Clinician overconfidence in visual estimation of the posthepatectomy liver remnant volume: A proximal source of liver failure after major hepatic resection?

BACKGROUND: Post-hepatectomy liver failure is a source of morbidity and mortality after major hepatectomy and is related to the volume of the future liver remnant. The accuracy of a clinician's ability to visually estimate the future liver remnant without formal computed tomography liver volumetry is unknown. METHODS: Twenty physicians in diagnostic radiology, interventional radiology, and hepatopancreatobiliary surgery reviewed 20 computed tomography scans of patients without underlying liver pathology who were not scheduled for liver resection. We evaluated clinician accuracy to estimate the future liver remnant for 3 hypothetical major hepatic resections: left hepatectomy, right hepatectomy, and right trisectionectomy. The percent-difference between the mean and actual computed tomography liver volumetry (mean percent difference) was tested along with specialty differences using mixed-effects regression analysis. RESULTS: The actual future liver remnant (computed tomography liver volumetry) remaining after a hypothetical left hepatectomy ranged from 59% to 75% (physician estimated range: 50%-85%), 23% to 40% right hepatectomy (15%-50%), and 13% to 29% right trisectionectomy (8%-39%). For right hepatectomy, the mean future liver remnant was overestimated by 95% of clinicians with a mean percent difference of 22% (6%-45%; P < .001). For right trisectionectomy, 90% overestimated the future liver remnant by a mean percent difference of 25% (6%-50%; P < .001). Hepatopancreatobiliary surgeons overestimated the future liver remnant for proposed right hepatectomy and right trisectionectomy by a mean percent difference of 25% and 34%, respectively. Based on years of experience, providers with <10 years of experience had a greater mean percent difference than providers with 10+ years of experience for hypothetical major hepatic resections, but was only significantly higher for left hepatectomy (9% vs 6%, P = .002). CONCLUSION: A clinician's ability to visually estimate the future liver remnant volume is inaccurate when compared to computed tomography liver volumetry. Clinicians tend to overestimate the future liver remnant volume, especially in patients with a small future liver remnant where the risk of posthepatectomy liver failure is greatest.

Imaging of the hepatic arterial infusion pump: Primer for radiologists.

Hepatic arterial infusion (HAI) pumps are used to deliver liver-directed therapy by allowing the administration of selective chemotherapy to the liver via a catheter implanted most commonly into the gastroduodenal artery connected to a subcutaneous pump. This selective administration helps maximize the chemotherapeutic effect within the hepatic tumors while minimizing systemic toxicity. While HAI therapy has primarily been used to treat liver-only metastatic colorectal cancer, the indications have expanded to other malignancies, including intrahepatic cholangiocarcinoma. Radiologists play an important role in pre-operative planning, assessment of treatment response, and evaluation for potential complications using various imaging studies, including computed tomography angiography, magnetic resonance imaging, and perfusion scintigraphy. This article describes the radiologist's role as part of a multi-disciplinary oncology team to help maximize the success of HAI therapy and also helps radiologists familiarize themselves with various aspects of HAI pumps.

ACR Appropriateness Criteria® Left Lower Quadrant Pain: 2023 Update.

The differential diagnosis for left lower quadrant pain is wide and conditions range from the benign and self-limited to life-threatening surgical emergencies. Along with patient history, physical examination, and laboratory tests, imaging is often critical to limit the differential diagnosis and identify life-threatening abnormalities. This document will discuss the guidelines for the appropriate use of imaging in the initial workup for patients who present with left lower quadrant pain, patients with suspected diverticulitis, and patients with suspected complications from diverticulitis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Rectal cancer lexicon 2023 revised and updated consensus statement from the Society of Abdominal Radiology Colorectal and Anal Cancer Disease-Focused Panel.

