[Characterization and staging of renal tumors: significance of MRI diagnostics]. / Charakterisierung und Staging von Nierentumoren: Bedeutung der MRT-Diagnostik.

PURPOSE: Retrospective evaluation of MRI in the diagnosis of renal masses and determination of the correlation of MRI with histology or follow-up. MATERIALS AND METHODS: 46 consecutive patients (13 female, 33 male, mean age 64.7 yrs) with suspected renal tumors were examined with a 1.5 T MR scanner using a standardized protocol (TSE T2fs, 2DGRE T1, dynam. ce3DGRE T1fs, ce2DGRE T1fs, ce3DGRE urogram). RESULTS: 142 renal lesions were found with diameters of < 2 cm up to 14 x 18 cm. A primary classification as solid and cystic lesions was performed according to MRI criteria. In 29 cases we found lesions bilaterally, in 17 patients only in one kidney, and in four cases we found multifocal renal tumors unilaterally (n = 3) or bilaterally (n = 1). In 22 patients with renal tumors, cystic lesions could be seen as well. In 19 cases these were uncomplicated cysts, and in 3 cases these were complicated cysts. 35/43 lesions were histologically proven solid vascularized tumors (29 renal cell carcinomas, 6 urothelial carcinomas), five additional masses with tumor signs in MRI appeared to be progressive during follow-up thus suggesting malignancy, and one case was a multifocal bilateral renal tumor. 3/43 lesions were initially reported as being suspected of malignancy but were proven during follow-up or histologically to be benign. Tumor thrombus was depicted in MRI in the renal vein in 5 cases, stretching into the IVC in 4 cases and proven histologically in 4 and 3 cases, respectively. Of these solid masses, 99 cystic lesions could be differentiated clearly in MRI (88 simple cysts, 11 complicated cysts) that remained unchanged during follow-up (6 - 65 months) or were proven to be cysts histologically. In 17 cases these cysts were bilateral, in 19 cases unilateral, and 33 kidneys showed multicystic changes. In characterizing renal masses, MRI showed a positive predictive value of 93 % for the diagnosis of a malignant tumor. The T-stage of histologically proven renal cell carcinomas using MRI was correct in 89 %. CONCLUSIONS: MRI is a valid modality for characterizing and staging renal masses using a suitable sequence protocol that includes dynamic ce studies. Venous tumor invasion can be depicted safely. MRI can be employed alternatively to state-of-the-art ceCT and additionally to CT in unclear cases.

Pre-interventional prognostic value of renal endocrine, hemodynamic and arteriographic parameters in hypertensive patients with uni- and bilateral renal artery stenosis: a ten years' experience.

In order to improve pre-interventional prognosis of blood pressure normalization, in patients normalization, in patients with angiographically proven uni- (n = 75) and bilateral (n = 38) renal artery stenosis, (RAS) evaluation of renal venous and peripheral renin activity including stimulative procedures and Saralasin-infusion-test was carried out. In addition selective renal arteriographic, hemodynamic and pharmacodynamic (133 xe-washout) investigations were performed. The data were correlated with operative results concerning response of blood pressure to surgical treatment in 54 patients with uni- and 30 patients with bilateral RAS. Our results suggest that a postoperative normalization of blood pressure can only be expected if pre-interventional selective arteriograms reveal a normal vascular tree accompanied with normal cortical flow rates of both kidneys in uni- and bilateral RAS. Selective renin determinations, stimulative procedures of the renin-angiotensin system and application of angiotensin antagonists are only of value for selection of patients.

Anomalous intrapulmonal vein drainage and pulmonary vein connection in DSA.

Anomalous pulmonary venous drainage can be detected and evaluated by angiographic studies. Now that intravenous DSA is available, this method can be used to demonstrate pulmonary venous return. This study presents the results of DSA examination in three patients having anomalous pulmonary vein connection with the left innominate vein and the superior vena cava respectively. In a fourth patient, intra-pulmonary atypical venous return could be demonstrated by DSA without anomalous connection. This minimal invasive procedure is diagnostically useful in anomalies of pulmonary veins when recommended post-processing techniques are evaluated, particularly in patients with additional cardiac septal defects.

