Search

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.

Diverticulosis remains the commonest cause for acute lower gastrointestinal tract bleeding (GIB). Conservative management is initially sufficient for most patients, followed by elective diagnostic tests. However, if acute lower GIB persists, it can be investigated with colonoscopy, CT angiography (CTA), or red blood cell (RBC) scan. Colonoscopy can identify the site and cause of bleeding and provide effective treatment. CTA is a noninvasive diagnostic tool that is better tolerated by patients, can identify actively bleeding site or a potential bleeding lesion in vast majority of patients. RBC scan can identify intermittent bleeding, and with single-photon emission computed tomography, can more accurately localize it to a small segment of bowel. If patients are hemodynamically unstable, CTA and transcatheter arteriography/embolization can be performed. Colonoscopy can also be considered in these patients if rapid bowel preparation is feasible. Transcatheter arteriography has a low rate of major complications; however, targeted transcatheter embolization is only feasible if extravasation is seen, which is more likely in hemodynamically unstable patients. If bleeding site has been previously localized but the intervention by colonoscopy and transcatheter embolization have failed to achieve hemostasis, surgery may be required. Among patients with obscure (nonlocalized) recurrent bleeding, capsule endoscopy and CT enterography can be considered to identify culprit mucosal lesion(s). 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.

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. 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.

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.

This review summarizes the relevant literature regarding imaging of suspected diverticulitis as an etiology for left lower quadrant pain, and imaging of complications of acute diverticulitis. The most common cause of left lower quadrant pain in adults is acute sigmoid or descending colonic diverticulitis. Appropriate imaging triage for patients with suspected diverticulitis should address the differential diagnostic possibilities and what information is necessary to make a definitive management decision. Patients with diverticulitis may require surgery or interventional radiology procedures because of associated complications, including abscesses, fistulas, obstruction, or perforation. As a result, there has been a trend toward greater use of imaging to confirm the diagnosis of diverticulitis, evaluate the extent of disease, and detect complications before deciding on appropriate treatment. Additionally, in the era of bundled payments and minimizing health care costs, patients with acute diverticulitis are being managed on an outpatient basis and rapid diagnostic imaging at the time of initial symptoms helps to streamline and triage patients to the appropriate treatment pathway. 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.

Arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) are the vascular accesses of choice for long-term hemodialysis. Strategies to establish and maintain functioning AVFs and AVGs are essential. In addition to clinical evaluation, ultrasound plays a critical role in the evaluation and maintenance of AVFs and AVGs. AVFs have a high rate of failure to mature which can be reliably diagnosed with ultrasound. Treatable etiologies of the failure to mature can often be diagnosed with ultrasound. Causes of secondary AVG failure can also be diagnosed with ultrasound and treated. AVGs have a relatively short functional life expectancy due to a high rate of AVG thrombosis. Ultrasound is a safe, noninvasive way to diagnose vascular stenosis in both AVFs and AVGs prior to thrombosis, potentially saving the access. Routine surveillance ultrasound of asymptomatic AVFs and AVGs is controversial with conflicting studies on its benefit. Routine surveillance ultrasound of AVFs and AVGs is not common practice.

Palpable abdominal masses may arise from the abdominal cavity or the abdominal wall. The differential diagnosis is broad for each variant ranging from benign lipomas, inflammatory processes, to malignant tumors. The imaging approach to diagnosis varies by location. For intra-abdominal masses, contrast-enhanced CT and ultrasound examination have demonstrated accuracy. For abdominal wall masses, which may arise from muscle, subcutaneous tissue, or connective tissue, MRI, CT, and ultrasound all provide diagnostic value. This publication reviews the current evidence supporting the imaging approach to diagnosis of palpable abdominal masses for two variants: suspected intra-abdominal neoplasm and suspected abdominal wall masses. 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.

This review summarizes the relevant literature regarding imaging of suspected diverticulitis as an etiology for left lower quadrant pain, and imaging of complications of acute diverticulitis. The most common cause of left lower quadrant pain in adults is acute sigmoid or descending colonic diverticulitis. Appropriate imaging triage for patients with suspected diverticulitis should address the differential diagnostic possibilities and what information is necessary to make a definitive management decision. Patients with diverticulitis may require surgery or interventional radiology procedures because of associated complications, including abscesses, fistulas, obstruction, or perforation. As a result, there has been a trend toward greater use of imaging to confirm the diagnosis of diverticulitis, evaluate the extent of disease, and detect complications before deciding on appropriate treatment. Additionally, in the era of bundled payments and minimizing health care costs, patients with acute diverticulitis are being managed on an outpatient basis and rapid diagnostic imaging at the time of initial symptoms helps to streamline and triage patients to the appropriate treatment pathway. 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.

