[Relevance of disaster and deployment medicine for medical students : A pilot study based on an interdisciplinary lecture series]

BACKGROUND

The global rise of conflicts and catastrophes causes new challenges for western healthcare systems. There are obvious parallels between civilian disaster medicine and military combat care. The integration of disaster and deployment medicine into the medical curriculum thus seems necessary.

OBJECTIVE

What do medical students think about disaster and deployment medicine as part of the curriculum? Does participation in a voluntary disaster medicine course affect their view?

MATERIAL AND METHODS

While participating in an extracurricular lecture series on disaster and deployment medicine students (group 1) were asked about their personal views and prior experience in disaster medicine (20 questions). Students who did not attend the lecture (group 2) functioned as the control group. The statistical evaluation was performed descriptively and using Student's t test for independent subgroups.

RESULTS

The questionnaire was completed by 152 students (group 1: n = 78, group 2: n = 74). Only 10 students in group 1 and none in group 2 felt they had received an adequate amount of teaching in the field of disaster medicine. Medical students in both groups considered disaster medicine to be inadequately represented in the medical curriculum (group 1: 64% and group 2: 66%). Both groups were in favor of further expanding teaching in the field of disaster medicine (group 1: 72%, group 2: 54%, p = 0.001) and the development of e‑learning tools (group 1: 73%, group 2: 72%).

DISCUSSION

The medical students questioned considered disaster and deployment medicine to be an integral part of the curriculum. Despite some statistical differences between the two groups, the survey showed that medical students possess a great interest in disaster medicine. Both groups were in favor of further integrating e‑learning tools. A regular inclusion of disaster and deployment medicine into the spectrum of medical student teaching is warranted.

Advanced Multiple Beam Equalization Radiography (AMBER) Combined with Computed Radiography

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: the SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique.

[Long-term liver damage due to trauma]

Severe trauma has a major influence on the visceral organs, especially on the liver. Splanchnic hypotension leads to necrosis of the bile duct cells as well as to damage to hepatocytes. Furthermore, the liver is a very immunologically active organ so that damage to the liver can increase the amount of proinflammatory cytokines. The major complication of post-traumatic damage to the liver is secondary sclerosing cholangitis (SCC) a highly progressive disease for which there is no sufficient therapy except liver transplantation. Therefore it is very important to put all efforts into avoiding posttraumatic liver damage from the very beginning. A sophisticated resuscitation therapy is the most important aspect. Direct peritoneal volume resuscitation is a promising possibility to improve perfusion of the visceral organs. Other possibilities are substitution with 17beta-estradiol as a strongly vasoactive hormone with a positive effect on liver perfusion and interleukin-10 as modulator of the immune reaction caused by the liver.

[Age- and gender-related distribution of bone mineral density and mechanical properties of the proximal humerus]

PURPOSE

To evaluate age- and gender-related mechanical properties and bone mineral density (BMD) of the proximal humerus at different levels and regions.

MATERIALS AND METHODS

Mechanical indentation testing, DXA, QCT, pQCT and the radiogrammetry (Cortical Index, CI) were carried out in 70 freshly harvested humeri from 46 human cadavers (23 females, 23-males; median age 70.5 years).

RESULTS

In the female group, a high correlation between age and BMD was found (rho = 0.62 to -0.70, p < 0.01) with statistically significant differences between specimens of patients 69 years or younger, and 70 years or older (p < 0.05). In the group of female specimens of age 70 years or older, BMD values were found to be significantly lower compared to their male counterparts (p < 0.05). Regardless of the specimen's age, the highest BMD and bone strength were found in the proximal aspect and in the medial and dorsal regions of the proximal humerus.

CONCLUSION

These findings provide an insight into the fracture mechanism of the proximal humerus and should be the basis for designing structure-oriented implants with improved implant-bone stability in osteoporotic patients.

