Courtney C. Moreno

Variability of MDCT dose due to technologist performance: impact of posteroanterior versus anteroposterior localizer image and table height with use of automated tube current modulation.

OBJECTIVE The purpose of this study was to determine MDCT dose variability due to technologist variability in performing CT studies. MATERIALS AND METHODS Fifty consecutive adult patients who underwent two portal venous phase CT examinations of the abdomen and pelvis on the same 64-MDCT scanner between January and December 2011 were retrospectively identified. Tube voltage (kVp), tube current (mA), use of automated tube current modulation (ATCM), dose-length product (DLP), volume CT dose index (CTDIvol), table height, whether the localizer image was obtained using the posteroanterior or the anteroposterior technique, arm position, and number of overscanned slices were recorded. RESULTS For a given patient, the total examination DLP difference comparing the two MDCT studies ranged from 0.1% to 238.0%. For the same patient, total examination DLP was always higher when the localizer image was obtained with the posteroanterior compared with the anteroposterior technique. When table position was closer to the x-ray source, patients appeared magnified in the posteroanterior localizer image (8-29%; average, 14%) and higher tube currents were selected with ATCM. Localizer technique, table height, arm position, number of overscanned slices, and technologist were all significant predictors of dose. CONCLUSION Patient off-centering closer to the x-ray source resulted in patient magnification in the posteroanterior localizer image, leading to higher tube currents with ATCM and increased DLP. Differences in technologist, arm position, and overscanning also resulted in dose variability.

Testicular Tumors: What Radiologists Need to Know—Differential Diagnosis, Staging, and Management

Cryptorchidism, family history, and infertility are risk factors for testicular cancer. Most testicular cancers occur in young men aged 18-35 years, and seminoma is the most common cell type. Testicular tumors are usually diagnosed at ultrasonography (US) and are staged at computed tomography (CT) or magnetic resonance (MR) imaging. At US, testicular tumors usually appear as a solid intratesticular mass. Because the differential diagnosis includes infarct and infection, correlation with patient history and symptoms is important. At staging CT or MR imaging, retroperitoneal lymph nodes are considered regional lymph nodes, and the greatest nodal diameter is used to distinguish among N1-N3 disease. The right testicular vein drains into the inferior vena cava, and the left testicular vein drains into the left renal vein. Because of venous and lymphatic drainage pathways, retroperitoneal lymph nodes are the initial landing station for testicular cancers. Enlarged lymph nodes in the supraclavicular region, chest, and pelvis are considered distant metastases. Testicular cancer is initially treated with orchiectomy. The patient may then undergo active surveillance, chemotherapy, radiation therapy, or retroperitoneal lymph node resection, depending primarily on the clinical stage. Radiologists play an important role in initial diagnosis, staging, and imaging surveillance of testicular malignancies.

Safety and Quality of 1.5-T MRI in Patients With Conventional and MRI-Conditional Cardiac Implantable Electronic Devices After Implementation of a Standardized Protocol

OBJECTIVE The purpose of this study was to evaluate the safety and diagnostic utility of 1.5-T MRI examinations of individuals with conventional and MRI-conditional cardiac implantable electronic devices (CIEDs). SUBJECTS AND METHODS Patients with a CIED who were referred for MRI were evaluated by radiologists and cardiac electrophysiologists for study participation. CIED interrogation was performed immediately before and after MRI, and cardiac telemetry monitoring was performed during MRI. CIED programming changes, malfunctions, and intraprocedural events were documented. Whether diagnostic questions were answered and whether artifacts related to the CIED were present and negatively affected image interpretation were recorded. RESULTS One hundred thirteen MRI examinations were performed for 104 patients with CIEDs (74 pacemakers [60 conventional, 14 MRI conditional]; 39 implantable cardiac defibrillators). Device reprogramming was required before MRI for 62.8% of studies (71/113). No significant changes in lead parameters were noted during or after MRI. Electromagnetic noise was detected on at least one lead in 7.1% of studies. Three patients reported transient symptoms (one case each of heating at the pocket site, tingling at the pocket site, and palpitations). All images were considered diagnostic for the original clinical query. Artifacts related to CIEDs were described in 3.5% of MRI reports (4/113) and were present only when the pulse generator was included in the FOV. CIED-related artifacts limited evaluation of tissues immediately adjacent to the pulse generator. CONCLUSION Establishment of a multidisciplinary work flow allows individuals with conventional and MRI-conditional CIEDs to safely undergo 1.5-T MRI with diagnostic questions consistently answered.

