Faculty Bibliography

Implantation of an endometriotic lesion within a pelvic or abdominal wall scar is an uncommon but well-described condition that may be the underlying cause of acute or chronic recurrent abdominal or pelvic pain, especially after cesarean section. Radiologists may not consider scar endometriosis when it is encountered at cross-sectional imaging. Cesarean section scars are the most common site of extraovarian or extrauterine endometriosis. The condition also has been identified in other uterine surgery-related scars and in the skin, subcutaneous tissues, and abdominal and pelvic wall musculature adjacent to these scars. The most plausible cause of scar endometriosis is implantation of endometrial stem cells at the surgical site at the time of uterine surgery. Patients with scar endometriosis may be asymptomatic or present with cyclical pain corresponding to the menstrual cycle. Cross-sectional imaging findings vary from the nonspecific to those suggestive of the diagnosis when combined with clinical history. In particular, the presence of blood products in an anterior abdominal wall mass at magnetic resonance (MR) imaging with no other explanation is strongly suggestive of scar endometriosis. Ultrasonography, computed tomography, and MR imaging may be used to depict an endometriotic lesion, exclude endometriosis, or provide evidence for an alternative diagnosis.

Because virtually all patients with colonic cancer will undergo some form of surgical therapy, the role of preoperative imaging is directed at determining the presence or absence of synchronous carcinomas or adenomas and local or distant metastases. In contrast, preoperative staging for rectal carcinoma has significant therapeutic implications and will direct the use of radiation therapy, surgical excision, or chemotherapy. CT of the chest, abdomen, and pelvis is recommended for the initial evaluation for the preoperative assessment of patients with colorectal carcinoma. Although the overall accuracy of CT varies directly with the stage of colorectal carcinoma, CT can accurately assess the presence of metastatic disease. MRI using endorectal coils can accurately assess the depth of bowel wall penetration of rectal carcinomas. Phased-array coils provide additional information about lymph node involvement. Adding diffusion-weighted imaging to conventional MRI yields better diagnostic accuracy than conventional MRI alone. Transrectal ultrasound can distinguish layers within the rectal wall and provides accurate assessment of the depth of tumor penetration and perirectal spread, and PET and PET/CT have been shown to alter therapy in almost one-third of patients with advanced primary rectal cancer. The ACR Appropriateness Criteria((R)) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

BACKGROUND:After observing metaphyseal changes in pediatric and young adult patients with osteosarcoma who were treated with pamidronate, we initiated a retrospective study to identify bone findings on computed radiography of the chest and extremities, chest CT, extremity MRI, and radionuclide bone scans in this population. OBJECTIVE:To review the generalized skeletal imaging findings on computed radiography, CT, and MR examinations in patients with osteosarcoma (OS) receiving pamidronate. MATERIALS AND METHODS/METHODS:A retrospective review of 40 patients with newly diagnosed OS (mean age, 16.5 years) receiving pamidronate with chemotherapy were identified at one institution. Computed radiography, CT, MR, and bone scans on 36 patients were reviewed for osseous changes. RESULTS:Dense metaphyseal bands at the growth plates in long bones, epiphyseal ossification centers, anterior rib ends, sternum and spine were observed. Osseous changes occurred on CT in 69% of patients, and on computed chest radiography in 53%. Bone-within-bone appearance in the spine and ossification centers was identified on computed radiography in 36%. CONCLUSION/CONCLUSIONS:OS patients treated with pamidronate can develop metaphyseal sclerotic bands as well as epiphyseal and vertebral endplate sclerosis progressing to a bone-within-bone appearance. Findings occur more frequently in younger patients with open epiphyses.