The Society of Abdominal Radiology's Colorectal and Anal Cancer Disease-Focused Panel (DFP) first published a rectal cancer lexicon paper in 2019. Since that time, the DFP has published revised initial staging and restaging reporting templates, and a new SAR user guide to accompany the rectal MRI synoptic report (primary staging). This lexicon update summarizes interval developments, while conforming to the original lexicon 2019 format. Emphasis is placed on primary staging, treatment response, anatomic terminology, nodal staging, and the utility of specific sequences in the MRI protocol. A discussion of primary tumor staging reviews updates on tumor morphology and its clinical significance, T1 and T3 subclassifications and their clinical implications, T4a and T4b imaging findings/definitions, terminology updates on the use of MRF over CRM, and the conundrum of the external sphincter. A parallel section on treatment response reviews the clinical significance of near-complete response and introduces the lexicon of "regrowth" versus "recurrence". A review of relevant anatomy incorporates updated definitions and expert consensus of anatomic landmarks, including the NCCN's new definition of rectal upper margin and sigmoid take-off. A detailed review of nodal staging is also included, with attention to tumor location relative to the dentate line and locoregional lymph node designation, a new suggested size threshold for lateral lymph nodes and their indications for use, and imaging criteria used to differentiate tumor deposits from lymph nodes. Finally, new treatment terminologies such as organ preservation, TNT, TAMIS and watch-and-wait management are introduced. This 2023 version aims to serve as a concise set of up-to-date recommendations for radiologists, and discusses terminology, classification systems, MRI and clinical staging, and the evolving concepts in diagnosis and treatment of rectal cancer.

Update on The National Accreditation Program for Rectal Cancer (NAPRC): the radiologist's role.

The National Accreditation Program for Rectal Cancer (NAPRC) was established by the American College of Surgeons with the goal of standardizing care of rectal cancer patients in order to improve outcomes. NAPRC accreditation requires compliance with an established set of standards, many of which are directly related to radiology participation in multidisciplinary conference, rectal MR image acquisition, interpretation and reporting, and radiologist education. This paper outlines the pertinent standards/requirements for radiologists as part of the Rectal Cancer Multidisciplinary Team in the NAPRC guidelines, with proposed methods and tips for implementation of these standards from the perspective of the radiologist.

ACR Appropriateness Criteria® Hernia.

Abdominopelvic hernias are common clinical entities composed of a wide variety of congenital, traumatic, and iatrogenic etiologies. Any weakness in the body wall may result in hernia of cavity contents with concomitant risks of morbidity and mortality. Presentations may be specific, palpable body wall mass/bulge, or vague, nonspecific pain through bowel obstruction. This document focuses on initial imaging of the adult population with signs of symptoms prompting suspicion of abdominopelvic hernia. Imaging of the abdomen and pelvis to evaluate defects is essential for prompt diagnosis and treatment. Often CT and ultrasound are the first-line modalities to quickly evaluate the abdomen and pelvis, providing for accurate diagnoses and management of patients. MRI protocols may be useful as first-line imaging studies, especially in patients with orthopedic instrumentation. Although often performed, abdominal radiographs and fluorographic procedures may provide indirect evidence of hernias but are usually not indicated for initial diagnosis of hernia. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update.

This document focuses on imaging in the adult and pregnant populations with right lower quadrant (RLQ) abdominal pain, including patients with fever and leukocytosis. Appendicitis remains the most common surgical pathology responsible for RLQ abdominal pain in the United States. Other causes of RLQ pain include right colonic diverticulitis, ureteral stone, and infectious enterocolitis. Appropriate imaging in the diagnosis of appendicitis has resulted in decreased negative appendectomy rate from as high as 25% to approximately 1% to 3%. Contrast-enhanced CT remains the primary and most appropriate imaging modality to evaluate this patient population. MRI is approaching CT in sensitivity and specificity as this technology becomes more widely available and utilization increases. Unenhanced MRI and ultrasound remain the diagnostic procedures of choice in the pregnant patient. MRI and ultrasound continue to perform best in the hands of the experts. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Staging of Colorectal Cancer: 2021 Update.