Combined CT pulmonary angiography and venography for diagnosis of pulmonary embolism and deep vein thrombosis: radiation dose

A major concern about combined pulmonary CT angiography (PCTA) and CT venography (CTV) refers to the additional radiation exposure to the patient. The purpose of this paper is to analyze the organ dose, the effective dose, and the gonadal dose of combined PCTA and CTV. Effective dose and gonadal dose in PCTA and CTV were calculated. Also measured was the organ doses with thermoluminescence dosimeters in six patients who underwent combined PCTA/CTV. The risk from the effective dose and gonadal dose in combined PCTA/CTV is low. Nevertheless, additional CTV increases the gonadal dose by a significant factor and use of this procedure should be limited in younger patients.

[MRI diagnosis of injuries and diseases of peroneal tendons]

Injuries of the peroneus tendons are common and both the athlete and the older population are at risk. MR imaging is a useful technique for revealing injuries of the peroneus tendons as well as showing anatomic factors associated with these lesions. This article reviews clinical factors and MR imaging characteristics of injuries of the peroneus tendons.

Role of high magnification specimen radiography in surgical and core biopsies of the breast

The clinical relevance of a high magnification specimen radiography (HMSR) system in breast biopsies was evaluated and compared with conventional specimen radiography with a mammography system (SRM). 100 surgical biopsies of 72 patients and 248 core biopsies of 30 patients were examined in (a) maximal 20-fold HMSR in combination with storage phosphors and (b) 1.8-fold SRM using a film-screen system. Detection of calcifications/soft tissue lesions and the impact on management were evaluated. In surgical biopsies, SRM could detect only 22% of individual microcalcifications, 39% of calcified lesions and 67% of soft tissue lesions identified with HMSR. Calcifications down to 10 microns were identified with HMSR. In five biopsies, peripheral calcifications leading to additional resection were recognized only with HMSR; in three of these they were indicative of malignant tissue. In core biopsies, only 12% of individual microcalcifications seen with HMSR were identified with SRM. 52% and 16% of all cores were calcified on HMSR and SRM, respectively. Microcalcifications within cores were found only with HMSR in 41% of patients with calcified lesions. In conclusion, the better detectability of microcalcifications with HMSR led to justified additional tissue resections in surgical patients and reduced the number of core biopsies required in interventional patients.

Contrast-enhanced color Doppler sonography for evaluation of enlarged cervical lymph nodes in head and neck tumors

OBJECTIVE

We determined whether contrast-enhanced color Doppler sonography can differentiate benign from malignant enlarged cervical lymph nodes in head and neck tumors.

SUBJECTS AND METHODS

Ninety-four enlarged lymph nodes in 39 adult patients (32 men and seven women; age range, 30-81 years) were examined with B-mode sonography and with unenhanced and contrast-enhanced color Doppler sonography. All patients had carcinoma of the oral cavity. Histologically, lymphadenitis was found in 57 nodes and metastases in 37 nodes. Geometric dimension, texture, and margin of the node and detection and location of vessels were noted. Histology and imaging findings were correlated.

RESULTS

The transverse-to-longitudinal diameter ratio in combination with texture and margin analysis resulted in a correct diagnosis in only approximately 79% of the nodes. With contrast-enhanced color Doppler sonography, 86% of nodes showed vessels, and 28% of nodes showed vessels with this technique exclusively. Characteristic configurations were identified: hilar vessels with branching indicated lymphadenitis (sensitivity, 98%; specificity, 100%), and predominantly peripheral vessels indicated metastases (100%, 98%). These findings changed the diagnosis in 13 nodes, changed the therapy in four patients, and led to an incorrect diagnosis in one patient.

CONCLUSION

Enlarged lymph nodes can be characterized as metastatic or inflammatory with high diagnostic accuracy on the basis of their vascular architecture as seen on contrast-enhanced color Doppler sonography.

