Portal vein embolization via the ipsilateral percutaneous transhepatic approach versus laparotomic transileocecal approach: complications, profile and changes in future liver remnant volume.

OBJECTIVE: Major liver resection is an effective treatment option for patients with liver malignancy. The future liver remnant (FLR) volume and complications after portal vein embolization (PVE) were compared between the ipsilateral right portal vein (PTPE) and transileocolic (TIPE) approaches. METHODS: A total of 42 patients (TIPE, n = 22; PTPE, n = 20) underwent right lobectomy after PVE. CT and hepatobiliary scintigraphy were repeated before and after PVE. The blood examination findings and the FLR values (FLRCT: calculated from CT, %FLRCT: FLRCT ratio, %FLRSPECT: FLR ratio using single photon emission CT, FLRCT/BS: FLRCT to body surface ratio) were compared between two approach sites. The complications and mortality were also analyzed after PVE and major right hepatectomy. RESULTS: There were no significant differences in the patient characteristics, blood examination findings or FLR values between two groups. Adequate liver regeneration was observed without significant differences between PTPE and TIPE (increased ratio of FLRCT: 8.7% vs 19.2%, p = 0.15 [25-75 percentile: 17.1-60.4], %FLRCT: 11.2% vs 8.3%, p = 0.25 [6.3-13.3], %FLRSPECT: 15.4% vs 19.2%, p = 0.09 [16.0-22.4], FLRCT/BS: 33.6% vs 47.1%, p = 0.19 [17.2-60.4], respectively), but TIPE required a significantly longer procedure time than PTPE [181.4 min vs 108.7 min, p < 0.01 (103.3-193.5)]. However, one patient was converted to TIPE due to bleeding during PTPE. After right lobectomy, portal vein stenosis or thrombosis was noted in three patients [two with TIPE (9.1%) and one with PTPE (5%)] and three TIPE patients died within 90 days (13.6%) after right hepatectomy. CONCLUSION: FLR volume significantly increased after PVE, regardless of the approach sites; however, PTPE is a useful technique with a shorter procedure time.

Assessment of the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase and hepatic signal changes in free-breathing continuous multiphasic dynamic EOB-MRI.

PURPOSE: To investigate the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase (HBP) and the contrast enhancement parameters based on the data of continuous signal changes in free-breathing multiphasic dynamic EOB-MR imaging using a compressed sensing (CS) and the self-gating technique, and to clarify which contrast enhancement parameters are useful for estimating the hepatic enhancement effect in the HPB. METHOD: This study included 96 patients. The contrast enhancement ratio (CER) of the liver parenchyma from phase x to phase y was calculated as follows: CERy-x: (SIy -SIx)/SIx. The gradient of the regression line (GRL) was also calculated. Patients can be divided into two groups with sufficient or insufficient liver enhancement in the HBP, then each parameter was compared between these two groups. RESULTS: In the analysis of the arterioportal phases, CER7-pre in the sufficient HBP enhancement group was significantly higher than that in the insufficient HBP enhancement group (0.50 vs 0.44, p < 0.001). Regarding 5 min early hepatocyte phase (phases 1-28) analysis, significant differences were observed in CER28-pre, CER28-7 and Gradient28-7 between the two groups (0.64 vs 0.47, 0.10 vs 0.03, 1.27 vs 0.27, all p < 0.001). For the strength of correlation, CER7-pre, CER28-pre, CER28-7, and GRL28-7 had higher correlation coefficients, compared with the blood sampling data. CONCLUSION: CER in the arterio-portal phase and 5 min early hepatocyte phase had significant correlation with hepatic contrast enhancement effects in the 20 min HBP, suggesting that sufficient 20 min HBP enhancement may be estimated by the CER in the portal phase and 5 min early hepatocyte phase.

Medical display application for degraded image sharpness restoration based on the modulation transfer function: initial assessment for a five-megapixel mammography display monitor.

