Radiofrequency (RF) ablation is becoming an accepted treatment modality for many tumors of the liver and is being explored for tumors in the lung, kidney, and bone. While RF energy is the most familiar heat source for tissue ablation, it has certain limitations that may hamper its efficacy in these new organ systems. Microwave energy may be a better source for tissue ablation but has technical hurdles that must be overcome as well. This article outlines the physics behind RF and microwave heating, discusses relevant properties of the liver, lung, kidney, and bone for thermal ablation and examines the roles of RF and microwave ablation in these tissues.
Interventional radiology-operated endoscopy is an underused technique, which may have a significant impact on the ability to treat patients with a variety of conditions. The purpose of this article is to discuss the setup, equipment, and potential clinical uses of interventional radiology-operated endoscopy. A number of new and innovative interventions may be performed in the biliary, genitourinary, and gastrointestinal systems through percutaneous access that interventional radiologists already create. When used in combination, endoscopy adds an entirely new dimension to the fluoroscopic-guided procedures of which interventional radiologists are accustomed. Interventional radiologists are in a unique position to implement endoscopy into routine practice given the manual dexterity and hand-eye coordination already required to perform other image-guided interventions. Although other specialists traditionally have performed endoscopic interventions and local politics often dictate referral patterns, a collaborative relationship among these specialists and interventional radiology will allow for improved patient care. A concerted effort is needed by interventional radiologists to learn the techniques and equipment required to successfully incorporate endoscopy into practice.
Response Evaluation Criteria in Solid Tumors (RECIST), including version 1.0 and 1.1, has been universally accepted as the standard response assessment criteria for conventional chemotherapies. Increasing use of immunotherapy led to the need and development of immune-related RECIST. Imaging plays a crucial role in response assessment for solid tumors in guiding patient management as well as in clinical trials. Familiarity to different response criteria will help radiologists to optimally identify, select, and measure tumor lesions per the criteria and assess response to therapy. This article provides a comprehensive review of published RECIST criteria.
Adrenal tumors are very commonly encountered in the practice of radiology. They may arise from the adrenal gland itself, either the cortex or the medulla, or they could be secondary lesions. They may be benign or malignant. The functioning adrenal tumors lead to hypersecretion of adrenal hormones leading to clinical syndromes. Computed tomography is the most common imaging modality used for the initial evaluation of adrenal tumors. Magnetic resonance imaging and functional scintigraphic techniques are frequently used for atypical presentations or further evaluation. We present a multimodality review of common and uncommon adrenal tumors. We highlight their characteristic and specific imaging features which help us in making a diagnosis and suggesting an appropriate follow up for further management. The spectrum of adrenal tumors is wide with varying appearances on different imaging modalities. Imaging techniques used for adrenal tumor imaging have their own strengths and weaknesses as it relates to the final diagnosis. It is important to be familiar with imaging characteristics of adrenal tumors for appropriate diagnosis and management. Differentiation of benign (leave alone) tumors from malignant (surgical) ones along with appropriate disposition of incidentalomas are some of the challenges facing the radiologist.
Hepatic small vessel hemangioma represents a distinct yet very rare pathologic entity of the liver. The entity has also been in the past referred to as adult capillary hemangioma of the liver and congenital noninvoluting hemangioma. Imaging findings are not definitive and biopsy or resection is ultimately necessary. Pathologically these represent vasoformative abnormalities with infiltrative margins that can potentially mimic hepatic angiosarcoma. Immunohistochemistry can help differentiate hepatic small vessel hemangioma from angiosarcoma. Given the infiltrative growth pattern and unknown outcomes, resection and or close follow up has been recommended. Recently the term hepatic small vessel neoplasm has been coined in view of the unknown outcomes and some concerning findings on molecular analysis. We report 2 cases of this unusual entity and describe its imaging, gross pathologic, histopathologic, and immunohistochemical features.
