[Multidetector computed tomography (MDCT) of the kidneys]. / Multidetektorcomputertomographie (MDCT) der Nieren.

Multidetector computed tomography (MDCT) possesses distinct advantages for examination of the kidneys. It carries the potential of becoming the gold standard of diagnostic work-up and surgical planning for most renal diseases and replacing conventional methods such as i.v. urography and angiography. The most outstanding improvements, in comparison to single slice spiral CT, are the speedier image acquisition and enhanced z-axis resolution, which aids particularly in visualization of the urinary tract as it aligns along the axis of the body. Respiratory artifacts are few or nonexistent even in patients who cannot hold their breath. This overview presents a strategy for prudent management of MDCT examinations and describes examination of the most important and frequent renal diseases using MDCT.

[Contrast-enhanced sonography of the liver]. / Kontrastverstärkte Sonographie der Leber.

The detection rate of liver lesions using ultrasonography is 53-77%, rendering this method inferior to CT and MRI. Despite well-known limitations, development of stable second-generation contrast agents in conjunction with new techniques of contrast display has led to increased diagnostic accuracy. Characterization of focal liver lesions with ultrasound contrast agents follows known features of iodine- and gadolinium-containing contrast agents, but compared to CT and MRI sensitive visualization of intratumoral vessels takes place in real time. In addition to very high diagnostic accuracy in differentiating benign from malignant lesions, detectability of tumors of nonhepatocellular origin is increased significantly and direct assessment of treatment success with minimally invasive tumor ablative interventions in the liver is possible. The active principle of ultrasound contrast agents, examination technique as well as distinguishing features and appearance of various, frequently observed focal liver lesions are illustrated by cases from our department.

Efficacy of superficial and deep regional hyperthermia combined with systemic chemotherapy and radiotherapy in metastatic melanoma.

BACKGROUND AND OBJECTIVE: Response rates of cutaneous-subcutaneous or lymph node metastases of melanoma to systemic chemotherapy are rather low. We report our clinical experience with superficial and deep regional hyperthermia in combination with radiotherapy and/or chemotherapy with carboplatin. PATIENTS/METHODS: We treated 15 patients with metastatic melanoma (6 men, 9 women; age 39-84 years, mean age 60 years) by using superficial or deep regional hyperthermia produced by electromagnetic energy. Superficial hyperthermia was delivered to skin or lymph node metastases in combination with radiochemotherapy in 12 patients, while deep regional hyperthermia was administered with an annular array applicator to lymph node metastases either in combination with radiochemotherapy (1 patient) or with carboplatin alone (2 patients). The clinical response was assessed by clinical evaluation and/or computer tomography and/or ultrasonography at monthly intervals. RESULTS: Both superficial and deep regional hyperthermia was well tolerated. We observed 5 complete local remissions (34%), 6 partial local remissions (40%) and 2 patients with stable disease (13%). The best results were obtained in cutaneous or retroperitoneal metastases. CONCLUSIONS: Local response can be achieved in inoperable metastatic melanoma using superficial or deep regional hyperthermia in combination with radiochemotherapy or chemotherapy.

Helical CT of the urinary organs.

Despite of the diagnostic potential of conventional CT (CCT), limitations being inherent in this technology reduce its diagnostic confidence and limit clinical CT applications as 3D imaging. Helical CT (HCT) has far overcome the limitations of CCT and has become the standard CT technology. After a short overview on the technique of HCT and its advantages over CCT, the impact of HCT on the detection of disorders of the urinary organs is discussed. Due to the high quality of 3D reconstructions, vessels are visualized free of artefacts resulting in a dramatic improvement and acceptance of CT angiography, which has become a clinically important examination in the evaluation of obstructive renal artery disease. Fast HCT provides a precise assessment of the three phases of the nephrogram and it is a prerequisite for an improved depiction of abnormal vascular perfusion and impaired tubule transit of contrast material. Helical CT enables an improved characterization of cystic mass lesions reducing the diagnosis of indeterminate masses and thus facilitating a better therapeutic management. The diagnosis of renal cell carcinomas (RCC) has improved due to an increased sensitivity in detecting small RCCs, and an increased specificity in the diagnosis of neoplastic lesions. Improved staging of RCCs is the result of accurate assessment of venous tumour extension. When planning nephron-sparing surgery 3D display of the renal tumour helps to determine the resectability of the mass depicting its relation to major renal vessels and the renal collecting system. In the evaluation of renal trauma HCT provides shorter scanning time and thus fewer artefacts in the examination of traumatized patients who cannot cooperate adequately. Three-dimensional postprocessing modalities allow the assessment of the renal vascular pedicel by CT angiography and improve the demonstration of complex lacerations of the renal parenchyma. In the evaluation of the upper urinary tract unenhanced HCT has become the imaging method of choice in the diagnosis and differential diagnosis of acute flank pain since it is highly sensitive and specific in detecting calculus disease. Unenhanced HCT may furthermore demonstrate causes of flank pain unrelated to urolithiasis. Gapless volume scanning and improved resolution in the z-axis during the excretory phase enables improved visualization of the renal collecting systems and ureters, resulting in a better demonstration of intraluminal and extraluminal pathology.

