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Biomedical subjects

E Grabbe

Publications and source records attributed to E Grabbe.

At least 109 records · Page 6Linked to original sources
PubMed1997

A comparison of conventional mammographic magnification, ultra high magnification and industrial magnification radiography in the radiographic detection of microcalcifications within core biopsies of the breast.

The objective was to compare conventional magnification radiography (CMR), ultra high magnification radiography (UHMR) and industrial magnification radiography (IMR) in the detection of microcalcifications in breast core biopsies. 440 core biopsies were examined in 1.8-fold CMR and in 7-fold UHMR using a prototype unit. A subgroup of 59 core biopsies were also examined in 10-fold IMR. Number, size, and demarcation of microcalcifications, as well as tissue contrast, were evaluated. Only 67% of the microcalcifications seen with UHMR were detected by CMR and 78% of the core biopsies showing calcifications in UHMR were calcified in CMR. Only 38% and 58% of microcalcifications verified by IMR were identified by CMR and UHMR, respectively. 47% and 63% of the core biopsies showing calcifications in IMR were calcified in CMR and UHMR, respectively. Tissue contrast of IMR was superior to both other modalities. On the other hand, increased cost and time will probably prohibit the use of IMR for specimen radiography in routine clinical examinations. In conclusion, UHMR identifies substantially more core biopsies with microcalcifications than CMR, thus potentially reducing the number of core biopsies needed for histological analysis. IMR allowed the detection of approximately 50%/160% more microcalcifications than UHMR/CMR, thus rendering it the reference mode.

Biopsy↗
PubMed1997

Dual-phase helical CT of the kidney: value of the corticomedullary and nephrographic phase for evaluation of renal lesions and preoperative staging of renal cell carcinoma.

OBJECTIVE: Our objective was to evaluate early-phase unenhanced and late-phase contrast-enhanced helical CT in revealing renal lesions and staging renal cell carcinomas. SUBJECTS AND METHODS: Contrast-enhanced helical CT of the kidneys was performed in 145 patients who also underwent unenhanced CT. Contrast-enhanced CT was performed in the corticomedullary phase (CMP) and nephrographic phase (NP). A total of 173 lesions in 96 patients were proven histologically or cytologically. The performance of helical CT in the three study groups was compared: unenhanced and CMP enhancement, group 1; unenhanced and NP enhancement, group 2; unenhanced, CMP enhancement, and NP enhancement, group 3. Among the parameters evaluated were the sensitivity for helical CT of all 173 renal lesions and the sensitivity and specificity for the 90 malignant tumors. Also, the preoperative CT staging of the 76 renal cell carcinomas was correlated with the pathologic specimens. RESULTS: The sensitivity for detection of all renal lesions in group 1 (84%) was significantly less than in groups 2 and 3 (97% and 100%). The specificity and accuracy of helical CT in revealing renal cell carcinomas were significantly higher (p < .05) in group 3 (95% and 95%, respectively) than in groups 1 (93% and 92%, respectively) and 2 (89% and 91%, respectively). Two renal cell carcinomas were overlooked by the interpreters of the helical scans in group 1. The accuracy of preoperative CT staging of renal cell carcinomas was significantly better (p < .05) in group 3 (91%) than in groups 1 (82%) and 2 (86%). CONCLUSION: When patients underwent unenhanced helical CT, CMP helical CT, and NP helical CT, we achieved a better rate of detection and characterization of renal lesions and better preoperative staging of renal cell carcinomas than when we used either CMP helical CT or NP helical CT alone.

Adult↗
PubMed1997

[MR angiography of the pelvic-leg blood vessels: current status and perspectives].

