Radiology MOC

OBJECTIVE. The CT and MRI features of ovarian torsion are illustrated with gross pathologic correlation. Ovarian enlargement with or without an underlying mass is the finding most frequently associated with torsion, but it is nonspecific. A twisted pedicle, although not often detected on imaging, is pathognomonic when seen. Subacute ovarian hemorrhage and abnormal enhancement is usually seen, and both features show characteristic patterns on CT and MRI. Ipsilateral uterine deviation can also be seen.

CONCLUSION. Diagnostic pitfalls that may mimic ovarian torsion and observations for discriminating them are discussed.

OBJECTIVE. The purpose of this review is to discuss the controversy and lack of consensus in the management of high-risk breast lesions, including flat epithelial atypia, atypical ductal hyperplasia, lobular neoplasia, radial scar, papillary lesions, and mucocelelike lesions, after diagnosis with core needle biopsy.

CONCLUSION. A single uniform approach may not be appropriate for the management of all high-risk breast lesions. A multidisciplinary team may offer individualized treatment options for patients.

OBJECTIVE. The objective of our study was to assess the incidence of associated malignancy when microscopic radial scars and microscopic intraductal papillomas are encountered at percutaneous biopsy for lesions that otherwise reveal benign histopathology.

MATERIALS AND METHODS. A search of the pathology database for the period from December 14, 2006, through December 21, 2009, identified patients with a microscopic radial scar, a microscopic intraductal papilloma, or both at percutaneous biopsy. Patients whose percutaneous biopsy was performed for a lesion that revealed carcinoma or a high-risk pathology result were excluded to avoid confounding bias, as were patients who had only imaging follow-up. Only patients who underwent surgery solely for the study lesion were included. The lesion type that prompted core biopsy, biopsy guidance and device, sample number, and surgical outcomes were recorded. The incidences of benign, high-risk, and malignant pathology findings from surgery were calculated.

RESULTS. The search revealed 35 patients (18 microscopic radial scars, 17 microscopic papillomas) who underwent surgery solely for the study lesion. Stereotactic guidance was used for 15 (43%); ultrasound, for 12 (34%); and MRI, for eight (23%). At surgery, 12 patients (34%) had high-risk histopathology results and 23 (66%) had benign results. No study lesions were upgraded to malignancy.

CONCLUSION. Our study found no evidence of associated malignancy at surgical excision when microscopic radial scars and microscopic intraductal papillomas were encountered at percutaneous biopsy in patients who otherwise had benign histopathology results; thus, routine imaging follow-up may be performed.

OBJECTIVE. A 36-year-old woman presented to her primary care physician with right lower abdominal pain. Her physician subsequently requested a CT to rule out appendicitis. Contrast-enhanced CT was performed and revealed no evidence of appendicitis but showed two subcutaneous ovoid soft-tissue masses anterior to the rectus sheath in the upper pelvis. Pelvic MRI confirmed the two masses, which showed mild enhancement. The objective of this article is to discuss a diagnostic approach to subcutaneous soft-tissue masses in the abdominal wall. Diagnosis was endometriosis of the abdominal wall.

CONCLUSION. Integrating salient imaging findings with clinical history is crucial when approaching the diagnosis of subcutaneous soft-tissue masses. The diagnosis of endometriosis should be entertained when soft-tissue masses are seen in the distribution of a cesarean section scar in a woman of reproductive age. Pain, particularly with a cyclic pattern, is highly suggestive of endometriosis. If endometriosis is suspected on CT or ultrasound, MRI can be performed for further evaluation. Definitive diagnosis is made with biopsy. Because subcutaneous nodules are so amenable percutaneous biopsy, imaging features, although of interest, are somewhat ancillary to the diagnostic workup.

OBJECTIVE. The purpose of this essay is to highlight the clinical features and imaging findings associated with different types of nonthrombotic pulmonary embolism.

CONCLUSION. Nonthrombotic pulmonary embolism is an infrequent condition with various causes that can be life-threatening pathologic conditions. The entity presents a diagnostic challenge because of the low specificity of clinical symptoms and imaging signs. Awareness of the imaging features of nonthrombotic pulmonary embolism facilitates correct diagnosis and leads to appropriate patient care.

OBJECTIVE. We tested a new MDCT technical protocol, combining IV and intravesical positive contrast agent and intravaginal neutral contrast agent, that optimizes exploration of urogenital fistulas. We examined three patients (four CT examinations in total) with this technique and proved that a preexisting subtle ureterovaginal fistula that was under treatment was still present, though clinically silent.

CONCLUSION. The proposed MDCT examination protocol provides important information to help detect subtle urogenital fistulas.

OBJECTIVE. The purposes of this study were to assess chronologic changes in normal growth plate after radiofrequency-induced thermal injury and to evaluate the feasibility of MRI for revealing alteration of the growth plate.