67Ga-citrate and 99Tcm-MDP for estimating the severity of vertebral osteomyelitis

The aim of this study was to evaluate the roles of 67Ga-citrate and 99Tcm-methylene diphosphonate (99Tcm-MDP) planar and single photon emission tomographic (SPET) imaging in patients with vertebral osteomyelitis. Thirty patients (22 females, 8 males) aged 62.7 +/- 16.4 years (mean +/- s) were enrolled prospectively between May 1995 and May 1998. The patients had been on antibiotics for 7 +/- 4 weeks prior to the study. Histology was available for all but nine patients with mild infections, who were evaluated by a combination of magnetic resonance imaging (MRI), clinical and laboratory tests. 67Ga-citrate (185 MBq) and three-phase bone (555 MBq 99Tcm-MDP) planar and SPET imaging were performed in all patients, together with MRI as a comparison. In total, 67 infectious foci were detected. Based on histology, there were four cases of severe, 13 cases of moderate and four cases of mild osteomyelitis; nine mild infections were also classified by the combination of MRI, clinical and laboratory results. Combined MRI and 67Ga-citrate SPET correctly classified all patients; MRI detected all 67 infectious foci, whereas 67Ga-citrate SPET identified 54 only. False-negative results were seen with all other modalities, especially in cases of mild and moderate infection. 67Ga-citrate SPET identified unsuspected cases of endocarditis (n = 2), paravertebral abscess (n = 1), subaxillary soft tissue abscess (n = 1) and rib osteomyelitis (n = 1). For 67Ga-citrate SPET, the target-to-background ratio was 2.24 +/- 0.31, 1.76 +/- 0.07 and 1.30 +/- 0.18 for severe, moderate and mild osteomyelitis, respectively. Significant differences were noted between severe and moderate infection (P = 0.0051) and between severe and mild infection (P < 0.0001); that between moderate and mild infection was non-significant. For 99Tcm-MDP planar and SPET imaging, and for planar 67Ga-citrate imaging, there was no correlation with severity. We conclude that 67Ga-citrate SPET is able to identify vertebral osteomyelitis and detect additional sites of infection. It can also aid in determining the severity of infection and, potentially, the response to therapy.

Surgical treatment of cholangiocellular carcinoma

Cholangiocarcinoma is a primary liver tumor arising from the small bile ducts within the liver. According to its different location, clinical features, frequency of metastases, treatment modalities and prognosis, intrahepatic cholangiocarcinoma should well be differentiated from proximal bile duct carcinoma. To date, there is no therapeutic measure with curative potential apart from surgical treatment. Partial hepatectomy is the treatment of choice. It is of overriding importance to achieve microscopically tumor-free margins. However, only few patients treated in an early stage have a prolonged recurrence-free survival or a chance for cure. Liver transplantation is not an alternative therapeutic option for unresectable cholangiocarcinoma, due to early tumor recurrence in almost all recipients. Liver transplantation has a place in preventing cholangiocarcinoma in primary sclerosing cholangitis, although the timing of replacement is still a matter of debate. Results of surgery need further improvement by adjuvant or neoadjuvant treatment protocols.

Serous adenoma of the pancreas with multiple microcysts communicating with the pancreatic duct

The rare neoplastic cystic adenomas of the pancreas form two groups of tumors: macrocystic mucinous and microcystic serous adenomas. Both entities show specific radiologic and histologic features. Several recent case reports, however, suggest some diversity within the group of microcystic serous adenomas. We present the case of a young man operated because of epigastric pain for 12 months and a palpable microcystic tumor of the pancreatic head. Multiple cysts communicating with branches of the pancreatic duct in an alveolar-like pattern were demonstrated on endoscopic retrograde cholangiopancreatography. Histologic examination of the specimen confirmed the diagnosis of a serous adenoma of the pancreas. The tumor morphology in this case may suggest a ductal origin of microcystic serous adenomas.

MR imaging of mammographically detected clustered microcalcifications: is there any value?

PURPOSE

To assess the value of dynamic magnetic resonance (MR) imaging in patients with mammographically detected suspicious microcalcifications.

MATERIALS AND METHODS

Sixty-three patients (age range, 31-84 years; mean age, 56 years) with mammographically suspicious clustered microcalcifications underwent dynamic MR imaging of the breast before surgical biopsy. MR imaging was performed with a 1.5-T unit and a two-dimensional fast low-angle shot sequence with a flip angle of 80 degrees. Thirty-two axial sections, 4 mm thick and without interval gaps, were acquired before and five times after administration of gadopentetate dimeglumine (dose, 0.1 mmol per kilogram of bodyweight). Histologic findings were used as the standard of reference. Any effect of MR imaging on surgical management was noted.