Quantitative and qualitative analysis of in vivo Doppler signal enhancement of FS-069.

RATIONALE AND OBJECTIVES: In vivo lifetime of ultrasound (US) contrast agents is still limited and thus a cause for ongoing investigations of new substances. The purpose of this study was to determine the time intensity changes of the Doppler signals obtained within the femoral vein after two different doses of a new microsphere-based ultrasound contrast agent. METHODS: Twenty-four healthy male volunteers (mean age, 29; average weight, 76 kg) were included in this study. All underwent a triplex Doppler US examination after an intravenous bolus injection of 0.3 mL and 1.0 mL Optison. To examine the signal enhancement characteristics of this contrast agent the audio signal of the pulsed-wave spectral Doppler US was measured quantitatively using an audio analyzer, whereas velocity-encoded color Doppler examinations were scored qualitatively (score 0-3). RESULTS: The mean maximal enhancement of the audio signal at a dose of 1.0 mL FS-069 was significantly higher than with a bolus of 0.3 mL FS-069 (29 +/- 2 dB vs. 26 dB +/- 2 dB, P < 0.001). The time-intensity curves after each bolus injection yielded an early peak (one minute after the injection) followed by constantly decreasing signal intensities. The scoring of the velocity-encoded color Doppler US revealed an optimal enhancement (score 2) for 3 minutes and 20 seconds (0.3 mL Optison) and for 6 minutes (1.0 mL Optison), respectively. CONCLUSIONS: This study showed the capability of triplex Doppler ultrasound signal enhancement after Optison. 1.0 mL Optison proved to be the more appropriate dose for an optimal signal enhancement than 0.3 mL Optison.

Handicap of walking by a huge paratesticular liposarcoma.

We describe the case of a 71-year-old male with a huge left-sided paratesticular tumour, whose walking was increasingly handicapped by this vast mass. Two palliative excisions of tumour tissue were performed. Histology revealed a poorly differentiated paratesticular liposarcoma. The patient achieved satisfying mobility for several months before he died of cachexia.

Focal nodular hyperplasia and hepatocellular adenoma of the liver: differentiation with multiphasic helical CT.

OBJECTIVE: Differences of attenuation and enhancement patterns in focal nodular hyperplasia and hepatocellular adenoma were evaluated and quantified using triphasic single-slice helical CT. MATERIALS AND METHODS: Forty-five histologically proven focal nodular hyperplasias in 27 patients and 18 hepatocellular adenomas in six patients were examined with helical CT. Quantitative evaluation included the following: attenuation of lesions, scar, and liver parenchyma during unenhanced, arterial (20 sec after injection), and portal venous phases (70 sec after injection); relative enhancement of lesions and liver (the ratio between attenuation in arterial phase and portal venous phase, respectively, and attenuation in unenhanced phase); and the prevalence of scar and its central vessel in focal nodular hyperplasia. RESULTS: The study showed no significant difference between mean attenuation values of focal nodular hyperplasia (mean +/- SD, 51.2 +/- 5.9 H) and hepatocellular adenoma (mean +/- SD, 56.3 +/- 7.8 H) in the unenhanced phase. In the arterial phase attenuation values were significantly higher in focal nodular hyperplasia (mean +/- SD, 117.9 +/- 15.1 H) than in hepatocellular adenoma (mean +/- SD, 80.1 +/- 10.5 H). In the portal venous phase no significant differences in attenuation values were detected between focal nodular hyperplasia (mean +/- SD, 112.1 +/- 20.4 H) and hepatocellular adenoma (mean +/- SD, 110.2 +/- 12.9 H). For enhancement parameter thresholds separating focal nodular hyperplasia from hepatocellular adenoma, the following were found: the relative enhancement was higher in 100% of the focal nodular hyperplasias and lower than or equal to 1.6 (accuracy, 96%) in 87% of the hepatocellular adenomas. CONCLUSION: Triphasic helical CT combined with quantitative evaluation of liver lesions offers the possibility of detecting differences in liver lesions that are visually similar on CT. The attenuation and relative enhancement in the arterial phase show significant differences that make accurate differentiation between focal nodular hyperplasia and hepatocellular adenoma possible.