ACR Appropriateness Criteria Renal Cell Carcinoma Staging

Renal cell carcinoma accounts for 2%-3% of all visceral malignancies. Preoperative imaging can provide important staging and anatomic information to guide treatment decisions. Size of the primary tumor and degree of local invasion, such as involvement of perinephric fat or renal sinus fat, and tumor thrombus in renal veins and inferior vena cava are important detriments to local staging of primary tumor. Both kidneys are assessed for presence of other synchronous lesions. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and application by the panel of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Magnetic resonance imaging of rectal cancer: staging and restaging evaluation

Abstract Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning. The relationship of the tumor to the anal sphincter in addition to the depth of local invasion determines the surgical approach used for resection. High-resolution T2-weighted imaging is the primary sequence used for initial staging. The addition of diffusion-weighted imaging improves accuracy in the assessment of treatment response on restaging scans. Approximately 10%–30% of individuals will experience a complete pathologic response following chemoradiation with no residual viable tumor found in the resected specimen at histopathologic assessment. In some centers, individuals with no residual tumor visible on restaging MR who are thought to be at high operative risk are monitored with serial imaging and a “watch and wait” approach in lieu of resection. Normal rectal anatomy, MR technique utilized for staging and restaging scans, and TMN staging are reviewed. An overview of surgical techniques used for resection including newer, minimally invasive endoluminal techniques is included.

Posttransplantation Lymphoproliferative Disease: Proposed Imaging Classification

Posttransplantation lymphoproliferative disease (PTLD) is the second most common tumor in adult transplant recipients. Most cases of PTLD are attributed to Epstein-Barr virus. Decreased levels of immunosurveillance against this tumor virus as a result of immunosuppressive regimens are thought to account for most cases of PTLD. Histologically, PTLD ranges from relatively benign lymphoid hyperplasia to poorly differentiated lymphoma, and tissue sampling is required to establish the subtype. The frequency of PTLD varies depending on the type of allograft and immunosuppressive regimen. PTLD has a bimodal manifestation, with most cases occurring within the first year after transplantation and a second peak occurring 4-5 years after transplantation. Patients are often asymptomatic or present with nonspecific symptoms, and a mass visible at imaging may be the first clue to the diagnosis. Imaging plays an important role in identifying the presence of disease, guiding tissue sampling, and evaluating response to treatment. The appearance of PTLD at imaging can vary. It may be nodal or extranodal. Extranodal disease may involve the gastrointestinal tract, solid organs, or central nervous system. Solid organ lesions may be solitary or multiple, infiltrate beyond the organ margins, and obstruct organ outflow. Suggestive imaging findings should prompt tissue sampling, because knowledge of the PTLD subtype is imperative for appropriate treatment. Treatment options include reducing immunosuppression, chemotherapy, radiation therapy, and surgical resection of isolated lesions.

Cumulative Radiation Exposure Estimates of Hospitalized Patients from Radiological Imaging

PURPOSE To examine the use of inpatient diagnostic imaging and image-guided procedures to estimate cumulative radiation exposure, radiation exposure based on imaging modality, and compare estimated doses based on patient demographics including age, gender, and diagnoses. METHODS Two hundred consecutive hospitalized adult patients who underwent diagnostic imaging studies at 2 large, affiliated hospitals were identified, and every study in each patients electronic record that took place during a single hospitalization was reviewed. Dose estimates were calculated for each CT, fluoroscopy, nuclear medicine, plain film, and interventional radiology study or procedure based on reported dose length product, published reference values, and conversion factors. Medical records were reviewed to determine patient gender, age, diagnoses, length of stay, admitting service, and time in an intensive care unit (ICU). RESULTS Two hundred inpatients (46.5% male; mean age, 60.4 years) underwent 2,751 imaging studies (79.3% radiographs, 9.7% CT, 6.1% ultrasound, 2.5% interventional radiology, 2.2% MRI, 0.4% nuclear medicine). The mean dose estimate per patient was 14.8 milliSieverts (mSv) and the range was 0 mSv to 130.5 mSv. Mean cumulative dose estimates were significantly higher for patients whose hospitalizations included time in an ICU (17.9 mSv versus 11.3 mSv [P = .01]). CT examinations accounted for 82.1% of the total radiation dose estimate. Eleven patients (5.5%) received radiation dose estimates ≥ 50 mSv, including 2 ≥ 100 mSv. CONCLUSIONS Of imaged inpatients, 62% underwent at least 1 CT and the majority (82.1%) of inpatient radiation exposure was attributable to CT examinations. Mean dose estimate was 14.8 mSv per patient; 5.5% of patients experienced estimated doses ≥ 50 mSv.

