Implementation of a web-based, interactive polytrauma tutorial in computed tomography for radiology residents: how we do it.

PURPOSE: Due to the time factor in polytraumatized patients all relevant pathologies in a polytrauma computed tomography (CT) scan have to be read and communicated very quickly. During radiology residency acquisition of effective reading schemes based on typical polytrauma pathologies is very important. Thus, an online tutorial for the structured diagnosis of polytrauma CT was developed. MATERIALS AND METHODS: Based on current multimedia theories like the cognitive load theory a didactic concept was developed. As a web-environment the learning management system ILIAS was chosen. CT data sets were converted into online scrollable QuickTime movies. Audiovisual tutorial movies with guided image analyses by a consultant radiologist were recorded. RESULTS: The polytrauma tutorial consists of chapterized text content and embedded interactive scrollable CT data sets. Selected trauma pathologies are demonstrated to the user by guiding tutor movies. Basic reading schemes are communicated with the help of detailed commented movies of normal data sets. Common and important pathologies could be explored in a self-directed manner. CONCLUSIONS: Ambitious didactic concepts can be supported by a web based application on the basis of cognitive load theory and currently available software tools.

Comparison of the image quality of various fixed and dose modulated protocols for soft tissue neck CT on a GE Lightspeed scanner.

PURPOSE: Up-to-date CT scanners provide high quality soft tissue imaging of the neck, but scanning protocols often are not optimized regarding radiation dose. Thus, we tried to find a dose-optimized protocol for soft tissue imaging of the neck. MATERIAL AND METHODS: 70 patients were scanned with a 16-row CT-scanner (Lightspeed, GE) with seven different protocols. We used four fixed tube current settings (225, 200, 175 and 150 mA; corresponding CTDI(vol)=10.6, 9.5, 8.3 and 7.1 mGy) and three z-axis dose modulations with a relatively high, moderate and low dose (calculated CTDI(vol)=10.5, 9.1, 7.7 mGy). Representative slices of seven anatomical regions (from the nasopharynx to the aortic arch) were subjectively judged by two radiologists with respect to image quality (five-point rating scale for noise and sharpness). For each protocol and for each judged anatomical region we determined and compared mean values regarding image quality and local tube current. For each protocol, mean values regarding the volume CT dose index (CTDI(vol)) and the dose-length product (DLP) were statistically compared. Moreover, using the software CT-Expo the respective effective doses and the cumulative organ doses of the thyroid gland were compared. RESULTS: For a fixed tube current of at least 200 mA (CTDI(vol)=9.5 mGy) and for dose modulations with a moderate or high dose adjustment (calculated CTDI(vol)=9.1 and 10.5 mGy) the image quality was sufficient to excellent. As compared to a fixed tube current of 200 mA, dose modulation with a moderate dose adjustment improved the image quality in regions more vulnerable to noise-related artifacts such as at the level of the shoulder, without a noteworthy difference regarding the DLP. However, the cumulative organ dose of the thyroid gland was 17% lower using dose modulation with a moderate dose adjustment as compared to the fixed tube current of 200 mA. Thus, for a comparison with other scanners, we recommend dose modulation and an averaged CTDI(vol)<9 mGy (or a DLP<250 mGycm). CONCLUSION: A combination of dose modulation and an averaged CTDI(vol)<9 mGy or a DLP<250 mGycm yields sufficient image quality for soft tissue CT-imaging of the neck.

Oral and oropharyngeal tumors.

There is a large variability of tumors and tumor-like lesions, which are located in the oral cavity and oropharynx. But more than 90% of all tumors in this area are squamous cell carcinomas (SCCs). Other malignancies in this location are rare. About 10% of all oral and oropharyngeal tumors are benign. Congenital lesions, like vascular malformations, lingual thyroid or (epi-)dermoid cyst, usually become present in youth or childhood. Acquired lesions can be inflammatory (abscess) or neoplastic (pleomorphic adenoma and hemangioma). Preferred imaging in childhood are ultrasound and magnetic resonance imaging (MRI), while in adults usually computed tomography (CT) and MRI are more frequently used.

