Accuracy of specific free air distributions in predicting the localization of gastrointestinal perforations.

PURPOSE: To evaluate the role of specific distributions of free air in predicting the location of gastrointestinal (GI) tract perforation. MATERIALS AND METHODS: One hundred and fifteen patients with surgically proven GI tract perforation between January 2015 and June 2019 were included in the study. The site of perforation was based on surgical findings in all cases. Two radiologists retrospectively interpreted the computed tomography (CT) images of these patients for extraluminal free air distribution. Perforation sites were demonstrated intraoperatively in all cases and were categorized as follows: stomach and duodenum, jejunum and ileum, proximal colon (cecum, ascending colon, and transverse colon), distal colon (descending colon and sigmoid colon), rectum, and appendix. RESULTS: There were 79 male and 36 female patients with a mean age of 56.4 years. Periportal, perihepatic, and perigastric free air were statistically significant in predicting gastroduodenal perforation. Mesenteric free air was significant in predicting both small bowel and distal colon perforations. Pelvic free air was statistically significant in distal colon perforations. Periappendiceal free air was found to be a strong predictor of acute perforated appendicitis. CONCLUSION: Specific free air distributions may help to predict the site of gastrointestinal perforation, which would change the treatment plan.

Cross-sectional areas of rectus abdominis and psoas muscles reduces following surgery in rectal cancer patients.

PURPOSE: To evaluate the trophic changes in rectus abdominis and psoas muscles in patients who underwent open or laparoscopic rectum resection for rectal cancer. METHODS: We retrospectively analyzed preoperative staging computerized tomographies (CT) and postoperative first oncological follow-up CTs of the patients who underwent low anterior resection (LAR) for rectal cancer from 2010 through 2015. We measured cross-sectional area of left and right rectus abdominis muscles from two levels (above and below umbilicus) where they are widest and psoas muscle at mid-level of the fourth lumbar vertebral body in axial CT images and compared preoperative and postoperative measurements. We investigated the effects of age, sex, administration of preoperative chemoradiotherapy (CRT), type of surgery (open or laparoscopic), or construction of a diverting ileostomy on cross-sectional muscle area changes. RESULTS: After applying inclusion and exclusion criteria 60 patients found to be eligible for the study. Muscle areas of all measurement sites were reduced postoperatively compared to paired preoperative values. There was no significant effect of age, sex, administration of preoperative CRT, type of surgery (open or laparoscopic), or construction of a diverting ileostomy to muscle cross-sectional area reductions. CONCLUSION: Cross-sectional areas of the rectus abdominis and the psoas muscles of rectal cancer patients reduces following rectum resection which indicates atrophy of these muscles. Clinicians should be aware of this problem and focus on prevention of muscle atrophy during the treatment of rectal cancer patients.

Manual and semi-automated computed tomography volumetry significantly overestimates the right liver lobe graft weight: a single-center study with adult living liver donors.

PURPOSE: Preoperative evaluation of donor liver volume is indispensable in living donor liver transplantation to ensure sufficient residual liver and graft-to-recipient weight ratio. This study aims to evaluate the accuracy of two computed tomography (CT) volumetry programs, an interactive manual and a semi-automated one, in the preoperative estimation of the right lobe graft weight. METHODS: One hundred and nine right liver lobe living donors between January 2008 and January 2020 were enrolled in this retrospective study. Two radiologists measured the liver graft volumes independently using manual and semi-automated CT volumetry, and the interaction time was recorded. Actual graft weight (AGW) measured intraoperatively served as the reference standard. The paired samples t-test was used to compare the estimated graft weight (EGW) and the AGW. Inter-user and inter-method agreements were assessed with Bland-Altman plots. RESULTS: Both manual and semi-automated CT volumetry significantly overestimated the graft weight (EGW manual: 893 ± 155 mL vs. AGW manual: 787 ± 128 g, P < 0.001, EGW semi-automated: 879 ± 143 mL vs. AGW semi-automated, P < 0.001). The junior radiologist measured higher volumes than the senior radiologist with either method (P < 0.001). The Bland-Altman analysis revealed mean difference and standard deviation for inter-method agreement of 7 ± 48 cc for the senior radiologist, and 34 ± 54 cc for the junior radiologist. The mean difference and standard deviation for inter-method agreement was 63 ± 59 cc in manual volumetry and 22 ± 38 cc in semi-automated volumetry. The mean interaction time was 27.3 ± 14.2 min for manual volumetry and 6.8 ± 1.4 min for semi-automated volumetry (P < 0.001). CONCLUSION: Both manual and semi-automated CT volumetry significantly overestimated the right liver graft weight, while semi-automated volumetry significantly reduced the interaction time.