Transvenous digital subtraction angiography (DSA) for diagnostic control following percutaneous transluminal angioplasty (PTA) in patients with renovascular hypertension.

Transvenous digital subtraction angiography (DSA) of the kidneys has shown to be useful in detection of renovascular abnormalities in hypertensive patients. In this study DSA was performed in 27 patients (fibrom. dyspl. n = 12, arterioscl. n = 15) following percutaneous transluminal angioplasty (PTA) of renal artery stenosis. Concerning PTA-effect on blood pressure, patients were classified in 3 groups (normal n = 13, improved n = 10, failure n = 4). DSA images and simultaneously determined effective renal plasma flow (ERPF) were correlated with response of blood pressure to PTA. The results demonstrate the usefulness and accuracy of transvenous renal DSA-imaging in follow-up studies. Normal ERPF correlated with a completely re-opened renal artery and normal renal parenchyma in DSA in normotensive patients. In patients with persistent or recurrent hypertension (n = 14) ERPF was reduced in 10 cases and DSA demonstrated disorders such as peripheral renal infarction or reduced renal size (n = 6) and re-stenosis (n = 2).

[Venous digital subtraction angiography of the kidneys in the diagnosis of hypertension]. / Venöse digitale Subtraktionsangiographie der Nieren in der Hypertoniediagnostik.

Intravenous DSA plays an important role in screening of hypertensive patients for renovascular disease. A preselected hypertensive outpatient group (n = 55) was studied by DSA. For renal arteries a valuable visualization was 93% (102/110) using one (62%) over two (25%) to three (13%) sequences. Perihilar segmental arteries could be analyzed in 56% of cases. Using replay (off-line) in DSA, renal size and parenchymal contours could be evaluated following a sequence-period of about 20 seconds. A pyelographic image completes this renal diagnostic procedure in hypertensive patients.

[Balloon catheter dilatation in the treatment of the subclavian steal syndrome]. / Ballonkatheterdilatation in der Behandlung des Subclavian-Steal-Syndroms.

The present paper reports on the results of PTA in the treatment of subclavian steal syndrome and significant proximal subclavian artery stenosis in thirteen patients. In all cases, it was possible to dilate the stenoses successfully and without complications. Cerebral symptoms caused by the steal phenomenon (seven patients) were relieved in all cases and ischaemic symptoms in the arms produced by exercise were cured in ten out of eleven patients. Balloon catheter dilation of proximal subclavian stenosis in symptomatic patients is the treatment of choice, as judged by our own experience and the data in the literature.

[Mesentericography: role of intra-arterial DSA in acute occlusive disease]. / Mesenterikographie: Rolle der intraarteriellen DSA bei akuter Verschlusskrankheit.

This study was carried out to evaluate the intra-arterial DSA method for diagnosis of occlusions of the mesenteric vessels. DSA examination in 24 patients (sup. mes. a.n = 24, inf. mes. a.n = 2) demonstrated that image quality was diagnostic in 84%, i.e. contrasting of mesenteric artery including the peripheral branches, when 10 ml of the contrast medium was injected selectively. In 63% of examinations the mesenteric venous return could be documented. Causes of DSA failure were image artefacts due to reduced patient's cooperation and bowel motion. Otherwise the obvious advantage of i.a. DSA was an immediate diagnostic imaging in patients with severe occlusive vascular disease using a manual administration of only small volumes of contrast material.

[Intravenous digital subtraction angiography for imaging pulmonary vessels]. / Die intravenöse digitale Subtraktionsangiographie (DSA) zur Darstellung der Pulmonalgefässe.

The experience in venous digital subtraction angiography (DSA) of the pulmonary vessels is presented in order to evaluate the new method. The results of angiographic examinations in 30 patients could be classified as follows: embolic lung disease (n = 13), atelectatic disease of left lower lobe (n = 3), findings of arteritis in right upper lobe (n = 1), arteriographic alterations due to chronic pulmonary emphysema (n = 2), normal lung vessels (n = 10), and failure of examination (n = 1). Using this new angiographic method it was possible to analyze embolic clots in the subsegmental arteries and total occlusions of the peripheral small vessels. The advantage of DSA compared with the conventional technique is evident: No complications due to transcardial catheters, short examination period, easy handling of the technique, and small number of images.