RESULTS

Biopsy findings verified five patients with T1 invasive carcinomas, 33 with ductal carcinomas in situ, 13 with proliferative fibrocystic disease, eight with nonproliferative fibrocystic disease, and four with sclerosing adenosis. Contrast material-enhanced dynamic MR imaging had a sensitivity of 45%, a specificity of 72%, and an overall accuracy of 56% in differentiating benign from malignant microcalcifications. All invasive tumors were detected with MR imaging. In no case was surgical management altered by MR imaging findings.

CONCLUSION

MR imaging of the breast is not reliable in differentiation of benign from malignant breast disease in mammographically suspicious clustered microcalcifications and has no effect on treatment.

Storage phosphor direct magnification mammography in comparison with conventional screen-film mammography--a phantom study

Contact mammography with current photostimulable storage phosphors is hampered by its low spatial resolution. Detail visualization can be improved by geometric magnification radiography which enlarges small details to exceed inherent image noise. This study compares storage phosphor mammography using a dedicated direct magnification system with state-of-the-art conventional screen-film mammography. Storage phosphor direct magnification survey views (1.7x) and spot views (4x) were obtained with a prototype mammography unit providing focal spot sizes of 120-40 microns. Conventional technique screen-film survey views (1.1x) and spot views (1.8x) served as comparison. A contrast detail study and a receiver operating characteristic (ROC) analysis using an anthropomorphic breast phantom with superimposed microcalcifications was performed. Contrast detail resolution in the digital and conventional survey views were equivalent. For the spot views, contrast detail resolution was significantly higher with the digital technique (p < 0.001). ROC analysis of 400 observations demonstrated a significantly higher performance (p < 0.001) with digital images versus conventional screen-film mammograms. The area under the ROC curve (Az) in the digital survey views was 0.76 +/- 0.07 versus 0.59 +/- 0.02 in the conventional technique. In digital spot views, Az was 0.82 +/- 0.07 as compared with 0.66 +/- 0.04 in the conventional spot views. These results suggest that storage phosphor digital mammography in conjunction with direct geometric magnification technique may be superior to conventional screen-film mammography in the detection of microcalcifications.

[A new specimen radiography device with a maximum 20-fold magnification for breast diagnosis]

PURPOSE

A radiography system specially developed for specimen radiography and allowing maximal 20-fold magnification is presented. The efficiency of the system was tested and compared with that of conventional magnification mammography systems.

METHODS

23 surgical and 90 core biopsies of the breast were examined for detection of microcalcifications. As criteria the number of identifiable calcifications, their shape and configuration as well as tissue contrast were chosen.

RESULTS

The new technique detected about 400% more microcalcifications, 200% more core and 50% more surgical biopsies containing calcifications. Thus, in a few cases, additional core biopsies were unnecessary. Moreover, this new system yielded additional information for the pathologist and surgeon concerning the exact localisation of suspicious lesions that facilitated working up specimens, or indicated additional surgical removal in special cases.

CONCLUSIONS

By identification of malignant lesions not detectable with conventional magnification radiography systems, as well as a more exact localisation of suspicious lesions, false negative results may be reduced.

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.

Blurring of vessels in spiral CT angiography: effects of collimation width, pitch, viewing plane, and windowing in maximum intensity projection

PURPOSE

Our goal was to examine the effects of collimation width (CW), pitch, viewing plane, and windowing on the display of in-plane vessels in maximum intensity projection (MIP).

METHOD

A theoretical concept based on partial volume averaging of vessels was developed to describe the contents of voxels (densities) in MIP and to derive cross-sectional vessel diameters and blurring. To validate the concept and to describe the influence of pitch, a Plexiglas cone submerged in water was scanned with varying CW and pitch. Binary MIP with three representative window levels was chosen so that definitive vessel diameters could be quantitated.

RESULTS

The theoretical concept correctly predicted voxel contents and blurring for CW > or = 3 mm and low pitch. For high pitch, actual blurring was larger; however, for a given table speed, blurring of the cone decreased with pitch while increasing with CW. Overall blurring was most effectively reduced by using a thin CW and the transverse viewing plane. In the transverse viewing plane, the least blurring was found using binary MIP with a low window level. On the contrary, in the longitudinal viewing plane, blurring was minimized using a window level halfway between the density of the cone and that of the surrounding water.