The purpose of this study was to assess the diagnostic accuracy of effective atomic number maps reconstructed from dual-energy contrast-enhanced data for discriminating between nonenhancing renal cysts and enhancing masses.Two hundred six patients (128 men, 78 women; mean age, 64 years) underwent a CT renal mass protocol (single-energy unenhanced and dual-energy contrast-enhanced nephrographic imaging) at two different hospitals. For each set of patients, two blinded, independent observers performed measurements on effective atomic number maps from contrast-enhanced dual-energy data. Renal mass assessment on unenhanced and nephrographic images, corroborated by imaging and medical records, was the reference standard. The diagnostic accuracy of effective atomic number maps was assessed with ROC analysis.Significant differences in mean effective atomic numbers (ZNonenhancing renal cysts, including hyperattenuating cysts, can be discriminated from enhancing masses on effective atomic number maps generated from dual-energy contrast-enhanced CT data. This technique may be of clinical usefulness when a CT protocol for comprehensive assessment of renal masses is not available.

The purpose of the study is to differentiate granulomatous prostatitis (GP) from high-grade prostate cancer (PCa) based on clinical findings and imaging characteristics on multiparametric MRI (MP-MRI). Pathology from patients undergoing MRI/US fusion-guided prostate biopsies between 2014 and 2015 was reviewed. Five patients with biopsy proven GP were identified as well as 15 patients with biopsy-proven Gleason score ≥4 + 3 = 7 PCa. Patients were matched for age, serum PSA level, and prebiopsy-assigned MP-MRI cancer suspicion scores. MP-MRI studies were reviewed to identify findings that would differentiate GP from PCa in patients who had equally high suspicion scores based upon imaging characteristics. All five patients with GP on MR/US fusion-targeted biopsies were assigned a PIRADS 4 or 5 suspicion score. There were equally high suspicion scores on MP-MRI for both groups (p = 0.57). Re-evaluation of the MRI characteristics of the 5 GP patients and 15 matched controls who had pathologically proven Gleason score ≥4 + 3 = 7 PCa on targeted biopsy demonstrated statistically lower mean ADC values within the index targeted lesion for PCa vs. GP (p = 0.002) Qualitatively, no patients with GP on biopsy had imaging evidence of higher-staged disease, while 33% of patients in the high-risk PCa cohort demonstrated at least one high-stage feature (p = 0.003). Patients with GP routinely have MRIs with moderate to high levels of suspicion for harboring PCa. Re-evaluation of these patients’ imaging demonstrated characteristics including significantly higher ADC values and absence of high-stage features, which may help differentiate areas of GP from PCa in the future.

The purpose of this study was to compare the diagnostic performance of four radiographic signs of gastric band slippage: abnormal phi angle, the "O sign," inferior displacement of the superolateral gastric band margin, and presence of an air-fluid level above the gastric band.A search of the electronic medical record identified 21 patients with a surgically proven slipped gastric band and 63 randomly-selected asymptomatic gastric band patients who had undergone barium swallow studies. These studies were evaluated for the four signs of band slippage by two independent radiologists who were blinded to clinical data. Sensitivity, specificity, and positive and negative predictive values were calculated for each radiographic sign of band slippage. Interobserver agreement between radiologists was assessed using the Fleiss kappa statistic.In evaluating for gastric band slippage, an abnormal phi angle greater than 58° was 91-95% sensitive and 52-62% specific (κ = 0.78), the O sign was 33-48% sensitive but 97% specific (κ = 0.84), inferior displacement of the superolateral band margin by more than 2.4 cm from the diaphragm was 95% sensitive and 97-98% specific (κ = 0.97), and the presence of an air-fluid level was 95% sensitive and 100% specific (κ = 1.00).We report two previously undescribed radiographic signs of gastric band slippage that are both sensitive and specific for this important surgical complication and recommend that these signs should be incorporated into the imaging evaluation of gastric band patients.

To determine whether the use of a multiple arterial phase imaging technique provides adequate image quality in patients experiencing transient severe motion (TSM) in the arterial phase on abdominal magnetic resonance (MR) images obtained with gadoxetate disodium.This retrospective study was approved by the institutional review board and was compliant with HIPAA. The requirement to obtain informed consent was waived. Five hundred forty-nine consecutive MR examinations were evaluated, 345 performed with gadoxetate disodium and 204 performed with gadobenate dimeglumine. All examinations included single-breath-hold triple arterial phase acquisition. Five radiologists blinded to the contrast material rated motion on a scale of 1 (no motion) to 5 (nondiagnostic images) for the precontrast phase, the three arterial phases, the portal venous phase, and the late dynamic phase. Adequacy of late hepatic arterial timing was also rated for the each of the three arterial phases. Mean motion scores were compared by using the Wilcoxon signed rank test. The number of patients with TSM, as well as the number of those with "adequate" arterial phases, was compared with the χ(2) or Fisher exact test, as appropriate.Mean motion scores in all three arterial phases in the gadoxetate disodium cohort were significantly worse than those in the gadobenate dimeglumine cohort (P.005). TSM occurred at a higher rate with gadoxetate disodium than with gadobenate dimeglumine (10.7% [37 of 345 examinations] vs 0.5% [one of 204 examinations], P.001). However, 30 of 37 examinations affected by TSM had at least one well-timed arterial phase with a mean motion score of 3 or less and were thus considered adequate.Use of single-breath-hold multiple arterial phase acquisition in abdominal MR imaging with gadoxetate disodium recovers most arterial phases that would otherwise have been compromised by transient motion.

