[The percutaneous transarterial embolization therapy of traumatic kidney hemorrhages]

PURPOSE

To demonstrate the possibility of transarterial, superselective embolization after traumatic kidney injury and hemorrhage in patients usually treated by surgery.

METHODS

In a series of 16 patients aged 21 to 86 years (mean 37 years) external trauma led to kidney damage and consecutive bleeding. After diagnostic angiography (5 F) the exact site of hemorrhage was detected and treated by superselective embolization via a coaxial catheter system (2.7 F) either by coils (n = 5) or liquid agents (ethibloc, n = 11).

RESULTS

In all patients bleeding was stopped interventionally. Additional surgical treatment was not necessary in any case. In one older patient with preinterventionally known reduced kidney function, the excretion function decreased to creatinine levels of about 3.6 mg/dl after therapy and led to compensated nephric insufficiency. Other complications were not observed.

CONCLUSION

Interventional embolization is a well-tolerated and effective treatment modality after traumatic kidney hemorrhage. After exclusion of other injuries obligate for surgery, percutaneous transarterial therapy may help to avoid an operation. This reduces the risk of narcosis and treatment especially in multimorbid patients.

[Diagnosis of gallstone ileus]

Gallstone ileus is a rare disorder, which, because it is often misdiagnosed preoperatively, may become life-threatening. The classic triad of Rigler (aerobilia, small bowel ileus and a calcified, dystopic stone) is visualized on abdominal plain films in only 14-35% of cases. Further work-up includes ultrasound, upper gastrointestinal series with water soluble contrast medium and computed tomography (CT). CT is especially reliable in demonstrating all three criteria.

Diagnostic value of spiral-CT angiography in comparison with digital subtraction angiography before and after peripheral vascular intervention

To evaluate spiral-computed tomography (CT) angiography in primary diagnosis and/or in noninvasive follow-up after vascular intervention, we compared spiral-CT angiography and conventional angiography before and after vascular intervention. Helical-CT examinations before and after percutaneous transluminal angioplasty (PTA) or stent implantation were performed in 10 patients (mean age 63 years) with symptomatic peripheral arteriosclerotic disease. Stenoses were located in the iliac, femoral, or popliteal artery. CT examinations were done with a spiral-CT in double detector technique (CT Twin, Elscint). The parameters were as follows: slice thickness: 5.5 mm, increment: 2.7 mm, pitch: 1.5, contrast medium: 150 mL, flow rate: 2.5 mL/second, delay: 30 seconds. For evaluation, transverse planes as well as maximum intensity projections and 3-D reconstructions were used. The possible scan length reached from the aortic bifurcation down to about 10 cm below the ankle trifurcation. Preinterventional digital subtraction angiography (DSA) was superior to CT angiography (CTA: 94%, maximum intensity projection [MIP] alone: 65%), although high-grade stenoses were detected by both methods. After intervention, a resolved stenosis and improved peripheral flow could be detected by helical-CT as well as by intraarterial angiography in every patient (100%). In the primary diagnosis of vascular changes, intraarterial DSA remains the method of choice. Nevertheless, spiral-CT angiography shows comparable results after percutaneous intervention and becomes a noninvasive alternative in the postinterventional follow-up.

Virtual cystoscopy based on helical CT scan datasets: perspectives and limitations

The purpose of the study was to simulate cystoscopy based on three-dimensional helical CT scan datasets in real-time in patients with tumours of the urinary bladder. A helical CT scan with double detector technology was carried out pre-operatively in 11 patients with histologically confirmed carcinoma of the urinary bladder and one patient with chronic cystitis. A non-enhanced scan was first performed, followed by an examination in the early phase of contrast medium enhancement. Further images were acquired after adequate filling of the bladder with contrast medium, approximately 30 min after injection. These data were transferred to a separate graphic computer workstation and reconstructed. The results were then compared with the cystoscopic and histopathological findings. All tumours of the urinary bladder identified at fibreoptic cystoscopy were shown on virtual cystoscopy. The best reconstruction results were obtained from data acquired 30 min after injection of contrast medium. The ureteric orifices were not visualized at virtual cystoscopy. These data lead us to conclude that, at present, virtual cystoscopy has not reached the quality of fibreoptic examination and remains restricted to use in specific cases, for example patients with urethral strictures.