CONCLUSION

For CW > or = 3 mm, blurring of in-plane vessels can be explained with a simple geometrical concept based on partial volume. For accurate display, the transverse viewing plane should be used, a proper windowing must be chosen, and the CW should be kept below vessel size while raising the pitch to cover a reasonable volume.

CT of retained surgical sponges (textilomas): pitfalls in detection and evaluation

PURPOSE

Our goal was to demonstrate possible pitfalls in the CT diagnosis of retained surgical sponges (textilomas) and to evaluate the impact of gas bubbles inside a textiloma.

METHOD

Thirteen patients with textilomas were investigated with CT 3 weeks to 8 years after surgery. Twelve of the 13 textilomas were removed within 3 weeks after the first CT examination. Eight samples of surgical sponges were placed in a water bath for 6 months. Serial CT was performed to document the presence and persistence of gas bubbles.

RESULTS

The radiopaque marker inside the textiloma was seen in nine patients but did not lead to the diagnosis in all patients. In seven patients gas bubbles were found inside the textiloma with a typical pattern. None of these patients had an abscess formation. In vitro studies demonstrated gas bubbles in all surgical sponges scanned 1 h afterward. The number of gas bubbles was not significantly reduced after 6 months.

CONCLUSION

The variable appearance of retained surgical sponges can lead to diagnostic misinterpretations. If present, typical spongiform pattern with gas bubbles is the most specific sign for the detection of textilomas but does not indicate an abscess formation.

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.

Must radiation dose for CT of the maxilla and mandible be higher than that for conventional panoramic radiography?

We evaluated the feasibility of performing preoperative spiral CT of the maxilla and mandible with a radiation dose similar to that used for conventional panoramic radiography. The skin entrance doses of radiation used for spiral CT (collimation, 1 mm; pitch, 2; tube voltage, 80 kV; tube current, 40 mA) and for panoramic radiography (75 kV, 8 mA, 15 seconds) were measured in one patient by using thermoluminescent dosimeter chips. Results were 0.56 +/- 0.06 mGy for CT and 0.59 +/- 0.04 mGy for radiography. Image quality was adequate for preoperative implant planning. Spiral CT of the mandible and maxilla may therefore be feasible with a radiation dose of similar magnitude as that used for conventional panoramic radiography.

MR arthrography in the diagnosis of rotator cuff tears. Standard spin-echo alone or with fat suppression?

PURPOSE

To examine the value of fat-suppressed images in MR arthrography of the shoulder in patients with rotator cuff tears.

MATERIAL AND METHODS

MR arthrography was performed in 25 patients (9 women, 16 men) ranging from 19 to 64 years. Standard T1-weighted spin-echo images (sSE) and fat-suppressed images (FS) were obtained after intraarticular injection of contrast material. The MR studies were analyzed according to contrast, image quality and conspicuity of pathology. A diagnosis was established without knowledge of the conventional arthrographic findings on the basis of sSE versus FS techniques.

RESULTS

The contrast between the intraarticular fluid and the adjacent structures in FS images was increased compared to sSE images in all patients. The conspicuity of anatomical structures was improved in 8 patients. Without fat suppression, 2 false-negative and one false-positive full-thickness tears were diagnosed. With the FS technique, 14 full-thickness tears and 4 partial-thickness tears of the cuff were correctly classified.

CONCLUSION

The results suggest that, if MR arthrography is chosen for a diagnosis of rotator cuff disorders, a fat suppression sequence should be included.

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.

Infrarenal abdominal aortic aneurysms: implications of CT evaluation of size and configuration for placement of endovascular aortic grafts

PURPOSE

To measure infrarenal abdominal aortic aneurysms and assess the implications and potential obstacles for placement of an endovascular aortic graft undergoing clinical testing in Europe.

MATERIALS AND METHODS

Helical computed tomography was used to measure 77 infrarenal aortic aneurysms (77 patients) and the distances between the aneurysms and the renal arteries and the aortic bifurcation.

