Use of intra‐arterial multi‐detector row CT angiography for the evaluation of an ischaemic limb in a patient with renal impairment

The vastly improved scanning speed and z‐axis resolution afforded by multi‐detector technology has allowed CT to refine its traditional roles and to explore many new applications in imaging. We present a case report of a patient with renal failure and an ischaemic leg, which illustrates a useful new CT vascular imaging application. By carrying out 16‐channel multi‐detector row CT angiography through a sheath introduced into the common femoral artery, we obtained a high‐quality angiographic image of the affected leg, using only 30 mL of iodinated contrast material. The examination definitively showed the number, distribution and patency of the tibial run‐off arteries, with significant influence on the patient‘s subsequent clinical management. This simple and relatively minimally invasive technique is useful in peripheral vascular imaging, when conventional CT angiography using a large volume of i.v. contrast and MR angiography are unsuitable or unavailable.     

Computed tomography pulmonary angiography with pelvic venography in the evaluation of thrombo‐embolic disease

A prospective study was performed to evaluate the usefulness of CT pelvic venography (CTV) in the detection of pelvic vein thrombosis in patients referred for CT pulmonary angiography (CTPA) for suspected pulmonary embolism. Fifty consecutive patients referred for CTPA had CTV performed at the time of CTPA. All patients had duplex ultrasound (DUS) of the lower limb veins for evaluation of deep venous thrombosis (DVT) within 24 h of the CT study. Twelve (24%) of the 50 patients had pulmonary embolism diagnosed on CTPA. Associated DVT was detected in six of these patients; two cases were detected by CTV alone, while one case was detected by both CTV and DUS. The remaining three cases had DVT diagnosed by DUS alone. In the 38 patients with a negative CTPA, three patients had venous thrombus diagnosed by CTV. Of these three patients, two had a negative DUS study. CTV therefore led to a definitive imaging diagnosis of thrombo‐embolic disease in two (4%) more patients. CTV adds little time and cost to the CTPA examination and leads to a moderate increase in definite imaging diagnosis of thrombo‐embolic disease.     

Contrast‐enhanced magnetic resonance angiography of the peripheral arteries: Technique,tips, pitfalls and problems

Contrast‐enhanced magnetic resonance angiography is a reliable way to assess peripheral vascular disease. This article reviews the basic physics behind this technique and discusses our institution's experience with regard to the clinical role, recent advances in image acquisition and use of contrast agents. Problems that can affect image quality and interpretation are also highlighted.     

Computed tomography and 18F-FDG positron emission tomography for therapy control of Hodgkin's and non-Hodgkin's lymphoma patients: when do we really need FDG-PET?

BACKGROUND: The aim of this study was to evaluate the accuracy of computed tomography (CT) and [(18)F]fluoro-deoxy-d-glucose positron emission tomography (FDG-PET) for prediction of progression-free survival of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) patients after completion of therapy. PATIENTS AND METHODS: CT and FDG-PET were performed in 40 HD, 17 indolent NHL and 44 aggressive NHL patients (29 women, 72 men; aged 41+/-14 years) in a median of 2 months after therapy. Progression-free survival was evaluated using the Kaplan-Meier method. Independent prognostic factors were identified by means of Cox proportional hazards model. RESULTS: CT imaging results were progressive disease (PD) in five, stable disease (SD) in 57, and partial response (PR) or complete remission (CR) in 39 patients. FDG-PET suggested residual lymphoma in 24 patients. Three-year progression-free survival rates after exclusion of five PD patients were: 100% (PET negative; CT: PR or CR), 81% (PET negative; CT: SD), 21% (PET positive; CT: SD) and 0% (PET positive; CT: PR). FDG-PET (P<0.0001) and bulky disease (P <0.05) were identified as independent prognostic variables. CONCLUSIONS: Among lymphoma patients with PR and SD on CT, FDG-PET discriminated those destined to progress into a low risk of < or =20% and a high risk for recurrence of > or =80%.     