To evaluate the utility of a defecography phase (DP) sequence in dynamic pelvic floor MRI (DPMRI), in comparison to DPMRI utilizing only non-defecography Valsalva maneuvers (VM). Inclusion criteria identified 237 female patients with symptoms and/or physical exam findings of pelvic floor prolapse. All DPMRI exams were obtained following insertion of ultrasound gel into the rectum and vagina. Steady-state free-precession sequences in sagittal plane were acquired in the resting state, followed by dynamic cine acquisitions during VM and DP. In all phases, two experienced radiologists performed blinded review using the H-line, M-line, Organ prolapse (HMO) system. The presence of a rectocele, enterocele and inferior descent of the anorectal junction, bladder base, and vaginal vault were recorded in all patients using the pubococcygeal line as a fixed landmark. DPMRI with DP detected significantly more number of patients than VM (p<0.0001) with vaginal prolapse (231/237, 97.5% vs. 177/237, 74.7%), anorectal prolapse (227/237, 95.8% vs. 197/237, 83.1%), cystocele (197/237, 83.1% vs. 108/237, 45.6%), and rectocele (154/237, 65% vs. 93/237, 39.2%). The median cycstocele (3.2cm vs. 1cm), vaginal prolapse (3cm vs. 1.5cm), anorectal prolapse (5.4cm vs. 4.2cm), H-line (8cm vs. 7.2cm) and M-line (5.3cm vs. 3.9cm) were significantly higher with DP than VM (p<0.0001). Addition of DP to DPMRI demonstrates a greater degree of pelvic floor instability as compared to imaging performed during VM alone. Pelvic floor structures may show mild descent or appear normal during VM, with marked prolapse on subsequent DP images.
To promote opportunities for medical students to gain early exposure to radiology and research, our institution has initiated programs which fund summer radiology research projects for rising second-year medical students. This study assesses the impact of these faculty-mentored summer research experiences on medical student perceptions of radiology and research, in terms of both knowledge and interest. A voluntary, anonymous survey was administered to students both before and after the summer research period. Both the pre-program survey and post-program survey included 7-point Likert-scale questions (1 = strongly disagree; 7 = strongly agree) to evaluate students’ perceptions about research and students’ perceptions about radiology as a specialty. Faculty mentors were sent an analogous post-program survey that included an evaluation of their student's research skills. The surveys were completed by 9 of 11 students and 10 of 11 mentors. Students’ perceived knowledge of radiology as a specialty improved ( = 0.02) between the pre-program survey and post-program survey. Similarly, there was an increase in students’ perceived knowledge of research skills ( = 0.02) between the pre-program survey and post-program survey, with student ratings of research skills consistent with those of mentors. High student interest in both radiology and research was maintained over the course of the program. Our pilot study suggests that summer research experiences can improve knowledge of radiology and research among medical students. Continued evaluation of this annual program will allow us to enhance the benefit to medical students and thereby bolster interest in academic radiology.
Preparing residents for the on-call experience in Radiology is one of the most important aspects of education within a training program. Traditionally, this preparation has occurred via a combination of case conferences and didactic lectures by program faculty, daily teaching at the workstation, and precall assessments. Recently, a blended curricular model referred to as the flipped classroom has generated a lot of attention within the realm of graduate medical education. We applied this technique to resident precall education in the subspecialty of Neuroradiology, and surveyed the participants about their perceptions of the course. The structure, implementation, and web-based platform used to create the flipped classroom experience is described herein.
The purpose of this study was to describe and compare the management recommendations provided in the setting of a high-risk lesion diagnosed on core needle biopsy of the breast at academic institutions across the United States. We contacted breast imagers at U.S. academic institutions via email and asked them to complete a voluntary online survey. The survey consisted of eight questions regarding the management recommendations given when core biopsy yields various high-risk lesions. We received survey responses from 41 of the 59 institutions contacted (69% response rate). Surgical excision was the most frequently reported recommendation given for all high-risk lesions; however, the proportion varied from 95% for atypical ductal hyperplasia and papilloma with associated atypia, 76% for flat epithelial atypia, 73% for radial scar/complex sclerosing lesion, 71% for lobular carcinoma in-situ, 61% for atypical lobular hyperplasia, to 39% for intraductal papilloma without atypia. Our study demonstrates inconsistency in the management recommendations given for high-risk lesions detected on core needle biopsy at academic institutions nationally. This outcome suggests that patients may benefit from the creation of consensus recommendations for the management of high-risk lesions detected on core needle biopsy.
