The Incidental Splenic Mass at CT: Does It Need Further Work-up? An Observational Study.

Purpose To evaluate whether an incidentally noted splenic mass at abdominal computed tomography (CT) requires further imaging work-up. Materials and Methods In this institutional review board-approved HIPAA-compliant retrospective study, a search of a CT database was performed for patients with splenic masses at CT examinations of the abdomen and chest from 2002 to 2008. Patients were divided into three groups: group 1, patients with a history of malignancy; group 2, patients with symptoms such as weight loss, fever, or pain related to the left upper quadrant and epigastrium; and group 3, patients with incidental findings. Patients' CT scans, follow-up examinations, and electronic medical records were reviewed. Final diagnoses of the causes of the masses were confirmed with imaging follow-up (83.9%), clinical follow-up (13.7%), and pathologic examination (2.4%). Results This study included 379 patients, 214 (56.5%) women and 165 (43.5%) men, with a mean age ± standard deviation of 59.3 years ± 15.3 (range, 21-97 years). There were 145 (38.3%) patients in the malignancy group, 29 (7.6%) patients in the symptomatic group, and 205 (54.1%) patients in the incidental group. The incidence of malignant splenic masses was 49 of 145 (33.8%) in the malignancy group, eight of 29 (27.6%) in the symptomatic group, and two of 205 (1.0%) in the incidental group (P < .0001). The incidental group consisted of new diagnoses of lymphoma in one (50%) patient and metastases from ovarian carcinoma in one (50%) patient. Malignant splenic masses in the incidental group were not indeterminate, because synchronous tumors in other organs were diagnostic of malignancy. Conclusion In an incidental splenic mass, the likelihood of malignancy is very low (1.0%). Therefore, follow-up of incidental splenic masses may not be indicated. © RSNA, 2018.

Thirty-day emergency room visits and hospital admissions after outpatient non-vascular image-guided procedures.

PURPOSE: To evaluate the rate of post-procedure emergency department (ED) visits and hospital admissions following outpatient non-vascular image-guided interventions performed under moderate sedation and to identify common and preventable causes of emergency department visits and hospital admissions. MATERIALS AND METHODS: Institutional review board approval was acquired for this HIPAA-compliant retrospective study with waiver of informed consent. 1426 consecutive patients undergoing 1512 outpatient image-guided procedures under moderate sedation from November 2012 to August 2014 were included. The average patient age was 57.2 ± 15.2 years, and 602 (42%) patients were women. Major procedure categories included ultrasound-guided liver biopsies, ultrasound-guided kidney biopsies, and CT-guided lung biopsies/fiducial placement. Procedure details and medical follow-up within and after 30 days of the procedure were analyzed. RESULTS: A total of 168 (11.8%) patients were admitted to the hospital within 30 days of the procedure, with 29 of the admissions (17.3% of total admissions and 1.9% of total procedures) being procedure related. The most common procedure-related complication that required admission was hemorrhage (10/29, 34.5% of procedure-related admissions, 6.0% of total admissions, and 0.7% of total procedures), followed by pneumothorax (9/29, 31%, 5.4%, 0.6%), infection (4/29, 13.8%, 2.4%, 0.3%), and pain (3/29, 10.3%, 1.8%, 0.2%). Eighteen (62.1%) procedure-related admissions were immediately indicated. Thirty patients visited the ED and were subsequently discharged without admission with eight of the visits being procedure related (8/1512, 0.5%). All the procedure-related ED visits were due to pain. There were two deaths (2/1512, 0.1%) related to procedures, one from a thromboembolic event and another from post-biopsy hemorrhage. CONCLUSION: Outpatient non-vascular image-guided procedures result in a 30-day 1.9% hospital admission, 30-day 0.5% emergency room visit, and 30-day 0.1% mortality rate.

Diagnostic yield and clinical impact of microbiologic diagnosis from CT-guided drainage in patients previously treated with empiric antibiotics.