Performance of magnetic resonance imaging in pulmonary fungal disease compared to high‐resolution computed tomography

To evaluate the performance of magnetic resonance imaging (MRI) compared to computed tomography (CT) in patients diagnosed with pulmonary mycosis. We prospectively included 21 patients diagnosed with pulmonary mycosis between January 2013 and October 2014. Inclusion criteria were presence of respiratory symptoms, histopathological diagnosis of mycosis and absence of mycosis treatment. Reviewers identified one predominant imaging pattern per patient: nodular, reticular or airspace pattern. Afterwards, all CT findings were analysed separately per lobe and compared to MRI. Nodular pattern was the most common found (CT: 76.20%; MRI: 80.96%), followed by airspace pattern (CT and MRI: 9.52%) and reticular (CT: 9.52%; MRI: 4.76%). Compared to CT, MRI performance varied according to radiological finding and pulmonary region. For nodules, MRI presented high sensitivity (100% [95% CI: 93.52‐100]) and specificity (100% [95% CI: 92.00‐100]). For bronchiectasis and septal thickening, there were poorer positive predictive values (33.33% [95% CI: 1.77‐87.47]; and 83.33% [95% CI: 50.88‐97.06] respectively). As specificity and negative predictive value had superior results than sensitivity and positive predictive value, rather than for diagnosis of this condition, MRI might be more considered for the follow‐up of patients with pulmonary mycosis, an alternative to multiple radiation exposures with CT follow‐up.     

18F‐Fluorodeoxyglucose positron emission tomography/computed tomography for the detection of recurrent bone and soft tissue sarcoma

BACKGROUND:

The clinical utility of modern hybrid imaging modalities for detecting recurrent bone or soft tissue sarcoma remains to be determined. In this report, the authors present a clinical study on the diagnostic accuracy and incremental value of integrated ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) in patients with a history of sarcoma who have clinically suspected disease recurrence.

METHODS:

Forty‐three patients who had a history of bone or soft tissue sarcoma and had documented complete remission underwent ¹⁸F‐FDG PET/CT. Image analysis was performed independently for ¹⁸F‐FDG PET (n = 43) and for contrast‐enhanced spiral CT (CE‐CT) (n = 30) by 2 separate readers, whereas combined ¹⁸F‐FDG PET/CT (n = 43) images were analyzed in consensus by both readers. Imaging findings were rated on a 5‐point scale and finally were reported as malignant, benign, or equivocal. Imaging findings were validated either by histopathology (n = 24) or by clinical follow‐up (n = 19).

RESULTS:

¹⁸F‐FDG PET/CT had greater sensitivity and specificity compared with CE‐CT alone (94% and 92% vs 78% and 67%, respectively), resulting in significantly greater accuracy (93% vs 73%; P = .03). ¹⁸F‐FDG PET/CT was particularly superior regarding detection of local recurrence or soft tissue lesions (sensitivity and specificity: 83% and 100% vs 50% and 100%, respectively) or bone metastases (100% and 100% vs 85% and 88%, respectively).

CONCLUSIONS:

¹⁸F‐FDG PET/CT had greater diagnostic accuracy in the detection of recurrent bone or soft tissue sarcoma compared with CE‐CT alone. The detection of local recurrence was the most evident advantage of ¹⁸F‐FDG PET/CT over CE‐CT. Cancer 2013. © 2012 American Cancer Society.     

