Part 2: Current Concepts in Radiologic Imaging & Intervention in Acute Biliary Tract Diseases.

Acute cholangitis is encountered commonly in critically ill, often elderly, patients. The most common causes of cholangitis include choledocholithiasis, biliary strictures, and infection from previous endoscopic, percutaneous, or surgical intervention of the biliary tract. Rare causes of acute cholangitis in the United States include sclerosing cholangitis and recurrent pyogenic cholangitis, the latter predominantly occurring in immigrants of Asian descent. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, gastroenterologists, endoscopists, and infectious disease physicians typically involved in the care of these patients. In this paper intended for intensivists predominantly, we will review the imaging findings and radiologic interventional management of critically ill patients with acute cholangitis, primary and secondary sclerosing cholangitis, and recurrent pyogenic cholangitis.

Part 1: Current Concepts in Radiologic Imaging and Intervention in Acute Cholecystitis.

Acute calculous cholecystitis and acute acalculous cholecystitis are encountered commonly among critically ill, often elderly, patients. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, infectious disease physicians, gastroenterologists, and endoscopists able to contribute to patient care. In this article intended predominantly for intensivists, we will review the imaging findings and radiologic treatment of critically ill patients with acute calculous cholecystitis and acute acalculous cholecystitis.

Image-Guided Percutaneous Omental and Mesenteric Biopsy: Assessment of Technical Success Rate and Diagnostic Yield.

PURPOSE: To assess biopsy technique, technical success rate, and diagnostic yield of image-guided percutaneous biopsy of omental and mesenteric lesions. MATERIALS AND METHODS: This retrospective study included 186 patients (89 men, 97 women; mean [SD] age, 63 [13.8] y) who underwent percutaneous image-guided biopsy of omentum and mesentery between March 2007 and August 2015. Biopsies were performed with computed tomography (CT) (n = 172) or ultrasound (US) (n = 14) guidance using coaxial technique yielding core and fine-needle aspiration (FNA) specimens. Biopsy results were classified as diagnostic (neoplastic or nonneoplastic) or nondiagnostic based on histopathology and cytology. Technical success rate and diagnostic yield of omental and mesenteric lesions were calculated. RESULTS: There were 186 image-guided percutaneous biopsies of omental (n = 95) and mesenteric (n = 91) lesions performed. Technical success rate was 99.5% for all biopsies, 100% for omental biopsies, and 98.9% for mesenteric biopsies. Overall sensitivity was 95.5%, specificity was 100%, negative predictive value was 78.3%, and positive predictive value was 100%, which was comparable for omental and mesenteric biopsies. Core biopsies had higher diagnostic yields compared with FNA: 98.4% versus 84% overall, 99% versus 88% for omental biopsies, and 97.7% versus 80% for mesenteric biopsies. Spearman rank correlation showed no correlation between lesion size and diagnostic yield (P = .14) and lesion depth and diagnostic yield (P = .29) for both groups. There were 5 complications. CONCLUSIONS: Image-guided percutaneous omental and mesenteric biopsies have high technical success rates and diagnostic yield regardless of lesion size or depth from the skin for both omental and mesenteric specimens.

Combined endoscopic trangastric drainage and video assisted retroperitoneal pancreatic debridement - The best of both worlds for extensive pancreatic necrosis with enteric fistulae.

Enteric fistula is a serious complication of necrotizing pancreatitis. Endoscopic transluminal drainage and necrosectomy can significantly reduce the incidence of enterocutaneous fistula after pancreatic debridement. However, endoscopic necrosectomy may not be well-suited to debridement of necrosis that tracks laterally to the paracolic gutters, which is often more efficiently addressed by video-assisted retroperitoneal debridement (VARD). We report the combined use of endoscopic transgastric drainage and VARD for treatment of a 76 year old man with severe necrotizing acute pancreatitis complicated by infected, walled-off pancreatic necrosis. Computed tomography showed laterally tracking pancreatic necrosis and flouroscopic drain injection after percutaneous drainage demonstrated with fistulas to the stomach, duodenum, and colon. The infection and fistulas resolved completely. This approach combined the major advantage of VARD with the major advantage of endoscopic transluminal drainage. We are not aware of any reports of combining these techniques and believe the combination offers a minimally invasive approach for patients with extensive necrosis and a high likelihood of enteric or pancreatic fistulas.