PURPOSE: The purpose of the study was to evaluate diagnostic yield and the added value of culture results on the clinical management of patients empirically treated with antibiotics prior to CT-guided drainage. METHODS: This retrospective, HIPAA-compliant, IRB-approved study reviewed records of 300 consecutive patients who underwent CT-guided aspiration or drainage for suspected infected fluid collection while on empiric antibiotics (11/2011 to 9/2013) at a single institution. Patient imaging and clinical characteristics were evaluated by an abdominal imaging fellow and culture results, and patient management were evaluated by an infectious diseases fellow. RESULTS: After exclusion of 14/300 (4.6%) patients who were not on empiric antibiotics and 8/300 (2.6%) patients in which no culture was acquired, 278 patients (average age 55 ± 16 years; M:F ratio 54:46) constituted the final study cohort. Leukocytosis was present in 163/278 (59%), and fever in 65/278 (24%). The average collection size was 8.5 ± 4.2 cm with gas present in 140/278 (50%) of collections; median amount drained was 35 mL, and visibly purulent material was obtained in 172/278 (63%). 236/278 (85%) received drains and the remainder were aspirated only. Average time between initiation of antibiotics and start of the drainage procedure was 4.1 ± 6.4 days (median 1.7 days). Cultures were positive in 205/278 (74%) patients with a resulting change in management in 181/278 (65%) cases. The change in management included change of antibiotics in 71/278 (26%), narrowing the antibiotic regimen in 94/278 (34%), and cessation of antibiotics in 16/278 (6%). Multidrug-resistant bacteria were cultured in 53/278 (19%). Several factors were found to be statistically significant predictors of positive cultures: patient leukocytosis (sens 62%, spec 53%), gas in the collection on CT (sens 59%, spec 77%), purulent material aspiration (sens 76%, spec 76%), and presence of polymorphonuclear cells in the specimen. CONCLUSIONS: Despite predrainage antibiotic therapy, CT-guided drainage demonstrates a high yield of positive cultures and influences clinical management in the majority of patients.

CT Imaging Findings after Stereotactic Radiotherapy for Liver Tumors.

Purpose. To study radiological response to stereotactic radiotherapy for focal liver tumors. Materials and Methods. In this IRB-approved, HIPAA-compliant study CTs of 68 consecutive patients who underwent stereotactic radiotherapy for liver tumors between 01/2006 and 01/2010 were retrospectively reviewed. Two independent reviewers evaluated lesion volume and enhancement pattern of the lesion and of juxtaposed liver parenchyma. Results. 36 subjects with hepatocellular carcinoma (HCC), 25 with liver metastases, and seven with cholangiocarcinoma (CCC) were included in study. Mean follow-up time was 5.6 ± 7.1 months for HCC, 6.4 ± 5.1 months for metastases, and 10.1 ± 4.8 months for the CCC. Complete response was seen in 4/36 (11.1%) HCCs and 1/25 (4%) metastases. Partial response (>30% decrease in long diameter) was seen in 25/36 (69%) HCCs, 14/25 (58%) metastases, and 7/7 (100%) of CCCs. Partial response followed by local recurrence (>20% increase in long diameter from nadir) occurred in 2/36 (6%) HCCs and 4/25 (17%) metastases. Liver parenchyma adjacent to the lesion demonstrated a prominent halo of delayed enhancement in 27/36 (78%) of HCCs, 19/21 (91%) of metastases, and 7/7 (100%) of CCCs. Conclusion. Sustainable radiological partial response to stereotactic radiotherapy is most frequent outcome seen in liver lesions. Prominent halo of delayed enhancement of the adjacent liver is frequent finding.

Cytologic rapid on-site evaluation of transthoracic computed tomography-guided lung needle biopsies: who should perform ROSE? A cross-institutional analysis of procedural and diagnostic outcomes.

