Biomedical subjects

A Ba-Ssalamah

Publications and source records attributed to A Ba-Ssalamah.

At least 19 recordsLinked to original sources

PubMed2006

[Pancreas. Part I: congenital changes, acute and chronic pancreatitis].

The pancreas develops from ventral and the dorsal buds, which undergo fusion. Failure to fuse results in pancreas divisum, which is defined by separate pancreatic ductal systems draining into the duodenum. Risk of developing pancreatitis is increased in pancreas divisum because of insufficient drainage. MR cholangiopancreatography (MRCP) is the technique of choice for detecting pancreas divisum non-invasively. Annular pancreas is the result of incomplete rotation of the pancreatic bud around the duodenum with the persistence of parenchyma or a fibrous band encircling (and sometimes stenosing) the duodenum. Acute pancreatitis is usually caused by bile duct stones or alcohol abuse. The Atlanta classification differentiates between mild acute and severe acute pancreatitis associated with organ failure and/or local complications such as necrosis, abscess or pseudocyst. Contrast-enhanced multi-detector row CT is the method of choice to assess the extent of disease. Balthazar et al.'s CT severity index assesses the risk of mortality and morbidity. In acute pancreatitis, the role of MRCP is mainly limited to finding bile duct stones in patients with suspected biliary pancreatitis. Chronic pancreatitis results in relentless and irreversible loss of exocrine (and sometimes endocrine) function of the pancreas. MDCT even shows subtle calcifications. MRCP is the method of choice for non-invasive assessment of the duct. Inflammatory pseudotumor in chronic pancreatitis and groove pancreatitis are difficult to differentiate from pancreatic cancer. In these cases, multiple imaging methods such as MDCT, MRI and endosonography including biopsy may be used to make a diagnosis.

Acute Disease↗

PubMed2006

[Pancreas. Part II: Tumors].

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head in 60-70% of cases. By the time of diagnosis, approximately 80% of tumors are unresectable. Helical CT is very effective in detection and staging of adenocarcinoma, with a sensitivity of 76-92% for detection and an accuracy of 80-90% for staging, but it has limitations in the detection of small cancers (< or =2 cm). Multidetector CT (MDCT) has brought substantial improvements with its inherent 3D imaging capability. Mangafodipir-enhanced MRI is a problem-solving tool in the depiction of small cancers following an equivocal CT imaging result. Gadolinium-enhanced 3D gradient-echo MRI is helpful in the assessment of vascular invasion of cancer and in determining the etiology of cystic lesions. Serous cystadenoma is benign, has a lobulated contour and contains innumerable small cysts of 0.1-2 cm in diameter. Mucinous cystic neoplasms are unilocular or multilocular (fewer than six cysts), and the cyst diameter exceeds 2 cm. The presence of solid nodular components should alert the radiologist to suspect cystadenocarcinoma. Neuroendocrine tumors are mostly hypervascular. Diagnosis of insulinoma is a challenge: they are <2 cm in 90% of cases and mostly hypervascular at CT or MRI. A combination of contrast-enhanced MDCT, MRI, endosonography, and/or somatostatin receptor scintigraphy is used to detect these small tumors. This review summarizes the imaging features of the most common pancreatic tumors and discusses the limitations of CT, MRI and endosonography.

Adenocarcinoma↗

PubMed2005

[Percutaneous liver biopsy. Overview of different techniques].

To classify a liver tumor, image-guided percutaneous biopsy of a liver lesion is indicated. Using ultrasound (US) to guide a biopsy needle into a liver lesion has been proven useful and safe. If a lesion cannot be seen on US or the access to a lesion has been complicated by its position, CT-guided biopsy can be performed. If a lesion cannot be delineated on US or CT, MR-guided biopsy is recommended. Using hepatospecific contrast agents, the time span to delineate tumor tissue can be prolonged. To differentiate diffuse liver disease, transvenous biopsy under fluoroscopic control can be performed if a percutaneous biopsy is contraindicated. In recent years fine-needle aspiration biopsy has been increasingly replaced by coaxial 14-20 G core biopsy, which is a safe and efficient technique to classify liver lesions and has a low complication rate.

