Ok Hwa Kim

Low-dose CT for patients with clinically suspected acute appendicitis: optimal strength of sinogram affirmed iterative reconstruction for image quality and diagnostic performance

Background As there is increased concern over the radiation exposure particularly in adolescents and young adults, computed tomography (CT) dose reduction is needed in the diagnosis of acute appendicitis. Purpose To evaluate the optimal strength of sinogram affirmed iterative reconstruction (SAFIRE) to obtain the best image quality on a 30-mAs applied low-dose CT (LDCT30mAs) and to compare the diagnostic performances of the LDCT30mAs with different SAFIRE strengths with that of the 100-mAs applied LDCT (LDCT100mAs) for the diagnosis of acute appendicitis. Material and Methods A total of 102 consecutive patients (47 men, 55 women; mean age, 41.2 years; range, 15–82 years) with right lower quadrant pain underwent abdominal-pelvic CT, consisting of arterial phase LDCT100mAs and portal venous phase LDCT30mAs under a fixed 120 kV. LDCT30mAs images were reconstructed separately with five strength levels (S1–S5). Two blinded radiologists recorded scores for the subjective image quality of the LDCT30mAs dataset (S0–S5) and confidence scores for the diagnosis of acute appendicitis on each dataset and LDCT100mAs. CT image noise was measured for each set. Results The study population consisted of 58 patients with confirmed appendicitis and 44 without appendicitis. There was no significant difference in diagnostic performance between LDCT100mAs and LDCT30mAs with any strength for both readers (AUC for reader 1, LDCT30mAs with S0–S5 = 0.97, LDCT100mAs = 0.93, P = 0.0936; for reader 2, LDCT30mAs with S0–S5 = 0.96, LDCT100mAs = 0.97, P = 0.128). The measured noise decreased as the strength increased from S0 to S5 (mean, 20.8 > 17.7 > 15.6 > 13.5 > 11.5 > 9.5, P < 0.0001). However, overall subjective image quality on S3 was better than the other strengths for both readers (S0 < S1 < S2 < S3 > S4 > S5, P < 0.0001). Conclusion Although measured noise declined as SAFIRE strength increased, S3 seems optimal for the best subjective image quality on LDCT30mAs. The diagnostic performance of LDCT30mAs with any strength is comparable to that of LDCT100mAs for the diagnosis of acute appendicitis.

Calcifying Aponeurotic Fibroma: Case Report with Radiographic and MR Features

Calcifying aponeurotic fibroma is a rare, benign fibroblastic tumor. The lesion has a propensity for local invasion and a high recurrent rate. Therefore, accurate preoperative diagnosis and complete excision are important to prevent the recurrence of the tumor after surgical removal. However, radiographic and magnetic resonance imaging findings of calcifying aponeurotic fibroma have been extremely rarely described in the radiology literature. Thus, we report a rare case of calcifying aponeurotic fibroma affecting the dorsal wrist in a 67-year-old man, describe radiographic and MR findings, and discuss the differential diagnosis of the tumor.

Fibromatosis Associated with Silicone Breast Implant: Ultrasonography and MR Imaging Findings

Desmoid type fibromatosis is an uncommon benign disease entity of which its etiology is currently unknown. It constitutes 0.3% of all solid neoplasms, but it is rarely seen in the breast and even more scarcely reported to develop in association with breast implant. We present ultrasonography and magnetic resonance imaging findings of a 29‐year‐old female patient with fibromatosis after breast implant surgery. Knowledge of imaging findings of breast fibromatosis associated with implant will be helpful for accurate diagnosis and appropriate management.

Spinal Meningeal Melanocytoma with Benign Histology Showing Leptomeningeal Spread: Case Report

Meningeal melanocytoma is a rare benign tumor with relatively good prognosis. However, local aggressive behavior of meningeal melanocytoma has been reported, especially in cases of incomplete surgical resection. Malignant transformation was raised as possible cause by prior reports to explain this phenomenon. We present an unusual case of meningeal melanocytoma associated with histologically benign leptomeningeal spread and its subsequent aggressive clinical course, and describe its radiological findings.

Delaminated Tears of the Rotator Cuff: Prevalence, Characteristics, and Diagnostic Accuracy Using Indirect MR Arthrography