An image-display application for medical liquid-crystal display (LCD) monitors called the sharpness recovery (SR) function has been developed to compensate for image sharpness as a function of deficiencies in the modulation transfer function (MTF) of a monitor. We investigated the effects of the SR function for a five-megapixel (MP) mammography LCD monitor on the resolution and noise properties of the displayed images by measuring the MTF and overall noise power spectrum (NPS), respectively. Furthermore, the effectiveness of the SR function for the 5-MP monitor in displaying subtle microcalcifications on digital mammograms was verified using a two-alternative-forced-choice sensitivity measurement as an initial application for medical image interpretation. Four radiologists compared the visibility of 45 regions of interest with a malignant microcalcification cluster shown on SR-processed and unprocessed mammograms. SR processing improved the MTF of the displayed images by approximately 40% at the Nyquist frequency of the 5-MP monitor, whereas it slightly increased the overall NPS values. All observers indicated that the fraction of cases considered to have better visibility of microcalcifications with the SR processing was significantly greater than that without the processing (averaging 82%, with the 95% confidence interval ranging from 70 to 93%). The SR processing for the 5-MP monitor yielded a significant improvement in the resolution properties of the displayed images, with a certain increase in the image noise. The SR function has the potential to improve the observer performance of radiologists, particularly when reading subtle microcalcifications reproduced on 5-MP monitors.

The kinetic analysis of breast cancer: An investigation of the optimal temporal resolution for dynamic contrast-enhanced MR imaging.

INTRODUCTION: There is wide agreement that morphologic features and enhancement kinetics should be evaluated for MRI of the breast, although there has been no clear consensus concerning optimal temporal resolutions. The objective of this study was to investigate the optimal temporal resolution for the kinetic analysis of breast cancers. METHODS: Thirty-four patients with 34 enhancing lesions of breast cancer who underwent dynamic contrast-enhanced MRI (DCE-MRI) on a 3.0-T scanner were included in this retrospective study. DCE-MRI was performed with an original temporal resolution of 10-s, and the values of pharmacokinetic parameters (Ktrans, Ve, Kep, and area under the curve (AUC)) were compared with selected data of 30-s and 60-s time intervals. RESULTS: Among the 34 lesions, 10 showed a wash out pattern, 16 showed a plateau pattern, and 8 showed a persistent enhancement pattern. The Ktrans value in the wash-out pattern was significantly higher than that of other time-intensity curve patterns (p < 0.01). The Kep and AUC also showed significant differences between the wash-out pattern and other types (p < 0.01). On comparing the perfusion parameters among different temporal resolutions, simulations showed that only the AUC differed significantly between the data acquired at a 10-s temporal resolution and that acquired at a 60-s time interval (p < 0.01). Although the comparison of the AUC between the 30-s and 60-s data also showed significant differences (p = 0.01), there was no significant difference between the 10-s and 30-s data (p = 0.17). CONCLUSIONS: DCE-MRI with a temporal resolution of 30-s preserves the kinetic information. Further prospective studies will be needed to investigate the trade-off between temporal and spatial resolution in DCE-MRI.

Influence of fat deposition on T1 mapping of the pancreas: evaluation by dual-flip-angle MR imaging with and without fat suppression.

PURPOSE: To evaluate the influence of fat deposition on T1 relaxation time of pancreatic parenchyma using dual-flip-angle T1 mapping with and without fat suppression. METHODS: Forty-five patients who underwent abdominal MR imaging including T1 mapping with dual-flip-angle method on 3T MRI were included. We measured T1 relaxation time of pancreatic parenchyma on the T1 map images with and without fat suppression. T1 relaxation time of bone marrow was also measured as a reference organ with abundant fat deposition. Fat signal fraction (FSF) was also measured at the same location as T1 map images. Then, the correlation between T1 relaxation time and FSF was assessed. RESULTS: T1 relaxation times of pancreatic parenchyma and bone marrow on the T1 map images without fat suppression showed significantly negative correlation with FSF (pancreas, r = - 0.394, P = 0.007; bone marrow, r = - 0.550, P < 0.001), while there were no significant correlations between them on the T1 map images with fat suppression. On the T1 map images without fat suppression, T1 relaxation times of pancreatic parenchyma as well as bone marrow in patients with FSF ≥ 10% were significantly shorter than those in patients with FSF < 10% (pancreas, P = 0.041; bone marrow, P = 0.005). Conversely, on the T1 map images with fat suppression, no significant differences in T1 relaxation times were found between two groups. CONCLUSION: T1 relaxation time of the pancreas on T1 mapping was influenced by the presence of fat deposition. Therefore, fat suppression technique in T1 mapping will be essential for evaluating T1 relaxation time of pancreatic parenchyma.