Course and relevance of arteriovenous fistulas after renal transplant biopsies.

Arteriovenous fistulas (AVFs) after renal transplant biopsy are considered harmless. However, verification of the clinical course has not been thoroughly documented. We evaluated the data of our outpatient renal transplant biopsy program regarding the clinical course of AVFs after 2824 biopsies since 2000. We also reviewed all selective renal transplant embolizations. AVFs were the most frequent biopsy complications (8.3%). Seventy-seven percent of AVFs disappeared spontaneously. Renal function in patients with AVFs was not different compared to those without during 2 years of observation. There were no differences in AVFs comparing protocol or indication biopsies, needle size, the time after transplantation, the use of acetylic salicylic acid or serum-creatinine at biopsy. Living or younger donors were less likely to get postbiopsy AVFs. Ten embolizations were performed. Only one patient was from our outpatient biopsy program. Nine others were biopsied as inpatients in the course of complications during 6 weeks after transplant. Six of nine successfully embolized patients profited with improvement of renal function. Large AVFs occur most commonly shortly after transplantation in patients with poor graft function. There is no established test predicting which patient will benefit from embolization; however, Doppler-determined resistive index may help in this regard.

[Fair in the face: modern diagnostics of midfacial trauma]. / Mitten ins Gesicht: Moderne bildgebende Diagnostik beim Gesichtsschädeltrauma.

Modern diagnostics of midfacial trauma are embedded in a diagnostic concept that is oriented to the therapeutic relevance for the individual. Critical analysis of the indicated and efficient radiological method in the acute phase shows that MSCT is currently the method of choice in the diagnosis of midfacial trauma. Besides extensive acquisition of data in the shortest time the possibilities of modem post-processing provide a three-dimensional picture of the often complex injuries in real time. Other perilous injuries are often more important especially for the polytrauma patient. With modern scan protocols intracranial injuries as well as injuries of bone and soft tissue of the head and neck region can be diagnosed during a single examination. Radiology plays a key role for the economically oriented strategy of patient care.

Physiologic and pathologic calcifications and ossifications in the face and neck.

The aim was to give a systematic presentation of physiologic and pathologic calcifications and ossifications in the face and neck with a special emphasis on clinical relevance. In a sometimes subacute setting one should recognize specific calcifications which often lead to important diagnoses such as fungal sinusitis or sclerosing labyrinthitis. In a more chronic situation intraocular calcifications in small children are pathognomonic for retinoblastoma. Juxtatumoral sclerosis of the laryngeal cartilage in laryngopharyngeal carcinoma is usually caused by tumor infiltration of the cartilage resulting in a higher tumor stage and, this way, has a major impact on the therapeutical strategy. Calcified lymph nodes are mainly unspecific but can be the result of tuberculosis or metastases of thyroid cancer. Cross-sectional imaging methods, most of all computed tomography, are ideally suited to reveal head and neck calcifications and ossifications, especially those which are clinically relevant.

[Value of radiological methods in the diagnosis of biliary diseases]. / Stellenwert der radiologischen Verfahren bei Erkrankungen von Gallenblase und -wegen.

The modern cross-sectional radiological methods of ultrasound, computed tomography, and magnetic resonance imaging provide manifold possibilities for the diagnosis of inflammatory and tumorous diseases of the gallbladder and the bile ducts as well as stone-related diseases. The invasive methods for direct imaging of the bile ducts, such as endoscopic retrograde cholangiopancreatography, are mainly used within therapeutic concepts. According to the literature, ultrasound and magnetic resonance imaging show a sensitivity of up to 100% in the diagnosis of intra- and extrahepatic cholestasis, but concerning the diagnosis of the cause of cholestasis these methods are limited. Therefore, additional MRI sequences or computed tomography are necessary. Computed tomography is particularly efficient for the diagnosis of the biliary system and adjacent anatomical and pathological structures within the pre- and postoperative period.

[Individualized dose requirement for spiral-CT analysis of the abdomen]. / Individueller Dosisbedarf bei Spiral-CT-Untersuchungen des Abdomens.

