Strengths and limitations of coronary angiography with turbo high-pitch third-generation dual-source CT.

AIM: To define practical limitations of diagnostic image quality for recently introduced turbo high-pitch scan mode (THP) in third-generation dual-source computed tomography (CT). MATERIALS AND METHODS: Two hundred and twenty-nine consecutive patients undergoing CT coronary angiography were included in this retrospective single-centre analysis. A contrast-enhanced volume dataset was acquired in THP. Image quality of coronary segments was classified as diagnostic or non-diagnostic by three blinded readers. Segments were stated as non-diagnostic if at least one of three readers could neither exclude nor confirm significant stenoses. Multivariable logistic regression was used to assess relationships between number of non-diagnostic segments and common influencing factors. RESULTS: Median effective radiation dose was 0.6 (interquartile range [IQR], 0.4-0.8) mSv overall and 0.3 (IQR, 0.3-0.4) mSv in the 70 kV subgroup of this middle aged, predominantly pre-obese cohort (age: 61 [IQR, 52-67] years; body mass index [BMI]: 26 [IQR, 23-29] kg/m2) with a low-moderate median Agatston score (AS) 0 (IQR, 0-70). Diagnostic image quality was found in 98.1% of 3,678 coronary segments. AS was independently associated with diagnostic image quality (B=0.34; p=0.02), whereas heart rate, BMI, and presence of arrhythmia were not. The portion of diagnostic coronary segments decreased slightly in obese patients with heart rates >65 beats/min and dropped significantly in patients with an AS >600 (p=0.003). CONCLUSION: THP enables CT coronary angiography with minimal radiation exposure and is most appropriate in non-obese patients with stable sinus rhythm ≤65 beats/min and a calcium score ≤600.

Biomechanics applied to incisional hernia repair - Considering the critical and the gained resistance towards impacts related to pressure.

BACKGROUND: Incisional hernia repair is burdened with recurrence, pain and disability. The repair is usually carried out with a textile mesh fixed between the layers of the abdominal wall. METHODS: We developed a bench test with low cyclic loading. The test uses dynamic intermittent strain resembling coughs. We applied preoperative computed tomography of the abdomen at rest and during Valsalva's maneuver to the individual patient to analyze tissue elasticity. FINDINGS: The mesh, its placements and overlap, the type and distribution of fixation elements, the elasticity of the tissue of the individual and the closure of the abdominal defect-all aspects influence the reconstruction necessary. Each influence can be attributed to a relative numerical quantity which can be summed up into a characterizing value. The elasticity of the tissues within the abdominal wall of the individual patient can be assessed with low-dose computed tomography of the abdomen with Valsalva's maneuver. We established a procedure to integrate the results into a surgical concept. We demonstrate potential computer algorithms using non-rigid b-spline registration and artificial intelligence to further improve the evaluation process. INTERPRETATION: The bench test yields relative values for the characterization of hernia, mesh and fixation. It can be applied to patient care using established procedures. The clinical application in the first ninety-six patients shows no recurrences and reduced pain levels after one year. The concept has been spread to other surgical groups with the same results in another fifty patients. Future efforts will make the abdominal wall reconstruction more predictable.

Endovascular stenting in patients with Iliac compression syndrome. Experience in three cases.

The authors report their experience in the percutaneous treatment of the iliac compression syndrome in three women (20-53 years old) with acute iliofemoral deep venous thrombosis; in one case, there was an additional thrombus in the inferior caval vein. They were treated by percutaneous implantation of Palmaz stents in the left common iliac vein 1 day after surgical thrombectomy and construction of an arterial venous fistula. All patients showed marked improvement, as determined from venograms obtained immediately after stent implantation. The arteriovenous fistulae were closed 3 months later. At 6 months follow-up, the median clinical and color-coded duplex ultrasound indicates that all stents are patent and all patients are free of symptoms.

Endovascular stent-graft placement versus conventional open surgery in infrarenal aortic aneurysm: a prospective study on acute phase response and clinical outcome.

