Christian Stroszczynski

Time-domain optical mammography: initial clinical results on detection and characterization of breast tumors.

Mammograms of 35 patients suspected of breast cancer were taken along craniocaudal and mediolateral projections with a dual-wavelength scanning laser pulse mammograph measuring time-resolved transmittance. Among 26 tumors known from routine clinical diagnostics, 17 tumors were detected retrospectively in optical mammograms. Effective tumor optical properties derived from a homogeneous model were used to deduce physiological information. All tumors exhibited increased total hemoglobin concentration and decreased or unchanged blood oxygen saturation compared with surrounding healthy tissue. Scatter plots based on a pixelwise analysis of individual mammograms were introduced and applied to represent corelations between characteristic quantities derived from measured distributions of times of flight of photons.

Treatment of Thoracic Anastomotic Leaks After Esophagectomy With Self-expanding Plastic Stents

Objective:To evaluate the efficacy of a self-expanding plastic stent in the treatment of thoracic leaks after esophagectomy for cancer. Summary Background Data:Anastomotic leaks are a major cause of morbidity and mortality after esophageal resection. Treatment options range from aggressive surgery to conservative management, but there remains much controversy on the best treatment. Methods:Over a 6-year period (1998–2003), esophagogastric leaks were observed in 19 of 204 patients (9.3%) after esophagectomy. Between 1998 and 2000, anastomotic leaks were managed by reexploration (n = 7) or by conservative treatment (n = 3). Since 2001, insertion of self-expanding plastic stents was performed for all anastomotic leaks (n = 9). The short-term efficacy and long-term outcome of both treatments were analyzed. Results:Self-expanding plastic stents were successfully placed in all patients without procedure-related morbidity. Immediate leak occlusion was obtained in 8 of 9 patients. The mean healing time (time to stent removal) was 29 days. Compared with the conventional treatment group, patients who were treated with stents had earlier oral intake (11 days versus 23 days), a less extensive intensive care course (25 days versus 47 days), and shorter hospital stay (35 days versus 57 days). In-hospital mortality was 0% (0 of 9 patients) in the stent group and 20% (2 of 10 patients) in the other group. After a mean follow-up of 12 months, none of the patients developed a stricture after stenting, but a stricture occurred in 1 patient after conservative treatment. Conclusions:Self-expanding plastic stents can reduce leak-related morbidity and mortality after esophagectomy and may be considered a cost-effective treatment alternative.

Detection of Recurrent Pancreatic Cancer: Comparison of FDG-PET with CT/MRI

Objective: To determine the value of fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for the detection of recurrent pancreatic cancer in comparison to computed tomography (CT) and magnetic resonance imaging (MRI). Methods: Thirty-one patients with suspected recurrence after surgery were included. Inclusion criteria were sudden weight loss, pain or increased CA 19-9 levels. FDG-PET was performed in all patients. After visual analysis, maximal standardized uptake values (SUVmax) were determined by placing regions of interest on the pancreas bed. Additionally, all patients underwent contrast-enhanced multidetector CT (n = 14) or MR (n = 17) imaging. Positive findings at FDG-PET or CT/MRI were compared to follow-up. Results: All patients relapsed. Of 25 patients with local recurrences upon follow-up, initial imaging suggested relapse in 23 patients. Of these, FDG-PET detected 96% (22/23) and CT/MRI 39% (9/23). Local SUVmax ranged from 2.26 to 16.9 (mean, 6.06). Among 12 liver metastases, FDG-PET detected 42% (5/12). CT/MRI detected 92% (11/12) correctly. Moreover, 7/9 abdominal lesions were malignant upon follow-up of which FDG-PET detected 7/7 and CT/MR detected none. Additionally, FDG-PET detected extra-abdominal metastases in 2 patients. Conclusion: In patients suspected of pancreatic cancer relapse; FDG-PET reliably detected local recurrences, whereas CT/MRI was more sensitive for the detection of hepatic metastases. Furthermore, FDG-PET proved to be advantageous for the detection of nonlocoregional and extra-abdominal recurrences.

Intestinal ischemia: current treatment concepts

PurposeMesenteric ischemia is a condition well-known among physicians treating patients with abdominal symptoms. Even so, mortality rates have not decreased significantly over the last decades. The purpose of this article is to review current treatment concepts of acute and chronic mesenteric ischemia.ResultsEarly diagnosis is one of the most important features that determine a patient’s prognosis. Conventional angiography and multidetector computed tomography are therefore appropriate to quickly diagnose mesenteric ischemia, the latter being commonly more available. Once a patient presents with signs of peritonitis, instant laparotomy is indicated, and infarcted bowel segments need to be resected, followed by a second-look operation if necessary. If bowel necrosis is clinically not suspected, different approaches should be applied according to source and nature of mesenteric ischemia. Besides established surgical treatment concepts, more and more interventional procedures are developed and evaluated. However, superiority of these new techniques could only be shown for selected patient groups so far. In chronic mesenteric ischemia, interventional approaches seem to be an attractive alternative in patients who are in a condition too bad to undergo surgery. Patients with colonic ischemia are treated best in a conservative manner and by resolving the underlying cause, if identified.ConclusionPatients with acute mesenteric ischemia are still at highest risk for a fatal course of disease. New diagnostic and therapeutic developments have not been tested in larger studies yet, neither has any of these methods led to an increased survival in studies published so far. Taken together, mesenteric ischemia requires high awareness, earliest possible diagnosis, and treatment by an experienced interdisciplinary team of gastroenterologists, radiologists, and surgeons.