PURPOSE: To search for individualized scan protocols that provide adequate diagnostic information with minimal radiation exposure for abdominal CT in adults. MATERIAL AND METHODS: Beginning with standard settings (120 kVp, 200 mA, 0.75 s, CTDI (w = 11.7 mGy)), which are in the lowest quartile of the actual German radiation dose survey, 119 adults were examined using a single-row detector helical CT with 8 mm collimation and a pitch of 1.5. The individualized scan protocol was defined by repeating the reference scan up to 3 times with different radiation doses following a predefined iteration scheme. The image qualities with standard dose and with individualized dose were assessed independently by 3 radiologists blinded to the exposure parameters. The individualized dose was correlated with the diameter of the patients. RESULTS: The patient diameters varied from 16 to 35 cm and correlated with individualized radiation doses CTDI (w) from 6.4 to 17.6 mGy. We found an exponential correlation (y = 52.3 x e (0.05 x); r(2) = 0.48; p < 0.001) between required tube current (mA) and a. p. diameter (cm) in the epigastric region in adults. CONCLUSION: Maintaining constant exposure parameters results in unnecessary radiation exposure in patients with a diameter of less than 27 cm measured in anterior-posterior direction in the epigastric area. The radiation exposure in adult abdominal CT can be reduced up to 45 % by individualized selection of the tube current without adversely affecting diagnostic performance.

Functional MR imaging of submandibular herniation of sublingual tissues through a gap of the mylohyoid muscle in two cases of submandibular "masses".

Except for neoplasms, in symptomatic patients with submandibular swellings, gaps of the mylohyoid muscle may be the cause of herniations of sublingual tissues, such as fat and/or the sublingual gland. In two patients with a submandibular swelling, MRI with standard sequences including contrast enhancement was performed to exclude a neoplastic lesion. In addition, we performed a trueFISP sequence during modified Valsalva's maneuver. In both patients, a neoplasm was excluded. Instead, the trueFISP sequence during the modified Valsalva's maneuver showed submandibular herniation of sublingual tissues. If MRI of the floor of the mouth does not show a neoplasm, an additional functional MR investigation should be performed. Gaps of the mylohyoid muscle can be the cause of herniating sublingual tissues (similar to plunging ranulas). During the modified Valsalva's maneuver, sublingual fat and/or gland can herniate and cause a symptomatic submandibular swelling. A coronal trueFISP sequence is particularly suited to demonstrate this.

[Diagnostic impact of multiplanar reformations in multi-slice CT of laryngeal and hypopharyngeal carcinomas]. / Diagnostischer Nutzen multiplanarer Reformationen bei der Mehrschicht-CT von Larynx- und Hypopharynxkarzinomen.

PURPOSE: Assessment of the diagnostic value of multiplanar reformations (MPR) in multi-slice computed tomography (MSCT) by comparing relevant anatomic structures of the larynx and hypopharynx. MATERIALS AND METHODS: MSCT of the neck was performed in 69 consecutive patients (including 30 laryngeal and 12 hypopharyngeal carcinomas). From a 4 x 1.0 mm collimation data set, 3.0-mm and 1.25-mm axial slices as well as 3-mm coronal and sagittal slices were reconstructed. Using the histological examination as gold standard, sensitivity and specificity regarding tumor infiltration for all relevant anatomical structures of the larynx and the hypopharynx were determined for each reconstruction and compared with the McNemar test. Moreover, 42 patients with laryngeal and/or hypopharyngeal carcinoma were subjectively evaluated to determine whether the respective reconstructions enables a better topographical visualization of the tumor in relation to surrounding structures and, furthermore, whether this has an influence on the therapeutical strategy (operation versus radiation therapy, type of operation, surgical approach). RESULTS: Sensitivities and specificities were not significantly different between the reconstructions. However, coronal and sagittal MPR provided a better topographical visualization of the tumor in 14 of 42 (33 %) of the patients, and influenced the therapeutical strategy in 8 of 42 (19 %) of the patients. A lowered signal-to-noise ratio impeded the evaluation of the relatively thin 1.25-mm axial slices in more than 23 % of the cases. CONCLUSION: Besides the 3-mm axial slices, coronal and sagittal MPR can improve the topographical visualization of laryngopharyngeal tumors and are recommended for preoperative MSCT of laryngeal and/or hypopharyngeal carcinomas. Additionally reconstructed 1.25-mm axial slices can be discarded since they do not hold a higher value compared to 3-mm axial reconstructions.