RESULTS

Mean length of the aneurysms was 8.2 cm; mean distance to the renal arteries, 2.7 cm; mean aortic diameter 1.5 cm distal to the renal arteries, 1.9 cm; and mean minimal diameter of perfused lumen, 2.5 cm. Thirteen aneurysms extended into the common iliac artery; 40 reached the bifurcation. The mean minimal luminal diameter of the iliac artery was 1.1 cm.

CONCLUSION

Sufficient nonaneurysmal segments below the renal arteries and distal to the aneurysms are necessary for stent fixation. The large diameter of the delivery introducer in relation to the iliac arteries may be a major obstacle to graft delivery. At best, 33 patients could have benefited from use of the graft evaluated.

MR imaging-guided breast intervention: experience with two systems

PURPOSE

To evaluate two different systems for magnetic resonance (MR) imaging-guided breast intervention.

MATERIALS AND METHODS

Thirty-four patients with 34 lesions detected exclusively with contrast material-enhanced MR imaging underwent 51 interventional procedures (23 needle biopsies and 28 preoperative wire localizations) with two different systems. An add-on device for surface coils was used in 25 cases, and a dedicated single breast biopsy coil was used in 26. For needle biopsies, material was aspirated with nonmagnetic 19.5-gauge needles. For preoperative localizations, nonmagnetic hook wires were used.

RESULTS

Surgical excision or follow-up verified the cytologic findings in 19 of the 23 cases sampled for biopsy. Cytologic diagnosis was impossible in three of the 23 cases. One technical failure occurred with the biopsy coil. Open biopsy performed after MR imaging-guided localization successfully removed 26 of the 28 lesions. One missed carcinoma was found at repeat localization and removed. One technical failure occurred with the biopsy coil. In that case, the lesion was close to the chest wall.

CONCLUSION

Both systems are suitable for fine-needle biopsy and preoperative localization of lesions seen exclusively on MR images.

Helical CT of the liver: evaluation of injection flow rate, mode, and scan delay with a reduced-volume contrast medium bolus

OBJECTIVE

The impact of injection flow rates, mono- or biphasic injection mode, and scan delay on liver and portal vein enhancement with helical CT was evaluated.

MATERIALS AND METHODS

The liver of 75 consecutive patients was examined with helical CT before and after injection of 100 ml iopromide (30 g of iodine). Patients were randomly assigned to three protocols: (1) injection flow: 2 ml/s; (2) injection flow; 4 ml/s (60 ml) + 2 ml/s (40 ml); and (3) injection flow: 4 ml/s. Scanning started 40 s after the beginning of contrast material injection. A second scan was performed 70 s after contrast agent injection in Protocol 1.

RESULTS

Mean parenchymal contrast enhancement was highest with Protocol 3 (48.5 HU) followed by Protocols 2 (38.9 HU) and 1 (early: 21 HU; late: 30.7 HU), with all differences being significant (p < 0.01). Enhancement of the portal vein was significantly higher with Protocols 3 and 2 (121 and 118 HU) than with Protocol 1 (early: 64 HU; late: 75 HU).

CONCLUSION

Good enhancement of the liver parenchyma and the portal vessels can be obtained with 30 g of iodine if a monophasic injection with a flow rate of 4 ml/s is used.

True aneurysm of the superior gluteal artery: case report and review of the literature

Aneurysms of the gluteal arteries are rare and mostly are caused by pelvic fractures or penetrating injuries. As such these aneurysms are pseudoaneurysms. As an absolute rarity we report the case of a 43-year-old man with a histologically verified 5 cm-diameter, true saccular aneurysm of the left superior gluteal artery. The patient was admitted with 6-weeks ongoing sciatic pain without previous trauma. He was scheduled for surgery because an initial attempt of transcatheter embolization failed. By dividing the origin of the gluteus maximus muscle from the iliac crest, the aneurysm was exposed at the pelvic outlet by an extrapelvic approach and was excluded by endoaneurysmorrhaphy. Uncontrolled bleeding was prevented by temporary occlusion of the left iliac artery by a percutaneously inserted balloon catheter, thus avoiding an additional retroperitoneal approach. The postoperative course was uneventful, and sciatic pain had resolved completely. The chosen strategy provides safe and successful surgical management of gluteal artery aneurysms.

