Acta Radiologica

Purpose: To evaluate the biliary enhancement dynamics of the two gadolinium chelates Gd-BOPTA (MultiHance®) and Gd-EOB-DTPA (Primovist®) in normal healthy subjects.

Material and Methods: Ten healthy volunteers were evaluated with both agents by magnetic resonance (MR) imaging at 1.5T using a breath-hold gradient-echo T1-weighted VIBE sequence. The relative signal intensity (SI) differences between the common hepatic duct (CHD) and liver parenchyma were measured before and 10, 20, 30, 40, 130, 240, and 300 min after contrast medium injection.

Results: Biliary enhancement was obvious 10 min post-injection for Gd-EOB-DTPA and was noted at 20 min for Gd-BOPTA. At 40 min delay, Gd-BOPTA reached its peak biliary enhancement, but at neither 30 nor 40 min delay was there any significant difference compared with that of Gd-EOB-DTPA. At later delays, the contrast between CHD and liver continued to increase for Gd-EOB-DTPA, whereas it decreased for Gd-BOPTA.

Conclusion: The earlier onset and longer duration of a high contrast between CHD and liver for Gd-EOB-DTPA facilitates examination of hepatobiliary excretion. Therefore, Gd-EOB-DTPA may provide adequate hepatobiliary imaging within a shorter time span than Gd-BOPTA and facilitate scheduling at the MR unit. Further studies in patients are required to compare the imaging advantages of Gd-EOB-DTPA and Gd-BOPTA in clinical practice.

Background: The choice of imaging before liver surgery is debated regarding the use of magnetic resonance (MR) imaging, computed tomography (CT), and positron emission tomography (PET). No studies have compared contrast-enhanced PET/CT with superparamagnetic iron oxide (SPIO)-enhanced MR imaging.

Purpose: To compare PET/CT with superparamagnetic iron oxide (SPIO)-enhanced MR imaging, PET, and CT in the detection of liver metastases (LM) and extrahepatic tumor from colorectal cancer (CRC).

Material and Methods: Thirty-five patients with suspected LM underwent PET/CT with a contrast-enhanced CT protocol and SPIO-enhanced MR imaging. Readers independently analyzed images from MR imaging, PET/CT, and the CT part and PET part of the PET/CT study. Imaging findings were compared with surgical and histological findings.

Results: Lesion-by-lesion sensitivity and accuracy for liver lesions was 54% and 77% for PET alone, 66% and 83% for PET/CT, 82% and 82% for SPIO-enhanced MR imaging, and 89% and 77% for CT alone, respectively. CT and SPIO-enhanced MR imaging were less specific but significantly more sensitive than PET (P<0.0001). For extrahepatic tumor, sensitivity and specificity was 83% and 96% for PET/CT and 58% and 87% for CT, respectively.

Conclusion: CT and SPIO-enhanced MR imaging are more sensitive but less specific than PET in the detection of LM. PET/CT can detect more patients with extrahepatic tumor than CT alone.

Purpose: To assess image quality and overall accuracy of 3-Tesla (3T)-sustained high-resolution magnetic resonance (MR) imaging for diagnostic preoperative workup in suspected rectal carcinoma.

Material and Methods: Twenty-three patients with suspected rectal cancer underwent unenhanced and contrast-enhanced fat-suppressed pelvic high-resolution MR imaging using a four-channel phased-array pelvic coil at 3T. Image quality, tumor stage, distance from the anorectal margin, and sphincter-saving resectability were prospectively assessed by two blinded readers. The results were correlated with clinical, surgical, and histopathologic findings.

Results: In all 23 patients, MR images were of diagnostic quality, and malignancy was correctly identified in 21 patients. The accuracy for determining sphincter-saving resectability was 100% (19/19). T stage and N stage were correctly diagnosed in 95% and 91%, respectively. MRI allowed correct identification of tumor extension and its relation to surgically relevant pelvic structures including the anorectal margin and mesorectal fascia. Transverse T2-weighted fast spin-echo images compared superiorly to all other sequences for the diagnosis of mesorectal infiltration and lymph node involvement. Moreover, transverse fat-suppressed contrast-enhanced T1-weighted images were valuable for identifying tumor infiltration, while sagittal sections were useful for the detection of longitudinal tumor extension.

Conclusion: MR imaging with phased-array receiver coils at 3T facilitated both visualization of different pathologic conditions of the rectum and accurate determination of tumor stage in rectal carcinomas. Thus, this noninvasive diagnostic approach appeared highly suitable for the assessment of patients with suspected rectal carcinoma.

MRI in Practice. Third edition. Edited by C. Westbrook, C. Kaut Roth and J. Talbot. Blackwell Publishing Ltd, Oxford, 2005. ISBN 9781405127875. 410 pages. Price paperback: USD 59.95, GBP 32.50

Purpose: To compare the mammographic features of recurrent breast cancer with those of the primary tumor and to determine whether certain mammographic features are associated with a higher risk of local recurrence after breast-conserving therapy.