BACKGROUND: For the treatment of aortic aneurysm, stent-graft implantation is an alternative method to open surgery. There is no study comparing both methods with regard to endotoxaemia, the acute phase cascade, and clinical outcome. METHODS: In this prospective study, we enrolled 40 patients (34 males, 6 females; mean age 72.1+/-7.5 [58-92] years) with infrarenal abdominal aortic aneurysm who underwent aortic surgery. Comparable groups of patients were treated with open (n=20) or endovascular (n=20) stent-graft implantation. To characterize the inflammatory response, plasma levels of endotoxin, endotoxin-neutralizing capacity (ENC), interleukin-6 (IL-6), C-reactive protein (CRP), and white blood cell count were determined. In all patients, measurements were performed on admission, skin suture, 4 h and from the first to fifth postoperative day. As parameters for the clinical outcome, we assessed daily temperature, lung function, pain, duration of postoperative hospital stay, and morbidity. Wilcoxon rank test was used for statistical analysis. RESULTS: In both groups, a significant increase of endotoxin plasma levels and a decrease of ENC was found already after skin incision. IL-6 levels peaked 4 h postoperatively in both groups, whereas CRP rose at the first postoperative day, reaching a maximum at day 2. Conventionally operated patients had significantly higher plasma levels of endotoxin, IL-6, and CRP and lower ENC during and after surgery than patients with stent-graft implantation. Moreover, patients with endovascular stent grafting had significant less postoperative pain, less restriction of total vital capacity, a shorter hospital stay, and a lower morbidity. CONCLUSIONS: Endovascular stent grafting of infrarenal aortic aneurysm seems to be superior not only in terms of the inflammatory response but also in overall clinical outcome.

Palliative and adjuvant regional chemotherapy in pancreatic cancer.

To improve the dismal prognosis of patients (pts) with pancreatic cancer we treated 32 patients with non-resectable (UICC III, 17 pts; UICC IV, 15 pts--group 1) and 20 patients with resected (UICC I, 1 pt; UICC II, 3 pts; UICC III, 16 pts--group 2) pancreatic cancer with palliative (group I) and adjuvant post-operative (group II) coeliac axis intra-arterial cyclic infusions (CAI). CAI consisted of mitoxantrone 10 mg/m2 on day 1, folinic acid 170 mg/m2 and 5-FU 600 mg/m2 during days 2-4, and cis-platinum 60 mg/m2 on day 5 for up to 11 (group I) or six (group II) cycles. In a total of 211 cycles toxicities at the level of WHO III occurred in 0-6% and of WHO IV in 0%. The median survival times, compared with institutional historical controls (treated vs controls), were 12 vs 4.8 months in UICC III (P < 0.006) and 4 vs 2.9 months in UICC IV (P < 0.05) group I pts, and 21 vs 9.3 months in group II (P < 0.0003). Hepatic disease progression appeared to be suppressed with CAI, which also appears to be effective for palliative and adjuvant treatment in non-resectable and resected pancreatic cancer.

Intraductal papillary mucinous tumor of the pancreas.

BACKGROUND: Since 1996 the classification of pancreatic tumors was replaced by the new World Health Organization nomenclature. Formerly mucinous cystadenomas are now distinguished between intraductal papillary mucinous tumors of the pancreas (IPMT) and mucinous cystadenomas. METHODS: We reevaluated the pathological specimen and surgical therapy of 23 consecutive patients and followed up these patients up for 4 years in median. Between 1987 and 1997 we treated 8 patients with IPMT and 15 patients with mucinous cystadenomas. RESULTS: Eighty-five per cent of all patients were symptomatic. Ultrasonography and computed tomography were the most sensitive diagnostic techniques. In 25%, the entire pancreas was involved with IPMT; that was not the case in any of the patients with mucinous cystadenoma. All patients were resected with no perioperative mortality. After dismissal from the hospital, all resected patients are still alive after a median follow-up of 4 years. In no patient with IPMT, but in 1 patient with mucinous cystadenoma, the tumor recurred. CONCLUSION: Surgical resection is the treatment of choice in all cystic tumors, and the late outcome of IPMT is as good as for mucinous cystadenoma.