INTRODUCTION: Cytologic rapid on-site evaluation (ROSE) during minimally invasive biopsy procedures is an increasingly important service provided by cytopathology to increase diagnostic yield and appropriately triage cellular material. Although ROSE can be performed by cytopathologists, cytotechnologists, or cytopathology fellows, few studies have directly compared both procedural and diagnostic outcome measures among different ROSE personnel. MATERIALS AND METHODS: We evaluated all transthoracic computed tomography (CT)-guided lung biopsies in which ROSE was performed during a 1-year period at 2 academic institutions with similar patient populations and procedural methods: Dartmouth-Hitchcock Medical Center (DHMC) (where ROSE is performed by cytopathologists) and the Beth Israel Deaconess Medical Center (BIDMC) (where ROSE is rendered by either cytotechnologists or cytopathology fellows). RESULTS: A total of 273 CT-guided transthoracic lung biopsies (190 DHMC, 83 BIDMC) were analyzed. There was no major difference in procedure time with respect to ROSE personnel. The repeat procedure rate for nondiagnostic biopsies was similar at DHMC (cytopathologists) and BIDMC (cytotechnologists or cytology fellows) (2.1% versus 2.3%, P = 1.0). Adequacy rates for cytopathologists, cytotechnologists, and cytopathology fellows were comparable (P = 0.23). ROSE assessments by cytopathologists were more concordant with the final diagnosis (87%) than those by cytotechnologists (82%) or cytopathology fellows (79%); this difference was not statistically significant (P = 0.28). CONCLUSIONS: ROSE procedural and diagnostic outcomes for transthoracic CT-guided lung biopsies were similar among cytopathologists, cytotechnologists, and cytopathology fellows.

Calcium score: semiautomatic calculation using different vendors versus fully automatic software.

OBJECTIVES: Recent advances in technology have resulted in a multitude of cardiac imaging postprocessing software products from vendors unrelated to the scanner on which the cardiac study was initially performed. A fully automatic calcium score software has also become available. We assess the intervendor variability of calcium score measurement using the semiautomatic software provided by the scanner vendor versus an unrelated vendor versus fully automatic software. METHODS: All consecutive patients who had a calcium score performed from March 2007 to January 2008 were included in this study. The studies were performed on two 64-slice computed tomographic scanners from 2 different vendors. The allocation of the patient to the specific scanner was done according to scanner and technologist availability. The studies were read twice by a cardiac radiologist and a general radiologist with at least 3 months' interval at a workstation specified by the computed tomographic scanner vendor and then at an unrelated workstation, with semiautomatic software. Calcium score was also independently performed by the fully automatic software, blinded to the results of previous readings. Agreement was tested with Pearson correlation coefficient, Bland-Altman graphs, and the Fleiss κ test. RESULTS: The study population included 101 patients: 70 patients scanned at 1 scanner and 31 at a different scanner. Intervendor variability for the 2 groups had κ = 0.98 ± 0.01 and κ = 0.96 ± 0.02; interobserver variability had κ = 1. Semiautomatic versus automatic variability showed κ = 0.88 to 0.94. CONCLUSIONS: Because of very strong agreement between the calcium score measurements obtained by semiautomatic and fully automatic software by different vendors, calcium score measurements can be performed robustly at vendor-specific software, nonrelated software, or fully automatic software.

CT-guided core biopsy and percutaneous fiducial seed placement in the lung: can these procedures be combined without an increase in complication rate or decrease in technical success?

OBJECTIVE: To determine if concomitant CT-guided biopsy and percutaneous fiducial seed placement in the lung can be performed in a selective patient population without increased complication or decreased success rates compared to either procedure alone. MATERIALS AND METHODS: An IRB approved retrospective analysis of 285 consecutive patients that underwent CT-guided placement of fiducial seeds in the lung alone (N=63), with concomitant core biopsy (N=53) or only core biopsy (N=169) was performed. Variables compared included: patient demographics, lesion size, depth from pleura, needle size, number of passes through pleura, number and size of core biopsies, number of seeds placed and technical success rates. Statistical analysis was performed using univariate and multivariate pair-wise comparisons. RESULTS: A pathologic diagnosis of malignancy was confirmed in all cases undergoing seed placement alone and seed placement with concurrent biopsy, and in 144 of the biopsy alone lesions. On univariate analysis, major complication rates were similar for all three groups as were lesion size, depth, number of pleural passes, and technical success. Pair-wise comparisons of the remaining variables demonstrated a significant younger age and smaller needle size in the biopsy only group, and less minor complications in the fiducial only group. Overall there were 80/285 (28.1%) minor and 29/285 (10.2%) major complications. All major complications leading to admission consisted of either pneumothorax or hemothorax, while minor complications included asymptomatic stable or resolving pneumothoraces, transient hemoptysis or small hemothoraces. CONCLUSIONS: A combined procedure of percutaneous pulmonary core biopsy and stereotactic seed placement can be performed without additional risk of a major complication when compared to performing these separately.

Pancreatic atrophy in patients with chronic graft-versus-host disease.