Material and Methods: A retrospective review of mammograms of 421 patients who were treated with conservative surgery and radiotherapy revealed 41 recurrent tumors. Mammographic findings, location, and histopathologic characteristics were retrospectively compared between primary and recurrent tumors.

Results: Recurrent tumors were similar in mammographic appearance to primary tumors in 27 (66%) cases. Of 27 primary tumors that occurred as masses without calcifications, 19 (70%) recurred as a mass, and of the six isolated calcifications, five (83%) recurred with calcifications. Ten (53%) of the 19 recurrent masses and five (100%) of the five recurrent calcifications had morphologic features that were similar to those of the primary tumor. Ninety-two percent (11/12) of the recurrences containing microcalcifications (isolated or associated with a mass) had microcalcifications in their primary tumor. Of 27 masses that recurred, the morphology of the primary tumor was obscured in 13 (48%), ill defined in 10 (37%), and spiculated in four (15%) of the masses. Seventy-six percent (31/41) of recurrences were within the lumpectomy quadrant. In 25 (61%) cases, the histologic findings from the primary tumor and the recurrence were identical.

Conclusion: The majority of recurrent tumors appear to be mammographically similar to primary tumors. Therefore, it is important to review preoperative mammograms during follow-up of these patients. Although the study population is small, it was noted that mass with spiculated contour is associated with a lower risk for local recurrence.

We present the imaging findings of severe bilateral mammary duct ectasia in a postmenopausal woman. Mammographic, ultrasonographic, and magnetic resonance findings are described. Needle biopsy was used to confirm the diagnosis. Etiology, clinical significance, and management strategies for this lesion are discussed.

We report a 21-year-old woman with a penetrating abdominal wound. Injuries of the abdominal aorta and alimentary tract were found during emergency surgery. The patient had a follow-up computed tomography (CT) scan 3 months after surgery. Arterial-phase 16-row multidetector computed tomography (MDCT) showed a suspicious dilated vessel adjacent to the repaired aorta on 5-mm transverse images. A fistula between a lumbar artery and the inferior vena cava was clearly demonstrated on images reformatted with two- (2D) and three-dimensional (3D) techniques. The patient suffered from symptoms of high-output heart failure 8 months after surgery.

Purpose: To determine whether low-dose spiral computed tomography (LDCT) can improve the lung cancer detection rate in chronic obstructive pulmonary disease (COPD) subjects.

Material and Methods: From October 1999 to December 2003, 374 COPD patients underwent LDCT for lung carcinoma screening. All subjects with an abnormal baseline CT scan were followed with serial CT scans as part of our protocol. Follow-up was continued until the demonstration of no change over a minimum of 24 months, or resolution. Sputum samples were also obtained for cytological analysis.

Results: On the baseline spiral CT scan, 132 of 374 patients (35.2%) had at least one non-calcified nodule that required periodic follow-up with CT scans. The median follow-up time was 21 months (range 2–48 months). Of the 374 COPD subjects, nine patients with primary lung cancer (2.4%) were detected: six were squamous cell carcinomas, two were small-cell lung carcinomas (SCLC), and one was adenosquamous carcinoma. Three of the nine tumors were in stage IA, two in stage IIB, two in stage IIIA, and two were limited SCLC. Potentially curative pulmonary resection was performed in four patients, pulmonary lobectomy in three, and wedge excision in one. One subject with stage IA squamous cell carcinoma received radiotherapy, as pulmonary function was severely impaired. In addition, four patients underwent removal of benign lesions. Sputum was collected in 205 (54.8%) of 374 patients. There were 154 (75 %) metaplasia, 14 (6%) moderate dysplasia, and one (0.4%) malignant case.

Conclusion: LDCT increases early lung carcinoma detection rate in COPD patients, but pulmonary function impairment may reduce its benefit.

Purpose: To evaluate the usefulness of Doppler parameters in the differentiation between the two types of amiodarone-associated thyrotoxicosis (AAT).

Material and Methods: One hundred thirty-seven individuals were selected at our institution. They were divided into four groups: 84 normal subjects (N), 30 euthyroids taking amiodarone (A), 14 AAT type 1 patients (AAT1), and nine AAT type 2 patients (AAT2). Each AAT type was classified according to ¹³¹I uptake and clinical outcome. Blindly, the resistance and pulsatility indexes (RI, PI), systolic peak velocity, and color pixel density (CPD) were calculated.

Results: AAT1 had greater CPD than AAT2 (P = 0.02). The latter group had similar vascularization to the N and A groups (P = 0.45). The area under the receiver operating characteristic (ROC) curve showed that systolic peak velocity in the inferior thyroid arteries and CPD were the best parameters in the differentiation between AAT type 1 and AAT type 2 (Az = 0.83 and 0.84, respectively). Impedance indexes were useless.