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Hepatic arterial infusion pump chemotherapy combined with systemic therapy for patients with advanced colorectal liver metastases: Outcomes in a newly established program.

BACKGROUND AND OBJECTIVES: Colorectal liver metastasis (CRLM) is a leading cause of morbidity and mortality in patients with colorectal cancer. Hepatic arterial infusion (HAI) chemotherapy has been demonstrated to improve survival in patients with resected CRLM and to facilitate conversion of technically unresectable disease. METHODS: Between 2016 and 2018, n = 22 HAI pumps were placed for CRLM. All patients received systemic chemotherapy concurrently with HAI floxuridine/dexamethasone. Overall survival (OS) and progression-free survival (PFS) were assessed using the Kaplan-Meier method. RESULTS: HAI pumps were placed in seven patients with completely resected CRLM and 15 patients with unresectable disease. Twenty-one patients received HAI floxuridine with a median of 5 total HAI cycles (interquartile range: 4-7). Biliary sclerosis was the most common HAI-related complication (n = 5, 24%). Of the 13 patients treated to convert unresectable CRLM, 3 (23%) underwent hepatic resection with curative intent after a median of 7 HAI cycles (range: 4-10). For all HAI patients, the mean OS was 26.7 months from CRLM diagnosis, while the median PFS and hepatic PFS from pump placement were 9 and 13 months, respectively. CONCLUSION: Concomitant HAI and systemic therapy can be utilized at multidisciplinary programs for patients with advanced CRLM, both in the adjuvant setting and to facilitate conversion of unresectable disease.

ACR Appropriateness Criteria® Anorectal Disease.

This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Conventional hepatic arterial anatomy? Novel findings and insights of a multi-disciplinary hepatic arterial infusion pump program.

INTRODUCTION: Variant hepatic arterial anatomy (vHAA) is thought to occur in 20-30% of patients. Hepatic arterial infusion (HAI) pump placement for liver cancers requires thorough hepatic artery dissection; we sought to compare vHAA identified during pump placement with established dogma. METHODS: Between 2016 and 2020, n = 30 patients received a HAI pump. Intra-operatively identified vHAA was characterized and compared with published data. RESULTS: vHAA was identified in 60% (n = 18) of patients, significantly higher than 19% (3671 of 19013) in the largest published series (P < 0.001). The most common variations were accessory left (n = 12; 40%) and replaced right (n = 6; 20%) hepatic arteries; six (20%) had ≥2 variants. Pre-operative imaging correctly identified 67% of variant hepatic arteries. DISCUSSION: Meticulous operative dissection of the hepatic arterial tree reveals vHAA not captured by imaging or cadaveric dissection. vHAA likely has a higher prevalence than previously reported and should be addressed to optimize therapeutic efficacy of HAI pump therapy.

MRI of prostatic urethral mucinous urothelial carcinoma: Expanding the differential diagnosis for T2 hyperintense prostatic masses.

We report the case of a 66-year-old previously healthy man presenting with blood and mucus in his urine. Cystoscopy revealed a mass in the prostatic urethra, and endoscopic biopsy showed adenocarcinoma in situ with mucinous features. Endorectal multiparametric prostate MRI demonstrated a 1.9 cm T2 hyperintense mass in the peripheral zone of the left prostatic apex with extension into the urethral lumen. No diffusion restriction or early enhancement was seen in the mass. Radical prostatectomy was performed, and final pathology demonstrated a mucin-producing urothelial adenocarcinoma arising from the prostatic urethra. The peripheral zone T2 hyperintense abnormality correlated with abundant pools of mucin extending into the prostatic stroma and surrounded by neoplastic prostatic glandular cells. We conclude prostatic urethral mucinous urothelial carcinoma should be included in the differential diagnosis for T2 hyperintense prostatic masses.

Case series of collapsed simple renal cysts potentially simulating cystic malignancy at CT.