Biopsy, Fine-Needle↗

PubMed2005

[Multidetector computed tomography of the liver].

Multidetector-row CT (MDCT) scanners have dramatically improved liver imaging. With the newest generation of 40-64 row scanners, true isotropic imaging with a z-axis resolution of 0.3-0.6 mm has become possible. Acquisition time for the scan has been shortened to a few seconds. To fully exploit the advantages of MDCT scanners in liver imaging, the examination protocols have to be optimized with regard to contrast material flow rate, scan delay, and the number of scans performed. The possible advantages of double arterial phase scans in the detection of HCC are discussed. The clinical value of 3D reconstructions, such as multiplanar reconstructions and curved planar reconstructions, for assessment of the vascular and biliary duct infiltration is demonstrated. Optimized MDCT imaging improves detection and characterization of focal liver lesions.

Bile Duct Neoplasms↗

PubMed2005

The value of high-field MRI (3T) in the assessment of sellar lesions.

The aim of this study was the evaluation of the normal sellar anatomy in vitro and in vivo with high-field MRI and its application in the diagnosis of sellar pathologies in comparison to standard MRI. All high-field MR images were obtained using a 3T Bruker Medspec 30/80 Scanner with a head birdcage transmit/receive coil and an actively shielded gradient system with a maximum gradient strength of 45 mT/m. Firstly an in vitro study of the sella turcica was performed to depict normal pituitary and sellar anatomy at high field. After a pilot-study this sequence-protocol was established: A RARE sequence (TR/TE = 7790/19 ms; matrix size, 512 x 512; RARE factor = 8, FOV, 200 mm) was used for T2-weighted coronal, axial and sagittal images. A 3D gradient echo sequence with magnetization-preparation (MP-RAGE, TR/TE/TI = 33.5/7.6/800 ms, matrix size, 512 x 512; FOV, 200 mm, effective slice thickness, 1.88 mm; 3 averages) was used for acquisition of T1-weighted pre- and post-contrast images. Between January 2002 and March 200458 patients were enrolled in this study. Seven patients were examined for suspected microadenoma and in 51 patients 3T MRI was used to obtain additional information about the sellar lesion already known to be present from standard MRI. In 21 cases the accuracy of the imaging findings was assessed afterwards by comparison with intraoperative findings. The infiltration of the medial cavernous sinus wall was suspected on standard MRI on 15 sides (47%), on high-field MRI on 9 sides (28%) and could be verified by intraoperative findings on 6 sides (19%). Accordingly, sensitivity to infiltration was 83% for 3T and 67% for standard MRI. Specificity was 84% for 3T and 58% for standard MRI. Moreover, high-field MRI revealed microadenomas in 7 patients with a median diameter of 4mm (range 2-9 mm). The segments of the cranial nerves were seen as mean 4 hypointense spots (range 2-5 spots) on high-field MRI in contrast to 3 spots (range 0-4 spots) on standard MRI. This difference was considerably significant (P < 0.001, Wilcoxon rank sum test). The histopathological results revealed pituitary adenoma in 16 patients and non-adenomatous sellar pathologies such as Rathke's cleft cyst, sarcoidosis, meningeoma and metastasis in 5 patients. High-field MRI is superior to standard MRI for the prediction of invasion of adjacent structures in patients with pituitary adenomas and improves surgical planning of sellar lesion.

Adenoma↗

PubMed2004

Impact of high field (3.0 T) magnetic resonance imaging on diagnosis of osteochondral defects in the ankle joint.