Incidentally detected pancreatic adenocarcinomas on computed tomography obtained during the follow-up for other diseases.

PURPOSE: To determine imaging findings of pancreatic adenocarcinomas incidentally detected on contrast-enhanced multiphasic dynamic computed tomography (CT) obtained during the follow-up for other diseases. METHODS: From January 2007 to December 2018, 14 patients with pancreatic adenocarcinomas incidentally detected on CT obtained during the follow-up for other diseases (incidental group) and 105 patients with pancreatic adenocarcinomas symptomatically detected on ultrasound or CT (non-incidental group) were included. Imaging characteristics of the tumor were compared between the two groups. Additionally, imaging findings prior to the detection of a tumor on previous CT images in the incidental group were also assessed. RESULTS: In cancers of the pancreas body/tail, there was a significantly smaller tumor size (median, 17 mm vs. 42 mm, p < 0.001), a significantly lower incidence of loss of fatty marbling (p = 0.025), vascular involvement (p < 0.001), lymph node metastasis (p = 0.046) and distant metastasis (p = 0.017), and a significantly higher incidence of preserved lobulation (p < 0.001) in the incidental group than in the non-incidental group. Regarding the cancers of the pancreas head, there were no significant differences in the radiological findings between the two groups. On previous CT images, small pancreatic nodules, secondary signs, and loss of fatty marbling tended to be the preceding findings of incidental pancreatic adenocarcinomas. CONCLUSION: Incidentally detected pancreatic adenocarcinomas in the pancreas body/tail were characterized by an earlier tumor stage than in cases of symptomatically detected pancreatic adenocarcinoma. Several CT findings prior to the detection of a tumor may be useful for the early detection of pancreatic adenocarcinoma during the follow-up for other diseases.

Liver imaging reporting and data system (LI-RADS) v2018: comparison between computed tomography and gadoxetic acid-enhanced magnetic resonance imaging.

PURPOSE: To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI. MATERIALS AND METHODS: Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images. RESULTS: Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P < 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P < 0.001) CONCLUSION: The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

Histogram-based comparison between dynamic and static lung perfused blood volume images using dual energy CT.

OBJECTIVE: The purpose of this study was to compare the results of a histogram-based analysis of static and dynamic lung perfused blood volume (LPBV) images. METHODS: Sixty-five patients (mean age: 61.3 years, 36 male) underwent dynamic and static LPBV for evaluation of pulmonary vascular diseases (n = 11), lung carcinoma (n = 27) or pulmonary thromboembolism (PTE: n = 27). Seven sets of dynamic sequential scans were performed at the pulmonary trunk using dual-energy technique before the static LPBV scan. The image of lung parenchyma that showed the greatest mean attenuation in dynamic series was defined as the peak dynamic LPBV image. The differences and correlations in the mean attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), histogram skewness and histogram kurtosis were evaluated according to the type of disease in static and dynamic LPBV images. RESULTS: Static LPBV images showed significantly larger mean attenuation (Rt:24.2, Lt: 24.2), SNR (Rt:2.31, Lt:2.30), and CNR (Rt:2.40, Lt:2.39), and smaller kurtosis values (Rt:1.06, Lt:0.61) values in comparison to dynamic LPBV images (p < 0.001); however, with the exception of kurtosis of the left lung (r = 0.17), these values were well-corrected with that of the dynamic LPBV images in these values (r = 0.4-0.77, p ≤ 0.001) without kurtosis of left lung (r = 0.17) in all patients. The histogram kurtosis of static LPBV image showed a good correlation with that of dynamic LPBV (r = 0.41-0.77, p < 0.05), especially in patients with PTE. CONCLUSION: In patients with PTE, the static LPBV image valueswere well correlated with the peak dynamic LPBV images which demonstrated pulmonary artery-dominant flow.