Revenue Potential for Inpatient IR Consultation Services: A Financial Model.

PURPOSE: Interventional radiology (IR) has historically failed to fully capture the value of evaluation and management services in the inpatient setting. Understanding financial benefits of a formally incorporated billing discipline may yield meaningful insights for interventional practices. MATERIALS AND METHODS: A revenue modeling tool was created deploying standard financial modeling techniques, including sensitivity and scenario analyses. Sensitivity analysis calculates revenue fluctuation related to dynamic adjustment of discrete variables. In scenario analysis, possible future scenarios as well as revenue potential of different-size clinical practices are modeled. RESULTS: Assuming a hypothetical inpatient IR consultation service with a daily patient census of 35 patients and two new consults per day, the model estimates annual charges of $2.3 million and collected revenue of $390,000. Revenues are most sensitive to provider billing documentation rates and patient volume. A range of realistic scenarios-from cautious to optimistic-results in a range of annual charges of $1.8 million to $2.7 million and a collected revenue range of $241,000 to $601,000. Even a small practice with a daily patient census of 5 and 0.20 new consults per day may expect annual charges of $320,000 and collected revenue of $55,000. CONCLUSIONS: A financial revenue modeling tool is a powerful adjunct in understanding economics of an inpatient IR consultation service. Sensitivity and scenario analyses demonstrate a wide range of revenue potential and uncover levers for financial optimization.

A Quality Improvement Initiative to Reduce Catheter Exchange Rates for Fluoroscopically Guided Gastrostomy Tubes.

PURPOSE: To evaluate the effectiveness of a data-driven quality improvement initiative to reduce catheter exchange rates. MATERIALS AND METHODS: A single-institution retrospective analysis of all percutaneous radiologic gastrostomy (PRG) placement and replacement procedures between January 2010 and July 2015 was conducted. A statistical model predicting the risk for catheter exchange for any reason and exchanges specifically for tube malfunction was created; a quality improvement plan to reduce catheter exchanges was designed and implemented in June 2014. The outcomes for subsequent PRG procedures from July 2014 through March 2015 were followed until July 2015. RESULTS: Between 2010 and June 2014, 1,144 primary PRG procedures and 442 replacement procedures were performed in 1,112 patients. Of the 442 exchange procedures, 289 were "rescue" procedures secondary to catheter malfunction. A quality improvement plan was implemented in June 2014 that encouraged primary gastrojejunostomy catheter and balloon-retained PRG catheter placement and placement of skin sutures in patients considered high risk for catheter dislodgment. From July 2014 through March 2015, 229 PRG catheters were placed, and 71 exchange procedures were performed through July 2015. There was a statistically significant decrease in the number of rescue exchanges performed secondary to catheter malfunction (P = .036). CONCLUSIONS: Procedural and patient-specific risk factors for PRG complications were identified, and a statistical model to predict rates of minor complications was created. These findings were used to implement a quality improvement program that resulted in a decrease in PRG exchanges secondary to catheter malfunction.

Catecholamine Surge during Image-Guided Ablation of Adrenal Gland Metastases: Predictors, Consequences, and Recommendations for Management.

