Abdominal Organs Attenuation Values and Abdominal Aortic Calcifications on Virtual and True Noncontrast Images Obtained With Third-Generation Dual-Source Dual-Energy Computed Tomography.

PURPOSE: To evaluate the agreement and correlation between attenuation values and vascular calcification volume for intra-abdominal structures from true noncontrast (TNC) images and those from virtual noncontrast (VNC) images obtained by dual-source dual-energy computed tomography (CT) using a quadriphasic dynamic protocol. METHODS: Seventy-six patients who underwent quadriphasic abdominal CT were retrospectively reviewed. An arterial, portal venous, and 5-minute delayed phase postcontrast series was obtained using dual-source dual-energy CT. Virtual noncontrast images were processed from the arterial, portal venous, and 5-minute delayed phase series. Attenuation values for the liver, pancreas, kidneys, muscle, fat, vertebra, gallbladder, aorta, inferior vena cava, portal vein, and aortic calcification volumes were recorded. Attenuation values for the liver, pancreas, vertebra, and muscle obtained from VNC were adjusted using linear regression. RESULTS: Repeated-measures analysis of variance and Bonferroni multiple-comparison post hoc correction revealed significant differences between TNC and VNC attenuation values for the organs. There was an excellent correlation between the TNC and VNC attenuation values for the liver, pancreas, muscle, vertebra, and fat. The calcification volume was significantly smaller on VNC than on TNC. The adjusted attenuation values estimated by regression equations afforded better approximation. CONCLUSIONS: Abdominal VNC images obtained with third-generation dual-source dual-energy CT cannot replace TNC images without adjustment of the attenuation values.

Angioleiomyoma of the Extremities: Findings on Ultrasonography and Magnetic Resonance Imaging.

OBJECTIVES: The purpose of this study was to describe the features of angioleiomyomas of the extremities on ultrasonography (US) and magnetic resonance imaging (MRI). METHODS: We retrospectively reviewed the US and MRI findings of 29 pathologically confirmed cases of angioleiomyomas of the extremities in 29 patients. Twenty patients underwent only US; 7 patients underwent only MRI; and 2 patients underwent US and MRI. Clinical data and histopathologic specimens were reviewed. RESULTS: There were 19 women and 10 men. The mean patient age was 48.9 years (range, 23-80 years). On US, angioleiomyomas were located primarily in the subcutaneous fat layer (n = 20 [91%]), were oval (n = 17 [77%]), had well-circumscribed margins (n = 22 [100%]), had hypoechoic protrusions on one or both ends (n = 9 [41%]), had a homogeneous echo texture (n = 17 [ 77%]), had posterior acoustic enhancement (n = 20 [91%]), and had color Doppler flow (n = 20 [91%]). On MRI, the masses showed heterogeneous enhancement (n = 7 [88%]) and enhancing structures on one or both ends (n = 4 [50%]) on contrast-enhanced T1-weighted images. CONCLUSIONS: Angioleiomyoma of the extremities is usually a well-circumscribed oval mass with a homogeneous echo texture and occasionally hypoechoic protrusions on US and shows heterogeneous enhancement with occasionally enhancing structures on one or both ends of the mass on MRI. Therefore, it should be included in the differential diagnosis of a soft tissue mass that has protruding structures from one or both ends.

MRI findings for unilateral sternoclavicular arthritis: differentiation between infectious arthritis and spondyloarthritis.

OBJECTIVES: To analyze and identify magnetic resonance imaging (MRI) and clinical findings for the differentiation between infectious arthritis and spondyloarthritis in patients with unilateral sternoclavicular arthritis. MATERIALS AND METHODS: We retrospectively collected and evaluated the magnetic resonance (MR) images of 21 patients diagnosed with unilateral sternoclavicular arthritis, including 12 with infection and nine with spondyloarthritis, between 2004 and 2017. Capsular distension, extracapsular fluid collection, periarticular muscle edema, the prevalence and distribution of bone marrow edema, and the prevalence and size of bone erosions were assessed on the MR images. Clinical data were also reviewed. RESULTS: Capsular distension was more prominent in patients with infectious arthritis than those with spondyloarthritis (p = 0.002); extracapsular fluid collection and periarticular muscle edema were also more common in infectious arthritis than spondyloarthritis (p < 0.001, respectively); moreover, bone erosions were larger in infectious arthritis than spondyloarthritis (p = 0.023). Other findings significantly associated with infectious arthritis included advanced age (p = 0.007), an elevated C-reactive protein (CRP) level (p = 0.001), and erythrocyte sedimentation rate (ESR) (p < 0.001). The prevalence and distribution of bone marrow edema and the prevalence of bone erosions on MRI, the white blood cell count, and sex showed no significant differences between the two groups. CONCLUSIONS: Capsular distension, extracapsular fluid collection, periarticular muscle edema, and the size of bone erosions on MRI, as well as the age, CRP level, and ESR of patients, could be helpful for differentiating infectious arthritis from spondyloarthritis involving the sternoclavicular joint.