PURPOSE: To determine if patients with chronic graft-versus-host disease (cGVHD) following allogeneic hematopoietic stem cell transplantation (HSCT) develop greater loss of pancreatic tissue than patients without cGVHD. MATERIALS AND METHODS: This is an IRB-approved, HIPAA-compliant retrospective study of patients receiving allogeneic HSCT at our institution from 01/2006 to 01/2010 with abdominal CT performed within 3 months prior to HSCT and CT performed at least 3 months after HSCT. Measurement of glandular tissue thickness of the head, body, and tail of the pancreas was performed independently by two radiologists blinded to clinical data. Statistical analysis was performed using the Student t-test, and interobserver agreement was evaluated with linear-weighted kappa. RESULTS: 117 patients underwent HSCT during study period, with 36 patients meeting inclusion criteria. 22 subjects (61%) had clinical features of cGVHD, and 14 patients (39%) did not have evidence of cGVHD. Following HSCT, there was a significant decrease in mean total thickness (10.9%, p = 0.002) of the pancreas in the group of patients with cGVHD. The change from pretreatment to the nadir in pancreatic thickness was significantly greater in patient with cGVHD (13.9 ± 12.1 mm), but not in non-cGVHD patients (5.4 ± 4.7 mm) (p = 0.02), with head of the pancreas atrophy accounting for the difference (decrease of 4.8 ± 4.6 mm in cGVHD patients vs. 1.6 ± 2.1 mm in non-cGVHD patients (p = 0.02)). CONCLUSION: Patients with cGVHD develop significantly greater loss of pancreatic glandular tissue than patients without cGVHD following HSCT, with atrophy of pancreatic head being a major contributor.

Diagnostic radiology of transjugular intrahepatic portosystemic shunts.

Transjugular intrahepatic portosystemic shunts (TIPS) are an effective method for treating the complications of portal hypertension. Specific indications for TIPS include secondary prevention of variceal bleeding and refractory ascites. The purpose of this review is to summarize the role of diagnostic radiology in the creation and assessment of TIPS, to highlight the complications that can occur post-TIPS, and to critically evaluate the literature regarding ultrasound evaluation of TIPS.

Critically compromised airway secondary to expanding esophageal mucocele.

Expanding mucocele is a known but rare complication of bypass and surgical exclusion of the thoracic esophagus. When functional esophageal mucosa secretes mucin into the blind esophageal loop, tissue expansion can cause mass effect on nearby structures. We report the case of a critically compromised airway secondary to a dilated esophageal mucocele initially managed with right thoracotomy, partial esophagectomy and mucosectomy. This was complicated by mucocele recurrence, which was successfully managed with computed tomography-guided drainage and absolute alcohol ablation of residual mucosa.

In vivo determination of a modified heat capacity of small hepatocellular carcinomas prior to radiofrequency ablation: correlation with adjacent vasculature and tumour recurrence.

PURPOSE: To calculate a modified heat capacity (mHC) of small hepatocellular carcinomas (HCCs) in vivo during radio frequency ablation (RFA) and to determine if mHC correlates with tumour vascularity, adjacent vessels or local recurrence. PATIENTS AND METHODS: This study was IRB approved and informed consent was obtained from all patients. Before formal RFA, ambient HCC temperature and temperature 1 min after heating at constant wattage were measured in 29 patients. From temperature change and wattage, individual mHCs (joules required to increase tumour temperature by 1° Celsius) were calculated. Pre-RFA, three-phase computerised tomography (CT) scans were reviewed blindly for hepatic arteries, hepatic veins and portal veins abutting or within 3 mm of tumour edge from which twelve vascular parameters were quantified. Tumour enhancement (homogeneous or heterogeneous on arterial phase) was also assessed. Multiple regression was used to correlate mHC with vascular parameters and tumour enhancement. Cox proportional hazard model was used to examine the relationship of mHC to local recurrence. RESULTS: There was significant correlation of mHC with lesion enhancement (P = 0.0018), length of hepatic arteries (P < 0.0001) and total hepatic vein volume in contact with tumour (P = 0.016). No correlation was found with any non-abutting vessel or portal vein parameter. The chance of local recurrence increased with increasing mHC. CONCLUSION: Because the modified heat capacity of small HCCs in our study population correlated with HCC enhancement, abutting hepatic arteries, the volume of abutting hepatic veins and local recurrence, it may be an indicator of the heat sink effect (HSE) and supports the HSE as a risk factor for local recurrence.

