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Biomedical subjects

F Kammerhuber

Publications and source records attributed to F Kammerhuber.

At least 19 recordsLinked to original sources
PubMed1998

[Criteria for ultrasound differentiation of small angiomyolipomas (< or = 3 cm) and renal cell carcinomas].

PURPOSE: The purpose of this prospective study was to analyze whether ultrasound (US) features are helpful for the differentiation and characterization of small solid (< or = 3 cm) renal masses. MATERIALS AND METHODS: 70 small solid (< or = 3 cm) renal masses were evaluated sonographically with respect to size, location, echogenicity, homogeneity, shadowing, hypoechoic rim, and cystic regions. In addition, all masses were evaluated with spiral-computed tomography (CT). A diagnosis of angiomyolipoma (AML) was made when a lesion contained components with attenuation of fat (> -10 HU). The amount of fat and soft tissue of an AML detected on CT was correlated with the presence of shadowing seen on sonography. RESULTS: 10 (29%) of the 35 renal cell carcinomas (RCC) were hyperechoic to renal parenchyma, but no RCC was as echogenic as the renal sinus fat. Acoustic shadowing was only observed in AML. 11 (34%) AML with shadowing tended to have a larger amount of soft tissue. A hypoechoic rim and cystic regions were only found in RCC. 14 of 35 (40%) RCC showed a hypoechoic rim. Cystic regions were found in 12 of the 35 RCC (34%). CONCLUSIONS: Renal cell carcinomas display a broad range of echogenicities indicating that small RCC (< or = 3 cm) and AML are not definitely distinguishable by their type of echogenicity. The presence of shadowing, a hypoechoic rim, and cystic regions enable differentiation of small (< or = 3 cm) AML from RCC with a high specificity. Accordingly, sonography has the potential to characterize small (< or = 3 cm) hyperechoic renal masses, with high specificity. However, the low sensitivity of these US features may require a CT for accurate diagnosis.

Adult↗
PubMed1997

Functional magnetic resonance imaging of human renal allografts during the post-transplant period: preliminary observations.

Graft dysfunction is a common occurrence during the first weeks following renal transplantation. The current study was designed to evaluate the potential of renal magnetic resonance (MR) perfusion imaging to differentiate acute allograft rejection (AAR) from acute tubular necrosis (ATN) during the post-transplant period. Twenty-three consecutive patients with clinically suspected ATN and/or AAR and eight consecutive control patients (asymptomatic, serum creatinine concentration < 1.5 mg/dL) underwent MR perfusion imaging of the renal allograft within 64 days after transplantation. Histopathology was obtained in all cases with clinical suspicion of ATN or AAR. Sixty sequential fast gradient-recalled-echo MR images were acquired in each patient after intravenous administration of gadolinium-DTPA (0.1 mmol/kg). Histopathology revealed 6 patients with pure AAR, 4 patients with a combination of AAR and ATN, 12 patients with ATN and 1 patient with normal findings. Kidney graft recipients with normal renal function showed a moderate increase in signal intensity (SI) of the renal cortex and medulla after administration of contrast agent followed by an immediate and short decrease in SI of the medulla (biphasic medullary enhancement pattern). The increase in cortical SI of patients with AAR was significantly smaller (61 +/- 4% increase above baseline) than that measured in normal allografts (136 +/- 9% increase above baseline) (p < 0.05) and patients with ATN (129 +/- 3% increase above baseline) (p < .05). Patients with ATN had a slightly delayed and diminished cortical enhancement and an uniphasic and lesser medullary enhancement pattern compared to that observed in normal allografts (p < 0.05). A close correlation (r = 0.72) was found between serum creatinine concentration levels and changes in SI. Thus, MR imaging results and histopathology were in agreement in 22 of 23 patients (96%). MR perfusion imaging of renal allografts can be used to noninvasively differentiate ATN from AAR during the post-transplant period, and may also be helpful in cases were covert AAR is superimposing ATN during a phase of anuria. Patients with ATN can be separated from normals in the majority of cases as reflected by an uniphasic medullary enhancement pattern.

Adult↗
PubMed1997

Multiphasic helical CT of the kidney: increased conspicuity for detection and characterization of small (< 3-cm) renal masses.

