Kostaki G. Bis

Penetrating atherosclerotic ulcers of the aorta

PURPOSE This study investigates the natural history and optimal imaging modality of penetrating atherosclerotic ulcers of the aorta. METHODS We reviewed our experience with 29 penetrating ulcers in 18 patients. Computed tomography (17 patients), magnetic resonance imaging (nine patients), and aortography (five patients) were used for diagnosis and follow-up. Patients were typically elderly (average age 74 years) and had hypertension and coronary artery disease. Ulcers were most common in the distal descending thoracic aorta (31%) and were characterized by a discrete ulcer crater (100%) and thickened aortic wall (89%). Modes of presentation included chest or back pain in four patients, distal embolization in two patients, and abnormal chest radiography results in one; the remaining were incidental findings. RESULTS Follow-up was available in ten patients with 17 ulcers from 1 to 7 years. Recurrent pain occurred in two patients, recurrent embolization occurred in one patient, and seven patients remained symptom free. Progression to saccular pseudoaneurysm occurred in five ulcers, and fusiform aneurysm occurred in two ulcers. Two ulcers were associated with an increase in aortic diameter, and nine ulcers did not change. There were no cases of aortic dissection or rupture in the follow-up period. There were no deaths and only one patient underwent resection. CONCLUSION The natural history of penetrating atherosclerotic ulcers is one of progressive aortic enlargement, with saccular and fusiform aneurysms the result if follow-up is sufficient. Aortic dissection, aortic rupture, and embolization can also occur but are less common. Contrast-enhanced computed tomography is the primary imaging modality.

CARCINOMA OF THE CERVIX: PREDICTIVE VALUE OF CLINICAL AND MAGNETIC RESONANCE (MR) IMAGING ASSESSMENT OF PROGNOSTIC FACTORS

PURPOSE This retrospective study assesses the predictive value of magnetic resonance imaging (MRI) to identify high risk cervical cancer patients. METHODS AND MATERIALS The MRI evaluation of morphologic risk factors in patients with invasive cervical carcinoma treated with definitive radiation therapy were correlated with clinical factors and with complete tumor regression (CTR) at 6 months, tumor local control (TLC), and patient outcome at 12 months after irradiation. Sixty-six patients, median age 44.5 years, with bulky Stage I or greater disease were included in the study. RESULTS In univariate analysis, clinical International Federation of Gynecology and Obstetrics (FIGO) stage had significant correlation with patient outcome, but it correlated poorly with complete tumor regression and tumor local control. In contrast, MRI stage showed significant correlation with complete tumor regression, tumor local control, and disease-free survival at 12 months. When each stage was analyzed separately, the greatest difference was demonstrated between clinical and MRI assignment of stage Ib disease. MRI Stage Ib disease significantly correlated with all three categories analyzed, while clinical Stage Ib did not. Superiority of MRI assessment of low stage disease was also evident in the detection of lymph node metastasis. Significant risk for nodal metastasis was related to tumor size greater than 4 cm, invasion of the parametria and urinary bladder, and stage of the disease. CONCLUSION The multivariate analysis demonstrated that the most related variables in order of significance were the presence of juxta-regional and paraaortic lymph nodes, patient age, tumor size, and MRI tumor stage. This study demonstrates the value of MR imaging as an adjunct to clinical assessment of bulky invasive cervical cancer, rendering more complete assessment of morphologic risk factors important in patient prognosis.

Contrast‐enhanced breath‐hold three‐dimensional magnetic resonance angiography in the evaluation of renal arteries: Optimization of technique and pitfalls

The authors describe the optimization of a contrast‐enhanced, breath‐held, three‐dimensional magnetic resonance angiography (CE‐BH‐3DMRA) technique in the assessment of the renal arteries and compare its utility with conventional x‐ray angiography (XRA). Signal optimization using specific pulse sequence parameters was based on the patients circulatory conditions, injection rate, and pulse sequence timing. Fifty‐one patients (27 M, 24 F; mean age 69.7 years) were evaluated with CE‐BH‐3DMRA and XRA. All patients had an MR angiogram 3 months either before or after XRA. A test bolus study was performed for accurate assessment of transit time in each patient. A total of 51 patients (115 vessels) were studied in which the sensitivity and specificity for all renal artery stenoses including the proximal and mid‐renal arterial segments were 96% and 92%, respectively. In‐stent stenosis could only be diagnosed by quantifying flow beyond the stent using an additional triggered phase contrast cine pulse sequence. A total of 11 accessory renal arteries were correctly identified. In addition, fibromuscular dysplasia in two patients and stents in three patients were correctly identified on MRA. J. Magn. Reson. Imaging 2000;12:912–923.