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging.

OBJECTIVES: The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). METHODS: The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed. RESULTS: There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images. CONCLUSIONS: Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Ultrasonographic Features of Eccrine Spiradenoma.

The purpose of this series was to evaluate the features of eccrine spiradenoma on ultrasonography (US). We reviewed the clinical data of 8 patients with eccrine spiradenoma who underwent preoperative US at 4 different medical institutions from 2004 to 2016 and analyzed the US features in terms of the tumor location, size, shape, margin, echo texture, echogenicity, posterior acoustic enhancement, calcification, septum, and color Doppler flow. There were 7 female patients and 1 male patient. The mean patient age was 45.6 years (range, 28-60 years). Most of the tumors were located primarily in the subcutaneous fat layer. The mean size of the tumors was 14.3 mm. The masses had a lobular appearance in 7 patients and had a tractlike structure in 3 patients. In 6 patients, the masses had a heterogeneous echo texture. Six cases showed hypoechogenicity with more hypoechoic foci in the masses, and 2 cases showed hypoechogenicity only. Color Doppler flow was evaluated in 7 patients; the blood flow was central and peripheral in 4 patients and only peripheral in 3 patients. All cases showed posterior acoustic enhancement and had well-defined margins. Calcification and septa were not seen in any cases. Eccrine spiradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, a lobulated appearance, occasionally with a tractlike structure, a heterogeneous echo texture, a hypoechoic appearance with internal hypoechoic foci and posterior acoustic enhancement, and shows blood flow in the peripheral portion, with or without blood flow in the central portion.

Periosteal chondroma with spinal cord compression in the thoracic spinal canal: a case report.

Periosteal chondroma is a very unusual cartilaginous neoplasm of the spinal canal. We herein report a case of periosteal chondroma in a 41-year-old male who presented with gait disturbance and paresthesia of both lower extremities. Magnetic resonance (MR) images showed an extradural mass which caused compression of the spinal cord at the T5/6 level. The mass showed iso-signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and nodular and peripheral rim enhancement on post-contrast T1-weighted images. Computed tomography (CT) images showed a mass with punctate calcifications and extension into the left T5/6 neural foramen. MR and CT images showed extrinsic cortical bone erosion of the posterior inferior body of T5 and superior pedicle of T6, bone remodeling with overhanging margins, and sclerosis adjacent to the tumor. The patient underwent a complete excision of the mass by left T5/6 hemi-laminectomy and exhibited complete resolution of his symptoms. Histopathologic examination revealed periosteal chondroma. Tumor recurrence was not recorded during the 18-month follow-up period.

MRI features of calcifying aponeurotic fibroma in the upper arm: a case report and review of the literature.

Calcifying aponeurotic fibroma is a rare soft tissue tumor that occurs in the distal extremities of children and adolescents. We report a case of pathologically proven calcifying aponeurotic fibroma in the left upper arm of a 23-year-old female. Radiographs revealed increased soft tissue density with multiple stippled calcifications in the mid-portion of the patient's left upper arm. Magnetic resonance imaging (MRI) showed a well-defined soft tissue mass with low to intermediate signal intensity on T1-weighted images, heterogeneously low signal intensity on T2-weighted images, and heterogeneous enhancement on fat-suppressed, contrast-enhanced T1-weighted images. Histologically, spindle cell proliferation with scattered calcifications and hyalinization was present. Seven years after surgery, there was no evidence of local recurrence. This is the first report of MRI findings of calcifying aponeurotic fibroma in the upper arm. We also summarize the MRI findings of 16 previously reported cases of calcifying aponeurotic fibroma originating in the upper or lower extremities.