PURPOSE: To evaluate the potential of thin-section multiphasic helical computed tomography (CT) in the detection and characterization of small (< 3.0-cm) renal masses. MATERIALS AND METHODS: Identically collimated helical CT of the kidney was performed before and after administration of contrast material in 93 patients with small renal masses. Helical CT scans were obtained during the corticomedullary and nephrographic phases. Differences between attenuation of the lesion and that of the kidney were measured quantitatively. The presence of a mass or absence of disease was confirmed with clinical, imaging, and histologic findings. RESULTS: The number of masses smaller than 3.0 cm detected on corticomedullary-phase scans (n = 211) was statistically significantly fewer than those on nephrographic-phase scans (n = 295) (P < .01). Mean differences in enhancement between the renal cortex and masses were 148 HU +/- 54 and 137 HU +/- 44 during the corticomedullary and nephrographic phases, respectively, and the difference in attenuation of the renal medulla and that of the masses was statistically significantly greater during the nephrographic phase (P < .01). False-positive results (n = 9) occurred only on corticomedullary-phase scans because of lack of enhancement of the renal medulla. CONCLUSION: Nephrographic-phase scans enabled greater lesion detection and better characterization of small renal masses than corticomedullary-phase scans. Nephrographic-phase scans should be obtained when only monophasic scanning is used to detect small renal masses.

Adult↗
PubMed1997

Quantitative CT evaluation of adrenal gland masses: a step forward in the differentiation between adenomas and nonadenomas?

PURPOSE: To assess the attenuation of the adrenal gland with computed tomography (CT) before and after multiple phases of contrast enhancement in both control subjects and patients with adenomas and nonadenomas. MATERIALS AND METHODS: Seventy-two patients with 78 adrenal masses (41 adenomas, 37 nonadenomas) underwent helical CT. Forty subjects served as controls. Unenhanced CT was performed followed by enhanced CT at 30, 60, 90, and 180 seconds and 30 minutes. RESULTS: At unenhanced CT, mean attenuation was 4 HU +/- 16 for adenomas compared with 37 HU +/- 12 for the nonadenomas (P < .001) and 24 HU +/- 3 for normal glands. Although the mean attenuation of nonademonas was significantly greater than that of adenomas on 60- and 90-second scans (P < .001), there was greater overlap in attenuation of the adenomas and nonadenomas than on unenhanced images. At 180 seconds, nonadenomas had higher attenuation than adenomas (73 HU +/- 17 vs 41 HU +/- 18; P < .001). At 30 minutes, all adenomas had attenuation less than 37 HU, whereas all nonadenomas had attenuation greater than 41 HU. CONCLUSION: Delayed-enhanced CT scans obtained 30 minutes after administration of contrast material can enable differentiation of adenomas and nonadenomas.

Adenoma↗
PubMed1997

Testicular blood flow in boys as assessed at color Doppler and power Doppler sonography.

PURPOSE: To investigate at which age testicular blood flow can be demonstrated consistently by color Doppler sonography and power Doppler sonography. MATERIALS AND METHODS: In this prospective study, 172 normal testes of 86 boys (age range, 4 days to 15 years) were examined with gray-scale ultrasound, color Doppler sonography, and power Doppler sonography. Presence of supratesticular and capsular vessels was determined, testicular volumes were assessed, and intratesticular vessels were quantified by using a semiquantitative score. RESULTS: Supratesticular and capsular vessels were always detectable. Demonstration of intratesticular vessels was inconsistent until 8 years of age at power Doppler sonography and until 12 years of age at color Doppler sonography. Power Doppler sonography depicted more vessels than did color Doppler sonography in 37 (22%) testes (P = .001), and it depicted vessels in 13 (25%) of 51 testes in which color Doppler sonography could not (P = .0002). Correlation between the number of visible intratesticular vessels was slightly closer with age than with testicular volume (r = .59, r = .55 for color Doppler sonography and power Doppler sonography, respectively). CONCLUSION: Intratesticular blood flow can be detected more sensitively and more consistently from a younger age on with power Doppler sonography than with color Doppler sonography.

Adolescent↗
PubMed1997

Sonography of acute cholecystitis: comparison of color and power Doppler sonography in detecting a hypervascularized gallbladder wall.