Urinary 8-Hydroxy-2'-Deoxyguanosine as a Myocardial Oxidative Stress Marker Is Associated With Ventricular Tachycardia in Patients With Active Cardiac Sarcoidosis.

BACKGROUND: Recently, we reported that urinary 8-hydroxy-2'-deoxyguanosine (U-8-OHdG), an oxidative stress marker, reflected inflammatory activity in cardiac sarcoidosis (CS). Here, we investigated whether U-8-OHdG levels were associated with ventricular tachycardia (VT) in patients with CS. METHODS AND RESULTS: This prospective cohort study enrolled 62 consecutive patients with CS, of whom 36 were diagnosed as having active CS based on abnormal 18F-flurodeoxyglucose accumulation in the heart on positron-emission tomography/computed tomography. The 36 patients with active CS were subdivided as having CS with sustained VT (CS-VT group; n=18) or CS without sustained VT (CS-nVT group; n=18). Twenty-seven patients diagnosed with idiopathic dilated cardiomyopathy served as heart failure controls. U-8-OHdG, brain natriuretic peptide, cardiac function indices, and immunohistological data from subendomyocardial biopsy samples were compared across groups. Immunohistochemical examination of ventricle biopsy samples revealed that the anti-8-OHdG antibody-positive area of cardiac tissue was significantly greater in CS-VT than in CS-nVT or dilated cardiomyopathy and significantly correlated with U-8-OHdG levels (n=58; R=0.61; P<0.00001), which were significantly higher in CS-VT than in CS-nVT (24.6±7.1 versus 15.2±3.8 ng/mg·Cr; P<0.0001). Other baseline characteristics did not differ between the groups. Multivariate analysis indicated that U-8-OHdG was an independent determinant factor for VT. Receiver operating characteristic curve analysis to identify patients with VT resulted in a U-8-OHdG cutoff value of 17.5 ng/mg·Cr (sensitivity, 89%; specificity, 83%; area under the curve, 0.90). CONCLUSIONS: U-8-OHdG levels are associated with VT in patients with active CS diagnosed by 18F-flurodeoxyglucose positron-emission tomography, providing additive and relevant information about the arrhythmia substrate.

Treatment Options for Celiac Stenosis and Pancreaticoduodenal Artery Aneurysms.

Celiac stenosis may result in a pancreaticoduodenal artery aneurysm (PDAA). Celiac stenosis with a PDAA is rare and treatment guidelines are absent. Here, we report 4 cases of celiac stenosis treated using different methods. Of these, 3 involved PDAAs. The PDAAs were successfully treated with coil embolization. For celiac stenosis, we performed open surgery for decompression in 1 patient, stenting in 2 patients, and bypass grafting in 1 patient. In the patients who underwent stenting, stent-associated thrombosis occurred. PDAAs can be treated with coil embolization; however, treatment of celiac stenosis with the endovascular approach might be difficult.

Intrabullous ventilation in pulmonary emphysema: assessment with dynamic xenon-133 gas SPECT.