PURPOSE: To identify retrospectively predictors of catecholamine surge during image-guided ablation of metastases to the adrenal gland. MATERIALS AND METHODS: Between 2001 and 2014, 57 patients (39 men, 18 women; mean age, 65 y ± 10; age range, 41-81 y) at two academic medical centers underwent ablation of 64 metastatic adrenal tumors from renal cell carcinoma (n = 27), lung cancer (n = 23), melanoma (n = 4), colorectal cancer (n = 3), and other tumors (n = 7). Tumors measured 0.7-11.3 cm (mean, 4 cm ± 2.5). Modalities included cryoablation (n = 38), radiofrequency (RF) ablation (n = 20), RF ablation with injection of dehydrated ethanol (n = 10), and microwave ablation (n = 4). Fisher exact test, univariate, and multivariate logistical regression analysis was used to evaluate factors predicting hypertensive crisis (HC). RESULTS: HC occurred in 31 sessions (43%). Ventricular tachycardia (n = 1), atrial fibrillation (n = 2), and troponin leak (n = 4) developed during HC episodes. HC was significantly associated with maximum tumor diameter ≤ 4.5 cm (odds ratio [OR], 26.36; 95% confidence interval [CI], 5.26-131.99; P < .0001) and visualization of normal adrenal tissue on CT or MR imaging before the procedure (OR, 8.38; 95% CI, 2.67-25.33; P < .0001). No HC occurred during ablation of metastases in previously irradiated or ablated adrenal glands. CONCLUSIONS: Patients at high risk of catecholamine surge during ablation of non-hormonally active adrenal metastases can be identified by the presence of normal adrenal tissue and tumor diameter ≤ 4.5 cm on pre-procedure CT or MR imaging.

Computed tomography-guided percutaneous biopsy of isoattenuating focal liver lesions.

PURPOSE: The purpose of this study was to evaluate the efficacy of CT-guided percutaneous biopsy of isoattenuating liver lesions using anatomic landmarks (ALs) to guide needle placement and added value of intravenous (IV) contrast. METHODS: An interventional radiology database was reviewed to identify patients with CT-guided percutaneous biopsy of isoattenuating focal liver lesions using ALs to guide needle placement. The cohort was further divided into two groups: lesions biopsied using ALs only and lesions biopsied using ALs and intravenous contrast (AL+IV). Pathology results or follow-up imaging served as reference standard. Sensitivity and accuracy were calculated, Student's t test and Fisher's exact test were used for statistical comparison between the two groups. RESULTS: Between January 2000 and December 2011, CT-guided percutaneous biopsy of 133 isoattenuating focal liver lesions was performed in 133 patients. The AL group included 54 patients (M:F = 29:25) with 54 lesions (size range 7-90 mm, mean 32.1 ± 18.1) and AL+IV group included 79 patients (M:F = 44:35) with 79 lesions (size range 7-100 mm, mean 25.6 ± 15.0). AL group included 23 (43%) benign and 31 (57%) malignant lesions; AL+IV group included 31 (39%) benign and 48 (61%) malignant lesions. Sensitivity and accuracy for CT-guided biopsy of focal isoattenuating liver lesions were, overall 94% and 96%, AL group 97% and 98% and AL+IV group 92% and 94%, with no statistical significant difference between the AL and AL+IV groups (P = 0.88-1.00). CONCLUSION: Accurate planning and utilizing of internal reference ALs is successful in yielding a diagnostic sample for CT-guided percutaneous biopsy of isoattenuating focal liver lesion. The confidence of accurate targeting can be enhanced by administering IV contrast, however, since the visualization provided by IV contrast can be short-lived; use of IV contrast does not obviate the need for precise planning based on ALs.

Transitioning from interventional radiology: ideas for the inevitable.

BACKGROUND: Interventional Radiology (IR) is a highly rewarding specialty, both for its salutary effects for patients, as will as the satisfaction it provides for the operating radiologists. Nonetheless, arduous work and long hours have led to numerous reports of burnout amongst interventional radiologists (IRs). MATERIALS AND METHODS: Six long-term academic radiologists in leadership positions briefly chronicle their becoming IRs, their type of transitioning from IR, and the pros and cons of those respective transitions. RESULTS: The specific transitions include reduced time in IR, switching to diagnostic radiology, becoming involved in medical school education, ceasing IR leadership, and retirement. Pros and cons of the various transition strategies are highlighted. CONCLUSION: As the taxing work and long hours are so ubiquitous for IRs, and as burnout is so common, transitioning from IR is highly likely eventually for IRs. The varied transition experiences highlighted in this report hopefully will be helpful for current and aspiring IRs.

Imaging after percutaneous radiofrequency ablation of hepatic tumors: Part 1, Normal findings.