Assessment of Clinical Signs of Liver Cirrhosis Using T1 Mapping on Gd-EOB-DTPA-Enhanced 3T MRI

Objectives To assess the differences between normal and cirrhotic livers by means of T1 mapping of liver parenchyma on gadoxetic acid (Gd-EOB-DTPA)-enhanced 3 Tesla (3T) MR imaging (MRI). Methods 162 patients with normal (n = 96) and cirrhotic livers (n = 66; Child-Pugh class A, n = 30; B, n = 28; C, n = 8) underwent Gd-EOB-DTPA-enhanced 3T MRI. To obtain T1 maps, two TurboFLASH sequences (TI = 400 ms and 1000 ms) before and 20 min after Gd-EOB-DTPA administration were acquired. T1 relaxation times of the liver and the reduction rate between pre- and post-contrast enhancement images were measured. Results The T1 relaxation times for Gd-EOB-DTPA-enhanced MRI showed significant differences between patients with normal liver function and patients with Child-Pugh class A, B, and C (p < 0.001). The T1 relaxation times showed a constant significant increase from Child-Pugh class A up to class C (Child-Pugh class A, 335 ms ± 80 ms; B, 431 ms ± 75 ms; C, 557 ms ± 99 ms; Child-Pugh A to B, p < 0.001; Child-Pugh A to C, p < 0.001; Child-Pugh B to C, p < 0.001) and a constant decrease of the reduction rate of T1 relaxation times (Child-Pugh class A, 57.1% ± 8.8%; B, 44.3% ± 10.2%, C, 29.9% ± 6.9%; Child-Pugh A to B, p < 0.001; Child-Pugh A to C,p < 0.001; Child-Pugh B to C, p < 0.001). Conclusion Gd-EOB-DTPA-enhanced T1 mapping of the liver parenchyma may present a useful method for determining severity of liver cirrhosis.

Apparent diffusion coefficient measurements of the pancreas, pancreas carcinoma, and mass-forming focal pancreatitis

Background Mass-forming focal pancreatitis (FP) may mimic pancreatic cancer (PC) on magnetic resonance (MR) imaging, and the preoperative differential diagnosis is often difficult. Recently, the usefulness of diffusion-weighted imaging (DWI) in the diagnosis of pancreatic cancer has been reported in several studies. Purpose To investigate if apparent diffusion coefficient (ADC) measurements based on diffusion-weighted echo-planar imaging (DW-EPI) may distinguish between normal pancreas parenchyma, mass-forming focal pancreatitis, and pancreas carcinoma. Material and Methods MRI was performed on 64 patients: 24 with pancreas carcinoma (PC), 20 with mass-forming focal pancreatitis (FP), three patients with other focal pancreatic disease as well as 17 controls without any known pancreatic disease. Diffusion-weighted sequence with ADC maps and T2-weighted sequence for anatomical information was performed. Apparent diffusion coefficient (ADC) maps were automatically created and analyzed using a dedicated user interface. In the group with pancreas disease the abnormal parenchyma was detected by using T1- and T2-weighted images and the region of interest (ROI) was transferred exactly to the ADC map and the coefficients were registered. In the control group the ROI was set to the head of the pancreas followed by a similar registration of the ADCs. Results ADC values for mass-forming FP and PC differed significantly from ADC values for normal pancreas parenchyma (P = 0.001/P = 0.002). Mean ADC values for mass-forming FP were 0.69 ± 0.18 × 10−3 mm2/s. ADC values for PC were 0.78 ± 0.11 × 10−3 mm2/s, compared to ADC values of 0.17 ± 0.06 × 10−3 mm2/s in the control group. However there was no significant difference in ADCs between PC and mass-forming FP (P = 0.15). Conclusion ADC measurements clearly differentiated between normal pancreatic tissue and abnormal pancreas parenchyma (PC and mass-forming FP). However there is an overlap in values of PC and mass-forming FP, with the consequent problem of their correct identification.