Four‐dimensional computed tomography (4DCT): A review of the current status and applications

The applications of conventional computed tomography (CT) have been widely researched and implemented in clinical practice. A recent technological innovation in the field of CT is the emergence of four‐dimensional computed tomography (4DCT), where a three‐dimensional computed tomography volume containing a moving structure is imaged over a period of time, creating a dynamic volume data set. 4DCT has previously been mainly utilised in the setting of radiation therapy planning, but with the development of wide field of view CT, 4DCT has opened major avenues in the diagnostic arena. The aim of this study is to provide a comprehensive narrative review of the literature regarding the current clinical applications of 4DCT. The applications reviewed include both routine diagnostic usage as well as an appraisal of the current research literature. A systematic review of the studies related to 4DCT was conducted. The Medline database was searched using the MeSH subject heading ‘Four‐Dimensional Computed Tomography’. After excluding non‐human and non‐English papers, 2598 articles were found. Further exclusion criteria were applied, including date range (since wide field of view CT was introduced in 2007), and exclusion of technical/engineering/physics papers. Further filtration of papers included identification of Review papers. This process yielded 67 papers. Of these, exclusion of papers not specifically discussing 4DCT (cone beam, 4D models) yielded 38 papers. As part of the review, the technique for 4DCT is described, with perspectives as to how it has evolved and its benefits in different clinical indications.     

Computed tomography in miliary tuberculosis: Comparison with plain films,bronchoalveolar lavage,pulmonary functions and gas exchange

Computed tomography (CT) of the chest, pulmonary function tests, bronchoalveolar lavage (BAL) and arterial blood gas analysis were performed in 26 patients with non-HIV miliary tuberculosis (MTB). CT was repeated after treatment in 11 patients. Nodular lesions were characteristically seen on CT. CT showed discrete and fine nodules in five patients in whom the lesions appeared to be larger than miliary on chest X-rays. Coalescing nodular lesions were noted on chest X-rays (n= 7) and CT (n= 18). Consolidation (n= 6), cavitation (n= 4), fibrosis (n= 9) and air trapping (n= 14) were detected on CT only. During follow up, air trapping increased h = 14) and in some patients it appeared for the first time (n= 2). Lymph node enlargement and calcification were seen on both chest X-rays (n= 9 and (n= 3, respectively) and CT (n= 12 and n= 7, respectively). Pleural involvement was also seen in chest X-rays (n= 4) and CT (n= 5). Total lung capacity was higher in patients with a chest X-ray score > 10. Similarly a higher total cell count in BAL fluid was observed in patients with a CT score > 10. It is concluded from this study that CT is superior to chest X-rays in detecting nodular lesions, lymphadenopathy and air trapping in patients with MTB.     

Cone-beam computed tomography for on-line image guidance of lung stereotactic radiotherapy: localization, verification, and intrafraction tumor position

PURPOSE: Cone-beam computed tomography (CBCT) in-room imaging allows accurate inter- and intrafraction target localization in stereotactic body radiotherapy of lung tumors. METHODS AND MATERIALS: Image-guided stereotactic body radiotherapy was performed in 28 patients (89 fractions) with medically inoperable Stage T1-T2 non-small-cell lung carcinoma. The targets from the CBCT and planning data set (helical or four-dimensional CT) were matched on-line to determine the couch shift required for target localization. Matching based on the bony anatomy was also performed retrospectively. Verification of target localization was done using either megavoltage portal imaging or CBCT imaging; repeat CBCT imaging was used to assess the intrafraction tumor position. RESULTS: The mean three-dimensional tumor motion for patients with upper lesions (n = 21) and mid-lobe or lower lobe lesions (n = 7) was 4.2 and 6.7 mm, respectively. The mean difference between the target and bony anatomy matching using CBCT was 6.8 mm (SD, 4.9, maximum, 30.3); the difference exceeded 13.9 mm in 10% of the treatment fractions. The mean residual error after target localization using CBCT imaging was 1.9 mm (SD, 1.1, maximum, 4.4). The mean intrafraction tumor deviation was significantly greater (5.3 mm vs. 2.2 mm) when the interval between localization and repeat CBCT imaging (n = 8) exceeded 34 min. CONCLUSION: In-room volumetric imaging, such as CBCT, is essential for target localization accuracy in lung stereotactic body radiotherapy. Imaging that relies on bony anatomy as a surrogate of the target may provide erroneous results in both localization and verification.     