Echo-enhanced color Doppler sonography in children and adolescents.

Fifty-one patients, with a range of underlying pathologic conditions, were studied prospectively to assess the diagnostic value of echo-enhanced color Doppler sonography in the pediatric and adolescent population Their diagnoses included various tumors, vascular disorders, cerebral bleeding, pathologic conditions of small parts, and focal lesions of parenchymal organs. All patients underwent color Doppler sonography before proceeding to echo-enhanced color Doppler sonography. Diagnoses were confirmed by additional imaging (computed tomography, magnetic resonance imaging, angiography, and scintigraphy) performed as appropriate, with or without histologic study. An additional 20 children did not proceed to echoenhanced color Doppler sonography as color Doppler sonography alone was found to be sufficiently diagnostic. Levovist (SHU 508A), a contrast agent based on galactose-encapsulated air microbubbles, is approved for pediatric applications in Austria and was used as the echo-enhancing agent. Echo-enhanced color Doppler sonography was performed a total of 63 times in 51 patients (mean age, 9.8 years). Compared to color Doppler sonography, echo-enhanced color Doppler sonography either detected or enhanced visualization of pathologic conditions in 55 investigations (87.3%), yielding an overall accuracy of 95.2% (sensitivity, 95%), versus 65.7% with color Doppler sonography. One spinal arteriovenous malformation, one cerebral cavernoma, and one liver lesion were missed. The contrast material was easy to administer; no adverse reactions were observed. We conclude that echoenhanced color Doppler sonography is beneficial in pediatric sonography. It enhances visualization of vessels and perfusion, thus offering a nonionizing imaging tool for detection and follow-up evaluation of pathologic conditions with disturbed vasculature in specific cases. In infants and in persons with superficial lesions it did not offer significant advantages over color Doppler sonography.

[Current status of diagnostic imaging of focal nodular hyperplasia of the liver]. / Aktueller Stand der bildgebenden Diagnostik der fokalen nodulären Hyperplasie der Leber.

Ranging behind hemangiomas, focal nodular hyperplasias (FNH) are the second most common benign solid liver lesions. Women between the age of 20 and 50 years are predominantly affected. In rare cases FNH may occur in children. Etiologically, an arteriovenous vascular malformation of the liver is discussed, which causes pseudotumorous growth of the surrounding liver parenchyma. Morphological features such as the presence of a radial vascular architecture and feeding arteries within a central scar are characteristic for the presence of FNH. Imaging techniques which enable the depiction of the arterial blood supply with a characteristic centrifugal filling pattern, the contrast enhancement in the early arterial phase, the absence of calcifications and of a tumour capsule and the typical enhancement of the central scar, are of particular importance. Knowledge of these features is important in order to differentiate FNH from other hypervascular focal liver lesions with tendency of scar formation, such as hepatic adenomas, giant hemangiomas, hepatocellular and fibrolamellar carcinomas, and metastases. Diagnosis and differential diagnosis of FNH will be enabled by a combined modality approach consisting of (Doppler) sonography and triphasic CT. To confirm the diagnosis of FNH, dynamic MRI is advisable. Because of the invasiveness of angiography as well as the limited sensitivity and spatial resolution of the various scintigraphic methods, these modalities no longer play a role in the diagnostic work-up of FNH. Lesions lacking typical features diagnostic for FNH remain subjects for biopsy and histological examination.

Bronchogenic cyst appearing as a hepatic mass.

Because bronchogenic cysts may be found in or near any organ derived from the embryonic foregut, they sometimes pose considerable diagnostic difficulties. We describe the plain chest X-ray, computed tomographic, and angiographic findings in a patient with elevated CA 19-9 and upper quadrant abdominal pain due to a cystic tumor appearing as a hepatic mass. Surgery and histology showed a bronchogenic cyst located in the lower lobe of the right lung.

Contrast-enhanced spiral CT of the head and neck: comparison of contrast material injection rates.