MATERIALS AND METHODS. Radiofrequency ablation was performed on the right proximal tibia of 13 8-week-old New Zealand White rabbits. An 18-gauge cooled-tip electrode with a 5-mm active tip was placed distal to the physis under fluoroscopic guidance. MRI, including T1- and T2-weighted images, gradient-recalled echo images, and contrast-enhanced T1-weighted images, was performed 2, 4, and 12 weeks after ablation. Rabbits were sacrificed 2 (n = 4), 4 (n = 4), and 12 weeks (n = 5) after ablation. The sequential changes in the ablated zone, the injured physis, and the nonablated portion of the physis were correlated between MRI features and histologic results.

RESULTS. Diameter of the nonenhancing lesion on MR images strongly correlated with the size of the region of coagulation necrosis at gross examination. The intraclass correlation coefficients were 0.98 and 0.94 for the long and short axes (p < 0.001). On gradient-recalled echo images, physial conspicuity was less in the injured physis than in the nonablated portion and less in the ablated than the control tibia. Physial conspicuity was graded for comparison with physial thickness at microscopic examination. The thickness of the physis was less in the ablated than in the control tibia 4 and 12 weeks after treatment (p < 0.05, paired Student t test). The cartilage column of the injured physis was delaminated 2 weeks after treatment, and a bone bridge through the injured physis was detected at 4 weeks.

CONCLUSION. Radiofrequency-induced thermal injury causes early closure of the physis. MRI can depict the extent of radiofrequency-induced thermal injury and alterations in the physis that lead to early closure.

OBJECTIVE. The purpose of our study was to compare the accuracy of 3D fat-suppressed isotropic turbo spin-echo (TSE) sequences using sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) with 2D conventional MRI at 3 T in determining meniscal tear types.

MATERIALS AND METHODS. Sixty-nine patients with arthroscopically confirmed meniscal tears underwent MRI with 2D sequences and 3D TSE SPACE. Images were retrospectively analyzed by two reviewers and correlated with arthroscopic findings. Meniscal tears were classified into one of eight types: horizontal, longitudinal, radial, root, flap, oblique, complex, and bucket-handle. For every type of tear, sensitivity, specificity, and interobserver agreement were calculated.

RESULTS. Mean sensitivities and specificities on 3D TSE SPACE versus 2D sequences were as follows: for radial tears, 77% and 93% versus 68% and 90%; for flap tears, 73% and 96% versus 54% and 85%; for horizontal tears, 85% and 91% versus 78% versus 87%; for longitudinal tears, 50% and 97% versus 72% and 96%; and for root tears, 88% and 99% versus 81% and 99%. The specificity for flap tears was statistically higher on 3D TSE SPACE than 2D sequences. Interobserver agreements were higher on 3D TSE SPACE than 2D sequences for radial, flap, and longitudinal tears.

CONCLUSION. In categorizing meniscal tears, 3D TSE SPACE has higher specificity for flap tears than 2D conventional sequences. However, there is no significant difference between 2D conventional sequences and 3D TSE SPACE except for flap tears.

OBJECTIVE. Carpal tunnel syndrome (CTS) represents one of the most prevalent peripheral entrapment mononeuropathies. The purpose of our study was to assess the potential correlation between intraneural hypervascularization, flexor retinaculum bowing, and median nerve cross-sectional area and the severity of CTS in cases confirmed by nerve conduction study.

SUBJECTS AND METHODS. Sixty consecutive patients with classic or probable symptoms of CTS were enrolled in the study. A control group consisting of 27 healthy volunteers who were never diagnosed with CTS or had any symptoms of CTS was recruited among institution employees. All symptomatic patients were initially examined by a hand surgeon and subsequently referred for sonographic and electrophysiologic examinations.

RESULTS. A total of 90 wrists (in 60 patients) were included in the study. Twenty-eight (31.1%) had mild CTS, 33 had moderate disease, and 29 had severe disease. We detected significant correlation between median nerve hypervascularization and the severity of CTS (p = 0.01, logistic regression) for moderate CTS and (p = 0.04) for severe disease. We also detected a significant correlation in flexor retinaculum bowing and median nerve cross-sectional area with increase in the severity of CTS (p < 0.001 and < 0.008; chi-square test and analysis of variance, respectively).

CONCLUSION. Our study suggests that the severity of CTS strongly correlates with color Doppler sonography findings, and this technique may represent a reliable complementary tool in CTS examination.

OBJECTIVE. The purpose of this article is to establish 18F-FDG metabolic imaging parameters to differentiate benign and malignant tumors of the parotid gland.

MATERIALS AND METHODS. Forty-nine patients with increased FDG uptake in the parotid gland were selected for the study group (29 men and 20 women; mean age, 63.14 ± 12.32 years). Another 49 patients without head and neck malignancies were selected as the control group (24 men and 25 women; mean age, 65.80 ± 11.51 years); they did not have a parotid lesion or increased FDG uptake in the parotid gland. Maximum standardized uptake value (SUVmax) was obtained for all patients. Metabolic tumor volume and total glycolytic activity were measured in patients with a discrete parotid lesion (n = 24). Nonparameteric Student t test (Mann-Whitney U test) was performed for between-group analysis.