Ultrasonography- or electrophysiology-guided suprascapular nerve block in arthroscopic acromioplasty: a prospective, double-blind, parallel-group, randomized controlled study of efficacy.

PURPOSE: To evaluate the efficacy of ultrasonography-guided (UG) and electrophysiology-guided (EG) suprascapular nerve block (SNB) for arthroscopic acromioplasty with regard to pain relief. METHODS: A prospective, double-blind, randomized controlled clinical trial was performed from June 2007 to April 2010. Patients who were scheduled for elective arthroscopic acromioplasty and who met the inclusion criteria were assigned to 1 of 2 experimental groups (UG or EG SNB) or to 1 blind group (using anatomic landmarks). Before surgery, an SNB was performed with either ultrasonographic or electrophysiologic guidance or with no assistive devices (blind). Variables were collected at 4, 24, 48, and 72 hours postoperatively. RESULTS: Sixty-three patients were initially enrolled in the study, but 11 dropped out for various reasons. In the UG group at 4 hours, the visual analog scale score at rest (30 ± 12.0 v 39 ± 9.9 for EG group and 41 ± 11.8 for blind group) and when the patient was moving (42 ± 15.2 v 52 ± 11.5 for EG group and 53 ± 12.6 for blind group) was significantly decreased compared with the EG and blind groups (P < .05). Opioid consumption during the first 24 hours was significantly reduced in the UG and EG groups (4.3 ± 1.9 mg and 3.8 ± 2.3 mg, respectively) compared with the blind group (5.1 ± 2.2 mg) (P < .05). The visual analog scale score at rest and when the patient was moving; the pain score on the University of California, Los Angeles questionnaire; and the activities of daily living score on the American Shoulder and Elbow Surgeons questionnaire in the EG and UG groups improved more than the values in the blind group over the follow-up intervals (P < .05). Morphine consumption in the EG and UG groups by the first, second, and third days was significantly smaller than that in the blind control group (P < .05). CONCLUSIONS: UG and EG SNB can reduce pain and painkiller consumption for up to 72 hours postoperatively. Ultrasonographic or electrophysiologic guidance is more effective than the blind method of SNB. LEVEL OF EVIDENCE: Level I, randomized controlled trial with significant difference.

Evaluating Biliary Malignancy with Measured and Calculated Ultra-high b-value Diffusion-weighted MR Imaging at 3T.

PURPOSE: Although diffusion-weighted imaging (DWI) with ultra-high b-values is reported to be advantageous in the detection of some tumors, its applicability is not yet known in biliary malignancy. Therefore, this study aimed to evaluate the impact of measured b = 1400 s/mm2 (M1400) and calculated b = 1400 s/mm2 (C1400) DWI on image quality and quality of lesion discernibility using a modern 3T MR system compared to conventional b = 800 s/mm2 DWI (M800). METHODS: We evaluated 56 patients who had pathologically proven biliary malignancy. All the patients underwent preoperative or baseline 3T MRI using DWI (b = 50, 400, 800, and 1400 s/mm2). The calculated DWI was obtained using a conventional DWI set (b = 50, 400, and 800). The tumor-to-bile contrast ratio (CR) and tumor SNR were compared between the different DWI images. Likert scores were given on a 5-point scale to assess the overall image quality, overall artifacts, ghost artifacts, misregistration artifacts, margin sharpness, and lesion discernibility. Repeated-measures analysis of variance with post hoc analyses was used for statistical evaluations. RESULTS: The CR of the tumor-to-bile was significantly higher in both M1400 and C1400 than in M800 (Pa < 0.01). SNRs were significantly higher in M800, followed by C1400 and M1400 (Pa < 0.01). Lesion discernibility was significantly improved for M1400, followed by C1400 and M800 for both readers (Pa < 0.01). CONCLUSION: Using a 3T MRI, both measured and calculated DWI with an ultra-high b-value offer superior lesion discernibility for biliary malignancy compared to the conventional DWI.

Ultrasonographic analysis of subcutaneous angiolipoma.