Impact of liver cirrhosis on liver enhancement at Gd-EOB-DTPA enhanced MRI at 3 Tesla

PURPOSE The purpose of this study was to assess differences in enhancement effects of liver parenchyma between normal and cirrhotic livers on dynamic, Gd-EOB-DTPA enhanced MRI at 3T. MATERIALS AND METHODS 93 patients with normal (n=54) and cirrhotic liver (n=39; Child-Pugh class A, n=18; B, n=16; C, n=5) underwent contrast-enhanced MRI with liver specific contrast media at 3T. T1-weighted volume interpolated breath hold examination (VIBE) sequences with fat suppression were acquired before contrast injection, in the arterial phase (AP), in the late arterial phase (LAP), in the portal venous phase (PVP), and in the hepatobiliary phase (HBP) after 20 min. The relative enhancement (RE) of the signal intensity of the liver parenchyma was calculated for all phases. RESULTS Mean RE was significantly different among all evaluated groups in the hepatobiliary phase and with increasing severity of liver cirrhosis, a decreasing, but still significant reduction of RE could be shown. Phase depending changes of RE for each group were observed. In case of non-cirrhotic liver or Child-Pugh Score A cirrhosis mean RE showed a significant increase between AP, LAP, PVP and HBP. For Child-Pugh B+C cirrhosis RE increased until PVP, however, there was no change in case of B cirrhosis (p=0.501) and significantly reduced in case of C cirrhosis (p=0.043) during HBP. CONCLUSION RE of liver parenchyma is negatively affected by increased severity of liver cirrhosis, therefore diagnostic value of HBP could be limited in case of Child Pugh B+C cirrhosis.

Image fusion of contrast enhanced ultrasound (CEUS) with computed tomography (CT) or magnetic resonance imaging (MRI) using volume navigation for detection, characterization and planning of therapeutic interventions of liver tumors

AIM To evaluate, whether image fusion of contrast enhanced ultrasound (CEUS) with CT or MRI affects the diagnosis and characterization of liver lesions or the therapeutic strategy of surgical or interventional procedures compared to the preliminary diagnosis. MATERIAL AND METHODS In a retrospective study the image fusion scans of CEUS with contrast enhanced CT or MRI of 100 patients (71 male, mean age 59 years, 0.3-85 years) with benign or malignant liver lesions were evaluated. Fundamental B-scan, color Doppler imaging and CEUS were performed in all patients by an experienced examiner using a multifrequency convex transducer (1-5 MHz, LOGIQ 9/GE) and volume navigation (Vnav). After a bolus injections of up to 2.4 ml SonoVue® (BRACCO, Italy) digital raw data was stored as cine-loops up to 5 min. In 74 patients, CEUS was fused with a pre-existing ceCT, in 26 patients a ceMRI was used. RESULTS In all 100 patients (100%) the image quality in all modalities (ceCT, ceMRI and CEUS) was excellent or with only minor diagnostic limitations. Regarding the number of lesions revealed in image fusion of CEUS/ceCT/ceMRI and the preceding diagnostic method, concordant results were found in 84 patients. In 12 patients, additional lesions were found using fusion imaging causing subsequently a change of the therapeutical strategy. In 15 out of 21 patients with either concordant or discordant results regarding the number of lesions, image fusion allowed a definite diagnosis due to a continuous documentation of the microcirculation of the tumor and its contrast enhancement. A significant coherency (p < 0.05) among image fusion with either ceCT or ceMRI and CEUS and a subsequent change of therapeutic strategy was found. CONCLUSION Image fusion with volume navigation (VNav) of CEUS with ceCT or ceMRI frequently allows a definite localization and diagnosis of hepatic lesions in patients with primary hepatic carcinoma or metastatic diseases. This might cause a change of the therapeutic strategy in many patients with hepatic lesions.

MRI-based estimation of liver function: Gd-EOB-DTPA-enhanced T1 relaxometry of 3T vs. the MELD score

Gd-EOB-DTPA is a hepatocyte-specific MRI contrast agent. Due to its hepatocyte-specific uptake and paramagnetic properties, functioning areas of the liver exhibit shortening of the T1 relaxation time. We report the potential use of T1 relaxometry of the liver with Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for estimating the liver function as expressed by the MELD score. 3 T MRI relaxometry was performed before and 20 min after Gd-EOB-DTPA administration. A strong correlation between changes in the T1 relaxometry and the extent of liver disease, expressed by the MELD score, was documented. Reduced liver function correlates with decreased Gd-EOB-DTPA accumulation in the hepatocytes during the hepatobiliary phase. MRI-based T1 relaxometry with Gd-EOB-DTPA may be a useful method for assessing overall and segmental liver function.

Laser-induced thermotherapy (LITT) of liver metastases: MR-guided percutaneous insertion of an MRI-compatible irrigated microcatheter system using a closed high-field unit.

To evaluate the efficacy and safety of a new MRI‐compatible irrigated laser microcatheter system for thermal ablation of liver metastases.