Currently 2D time-of-flight (TOF) MR angiography (MRA) is most commonly used for the evaluation of the extremities. The major limitation of all MRA techniques is their susceptibility to signal loss from intra-voxel phase dispersion. This leads to an overestimated grading of the stenosis. Further difficulties are motion artifacts and the limited spatial resolution. Therefore, MRA alone cannot be used routinely as a preoperative diagnostic procedure in patients with peripheral arterial disease. The postoperative examination of patients with vascular bypasses, however, seems to be a practical application of this technique. It is also possible to use MRA to image the lower limbs after percutaneous interventional angioplasty. The application of 2D-ECG-triggered sequences or the current fast technique of contrast-enhanced 3D-TOF MRA might play a role in combination with surface coils for future examinations of peripheral arterial disease.

Arterial Occlusive Diseases↗
PubMed1997

[Digital image magnification mammography with the storage-screen technique. Standardized and findings-oriented image processing parameters].

Present day mammography has not been able to make use of the advantages of digital luminescence radiography because of the limited spatial resolution. The recent development of electromagnetic focusing x-ray tube with effective focal spot sizes from 0.04 to 0.12 mm allows radiographic direct magnification with less geometric blur. It is now possible to combine direct magnification mammography with digital luminescence radiography. By combining high quality storage phosphor screens with an HQ-workstation a spatial resolution of 8 lp/mm is possible for 1.7-fold magnification. For 4-fold spot magnification views spatial resolution can be theoretically increased to approx. 20 lp/mm. One important advantage of digital radiography is the possibility of image-post-processing. This article presents two sets of standard parameters and three sets of image dependent parameters for better imaging of specific lesions, such as microcalcifications. The introduction of the the storage phosphor screen technique in mammography is one step in the development of direct digital radiography. Further interesting perspectives for the future include post-processing programs for detecting suspicious lesions which are already being clinical tested.

Breast Neoplasms↗
PubMed1996

[Diagnostic imaging of instability of the shoulder joint].

The diagnosis of glenohumeral instability is based on the patient's history and physical examination. The main objective in using imaging techniques is to define the type and extent of the underlying pathology for therapeutic planning. Plain radiography is the initial step in the diagnostic procedure but can miss typical lesions of the glenohumeral joint structures. CT arthrography and MR imaging offer great sensitivity and accuracy for the detection of traumatic abnormalities of the labral-capsular complex, fractures of the glenoid rim and Hill-Sachs lesions. The advantages and pitfalls of both imaging techniques are discussed.

Chronic Disease↗
PubMed1996

[2-D-time-of-flight MR angiography of the peripheral blood vessels. Experimental and clinical studies on value of this method in arterial occlusive diseases].

PURPOSE: A retrospective study was performed in 70 patients with peripheral vascular disease who underwent MR angiography of the lower extremity. MATERIAL AND METHODS: MR angiography was performed with a 2-D-TOF sequence including a travelling presaturation to suppress the venous signal. Postprocessing images were obtained with the MIP algorithm. The MRA results were compared with conventional or digital angiography in all patients. RESULTS: Only 19 stenoses out of 31 which showed a degree of stenosis between 30 and 99% could be visualised by MR angiography. 9 stenoses were correctly classified by MRA. In 9 cases the degree of stenosis was overestimated, in one case it was underestimated. All 56 occlusions were correctly detected. 12 severe stenoses diagnosed with conventional angiography were graded as occlusions with MR angiography. CONCLUSIONS: MR angiography cannot be accepted in preoperative staging of patients with peripheral vascular disease. The postoperative examination seems to be a practical noninvasive alternative.

Algorithms↗
PubMed1996

[Contrast medium administration in spiral computed tomography: the results of a consensus conference. Institute for Radiodiagnosis, Regensburg].

The rapidity of spiral (helical-) computed tomography requires new protocols for i.v. contrast media administration. Flow rate, volume and delay are discussed controversially in the literature. Hence, a consensus meeting was initiated. In this meeting, problem related questions were designed, discussed and answered using a digital vote system. Spiral-CT-technology was found to be the ideal examination technique for thorax, liver, pancreas, kidney and the retroperitoneal space with an overall agreement between 89 and 97%. The exclusive use of nonionic contrast media and power injectors was recommended by 100% of the participants. More than 90% of the contributors did not accept native scans only for examinations of the neck, thorax, liver, pancreas, kidney and the retroperitoneal space. Regarding volume, flow rate, delay and physical CT-parameters the agreement laid between 50 and 100%. The meeting concluded that randomised controlled studies should be performed to evaluate detailed contrast media protocols for helical CT.