Incidentally detected misty mesentery on CT: risk of malignancy correlates with mesenteric lymph node size.

OBJECTIVE: To determine the natural history of incidentally detected misty mesentery on computed tomography (CT) and to correlate the risk of malignancy with size of mesenteric lymph nodes. METHODS: A retrospective review of all CT abdomen/pelvic examinations from January 1, 2004 through December 31, 2008 identified cases of misty mesentery. The largest mesenteric lymph node was measured, and additional areas of lymphadenopathy were identified. Follow-up was obtained by reviewing all subsequent CT examinations, clinical notes, and pathologic specimens. Patients were excluded if they had a known malignancy at the time of initial CT, CT or clinical history revealing a cause for the misty mesentery, or CT follow-up of less than 2 years. RESULTS: Thirty-seven patients with misty mesentery were included. The mean time from the original CT to the latest follow-up was 3.8 years. The largest lymph node measured less than 10 mm in 30 (81%) of 37 patients. All 30 patients demonstrated stable lymph node size, had no other regions with lymphadenopathy, and none developed malignancy. The largest lymph node was 10 mm or greater in 7 (19%) of 31 patients. Three of these patients developed non-Hodgkin lymphoma, 2 of which had other areas of lymphadenopathy. No cases of nonlymphomatous malignancy were identified. CONCLUSIONS: The development of malignancy in patients with incidentally detected misty mesentery correlates with mesenteric lymph node size. Patients with misty mesentery and largest mesenteric lymph node less than 10 mm without additional areas of lymphadenopathy demonstrate a benign course, and no further follow-up may be necessary.

Safety profile and technical success of imaging-guided percutaneous fiducial seed placement with and without core biopsy in the abdomen and pelvis.

OBJECTIVE: The purpose of this study is to determine whether complications associated with combining biopsy and percutaneous fiducial seed placement in the abdomen and pelvis exceeds that of either procedure alone or prohibits completion of the combined procedure. MATERIALS AND METHODS: A retrospective review was performed of 188 consecutive patients who underwent CT- or ultrasound-guided placement of fiducial seeds in the abdomen or pelvis, either alone (group 1, n = 117) or with concomitant biopsy (group 2, n = 71), from October 2005 through April 2010. Complications classified according to the Society of Interventional Radiology guidelines were compared between both groups using the Z test for proportions, as were the number of seeds per patient and seed migration and technical success rates. RESULTS: One hundred eighty-eight patients underwent percutaneous placement of 533 fiducial seeds in the abdomen and pelvis. Eight patients (4.3%) had complications. Five were minor (four small hematomas and one pneumothorax) and three were major (two cases of bleeding and one of sepsis). There was no significant difference between groups with respect to minor complication rates, number of seeds placed per patient (p = 0.85), or technical success (p = 0.33). Significantly more major complications (p = 0.04) occurred in group 2, but the rate was similar to that for percutaneous biopsy alone as reported in the literature. Group 2 also had more seed migration (p = 0.02). CONCLUSION: Biopsy and fiducial seed placement in the abdomen and pelvis can be performed in the same session rather than separately, with a high rate of technical success and without an increased risk of complications when compared with either procedure alone.

Incidentally detected gallbladder polyps: is follow-up necessary?--Long-term clinical and US analysis of 346 patients.