Pelvic fistulas : appearances on MR images

Abstract.Background: This multi-institutional study examines appearances of pelvic fistulas on magnetic resonance (MR) images. Methods: MR images of 46 patients with documented fistulas from five teaching hospitals were retrospectively reviewed. All patients underwent T1-weighted (T1WI), T2-weighted (T2WI), and intravenous gadolinium chelate-enhanced T1-weighted (Gd-T1WI) images. Imaging sequences were separately and then collectively reviewed. The following determinations were made: fistula detection, fistula morphology and signal intensity, and the presence of associated abnormalities. Fistulas were classified into two categories: (1) fistulas that communicate with the bladder and (2) fistulas that do not communicate with the bladder. Fistulas within these two groups were subclassified further. The presence of fistulas was documented by surgery (five patients), endoscopy (six patients), fistulogram (20 patients), or physical exam (15 patients). Results: Among the 46 patients, 53 fistulas were documented by means other than MR. Overall T1WI, T2W1 and Gd-T1WI images demonstrated 23, 31, and 39 of 53 fistulas, respectively. Gd-T1W1 detected significantly more fistulas than T1W1 (p < 0.05). Bladder fistulas were better shown on Gd-T1WI (8/15 fistulas) than on T1WI and T2WI (2/15 and 3/15) (p < 0.05). Nonbladder fistulas were demonstrated by T1WI, T2WI, and Gd-T1WI images in 21, 28, and 31 of 38 fistulas, respectively. Among all fistulas, perianal fistulas (a subcategory of nonbladder fistula) had the highest detection by T1WI, T2WI, and Gd-T1WI in 19, 20 and 22 of 23 fistulas, respectively. On T1WI, 19 of 23 detected fistulas were low in signal intensity. On T2WI, 28 of 39 detected fistulas were high in signal intensity. On Gd-T1WI images, 29 of 40 fistulas were low in signal intensity, with enhanced tract wall. Conclusion: Bladder fistulas were best shown on Gd-T1WI, which was significantly greater than on T1WI or T2WI. Nonbladder fistulas were comparably shown by all techniques, with all performing modestly well. Perianal fistulas were shown equally well by all MR sequences and were the fistulas demonstrated with the highest sensitivity on MR images.

Enhancement Performance of a 64-Slice Triple Rule-Out Protocol vs 16-Slice and 10-Slice Multidetector CT-Angiography Protocols for Evaluation of Aortic and Pulmonary Vasculature

Objective: To compare the enhancement of the pulmonary and aortic vasculature between a biphasic injection 64-slice, a single-phase injection 16-slice, and a single-phase injection 10-slice multidetector computed tomographic (CT) angiography (CTA) protocols. Methods: With institutional review board approval and Health Insurance Portability and Accountability Act compliance, 50 patients (16 men, 34 women; mean age, 51.5 years; range, 30-75 years) with atypical chest pain from the emergency department were scanned using a triple rule-out protocol on a 64-slice CT scanner. Pulmonary enhancement was compared with 50 patients (21 men, 29 women; mean age, 65.6 years; range, 38-90 years) imaged with a single-phase 16-slice pulmonary angiography protocol. Aortic enhancement was compared with 24 patients (12 men, 12 women; mean age, 66.1; range, 34-92 years) who were imaged with a 16-slice aortic dissection CTA protocol and to 25 patients (15 men, 10 women; mean age, 50.8 years; range, 20-83 years) imaged with a 10-slice aortic dissection CTA protocol. A 2-tailed Student t test or sign test was used to assess significant differences from a vascular attenuation cutoff value of 250 Hounsfield units (HU). Results: Individual mean pulmonary arterial and aortic attenuation values were statistically significantly less than 250 HU for the 16- and 10-slice protocols and statistically significantly more than 250 HU for the 64-slice protocols (P < 0.05). Mean pooled pulmonary attenuation values were more than 250 HU in 18% (9/50) of the 16-slice and in 93% (39/42) of the 64-slice protocols. Mean pooled aortic attenuation values were more than 250 HU in 18.4% (9/49) of the 10- and 16- and in 100% (42/42) of the 64-slice protocols. Conclusions: The triple rule-out 64-slice biphasic injection breath hold CTA protocol provides significantly higher attenuation of aortic and pulmonary vasculature compared with our current 10- and 16-slice protocols.