PURPOSE: Intrabullous ventilation in patients with pulmonary emphysema (PE) was cross-sectionally evaluated using dynamic xenon-133 gas single photon emission computed tomography (SPECT). METHODS: Fifty-two patients with PE with a total of 109 bullae of more than 4 cm in maximum diameter underwent xenon-133 gas SPECT. The real xenon-133 gas half-clearance time (T1/2) at each bulla was compared with that at the surrounding lung in the same lobe. The emphysema subtype of the surrounding lung was classified into centrilobular, panlobular, and paraseptal on computed tomography (CT). RESULTS: All bullae except for one in all patients showed xenon-133 gas wash-in. Of the 108 bullae with wash-in, 95 (87.9%) bullae in 46 (88%) patients showed marked xenon-133 gas retention with a T1/2 beyond 110 s (mean: 184 s ± 91). The surrounding lungs of these bullae also showed marked retention with a T1/2 of greater than 100 s (mean: 174 s ± 82), and the majority (N=92, 96.8%) were centrilobular or panlobular on CT. The remaining 13 (12.0%) bullae in six (11%) patients showed minimal retention with a T1/2 of less than 80 s (mean: 62 s ± 11), regardless of no significant difference in size compared with the bullae with marked retention. All the surrounding lungs of these bullae except for one also showed minimal retention with a T1/2 of less than 70 s (mean: 60 s ± 18), which was significantly less compared with that of the bullae with marked retention (P<0.0001), and the majority (N=11, 84.6%) were paraseptal with or without an interstitially fibrotic change and predominantly located at the lower lung lobe on CT. The T1/2 of the 108 bullae with xenon-133 gas wash-in was significantly correlated with that of the surrounding lungs (r=0.884, P<0.0001). CONCLUSION: Intrabullous ventilation in patients with PE appears to depend on the ventilation status of the surrounding lung, and bullae with the surrounding lungs of paraseptal-type emphysema tend to show minimal air trapping. Xenon-133 gas SPECT is useful for assessment of the interaction between intrabullous and surrounding lung's ventilation, which is difficult on CT.

Impaired lung 123I-MIBG uptake on SPECT in pulmonary emphysema.

UNLABELLED: The aim of this study was to evaluate impaired lung uptake of (123)I-metaiodobenzylguanidine ((123)I-MIBG) on SPECT, compared with perfusion SPECT and morphologic CT, in patients with pulmonary emphysema (PE). METHODS: (123)I-MIBG SPECT was performed at 15 min and 4 h after intravenous injection of (123)I-MIBG in 36 PE patients with a history of smoking and variable-extent low-attenuation areas on CT, indicative of emphysematous changes, and in 16 controls with no history of smoking and no noticeable low-attenuation areas. The distribution of (123)I-MIBG was compared with that of low-attenuation areas on CT and perfusion on SPECT at the base of the 180 lung lobes of the PE patients. Total-lung (123)I-MIBG kinetics were calculated, including early and delayed lung-to-mediastinum uptake ratios and washout rate. RESULTS: The controls showed a fairly uniform lung (123)I-MIBG distribution nearly consistent with perfusion. PE patients had heterogeneous (123)I-MIBG defects showing frequent discordance with low-attenuation areas or perfusion distribution; (123)I-MIBG defects were more extensive than low-attenuation areas in 76 lobes (42.2%) of 31 patients (86%) and more extensive than perfusion defects in 44 lobes (24.4%) of 22 patients (61%). (123)I-MIBG defects were seen regardless of the absence of noticeable low-attenuation areas and perfusion defects in 19 lobes (10.5%) of 16 patients (44%). All total-lung (123)I-MIBG kinetic parameters in PE patients were significantly lower than the control values (P < 0.0001), with significant correlation with alveolar-arterial oxygen tension gradient but without correlation with the extent of perfusion defects or low-attenuation areas. CONCLUSION: (123)I-MIBG SPECT allows evaluation of lung pathophysiology in PE independently of perfusion SPECT or morphologic CT, and impairment of lung (123)I-MIBG uptake may be more extensive than perfusion or morphologic abnormalities in PE.

Clinical significance of CT density-based, non-uniform photon attenuation correction of deep-inspiratory breath-hold perfusion SPECT.