PURPOSE: To determine the natural history of gallbladder (GB) polyps incidentally detected at ultrasonography (US) and to propose management guidelines for these lesions based on polyp size. MATERIALS AND METHODS: The HIPAA-compliant study was approved by the institutional review board, and informed consent was waived. A database search for "polyp" in all US examinations of the GB between January 1, 1999, and December 31, 2001, at a single institution was performed. All subsequent US reports were reviewed to determine changes in GB polyp size. The electronic medical record was searched to obtain clinical and pathologic follow-up. RESULTS: Three hundred forty-six patients (mean age, 51.6 years; range, 20-93 years) with GB polyps were included. There were 156 men (45%) and 190 women (55%). US follow-up (mean, 5.4 years; range, 2-11.5 years) was performed in 149 patients (43%). Polyp size was stable in 90 (60%) polyps, decreased in eight (5%), increased in one (1%), and resolved in 50 (34%). Forty-two patients (12%) underwent cholecystectomy, revealing 13 (31%) GBs with polypoid lesions, 24 (57%) with stones and no polyps, and five (12%) with neither a stone nor a polypoid lesion. Clinical follow-up (mean, 8 years; range, 5-10.4 years) was performed in 155 patients (45%). No patient had clinical evidence of GB-related disease. Overall, no cases of GB malignancy were identified in 346 patients. Mean polyp size was 5.0 mm (range, 1-18 mm). No neoplastic polyps were found at 1-6 mm, one neoplastic polyp was seen at 7-9 mm, and two neoplastic polyps were found at 10 mm or larger. CONCLUSION: The risk of GB malignancy resulting from incidentally detected polyps is extremely low. Incidentally detected GB polyps measuring 6 mm or less may require no additional follow-up. Data are inconclusive regarding polyps 7 mm or greater, and further studies are warranted.

Efficacy of radiofrequency ablation in the treatment of small functional adrenal neoplasms.

PURPOSE: To evaluate the use of radiofrequency (RF) ablation as a primary treatment for symptomatic primary functional adrenal neoplasms and determine the efficacy of treatment with use of clinical and biochemical follow-up. MATERIALS AND METHODS: After obtaining institutional review board approval, the authors retrospectively evaluated images and medical records from 13 consecutive patients with symptomatic functional adrenal neoplasms (<3.2 cm in diameter) who underwent RF ablation during a 7-year period. There were six men and seven women with a mean age of 54.1 years (range, 42-71 years). Cross-sectional images, findings from clinical examination, and adrenal biochemical markers were available for all patients. Ten of the 13 patients (77%) had an aldosteronoma and one patient each had a cortisol-secreting tumor, testosterone-secreting tumor, and pheochromocytoma. RF ablation was performed by two radiologists using an internally cooled electrode and a pulsed technique according to manufacturer's specifications. Clinical and laboratory follow-up was performed for all patients. Three patients underwent imaging follow-up for other reasons. RESULTS: All patients demonstrated resolution of abnormal biochemical markers after ablation (mean biochemical follow-up, 21.2 months). In addition, all patients experienced resolution of clinical symptoms or syndromes, including hypertension and hypokalemia (in patients with aldosteronoma), Cushing syndrome (in the patient with cortisol-secreting tumor), virilizing symptoms (in the patient with testosterone-secreting tumor), and hypertension (in the patient with pheochromocytoma). For the patients with aldosteronoma, improvements in hypertension management were noted. The mean blood pressure before ablation was 149/90 mm Hg with a mean (±standard deviation) of 3.1 ± 0.6 blood pressure medications, and this decreased to 122/77 mm Hg at a mean of 2.8 months after ablation with 1.3 ± 0.9 medications (P < .001) and 124/75 mm Hg at a mean of 41.4 months. There were two minor complications: one small pneumothorax and one limited hemothorax, neither of which required overnight admission. There were two episodes of transient self-remitting procedural hypertension-one in a patient with aldosteronoma and one in the patient with a cortisol-secreting tumor; however, none of these patients required further therapy during overnight observation. CONCLUSION: RF ablation may be an effective, minimally invasive method for treating small functional primary adrenal tumors.

Can Doppler sonography discern between hemodynamically significant and insignificant portal vein stenosis after adult liver transplantation?

OBJECTIVE: The purpose of our study was to determine whether Doppler sonography, using a strict reference standard, can specifically identify hemodynamically significant portal vein anastomotic stenosis after liver transplantation in adults. MATERIALS AND METHODS: The duplex and color Doppler examinations of 13 consecutive adult patients who underwent portal venography for suspected portal vein stenosis after liver transplantation were retrospectively examined. Peak systolic velocity (PSV) and change in PSV (ΔPSV) along the portal vein were correlated with portal venography. Stenoses above 50% on the basis of strict venographic criteria were considered hemodynamically significant. The Doppler studies before and after intervention were also assessed. Fourteen randomly chosen subjects with transplants without suspicion of portal anastomotic stenosis acted as controls. RESULTS: Six patients had significant portal vein stenosis (> 50%) and seven had stenosis below 50%. PSV and ΔPSV were significantly greater for patients with > 50% stenosis in comparison with those with ≤ 50% stenosis and control subjects. Optimal threshold values for PSV and ΔPSV were 80 and 60 cm/s, respectively, with either value alone yielding sensitivity of 100% and specificity of 84% for significant stenosis. Threshold values also included cases of stenosis below 50%. Five of six patients with > 50% stenosis underwent stenting, with poststent PSV and ΔPSV significantly declining to match that of control subjects. Three of seven with stenosis below 50% had stents placed but no significant change in the Doppler examination. CONCLUSION: Doppler threshold criteria reliably exclude those without posttransplantation portal vein stenosis and have high sensitivity for detecting portal stenosis. However, these criteria cannot discern the extent of stenosis.

