 35 patients (51%). False positive contrast enhancement of the peritoneum was noted in 4 of 26 patients (15%). In the direct comparison of MRI and CT, 22 of 22 patients versus 7 of 22 patients showed contrast enhancement of the visceral peritoneum (100 and 32%, respectively). For other signs of peritoneal carcinosis (e.g., ascites, peritoneal seedings), no differences in diagnostic reliability were demonstrated. CONCLUSIONS: The use of fat-saturated, spin echo sequences facilitates the diagnosis of peritoneal carcinosis by artifact reduction and improved detection of peritoneal contrast enhancement. MRI with fat-saturated sequences was superior to CT.

Adult↗
PubMed1999

[Retroperitoneal recurrence of non-seminomatous testicular tumors: computerized tomography findings before retroperitoneal lymph node excision].

PURPOSE: In relapsing testicular cancer, additional chemotherapy is followed by abdominal CT. If residual lesions are found, retroperitoneal lymphadenectomy is considered. We studied retrospectively whether morphological criteria can help in selected cases in deciding about lymphadenectomy by distinguishing between vital tumor, scarring and mature teratoma. METHODS: In 26 patients who had been treated by salvage chemotherapy and retroperitoneal lymphadenectomy for non-seminomatous testicular cancer between 1990 and 1997, abdominal computed tomography and histology were correlated. RESULTS: Histological examination found scarring in 10 patients, vital tumor in 6, mature teratoma in 4, and simultaneous teratoma and vital tumor in 6. A single CT criterion for distinguishing between these histologies was not identified. In two patients with large masses which were partly cystic and partly solid vital tumor and teratoma were verified. Scarrings may be expected in cystic lesions at the level of the renal hilus which are lined by a thin and smooth wall. Size did not matter. CONCLUSION: Accurate differentiation between vital tumor and necrosis was not possible. Before lymphadenectomy CT, however, localised lesions.

Adolescent↗
PubMed1999

Uveal melanoma: correlation of histopathologic and radiologic findings by using thin-section MR imaging with a surface coil.

PURPOSE: To evaluate whether the different signal intensities at magnetic resonance (MR) imaging of melanoma are associated with a higher content of melanin. MATERIALS AND METHODS: In a prospective study, MR imaging and ophthalmoscopic examination findings in 42 patients (19 women, 23 men; age range, 30-87 years) with uveal melanoma were compared with histopathologic examination findings obtained after enucleation. MR imaging was performed with 2-mm sections by using a 5-cm surface coil. T1- and T2-weighted images were obtained before and after contrast material administration. RESULTS: In 33 (79%) of the patients, there was homogeneous tumor pigmentation, whereas in nine (21%) patients, there was inhomogeneous bipartite tumor pigmentation. Compared with the histopathologic data, the results of qualitative evaluation were accurate in 29 (58%) of 50 and in 26 (53%) of 49 tumorous areas on T1- and T2-weighted images, respectively. Quantitative evaluation yielded better results, especially at T1-weighted imaging; an 86% correlation was found. Because of methodological reasons, only the superficial pigmentation of inhomogeneous tumors could be evaluated with ophthalmoscopy. CONCLUSION: Thin-section MR imaging of the eye enables an accurate prediction of melanomatous pigmentation with quantitative evaluation of plain T1-weighted images and is superior to ophthalmoscopy in cases of inhomogeneous pigmentation.

Adult↗
PubMed1999

Staging and monitoring of malignant lymphoma of the bone: comparison of 67Ga scintigraphy and MRI.

UNLABELLED: The aim of this study was two-fold: to compare 67Ga scintigraphy with MRI (a) for the staging of malignant lymphoma of the bone and (b) with regard to accuracy in detecting residual disease after first-line chemotherapy for restaging. METHODS: Twenty-one patients with 36 malignant osseous lesions were examined, including 7 patients with primary or multifocal osseous lymphoma and 14 patients with malignant lymphoma and simultaneous or secondary involvement of the bone. After first-line therapy, MRI and 67Ga scintigraphy were performed on 13 patients. The remission status based on all clinical and radiological findings during the follow-up was used as the gold standard. RESULTS: The osseous lesions were located on the axial skeleton in 64% of patients and on the appendicular skeleton in 36%. 67Ga scintigraphy detected 77% of the osseous lesions examined by MRI. For restaging after first-line therapy, MRI had a sensitivity of 90% and a specificity of 80% when dynamic MRI information was included. There were several false-positive results as a result of the pathologic increase in signal intensity ratios of reactive hematopoietic regions after chemotherapy. For 67Ga scintigraphy, a sensitivity of 70% and a specificity of 93% were calculated. CONCLUSION: These data show that monitoring malignant lymphoma of the bone still presents diagnostic problems. Given the high sensitivity of MRI and the high specificity of 67Ga scintigraphy but the limited specificity of MRI and sensitivity of 67Ga scintigraphy, both methods are valuable but should be used as complementary diagnostic tools.