Parenchymal liver enhancement with bolus-triggered helical CT: preliminary clinical results

A software-driven device for bolus-triggered start of helical computed tomography (CT) was evaluated in liver studies of 30 patients with suspected metastatic liver disease. Compared with results in a control group of 30 patients who underwent conventional contrast material-enhanced helical CT, the study group had significantly higher and more constant parenchymal enhancement (P < .05, Mann-Whitney U test). This technique helps optimize findings at contrast-enhanced helical CT.

MR-guided localization of suspected breast lesions detected exclusively by postcontrast MRI

OBJECTIVE

We describe and evaluate a preoperative MRI localization procedure for suspected breast lesions.

MATERIALS AND METHODS

Fourteen consecutive patients underwent MR localization of suspected breast lesions discovered with contrast-enhanced MRI but not detected by conventional mammography or ultrasound. In each case diagnostic MRI was repeated after the application of special skin markers. A non-magnetic wire was subsequently inserted into the breast and a second MRI performed to document the position of the wire tip relative to the lesion.

RESULTS

The procedure was successful in all 14 patients, enabling excision of the lesion and allowing histological diagnoses.

CONCLUSION

We found the described procedure to be quite useful.

Broadband ultrasound attenuation in the diagnosis of osteoporosis: correlation with osteodensitometry and fracture

PURPOSE

To evaluate the usefulness of broadband ultrasound attenuation in the prediction of osteoporosis.

MATERIALS AND METHODS

Broadband ultrasound attenuation measurements of the calcaneus and dual x-ray absorptiometry (DXA) measurements of the lumbar spine and the femoral neck were obtained in 400 patients (295 female and 105 male), 135 of whom were classified as having osteoporosis. Correlation coefficients between broadband ultrasound attenuation and DXA were calculated.

RESULTS

Patients with osteoporosis showed a statistically significant decrease in broadband ultrasound attenuation compared with healthy patients (59.7 dB/MHz +/- 1.3 [standard deviation] vs 75.1 dB/MHz +/- 0.8). Broadband ultrasound attenuation correlated statistically significantly with vertebral bone density (r = .49) and femoral neck density (r = .52). At a broadband ultrasound attenuation index of 64 dB/MHz, the sensitivity and specificity were both 85% for patients with osteoporotic fractures.

CONCLUSION

Broadband ultrasound attenuation can be used to help differentiate between patients with osteoporosis and healthy patients and seems to be useful in the prediction of fracture risk.

Optimization of chest films of equalization radiography (advanced multiple beam equalization radiography). Comparison by means of a receiver operating characteristic study of simulated nodular interstitial disease

RATIONALE AND OBJECTIVE

To optimize screen-film combinations for equalization radiography (advanced multiple beam equalization radiography [AMBER]), five different film-screen-technique combinations were compared by receiver operating characteristics study of simulated interstitial disease.

MATERIALS AND METHODS

The Ortho C-Lanex Regular and the Insight Thoracic Imaging HC system were compared in conventional nonequalized technique; T-Mat G-Lanex Regular and T-Max L-Lanex Regular were compared in conventional, nonequalized, and AMBER technique; and an experimental high-contrast, low-noise, near-zero crossover film-screen combination was compared in AMBER technique. Interstitial disease was simulated by superimposing birdseed on the back of a humanoid phantom. Twenty-five posterior-anterior radiographs were made with each technique. Seven observers scored the presence of interstitial disease in each of the quadrants on a 5-point scale following receiver operating characteristic methodology.

RESULTS

The highest performance was found with the experimental film-screen-AMBER combination (Az = 0.92) and the lowest with the T-Mat L-Lanex Regular-AMBER combination (Az = 0.83) and the Insight Thoracic Imaging HC system-conventional combination (Az = 0.85). T-Mat L-Lanex Regular-conventional ranked second (Az = 0.90) while T-Mat G-Lanex Regular-conventional (Az = 0.89), T-Mat L-Lanex Regular-AMBER (Az = 0.88) and Ortho-C-Lanex Regular-conventional (Az = 0.87) scored lower.