BACKGROUND AND PURPOSE: Contrast-enhanced spiral CT studies of the head and neck are performed frequently using contrast material volumes of approximately 30 g iodine and a scan delay of 30-45 seconds. Because little is known about the effects of contrast material injection rates on tissue enhancement, this was prospectively investigated in our study. METHODS: Ninety-seven patients underwent spiral CT of the head and neck. Each patient was assigned randomly to one of four groups who received 100 mL of nonionic contrast material (300 mg I/mL) at different monophasic injection flow rates with 1.5, 2, 3, and 4 mL/s. Scanning started after a constant delay of 35 seconds. The attenuation of the carotid artery, jugular vein, and sternocleidomastoid muscle was measured over time and the attenuation of the submandibular and thyroid gland was evaluated. Vascular attenuation of at least 150 HU was considered to be sufficient. RESULTS: The mean scan time was 33+/-5 seconds. The study, using an injection rate of 2 mL/s, showed the longest time of sufficient overall (arterial and venous) vessel attenuation (27+/-4 seconds, P< or =.008). The injection flow rate did not influence significantly muscular attenuation (mean enhancement during scan time: 9+/-7 HU). The 1.5 mL/s protocol showed the lowest attenuation values of the submandibular gland (81+/-12 HU) and the highest attenuation values of the thyroid gland (164+/-22 HU), but the attenuation of the thyroid gland was not statistically different from that revealed by the 2 mL/s protocol. CONCLUSION: Using 100 mL of intravenous contrast material with 300 mg I/mL for spiral CT studies of the entire head and neck, the optimal injection flow is 2 mL/s, whereas lower flow rates resulted in insufficient venous enhancement.

Drop metastases in a patient with a chondroid chordoma of the clivus.

Metastasising chordomas are extremely rare and only four cases with drop metastases have been reported. We report a patient with an intracranial chondroid chordoma, typically involving the clivus, treated by repeated resection, percutaneous transluminal embolisation and radiosurgery. During follow-up with MRI asymptomatic intradural drop metastases were observed throughout the spine, with transgression of the intervertebral foramen, forming a "dumbbell".

Renal masses--evaluation by amplitude coded colour Doppler sonography and multiphasic contrast-enhanced CT.

OBJECTIVE: To assess the efficacy of amplitude coded colour Doppler US (aCDS) in the evaluation of renal masses as shown by multiphasic contrast-enhanced CT. MATERIAL AND METHODS: Eighty patients (155 kidneys) with suspicion of renal masses underwent aCDS and spiral CT. The findings were classified into normal kidneys, kidneys with tumours, kidneys with cysts, and those with "other findings" (i.e. bleeding, calcifications, inflammation, parenchymal hypertrophy). The aCDS findings were compared to CT results and to histological findings or clinical, laboratory and follow-up data. RESULTS: Eighteen renal cell carcinomas and 8 other tumours were found; 78 kidneys had cysts, 12 polycystic kidneys and 10 fibrotic kidneys were detected, 20 kidneys showed other findings. Diagnostic aCDS data were obtained in 129 kidneys (83.2%) showing pathology with an accuracy of 94%. CT adequately showed pathology in all patients with some diagnostic uncertainty in the evaluation of complicated cysts. CONCLUSION: Though contrast-enhanced multiphasic spiral CT is the method of choice for evaluating renal masses, US including aCDS can provide valuable information, particularly in differentiating vascularized from non-vascularized lesions and in the evaluation of complicated renal cysts.

Echo-enhanced Doppler sonography of focal nodular hyperplasia of the liver.

Lesions of focal nodular hyperplasia are hypervascular, benign focal liver lesions whose differentiation from other focal liver lesions is of significant clinical relevance. The purpose of this study was to investigate the echo-enhancing agent SHU 508A (Levovist) in the evaluation of focal nodular hyperplasia with Doppler sonography. We examined 49 patients with 71 lesions of focal nodular hyperplasia in the liver with gray scale and power Doppler sonography. In all patients Levovist was administered intravenously in a concentration of 300 to 400 mg galactose per milliliter. Visualization of the feeding vessels and the vascularity of the lesions were evaluated, and the resistive indices in the feeders and the hepatic arteries were assessed. In comparison with unenhanced power Doppler sonography, echo-enhanced power Doppler sonography yields a higher sensitivity in the detection of the feeding artery (97% versus 82%) in focal nodular hyperplasia and in the depiction of the radial vascular architecture in such lesions, especially those located in the left lobe of the liver. Lesions less than 3 cm in diameter do not consistently show a characteristic vascular architecture with echo-enhanced Doppler sonography. The resistive index of the tumor-feeding artery (mean, 0.51 +/- 0.09) is significantly (P < 0.0001) lower than that of the hepatic artery (mean, 0.65 +/- 0.06) and decreases as the size of the focal nodular hyperplasia increases. The administration of Levovist may improve the signal-to-noise ratio and thus visualization of the vascular architecture in focal nodular hyperplasia. Lesions located in the left lobe of the liver, which commonly are subject to disturbing motion artifacts in color Doppler sonography, will significantly benefit from the administration of Levovist. Echo-enhanced power Doppler sonography, however, is not capable of depicting a characteristic vascular pattern in small (< or = 3 cm) lesions of focal nodular hyperplasia that would guarantee a specific diagnosis.