The radiological differential diagnosis for complex renal cysts seen at CT generally includes cystic malignancy or renal abscess. We have encountered five cases of complex-appearing renal cysts at CT where serial imaging and clinical outcome favored a diagnosis of a collapsed benign simple renal cyst. We present these cases to broaden the differential diagnosis for complex renal cysts seen at CT, highlighting the importance of careful correlation with prior imaging to assist in correct recognition of collapsed simple cysts and potentially allowing for conservative management or surveillance.

Radiological appearances of corpus luteum cysts and their imaging mimics.

PURPOSE: To review the radiological appearances of corpus luteum cysts and their imaging mimics. CONCLUSION: Corpus luteum cysts are normal post-ovulatory structures seen in the ovaries through the second half of the menstrual cycle and the first trimester of pregnancy. The typical appearance, across all modalities, is of a 1- to 3-cm cyst with a thick crenulated vascularized wall. Occasionally, similar imaging findings may be seen with endometrioma, ectopic pregnancy, tuboovarian abscess, red degeneration of a fibroid, and ovarian neoplasia. In most cases, imaging findings are distinctive and allow for a confident and accurate diagnosis that provides reassurance for patients and referring physicians and avoids costly unnecessary follow-up.

Prostate cancer with a pseudocapsule at MR imaging: a marker of high grade and stage disease?

Clinicopathological correlates of prostate cancer associated with a pseudocapsule at T2-weighted magnetic resonance (MR) imaging are presented in a retrospective series of 15 patients. Of 15 tumors, 14 involved the peripheral zone. Extracapsular extension was seen in 14 cases. Tumor Gleason score was 8 or above in 12 of 15 cases, and ductal type adenocarcinoma was identified in 4 cases. Step section histopathological correlation (n=5) demonstrated that the pseudocapsule corresponded with dense compressive or reactive peritumoral fibrosis. A pseudocapsule around prostate cancer at T2-weighted MR imaging is a rare finding that appears to be associated with high grade and stage disease.

Direct MRI-guided biopsy of the prostate: use of post-biopsy needle track imaging to confirm targeting.

PURPOSE: To report the observation that in-plane post-biopsy T2-weighted MRI often demonstrates the needle track as a transient visible linear tissue distortion during direct MRI-guided biopsy. MATERIALS AND METHODS: We retrospectively identified 11 prostatic lesions in 9 men that underwent direct MRI-guided biopsy and in which post-biopsy images were obtained in the plane of the biopsy needle. RESULTS: In 9 of 11 targets, a post-biopsy needle track was visible as a linear tissue distortion on in-plane T2-weighted images obtained at a mean interval of 6 min (range 3-15). In these nine cases, the needle track traversed the intended target, and the biopsy was positive for malignancy in six. Biopsy was positive in one of two cases where the needle track was not visible. In five targets, one or more delayed series were obtained after a mean interval of 21 min (range 8-33), showing the track was no longer visible (n = 3) or was of progressively decreased conspicuity (n = 2). CONCLUSION: Accurate targeting during direct MRI-guided biopsy of the prostate can be confirmed by obtaining post-biopsy in-plane images, since the needle track is usually visible as a transient linear tissue distortion.

Imaging of invasive thymoma in the costophrenic recess presenting as thickening of arcuate ligaments of the diaphragm.

Imaging findings in a patient with invasive thymoma in the costophrenic recess are presented, in whom computed tomography (CT) and MRI revealed lateral arcuate ligament thickening. Increased fluoro-deoxy-glucose (FDG) uptake on subsequent positron emission tomography (PET)/CT was helpful in suggesting the correct diagnosis. A second patient with much more obvious invasive thymoma occurring in the costophrenic recess is presented for comparison. It is a well-known fact that thymic malignancies can metastasize to the pleura even years after resection. Rarely, they may present as focal thickening of the diaphragmatic lateral arcuate ligament.