The average dose-area product at intravenous urography in 205 adults

The intravenous urography (IVU) is the most important and most frequently performed radiological examination in urology. This prospective study determined the dose-area product as a measurement of radiation dose in 205 adult patients undergoing IVU. Average dose-area product was 1017 cGy cm2. An average 3.7 radiographs were obtained per patient. Tomographic views were required in only 8.8% of cases. Radiation dose is dependent not only on the number and size of the obtained radiographs, but on the physical constitution of the patient. The dose-area products measured show a clear relationship to the body weight of the patient.

[MRI of the abdomen combined with enteroclysis in Crohn disease using oral and intravenous Gd-DTPA]

In spite of the improved MR-diagnosis of the abdomen, MRI is not used as a routine method for the diagnosis of inflammatory small bowel disease. The aim of this study was--after optimazation of the bowel opacification--the correlation of the findings obtained with enteroclysis and MRI in patients with known Crohns' disease. 60 patients between 17 and 72 years of age were investigated. First, an enteroclysis was performed in typical manner. The applicated methylcellulosis was blended with positive oral MR contrast media (Magnevist oral, Schering). After enteroclysis, MRI of the abdomen was performed using T1- and T2-weighted breathhold sequences (Flash 2D pre- and postcontrast and TSE) in axial and coronal planes. The length of the affected bowel and the stenosis seen with enteroclysis correlated well with the visible thickening of the small bowel wall and the stenosis seen in MRI. Using MRI, additional findings could be obtained in 28 patients, such as fistulas, abscesses or a hydronephrosis, or a better assessment of the stenosis was possible with MRI, because of the avoidance of overshadowing of the affected bowel loop with MRI. A brilliant MR-tomographic imaging of the small bowel is possible under the condition, that the small bowel contrast is optimal. The main prerequisite is a large filling volume of the small bowel to reach a homogeneous contrast and a good distension of the small bowel lumen.

MRI follow-up of pisiform bone transposition for treatment of lunatomalacia

OBJECTIVE

Transposition of the pisiform bone is an operative treatment for lunatomalacia. The postoperative viability of the transposed pisiform bone is difficult to assess. The purpose of the study was to evaluate the utility of MRI for postoperative assessment of viability of the pisiform and lunate bones.

DESIGN AND PATIENTS

Six patients who underwent transposition of the pisiform for treatment of lunatomalacia, were assessed pre- and postoperatively with conventional radiographs (including tomography), CT and MRI.

RESULTS

Conventional radiographs, conventional tomograms and CT were all useful in demonstrating the location of the transposed pisiform. CT showed the transposed pisiform without superposition. However, neither CT nor conventional techniques provided information regarding viability of the pisiform. In all patients investigated in the first year following surgery, T1-weighted MR images showed high signal intensity in the transposed bones. In all patients investigated after 1 year, the signal intensity decreased to an intermediate level on T1-weighted images. Enhancement following contrast medium administration in the transposed pisiform and the lunate was noted in all patients, indicative of viability.

CONCLUSION

Contrast-enhanced MRI is able to provide important information regarding the viability of the transposed pisiform and the remaining parts of the lunate. Thus, contrast-enhanced MRI provides an improved means of postoperative assessment regarding short-term follow-up following pisiform transposition. In the long-term follow-up conventional radiography and CT may be equal to MRI in showing increasing sclerosis and/or fragmentation.

Comparison of real-time virtual and fiberoptic bronchoscopy in patients with bronchial carcinoma: opportunities and limitations

OBJECTIVE

Both helical CT and fiberoptic bronchoscopy are used in the staging of pulmonary tumors for therapeutic decision making. The improved resolution offered by helical CT has led to the clinical use of three-dimensional reconstruction techniques such as virtual bronchoscopy. We tested this new simulated endoscopic view of inner organ surfaces and compared it with corresponding fiberoptic examinations of the tracheobronchial system.

SUBJECTS AND METHODS

Twenty patients with malignancies of the lung and mediastinum were examined with both virtual bronchoscopy and fiberoptic bronchoscopy. Both examinations were reviewed by radiologists and surgeons familiar with fiberoptic bronchoscopy. Virtual bronchoscopy was calculated and reconstructed from the cross-sectional images on a separate workstation. Stenoses and tumor infiltration were classified from the fiberoptic examination. These results were compared with the virtual bronchoscopy findings.