Normal and variant coronary arterial and venous anatomy on high-resolution CT angiography.

OBJECTIVE This article displays the normal and variant anatomy of the coronary arteries and subjacent cardiac veins using a high-resolution 64-MDCT scanner. CONCLUSION Knowledge of the anatomy of the coronary arteries and subjacent cardiac veins as displayed with maximum intensity and volume-rendered projections is important for correct image interpretation of coronary CT angiography examinations.

Juxtaglomerular Cell Tumor: Mr Findings

Juxtaglomerular (JG) cell tumor is a rare benign neoplasm of the kidney that typically presents with hypertension, secondary hyperaldosteronism, hypocalcemia, and hyperreninism. We describe a case of JG cell tumor diagnosed with MRI.

A Comprehensive Approach to CT Radiation Dose Reduction: One Institution’s Experience

OBJECTIVE The purpose of this article is to review the process of creating and implementing a comprehensive plan to reduce diagnostic radiation exposure at our institution. CONCLUSION This process, which was initiated by forming a radiation dose reduction committee, addressed several different issues to improve patient safety. These include avoidance of unnecessary CT examinations, adjusting individual scanning parameters, revising protocols, use of shielding and dose monitoring, and implementing computer-based dose modulation software as well as educating referring physicians and radiologic technologists.

Contrast-enhanced three-dimensional MR angiography of the pulmonary vascular tree

Contrast-enhanced three-dimentional MR angiography has evolved into a promising technique in the study of the pulmonary vasculature. Both congenital and acquired entities can be now morphologically demonstrated in a non-invasive manner obviating the need for conventional pulmonary angiography. Due to spatial resolution limitations, however, it is still premature to routinely apply the method in the detection of small subsegmental emboli, in cases of suspected pulmonary embolism, and further technical developments will be required. In this paper we present a spectrum of congenital and acquired disorders affecting the pulmonary vascular tree as demonstrated with contrast-enhanced three-dimensional MR angiography.

3D breath-hold contrast-enhanced MRA: a preliminary experience in aorta and iliac vascular disease.

PURPOSE Our goal was to describe a 3D breath-hold (3D BH) contrast-enhanced MRA technique and apply the technique to patients with known or suspected aortic and iliac artery disease. METHOD A fat-suppressed 3D GRE pulse sequence was designed with a total of 16 partition encodings. This took < 24 s for data acquisition in the abdomen and pelvis and was easily achieved during a single breath-hold. The technique was applied to 26 patients who presented with either known or suspected abdominal aortic or iliac vascular diseases. For comparison, in 19 patients a 2D TOF MRA pulse sequence with a traveling saturation band was used. Angiographic correlation was made in 18 studies. RESULTS The 3D BH MRA was easily applicable in the evaluation of vascular anatomy and pathology. In three cases, it was superior to 2D TOF and conventional angiography for visualizing clot within the wall of an aneurysm in the abdominal aorta. In 20 cases, both MRA techniques overestimated the degree of stenosis in the lower peripheral vessels; however, this was more pronounced on 2D TOF. In five cases, the aneurysm wall was clearly defined by 3D BH MRA, whereas there was considerable signal loss in 2D TOF due to complex flow. With 3D BH MRA, the entire vessel territory both in abdominal aorta and in iliac vessels was visualized in all cases without signal falloff in the FOV. Breath-holding provided static images of the vessels that were free of blurring due to respiratory motion. CONCLUSION Preliminary experience suggests that 3D BH with its distinct advantage of speed may serve as a useful screening tool for patients who cannot have conventional angiography or tolerate a lengthy MR examination of the abdominal aorta and iliac arteries.