OBJECTIVE: To describe and analyze the ultrasonographic appearance of subcutaneous angiolipoma in pathology-proven cases. MATERIALS AND METHODS: We retrospectively searched the January 2004 to May 2011 surgical pathology database for cases of pathology-proven angiolipoma. The ultrasonographic findings were analyzed for angiolipoma size, shape, margin, echo texture, echogenicity, acoustic enhancement, calcifications, and color Doppler flow. RESULTS: Of 31 angiolipomas, 19 lesions occurred in an upper extremity, one in a lower extremity, nine in the chest and abdominal wall, and two in the back. The mean tumor size was 17.7 mm. Twenty-five cases (80%) appeared as oval mass and all tumors had well-defined margins. All cases showed hyperechoic; 14 (45%), homogeneous; 17 (55%), heterogeneous. Seven cases (23%) showed blood flow in the mass. Acoustic enhancement and calcification was not shown in any cases. A correct preoperative diagnosis was made in three cases (10%) by ultrasonography. CONCLUSIONS: Most subcutaneous angiolipomas are oval-shaped, have well-defined margins, and hyperechoic appearance on ultrasonography. Although color Doppler flow of subcutaneous angiolipoma is not seen in many cases, it may helpful in differentiating angiolipoma from ordinary subcutaneous lipoma.

Amyloid Arthropathy and Pseudomyopathy Associated With Multiple Myeloma Detected by 18F-Florapronol Amyloid PET/CT.

ABSTRACT: We report a case of amyloid arthropathy and pseudomyopathy with multiple myeloma, detected by amyloid PET/CT using 18F-florapronol. Bone scintigraphy and 18F-FDG PET/CT in a multiple myeloma patient revealed uneven soft tissue uptakes, especially at periarticular areas. The joint capsule and intermuscular fascia showed enhancement on CT, whereas muscle enzymes were normal. These suggested amyloid arthropathy with pseudomyopathy. 18F-Florapronol amyloid PET/CT showed extensive soft tissue uptakes. Amyloid arthropathy and pseudomyopathy were confirmed after biopsy. This is the first report of amyloid PET/CT aiding in the diagnosis of unusual presentation of systemic amyloidosis.

Imaging features of benign solid testicular and paratesticular lesions.

OBJECTIVE: The presence of an intratesticular solid lesion is usually highly suspicious for malignancy. Conversely, most extratesticular solid lesions including paratesticular lesions are benign. The characteristic imaging features of malignant solid testicular lesions are well known, but various unusual causes and imaging features of benign solid testicular lesions can be particularly misleading. Therefore, a careful assessment of solid testicular and paratesticular lesions is warranted. The purpose of this article is to present the clinical and imaging features of the spectrum of benign solid testicular and paratesticular lesions. METHODS: We demonstrate a variety of benign solid testicular and paratesticular lesions and correlate them with pathologic results. RESULTS: Specific the clinical and imaging features of the spectrum of benign solid testicular and paratesticular lesions have been described. CONCLUSIONS: Familiarity with the clinical setting and imaging features of benign solid testicular and paratesticular lesions should facilitate prompt, accurate diagnosis and treatment.

Classification of persistent primitive trigeminal artery (PPTA): a reconsideration based on MRA.

BACKGROUND: Persistent primitive trigeminal artery (PPTA) is the most common permanent carotid-basilar anastomosis. Magnetic resonance angiography (MRA) has become the primary non-invasive imaging technique for evaluation of cerebral vascular anatomy and can provide detailed 3D imaging of intracranial vessels. PURPOSE: To evaluate the usefulness of MRA for the detection of PPTA and to re-classify its variations based on the embryologic types of PcomA and its relationship with the basilar artery and its branches. MATERIAL AND METHODS: Of the total 7329 patients who underwent MRA at our institution from March 2008 through November 2010, we retrospectively analyzed the MRAs of 24 patients with a PPTA. Special attention was given to defining the relationship of the PPTA and the basilar artery with PcomA and to determine the site of origin, size, and course of the PPTA. The PPTA classification included five types based on their anatomic relationship to the neighboring arteries. Clinical features and associated vascular anomalies are also described. RESULTS: Twenty-four (17 women and seven men, 34 ~ 81 years of age, mean age 59.67 years) of the 7329 patients had a PPTA (0.33 %). Eleven cases (45.8%) were classified as type 1, three (12.5%) as type 2, five (20.8%) as type 3, one (4.2%) as type 4, and four (16.7%) as type 5b. Fifteen PPTAs (62.5%) were located on the left side and nine were located (37.5%) on the right side. The basilar artery proximal to the insertion of the PPTA showed severe to moderate hypoplasia in 13 cases (54%). Nine intracranial artery aneurysms were detected in seven (29%) of the 24 study patients. CONCLUSION: This study revealed five types of PPTA and necessitates an adjustment of the previous classification of PPTA on the basis of our MRA examinations. A PPTA should be considered by both the clinician and the radiologist who interpret MR angiography.