RESULTS. The median SUVmax of the increased diffuse uptake (2.55; interquartile range [IQR], 1.03–4.07) was significantly lower than the median SUVmax of tumors (8.48; IQR, 1.46–15.5) (p < 0.01). The median SUVmax of malignant tumors (11.8; IQR, 4.45–19.15) was significantly (p < 0.05) higher than that of benign tumors (6.4; IQR, 3.4–9.0). There was significant difference (p = 0.003) in the median metabolic tumor volume for malignant tumors (8.9; IQR, 5.1–25.5) and benign tumors or lesions (1.4; IQR, 1.00–2.9). Similar results were found for total glycolytic activity for malignant tumors (67.9; IQR, 24.2–137.6) and benign tumors or lesions (8.4; IQR, 3.9–13.6) (p = 0.002).

CONCLUSION. FDG PET/CT SUVmax, metabolic tumor volume, and total glycolytic activity are imaging parameters to differentiate benign and malignant tumors of the parotid gland.

OBJECTIVE. The purpose of this study was to investigate with immunohistochemical validation whether dynamic contrast-enhanced MRI with small-molecule contrast medium is useful for monitoring the effects of the multikinase inhibitor sorafenib on prostate carcinomas in rats.

MATERIALS AND METHODS. Copenhagen rats (n = 20) into which prostate carcinoma (MAT-Ly-Lu-B2) had been implanted subcutaneously were imaged on the day of implantation and 7 days later with 3-T dynamic gadobutrol-enhanced MRI. The therapy group (n = 10) received daily administration of 10 mg/kg body weight sorafenib. Quantitative measurements of tumor perfusion, tumor vascularity, and permeability–surface area product were calculated with a two-compartment model. Dynamic contrast-enhanced MRI values were correlated with immunohistochemical results for validation.

RESULTS. Tumor perfusion in sorafenib-treated prostate carcinoma declined significantly from day 0 to day 7 (47.9 ± 36.8 mL/100 mL/min to 24.4 ± 18.6 mL/100 mL/min; p < 0.05). No significant effect on permeability–surface area product was observed in either the therapy or the control group (p > 0.05). Tumor vascularity decreased significantly (p < 0.05) from day 0 to day 7 under sorafenib treatment (15.6% ± 11.4% to 5.4% ± 2.1%). Immunohistochemical analysis revealed significantly lower tumor vascularity in the therapy than in the control group (rat endothelial cell antigen 1, 74.4 ± 16.9 cells vs 197 ± 75.4 cells; p < 0.05). In sorafenib-treated tumors, significantly more apoptotic cells (terminal deoxynucleotidyl transferase–mediated nick end labeling, 6923 ± 3761 vs 3167 ± 1500; p < 0.05) and significantly fewer proliferating cells (Ki-67, 10,198 ± 3064 vs 15,003 ± 3674; p < 0.05) were observed than in the control group. Modest but significant correlations were observed between tumor perfusion and immunohistochemical tumor cell apoptosis (r = –0.56; p < 0.05) and between tumor perfusion and immunohistochemical tumor vascularity (r = 0.56; p < 0.05).

CONCLUSION. Tumor perfusion quantified with gadobutrol-enhanced dynamic contrast-enhanced MRI can be used as a noninvasive surrogate parameter for monitoring the antiangiogenic, antiproliferative, and proapoptotic effects of sorafenib on prostate carcinoma allografts as validated with immunohistochemical analysis.

OBJECTIVE. The purpose of our study was to compare the effects of IV iohexol and iopamidol on renal function in outpatients undergoing CT.

SUBJECTS AND METHODS. We performed a prospective, double-blind, randomized clinical trial of 389 adults with low risk for contrast-induced nephropathy, comparing IV iohexol with iopamidol (300 mg I/mL). Serum creatinine (SCr) concentration was measured at baseline and 2 and 3 days after contrast administration. A noninferiority analysis was planned to compare the mean maximum SCr change from baseline between subject groups. Contrast-induced nephropathy rates (three definitions) for both contrast agents were compared as a secondary end point.

RESULTS. One hundred ninety and 199 subjects received iohexol and iopamidol, respectively. The mean change in SCr from baseline using the maximum day 2 or 3 measurement was 0.07 ± 0.12 mg/dL (95% CI, 0.05—0.09 mg/dL) for the iohexol group and 0.05 ± 0.12 mg/dL (95% CI, 0.03—0.07 mg/dL) for the iopamidol group. The difference between contrast agents with respect to the mean change in SCr from baseline was –0.02 ± 0.12 mg/dL (95% CI, –0.045 to 0.003 mg/dL; p = 0.08). Contrast-induced nephropathy rates were not statistically different using any definition.

CONCLUSION. Although our results were unable to show absolute noninferiority of iohexol compared with iopamidol because of a very small difference in increase in mean SCr from baseline (using a noninferiority margin of 0.04 mg/dL), this difference is likely of minimal or no clinical importance in outpatients undergoing CT with low risk for contrast-induced nephropathy.

OBJECTIVE. Patients presume safety in radiologic services, but the potential to do harm exists in every area of imaging. Radiology department personnel need to understand basic regulatory requirements for safety and how to promote and improve safety in the future.

CONCLUSION. This article reviews key safety metrics that we think are relevant to radiology and discusses how to define the measures and how we are attempting to translate the metrics into a culture of safety.