OBJECTIVE: To evaluate high field magnetic resonance (MR) imaging for imaging of osteochondral defects. MATERIALS AND METHODS: Nine osteochondral defects were simulated in three cadaveric talus specimens using a diamond drill. All specimens were examined on a 1.0 T MR unit and a 3.0 T MR unit. A T2-weighted turbo spin-echo (TSE) sequence with a 2 mm slice thickness and a 256 x 256 matrix size was used on both scanners. The visibility of the osteochondral separation and the presence of susceptibility artifacts at the drilling bores were scored on all images. RESULTS: Compared to the 1.0 T MR unit, the protocol on the 3.0 T MR unit allowed a better delineation of the disruption of the articular cartilage and a better demarcation of the subchondral defect. Differences regarding the visualization of the subchondral defect were found to be statistically significant (P<0.05). Differences with regard to susceptibility artifacts at the drilling bores were not statistically significant (P>0.05). The average SNR was higher using 3.0 T MRI (SNR=12), compared to 1.0 T MRI (SNR=7). CONCLUSION: High field MRI enables the acquisition of images with sufficient resolution and higher SNR and has therefore the potential to improve the staging of osteochondral defects.

Ankle Joint↗

PubMed2004

[Use of contrast agent in high-field MRI (3 T)].

The basic diagnostic efficacy of MR contrast medium in the evaluation of primary brain tumors and its clinical usefulness in the detection of brain metastases with single and cumulative triple-dose was compared using a high-field 3 T MR unit and a 1.5 T MR unit. Additionally, the effect of contrast agent on high-resolution MR venography based on the BOLD effect was evaluated at both field strengths. Tumor-brain contrast after gadodiamide administration, as assessed by means of statistical evaluation of MP-RAGE scans and T1-SE images, was significantly higher at 3 T than at 1.5 T. The subjective assessment of cumulative triple-dose 3 T images obtained the best results in the detection of brain metastases, followed by 1.5 T cumulative triple-dose enhanced images. Due to higher spatial resolution, contrast-enhanced MR venography at 3 T showed more details in and around tumors than at 1.5 T, additionally enhanced by stronger susceptibility weighting and higher signal-to-noise ratio at 3 T. In summary, administration of gadolinium-based contrast agent produces higher contrast between tumor and normal brain at 3 T than at 1.5 T, helps to detect more cerebral metastases at 3 T than at 1.5 T in single and cumulative triple dose, and improves MR venography at 3 T with increase in spatial resolution within the same measurement time, thus providing more detailed information.

Adult↗

PubMed2004

[MRT of the liver. Clinical significance of nonspecific and liver-specific MRT contrast agents].

The liver is a common site for various benign and malignant focal lesions. The initial modality for assessing liver lesions is ultrasound or CT. MRI with its superior soft tissue contrast offers multiple advantages over other imaging modalities. Contrast agents have been developed that increase the detection rate and provide more specific information in comparison to unenhanced techniques. In the mean time three classes are available for MR imaging of the liver: extracellular gadolinium chelates, hepatobiliary and reticulo-endothelia, superparamagnetic agents. We describe in this review the most common focal lesions, their diagnostic possibilities, and the imaging protocols. Clinical use of these contrast agents facilitates detection and differential diagnosis of focal liver lesions that may help to avoid invasive procedures such as biopsy for lesion characterization.

Chelating Agents↗

PubMed2004

Rotator cuff tears in asymptomatic individuals: a clinical and ultrasonographic screening study.

OBJECTIVE: To determine the prevalence and clinical impact of rotator cuff tears in asymptomatic volunteers. MATERIALS AND METHODS: Sonographic examinations of the shoulder of 212 asymptomatic individuals between 18 and 85 years old were performed by a single experienced operator. The prevalence and location of complete rotator cuff tears were evaluated. The clinical assessment was based on the Constant Score. Magnetic resonance imaging (MRI) of the shoulder was obtained in those patients where US showed rotator cuff pathology. RESULTS: Ultrasound showed a complete rupture of the supraspinatus tendon in 6% of 212 patients from 56 to 83 years of age (mean: 67 years). MRI confirmed a complete rupture of the supraspinatus tendon in 90%. All patients reported no functional deficits, although strength was significantly lower in the patient group with complete supraspinatus tendon tear (P < 0.01). CONCLUSION: There is a higher prevalence in older individuals of rotator cuff tendon tears that cause no pain or decrease in activities of daily living.