Motion Correction of Dual Volume Reconstruction of Three­dimensional Digital Subtraction Angiography for Follow­up Evaluation of Intracranial Coiled Aneurysms.

PURPOSE: To evaluate the usefulness of the "Motion Correction" function of the dual volume-3D-volume-rendering technique (DV-3D-VRT) in follow-up digital subtraction angiography (DSA) of intracranial coiled aneurysms. MATERIALS AND METHODS: This study used data collected from consecutive, follow-up DSAs after the coiling of 64 intracranial aneurysms in 59 patients. We performed subtracted 3D-rotational angiographies (3D-RAs) on all DSAs and obtained DV-3D-VRT images. We then assessed recurrence using DV-3D-VRT images with and without the motion correction functions (MC(+) vs. MC(-)) and observed which method showed better agreement with the reference assessment (using a combination of 2D DSA and TOF MRA images). RESULTS: The recurrence of MC(-) DV-3D-VRT images showed 51.6% (33/64) agreement with the reference assessment, whereas the MC(+) DV-3D-VRT images showed 78.1% (50/64) (P = 0.035, McNemar test). CONCLUSION: Motion correction is a useful complementary imaging technique in evaluating aneurysm recurrence after endovascular embolization. MC(+) DV-3D-VRT image showed higher inter-observer agreement than MC(-) DV-3D-VRT.

Use of preoperative mammography, ultrasonography, and MRI to predict nipple areolar complex involvement in breast cancer.

OBJECTIVE: To identify the predictive factors of cancer invading into the nipple. METHODS: Patients with breast cancer undergoing mastectomy between May 2009 and March 2019 were reviewed retrospectively. Of these, those with breast cancer within 2 cm of the nipple areolar complex on ultrasonography were included in this study. Clinicopathological data of the primary tumor and imaging findings from mammography, ultrasonography, and MRI were compared between cases with and without nipple involvement by cancer. RESULTS: In total, 156 of the 821 patients identified were included in the analysis. Of them, 29 had nipple involvement by cancer. Univariate analysis revealed that the following imaging results were significantly associated with nipple involvement: perineural invasion, lymphovascular invasion, lymph node metastasis; relation type between the tumor and the nipple on ultrasonography; periareolar skin thickening on mammography; and short tumor-nipple distance, continuous enhancement between the nipple and tumor, skin enhancement, and nipple enhancement on MRI. However, on multivariate logistic regression analysis, only invasion type of tumor on ultrasonography and nipple enhancement and short tumor-nipple distance on MRI were significantly correlated with nipple involvement by cancer. CONCLUSION: Imaging findings on preoperative mammography, ultrasonography and MRI are effective predictors for nipple involvement by cancer. ADVANCES IN KNOWLEDGE: Preoperative mammography, ultrasonography, and MRI help predict nipple involvement by breast cancer.

Unusual manifestations of renal cell carcinoma.

The imaging characteristics of renal cell carcinoma (RCC) vary widely, with masses ranging from cystic to solid, from homogeneous to heterogeneous and necrotic, from small to large, and from localized to extensive. Although the usual imaging features of RCC are well known to radiologists, various unusual imaging features can be particularly misleading; therefore, both usual and unusual imaging features should always be carefully assessed. In this pictorial review, we describe the following unusual imaging features: unusual subtypes, unusual tumor growth, unusual underlying disease, multiple and bilateral presentations, hemorrhage and arteriovenous fistula (AVF)-related presentations, and mimicking of benign tumors. Familiarity with the imaging features of both usual and unusual RCCs will facilitate prompt and accurate diagnosis and treatment.

Value of ultrasonographic evaluation for soft-tissue lesions: focus on incidentally detected lesions on CT/MRI.