Berlin↗
PubMed1996

[Spiral CT with reduced radiation dosage].

PURPOSE: To examine the clinical use of a reduced dose in high-resolution spiral-CT (HR-SCT) in combination with a multiplanar volume reconstruction technique (MPVR) to decrease image noise. MATERIAL AND METHODS: Facial bones, skull and extremities of 33 patients with different pathological findings were examined with spiral-CT using a slice thickness of 1 mm (pitch 1.7-2.0), a tube amperage of 40 mA and tube voltages of 80 or 120 kV. Additionally, 2-D, 3-D, and MPVR images reconstructions were performed. MPVR takes advantage of displaying planar volumes of variable thickness. RESULTS: Increased image noise was negligible if high contrast structures like bones were examined. However, very small bony structures like the stapes of the middle ear were not seen. Soft tissues could also be imaged by using the MPVR-technique. This technique did reduce image noise while at the same time partial volume averaging was increased. The skin entrance dose per investigation did not exceed 3 mGy, which is based on twelve dose measurements in two patients. CONCLUSION: It is feasible to perform HR-SCT with secondary reconstructions of facial bones, skull and extremities using reduced skin entrance doses by 10 to 20 fold to below 3 mGy. With the exception of imaging very small structures, sufficient image quality can be accomplished in routine examinations without relevant diagnostic compromise.

Arthrography↗
PubMed1996

[Ductal carcinoma in situ in dynamic MR-mammography at 1.5 T].

PURPOSE: To define the value of contrast-enhanced MR mammography in ductal carcinoma in situ (DCIS). MATERIAL AND METHODS: In a group of 35 patients with DCIS, the results of MR imaging were compared to histopathology and immunohistochemistry in a retrospective study. RESULTS: In 35 patients with DCIS, a signal enhancement was found in 25 cases (72%). In 15 of these cases, the signal time curve was typical for malignancy. The other 10 patients had non-specific signal curves. Six of 35 patients (11%) had no enhancement within the tumour region. Four of 35 patients (11%) had bilateral diffuse signal increase, and regions of DCIS could not be identified clearly. Three DCIS were visualised exclusively by MR mammography. The configuration of signal enhancement was sharp (32%), unsharp (48%) or dendritic (20%). DCIS of the comedo type showed a significantly higher enhancement than the non-comedo type. A significant correlation between the grade of vascularisation in immunohistochemistry and signal enhancement in MR mammography could not be demonstrated. CONCLUSION: Dynamic MR mammography does not reliably visualise DCIS.

Adult↗
PubMed1996

[Three-dimensional surface imaging of the larynx and trachea by spiral CT: virtual endoscopy].

A survey presents the technical conditions and facilities of the computed tomographic virtual endoscopy. The inner surface of the upper airway was reconstructed from the data set of a helical CT. The anatomical structures were visualized in over 80 patients. 15 patients with a suspected tracheal stenosis were additional investigated. The virtual endoscopy allowed an identification of the anatomical structures. Pathological endoluminal findings, as stenosis, were investigated successfully. The virtual endoscopy combines the advantages of helical CT and the imaging of the endoluminal surface. Compared with the endoscopic examination the non-invasive technique offers additional indications, especially in high-risk patients or non-passable Stenosis.

Adult↗
PubMed1996

[MRI-controlled intervention in suspected lesions of the breast].