[Prognostic value of pretreatment CT regarding local control in oropharyngeal cancer after primary surgical resection]. / Computertomographische Vorhersagbarkeit Lokaler Rezidive nach primär operativer Resektion von Oropharynxkarzinomen.

PURPOSE: To evaluate the prognostic implication of tumor infiltration and volume in primarily operated oropharyngeal carcinomas. MATERIAL AND METHODS: In 80 patients with oropharyngeal squamous cell carcinomas (pT 1 = 22, pT 2 = 30, pT 3 = 19 and pT 4 = 9), the tumor volume was measured by pretreatment CT and the extent of tumor infiltration determined by postoperative histologic examination. All patients were followed clinically for local tumor recurrence for at least two years after therapy. The statistical analysis consisted of chi 2 and U tests. RESULTS: The local control rate was 79 % (63/80). Of all evaluated anatomic structures, only midline crossing correlated significantly with local recurrence (p = 0.06). No correlation of tumor volume (p = 0.19) or T stage (p = 0.60) with the local recurrence rate was found. CONCLUSION: After primary surgery, oropharyngeal carcinomas with midline crossing have an increased risk of local recurrence, whereas the tumor volume only has a minor impact on the recurrence rate. This is in contrast to laryngeal or hypopharyngeal carcinomas.

Current concepts in imaging of laryngeal and hypopharyngeal cancer.

In adjunct to direct laryngoscopy, CT and/or MRI are needed for an accurate staging of laryngeal and hypopharyngeal carcinomas because both cross-sectional imaging modalities are known to reliably evaluate deep tumor infiltration. Except for the clinical background, this article reviews technical aspects of CT and MRI, the pathologic appearance of laryngeal and hypopharyngeal carcinomas, and therapeutically relevant diagnostic aspects.

High resolution ultrasound detects a decrease in pannus vascularisation of small finger joints in patients with rheumatoid arthritis receiving treatment with soluble tumour necrosis factor alpha receptor (etanercept).

OBJECTIVE: High resolution ultrasound (HRUS) was used to investigate the effects of tumour necrosis factor alpha (TNFalpha) blockade on pannus formation and vascularisation of small finger joints in patients with active rheumatoid arthritis (RA). METHODS: Five patients with active RA were treated with etanercept, a soluble TNFalpha receptor protein, for one month. Before, during, and after treatment the patients were followed up by clinical rheumatological examination, determination of their subjective pain score, blood chemistry, and by HRUS of the second metacarpophalangeal (MCP) joint of the right hand. RESULTS: One month after treatment with etanercept, rheumatological examination showed a significant decrease in a modified single joint rheumatic disease activity index (from 2.9 (SD 0.2) to 1.2 (0.7); p<0.05) in all patients. Moreover, a significant decrease in the general pain score (from 4.7 (0.4) to 1.8 (0.6); p<0.05) and in C reactive protein (CRP) levels was seen (from 3.02 (0.9) to 0.24 (0.1); p<0.05). Concordantly, HRUS showed a significant reduction in pannus vascularisation of the MCPII joints (from 23,602 (5339) to 2907 (1609) colour signals/region of interest, CS/ROI; p<0.001). Pearson's correlation coefficient between the results obtained by HRUS and the clinical response was 0.85. CONCLUSION: HRUS is promising as an additional useful method in the assessment of RA activity, and probably also in monitoring therapeutic responses.

Hepatic angiomyoma: CT and MRI findings.

Angiomyoma is a benign tumor that arises from soft muscular tissue within the blood vessel wall. This lesion has been found in different organs. The preferential location of these tumors is the lower extremity. We describe the rare case of a hepatic angiomyoma and present the radiologic findings of computed tomography and magnetic resonance imaging.