Barium enema studies continue to provide important and unique information to clinicians in an era of more advanced cross-sectional imaging.

To determine whether placement of marking coils at biopsy of small renal neoplasms to facilitate localization at subsequent radiofrequency (RF) ablation is safe and can reduce fluoroscopy time during the ablative procedure.This retrospective study was approved by the hospital institutional review board and was compliant with HIPAA. The requirement to obtain informed consent was waived. A search of the renal RF ablation database (235 patients) identified 23 consecutive patients who had a marking coil placed at biopsy of a renal neoplasm (coil group) and 23 patients who did not have a marking coil placed at biopsy (control group). The patients were matched for tumor characteristics, including size, parenchymal position, location in the kidney, and laterality. All patients underwent subsequent RF ablation. The authors compared computed tomographic (CT) fluoroscopy times and technical success rates between the two groups. Statistical analyses were performed by using a single-tailed paired t test for comparison of CT fluoroscopy times, a two-tailed paired t test for comparison of age and tumor size, and a single-tailed McNemar test for comparison of the technical success rate of ablation.The mean CT fluoroscopy time for the RF ablation procedure was 28 seconds ± 11.7 (standard deviation) for the coil group and 66 seconds ± 85.8 for the control group (P = .025). There was no significant difference in the technical success rates of renal RF ablation.For small renal neoplasms that are poorly visualized at unenhanced CT, placement of a metallic marking coil at biopsy facilitates tumor localization, thus reducing CT fluoroscopy time and radiation dose for subsequent RF ablation procedures.

Optimized pretreatment staging of bladder urothelial carcinoma is essential in guiding appropriate treatment. This staging process relies heavily on tissue pathology from transurethral resection of bladder tumor as well as imaging for diagnosis of local, regional, nodal, or distant visceral spread. Accurate preoperative staging is critical for appropriate treatment decision making and patient counseling as these are based on the extent of disease involvement, largely classifying the cancer as having local, regional, or distant spread. Currently, the gold standard of transurethral resection of bladder tumor followed by computed tomography imaging with intravenous contrast provides excellent staging specificity in cases of more advanced bladder cancers with suspicion of spread; however, this often under stages patients that can lead to adverse oncologic outcomes in these patients undergoing radical cystectomy. Incorporation of novel imaging modalities including multiparametric magnetic resonance imaging and positron emission tomography imaging have shown promise in improving accuracy of staging for both local and distant disease in patients with bladder urothelial carcinoma.

The purpose of this article is to determine whether there is a dose-toxicity relationship between gadoxetate disodium and transient severe respiratory motion artifact.Gadoxetate disodium-enhanced MRI studies (559 studies of 559 patients) using a fixed 20-mL (2 mL/s; n = 112) or 10-mL (1-2 mL/s; n = 447) volume at two health systems were included (dose range, 0.05-0.42 mL/kg; mean, 0.15 mL/kg; above-label dosing, 479 [86%]). Each dynamic phase was assigned a respiratory motion score from 1 (none) to 5 (nondiagnostic). Examinations with an unenhanced score of 1-2, arterial score of 4-5, and venous or late-dynamic scores of 1-3 were labeled as transient severe respiratory motion artifact. Stepwise multivariate logistic regression was performed.The overall incidence of transient severe respiratory motion artifact was 12% (67/559; site 1, 15% [35/232]; site 2, 9.8% [32/327]). The administered volume of contrast material had a statistically significant effect (20 mL, 20% [22/112] vs 10 mL, 10%, [45/447]; multivariate p = 0.01; odds ratio, 2.1 [20 vs 10 mL]; 95% CI, 1.2-3.7). There was no dose-toxicity relationship for dose-by-weight (p = 0.61 [multivariate]) or above-label dosing (p = 0.88 [univariate]; 13% [10/80] rate for at- or below-label dosing vs 12% [57/479] rate for above-label dosing). Chronic obstructive pulmonary disease was the only non-dose-related predictor in the multivariate model (p0.0001; OR, 5.1 [95% CI, 2.5-11.5]; 39% [12/31] vs 10% [55/528]).Gadoxetate disodium-associated transient severe respiratory motion artifact is significantly more common after 20-mL administration (2 mL/s) and occurs significantly more often in patients with chronic obstructive pulmonary disease. The volume-related effect suggests a nonallergiclike mechanism.

SUMMARY: We report a case of a thermal burn that occurred during MR imaging likely caused by invisible silver-embedded microfibers in the fabric of an undershirt. As the prevalence of fabric containing nondetectable metallic microfiber increases in athletic and “tech” clothing, the importance of having patients change into safe facility-provided garments before MR imaging is emphasized.