[Importance of transvenous digital subtraction angiography (DSA) in detecting vascular complications following aorto-iliac/femoral bifurcation bypass]. / Bedeutung der transvenösen digitalen Subtraktionsangiographie (DSA) zum Nachweis vaskulärer Komplikationen nach aortoiliakalem/-femoralem Bifurkationsbypass.

From 1970 to 1984 late complications including the prox. anastomosis of aortoiliacal/-femoral bifurcation-prothesis were observed angiographically in 37/647 (6.5%) of patients with art. occl. disease and 4/367 (1.1%) of patients with aneurysmatic disease. Concerning the dist. bilateral anastomotic region the complication-rate was markedly higher. This study was carried out to evaluate accuracy of transvenous DSA in a preselected outpatient group (n = 24) following aortoiliacal/-femoral bifurcation-bypass. In 15 cases DSA showed prothetic complications such as occlusion (n = 4), stenosis (n = 2), anastomotic aneurysms (n = 8) and a.v. fistula (n = 1). The results demonstrate that in outpatients transvenous DSA is a method of low risk to get excellent images of bifurcation-prothesis and prothetic complications considering recommended technical criteria.

[Indications for digital subtraction angiography of the pulmonary vessels]. / Indikationen zur digitalen Subtraktionsangiographie (DSA) der Pulmonalgefässe.

Different indications of pulmonary DSA are discussed based on experiences in 122 cases. The quality and accuracy of imaging is demonstrated by representative examples. Indications of DSA and conventional pulmonary angiography are principally identical. However, our experience in DSA suggests that this minimal invasive procedure may replace conventional angiography in most cases and abolish the strict indication. Supported by further critical tests the high diagnostic quality of DSA imaging in pulmonary embolism and therapeutical control may substitute radionuclide methods (perfusion-ventilation-scintigraphy) to avoid costs of a double examination.

[Intra-arterial digital subtraction angiography (i.a. DSA) in the preoperative diagnosis of abdominal masses]. / Die intraarterielle digitale Subtraktionsangiographie (i.a. DSA) in der präoperativen Diagnostik raumfordernder Prozesse des Abdomens.

The diagnostic value of i.a. DSA, compared with conventional arteriography (n = 48), was proven in patients (n = 116) with abdominal tumours including intrahepatic masses. Arteries supplying the tumour, anomalous vessels and pathological malignant vascular abnormalities were visualised reliably in i.a. DSA despite reduced spatial resolution. An improved definition of hypervascular tumours was possible during the early arterial phase and of hypovascular or avascular masses during the late parenchymal phase of i.a. DSA. The dynamic evaluation of contrast flow is simpler and more reliable using the continuous mode in i.a. DSA than with the static imaging of a conventional film sequence. The advantages of i.a. DSA in preoperative vascular mapping and in detailed diagnosis of abdominal tumours and masses result in replacing conventional arteriography with very few exceptions.

[Transvenous DSA following surgery of the supra-aortic trunks]. / Transvenöse DSA nach operativem Eingriff an den supraaortischen Asten.

This paper presents our experience using transvenous DSA for control of vascular, prosthetic or bypass patency following operative intervention in the supraaortic branches. The results in 33 cases examined under outpatient conditions demonstrate that DSA via transvenous administration of a contrast material with high iodine concentration is useful to produce images of diagnostic quality (32/33 patients). The pre-condition is a good patient's cooperation and a sufficient cardiac output. Using this minimal invasive method the operative results can be evaluated and vascular complications can be excluded.

[Effect of signal-to-noise ratio and window width on image information in transvenous DSA of different vascular regions]. / Einfluss des Signal-Rausch-Verhältnisses und der Fensterbreite auf die Bildinformation bei transvenöser DSA verschiedener Gefässregionen.