BACKGROUND & AIMS/OBJECTIVE:Several risk factors have been identified for the development of recurrent Clostridium difficile infection (CDI) that alter host immunity and disrupt colonic flora. Although the function of the appendix has been debated, its active, gut-associated lymphoid tissue and biofilm production indicate potential roles in recovery from initial CDI and protection against recurrent CDI. We investigated whether the presence or absence of an appendix is associated with CDI recurrence. METHODS:We reviewed the medical records of adult inpatients with CDI who were admitted to a tertiary-care teaching hospital from 2005 to 2007 to identify those with and without an appendix. The primary dependent variable for statistical analysis was CDI recurrence. RESULTS:In a multivariate analysis of 11 clinical variables, the presence of an appendix was associated inversely with CDI recurrence (P < .0001; adjusted relative risk, .398). Age older than 60 years also was associated with CDI recurrence (P = .0280; adjusted relative risk, 2.44). CONCLUSIONS:The presence of an appendix has a significant and independent, inverse association with CDI recurrence, but this finding requires validation in a prospective study. Assessing the presence or absence of an appendix might be useful in predicting CDI recurrence.

OBJECTIVE:The purpose of this article is to retrospectively review the radiologic and clinical findings in patients with angiotensin-converting enzyme inhibitor (ACEI)-induced small-bowel angioedema, with an emphasis on CT findings. MATERIALS AND METHODS/METHODS:Imaging findings, with an emphasis on CT, and clinical characteristics of 20 patients (23 presentations) presenting to two institutions' emergency departments from 1996 through 2010 with ACEI-induced small-bowel angioedema were retrospectively reviewed by two abdominal radiologists who were aware of the diagnosis. Examinations were reviewed in consensus to determine common radiographic findings. RESULTS:Patient age range was 23-83 years (mean, 56 years). Sixteen of the 20 patients were women, and 15 of 20 were obese. All had acute onset of severe abdominal pain. The date of the initial episode prompting CT evaluation ranged from 2 days to 10 years after the start of ACEI therapy (average, 3.3 years). All patients underwent abdominal CT examinations while symptomatic; five patients also underwent a small-bowel series. Three patients underwent urgent surgery for presumed small-bowel ischemia. All patients had resolution of symptoms within 4 days of hospitalization. CT findings included ascites in all patients, small-bowel wall thickening (mean, 1.3 cm), mild dilatation (mean, 2.9 cm), and straightening. There was no small-bowel obstruction. CONCLUSION/CONCLUSIONS:ACEI-induced small-bowel angioedema should be included in the differential diagnosis when patients receiving ACEI therapy present with abdominal complaints and the following combination of findings on CT examination: ascites, small-bowel wall thickening, dilatation without obstruction, and straightening.

Acute aortic dissection (AAD) is the most common aortic catastrophe. The mortality rate of type A dissection approaches 40% to 50% in 48 hours. Causes of death include rupture, aortic insufficiency, or malperfusion involving the coronary arteries, head vessels, visceral arteries, and lower extremities. Other acute aortic conditions can be confused with AAD. Emergent surgery is usually recommended, although there are some situations in which initial management of malperfusion or conservative therapy can be considered prior to proximal aortic repair. Various surgical techniques are employed to manage AAD. This article reviews the etiology, clinical presentations, and management of patients with type A AAD.

Adamantinoma is a rare primary bone malignancy with a predilection for the tibial cortex. Metastases have been reported to the long bones, lung, pleura and spine. We present a 26-year-old pregnant woman with metastatic disease to the posterior cul-de-sac, lungs, liver and retroperitoneum, which collectively have not been previously reported in a single patient to our knowledge.

The diagnostic imaging of patients presenting with right lower quadrant pain and suspected appendicitis may be organized according to age and gender and to the presence or absence of "classic" signs and symptoms of acute appendicitis. Among adult patients presenting with clinical signs of acute appendicitis, the sensitivity and specificity of CT are greater than those of ultrasound, with improved performance when CT is performed with intravenous contrast. The use of rectal contrast has been associated with decreased time in the emergency department. Computed tomography has also been shown to reduce cost and negative appendectomy rates. Both CT and ultrasound are also effective in the identification of causes of right lower quadrant pain unrelated to appendicitis. Among pediatric patients, the sensitivity and specificity of graded-compression ultrasound can approach those of CT, without the use of ionizing radiation. Performing MRI after inconclusive ultrasound in pregnant patients has been associated with sensitivity and specificity of 80% to 86% and 97% to 99%, respectively. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.