Spiral CT of the neck: When do neck malignancies delineate best during contrast enhancement?

The aim of this study was to determine the time of best contrast of neck malignancies in contrast-enhanced CT. The CT was done in 20 patients with squamous cell carcinoma using a standard protocol (100 ml contrast agent at 2 ml/s). Dynamic series of the tumors were performed (scan interval 6 s). In all relevant structures of the neck, densities were measured to obtain time-density curves. The best tumor contrast was measured > or =50 s after the start of the injection, and the best contrast of lymph nodes < or =75 s. For staging and volume measurements of neck primaries the best achievable contrast is necessary. Using the examined single-bolus technique, spiral CT allows a combination of perfect tumor contrast with a good contrast between lymph nodes and neck vessels between 50 and 75 s after starting the injection.

Comparison of axial reconstructed ultrasonographic images from three-dimensional data volumes and computed tomographic scans in the documentation and detection of liver lesions.

OBJECTIVE: To compare axial reconstructed ultrasonographic images from three-dimensional data volumes and conventional computed tomographic scans in documentation and detection of liver lesions. METHODS: The livers of 23 patients were examined by a multifrequency curved array transducer to acquire three-dimensional data volumes and by conventional computed tomography The ultrasonographic device was equipped with three-dimensional ultrasonographic technology allowing for real-time parallel movement in every plane within an acquired data volume. Axial ultrasonographic images reconstructed from three-dimensional data volumes were compared with conventional computed tomographic scans. RESULTS: When both methods were taken together, a total of 51 different liver lesions could be detected. Reconstructed ultrasonographic images depicted 44 (86%) of 51 lesions, and computed tomographic scans showed 46 (90%) of 51 lesions. Compared with computed tomography, ultrasonography depicted 5 additional lesions in 3 of the patients (4 hemagiomas and 1 unspecified lesion), whereas 7 lesions were missed in another 4 patients (4 metastases, 2 calcifications, and 1 cyst). The Pearson correlation coefficient between ultrasonography and computed tomography was r = 0.84 (P < .001). CONCLUSIONS: Our study shows that ultrasonographic images can be effectively reconstructed from three-dimensional data volumes. With respect to documentation and detection of liver lesions, the results obtained by three-dimensional ultrasonography appear comparable with those obtained by conventional computed tomography. However, several technical and procedural limitations have to be respected.

[Comparison of iodinated and barium-containing contrast media of different viscosity in the detection of pharyngeal perforation]. / Vergleich von jodhaltigem und bariumhaltigem Kontrastmittel unterschiedlicher Viskosität bei der Detektion pharyngealer Perforationen.

PURPOSE: In contrast to esophageal perforations, the more radiopaque barium-suspensions are not as important as iodinated aqueous contrast agents for the detection of pharyngeal perforations. This study was performed to find out whether the highly different viscosities (of iodinated and barium-containing contrast agents with comparable radiopacities) are a reason for this. METHODS: Viscosity, subjective difference in contrast, and CT-density of an iodinated aqueous (Telebrix) and a 50 wt/vol% barium-containing contrast agent (Micropaque) were determined. Moreover, to exclude postoperative perforation, 104 patients were prospectively examined by pharyngography using both contrast media. Pharyngographies of patients with perforation were later compared by two independent readers. All patients with perforation were followed up clinically to exclude complications due to barium administration. RESULTS: In-vitro comparison showed comparable radiopacity but the 50 wt/vol% barium-suspension was much more viscous than the iodinated contrast agent. During pharyngography, totally, 14 perforations were clearly delineated with the iodinated aqueous contrast agent. However, two of them were not detected with the barium-suspension. All the other perforations presented equally. CONCLUSIONS: Given a sufficient radiopacity, a low viscosity appears to be essential for a contrast agent to detect especially pharyngeal perforations. Thus, we recommend the sole use of an iodinated contrast agent (at suspicion of aspiration as isoosmolar variant) for this purpose.