OBJECTIVE: We evaluated the sensitivity and specificity of power Doppler sonography compared with conventional color Doppler sonography and gray-scale sonography in diagnosing patients with acute cholecystitis. SUBJECTS AND METHODS: Seventy-six patients with right upper quadrant pain and 72 healthy volunteers underwent gray-scale sonography, conventional color Doppler sonography, and power Doppler sonography of the gallbladder. The vascularity of the gallbladder wall was scored on a scale of 0 to +3. Histology revealed acute cholecystitis in 55 patients. Histologic specimens and clinical workups showed that the remaining 21 patients suffered from other diseases. RESULTS: Sensitive sonographic features such as the positive Murphy's sign (in 96% of patients with acute cholecystitis), calculi (95%), and a thickened gallbladder wall (73%) lacked specificity (71%, 38%, 67%, respectively) for diagnosing acute cholecystitis. In our study, the sensitivity of power Doppler sonography was 95% compared with 33% for color Doppler sonography in revealing a hypervascularized gallbladder wall. Power Doppler sonography revealed hyperemia within a nonthickened gallbladder wall in four patients with surgically proven acute cholecystitis. Specificity of power Doppler sonography was 86% compared with 95% for conventional color Doppler sonography. False-positive results with power Doppler sonography were caused by pancreatitis, duodenal ulcer, and gallbladder carcinoma. Interobserver variability seemed to play no significant role. No intramural hypervascularity was detected in the volunteer group. In four (4%) of 89 symptomatic patients we could not use power Doppler sonography because of the patients noncompliance. Mean values of the resistive index assessed within intramural vessels of the gallbladder showed no significant differences (p < .001) between patients with acute cholecystitis (0.73) and patients with other diseases (0.71). CONCLUSIONS: Although the sensitivity of power Doppler sonography in diagnosing acute cholecystitis was similar to that of gray-scale sonography, the specificity of power Doppler sonography was significantly higher, which may substantially improve diagnostic confidence. However, the high susceptibility of power Doppler sonography to motion artifacts makes appropriate adjustment of technical parameters much more relevant than with other sonographic imaging. The resistive index within intramural vessels has no clinical use in the diagnosis of acute cholecystitis.

Acute Disease↗
PubMed1997

Detection of pulmonary nodules with helical CT: comparison of cine and film-based viewing.

OBJECTIVE: The purpose of our study was to determine whether cine viewing of helical CT scans of the chest improves the detection of pulmonary nodules in patients with known extrathoracic malignancy. SUBJECTS AND METHODS: Identical helical CT studies of the chest of 60 patients with known extrathoracic malignancy were reviewed for detection of pulmonary nodules. Four radiologists interpreted the helical CT studies. Pulmonary nodules were divided into four groups according to maximum diameter: group 1, nodules smaller than or equal to 5 mm; group 2, nodules larger than 5 mm but smaller than or equal to 10 mm; group 3, nodules larger than 10 mm but smaller than or equal to 20 mm; group 4, nodules larger than 20 mm. Interpreters also assigned a lesion conspicuity score of pulmonary nodules based on a four-point scale: one point for poor visibility, two points for adequate visibility, three points for good visibility, and four points for excellent visibility. Static film-based images printed on a laser printer were viewed on a light box. Cine viewing of helical CT scans from the same examinations was done on a commercially available workstation. The number, diameter, and conspicuity scores of pulmonary nodules detected at lung window settings were documented. RESULTS: Interpreters saw 266 nodules on cine viewing, whereas 237 nodules were seen with static film-based viewing. A significantly higher percentage of nodules that were smaller than or equal to 5 mm in diameter was found with cine viewing (n = 106) than with static film-based viewing (n = 81) (p < .05). Cine viewing (n = 105) also allowed a slightly but not significantly higher detection rate of nodules that were larger than 5 mm but smaller than or equal to 10 mm in diameter than did static film-based viewing (n = 101). We found no differences between cine (n = 55) and static film-based viewing (n = 55) in the detection of pulmonary nodules that were larger than 10 mm in diameter. The mean conspicuity score of nodules was significantly higher with cine viewing (2.9 +/- 0.2) than with film-based viewing (2.4 +/- 0.2) (p < .05). CONCLUSION: Cine viewing of helical CT scans significantly increases the detection rate of pulmonary nodules that are smaller than or equal to 5 mm in diameter. However, we found no significant difference between cine and film-based viewing in the detection rate of pulmonary nodules that were larger than 5 mm in diameter. The advantages of cine viewing may be attributed to both the larger image size and the ability to scroll through images for improved differentiation between vessels and nodules.