Multimodality imaging and histopathology of metaplastic breast cancer

Metaplastic breast cancer (MBC) is a rare subtype of invasive breast cancer characterized by mixed epithelial and mesenchymal differentiation. Commonly seen subtypes include squamous cell carcinoma, spindle cell carcinoma, and metaplastic carcinoma with heterologous mesenchymal differentiation. MBC tends to have a more aggressive clinical presentation, higher metastatic potential, higher rates of local recurrence, and a worse prognosis compared with invasive breast carcinoma of no special type. Most MBCs are triple-negative breast cancers, which explains their resistance to most systemic therapies. Therefore, accurately diagnosing MBC early is crucial for deciding the treatment strategy and predicting the prognosis. In this pictorial essay, the imaging findings of MBC in different modalities and the histopathologic features of its subtypes are reviewed.

Diagnostic performance of magnetic resonance imaging in preoperative local staging of rectal cancer after neoadjuvant chemoradiotherapy

PURPOSE: This paper aims to investigate the diagnostic performance of magnetic resonance imaging (MRI) in predicting the pathologic stage of locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (CRT) and the role of MRI in selecting patients with a pathologic complete response (ypCR). METHODS: Restaging MRI (yMRI) examinations of 136 patients with LARC treated with neoadjuvant CRT followed by surgery were retrospectively analyzed by two radiologists. All examinations were performed on a 1.5 Tesla MRI machine with a pelvic phased-array coil. T2-weighted turbo spin-echo images and diffusion-weighted imaging were obtained. Histopathologic reports of the surgical specimens were the reference standard. The accuracy, sensitivity, specificity, positive and negative predictive values (PPV and NPV) of yMRI in predicting the pathologic T-stage (ypT), N-stage, and ypCR were calculated. The inter-observer agreement was evaluated using kappa statistics. RESULTS: The yMRI results showed 67% accuracy, 59% sensitivity, 80% specificity, 81% PPV, and 56% NPV in identifying ypT (ypT0-2 versus ypT3-4). In predicting the nodal status, the yMRI results revealed 63% accuracy, 60% sensitivity, 65% specificity, 47% PPV, and 75% NPV. In predicting ypCR, the yMRI results showed 84% accuracy, 20% sensitivity, 92% specificity, 23% PPV, and 90% NPV. The kappa statistics revealed substantial agreement between the two radiologists. CONCLUSION: Utilization of yMRI showed high specificity and PPV in predicting the tumor stage and high NPV in predicting the nodal stage; in addition, yMRI revealed moderate accuracy in the T and N classifications, mainly due to underestimating the tumor stage and overestimating the nodal status. Finally, yMRI revealed high specificity and NPV but low sensitivity in predicting the complete response.

Giant gossypiboma presenting as a pelvic mass.

Gossypiboma is a foreign object, such as a mass of cotton matrix or a sponge, that is left behind in a body cavity during surgery. It is uncommon, mostly asymptomatic, and hard to diagnose. It may be incorrectly diagnosed preoperatively, which can lead to unnecessary invasive diagnostic procedures and operations. It should be included in the differential diagnosis of soft-tissue masses detected in patients with a history of a prior operation. We present a case of 36-year-old female who referred to emergency room with severe abdominal pain and distension. Imaging revealed a giant intra-abdominal mass resembling a soft tissue tumor, but revealed to be a giant gossypiboma caused by a sponge that was forgotten during previous ectopic pregnancy surgery. This case differs from others with the absence of findings supporting gossypiboma such as calcification or trapped gas bubbles and emphasizes the importance of this potentially life-threatening complication of surgery.