Activities of Daily Living↗

PubMed2003

Spiral CT and radiation dose.

Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers-patients and medical doctors who are non-radiologists-that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information.

Europe↗

PubMed2001

Equipment availability and diagnostic strategies for suspected pulmonary embolism in Austria.

The aim of this study was to investigate equipment availability and current diagnostic strategies for suspected pulmonary embolism (PE) in Austrian hospitals. A questionnaire was sent to the medical directors of all Austrian hospitals with emergency and/or surgical, orthopedic, and medical departments. The questionnaire contained questions regarding the available equipment suitable for the imaging diagnosis of PE, the first-line and second-line imaging tests for patients with suspected PE, and additional lower extremity venous imaging and laboratory tests that complement the diagnostic armamentarium. The return rate for questionnaires was 81% (127 of 157 hospitals). There were 97% of hospitals that had the equipment to perform sonography, 59% could perform pulmonary angiography, 54% spiral CT, 19% ventilation/perfusion (V/P) scintigraphy, and 4% perfusion scintigraphy alone. Spiral-CT angiography (SCTA) was the first-line imaging study for suspected PE in 56% of hospitals, followed by echocardiography and V/P scintigraphy. Lower extremity venous imaging (47%) and, interestingly, V/P scintigraphy (43%), served as second-line imaging tests. D-dimer tests were included in the diagnostic strategy in 74% of hospitals. Spiral-CT angiography is the most commonly used primary method for suspected PE in Austrian hospitals. The V/P scintigraphy is available only in a minority of hospitals to investigate patients with suspected PE. When V/P scintigraphy is available, however, it is employed in a large number of patients per annum.

Austria↗

PubMed2001

Displacement of coils into the lung during embolotherapy: clinical importance and follow-up with helical CT.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the clinical importance and computed tomographic (CT) appearance of coils displaced into the lung during embolotherapy. MATERIALS AND METHODS: The authors retrospectively studied clinical charts and serial chest images from 25 consecutive patients after coil embolization. Chest radiography was performed in all patients, whereas helical chest CT was performed only in patients in whom dislocated coils were visible on chest radiographs. Coils were applied for the treatment of peripheral arteriovenous (AV) malformations and fistulas (n = 9), renal AV malformations or fistulas (n = 8), and primary or secondary tumors (n = 8). Clinical charts were analyzed for short- and long-term symptoms; chest radiographs and CT scans were reviewed for signs indicative of pulmonary infarction. RESULTS: None of the patients had clinical symptoms suggestive of pulmonary infarction. In two of the 25 patients (8%), displaced coils were seen in the pulmonary vasculature at chest radiography; these patients had been treated for renal AV fistula and peripheral AV fistula, respectively. One patient had two coils in the left hemithorax (upper and lower lobe), and the other patient had two coils in the right hemithorax (middle lobe). Neither of the patients had abnormalities suggestive of pulmonary infarction at helical CT. CONCLUSION: Chest radiography can help confirm the presence of coils displaced to the pulmonary vasculature during embolotherapy. Helical CT can also help rule out the presence of coil-associated pulmonary infarction.

Adolescent↗

PubMed2001

Scaphoid fractures: evaluation with high-spatial-resolution US initial results.