Giant spinal arachnoid cysts: Computed tomography,magnetic resonance imaging and magnetic resonance myelography correlation

Two cases of giant spinal arachnoid cysts, one of them being symptomatic, are discussed, along with their CT, MRI and MR myelography findings.     

Usefulness of dual‐phase cone‐beam computed tomography during arteriography and automated tumour‐feeder detection software in transarterial embolization for obscure arterial bleeding in the abdomen

We report the usefulness of dual‐phase cone‐beam computed tomography during angiography (CBCTA) and automated tumour‐feeder detection software (AFD) in transarterial embolization (TAE) for three consecutive cases of obscure arterial bleeding in the abdomen. Two patients presented with lower gastrointestinal bleeding and one showed bleeding into the pancreatic pseudocyst. Superior mesenteric or common hepatic angiography did not demonstrate extravasation, but dual‐phase CBCTA and AFD could identify extravasation and an access route to the bleeding point. TAE with gelatin sponge particles and a microcoil was successfully performed under AFD guidance in all patients without any complication, and haemostasis could be achieved.     

Computed tomography screening for lung cancer: review of screening principles and update on current status

Screening for lung cancer with low-dose computed tomography (CT) is controversial. In favor of screening, lung cancer is the leading cause of cancer death in the United States, and those at greatest risk are identified readily on the basis of age and smoking history. In addition, it is well established that CT is far more sensitive than chest radiography in detecting lung cancer when it is small and asymptomatic. Furthermore, very high rates of survival were reported recently for screen-detected lung cancers in a large, multinational, single-arm observational study. However, a reduction in lung cancer mortality has not been demonstrated to date, and a recent longitudinal study with a simulated control group suggested little or no mortality reduction. In addition, there are important harms from CT screening, including false-positive test results and overdiagnosis. Furthermore, healthcare resources are finite. Therefore, even if the benefits do outweigh the harms, the cost-effectiveness of CT screening for lung cancer still will need to be considered in the context of competing healthcare alternatives. The objectives of this article were 3-fold: 1) to review the basic principles of screening and study designs related to cancer screening, 2) to summarize the results of the observational and analytical studies of CT screening that have been reported to date, and 3) to describe the design of the 2 ongoing, randomized controlled trials of CT screening and what may be learned from these studies in the near future.     

Deep‐seated thoracic and abdominal masses: Usefulness of ultrasound and computed tomography guidance in fine needle aspiration cytology diagnosis

Fine needle aspiration cytology (FNAC) was performed under ultrasound and CT guidance in 120 cases. These included abdominal masses (85 cases) and thoracic masses (35 cases) biopsied over a two and a half year period (March 1996 to September 1998). The aim of this study was to assess the contribution of clinico‐imaging evaluation and image‐guided FNAC to the management of patients with deep‐seated mass lesions. Aspirations in the abdomen were performed from various anatomic sites such as liver (56 cases), lymph nodes (18 cases), gastrointestinal tract (three cases), pancreas (six cases), and kidney (two cases). In the thorax, biopsy was performed in the lung (19 cases) and mediastinum (13 cases). In 112 cases (93.4%) FNAC was diagnostic. Of the lesions that were successfully aspirated, 85% were ≤ 5 cm in size. No major complication was encountered. All the successful aspirates could be defined as malignant or non‐malignant, but tissue differentiation was possible in 63.7% of malignant lesions and 53.8% of benign lesions. Combined clinical and imaging evaluation for malignancy showed 80% sensitivity and 59% specificity. Although clinicoradiological parameters themselves have certain limitations in diagnosing benign versus malignant lesions, in conjunction with guided FNA they are very accurate and safe in diagnosing deep‐seated mass lesions in the thorax and in the abdomen. However, the role of FNA in tissue differentiation of solid lesions such as lymphoma requires further study.