MRI of breast cancer: influence of chemotherapy on sensitivity.

MR mammography (MRM) seems to be a sensitive method for detection of breast cancer. The effect of cytotoxic agents on the dynamics of contrast medium uptake in primary breast carcinoma or recurrent disease is not known. This study addresses this question and evaluates MRM as a method of monitoring therapeutic success. A total of 13 patients (age range 34-62 years) with histologically confirmed breast cancer were investigated. The patients received neoadjuvant intravenous (iv) chemotherapy. MRM and interpretation of the dynamic measurements were performed in a standardized manner after positioning the patient in a double breast coil. A gradient echo sequence (Flash 3D, TE 5 ms, TR 12 ms, flip angle 25 degrees) was acquired before and 1, 2, 3 and 8 min after intravenous injection of Gd-DTPA 0.15 mmol kg-1 body weight. A T2 weighted SE sequence (TE 103 ms, TR 6900 ms, 4 mm, field of view 350 mm) was also obtained. MRM was performed prior to histological evaluation and after chemotherapy. All cases of malignancy were correctly diagnosed with MRM. Based on MR findings, eight patients were classified as "responders" and the remaining as "non-responders". In the "responders" a flattening of the Gd-DTPA uptake curve after the first cycle of chemotherapy of complete absence of Gd-DTPA uptake after the fourth cycle was observed. The change in Gd-DTPA uptake behaviour led to an underestimation of the extent of tumour in two patients and false negative findings in four patients. MRM provides information regarding response to therapy following the first cycle. MRM does not provide information regarding invasive tumour tissue in "responders".

Mechanical thrombectomy of embolic occlusion in both the profunda femoris and superficial femoral arteries in critical limb ischaemia.

We report our preliminary experience using the Amplatz device for percutaneous thromboembolectomy in acute occlusion in both the profunda femoris artery (PFA) and superficial femoral artery (SFA) in four patients (mean age 78.5 years). All patients suffered from acute lower limb ischaemia, Fontaine Grade 3, due to cardiac embolization. Estimated occlusion times range from 3 h to 3 days. All four patients were treated successfully. Device activation time for both the PFA and the SFA was 85 s +/- 15 s. Total procedure time was 25 min +/- 10 min. There was no need for adjunctive procedures or intensive care monitoring. We conclude that the Amplatz device is a very effective and safe procedure for the quick restoration of vascular patency in cases of simultaneous embolically occluded PFA and SFA.

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.

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.

[Intra-arterial angio-CT as a perfusion control before intra-arterial chemotherapy in bronchial, breast and liver tumors]. / Intraarterielles Angio-CT als Perfusionskontrolle vor intraarterieller Chemotherapie bei Bronchial-, Mamma- und Lebertumoren.

Intra-arterial angio-CT is used increasingly in the diagnosis of liver metastases since the sensitivity of this method is greater than that of IV-contrast CTs. We carried out this procedure in eight patients with inoperable carcinomas of the bronchus, eight patients with carcinoma of the breast, one patient with an hepatocellular carcinoma and one patient with carcinoma metastases, before starting intra-arterial chemotherapy or tumour embolisation. The procedure permitted optimal placing of the catheter to ensure complete perfusion of the tumour. Perfusion of normal tissue can be reduced to a minimum. Failure of contrast filling on the angio-CT indicates the presence of a second vessel supplying the tumour.

[Non-occlusive mesenteric ischemia]. / Non-okklusive Darmischämie: Radiologische Diagnostik und Therapie.