Recognizing and preventing diagnostic errors is an increasingly emphasized topic across medicine, and abdominal imaging is no exception. Peer-learning strives for quality improvement through understanding why errors occur and identifying opportunities to prevent errors from recurring. In an effort to learn from mistakes, our abdominal imaging section initiated a Peer Learning Conference, where errors are discussed and compartmentalized into oneor more of the following categories: Observation, Interpretation, Communication, and Inadequate Data Gathering. In this manuscript, the structure of our Peer Learning Conference is introduced and the components of each discrepancy category are described in detail. Images are included to highlight learning points through exemplary cases from the conference.
A broad spectrum of pathology affects the rectum, anus, and perineum, and multiple imaging modalities are complementary to physical examination for assessment and treatment planning. In this pictorial essay, correlative imaging, endoscopic, pathologic, and operative images are presented for a range of rectal, perirectal, and perineal disease processes, including infectious/inflammatory, traumatic, congenital/developmental, vascular, and miscellaneous conditions. Key anatomic and surgical concepts are discussed, including radiological information pertinent for surgical planning, and current operative approaches of these anatomic spaces to assist radiologists in comprehensive reporting for gastroenterologists and surgeons.
To use a natural language processing and machine learning algorithm to evaluate inter-radiologist report variation and compare variation between radiologists using highly structured versus more free text reporting. 28,615 radiology reports were analyzed for 4 metrics: verbosity, observational terms only, unwarranted negative findings, and repeated language in different sections. Radiology reports for two imaging examinations were analyzed and compared – one which was more templated (ultrasound – appendicitis) and one which relied on more free text (chest radiograph – single view). For each metric, the mean and standard deviation for defined outlier results for all dictations (individual and group mean) was calculated. The mean number of outlier metrics per reader per study was calculated and compared between radiologists and between the two report types. Wilcoxon rank test and paired Wilcoxon signed rank test were applied. The radiologists were also ranked based on the number of outlier metrics identified per study. There was great variability in radiologist dictation styles – outlier metrics per report varied greatly between radiologists with the maximum 10 times higher than the minimum score. Metric values were greater (P < 0.0001) on the standardized reports using free text than the more structured reports. The algorithm successfully evaluated metrics showing variability in reporting profiles particularly when there is free text. This variability can be an obstacle to providing effective communication and reliability of care.
Disorders of the kidney and urinary collecting system are common encountered in the acute care setting. Computed tomography has progressively replaced intravenous pyelography for the evaluation of most urinary tract pathology including acute flank pain, suspected malignancy, congenital abnormalities, anatomical variants, and inflammatory/vascular conditions through evaluation of the “nephrogram” produced by intravenous contrast material filtering through the kidneys. In this review, we describe the most common types of abnormal nephrograms seen on renal computed tomography, and highlight the salient features and conditions associated with them, in addition to a pictorial review with specific and interesting related cases. The types of abnormal nephrograms reviewed are absent, unilateral delayed, striated, spotted, and persistent.
Breast Conserving Therapy (BCS) or lumpectomy has been an established treatment option for women with early-stage invasive breast cancers. Surgical margin status has a significant impact on local recurrence. However, there is much complexity in achieving a negative lumpectomy margin. There are multiple risks and predictors of positive surgical margins that the radiologist needs to be familiar with. When working as a member of a multidisciplinary team, it is important to be cognizant of the pathologist's and surgeon's roles in reducing the number of failed breast conserving surgeries. Despite the common use of imaging to help avoid positive surgical margins, it is important to remember the limitations of standard intraoperative specimen radiographs. A negative resection margin is the goal of BCS ensuring decrease of local recurrence, increased cosmesis, and improved long-term survival.
Interval breast cancers are those detected in the interim between regular screening examinations and are an unfortunate reality for breast cancer screening programs. However, their incidence can help gauge the success of breast cancer screening programs. There are four main categories of interval cancers, including true negative, false negative, minimal sign, and occult. The mammographic characteristics of each type of interval cancer are reviewed with example cases from an urban academic institution. Pitfalls and strategies to reduce interval cancers are discussed in detail.