Adolescent↗
PubMed1998

[2D and 3D parameter images for the analysis of contrast medium distribution in dynamic CT and MRI].

AIM: For dynamic contrast medium (CM) studies, parameter images exploit specific features of the time/intensity curve (TIC) of each pixel and represent these values in a new image. Existing concepts of two-dimensional CM analysis are extended for three-dimensional applications using adequate computer graphic visualization. METHODS: Imaging: intravenous CM injection; first-pass analysis using fast CT acquisition of a single slice; CM accumulation by 40 MR slices (6 sequences every 90 s = 240 images): Software: TIC of arbitrary 2D/3D regions; parameter images: (1) temporal maximum intensity projection (TMIP) of all voxels over time, (2) temporal CM gradients (TG) based on TIC amplitude, (3) TIC slope, (4) time of TIC peak, (5) correlation coefficient to reference TIC. The calculated 3D data of CM accumulation was visualized using multiplanar reformation, MIP, surface reconstruction, volume rendering, texture mapping and animation. RESULTS: In first-pass analyses, TMIP and TG allowed the simultaneous or separated presentation of different temporal phases of the CM bolus. Correlation images emphasized regions with similarities to given TIC patterns. Three-dimensional computer graphic techniques enabled (1) anatomical/functional mapping of original image and CM accumulation and (2) fused display of both spatial CM enhancement and color-encoded time of TIC peak in one common image. CONCLUSIONS: The quantification of presence, magnitude, and time-of-peak of CM accumulation in local image regions supports the assessment of vascularization and of ischemic or necrotic areas.

Breast Neoplasms↗
PubMed1998

[Comparative findings of digital thoracic images and digital images of statistical phantoms as film copy, a radiological work station and a PC].

INTRODUCTION: An ROC analysis was carried out in order to determine the reliability of digital luminescence radiography review at a PC and this was compared with a radiological work station and with X-ray film on a viewing box. MATERIAL AND METHOD: 54 chest images obtained by digital luminescence radiography were selected, 31 of these contained small pulmonary nodules. In order to evaluate critical detail, five images of a phantom showing round foci were used. Five radiologists examined these, using a Siemens Magic View work station, a PC with proprietary software (ViewMed) and X-ray films on a viewing box. Image processing of the work station used the standard clinical application. ViewMed performs linear scaling of grey levels to 8 Bit. The results were examined statistically by means of a t-test. RESULTS: As far as the chest images were concerned there was no significant difference in the diagnostic value of these methods. There was, however, a highly significant loss of diagnostic information with respect to the round focus phantom when using the PC compared with the other methods. CONCLUSION: In the configuration in which it was used, the PC should not be relied on as a primary means of examination since critical details cannot always be seen. In routine use these play a subordinate role and there was no significant diagnostic loss where the chest images were concerned. We expect that by improvements in the frequency and contrast processing the PC accuracy will be considerably increased.

Humans↗
PubMed1998

Wavelet versus JPEG (Joint Photographic Expert Group) and fractal compression. Impact on the detection of low-contrast details in computed radiographs.

RATIONALE AND OBJECTIVES: The aim of this study was to evaluate different lossy image compression algorithms in direct comparison. METHODS: Computed radiographs were reviewed after compression with Wavelet, Fractal, and Joint Photographic Expert Group (JPEG) algorithms. For receiver operating characteristic (ROC) analysis, 54 thoracic computed radiographs (31 showing pulmonary nodules) were compressed with a ratio of 1:60. Five images of a test-phantom were coded at 1:13. All images were reviewed on a PC. Uncompressed images were reviewed at a PC and at a radiologic workstation (with image processing). RESULTS: For thorax images, decrease of diagnostic accuracy was significant with Wavelets. Fractal performed worse than Wavelets. No ROC curve was observed for JPEG due to poor image quality. No diagnostic loss was noted comparing PC and Workstation review. For low-contrast details of the phantom, results of Wavelet compression were equal to uncompressed images. Fewer true positives and increased true negatives were noted with Wavelets though. Wavelets were superior to JPEG, and JPEG images were superior to Fractal. Workstation review was superior to PC review. CONCLUSIONS: Only Wavelets provided accurate review of low-contrast details at a compression of 1:13. Frequency filtering of Wavelets affects contrast even at a low compression ratio. JPEG performed better than Fractal at low and worse at high compression ratio.

Algorithms↗
PubMed1998

Choroidal hemangioma: MR findings and differentiation from uveal melanoma.