OBJECTIVE: The purpose of this article is to review the spectrum of early and delayed normal cross-sectional imaging findings after percutaneous radiofrequency ablation of hepatic tumors. CONCLUSION: Knowledge of postablation imaging changes is vital not only for the interventionalist who performs the procedure but also for the diagnostician who interprets the postablation imaging. Recognition of normal postprocedural changes and differentiation from abnormal imaging findings prevent overcalling benign changes as abnormal and can thus avoid needless treatment.

Imaging after percutaneous radiofrequency ablation of hepatic tumors: Part 2, Abnormal findings.

OBJECTIVE: The purpose of this article is to review the spectrum of early and delayed abnormal cross-sectional imaging findings after radiofrequency ablation (RFA) of hepatic tumors. CONCLUSION: Recognition of abnormal post-RFA imaging findings and differentiation of abnormal findings from normal postprocedural changes are important for diagnostic and interventional radiologists. Early identification of residual or recurrent disease and complications can facilitate timely retreatment, management, and follow-up care.

Imaging-guided biopsy of (18)F-FDG-avid extrapulmonary lesions: do lesion location and morphologic features on CT affect the positive predictive value for malignancy?

OBJECTIVE: The purpose of our study was to analyze the effect of lesion location and morphologic appearance on CT on the positive predictive value (PPV) for malignancy of all extrapulmonary lesions that were (18)F-FDG avid on PET/CT and that were biopsied under imaging guidance. MATERIALS AND METHODS: Between January 2004 and December 2010, 227 patients underwent imaging-guided biopsy of 231 PET-positive extrapulmonary lesions with diagnostic pathologic results. The PET PPV for malignancy was retrospectively calculated and stratified according to lesion location and morphologic appearance. RESULTS: The overall PET PPV for malignancy was 72%. Inflammatory processes accounted for the majority of benign biopsy results. Lesion location significantly affected the PPV (p < 0.001). Bone (96%) and liver (90%) lesions had significantly higher PPVs for malignancy compared with other locations, whereas lymph nodes (60%) had a significantly lower PPV for malignancy. Lesions that were morphologically suspicious and morphologically benign according to CT findings alone were associated with PPVs of 74% and 57%, respectively (p = 0.05). FDG-avid subcentimeter lymph nodes (n = 8) had a PPV for malignancy of 38%. CONCLUSION: Over half of PET-avid morphologically benign-appearing lesions and one third of PET-avid subcentimeter lymph nodes were found to be malignant at biopsy, suggesting that benign morphologic appearance alone should not preclude further workup of a PET-positive lesion. Biopsies of FDG-avid lesions in liver and bone yielded high rates of true malignancy, whereas biopsies of lymph nodes yielded a lower rate of malignancy compared with other lesion locations.

The challenging image-guided abdominal mass biopsy: established and emerging techniques 'if you can see it, you can biopsy it'.

Image-guided percutaneous biopsy of abdominal masses is among the most commonly performed procedures in interventional radiology. While most abdominal masses are readily amenable to percutaneous biopsy, some may be technically challenging for a number of reasons. Low lesion conspicuity, small size, overlying or intervening structures, motion, such as that due to respiration, are some of the factors that can influence the ability and ultimately the success of an abdominal biopsy. Various techniques or technologies, such as choice of imaging modality, use of intravenous contrast and anatomic landmarks, patient positioning, organ displacement or trans-organ approach, angling CT gantry, triangulation method, real-time guidance with CT fluoroscopy or ultrasound, sedation or breath-hold, pre-procedural image fusion, electromagnetic tracking, and others, when used singularly or in combination, can overcome these challenges to facilitate needle placement in abdominal masses that otherwise would be considered not amenable to percutaneous biopsy. Familiarity and awareness of these techniques allows the interventional radiologist to expand the use of percutaneous biopsy in clinical practice, and help choose the most appropriate technique for a particular patient.

Mullerian inhibiting substance preferentially inhibits stem/progenitors in human ovarian cancer cell lines compared with chemotherapeutics.