The diagnostic quality of DSA images depends on numerous factors related to the apparatus and the technique of examination. An improvement in image can be brought about by correct choice of the mask and injected frames, by subsequent correct manipulation of the images and by the choice of the signal-to-noise ratio and window width. In the present study, the effect of these factors was demonstrated on image quality of venous DSA studies in various vascular regions. Practical advice is given for the examination of particular regions and for various diagnostic problems.

[Percutaneously implanted permanent vena cava filter: follow-up of 117 consecutive patients]. / Perkutan implantierte permanente Vena-cava-Filter: Verlaufsbeobachtungen bei 117 konsekutiven Patienten.

PURPOSE: Retrospective review of indication, insertion technique and problems, complications and effectiveness of 5 different filter designs implanted during a period of 5 years. MATERIALS, PATIENTS AND METHODS: We inserted one Filcard-filter, 4 Antheor DC 3 perm.-filters, 17 Trigon/Cardial-filters, 28 Titan-Greenfield-filters (modified hook) and 65 LGM 30 D/U Vena Tech-filters via a femoral (n = 111) or a jugular (n = 4) approach in 115 of 117 patients. Indication was acute deep thrombosis of the iliac or femoral vein with and without pulmonary embolism (PE) in patients with contraindication to, or unsuccessful, anticoagulation therapy or lysis. Follow-up was possible in 92 patients. RESULTS: In two of 117 patients the filter could not be implanted due to dissection of the left iliac vein. In the other 115 patients we achieved an orthograde position of the filter in 78%, 22% of the filters tilted more than 15 zero and 25% had been opened incompletely. We noticed late filter dislocation in 4 cases, deep vein thrombosis of the access vein in two cases, one haematoma of the insertion site, three asymptomatic perforations of filter struts through the caval wall, 14 filter induced thromboses of the vena cava (15.2%) and 13 recurrent PE (14.1%), fatal in 5 cases (5.4%). CONCLUSION: The implantation of vena caval filters as a prophylaxis of PE is easy and of low risk. Because of the relatively high rate of recurrent PE (14.1%) in our series after implantation, the effectiveness must be judged critically.

[Arterial DSA in malignant hypervascularized bone tumors]. / Arterielle DSA bei malignen hypervaskularisierten Knochentumoren.

In order to evaluate intra-arterial DSA in malignant bone tumors (osteosarcoma n = 2, aggressive osteoblastoma n = 1) three patients were examined angiographically including conventional arteriography and DSA. Compared with conventional angiograms DSA imaging demonstrated a reduced peripheral vascular information due to reduced spatial resolution. Advantages of DSA were an improved visualization of tumor blush and atypical venous return and in addition a reduction of volume rsp. concentration of the contrast material using a iodine concentration of 200 mg/ml for preoperative vascular mapping and of 300 mg/ml for diagnostic tumor imaging.

[Transvenous digital subtraction angiography of the thoracic aorta after surgical correction of isthmic stenosis]. / Transvenöse digitale Subtraktionsangiographie (DSA) der thorakalen Aorta nach operativer Korrektur einer Isthmusstenose.

25 patients (normotensive n = 19, hypertensive n = 6) underwent DSA control following corrective surgery of a coarctation of the thoracic aorta to exclude vascular complications. Simultaneously pressure gradients were determined between upper and lower extremities using the doppler-sonography. DSA was diagnostic in all patients. 2 cases showed a patch-dependent dilatation, in 1 case an anastomotic aneurysm could be demonstrated. In 6 patients with hypoplastic aortic arch and 2 patients with a slight reduction of the diameter in the anastomotic region a pathological pressure-gradient was measured. In these patients the ratio of aortic arch rsp. anastomosis/descending aorta was reduced in diameter (less than 0,66) and area (less than 44). Hypertension could not be related to pressure gradients or vascular disorders.

[Experiences with preoperative and palliative percutaneous transhepatic cholangio-drainage]. / Erfahrungen mit der präoperativen und palliativen perkutanen transhepatischen Cholangiodrainage (PTCD).