RESULTS

Virtual bronchoscopy of diagnostic quality was achieved in 19 of 20 patients. High-grade stenoses were revealed equally well with virtual and fiberoptic techniques. Virtual bronchoscopy offered the advantage of being able to visualize areas beyond even high-grade stenoses. However, on virtual bronchoscopy discrete infiltration or extraluminal impression was not visible in five patients. In another patient, strong heart pulsation produced motion artifacts that prevented evaluation of the reconstruction.

CONCLUSION

Virtual bronchoscopy represents a new noninvasive method for evaluating helical CT findings. In comparison with fiberoptic bronchoscopy, virtual bronchoscopy offers the advantage of being able to visualize areas beyond even high-grade stenoses. In addition to the limited view of fiberoptic bronchoscopy, extraluminal causes of lumen compressions can be analyzed in the cross-sectional images and evaluated together with the virtual representation. However, it was not possible to detect small infiltrations with virtual bronchoscopy. This new representation of helical CT data might be helpful for postoperative follow-up examinations, such as after stent implantation, and can be carried out without additional risk to the patient. Radiologists do need special fiberoptic bronchoscopy knowledge and experience with three-dimensional-reconstructions to differentiate between real stenoses and artificial stenoses that might be caused by pulsation artifacts.

Displaced metallic biliary stents: technique and rationale for interventional radiologic retrieval

OBJECTIVE

We investigated the spontaneous course and the possibility of transhepatic removal of displaced biliary stents.

MATERIALS AND METHODS

Displaced biliary stents were observed in 11 patients (13-75 years old) between October 1988 and August 1996. Stent types included the Palmaz stent (n = 3), Wallstent (n = 3), and the Strecker stent (n = 5). Reasons for stent displacement included primary misplacement (n = 4), dislocation due to transhepatic endoscopy with biopsy (n = 2), dislocation resulting from a recanalization maneuver in stent occlusion (n = 3), and unknown causes (n = 2). In three cases, the stent was displaced into the proximal bile duct system. Seven patients had primary malignancy.

RESULTS

Eight of 11 displaced biliary stents were removed transhepatically. Extraction was performed using either a wire loop (n = 4) or forceps (n = 4). No complications occurred. In the remaining three patients, whose stents were displaced into the intestine, no invasive action was taken. In one of these patients, a Palmaz stent was passed spontaneously after 1 week. In the second of these patients, a 6 cm Wallstent remained innocuously at a position in the right lower abdomen, and the patient died as a result of malignancy. In the third patient, who had a 10-cm Wallstent, an abscess developed in the stent region 4 months after displacement and resulted in formation of an ileocutaneous fistula.

CONCLUSION

Transhepatic extraction of displaced biliary stents is technically possible, even in the case of rigid stents such as the Palmaz stent. Because of the risk of intestinal perforation, displaced stents should be removed.

[MR enteroclysis for nuclear spin tomographic diagnosis of inflammatory bowel diseases with contrast enhancement]

PURPOSE

To evaluate MRI for effectiveness in assessment of intra- and extramural changes in the small intestine.

METHODS

40 patients with known or suspected small bowel disease underwent MR imaging immediately after conventional enteroclysis with barium and a mixture of methyl cellulose and gadolinium-DTPA.

RESULTS

In 6 of 24 patients with no pathological findings in conventional enteroclysis, intraabdominal pathology such as thickening of the intestinal wall and an abscess were identified. In the remaining patients, MRI showed good correlation with conventionally obtained data and provided important additional information regarding extraluminal involvement such as enlargement of mesenterial lymph nodes and fistulas as well as abscesses.

CONCLUSIONS

MRI, carried out using this technique, provides important additional information regarding intra- and extraluminal changes with good image quality.

Sensitivity of computed tomography in detecting local recurrence of prostatic carcinoma following radical prostatectomy

The aim of this study was to evaluate CT imaging in the post-operative follow-up and in the detection of recurrence after radical prostatectomy in cases of prostatic carcinoma. In over 500 patients undergoing radical prostatectomy for prostatic carcinoma, 22 cases with local recurrence were found. CT examinations of the pelvis were retrospectively evaluated in these patients. Local recurrence was detected by PSA uptake and confirmed by transrectal ultrasound (TRUS) in combination with guided biopsy. In 22 cases of confirmed local recurrence, positive results on CT were found in eight patients (36%) and negative results in nine patients (41%). In the remaining five cases (23%), no distinction could be made between scar and local recurrence. All cases definitively classified as recurrent tumour disease showed a soft tissue mass of 2 cm or more. CT sensitivity in local recurrence of prostatic carcinoma after surgery is low. Even in a very careful follow-up, the understaging would be up to 41%. In comparison, PSA, TRUS and needle biopsy are the methods of choice and are superior to CT imaging. Based on these results, there would be no reason for including pelvic CT examinations in the follow-up of prostatic carcinoma after radical prostatectomy.