PURPOSE: To evaluate the diagnostic accuracy of high-spatial-resolution ultrasonography (US) in the diagnosis of scaphoid fractures. MATERIALS AND METHODS: In 72 hours after acute wrist trauma, 15 consecutive patients were examined for possible scaphoid fractures clinically and with conventional radiographs, including scaphoid views. Thereafter, high-spatial-resolution US was performed by two experienced radiologists blinded to the results of the previously performed investigations. High-spatial-resolution US of the scaphoid bones was performed from the palmar, lateral, and dorsal directions in the longitudinal and transverse planes. US findings indicative of a scaphoid fracture were cortical discontinuity and/or periosteal elevation. Finally, magnetic resonance (MR) images (short inversion time inversion-recovery, T1- and T2*-weighted) (ie, the standard) of the affected wrist were obtained and evaluated for a possible scaphoid fracture by two radiologists in consensus. RESULTS: Nine of 15 patients had scaphoid fractures. Seven (78%) of nine patients had positive findings at high-spatial-resolution US and five (56%) had such findings at conventional radiography (ie, four occult scaphoid fractures), with an accuracy of 87% and 73%, respectively. Two (50%) of four radiographically occult scaphoid fractures were depicted with high-spatial-resolution US. Sonographic findings of scaphoid fractures were either cortical discontinuity (n = 4), periosteal elevation (n = 2), or a combination of these two findings (n = 1). CONCLUSION: High-spatial-resolution US is a reliable diagnostic tool for the evaluation of occult scaphoid fractures and should be considered an adequate alternative diagnostic tool prior to computed tomography or MR imaging.

Adolescent↗

PubMed2000

Detection of focal hepatic lesions: comparison of unenhanced and SHU 555 A-enhanced MR imaging versus biphasic helical CTAP.

The purpose of this study was to compare the diagnostic sensitivity of unenhanced magnetic resonance (MR) imaging, and MR imaging with a new superparamagnetic iron oxide (SPIO)-enhanced contrast agent (SHU 555 A) with biphasic helical computed tomography during arterial portography (CTAP) in patients with focal liver lesions. Eighteen patients with a total of 91 (78 malignant, 13 benign) proven liver lesions underwent unenhanced short tau inversion recovery (STIR), T2-weighted (T2-w) TSE, and SHU 555 A-enhanced T2-w turbo spin-echo (TSE) MR imaging and biphasic helical CTAP. The standard of reference was histopathologic analysis of resected specimens in 59 lesions, intraoperative ultrasound with biopsy in 20 lesions, and CT-guided biopsy and follow-up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion involvement in liver segments. There were 68 lesions detected on unenhanced T2-w TSE, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesions were detected, for a sensitivity of 84%, and with SHU 555 A-enhanced MRI, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesions, for a sensitivity of 97%. The accuracy for unenhanced T2-w TSE was 98%, for STIR 99%, for enhanced-MRI 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A-enhanced MRI and 95% for CTAP. SHU 555 A-enhanced MRI was superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false-positive results on SHU 555 A-enhanced MRI, the specificity and accuracy of enhanced MRI were higher than those of CTAP, but the difference was not statistically significant (P = 0.134).

Adult↗

PubMed2000

Report generation using digital speech recognition in radiology.

The aim of this study was to evaluate whether the use of a digital continuous speech recognition (CSR) in the field of radiology could lead to relevant time savings in generating a report. A CSR system (SP6000, Philips, Eindhoven, The Netherlands) for German was used to transform fluently spoken sentences into text. Two radiologists dictated a total of 450 reports on five radiological topics. Two typists edited those reports by means of conventional typing using a text editor (WinWord 6.0, Microsoft, Redmond, Wash.) installed on an IBM-compatible personal computer (PC). The same reports were generated using the CSR system and the performance of both systems was then evaluated by comparing the time needed to generate the reports and the error rates of both systems. In addition, the error rate of the CSR system and the time needed to create the reports was evaluated. The mean error rate for the CSR system was 5.5%, and the mean error rate for conventional typing was 0.4%. Reports edited with the CSR, on average, were generated 19% faster compared with the conventional text-editing method. However, the amount of error rates and time savings were different and depended on topics, speakers, and typists. Using CSR the maximum time saving achieved was 28% for the topic sonography. The CSR system was never slower, under any circumstances, than conventional typing on a PC. When compared with a conventional manual typing method, the CSR system proved to be useful in a clinical setting and saved time in generating radiological reports. The amount of time saved, however, greatly depended on the performance of the typist, the speaker, and on stored vocabulary provided by the CSR system.