In obstructive jaundice PTCD plays an important role as a preoperative or a palliative therapeutic method inspite of the availability of biliary endoprostheses. This study was carried out to assess complications following PTCD, the effect on liver function (serum parameters) and the relationship between duration of preoperative drainage and postoperative complication rate. The results demonstrate that 11-hole pigtail-catheters are useful for intrahepatic location and 32-hole ringcatheters for extrahepatic location due to reduced dislocation rates. The effect of biliary drainage after 7 rsp. 25 days on liver function was significant (p less than 0.05). As a main complication fever episodes could be observed associated with pathologic bile-/bloodcultures in most cases; other complications were similar to those presented in the literature. A prophylactic antibiotic therapy following PTCD seems to be useful, a preoperative biliary drainage is recommended until serum bilirubin levels become constant or at least for 2 weeks.

[The thrombosed popliteal aneurysm: a problem for the interventional radiologist]. / Das thrombosierte Popliteaaneurysma: Ein Problem für den interventionellen Radiologen.

A completely thrombosed aneurysm of the popliteal artery may mimic a simple vascular occlusion both clinically and angiographically. If therapeutical interventions are planned for recanalisation a popliteal aneurysm must be excluded because in such cases vascular surgery is the method of choice. In 11 of 26 patients with an angiographically proven unilateral popliteal occlusion, contrast CT could demonstrate an aneurysm (unilateral n = 7, bilateral n = 4). Real time sonography could confirm unilateral thrombosed aneurysm in 10 of 11 cases; a partially thrombosed contralateral aneurysm was detected in all 4 cases. In contrast to a non-reliable palpable finding both US and or CT are useful in detecting an aneurysmatic degeneration of the popliteal artery. Previous identification of an aneurysm of the abdominal aorta or femoral artery may be helpful in patient selection.

[Contrast-enhanced CT of the mediastinum in lymph node diagnosis]. / Kontrastmittel-CT des Mediastinums zur Lymphknotendiagnostik.

In mediastinal lymphoadenopathy diagnostic problems arise if lymphomas are of the same density as cardial or vascular structures. For this reason, CT based on contrast enhancement must definitely ensure a significantly greater enhancement of vascular structures than of non-vascular ones during the entire scan period. We studied 4 groups of 20 patients each employing standardised CT examinations employing 100 ml. contrast medium in different concentrations (200 and 300 mg. iodine/ml., respectively) and an injection flow rate of 0.7 and 2.0 ml/s. The results show that higher iodine concentrations produce a significantly greater enhancement in the aorta than a lower iodine concentration independent of the flow rate. Although a lower flow rate slightly delayed the enhancement increase, this was nevertheless higher than 60 HU within a period of 4 minutes. Hence, we recommend to perform contrast enhanced CT of the mediastinum using lower flow rates (0.5-1.0 ml/s.) and a higher contrast medium concentration (300 mg. iodine/ml.).

[The evaluation of 2D- and 3D-"time of flight" magnetic resonance angiography (MRA) in the diagnosis of renal artery stenoses]. / Bewertung der 2D- und 3D-"Time-of-flight"-Magnetresonanz-Angiographie (MRA) in der Diagnostik von Nierenarterienstenosen.

This study was carried out to evaluate time-of-flight RA in renal artery stenosis (RAS) in selected hypertensive patients (n = 41). In i.a. DSA studies, 10 unilateral, 8 bilateral RAS, and 4 unilateral RA occlusions were proven. MRA was done in coronal and axial 2D technique (FLASH), and in 3D technique (FISP) using GE-pulse sequences. DSA results were correlated with both 2D-individual slices, 2D- and 3D-MIP angiograms. Highest sensitivity and specificity was found for the axial 2D individual slice analysis (88%, 85% resp.), followed by the 3D-MIP MRA (78%, 80% resp.), and axial 2D-MIP MRA (73%, 79% resp.). MRA of renal arteries used in this study shows to be not adequate to DSA results due to many drawbacks. All MRA techniques, in particular the 3D-technique, tend to overestimate RAS occasionally pretending occlusions.