The so-called non-occlusive disease (NOD) or non-occlusive mesenteric ischemia (NOMI) is a severe and life-threatening pathology. Even under optimal circumstances and standardised diagnostic and therapeutic procedures maximum survival rates do not exceed 50 %. The NOD is a pathology of the elder patient and its incidence rises with other comorbidities such as reduced cardiac output, diabetes and renal insufficiency. Induction of the disease with a severe vasoconstriction of the splanchnic vessels may be a simple cardiac decompensation, a frequent trigger however is a previous heart surgery with consecutive cardiac shock. Early diagnosis is difficult to conduct because of unspecific symptoms. Beside abdominal pain in awake patients, ileus or subileus is remaining the single acute symptom which could be also a consequence of a postoperative paralysis. Laboratory parameters such as leucocytosis and elevated lactat levels are often positive, but unspecific and the latter may be a delayed sign of progressive disease. The only sufficient method for diagnosis implicating a possible treatment option seems to be an immediate angiographic examination. Because of the disappointing results of a solitary surgical approach transarterial medication via catheter is indicated. Depending of the course of the disease only a combination of local mesenteric infusion of vasodilatory drugs and surgical resection of already necrotic bowel promises a successful therapeutic approach and better survival rates.

[Presentation of a new self-expanding vascular spiral stent]. / Vorstellung eines neuen selbstexpandierenden vaskulären Spiralstents.

The technical details as well as first clinical results of a newly developed Nitinol stent are presented. The spiral-shaped Nitinol stent was implanted in two patients with complicated peripheral arterial obstruction after bypass surgery. Stent implantation was very exact and technically simple using a special implantation catheter. While one patient is free of symptoms three months after stent implantation, an early obstruction was observed in the other patient one day after the interventional procedure. The specific spiral design allows a simple percutaneous extraction of the stent. A cross-over use of the stent seems principally possible, but limited due to the length of the implantation catheter of 70 cm. Prospective clinical studies are, however, warranted.

[Computed tomographic findings in bronchial adenoma]. / Computertomographische Befunde beim Bronchialadenom.

The diagnostic value of CT was studied in 36 patients with histologically proved bronchial adenomas. Peripheral masses were found in 16% of the patients. Mediastinal metastases were detected at operation in 8 (22%) of these patients. Two patients showed distant metastases. We were not able to find reliable CT criteria for bronchial adenomas.

[Size and density determination by thin-layer CT in relation to structural diameter and the contrast of the surrounding tissue]. / Grössen- und Dichtebestimmung mit der Dünnschicht-CT in Abhängigkeit von Strukturdurchmesser und Umgebungskontrast.

The reliability of CT size and density measurements has been examined by using phantom measurements with constant examination and reconstruction parameters (Somatom DRH/Siemens). Ten plexiglass rods with diameters from 2 to 15 mm. were measured singly in (1) air, (2) isodense (146 Hu) and (3) hyperdense medium (985 Hu) using 2 mm. sections. In the isodense medium there was only small variation in density measurements (124 to 131 Hu). Measurements of size showed a maximum error up to -35%. Density measurements in the hyperdense medium produced raised values (197 +/- 17 Hu at 15 mm.). There was an even greater increase for rods smaller than 5 mm. Measurement of size was correct, as it was in air (maximum deviation 8%). Density measurements in air for diameters less than 6 mm. were significantly reduced.

[Quantitative and morphologic information value of the SPECT perfusion study of thoracic space-occupying lesions]. / Quantitative und morphologische Aussagekraft der Spect-Perfusionsuntersuchung bei thorakalen Raumforderungen.

The results of planar perfusion scintigraphy, SPECT and CT were evaluated quantitatively and compared with each other in 47 patients with thoracic tumours. SPECT was superior to conventional scintigraphy in respect of morphological information. Quantitative evaluation of the function data derived from SPECT permits a more detailed anatomical recognition of perfusion inhomogeneity due to the tumour and can distinguish between central and peripheral tumour growth. Comparison between CT and SPECT showed good morphological agreement between the two.

[DIL vena cava filter. Initial experiences in 15 patients]. / DIL Vena-Cava-Filter. Erste Erfahrungen bei 15 Patienten.

DIL filters were permanently inserted through the cubital vein, using a 7-F catheter, in 15 patients and were followed up for six months in 12 patients. One filter could not be opened and 4 others were only partly open. Clinically there were no recurrences of pulmonary emboli. There were no complications from the correctly placed filters. Amongst the 4 incompletely expanded filters, two caused perforation of the cava, in one the cava thrombosed and in another the filter migrated to the bifurcation of the pulmonary artery. It follows that unexpanded filters should not be placed in the cava. Measurements in 10 patients showed the cava reduced to less than 10 mm lumen. In two cases the reduction of lumen was only slight, measuring more than 15 mm. The effect of the reduction in the lumen remains to be compared with that achieved by other filters.