Conclusion: Our results demonstrate that objective tests such as systolic peak velocities in the thyroid arteries and CPD are reliable parameters for differentiating between the two types of AAT.

Multidetector-Row CT of the Thorax. Edited by U. J. Schoepf. Springer-Verlag, Heidelberg, 2006. ISBN 3-540- 43774-6. 482 pages, 641 figures, 37 tables. Price hardcover: EUR 229

Background: Magnetic resonance (MR) permits quantitative flow velocity measurements that could be used to detect changes in the curve profile downstream of a high-grade stenosis.

Purpose: To assess whether MR flow measurements can be used to detect iliac artery stenoses.

Material and Methods: Contrast-enhanced magnetic resonance angiography (MRA) and quantitative flow measurements in the lower aorta and proximal femoral arteries were performed in 29 patients with suspected iliac artery stenoses. Stenoses were graded into five degrees: 0%, 1–49%, 50–74%, 75–99%, and 100% diameter reduction. The femoral artery waveforms were evaluated qualitatively by two independent reviewers regarding peak systolic velocity (PSV), aortofemoral difference in time-to-peak (ΔTTP), systolic acceleration (SA), curve-shape index (CSI), and the presence of an early diastolic flow reversal. The correlation between these parameters and the degree of stenosis was assessed.

Results: A significant correlation with degree of stenosis was observed for the qualitative flow waveform evaluations, with a high degree of interobserver agreement (κ = 0.84). A significant correlation was also found between degree of stenosis and PSV, ΔTTP, SA, CSI, and presence of diastolic flow reversal. The flow velocity pattern, however, remained unchanged, both qualitatively and quantitatively, up to a stenosis degree of at least 75%.

Conclusion: Iliac artery stenoses cause femoral artery flow waveform changes that can be detected with MRI, but only at high-grade levels.

Background: Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. One of the important diagnostic procedures to recognize reperfusion failure is contrast-enhanced computed tomography or magnetic resonance imaging.

Purpose: To examine the additional effect of contrast media (iomeprol and gadopentetate dimeglumine) on hepatic microcirculation and hepatic cellular damage in the phase of early ischemia/reperfusion injury of the rat liver.

Material and Methods: The partial warm ischemia-reperfusion injury model of rat liver was used. Microcirculation and leukocyte–endothelium interaction were measured by intravital microscopy. Hepatic cellular damage was indicated by liver enzyme activity in the sera. The evaluation parameters were measured at baseline and at 30, 60, and 90 min after reperfusion. The contrast media (iomeprol group, n = 6; gadopentetate dimeglumine group, n = 6) or Ringer's solution (control group, n = 8) were applied after 30 min of reperfusion.

Results: No additional injury to the ischemia/reperfusion injury of the liver after intravenous application of radiographic contrast media was found. Some protective effect was even recorded after application of iodinated contrast media.

Conclusion: The use of contrast media during diagnostic procedure of the liver seems to be relatively safe, even in the stage of early reperfusion after liver transplantation.

Background: In the heart, the creatine kinase system plays an important role in energy reserves, and myocardial energy production essentially depends upon fatty acid metabolism.

Purpose: To examine myocardial creatine (CR) concentration and altered cardiac fatty acid metabolism in various forms of heart disease.

Material and Methods: Myocardial CR concentration of the septum was measured by gated ¹H magnetic resonance spectroscopy (MRS), applying a point-resolved spectroscopy (PRESS) sequence in 34 patients with heart disease. Of these patients, 14 underwent ¹²³I BMIPP (radioactive fatty acid analogue) myocardial scintigraphy to evaluate myocardial fatty acid metabolism. Cardiac ¹²³I BMIPP uptake was calculated as the heart-to-mediastinum count ratio.

Results: Myocardial CR concentration correlated positively with the left ventricular ejection fraction (LVEF) by echocardiography (R = 0.61, P<0.001, n = 34), suggesting that the degree of reduced CR is related to the severity of contractile dysfunction. Cardiac ¹²³I BMIPP uptake also correlated positively with LVEF (initial image, R = 0.60, P<0.05; delayed image, R = 0.63, P<0.05; n = 14). There was a significant correlation between myocardial CR and cardiac ¹²³I BMIPP uptake (initial image, R = 0.77, P<0.01; delayed image, R = 0.82, P<0.001; n = 14).

Conclusion: Our study suggests an association between CR depletion and impaired fatty acid metabolism in various forms of heart diseases.

Purpose: To evaluate the detection and the size of focal patellar cartilage lesions in T2 mapping as compared to standard clinical magnetic resonance imaging (MRI) at 1.5T.