A large number of chest radiography studies in our department include extra images due to incompletely imaged anatomy (eg, extra frontal view to include a truncated costophrenic angle). Negative impacts include: increased radiologist review time due to disruption of search pattern and the need to review additional films in slightly different obliquities, additional radiation exposure, and increased technologist time expenditure. To determine the chest radiograph repeat rate, collaborate with technologists on a process to decrease the frequency, and incorporate the process into our quality control program. Data collection was performed by using coded dictation macros to indicate the type of extra view (frontal, lateral) and whether the extra image was necessary due to patient habitus. Twelve weeks after the macro was instituted, baseline data were collected by querying the macro codes with a search engine (MONTAGE Search and Analytics). Intervention consisted of in-person tutorials of basic radiographic positioning principles with x-ray technologists and posting of checklists in all diagnostic radiology exam rooms. Twelve weeks of postintervention data were collected. Baseline data included 5645 examinations, of which 335 (5.9%) included extra images. Postintervention, 5943 examinations were performed and 295 (5.0%) included extra images. A significant decrease in the frontal view repeat rate was noted, decreasing from 4.6%-3.3% ( = 0.001). The repeat rate of lateral images did not change significantly (3.1%-3.2%). Data monitoring and interprofessional collaboration led to a significant decrease in unnecessary extra radiographs. Ongoing monitoring may lead to sustained improvement and further reductions.
To differentiate intra-axial tuberculomas (TB) from metastases based on quantitative differences in the perfusion and diffusion indices of lesion and perilesional edema using arterial spin labeling (ASL) and diffusion tensor imaging (DTI) techniques. This prospective study included newly diagnosed untreated 12 patients of TB and 13 of metastases who underwent routine magnetic resonance imaging including DTI and ASL sequences. A region of interest analysis was performed and cerebral blood flow (CBF) values of lesion (L), perilesional edema (PE), and normal contralateral white matter (CWM) were calculated. To account for individual patient variation CBF values were normalized (n) to CWM to obtain the nCBFL and nCBFPE ratios. Similarly, DTI data was processed to obtain fractional anisotropy (FA), mean diffusivity, radial diffusivity, and axial diffusivity values from the lesion and PE. Metastatic lesions revealed statistically significant (p = 0.001) high values of median nCBFL than TB whereas the difference in the median nCBFPE was not statistically significant (p = 0.174). TB showed higher median FAL compared to metastases (p = 0.031) while no statistically significant difference was found in mean values of other diffusion parameters such as mean diffusivity, radial diffusivity and axial diffusivity. Analysis by the receiver operating characteristic curve method revealed a cut-off value of ≥2.865 for nCBFL (Sensitivity = 0.85, Specificity = 0.84, positive predictive value (PPV) = 0.85, Negative predictive value (NPV) = 0.83) and ≤0.073 for FAL (Sensitivity = 0.77, Specificity = 0.58, PPV = 0.67, NPV = 0.70) in differentiating metastases from TB. Combined analysis of noncontrast ASL perfusion and DTI technique may markedly benefit in differentiation of TB from metastases.
Fractures of the thoracolumbar spine account for up to 90% of spinal fractures, and are associated with significant disability. The advantage of acquiring dedicated spine CT imaging in addition to visceral CT studies of the chest, abdomen and pelvis for detection of spinal fractures has not been definitively established. This retrospective study seeks to determine the contribution of dedicated spine CT in the acute clinical setting. Patients who were diagnosed with fractures of the thoracic or lumbar spine at our institution between January 1, 2010 and June 30, 2014 were identified. Additional inclusion criteria included having a CT of the chest and/or abdomen and pelvis followed by a dedicated thoracic or lumbar spine CT within 30 days. Reports were reviewed for accuracy of fracture detection, and missed fractures were retrospectively analyzed on images for detectability. A total of 102 patients met our inclusion criteria for a total of 312 fractures. Of the 312 fractures, 31 (10%) were missed on the initial visceral CT in 18 of the 102 patients. In all but two cases, at least one fracture was identified on the visceral spine CT. There were no cases in which the newly identified fractures changed patient management. All fractures requiring surgical intervention were identified on the visceral CT. A dedicated spine CT does detect additional spine fractures but does not clearly alter patient management.