Quality initiatives: strategies for anticipating and reducing complications and treatment failures in hepatic radiofrequency ablation.

Radiofrequency (RF) ablation is one of several local treatment strategies that can be used for the destruction of a variety of primary and secondary liver tumors. As experience with RF ablation grows, it becomes increasingly evident that successful ablation requires meticulous technique. In addition, knowledge of potential complications is critical for both the interventionalist and the radiologist, whose postablation interpretation can facilitate identification of complications and treatment failures. Hepatic RF ablation offers significant advantages in that it is less invasive than surgery and carries a low risk of major complications. Successful prevention of complications and treatment failures begins at initial consultation and continues with preablation evaluation of specific patient factors such as coagulation profiles, use of medications, and risk factors for infection. Other predisposing factors include background liver cirrhosis, prior hepatectomy, and portal hypertension. During ablation, careful attention must be given to tumor size, number, and location. For large or multiple ablations, separate ablation sessions can help reduce the prevalence of postablation syndrome, and clustered electrodes and multiple overlapping treatment zones may be used to reduce the risk of treatment failure. It is critical to reevaluate tumors during ablation to determine the best approach and to compensate for changes in size and relative location due to patient positioning. With use of these strategies, hepatic RF ablation can be performed with greater safety, better patient tolerance, and a reduced risk of complications and treatment failures.

Feasibility of measurement of pancreatic perfusion parameters with single-compartment kinetic model applied to dynamic contrast-enhanced CT images.

PURPOSE: To examine the feasibility of measuring pancreatic perfusion parameters by using a single-compartment kinetic model applied to contrast material-enhanced computed tomographic (CT) images. MATERIALS AND METHODS: This study received institutional review board approval and was HIPAA compliant. Informed consent was waived. Eight subjects (four men, four women; median age, 40 years; range, 35-57 years), all potential renal donors with no pancreatic pathologic abnormalities, underwent abdominal CT imaging, which resulted in 30 10-mm-thick sections obtained at a single level. Imaging was a direct result of bolus timing employed for standard renal donor protocol; no additional imaging beyond what was clinically warranted was performed. Images were obtained every 3 seconds; scanning was initiated at the onset of contrast material administration. Region-of-interest measurements were obtained for the pancreatic body and the aorta to generate time-enhancement curves (TECs). A one-compartment model was applied by using the aortic and pancreatic TECs as the input and output functions, respectively. Pancreatic volumetric blood flow F(V), volume of distribution V(D), and blood transit time tau were determined. Modeled pancreatic TECs were generated and were compared with actual TECs for wellness of fit. RESULTS: Pancreatic F(V) values from the single-compartment model ranged from 0.961 to 6.405 min(-1) (mean, 3.560 min(-1) +/- 1.900 [standard deviation]). Volume of distribution V(D) ranged from 1.491 to 3.080 (mean, 2.383 +/- 0.638), while values of tau ranged from -3.090 to 6.436 seconds (mean, 0.481 second +/- 3.000). Modeled pancreatic TECs closely matched true pancreatic TECs for each subject, with R(2) values ranging from 0.840 to 0.959. CONCLUSION: A simple one-compartment kinetic model can be applied to contrast-enhanced images of normal pancreas to yield accurate pancreatic TECs, which attest to the perfusion parameters obtained. In addition to yielding volumetric blood flow similar to that of other models of tissue perfusion, two additional pancreatic perfusion parameters can be obtained. SUPPLEMENTAL MATERIAL: http://radiology.rsnajnls.org/cgi/content/full/2492080026/DC1.