PURPOSE: The effect of computed tomography (CT) density-based, non-uniform photon attenuation correction (AC) on lung perfusion distribution and the clinical significance were evaluated. MATERIALS AND METHODS: 40 patients with pulmonary emphysema, 32 with pulmonary thromboembolism, 25 with lung cancer and 8 normal controls underwent deep-inspiratory breath-hold (DIBrH) Tc-99m-MAA perfusion SPECT, using a dual-head SPECT system and a respiratory tracking device. Scatter-corrected DIBrH SPECT was automatically co-registered with DIBrH CT. AC of DIBrH SPECT was performed using an attenuation coefficient map of a variable-effective linear coefficient calculated from CT pixel density of the co-registered DIBrH CT. The effect of AC on pulmonary perfusion was evaluated by comparison with uncorrected SPECT. RESULTS: After AC, lung perfusion in normal lungs was increased predominantly at deep lungs near the mediastinum and vertebrae and at the upper-middle lungs, with systematic increases of radioactivity (145 ± 28%) and significant enhancement of physiological gravitational ventral-dorsal gradient (P < 0.01). Throughout the lung diseases, AC significantly enhanced perfusion defect clarity and heterogeneity (P < 0.001), without noticeable artifacts. The correlation between perfusion heterogeneity and the lung diffusing capacity for carbon monoxide was significantly improved in patients with emphysema (P < 0.005). CONCLUSION: CT density-based, non-uniform AC of DIBrH perfusion SPECT provides better assessment of physiologic or impaired perfusion distributions in normal and lung diseases.

Superselective intra-arterial chemotherapy for advanced maxillary sinus cancer: an evaluation of arterial perfusion with computed tomographic arteriography and of tumor response.

OBJECTIVE: The purpose of our study was to elucidate the relationship between arterial perfusion in advanced maxillary sinus cancer which was opacified by superselective intra-arterial computed tomographic arteriography (IA-CTA) and the tumor response to intra-arterial chemotherapy. METHODS: Superselective IA-CTA was performed to identify the feeding arteries and their perfusion in advanced maxillary sinus cancer in 10 patients. Cisplatin was selectively infused into these feeding arteries, except for the internal carotid artery. RESULTS: The results were assessed in 9 of the 10 patients, and a complete response was achieved in 5 patients in whom either the entire tumor, or most of the tumor, was perfused by the branches of the external carotid artery. In 4 patients with a partial response, the residual tumors were seen in the territory of the perfusion defect or in the perfusion territory of the internal carotid artery. CONCLUSION: Superselective IA-CTA is a useful technique to correctly identify the intratumoral perfusion and to predict tumor response to the intra-arterial chemotherapy of advanced maxillary sinus cancer.

Breast sentinel lymph node mapping at CT lymphography with iopamidol: preliminary experience.

PURPOSE: To evaluate sentinel lymph node (SLN) mapping with interstitial computed tomographic (CT) lymphography with small volumes of iopamidol for direction of SLN biopsy in breast cancer. MATERIALS AND METHODS: Thin-section transverse and three-dimensional CT images that included the breast and axilla were acquired at multi-detector row helical CT in 17 patients with operable breast cancer before subcutaneous injection of 2 mL of undiluted iopamidol into peritumoral and periareolar areas and 1-5 minutes after massage of injection sites. Location and size of SLNs were assessed at CT lymphography and were compared with SLNs at standard axillary lymph node dissection with blue dye staining. RESULTS: CT lymphography allowed localization of SLNs in all patients by means of visualization of a direct connection between an SLN and its afferent lymphatic vessels draining from the injection sites. Afferent vessels were joined and drained into a single axillary SLN, except in four patients with two or three SLNs, including a parasternal one. SLNs did not enhance because of rerouting of lymph flow in four patients. At surgery, SLNs that were stained or not stained with blue dye were easily found with CT lymphographic guidance. Tumoral infiltration was not evident in any resected nodes, except for infiltration in one patient with micrometastasis in SLN alone and infiltration in four patients with massive metastasis in both SLN and distant nodes. CONCLUSION: Because preoperative CT lymphography-guided SLN mapping provides SLN position with detailed lymphatic anatomy, it may be useful for the direction of breast SLN biopsy.