BACKGROUND AND PURPOSE: The aim of this study was to establish the MR imaging characteristics of choroidal hemangioma and to compare them with those of uveal melanoma. METHODS: Among 41 patients examined at 1.5 T (4-cm surface coil, T1-weighted and fast spin-echo T2-weighted sequences), 25 had uveal melanoma and 16 had circumscribed choroidal hemangioma. After i.v. bolus injection of gadopentetate dimeglumine, dynamic and T1-weighted sequences were acquired. RESULTS: In patients with choroidal hemangioma, uniform signal characteristics were detected on fast T2-weighted images. In 15 of 16 patients with choroidal hemangioma, lesions were isointense with vitreous on fast spin-echo T2-weighted images, whereas lesions in 24 of 25 patients with uveal melanoma were hypointense. Signal characteristics of uveal melanoma and hemangioma did not differ significantly on plain T1-weighted images. Enhancement was earlier and much stronger for circumscribed choroidal hemangioma than for uveal melanoma. After i.v. bolus application of gadopentetate dimeglumine, the increase of signal intensity was higher for circumscribed choroidal hemangioma (signal intensity ratio, 5.8) than for uveal melanoma (signal intensity ratio, 2.2). CONCLUSION: Circumscribed choroidal hemangioma may be difficult to differentiate from melanoma by ophthalmologic examination. Differentiation may not be possible if direct viewing of uveal space-occupying lesions is hampered by opaque vitreous media. The characteristic findings on fast spin-echo T2-weighted MR images and early enhanced images aid in differentiating choroidal hemangioma from uveal melanoma.

Adolescent↗
PubMed1997

[How certain is teleradiological telediagnosis for the tomographic procedure?].

PURPOSE: To define the value of teleradiographic studies, a comparison was carried out between digitised copies of CT examinations of the skull with the original images. Differences in image quality obtained from a digital scanner and a camera were quantified. MATERIAL AND METHOD: 56 CT examinations of the skull, 28 of which had discrete abnormalities, were chosen for ROC analysis. The original films were digitised with a Vidar VXR-12 scanner and Panasonic WV-160 and WV-BP 500 cameras. The images were evaluated by five radiologists after image transfer with Video Conference software to a personal computer. RESULTS: For the analysis of the films the area under the ROC curve was 0.91 +/- 0.04, for the digital scanner it was 0.85 +/- 0.04, for camera WV-BP 500 0.89 +/- 0.06 and for camera WE-160 0.87 +/- 0.09. Comparison with the film findings showed. a minimal p-value of 0.17 which indicated that there was no significant reduction in diagnostic value following digitization. CONCLUSION: The probable reason for the slight deterioration using the digital scanner was the reduction to 75 dpi compared with 134 dpi on the CT films. The cameras produce image noise comparable to CT with low window settings and reduced local resolution. We expect similar results for CT with soft tissue windows or for MRT of the skull. Conventional radiographs containing high local resolution, wide grey scale and low image noise would presumably make higher demands on methods of digitization.

Computers↗
PubMed1997

[Dynamic computerized tomography of the bone marrow of normal and pathologic vertebrae].

PURPOSE: The contrast medium dynamics of normal and abnormal bone marrow was examined by CT. MATERIAL AND METHOD: Standardised sections of lumbar vertebrae were obtained after intravenous injection of 80 ml Ultravist 370 and time-density curves of the marrow spaces were calculated in 38 patients. RESULTS: Time-density curves of patients with normal bone marrow differed significantly from those with proliferative bone marrow diseases in respect of maximal density and uptake at 120 and 240 seconds. Patients treated by radiation showed reduced uptake. CONCLUSION: Variations in the time-density curves between normal and abnormal bone marrow provided evidence of different perfusion and uptake of the contrast medium in the extracellular space of the bone marrow. Further investigation will be necessary to determine whether dynamic CT is able to document the effect of radiotherapy or chemotherapy on malignant bone marrow infiltration.

Adenocarcinoma↗
PubMed1997

[Use of Ga-67 SPECT in patients with malignant lymphoma after primary chemotherapy for further treatment planning: comparison with spiral CT].

PURPOSE: To compare the diagnostic value of gallium scintigraphy using a SPECT technique with spiral CT for evaluating activity following chemotherapy in patients with malignant lymphoma and to determine treatment options. MATERIAL AND METHOD: The results of gallium scintigraphy in 28 patients with malignant lymphoma (19 Hodgkin's disease, 9 high grade non-Hodgkin's lymphoma) following curative treatment were compared with the CT morphology in relation to inactive regions and residual masses. RESULTS: Ga-67-SPECT proved superior to CT for evaluating the activity in 85 initially involved nodes (sensitivity 94.4% against 83.3%; specificity 100% against 92.5%). It was, however, inferior for demonstrating organ involvement in 28 instances. In seven patients with residual masses, Ga-67-SPECT directly affected staging and further therapy. CONCLUSION: The increasing use of secondary treatment schemes for curative purposes makes Ga-67-SPECT a suitable method for the early recognition of residual activity in Hodgkin's disease and high grade non-Hodgkin's lymphoma.

Adult↗
PubMed1996

[clinical application of multiplanar and 3D reconstruction of spiral CT in diagnosis of acetabulum fractures].

This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of each method are demonstrated and the diagnostic potential of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed.

Acetabulum↗