Cancer stem cells are proposed to be tumor-initiating cells capable of tumorigenesis, recurrence, metastasis, and drug resistance, and, like somatic stem cells, are thought to be capable of unlimited self-renewal and, when stimulated, proliferation and differentiation. Here we select cells by expression of a panel of markers to enrich for a population with stem cell-like characteristics. A panel of eight was initially selected from 95 human cell surface antigens as each was shared among human ovarian primary cancers, ovarian cancer cell lines, and normal fimbria. A total of 150 combinations of markers were reduced to a panel of three--CD44, CD24, and Epcam--which selected, in three ovarian cancer cell lines, those cells which best formed colonies. Cells expressing CD44, CD24, and Epcam exhibited stem cell characteristics of shorter tumor-free intervals in vivo after limiting dilution, and enhanced migration in invasion assays in vitro. Also, doxorubicin, cisplatin, and paclitaxel increased this enriched population which, conversely, was significantly inhibited by Müllerian inhibiting substance (MIS) or the MIS mimetic SP600125. These findings demonstrate that flow cytometry can be used to detect a population which shows differential drug sensitivity, and imply that treatment of patients can be individualized to target both stem/progenitor cell enriched and nonenriched subpopulations. The findings also suggest that this population, amenable to isolation by flow cytometry, can be used to screen for novel treatment paradigms, including biologic agents such as MIS, which will improve outcomes for patients with ovarian cancer.

Percutaneous treatment of renal tumours.

Image-guided ablation is an accepted treatment option in the management of renal cell carcinoma. Percutaneous renal ablation offers the possibility of minimally invasive treatment while attempting to preserve renal function. Over the past several years there have been advances in tools and techniques that have improved procedure safety and patient outcomes. This article provides an updated comprehensive review of percutaneous ablation in the management of renal cell carcinoma.

Image-guided biopsy of suspicious lymph nodes in patients with known primary malignancies.

PURPOSE: To determine how often abdominal, pelvic, and inguinal lymphadenopathy in patients with a known malignancy arises from a second primary cancer or from benign causes, rather than from the cancer already known. MATERIALS AND METHODS: A total of 196 patients with a history of a single biopsy-proven malignancy underwent image-guided abdominal or pelvic lymph node (LN) biopsies between January 2000 and January 2005. Three patients were excluded. The medical records and imaging of the remaining 193 patients were reviewed. Pathologic results were assigned to one of three outcomes: LN involvement by known malignancy, newly diagnosed malignancy, or no malignancy identified. Patients in whom malignancy was not identified required repeat biopsy or stability or reduction in size of LN on follow-up imaging for confirmation while not receiving treatment. RESULTS: Of the 193 included biopsies, there was LN involvement by the known malignancy in 148 (76.7%; 95% CI, 70.1%-82.5%), a newly diagnosed malignancy in 19 (9.8%; 95% CI, 6.0%-14.9%), and no malignancy identified in 26 (13.5%; 95% CI, 9.0%-19.1%). CONCLUSIONS: Biopsy of a suspicious abdominal or pelvic LN in patients with known malignancy reveals a newly diagnosed malignancy or no evidence of malignancy in 23% of cases, emphasizing the importance of biopsy.

Image-guided percutaneous splenic interventions.

In the spleen, image-guided interventional procedures such as biopsy and catheter drainage have not been widely performed because of the perceived increased risk of complications. The ability of image-guided biopsy to allow tissue diagnosis of a focal splenic mass without the need for splenectomy is the driving force behind use of this procedure in oncology patients. The literature on image-guided splenic biopsy suggests that the highest biopsy yield is achieved with core biopsy and the lowest complication rate is achieved with fine-needle aspiration. Image-guided catheter drainage is an effective alternative to splenectomy for management of infected splenic collections. In clinical practice, image-guided splenic biopsy, fluid aspiration, and catheter drainage have high success rates. Image-guided alcohol ablation is effective in treatment of splenic cysts. The literature on splenic radiofrequency ablation (RFA) is sparse; therefore, further studies are needed to determine the role of RFA in management of splenic neoplasms and hypersplenism. Image-guided percutaneous thrombin injection can be used to treat splenic artery pseudoaneurysms. Awareness of the correct interventional techniques and their limitations is important for safe performance of image-guided percutaneous splenic interventions.