[Radiation exposure in digital micturition cystourethrography in children. How much exposure by fluoroscopy?]

OBJECTIVE

Determination of the proportion of the dose-area product caused by fluoroscopy at voiding cystourethrography in children, using digital image intensifier technology.

PATIENTS AND METHODS

Using computer-assisted dosimetry, we determined the dose-area product and the respective proportions of the dose-area product caused by fluoroscopy and radiography as well as the number of radiographs taken at a given examination of 40 children (8 children less than 2 years old, 15 children between 2 and 6 years old and 17 children between 6 and 15 years old).

RESULTS

The computer software program correctly differentiated between fluoroscopy and radiography in 80% of cases. Incorrect results were primarily observed in newborns and young children. The total radiation dose ranged in relation to patient age from 22 to 651 cGy x cm2. Fluoroscopy was responsible for an average 78% of the applied radiation dose.

CONCLUSION

Computer-assisted dosimetry is useful in determining the proportion of the dose-area product caused by fluoroscopy in older children undergoing voiding cystourethrography. When image intensifier technology is used, this accounts for more than 75% of the total radiation dose. The method is not suitable for use in small children.

[The diuresis urogram in patients with a bladder replacement]

PURPOSE

To differentiate between urodynamically relevant obstruction and functionally unimportant dilation of the upper urinary tract in patients with neobladder using a modified furosemide urogram.

METHOD

An excretory urogram with furosemide loading was carried out in 19 patients with neobladder and sonographically and urographically confirmed dilation of the upper urinary tract. Once strong contrasting of the renal pelves and calyces has been achieved, 20 mg of furosemide were applied and late radiographs were obtained at 15 min and 30 min, respectively. An obstruction was defined as increasing dilation of the renal pelves and calices during forced diuresis and lack of washout effect of the contrast medium.

RESULTS

In 32 cases, the renoureteral unit (RUU) was dilated on ultrasound. Of these, 25 RUU's showed good emptiness of contrast medium upon stimulation of diuresis, six RUU's returned a borderline findings, while one RUU was found to exhibit a decompensated anastomotic stenosis, which was dilated. Two further patients with borderline findings were later treated surgically due to their pain symptoms. No patient required further preoperative diagnostic procedures.

CONCLUSIONS

The modified furosemide urogram represents a cost-effective diagnostic orientation strategy in patients with neobladder and dilated renal pelves and calyces and is both well-tolerated by patients and meets with broad acceptance from the urologic staff.

Computer assisted determination of the dose-area product in retrograde urethrography

Retrograde urethrography (RUG) is a dynamic radiological procedure in which the cumulative dose-area product (DAP) comprises radiation doses derived from both fluoroscopy and radiography. In the present prospective study, digital retrograde urethrographs (Prestilix 1600X/DRS, General Electric) were obtained in 40 consecutive male patients (mean age 60.6 years; range 23-88 years) presenting for evaluation of urinary pathology. The radiation dose was recorded as the dose-area product. From these data, a computer program (Diasoft 2.0, PTW, Freiburg, Germany) then determined the respective proportions of the total radiation dose deriving from fluoroscopy and radiography, as well as the number of radiographic exposures. The average total radiation dose was 316 cGy cm2. In five of the 40 patients examined (12.5%), the number of radiographic exposures registered by the program and, hence, the calculated DAPs were erroneous. In the remaining 35 patients, the average proportion of the cumulative DAP resulting from fluoroscopy was 81%, while that deriving from radiography was 19%. The computer program utilized in this study makes possible an intelligent evaluation of the DAP in dynamic procedures such as RUG. Since fluoroscopy is responsible for 81% of the cumulative DAP at RUG, a significant decrease in applied radiation dose may be achieved by reducing fluoroscopy time or by using pulsed fluoroscopy.