OBJECTIVE. The purpose of this study was to evaluate the prevalence, radiologic characteristics, and accuracy of diagnosing delaminated tears at the supraspinatus tendon-infraspinatus tendon (SST-IST) on indirect MR arthrography. MATERIALS AND METHODS. Of 531 consecutive shoulders that underwent indirect MR arthrography, 231 shoulders with tears at the SST-IST were included. On the MR images, delaminated tears at the SST-IST, defined as intratendinous horizontal splitting between the articular and bursal layers of the SST-IST with or without different degrees of retraction between the two layers, were identified and classified into six types. Other radiologic findings of the SST-IST, such as the presence of intramuscular cysts, were evaluated. We used video records of 127 arthroscopic surgeries to determine the diagnostic accuracy of indirect MRI for the detection of the delaminated tears at the SST-IST. RESULTS. On MRI, 56% (129/231) of shoulders with SST-IST tears had delaminated tears. Articular-delaminated full-thickness tears (n = 58) and articular-delaminated partial-thickness tears (n = 64) were the most common types. Approximately 82% (36/44) of articular-delaminated full-thickness tears occurring at the SST were combined with articular-delaminated partial-thickness tears at the IST. SST-IST footprint tears and intramuscular cysts were significantly more common in the shoulders with delaminated tears. The sensitivity and specificity of indirect MR arthrography for detection of delaminated tears were 92% and 94%, respectively. CONCLUSION. On indirect MR arthrography, approximately half of the shoulders with SST-IST tears had delaminated tears. The diagnostic accuracy of indirect MR arthrography for detection of delaminated tears was high.

Postoperative low-dose follow-up computed tomography for patients with stomach cancer: optimal blending ratio of adaptive statistical iterative reconstruction for image quality and diagnostic performance.

Objective To compare the diagnostic performance of adaptive statistical iterative reconstruction applied low-dose computed tomography (CT) (LDCT) with that of the standard-dose CT (SDCT) for local recurrence in patients with stomach cancer. Methods Seventy-nine consecutive patients who had undergone surgical resection for stomach cancer were enrolled. To monitor recurrence, SDCT (120 kilovolt peak [kVp], 200mAs) had been performed. The LDCT (120 kVp, 100 mA s) was taken, and images were reconstructed with 4 levels of adaptive statistical iterative reconstruction (ASIR) blending (0%, 30%, 50%, and 70%). Two blinded radiologists recorded the diagnostic confidence scores for local recurrence in each data set using a 5-point scale. Endoscopic biopsy results served as the reference standard. Receiver operating characteristic (ROC) curve analysis was used to calculate the diagnostic performance. Results The diagnostic performance of LDCT with variable ASIR blending ratios was comparable to that of SDCT (area under ROC curve, 0.727–0.734, 0.687, respectively, P > 0.05). Conclusions The diagnostic performance of ASIR applied LDCT is comparable to that of SDCT.

Desmoplastic fibroma of bone in a toe: radiographic and MRI findings.

Desmoplastic fibroma is a rare benign primary bone tumor that is histologically similar to the soft tissue desmoid tumor. It most often involves the mandible, large long bone or iliac bone. Desmoplastic fibroma in a toe has been extremely rarely reported. Authors report a rare case of desmoplastic fibroma of bone occurring in the distal phalanx of a foot, with descriptions of the radiographic and MRI findings, correlation of the radiologic and pathologic findings, and discussion on the differential diagnosis of the tumor.

Enhancing patterns of breast cancer on preoperative dynamic contrast-enhanced magnetic resonance imaging and resection margin in breast conserving therapy.

BACKGROUND The association between enhancing patterns of preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and resection margins after BCS has not been studied in detail before. OBJECTIVE We investigated the association between surgical outcomes and enhancing patterns observed on DCE-MRI. METHODS 269 enhancing patterns on DCE-MRI scans were selected, and subdivided into the following groups: (1) a single mass-like enhancement, (2) a single non-mass-like enhancement (NME), (3) mass-like enhancing breast cancer with other mass-like enhancing lesions, and (4) mass-like enhancing breast cancer with additional NMEs. Associations between enhancing patterns on DCE-MRI and re-excision rate, size of specimen, and ratio of tumor/specimen were evaluated retrospectively. RESULTS The conversion rate from breast conserving therapy (BCT) to mastectomy as a result of MRI findings was 13.4%, re-excision rate during BCT was 8.2% and excision rate of another suspicious lesion was 7.4%. The single NME group had the highest re-excision rate after BCT (22.2%) (p = 0.02). The ratio of tumor/specimen (p = 0.61) and mean specimen size (p = 0.38) were not influenced by enhancement patterns. The false positive rate and positive predictive values of using DCE-MRI for defining the extension of breast cancer was 22.2% and 71.4%, respectively. CONCLUSION Enhancement patterns on DCE- MRI, especially NME, could increase re-excision rates.

Ultrasonographic findings of the various diseases presenting as calf pain

There are various causes of calf pain. The differential diagnoses affecting the lower leg include cystic lesions, trauma-related lesions, infection or inflammation, vascular lesions, neoplasms, and miscellaneous entities. Ultrasound (US) provide detailed anatomical information of the calf structures, and it offers the ability to confirm, other calf abnormalities, particularly when deep vein thrombosis (DVT) is ruled out. The purpose of this article is to review the causes of a painful calf presenting as DVT and incidental findings found as part of the work-up of DVT, and to provide a broad overview of US findings and clinical features of these pathologies.

Sonographic appearances of juvenile fibroadenoma of the breast.

The purpose of this study was to evaluate characteristic features of juvenile fibroadenoma of the breast on sonography.