Humans↗

PubMed2000

Dolichoodontoid. A rare cranio-cervical anomaly--MRI findings.

The case of a 40-year-old woman with a dolichoodontoid, a rare congenital anomaly of the cranio-cervical region, is presented. Due to summation image and overlying bony structures, plain radiographs in two planes were inconclusive. MRI revealed the hyperplasia of the odontoid process, allowed a grading of the subtype of this disorder and demonstrated its relationship to the neural structures within the foramen magnum and the upper cervical spine. Additional inflammatory disease, suspected in this patient with long standing rheumatoid arthritis could be excluded by MRI.

Adult↗

PubMed2000

MR imaging of the ischiopubic synchondrosis.

The ischiopubic synchondrosis (IPS) is a temporary joint, occurring in childhood prior to fusion of the ischial and pubic bones. On conventional radiographs this tumor-like appearance is a well known normal anatomic variant, however, there are no reports in the literature of the appearance of IPS on MRI. Therefore the purpose of this study was to evaluate typical magnetic resonance features of the IPS. All pelvic MRIs from 1/1992 to 4/1998 of children ranging in age from 4 to 16 years, who were scanned for reasons other than bone disorders, were retrospectively investigated. Twenty-eight children were included and the morphologic appearance of IPS on MRI was evaluated. Seventeen (61%) of these 28 children had the following findings of IPS on MRI. Listed in order of frequency we found signal alteration of the ischiopubic fusion zone [hyperintense on T(2) with fat-saturation (89%) or STIR (74%), hypointense on T(1) (71%)], fibrous "bridging" (68%) [hypointense band on all sequences in perpendicular orientation to the axis of the inferior pubic ramus], fusiform swelling (68%), signal alteration of the adjacent soft tissue (57%) and irregular margins (56%). In 10 children contrast enhanced scans were available for evaluation, showing contrast enhancement of the bone marrow in 83.3% and of the adjacent soft tissue in 66.7%. Fusiform swelling of the ischiopubic fusion zone, signal alteration and contrast enhancement of both the bone marrow and the adjacent soft-tissue are characteristic features of the IPS on MRI, which may be due to mechanical stress at this temporary joint. These features are nonspecific and may resemble tumor, infection or trauma. Fibrous "bridging" was the only finding on MRI, which has not been described for any other entity and thus, it seems to be a characteristic MRI-feature.

Adolescent↗

PubMed2000

Preoperative fast MRI of brain tumors using three-dimensional segmented echo planar imaging compared to three-dimensional gradient echo technique.

The purpose of this study was to compare the diagnostic efficacy of a newly developed T(1)-weighted three-dimensional segmented echo planar imaging (3D EPI) sequence versus a conventional T(1)-weighted three dimensional spoiled gradient echo (3D GRE) sequence in the evaluation of brain tumors. Forty-four patients with cerebral tumors and infections were examined on a 1.0 T MR unit with 23 mT/m gradient strength. The total scan time for the T(1) 3D EPI sequence was 2 min 12 s, and for a conventional 3D GRE sequence it was 4 min 59 s. Both sequences were performed after administration of a contrast agent. The images were analyzed by three radiologists. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise and contrast-to-noise-ratio (C/N) were calculated. The gray-white differentiation and C/N ratio of 3D EPI were found to be inferior to conventional 3D GRE images, but the difference was not statistically significant. In the qualitative comparison, lesion detection and conspicuity of 3D EPI images and conventional 3D GRE images were similar, but a tow-fold reduction of the scanning time was obtained. With the 3D EPI technique, a 50% scan time reduction could be achieved with acceptable image quality compared to conventional 3D GRE. Thus, the 3D EPI technique could replace conventional 3D GRE in the preoperative imaging of brain.

Adult↗