[A new method in the determination of individual delay time in bolus application in spiral CT]. / Neues Verfahren zur Bestimmung der individuellen Verzögerungszeit für die Bolusapplikation im Spiral-CT.

Helical-CT examinations, particularly CT angiography, require precise timing between the examination procedure and the individual dynamics of contrast medium distribution in the arteriovenous system of the patient. The necessary delay between contrast medium injection and onset of has usually been either estimated or determined by means of an additional helical CT examination. The present paper introduces a new technique which allows bolus analysis without an additional scan. Prior to a CT angiography with 10 patients, two techniques for bolus analysis (BA) were compared. Prior to diagnostic contrast medium enhanced examination, a native (BA I) and a dynamic (BA II) examination were performed. Ten seconds prior to the start of each examination, a 10 ml test bolus was applied with an injection flow rate of 3 ml/s. Both examinations lasted for 30 s. During BA I, increase in attenuation in the aorta was compared at different sites, during BA II consistently at the same site. Comparison of the individual peak times yielded a coefficient of correlation of r = 0.926. The median value for BA I was 18.4 +/- 5.4 s and 19.2 +/- 4.5 s for BA II. The difference between measurement of peak time was 1.2 +/- 1.16 s. This modified technique for bolus analysis during the primary native scan of the upper abdominal organs permits calculation of the required individual delay time between contrast medium application and scan start: no additional examination is required and the method can be performed with any helical CT unit.

[Interventional treatment of hemobilia]. / Interventionelle Behandlung der Hämobilie.

PURPOSE: Aim of the study was to assess the use of embolisation in cases of iatrogenic haemobilia. METHOD: In 18 patients with severe haemobilia after percutaneous biliary system drainage or stent implantation, an embolisation with minicoils (17 x) or gelfoam particles, was performed. To achieve a sufficient vascular obstruction, Histoacryl (4 x) or Ethibloc (1 x) were additionally used in five cases. A transarterial approach was used in 17 cases. In one patient, an approach through the biliary system was possible. RESULTS: In all cases, the bleeding source was identified (5 false aneurysms, three biliary leaks, 9 irregularities at the junction of the artery and drainage catheter, 1 multiple collaterals at the proximal end of the stent). In 17 out of 18 cases, haemorrhage ceased definitely. In one case of a patient with pancreas carcinoma and obstruction of the portal vein as well as a simultaneous high grade stenosis of the hepatic artery propria, it was only possible to embolise small collaterals to avoid liver necrosis. This resulted in an incomplete bleeding of control. An infected haematoma was the only complication. It was treated by drainage over 10 days. During an observation period ranging approximately 7.6 months, 10 of the patients died due to their basic illness. CONCLUSION: Embolisation is an effective procedure in the treatment of haemobilia, with a low complication rate.

[The nitinol stent as a palliative measure in inoperable carcinoma of the esophagus and cardia. Possibilities and limitations of the procedure]. / Der Nitinolstent als Palliativmassnahme bei inoperablem Osophagus- und Kardiakarzinom. Möglichkeiten und Grenzen des Verfahrens.

Nitinol stents were used in ten patients as palliative treatment for carcinoma of the esophagus and the cardia. Following insertion of the stent the severity of dysphagia decreased on average from 3.2 to 1.5 (on a scale from 0-4). Difficulties with stent opening and passage through the gut were found particularly in the region of metal sutures at esophago-jejunal anastomoses. One stent, which had been obstructed by mucosal folds, had to be removed and replaced. One stent which had been incorrectly placed was extended by introducing a second stent by a coaxial technique. During the period of observation, six patients died after an average of 4.6 months. The palliative effect of the stent lasted on average for eleven weeks. In two patients the tumour grew beyond the stent and in three there was tumour growth into the stent.