PURPOSE: To evaluate two different systems for magnetic resonance (MR) imaging-guided breast interventions. MATERIALS AND METHODS: 41 patients with 41 lesions detected exclusively with contrast-enhanced MR imaging underwent 68 interventional procedures (27 needle biopsies and 41 preoperative wire localisations) with two different systems. An add-on device for surface coils was used in 39 cases, and a dedicated single breast biopsy coil was used in 29. For needle biopsies, material was aspirated with nonmagnetic 19.5 gauge needles. For preoperative localisations, nonmagnetic wires were used. RESULTS: Surgical excision verified the cytological findings in 23 of the 27 cases sampled for biopsy. Cytological diagnosis was impossible in three cases. One technical failure occurred with the biopsy coil. Open biopsy performed after MR imaging-guided localisation successfully removed 38 of the 41 lesions. One missed carcinoma was found at repeat localisation and removed. Two technical failures occurred with the biopsy coil. In these cases, the lesions were close to the chest wall. CONCLUSIONS: Both systems are suitable for MR-guided fine-needle biopsy and preoperative localisation of breast lesions seen exclusively on MR images.

Biopsy, Needle↗
PubMed1996

Microcalcifications in breast core biopsy specimens: disappearance at radiography after storage in formaldehyde.

PURPOSE: To determine whether radiographically proved calcifications in core biopsy specimens are better preserved in a nonaqueous fixative than in aqueous solutions. MATERIALS AND METHODS: One hundred fifty core biopsy specimens were taken from two female breast specimens that had been preserved in ethanol. Forty-one of the specimens with radiographically proved microcalcifications were divided into four groups and deposited in four different solutions: 10% formaldehyde, 0.9% sodium chloride, electrolyte solution, and 74.1% ethanol with 10% 2-propanol. The core specimens were radiographed again after 1 and 3 days. Five ethanol-preserved specimens were also reexamined radiographically after 2 weeks. RESULTS: Within 3 days, total radiographic disappearance of microcalcifications was observed in all core biopsy specimens that were immersed in solutions with high water content. In those core specimens preserved in ethanol, microcalcifications showed no change. CONCLUSION: A nonaqueous fixative, such as ethanol, is a better preservative of microcalcifications in breast core biopsy specimens than various aqueous solutions, possibly because calcium compounds are water-soluble.

Biopsy↗
PubMed1996

Stereotaxic add-on device for MR-guided biopsy of breast lesions.

Breast biopsy and lesion localization were performed with gadolinium-enhanced magnetic resonance (MR) imaging guidance, with use of a stereotaxic biopsy system consisting of a flexible circular surface coil with an acrylic cylinder as an add-on guidance device. Twenty-five procedures (23 localizations, two core biopsies) were performed in lesions depicted at diagnostic MR imaging, without technical failure. The guidance system permitted easy, precise, and flexible biopsy and localization of all breast lesions.

Biopsy, Needle↗
PubMed1996

Dual-phase helical CT of the liver: effects of bolus tracking and different volumes of contrast material.

PURPOSE: To evaluate the effects of tracking and volume of contrast material on dual-phase helical computed tomography (CT) of the liver. MATERIALS AND METHODS: CT was performed in 120 consecutive patients. Either 100 mL (groups 1 and 2) or 120 mL (groups 3 and 4) of contrast material was injected at a rate of 4 mL/sec. In groups 1 and 3, the scanning delay was fixed, whereas in groups 2 and 4, scanning delays were determined individually by means of a semiautomatic bolus tracking device. The arterial phase began when splenic enhancement was greater than 10 HU and ended when hepatic enhancement was greater than 20 HU, which characterized the start of the portal venous phase. RESULTS: The mean duration of the arterial phase was 11.6 (100 mL) and 12.2 seconds (120 mL). The arterial phase of the liver within the defined limits was sufficiently timed in only 16 (54%) patients in group 1, 25 (83%) in group 2, and 20 (67%) in groups 3, whereas it was significantly (P < .05) better in 28 (93%) patients in group 4. A significantly (P < .05) higher mean parenchymal enhancement in the portal venous phase (63.6 HU +/- 8.5) was obtained in group 4. CONCLUSION: Bolus tracking of a volume of 120 mL provided the most accurate results in dual-phase liver CT.

Adult↗