Colorectal Cancer Initial Diagnosis: Screening Colonoscopy, Diagnostic Colonoscopy, or Emergent Surgery, and Tumor Stage and Size at Initial Presentation

INTRODUCTION/BACKGROUND Rates of colorectal cancer screening are improving but remain suboptimal. Limited information is available regarding how patients are diagnosed with colorectal cancer (for example, asymptomatic screened patients or diagnostic workup because of the presence of symptoms). The purpose of this investigation was to determine how patients were diagnosed with colorectal cancer (screening colonoscopy, diagnostic colonoscopy, or emergent surgery) and tumor stage and size at diagnosis. PATIENTS AND METHODS Adults evaluated between 2011 and 2014 with a diagnosis of colorectal cancer were identified. Clinical notes, endoscopy reports, surgical reports, radiology reports, and pathology reports were reviewed. Sex, race, ethnicity, age at the time of initial diagnosis, method of diagnosis, presenting symptom(s), and primary tumor size and stage at diagnosis were recorded. Colorectal cancer screening history was also recorded. RESULTS The study population was 54% male (265 of 492) with a mean age of 58.9 years (range, 25-93 years). Initial tissue diagnosis was established at the time of screening colonoscopy in 10.7%, diagnostic colonoscopy in 79.2%, and during emergent surgery in 7.1%. Cancers diagnosed at the time of screening colonoscopy were more likely to be stage 1 than cancers diagnosed at the time of diagnostic colonoscopy or emergent surgery (38.5%, 7.2%, and 0%, respectively). Median tumor size was 3.0 cm for the screening colonoscopy group, 4.6 cm for the diagnostic colonoscopy group, and 5.0 cm for the emergent surgery group. At least 31% of patients diagnosed at the time of screening colonoscopy, 19% of patients diagnosed at the time of diagnostic colonoscopy, and 26% of patients diagnosed at the time of emergent surgery had never undergone a screening colonoscopy. CONCLUSION Nearly 90% of colorectal cancer patients were diagnosed after development of symptoms and had more advanced disease than asymptomatic screening patients. Colorectal cancer outcomes will be improved by improving rates of colorectal cancer screening.

Lessons learned from 118,970 multidetector computed tomographic intravenous contrast material administrations: impact of catheter dwell time and gauge, catheter location, rate of contrast material administration, and patient age and sex on volume of extravasate.

Objectives The aim of this study was to determine the impact of catheter dwell time and gauge, catheter location, rate of contrast material administration, and patient age and sex on volume of extravasate at intravenous contrast-enhanced multidetector computed tomography. Methods Incident reports were reviewed for all extravasation events that occurred in adult patients between March 2006 and December 2009 at 2 institutions. Patient age and sex; catheter dwell time, gauge, and location; rate of contrast material administration; and estimated volume of extravasated contrast material were recorded. Results Three hundred thirty extravasation events were recorded for the 118,970 contrast material administrations (0.3%). Mean volume of extravasated contrast material was statistically significantly less for catheters newly placed in the radiology department, for higher flow rates, for smaller gauge catheters, and for catheters placed in the hand. Mean volume of extravasated contrast material did not vary significantly based on patient age or sex. Conclusions The volume of extravasate was likely to be smaller for smaller-gauge catheters in the hand with higher flow rates and for catheters newly placed in the radiology department.

Performance of Bedside Diagnostic Ultrasound in an Ebola Isolation Unit: The Emory University Hospital Experience

OBJECTIVE Individuals with Ebola virus disease, a contagious and potentially lethal infection, are now being treated in specialized units in the United States. We describe Emory Universitys initial experience, current operating procedures, and ongoing planning with diagnostic ultrasound in the isolation unit. CONCLUSION Ultrasound use has been limited to date. Future planning considerations include deciding what types of ultrasound studies will be performed, which personnel will acquire the images, and which ultrasound machine will be used.