Soft-tissue lesions of the musculoskeletal system are commonly encountered in clinical practice and often manifest as palpable lesions. Moreover, the increasing use of cross-sectional imaging such as CT or MRI has resulted in the incidental detection of many soft-tissue lesions. Ultrasonography remains the primary imaging investigation for soft-tissue lesions. It has been shown to be helpful in depicting processes involving the soft-tissue lesions on cross-sectional imaging. This article describes the ultrasonographic findings of the most frequently incidentally detected benign and malignant soft-tissue lesions on cross-sectional imaging and suggests the characteristics of such diseases, focusing on the ultrasonographic features that allow accurate diagnosis. Familiarity with the clinical setting and the appearance of soft-tissue lesions on both ultrasonography and cross-sectional imaging can lead to accurate diagnosis and appropriate management of the condition.

Radiation Dose Reduction in Paranasal Sinus CT: With Feasibility of Iterative Reconstruction Technique.

OBJECTIVES: To (1) compare the radiation dose of low-dose computed tomography (CT) to that of standard-dose CT, (2) determine the minimum optimal radiation dose for use in patients who need endoscopic sinus surgery, and (3) assess the reliability of iterative model reconstruction. STUDY DESIGN: Prospective single-institution study. SETTING: Tertiary care center. SUBJECTS AND METHODS: We recruited 48 adults with medically refractory sinusitis. Each patient underwent 4 scans with different CT parameters: 120 kV and 100 mAs (standard dose), 100 kV and 40 mAs (low dose), 100 kV and 20 mAs (very low dose), and 100 kV and 10 mAs (ultra-low dose). All CT scans were reconstructed via filtered back-projection, and ultra-low dose scans were additionally reconstructed through iterative model reconstruction. Radiation dose, image quality, and diagnostic performance were compared among the scans. RESULTS: Radiation doses decreased to 6% (ultra-low dose), 12% (very low dose), and 22% (low dose) of the standard-dose CT. The image quality of low-dose CT was similar to that of standard-dose CT. Ultra-low-dose CT with iterative model reconstruction was inferior to standard-dose CT for identifying anatomic structures, except for the optic nerve. All CT scans had 100% agreement for diagnosing rhinosinusitis. CONCLUSIONS: With low-dose CT, the radiation dose can be decreased to 22% of that of standard-dose CT without affecting the image quality. Low-dose CT can be considered the minimum optimal radiation for patients who need surgery. Iterative model reconstruction is not useful for assessing the anatomic details of the paranasal sinus on CT.

Development of Coronary Vasospasm during Adenosine-Stress Myocardial Perfusion CT Imaging.

Adenosine is a short-acting coronary vasodilator, and it is widely used during pharmacological stress myocardial perfusion imaging. It has a well-established safety profile, and most of its side effects are known to be mild and transient. Until now, coronary vasospasm has been rarely reported as a side effect of adenosine during or after adenosine stress test. This study reports a case of coronary vasospasm which was documented on stress myocardial perfusion CT imaging during adenosine stress test.

Accuracy of pedicle screw insertion using fluoroscopy-based navigation-assisted surgery : computed tomography postoperative assessment in 96 consecutive patients.

OBJECTIVE: Two-dimensional fluoroscopy-based computerized navigation for the placement of pedicle screws offers the advantage of using stored patient-specific imaging data in providing real-time guidance during screw placement. The study aimed to describe the accuracy and reliability of a fluoroscopy-based navigation system for pedicle screw insertion. METHODS: A total of 477 pedicle screws were inserted in the lower back of 96 consecutive patients between October 2007 and June 2012 using fluoroscopy-based computer-assisted surgery. The accuracy of screw placement was evaluated using a sophisticated computed tomography protocol. RESULTS: Of the 477 pedicle screws, 461 (96.7%) were judged to be inserted correctly. Frank screw misplacement [16 screws (3.3%)] was observed in 15 patients. Of these, 8 were classified as minimally misplaced (≤2 mm); 3, as moderately misplaced (2.1-4 mm); and 5, as severely misplaced (>4 mm). No complications, including nerve root injury, cerebrospinal fluid leakage, or internal organ injury, were observed in any of the patients. CONCLUSION: The accuracy of pedicle screw placement using a fluoroscopy-based computer navigation system was observed to be superior to that obtained with conventional techniques.