CONCLUSION

Higher contrast films in AMBER improve diagnostic performance, whereas a loss of information is found if the AMBER system is combined with lower contrast films.

Dissection of the thoracic aorta: pre- and postoperative findings on turbo-FLASH MR images obtained in the plane of the aortic arch

This pictorial essay illustrates the pre- and postoperative findings seen in patients with aortic dissections on contrast-enhanced turbo-fast low-angle shot (FLASH) MR images obtained in the plane of the aortic arch. Contrast-enhanced images provide morphologic and functional information not normally available with conventional spin-echo (SE) MR imaging or dynamic CT. Preoperative examination of the acute dissection is often troubled by cardiovascular insufficiency and motion artifacts. Therefore most of our patients were examined postoperatively. The main reason for postsurgical imaging is the evaluation of the flow in the different lumina and the detection of complications (i.e., aneurysms or progress of dissection).

[Inflammatory lesions of the breast: indication for MR-mammography?]

In a retrospective study the value of MR imaging of the breast in inflammatory changes was evaluated. The signal enhancement of 8 patients with histopathologically verified inflammatory carcinomas and 9 patients with global mastitis as well as local inflamed lesions was analysed. Neither signal behaviour nor signal/time relation were suitable to differentiate between malignant and benign changes. In conclusion inflammatory changes of the female breast are not indicated to be examined with MR imaging.

MR-guided biopsy of suspect breast lesions with a simple stereotaxic add-on-device for surface coils

A guiding attachment is described that transforms a conventional magnetic resonance (MR) imaging surface coil into a stereotaxic biopsy unit. Eight patients, aged 38-66 years (mean, 54 years), with suspect breast lesions detected exclusively at contrast material-enhanced MR imaging underwent MR-guided needle biopsy with this unit. Diagnostic material was successfully aspirated in all patients (four carcinomas, three fibroadenomas, and one intraductal hyperplasia), and the diagnosis was subsequently confirmed at surgical biopsy. This technique promises to increase the diagnostic specificity for lesions seen solely at MR imaging.

Superimposed peripheral pulmonary vasculature in anthropomorphic chest phantoms

RATIONALE AND OBJECTIVES

Comparative radiologic studies often involve the use of phantoms. However, in most chest phantoms, the lack of sufficient peripheral vessels results in unrealistic images. This can impair the reliability of conclusions drawn from the studies performed. The authors present a method of improving the simulation of the peripheral pulmonary vasculature in anthropomorphic chest phantoms.

METHODS

The appearance of peripheral vessels was simulated using red lead painted on transparent foils. Several of the foils were taped to the back of the phantom to give the impression of superimposed blood vessels.

RESULTS

Subjectively, a more realistic appearance of peripheral vasculature was obtained in the radiograph.

CONCLUSIONS

Our method improves the quality of widely available anthropomorphic chest phantoms, and the modification is easily implemented. However, the use of lead limits the modified phantom to comparative studies with constant exposure voltage.

Application of AMBER in single- and dual-energy digital imaging: improvement in noise level and display dynamic range

The combination of computed radiography (CR) and advanced multiple beam equalization radiography (AMBER) was evaluated for both single- and dual-energy chest radiography. The improved signal-to-noise ratio found with CR and AMBER resulted in a better visualization of structures in the mediastinum and basal lung than that found with CR alone. For the central lung, no improvement was seen. Because of the compressed dynamic range with CR and AMBER, contrast on hard copies and video monitors could be high without a sacrifice in image latitude. Dual-energy images showed a considerably lower noise level. The combined use of AMBER and CR promises to overcome the dynamic range limitations of digital displays while improving signal-to-noise ratio.

Scanning equalization mammography: preliminary evaluation

The authors show preliminary work with an experimental scanning equalization mammography system intended to increase contrast and achieve adequate dose throughout the breast. The unit uses a modulated, segmented fan beam. Tests with and without scanning equalization were performed with contrast-latitude phantoms and a breast specimen with superimposed microcalcifications. Films of varying contrast were evaluated. Contrast at low and very high object densities was greatly improved with the equalization technique. Microcalcifications were better appreciated, especially in those regions of the specimen that were outside the optimal optical density range of the conventional technique.