Potential of magnetic resonance lymphography with intrapulmonary injection of gadopentetate dimeglumine for visualization of the pulmonary lymphatic basin in dogs: preliminary results.

PURPOSE: To evaluate a new approach of magnetic resonance (MR) lymphography with intraalveolar injection of a conventional extracellular contrast agent (gadopentetate dimeglumine) for imaging lymphatic basin draining from specific portions of the lung. METHODS: Three-dimensional T1-weighted spoiled gradient-recalled echo MR sequence images were acquired serially before and for 40 minutes after intraalveolar injection of gadopentetate dimeglumine in a total of 14 anesthetized beagle dogs. Six of these dogs received 1 mL undiluted and low-concentration (75%) contrast agent into the same portion of the right caudal lobe during a 7-day interval. In all dogs, including these 6 dogs, MR lymphography was repeated with injection of the low-concentration contrast agent into different lung regions at 7-day intervals to evaluate the differences of the visualized draining lymphatic station. Lymphatic enhancement was quantified by percent increases of signal intensity against precontrast. Postmortem examination of the lymphatic anatomy was performed in 7 of these animals. RESULTS: In all dogs, the lymphatic station draining from the injection sites was visualized within 5 minutes after contrast injection. The maximum percent increase of signal intensity of the same middle tracheobronchial lymph nodes was significantly greater with a low-concentration (75%) contrast agent than with an undiluted one in the same 6 dogs (n = 6, 247.6 +/- 30.5% vs. 204.2 +/- 33.8%; P < 0.01). Different lymphatic stations draining from the different injection sites were visualized in all dogs. In a total of 12 MR studies that showed extended nodal enhancement after injection of the low-concentration contrast agent, the enhancement peak of the most proximal nodes (n = 12) from the injection sites appeared earlier than that of their distant nodes (n = 12), with a maximum percent increase of signal intensity of 249.8 +/- 42.4%. The visualized lymph nodes were found in the appropriate locations postmortem, with significant correlation for nodal sizes (r = 0.965; P < 0.0001). CONCLUSION: MR lymphography with low-concentration gadopentetate dimeglumine can quickly and sufficiently visualize the drainage lymphatic station from specific lung portions, and may have the potential of sentinel node mapping in lung cancer.

Interstitial CT lymphography-guided localization of breast sentinel lymph node: preliminary results.

BACKGROUND: Accurate localization of the breast sentinel lymph node (SLN) can be challenging as a minimally invasive approach to the treatment of early-stage breast cancer. We tested the potential capability of interstitial computed tomographic lymphography (CT-LG) using a conventional contrast agent (iopamidol) for SLN mapping. METHODS: In 14 female dogs, 0.5 and 1 mL of undiluted iopamidol was injected subcutaneously into the 2 skin areas overlying the mammary gland. Contiguous, 2 mm-thick multidetector helical CT images were obtained through the upper breast and axilla before, and for 60 minutes after, gentle massage at the injection site. Three-dimensional (3D) CT images were obtained from the postcontrast images showing the greatest SLN enhancement. This CT-LG with 2 mL of iopamidol was also evaluated in 5 human female volunteers. RESULTS: The direct connection of SLN and lymphatic vessels draining from the injection sites in the animal models was clearly visualized, even with 0.5 mL of iopamidol. With this dose, the SLN attenuation was maximally enhanced, with a mean of 274 Hounsfield units (HU) on the first postcontrast images. The topographic 3D images provided the comprehensive anatomy of these lymphatic pathways. Of the 28 SLNs and 184 distant nodes visualized on CT images, all of the SLNs (100%) and 161 (87.5%) of the distant nodes could be resected at premortem and/or postmortem, with a good correlation in the locations and sizes with those on the CT images. The CT-LG effectively localized 5 SLNs with averaged maximum attenuation of 223 HU in the human volunteers, without any significant adverse effects. CONCLUSION: Interstitial CT-LG using small volumes of iopamidol can sufficiently visualize breast lymphatic drainage and may have potential utility for breast SLN mapping.