Material and Methods: Fifty-five consecutive clinical patients referred to knee MRI were imaged both with a standard knee MRI protocol (proton-density-weighted sagittal and axial series, T2-weighted sagittal and coronal series, and T1-weighted coronal series) and with an axial multislice multi-echo spin-echo measurement to determine the T2 relaxation time of the patellar cartilage. MR images and T2 maps of patellar cartilage were evaluated for focal lesions. The lesions were evaluated for lesion width (mm), lesion depth (1/3, 2/3, or 3/3 of cartilage thickness), and T2 value (20–40 ms, 40–60 ms, or 60–80 ms) based on visual evaluation.

Results: Altogether, 36 focal patellar cartilage lesions were detected from 20 human subjects (11 male, nine female, mean age 40±15 years). Twenty-eight lesions were detected both on MRI and T2 maps, while eight lesions were only visible on T2 maps. Cartilage lesions were significantly wider (P = 0.001) and thicker (P<0.001) on T2 maps as compared to standard knee MRI. Most lesions [27] had moderately (T2 40–60 ms) increased T2 values, while two lesions had slightly (T2 20–40 ms) and seven lesions remarkably (T2 60–80 ms) increased T2 relaxation times.

Conclusion: T2 mapping of articular cartilage is feasible in the clinical setting and may reveal early cartilage lesions not visible with standard clinical MRI.

Purpose: To assess multidetector computed tomography (MDCT) findings in facial trauma in adults who accidentally fall from heights.

Material and Methods: Of the MDCT scans of 2413 cases requested by emergency-room physicians for suspected facial injury, 155 (age 15.3–76.7, mean 42.0 years; 134 male, 21 female) met the criteria of falling from heights. These were reviewed by two researchers by consensus.

Results: Of these 155, 118 (104 male, 14 female) had 247 fractures, while 37 had no fracture. The fractures were classified into 13 categories, the zygomatic complex being the region most frequently involved. Mean falling height, known in 132 of 155 cases, was 5.7 m (range 0.4–25) in all, 6.0 m (0.4–25) in those suffering a fracture, and 5.0 m (range 0.4–13) in those without a fracture. Patients with Le Fort II, Le Fort III, or frontal bone fractures had fallen higher and frequently had associated skull base fractures, but with considerable overlap in falling heights. Zygomatic arch and nasal bone fractures rarely occurred solitarily.

Conclusion: In a fall-from-height injury, nasal bone and zygomatic arch fractures indicate the presence of more severe fractures. Height cannot solely predict injury probability. Clear sinus sign is a valuable aid in assessing midface trauma in falls from heights.

Background: Thin-section diffusion-weighted imaging (DWI) is known to improve lesion detectability, with long imaging time as a drawback. Parallel imaging (PI) is a technique that takes advantage of spatial sensitivity information inherent in an array of multiple-receiver surface coils to partially replace time-consuming spatial encoding and reduce imaging time.

Purpose: To prospectively evaluate a 3-mm-thin-section DWI technique combined with PI by means of qualitative and quantitative measurements.

Material and Methods: 30 patients underwent conventional echo-planar (EPI) DWI (5-mm section thickness, 1-mm intersection gap) without parallel imaging, and thin-section EPI-DWI with PI (3-mm section thickness, 0-mm intersection gap) for a b value of 1000 s/mm², with an imaging time of 40 and 80 s, respectively. Signal-to-noise ratio (SNR), relative signal intensity (rSI), and apparent diffusion coefficient (ADC) values were measured over a lesion-free cerebral region on both series by two radiologists. A quality score was assigned for each set of images to assess the image quality. When a brain lesion was present, contrast-to-noise ratio (CNR) and corresponding ADC were also measured. Student t-tests were used for statistical analysis.

Results: Mean SNR values of the normal brain were 33.61±4.35 and 32.98±7.19 for conventional and thin-slice DWI (P>0.05), respectively. Relative signal intensities were significantly higher on thin-section DWI (P<0.05). Mean ADCs of the brain obtained by both techniques were comparable (P>0.05). Quality scores and overall lesion CNR were found to be higher in thin-section DWI with parallel imaging.

Conclusion: A thin-section technique combined with PI improves rSI, CNR, and image quality without compromising SNR and ADC measurements in an acceptable imaging time.

We present diffusion-weighted imaging findings of a case of rhombencephalitis due to Listeria monocytogenes. It is a rare, life-threatening disorder. The diagnosis is difficult by clinical findings only. In this report, we aim to draw attention to the role of conventional and diffusion-weighted magnetic resonance imaging findings. To our knowledge, this is the first case report in the literature with apparent diffusion coefficient values of diseased brain parenchyma.

The association of adrenal pheochromocytoma and brown fat has been described in the pathology literature and scantily in the radiology literature. We present a case of diffuse collection of brown fat in both perinephric spaces associated with left adrenal pheochromocytoma, and describe the computed tomography and magnetic resonance imaging findings.