Female↗
PubMed1996

[Detection of perfusion of kidney transplants. Comparison between color-coded and amplitude-coded Doppler ultrasound].

OBJECTIVE: To evaluate the efficiency of colour Doppler energy (CDE) in comparison to conventional colour Doppler sonography (CDI) in the detection of renal blood flow signals in asymptomatic patients after renal transplantation. SUBJECTS AND METHODS: Fifteen asymptomatic volunteer patients after renal transplantation were examined with CDI and CDE. The examination parameters were kept constant; only the Doppler-receiver gain was varied. Assessment and comparison of blood flow signals were obtained with a self defined score system. RESULTS: CDI showed Doppler signals in the main stem vessels, segmental and interlobar vessels in all patients; in the arcuate arteries blood flow signals were detected in only 11 of 15 patients. There was no Doppler signal in peripherally located medullary and cortical vessels. CDE showed blood flow signals in the main stem, segmental and interlobar vessels and additionally in the arcuate, interlobular and medullary as well as in the cortical vessels in all patients. CONCLUSION: CDE is more sensitive than CDI and improves the detection of blood flow signals in peripheral medullary and cortical vessels of renal transplants.

Adult↗
PubMed1991

Anti-carcinoembryonic antigen immunoscintigraphy (technetium-99m-monoclonal antibody BW 431/26) and serum CEA levels in patients with suspected primary and recurrent colorectal carcinoma.

This study comprises a total of 141 patients with suspected primary and recurrent colorectal carcinomas, in whom immunoscintigraphy with 99mTc-Mab BW 431/26 was performed. Whole-body scans were done 5.5 hr and SPECT imaging of the abdominal region was done at 6 and 24 hr postinjection of 1100 MBq 99mTc-labeled Mab (1 mg). In the course of primary tumor identification (n = 65), sensitivity of anti-CEA immunoscintigraphy was 95%, specificity 91%. In the diagnosis of early recurrences (n = 76), immunoscintigraphy was the method of choice to clarify the problem (sensitivity 94%; specificity 86%). Overall sensitivity of immunoscintigraphy in patients with suspected colorectal carcinomas and early recurrences was 95%, specificity 88%. Human anti-mouse antibodies were found in 29% (80% predominantly anti-isotypic, 20% predominantly anti-idiotypic). In contrast to anti-CEA immunoscintigraphy, the results of serum CEA levels were rather disappointing. Only 18 out of the 43 surgically verified primary colorectal carcinomas and 17 out of 32 patients with recurrences showed elevated serum CEA levels. In our clinical experience with this 99mTc-labeled anti-CEA antibody, immunoscintigraphy can play an important role in the identification of early colorectal recurrences and in postoperative colorectal cancer patients it should be performed in cases with unclear transmission computed tomography.

Adult↗
PubMed1990

Localization of mediastinal parathyroid adenoma by T1-201 scintiscan and SPECT.

A 64-year-old female patient was admitted to our department for fatigue, pain in the right upper abdomen, obstipation, and meteorism. The laboratory findings showed total calcium and ionized calcium elevated, phosphate close to lower limit, and parathyroid hormone increased. T1-201/Tc-99m subtraction scintiscan of the neck and upper mediastinal region did not give any evidence of isolated enhanced uptake suggesting the presence of parathyroid adenoma. After further increases in calcium and parathyroid hormone level T1-201 whole-body scan and single photon emission computed tomography of the thoracic region were performed. These revealed a circumscribed T1-201 uptake in the mediastinum immediately cranial ventral to the heart base. The postcontrast transmission computed tomography of this area confirmed the finding of the T1-201 scintigraphy with a 4 x 3 x 2 cm tumor. After sternotomy and surgical removal of the mediastinal parathyroid adenoma (chief cell adenoma), calcium and parathyroid hormone levels returned to normal values.

Adenoma↗